sub-humid cropping environment: Topics by WorldWideScience.org

Sample records for sub-humid cropping environment

Cropping Systems and Climate Change in Humid Subtropical Environments

Directory of Open Access Journals (Sweden)

Ixchel M. Hernandez-Ochoa

2018-02-01

Full Text Available In the future, climate change will challenge food security by threatening crop production. Humid subtropical regions play an important role in global food security, with crop rotations often including wheat (winter crop and soybean and maize (summer crops. Over the last 30 years, the humid subtropics in the Northern Hemisphere have experienced a stronger warming trend than in the Southern Hemisphere, and the trend is projected to continue throughout the mid- and end of century. Past rainfall trends range, from increases up to 4% per decade in Southeast China to −3% decadal decline in East Australia; a similar trend is projected in the future. Climate change impact studies suggest that by the middle and end of the century, wheat yields may not change, or they will increase up to 17%. Soybean yields will increase between 3% and 41%, while maize yields will increase by 30% or decline by −40%. These wide-ranging climate change impacts are partly due to the region-specific projections, but also due to different global climate models, climate change scenarios, single-model uncertainties, and cropping system assumptions, making it difficult to make conclusions from these impact studies and develop adaptation strategies. Additionally, most of the crop models used in these studies do not include major common stresses in this environment, such as heat, frost, excess water, pests, and diseases. Standard protocols and impact assessments across the humid subtropical regions are needed to understand climate change impacts and prepare for adaptation strategies.
Crop coefficients for winter wheat in a sub-humid climate regime

DEFF Research Database (Denmark)

Kjærsgaard, Jeppe Hvelplund; Plauborg, Finn; Mollerup, Mikkel

2008-01-01

Estimations of evapotranspiration (ET) from natural surfaces are used in a large number of applications such as agricultural water management and water resources planning. Lack of reliable, cheap and easy-to-use instruments, associated with the chaotic and varying nature of the meteorological...... coefficients for a winter wheat crop growing under standard conditions, i.e. not short of water and growing under optimal agronomic conditions, were estimated for a cold sub-humid climate regime. One of the two methods used to estimate ET from a reference crop required net radiation (Rn) as input. Two sets...... of coefficients were used for calculating Rn. Weather data from a meteorological station was used to estimate Rn and ET from the reference crop. The winter wheat ET was measured using an eddy covariance system during the main parts of the growing seasons 2004 and 2005. The meteorological data and field...
Effective crop evapotranspiration measurement using time-domain reflectometry technique in a sub-humid region

Science.gov (United States)

Srivastava, R. K.; Panda, R. K.; Halder, Debjani

2017-08-01

The primary objective of this study was to evaluate the performance of the time-domain reflectometry (TDR) technique for daily evapotranspiration estimation of peanut and maize crop in a sub-humid region. Four independent methods were used to estimate crop evapotranspiration (ETc), namely, soil water balance budgeting approach, energy balance approach—(Bowen ratio), empirical methods approach, and Pan evaporation method. The soil water balance budgeting approach utilized the soil moisture measurement by gravimetric and TDR method. The empirical evapotranspiration methods such as combination approach (FAO-56 Penman-Monteith and Penman), temperature-based approach (Hargreaves-Samani), and radiation-based approach (Priestley-Taylor, Turc, Abetw) were used to estimate the reference evapotranspiration (ET0). The daily ETc determined by the FAO-56 Penman-Monteith, Priestley-Taylor, Turc, Pan evaporation, and Bowen ratio were found to be at par with the ET values derived from the soil water balance budget; while the methods Abetw, Penman, and Hargreaves-Samani were not found to be ideal for the determination of ETc. The study illustrates the in situ applicability of the TDR method in order to make it possible for a user to choose the best way for the optimum water consumption for a given crop in a sub-humid region. The study suggests that the FAO-56 Penman-Monteith, Turc, and Priestley-Taylor can be used for the determination of crop ETc using TDR in comparison to soil water balance budget.
Impacts of Present and Future Climate Variability On Agriculture and Forestry in the Humid and Sub-Humid Tropics

International Nuclear Information System (INIS)

Zhao, Y.; Wang, C.; Wang, S.; Tibig, Lourdes V.

2005-01-01

Although there are different results from different studies, most assessments indicate that climate variability would have negative effects on agriculture and forestry in the humid and sub-humid tropics. Cereal crop yields would decrease generally with even minimal increases in temperature. For commercial crops, extreme events such as cyclones, droughts and floods lead to larger damages than only changes of mean climate. Impacts of climate variability on livestock mainly include two aspects; impacts on animals such as increase of heat and disease stress-related death, and impacts on pasture. As to forestry, climate variability would have negative as well as some positive impacts on forests of humid and sub-humid tropics. However, in most tropical regions, the impacts of human activities such as deforestation will be more important than climate variability and climate change in determining natural forest cover
Mixed crop-livestock production systems of smallholder farmers in sub-humid and semi-arid areas of Zambia

International Nuclear Information System (INIS)

Lungu, J.C.N.

2002-01-01

Livestock production activities among small-scale farmers of semi-arid (Agro-ecological zone 1) and sub-humid (Agro-ecological zone 2) areas of Zambia are integrated with crop production activities in what is termed as crop/livestock farming system. This is a closed system in which production of one enterprise depends on the other. In Zambia, crop production depends on draught animals for tillage of cropping area, animal manure for fertilisation of crops while livestock depend on crop residues for dry season feeding. Good quality grass is generally available in adequate amounts to support reasonable level of livestock productivity during the rainy season. But livestock rely on low quantity and poor quality, highly fibrous perennial grass from veld and fibrous crop residues during the dry season. These resources are inadequate to support optimum livestock productivity activities. Poor nutrition results in low rates of reproduction and production as well as increased susceptibility to diseases. With the increasing human population cropping land is expanding, leading to increased production of crop residues. This has however, reduced the grazing land available for ruminant production. In Zambia large quantities of crop residues (stovers, husks and straws, legume tops and hulls, sugar cane tops, cassava leaves, potato vines, etc.) are left in the field where they are wasted each year because small-scale farmers lack the knowledge on how best to use them. There is a need to find ways to reverse this situation by adapting known and workable technologies to local conditions and by introducing new approaches for improving the use of crop residues and poor quality fibrous feeds. Efforts should also be made to enlarge feed resource base. The technologies should be simple and effective. In the presence of a dynamic market system, livestock production in a crop/livestock system could be intensified and made profitable for small-scale farmers. (author)
Influence of cover crop treatments on the performance of a vineyard in a humid region

Energy Technology Data Exchange (ETDEWEB)

Trigo-Córdoba, E.; Bouzas-Cid, Y.; Orriols-Fernández, I.; Díaz-Losada, E.; Mirás-Avalos, J.M.

2015-07-01

Vineyards are usually managed by tilling the inter-rows to avoid competition from other plants for soil water and nutrients. However, in humid and sub-humid climates, such as that of NW Spain, cover crops may be an advantage for controlling vine vegetative growth and improving berry composition, while reducing management costs. The current study was conducted over three consecutive growing seasons (2012-2014) to assess the effects of establishing three permanent cover crop treatments on water relations, vine physiology, yield and berry composition of a vineyard of the red cultivar ‘Mencía’ (Vitis vinifera L.) located in Leiro, Ourense. Treatments consisted of four different soil management systems: ST, soil tillage; NV, native vegetation; ER, English ryegrass (Lolium perenne L.); and SC, subterranean clover (Trifolium subterraneum L.). Midday stem water potential was more negative in the native vegetation treatment, causing significant reductions in leaf stomatal conductance on certain dates. Total vine leaf area and pruning weight was reduced in the cover crop treatments in the last year of the experiment. Yield was unaffected by the presence of a cover crop. No significant differences among treatments were observed for berry composition; however, wines were positively affected by the SC treatment (higher tannin content and colour intensity and lower malic acid concentration when compared with ST). Wines from the cover crop treatments were preferred by taste panelists. These results indicate that in humid climates cover crop treatments can be useful for reducing vine vegetative growth without compromising yield and berry quality. (Author)
Impacts of climate change on cropping patterns in a tropical, sub-humid watershed

Science.gov (United States)

Zwart, Sander J.; Hein, Lars

2018-01-01

In recent decades, there have been substantial increases in crop production in sub-Saharan Africa (SSA) as a result of higher yields, increased cropping intensity, expansion of irrigated cropping systems, and rainfed cropland expansion. Yet, to date much of the research focus of the impact of climate change on crop production in the coming decades has been on crop yield responses. In this study, we analyse the impact of climate change on the potential for increasing rainfed cropping intensity through sequential cropping and irrigation expansion in central Benin. Our approach combines hydrological modelling and scenario analysis involving two Representative Concentration Pathways (RCPs), two water-use scenarios for the watershed based on the Shared Socioeconomic Pathways (SSPs), and environmental water requirements leading to sustained streamflow. Our analyses show that in Benin, warmer temperatures will severely limit crop production increases achieved through the expansion of sequential cropping. Depending on the climate change scenario, between 50% and 95% of cultivated areas that can currently support sequential cropping or will need to revert to single cropping. The results also show that the irrigation potential of the watershed will be at least halved by mid-century in all scenario combinations. Given the urgent need to increase crop production to meet the demands of a growing population in SSA, our study outlines challenges and the need for planned development that need to be overcome to improve food security in the coming decades. PMID:29513753
Degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} perovskite materials upon exposure to humid air

Energy Technology Data Exchange (ETDEWEB)

Shirayama, Masaki; Kato, Masato; Fujiseki, Takemasa; Hara, Shota; Kadowaki, Hideyuki; Murata, Daisuke; Fujiwara, Hiroyuki, E-mail: fujiwara@gifu-u.ac.jp [Department of Electrical, Electronic and Computer Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Miyadera, Tetsuhiko; Sugita, Takeshi; Chikamatsu, Masayuki [Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8568 (Japan)

2016-03-21

Low stability of organic-inorganic perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) solar cells in humid air environments is a serious drawback which could limit practical application of this material severely. In this study, from real-time spectroscopic ellipsometry characterization, the degradation mechanism of ultra-smooth CH{sub 3}NH{sub 3}PbI{sub 3} layers prepared by a laser evaporation technique is studied. We present evidence that the CH{sub 3}NH{sub 3}PbI{sub 3} degradation in humid air proceeds by two competing reactions of (i) the PbI{sub 2} formation by the desorption of CH{sub 3}NH{sub 3}I species and (ii) the generation of a CH{sub 3}NH{sub 3}PbI{sub 3} hydrate phase by H{sub 2}O incorporation. In particular, rapid phase change occurs in the near-surface region and the CH{sub 3}NH{sub 3}PbI{sub 3} layer thickness reduces rapidly in the initial 1 h air exposure even at a low relative humidity of 40%. After the prolonged air exposure, the CH{sub 3}NH{sub 3}PbI{sub 3} layer is converted completely to hexagonal platelet PbI{sub 2}/hydrate crystals that have a distinct atomic-scale multilayer structure with a period of 0.65 ± 0.05 nm. We find that conventional x-ray diffraction and optical characterization in the visible region, used commonly in earlier works, are quite insensitive to the surface phase change. Based on results obtained in this work, we discuss the degradation mechanism of CH{sub 3}NH{sub 3}PbI{sub 3} in humid air.
Evaluate humidity sensing properties of novel TiO{sub 2}–WO{sub 3} composite material

Energy Technology Data Exchange (ETDEWEB)

Lin, Wang-De [Department of Applied Chemistry, Providence University, Taichung 43301 Taiwan, ROC (China); Department of Center for General Education, St. Mary' s Junior College of Medicine, Nursing and Management, Yilan 26644 Taiwan, ROC (China); Lai, De-Sheng; Chen, Min-Hung [Department of Applied Chemistry, Providence University, Taichung 43301 Taiwan, ROC (China); Wu, Ren-Jang, E-mail: rjwu@pu.edu.tw [Department of Applied Chemistry, Providence University, Taichung 43301 Taiwan, ROC (China); Chen, Fu-Chou [Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan, ROC (China)

2013-10-15

Graphical abstract: TiO{sub 2}–WO{sub 3} (1:1) showed better humidity sensing properties than others within the range of 12–90% relative humidity (RH), the response and recovery time were about 20 s and 160 s, respectively. Compared to the previous studies, the prepared sensor exhibits higher sensitivity (S = 451) and the low hysteresis value was around 0.13% at 32% RH. - Highlights: • Novel TiO{sub 2}–WO{sub 3} composite material was prepared for humidity sensor. • The sensor exhibits higher sensitivity (S = 451). • Low hysteresis value was around 0.13% at 32% RH. - Abstract: A novel TiO{sub 2}–WO{sub 3} composite material was prepared using a different proportion of TiO{sub 2} and WO{sub 3} to that investigated in previous studies. The obtained mesoporous material was characterized using X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and N{sub 2} adsorption-desorption techniques. The humidity-sensing properties were measured using an inductance, capacitance and resistance analyzer. The results demonstrated that the TiO{sub 2}–WO{sub 3} sample with a ratio of 1:1 showed better humidity sensing properties. Compared to previous studies, the prepared sensor exhibited higher sensitivity (S = 451) and the lower hysteresis value was around 0.13% at 32% RH. Complex impedance analysis indicated that the enhanced humidity sensitivity was probably due to spherical Brunauer–Emmett–Teller surface area and the hetero-junction between TiO{sub 2}–WO{sub 3} thin films, while the impedance varied about three orders of magnitude. Our results demonstrated the potential application of TiO{sub 2}–WO{sub 3} composite for fabricating high performance humidity sensors.
Restoration of soil fertility and improvement of cropping systems for sustainable development in the humid savannahs of Cote d'Ivoire

International Nuclear Information System (INIS)

Bachmann, T.

1999-01-01

The present FAO-project addresses the soil fertility problems by combining organic with inorganic nutrient sources and actively involving farmers and other beneficiaries in an integrated, long-term development process. A major objective of the project is the participatory on-farm testing and validation of available technological innovations for soil fertility improvement. The results should fulfill two main requirements: (i) provide the farmer with a short-term production increase and (ii) improve/maintain soil fertility in the medium and long-term. The strategic framework of the project is based on the following three main elements: the need to take into account all aspects of soil fertility restoration including areas concerned, cost of fertility restoration, and economic profitability and sustainability; - the need to test all fertility improving measures at farm level in representative agro-ecozones of the humid and sub-humid savannas before their extension at large; the need to identify major macro-economic constraints (e.g. marketing) which impede sustainable agricultural development in the savannah region. The primary goal of the project is to replace traditional shifting cultivation in the humid savannas of the country by economically, ecologically and socially more sustainable production systems. In order to achieve this development objective the project focuses on the following main issues: restoration of soil fertility through improved land and crop management and more efficient use of mineral and organic fertilizers; crop diversification through more efficient use of water resources (irrigation); introduction of new cropping systems which have been successfully tested in countries with similar agro-ecological conditions; adapting traditional land tenure to the market economy; involving the private sector in all aspects of regional development assisted by Government through the creation of a favorable environment. Phase 1: constraint analysis and
MoS{sub 2}-modified ZnO quantum dots nanocomposite: Synthesis and ultrafast humidity response

Energy Technology Data Exchange (ETDEWEB)

Ze, Lu [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Yueqiu, Gong, E-mail: yqgong@xtu.edu.cn [School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China); Xujun, Li; Yong, Zhang [School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105 (China)

2017-03-31

Highlights: • MoS{sub 2}@ZnO QDs composite structure was synthesized by two-steps methods. • Ultrafast humidity sensing response is achieved by MoS{sub 2}@ZnO QDs humidity sensor. • Sensor performs excellent cycle stability from 11% to 95% RH. • Humidity sensor could detect wide humidity range (11–95%). - Abstract: In this work, ZnO quantum dots (QDs), layered MoS{sub 2} and MoS{sub 2}-modified ZnO QDs (MoS{sub 2}@ZnO QDs) nanocomposite were synthesized and then applied as humidity sensor. The crystal structure, morphology and element distribution of ZnO QDs, MoS{sub 2} and MoS{sub 2}@ZnO QDs were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectrometry, respectively. The humidity sensing characteristics of the MoS{sub 2} and MoS{sub 2}@ZnO QDs against various relative humidity were measured at room temperature. The results show that the MoS{sub 2}@ZnO QDs sensor exhibits high sensitivity with an impedance variation of three or four orders of magnitude to relative humidity range of 11–95% and it exhibits a short response-recovery time (1 s for adsorption and 20 s for desorption) and excellent repeatability. The mechanisms of the excellent performance for humidity sensing of MoS{sub 2}@ZnO QDs sensor were discussed based on its impedance properties. Our work could offer guidelines to design higher performance especially ultrafast humidity response sensor utilizing the nanocomposite structure with two dimensional material and QDs.
N{sub 2}O Emission from energy crop fields

Energy Technology Data Exchange (ETDEWEB)

Joergensen, B.J. [The Royal Veterinary and Agricultural Univ., Dept. of Agricultural Sciences, Section of Soil, Water and Plant Nutrition (Denmark); Nyholm Joergensen, R. [Research Centre Foulum, The Danish Inst. of Plant and Soil Science, Dept. of Soil Science (Denmark)

1996-03-01

The interest in N{sub 2}O emissions from soils with energy crops is a results of its properties as a greenhouse gas, since the global warming potential of N{sub 2}O per unit mass is about 320 times greater than CO{sub 2}. The contribution of N{sub 2}O from the soil to the atmosphere may increase due to agricultural management. Consequently, large N{sub 2}O emissions can lower the reduction of the greenhouse effect achieved by the substitution of fossil fuels by energy crops. For this reason it is crucial to find the crops for combustion with the lowest potential for emission of N{sub 2}O from the soil per produced energy unit. The aims of this study were to assess the annual N{sub 2}O flux from a Miscanthus 'Giganteus' (M. 'Giganteus') and winter rye (Secale cereale) field, and to investigate the factors affecting the N{sub 2}O emission. To obtain these aims a method was developed for measurements in tall crops. The thesis contains a literature review on the N{sub 2}O emission from the soils, a section with development of the technique for N{sub 2}O flux measurements, and an experimental section. Finally, the thesis contains a section where the results are discussed in relation to the use of energy crops. In all the filed studies, the N{sub 2}O emission was measured by using a new developed closed-chamber technique. The main advantages of the chamber method were the ability to contain growing plants up to a height of 3 m, and the relatively large area (2X2m) covered by each other. Soils with annual and perennial crops can be expected to emit less then 3 kg N{sub 2}O ha{sup -1} yr{sup -1}. This amount corresponds to 960 kg CO{sub 2} ha{sup -1} yr{sup -1} compared to a total CO{sub 2} reduction of 10 to 19 tons CO{sub 2} ha{sup -1} yr{sup -1} using the energy crops as substitution for fossil fuels. An efficient way to reduce the N{sub 2}O emission is to exclude use of fertiliser but this also reduces the dry matter yield and consequently also the
N{sub 2}O Emission from energy crop fields

Energy Technology Data Exchange (ETDEWEB)

Joergensen, B.J. [The Royal Veterinary and Agricultural Univ., Dept. of Agricultural Sciences, Section of Soil, Water and Plant Nutrition (Denmark); Nyholm Joergensen, R. [Research Centre Foulum, The Danish Inst. of Plant and Soil Science, Dept. of Soil Science (Denmark)

1996-03-01

The interest in N{sub 2}O emissions from soils with energy crops is a results of its properties as a greenhouse gas, since the global warming potential of N{sub 2}O per unit mass is about 320 times greater than CO{sub 2}. The contribution of N{sub 2}O from the soil to the atmosphere may increase due to agricultural management. Consequently, large N{sub 2}O emissions can lower the reduction of the greenhouse effect achieved by the substitution of fossil fuels by energy crops. For this reason it is crucial to find the crops for combustion with the lowest potential for emission of N{sub 2}O from the soil per produced energy unit. The aims of this study were to assess the annual N{sub 2}O flux from a Miscanthus `Giganteus` (M. `Giganteus`) and winter rye (Secale cereale) field, and to investigate the factors affecting the N{sub 2}O emission. To obtain these aims a method was developed for measurements in tall crops. The thesis contains a literature review on the N{sub 2}O emission from the soils, a section with development of the technique for N{sub 2}O flux measurements, and an experimental section. Finally, the thesis contains a section where the results are discussed in relation to the use of energy crops. In all the filed studies, the N{sub 2}O emission was measured by using a new developed closed-chamber technique. The main advantages of the chamber method were the ability to contain growing plants up to a height of 3 m, and the relatively large area (2X2m) covered by each other. Soils with annual and perennial crops can be expected to emit less then 3 kg N{sub 2}O ha{sup -1} yr{sup -1}. This amount corresponds to 960 kg CO{sub 2} ha{sup -1} yr{sup -1} compared to a total CO{sub 2} reduction of 10 to 19 tons CO{sub 2} ha{sup -1} yr{sup -1} using the energy crops as substituion for fossil fuels. An efficient way to reduce the N{sub 2}O emission is to exclude use of fertiliser but this also reduces the dry matter yield and consequently also the CO{sub 2} reduction
The effects of increasing CO sub 2 on crop photosynthesis and productivity: a review of field studies

Energy Technology Data Exchange (ETDEWEB)

Lawlor, D.W.; Mitchell, R.A.C. (Institute of Arable Crops Research, Harpenden (UK). Biochemistry and Physiology Dept.)

1991-10-01

Only a small proportion of elevated CO{sub 2} studies on crops have taken place in the field. They generally confirm results obtained in controlled environments: CO{sub 2} increases photosynthesis, dry matter production and yield, substantially in C{sub 3} species, but less in C{sub 4}, it decreases stomatal conductance and transpiration in C{sub 3} and C{sub 4} species and greatly improves water-use efficiency in all plants. The increased productivity of crops with CO{sub 2} enrichment is also related to the greater leaf area produced. Stimulation of yield is due more to an increase in the number of yield-forming structures than in their size. There is little evidence of a consistent effect of CO{sub 2} on partitioning of dry matter between organs or on their chemical composition, except for tubers. Work has concentrated on a few crops (largely soybean) and more is needed on crops for which there are few data (e.g. rice). Field studies on the effects of elevated CO{sub 2} in combination with temperature, water and nutrition are essential; they should be related to the development and improvement of mechanistic crop models, and designed to test their predictions. 70 refs., 2 tabs.
Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis.

Science.gov (United States)

Fatnassi, Hicham; Pizzol, Jeannine; Senoussi, Rachid; Biondi, Antonio; Desneux, Nicolas; Poncet, Christine; Boulard, Thierry

2015-01-01

Frankliniella occidentalis (Pergande) is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity) and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i) the air temperature and air humidity were very heterogeneously distributed within the crop, (ii) pest populations aggregated in the most favourable climatic areas and (iii) the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest.
Within-Crop Air Temperature and Humidity Outcomes on Spatio-Temporal Distribution of the Key Rose Pest Frankliniella occidentalis.

Directory of Open Access Journals (Sweden)

Hicham Fatnassi

Full Text Available Frankliniella occidentalis (Pergande is a key pest of various crops worldwide. In this study, we analyse the dependence of the infestation of this pest on spatially distributed micro climatic factors in a rose greenhouse. Despite the importance of this subject, the few existing studies have been realized in laboratory rather than in greenhouse conditions. However, recent progress on greenhouse microclimate characterisation has highlighted the strong indoor climate heterogeneity that may influence the within-crop pest distribution. In this study, both microclimate (air temperature and humidity and thrips distribution were simultaneously mapped in a rose greenhouse. The measurements were sensed in a horizontal plane situated at mid-height of the rose crop inside the greenhouse. Simultaneously, thrips population dynamics were assessed after an artificial and homogeneous infestation of the rose crop. The spatio-temporal distribution of climate and thrips within the greenhouse were compared, and links between thrips infestation and climatic conditions were investigated. A statistical model was used to define the favourable climate conditions for thrips adults and larvae. Our results showed that (i the air temperature and air humidity were very heterogeneously distributed within the crop, (ii pest populations aggregated in the most favourable climatic areas and (iii the highest population density of thrips adults and larvae were recorded at 27°C and 22°C for temperature and 63% and 86% for humidity, respectively. These findings confirm, in real rose cropping conditions, previous laboratory studies on the F. occidentalis climatic optimum and provide a solid scientific support for climatic-based control methods against this pest.
Nanoscale mechanochemical wear of phosphate laser glass against a CeO{sub 2} particle in humid air

Energy Technology Data Exchange (ETDEWEB)

Yu, Jiaxin, E-mail: yujiaxin@swust.edu.cn [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); He, Hongtu; Zhang, Yafeng [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); Hu, Hailong [Analysis and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China)

2017-01-15

Highlights: • Friction components of phosphate glass/CeO{sub 2} pair in humid air were quantified to understand the friction mechanism. • Severe nanoscale wear was directly observed by AFM topography on both phosphate glass and CeO{sub 2} particle in humid air. • The wearless behaviors of phosphate glass in vacuum were confirmed by the AFM phase image. • Capillary water bridge induced corrosion plays an important role in the mechanochemical wear of phosphate glass in air. - Abstract: Using an atomic force microscope, the friction and wear of phosphate laser glass against a CeO{sub 2} particle were quantitatively studied both in humid air and in vacuum, to reveal the water molecules induced mechanochemical wear mechanism of phosphate laser glass. The friction coefficient of the glass/CeO{sub 2} pair in air was found to be 5–7 times higher than that in vacuum due to the formation of a capillary water bridge at the friction interface, with a contribution of the capillary-related friction to the total friction coefficient as high as 65–79%. The capillary water bridge further induced a serious material removal of glass and CeO{sub 2} particle surfaces, while supplying both a local liquid water environment to corrode the glass surface and a high shearing force to assist the stretching of the Ce−O−P bond, accelerating the reaction between water and the glass/CeO{sub 2} pair. In vacuum, however, no discernable wear phenomena were observed, but the phase images captured by AFM tapping mode suggested the occurrence of potential strain hardening in the friction area of the glass surface.
Effects of temporal changes in climate variables on crop production ...

African Journals Online (AJOL)

Climate variability and change have been implicated to have significant impacts on global and regional food production particularly the common stable food crops performance in tropical sub-humid climatic zone. However, the extent and nature of these impacts still remain uncertain. In this study, records of crop yields and ...
Relative Humidity and the Susceptibility of Austenitic Stainless Steel to Stress Corrosion Cracking in an impure Plutonium Oxide Environment

Energy Technology Data Exchange (ETDEWEB)

Zapp, P.; Duffey, J.; Lam, P.; Dunn, K.

2010-05-05

Laboratory tests to investigate the corrosivity of moist plutonium oxide/chloride salt mixtures on 304L and 316L stainless steel coupons showed that corrosion occurred in selected samples. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The exposures were conducted in sealed containers in which the oxide-salt mixtures were loaded with about 0.6 wt % water from a humidified helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration, the composition of the salt and the moisture present in the test environment. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride and 0.6 wt% water. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas above the solid mixture, or in coupons exposed to other mixtures with either no CaCl{sub 2} or 0.92 wt% CaCl{sub 2}. SCC was present where the 0.6 wt % water content exceeded the value needed to fully hydrate the available CaCl{sub 2}, but was absent where the water content was insufficient. These results reveal the significance of the relative humidity in the austenitic stainless steels environment to their susceptibility to corrosion. The relative humidity in the test environment was controlled by the water loading and the concentration of the hydrating salts such as CaCl{sub 2}. For each salt or salt mixture there is a threshold
Herbaceous energy crops in humid lower South USA

Energy Technology Data Exchange (ETDEWEB)

Prine, G.M.; Woodard, K.R. [Univ. of Florida, Gainesville, FL (United States)

1993-12-31

The humid lower South has the long warm growing season and high rainfall conditions needed for producing high-yielding perennial herbaceous grasses and shrubs. Many potential biomass plants were evaluated during a ten-year period. Perennial tall grasses such as elephantgrass (Pennisetum purpureum), sugarcane and energycane (Saccharum spp.) and the leguminous shrub Leucaena leucocephala were the highest in biomass production. These perennial crops often have top growth killed by winter freezes and regenerate from underground parts. The tall grasses have high yields because of linear crop growth rates of 18 to 27 g m{sup 2} d{sup {minus}1} for long periods (140 to 196 d) each season. Tall grasses must be planted vegetatively, which is more costly than seed propagation, however, once established, they may persist for many seasons. Oven dry biomass yields have varied from 20 to 45 Mg ha{sup {minus}1} yr{sup {minus}1} in colder subtropical to mild temperate locations to over 60 Mg ha{sup {minus}1} yr{sup {minus}1} in the lower portion of the Florida peninsular. Highest biomass yields have been produced when irrigated with sewage effluent or when grown on phosphatic clay and muck soils in south Florida. The energy content of 1 Mg of oven dry tall grass and leucaena is equivalent to that of about 112 and 123 gallons of number 2 diesel fuel, respectively.

Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles for humidity sensor

Energy Technology Data Exchange (ETDEWEB)

Toloman, D. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Popa, A., E-mail: popa@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Stan, M.; Socaci, C.; Biris, A.R. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj-Napoca (Romania); Katona, G. [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos Street, 400028 Cluj-Napoca (Romania); Tudorache, F. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Petrila, I. [Interdisciplinary Research Department – Field Science & RAMTECH, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania); Faculty of Automatic Control and Computer Engineering, Gheorghe Asachi Technical University, 27 Dimitrie Mangeron Street, 700050 Iasi (Romania); Iacomi, F. [Faculty of Physics, Al. I. Cuza University, 11 Carol I Blvd., 7000506 Iasi (Romania)

2017-04-30

Highlights: • Reduced graphene oxide decorated with Fe doped SnO{sub 2} nanoparticles were synthesized. • The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM. • The reduction of graphene oxide was evidenced using XRD and FT-IR. • Sensitivity tests for relative humidity (RH) were carried out. • The composite sensor exhibited enhanced sensing response as compared with Fe:SnO{sub 2}. - Abstract: Reduced graphene oxide (rGO) decorated with Fe doped SnO{sub 2} nanoparticles were fabricated via the electrostatic interaction between positively charged modified Fe-doped SnO{sub 2} oxide and negatively charged graphene oxide (GO) in the presence of poly(allylamine) hydrochloride (PAH). The decoration of rGO layers with SnO{sub 2}:Fe nanoparticles was highlited by TEM microsopy. For composite sample the diffraction patterns coincide well with those of SnO{sub 2}:Fe nanoparticles. The reduction of graphene oxide was evidenced using XRD and FT-IR spectroscopy. The formation of SnO{sub 2}:Fe-PAH-graphene composites was confirmed by FT-IR, Raman and EPR spectroscopy. Sensitivity tests for relative humidity (RH) measurements were carried out at five different concentrations of humid air at room temperature. The prepared composite sensor exhibited a higher sensing response as compared with Fe:SnO{sub 2} nanoparticles.
Yield, Phenotypical Stability and Micronutrients Contents in the Biofortified Bean in the Colombian Sub-humid Caribbean

Directory of Open Access Journals (Sweden)

Adriana Patricia Tofiño-Rivera,

2016-09-01

Full Text Available The intake of protein and micronutrients in the Colombian sub-humid Caribbean has been a concern in recent years. About 57 % of the population in the sub-humid Caribbean region, has a deficit of amino acids —iron (Fe and zinc (Zn— in their diet. This study shows the results of the agronomic evaluation of the performance and quality of nine genotypes of biofortified bean and one local control in four environments of Cesar. The methodology included chemical and microbio-logical soil characterization, reaction evaluation to pests and diseases, multi-sited valuation by AMMI and selection of two varieties with better yield and nutritional content by ACP. In addition to these two prioritized genotypes, the Pearson correlation coefficient between seed micronutrient content for locations and years was determined. The biofortified genotypes surpassed the control group significantly in both yield and precocity. According to the ACP, the biofortified group differed from the control group in iron and zinc content in the seed, confirming its superior characteristics in nutritional quality, and resistance to pests and diseases. The AMMI showed that the genotype SMR43 reflected stability and predi-ctability between environments and SMR39 had specific adaptation in the best location for grain production. Both genotypes retained high levels of micronutrients between locations and years as according to the Pearson correlation.
Performance limit of daytime radiative cooling in warm humid environment

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Takahiro Suichi

2018-05-01

Full Text Available Daytime radiative cooling potentially offers efficient passive cooling, but the performance is naturally limited by the environment, such as the ambient temperature and humidity. Here, we investigate the performance limit of daytime radiative cooling under warm and humid conditions in Okayama, Japan. A cooling device, consisting of alternating layers of SiO2 and poly(methyl methacrylate on an Al mirror, is fabricated and characterized to demonstrate a high reflectance for sunlight and a selective thermal radiation in the mid-infrared region. In the temperature measurement under the sunlight irradiation, the device shows 3.4 °C cooler than a bare Al mirror, but 2.8 °C warmer than the ambient of 35 °C. The corresponding numerical analyses reveal that the atmospheric window in λ = 16 ∼ 25 μm is closed due to a high humidity, thereby limiting the net emission power of the device. Our study on the humidity influence on the cooling performance provides a general guide line of how one can achieve practical passive cooling in a warm humid environment.
Environmental Sustainability of Some Cropping Systems in the ...

African Journals Online (AJOL)

Results from most findings reviewed in this paper had shown that there was no one size fits cropping system that can be use for sustainability of the humid environment but the best approach was the diversification of both traditional and modern cropping systems. The transition to systems which are both sustainable and ...
Modelling soil moisture under different land covers in a sub-humid ...

Indian Academy of Sciences (India)

in the sub-humid climate within the Western Ghats, Karnataka, India. ... carried out with respect to the water-holding capacity of the soils with the aim of explaining ... changes have taken place in the land-use/cover of ... about 20–25 km inland.
An Inexpensive, Stable, and Accurate Relative Humidity Measurement Method for Challenging Environments.

Science.gov (United States)

Zhang, Wei; Ma, Hong; Yang, Simon X

2016-03-18

In this research, an improved psychrometer is developed to solve practical issues arising in the relative humidity measurement of challenging drying environments for meat manufacturing in agricultural and agri-food industries. The design in this research focused on the structure of the improved psychrometer, signal conversion, and calculation methods. The experimental results showed the effect of varying psychrometer structure on relative humidity measurement accuracy. An industrial application to dry-cured meat products demonstrated the effective performance of the improved psychrometer being used as a relative humidity measurement sensor in meat-drying rooms. In a drying environment for meat manufacturing, the achieved measurement accuracy for relative humidity using the improved psychrometer was ±0.6%. The system test results showed that the improved psychrometer can provide reliable and long-term stable relative humidity measurements with high accuracy in the drying system of meat products.
Studies on the injuries of crops by harmful gases under covering. I. Injuries of vegetables by gaseous nitrogen dioxide and the conditions affecting crop susceptibility. [Eggplant

Energy Technology Data Exchange (ETDEWEB)

Kato, T; Tachibana, S; Inden, T

1974-09-01

The effects of environmental conditions such as soil-moisture humidity, and light on injuries to crops such as kidney bean, cucumber, tomato, and egg plant as well as the relationships between injury occurrence and plant nutrition, age of seedlings, and leaf position were investigated when the crops were exposed to gaseous nitrogen dioxide under a covering. The injury was severer when the soil moisture was richer and the humidity was higher. Injury was greater under dark conditions as opposed to light conditions before, during, and after NO/sub 2/ exposure. The first leaves of kidney bean plants were more susceptible to the gas when they were younger. Leaves with active metabolism (in the middle position) were the most susceptible to NO/sub 2/. Vegetables grown in fields or cultures poor in nitrogen were apparently susceptible to the gas, and those grown in ammonia-nitrogen rich cultures were more severely injured than those grown on nitrate-nitrogen rich cultures. Those grown in iron-deficient cultures were more susceptible to NO/sub 2/ than controls.
Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate{sub N} simulation model

Energy Technology Data Exchange (ETDEWEB)

Guo Ruiying [Ministry of Education Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, No. 222 Tianshui Nanlu, Lanzhou 730000, Gansu Province (China); Nendel, Claas, E-mail: nendel@zalf.d [Institute for Landscape Systems Analysis, Leibniz-Center for Agricultural Landscape Research, Eberswalder Strasse 84, 15374 Muencheberg (Germany); Rahn, Clive [Warwick HRI, Wellesbourne CV35 9EF (United Kingdom); Jiang Chunguang; Chen Qing [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing 100193 (China)

2010-06-15

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate{sub N} simulation model. EU-Rotate{sub N} was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter. - The EU-Rotate{sub N} model can satisfactorily simulate crop N uptake and N{sub min} dynamics in a typical greenhouse cucumber production system of North China
Ceramic thick film humidity sensor based on MgTiO{sub 3} + LiF

Energy Technology Data Exchange (ETDEWEB)

Kassas, Ahmad, E-mail: a.kassas.mcema@ul.edu.lb [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Bernard, Jérôme; Lelièvre, Céline; Besq, Anthony; Guhel, Yannick; Houivet, David; Boudart, Bertrand [Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Lakiss, Hassan [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Faculty of Engineering, Section III, Hariri Campus, Hadath, Beirut (Lebanon); Hamieh, Tayssir [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon)

2013-10-15

Graphical abstract: - Highlights: • The fabricated sensor based on MgTiO{sub 3} + LiF materials used the spin coating technology. • The response time is 70 s to detect variation between 5 and 95% relative humidity. • The addition of Scleroglucan controls the viscosity and decreases the roughness of thick film surface. • This humidity sensor is a promising, low-cost, high-quality, reliable ceramic films, that is highly sensitive to humidity. - Abstract: The feasibility of humidity sensor, consisting of a thick layer of MgTiO{sub 3}/LiF materials on alumina substrate, was studied. The thermal analysis TGA-DTGA and dilatometric analysis worked out to confirm the sintering temperature. An experimental plan was applied to describe the effects of different parameters in the development of the thick film sensor. Structural and microstructural characterizations of the developed thick film were made. Rheological study with different amounts of a thickener (scleroglucan “sclg”), showing the behavior variation, as a function of sclg weight % was illustrated and rapprochement with the results of thickness variation as a function of angular velocity applied in the spin coater. The electrical and dielectric measurements confirmed the sensitivity of the elaborated thick film against moisture, along with low response time.
Cowpea: a legume crop for a challenging environment.

Science.gov (United States)

Carvalho, Márcia; Lino-Neto, Teresa; Rosa, Eduardo; Carnide, Valdemar

2017-10-01

Cowpea is a grain legume native from Africa and is a primary source of protein for millions of people in sub-Saharan Africa and other parts of the developing world. The main important characteristics of this crop include a good protein quality with a high nutritional value, its nitrogen-fixing ability, and an ability to be more drought- and heat-tolerant than most of its legume relatives. In a research perspective, studies of cowpea are relatively scarce, despite its relevance to agriculture in the developing world and its resilience to stress. The present review provides an overview of different aspects of cowpea, with a special emphasis on the molecular markers for assessing genetic diversity, as well as on biochemical and transcriptomic data with respect to evaluating cowpea drought stress tolerance. The integration of both datasets will be useful for the improvement of cowpea because research on drought stress tolerance is of major interest for this crop in a challenging environment. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
An Assessment of some Fertilizer Recommendations under Different Cropping Systems in a Humid Tropical Environment

Directory of Open Access Journals (Sweden)

Fondufe, EY.

2001-01-01

Full Text Available Studies were carried out to determine the effects of four fertilizer recommendation systems (bianket recommendation, soil test recommendation, recommendation based on nutrient supplementation index and unfertilized control on five cropping systems (sole cassava, maize, melon, cassava + maize and cassava + maize + melon. The experiment was a split-plot in randomised complete block design, with fertilizer recommendation systems in main plots and cropping systems in subplots. Observations were made on plant growth and yield. Plant samples were also analyzed for N, P and K uptake. Cassava and melon gave higher yields in sole cropping than intercropping while maize yield under intercropping exceeded that under sole cropping by 17 %. Cassava root yield was significantly reduced by 24 and 35 % in cassava + maize and cassava + maize + melon plots. Fertilizer recommendation based on nutrient supplementation index (NSI gave the highest crop yield 41, 31, and 27 t/ha of maize in sole maize, maize + cassava and maize + cassava + melon and 0.6 and 0.2 t/ha of sole melon and intercropped melon respectively. Nitrogen uptake by cassava and maize was highest under NSI, but fertilizer recommendation based on soil test gave the highest crop yield and monetary returns per unit of fertilizer used.
SO/sub 2/ dose-response sensitivity classification data for crops and natural vegetation species

Energy Technology Data Exchange (ETDEWEB)

Irving, P.M.; Ballou, S.W.

1980-09-01

Over the past several years studies have been made on the interaction of sulfur dioxide (SO/sub 2/) and vegetation by performing field research and by developing analytical procedures for applying field observation data to energy impact assessments. As a result of this work, numerous reports have been prepared on crop-pollutant interactions, such as dose-response data; on the applications of such data to screening approaches for identifying crops at risk; and on models that predict crop yield reductions from point source emissions of SO/sub 2/. Data that were used for these studies, such as the crop-at-risk screening procedure, are presented in this report. Maps are also presented that show the national distribution of SO/sub 2/-sensitive crops and natural vegetation.
Injury Profile SIMulator, a qualitative aggregative modelling framework to predict crop injury profile as a function of cropping practices, and the abiotic and biotic environment. I. Conceptual bases.

Directory of Open Access Journals (Sweden)

Jean-Noël Aubertot

Full Text Available The limitation of damage caused by pests (plant pathogens, weeds, and animal pests in any agricultural crop requires integrated management strategies. Although significant efforts have been made to i develop, and to a lesser extent ii combine genetic, biological, cultural, physical and chemical control methods in Integrated Pest Management (IPM strategies (vertical integration, there is a need for tools to help manage Injury Profiles (horizontal integration. Farmers design cropping systems according to their goals, knowledge, cognition and perception of socio-economic and technological drivers as well as their physical, biological, and chemical environment. In return, a given cropping system, in a given production situation will exhibit a unique injury profile, defined as a dynamic vector of the main injuries affecting the crop. This simple description of agroecosystems has been used to develop IPSIM (Injury Profile SIMulator, a modelling framework to predict injury profiles as a function of cropping practices, abiotic and biotic environment. Due to the tremendous complexity of agroecosystems, a simple holistic aggregative approach was chosen instead of attempting to couple detailed models. This paper describes the conceptual bases of IPSIM, an aggregative hierarchical framework and a method to help specify IPSIM for a given crop. A companion paper presents a proof of concept of the proposed approach for a single disease of a major crop (eyespot on wheat. In the future, IPSIM could be used as a tool to help design ex-ante IPM strategies at the field scale if coupled with a damage sub-model, and a multicriteria sub-model that assesses the social, environmental, and economic performances of simulated agroecosystems. In addition, IPSIM could also be used to help make diagnoses on commercial fields. It is important to point out that the presented concepts are not crop- or pest-specific and that IPSIM can be used on any crop.
Injury Profile SIMulator, a qualitative aggregative modelling framework to predict crop injury profile as a function of cropping practices, and the abiotic and biotic environment. I. Conceptual bases.

Science.gov (United States)

Aubertot, Jean-Noël; Robin, Marie-Hélène

2013-01-01

The limitation of damage caused by pests (plant pathogens, weeds, and animal pests) in any agricultural crop requires integrated management strategies. Although significant efforts have been made to i) develop, and to a lesser extent ii) combine genetic, biological, cultural, physical and chemical control methods in Integrated Pest Management (IPM) strategies (vertical integration), there is a need for tools to help manage Injury Profiles (horizontal integration). Farmers design cropping systems according to their goals, knowledge, cognition and perception of socio-economic and technological drivers as well as their physical, biological, and chemical environment. In return, a given cropping system, in a given production situation will exhibit a unique injury profile, defined as a dynamic vector of the main injuries affecting the crop. This simple description of agroecosystems has been used to develop IPSIM (Injury Profile SIMulator), a modelling framework to predict injury profiles as a function of cropping practices, abiotic and biotic environment. Due to the tremendous complexity of agroecosystems, a simple holistic aggregative approach was chosen instead of attempting to couple detailed models. This paper describes the conceptual bases of IPSIM, an aggregative hierarchical framework and a method to help specify IPSIM for a given crop. A companion paper presents a proof of concept of the proposed approach for a single disease of a major crop (eyespot on wheat). In the future, IPSIM could be used as a tool to help design ex-ante IPM strategies at the field scale if coupled with a damage sub-model, and a multicriteria sub-model that assesses the social, environmental, and economic performances of simulated agroecosystems. In addition, IPSIM could also be used to help make diagnoses on commercial fields. It is important to point out that the presented concepts are not crop- or pest-specific and that IPSIM can be used on any crop.
Cover crop biomass production and water use in the central great plains under varying water availability

Science.gov (United States)

The water-limited environment of the semi-arid central Great Plains may not have potential to produce enough cover crop biomass to generate benefits associated with cover crop use in more humid regions. There have been reports that cover crops grown in mixtures produce more biomass with greater wate...
Synthesis of γ-WO{sub 3} thin films by hot wire-CVD and investigation of its humidity sensing properties

Energy Technology Data Exchange (ETDEWEB)

Jadkar, Vijaya; Waykar, Ravindra; Jadhavar, Ashok [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Pawbake, Amit [School of Energy Studies, Savitribai Phule Pune University, Pune 411 007 (India); Physical and Material Chemistry Division, National Chemical Laboratory, Pune 411 008 (India); Date, Abhijit [School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Plenty Road, Bundoora, Melbourne VIC 3083 (Australia); Late, Dattatray [Physical and Material Chemistry Division, National Chemical Laboratory, Pune 411 008 (India); Pathan, Habib; Gosavi, Suresh; Jadkar, Sandesh [Department of Physics, Savitribai Phule Pune University, Pune 411 007 (India)

2017-05-15

In this study, monoclinic tungsten oxide (γ-WO{sub 3}) have been grown in a single step using HW-CVD method by resistively heating W filaments in a constant O{sub 2} pressure. The formation of γ-WO{sub 3} was confirmed using low angle-XRD and Raman spectroscopy analysis. Low angle-XRD analysis revealed that as-deposited WO{sub 3} film are highly crystalline and the crystallites have preferred orientation along the (002) direction. HRTEM analysis and SAED pattern also show the highly crystalline nature of WO{sub 3} with d spacing of ∝ 0.38 nm, having an orientation along the (002) direction. Surface topography investigated by SEM analysis shows the formation of a uniform and homogeneous cauliflower like morphology throughout the substrate surface without flaws and cracks. A humidity sensing device incorporating WO{sub 3} is also fabricated, which shows a maximum humidity sensitivity factor of ∝ 3954% along with a response time of ∝14 s and a recovery time of ∝25 s. The obtained results demonstrate that it is possible to synthesize WO{sub 3} in a single step by HW-CVD method and to fabricate a humidity sensor by using it. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Study on radon concentration monitoring using activated charcoal canisters in high humidity environments

International Nuclear Information System (INIS)

Wang Yuexing; Wang Haijun; Yang Yifang; Qin Sichang; Wang Zhentao; Zhang Zhenjiang

2009-01-01

The effects of humidity on the sensitivity using activated charcoal canisters for measuring radon concentrations in high humidity environments were studied. Every canister filled with 80 g of activated charcoal, and they were exposed to 48 h or 72 h in the relative humidity of 68%, 80%, 88% and 96% (28 degree C), respectively. The amount of radon absorbed in the canisters was determined by counting the gamma rays from 214 Pb and 214 Bi (radon progeny). The results showed that counts decreased with the increase of relative humidity. There was a negative linear relationship between count and humidity. In the relative humidity range of 68%-96%, the sensitivity of radon absorption decreased about 2.4% for every 1% (degree)rise in humidity. The results also showed that the exposure time of the activated charcoal canisters should be less than 3 days. (authors)
Irrigation water consumption modelling of a soilless cucumber crop under specific greenhouse conditions in a humid tropical climate

Directory of Open Access Journals (Sweden)

Galo Alberto Salcedo

Full Text Available ABSTRACT: The irrigation water consumption of a soilless cucumber crop under greenhouse conditions in a humid tropical climate has been evaluated in this paper in order to improve the irrigation water and fertilizers management in these specific conditions. For this purpose, a field experiment was conducted. Two trials were carried out during the years 2011 and 2014 in an experimental farm located in Vinces (Ecuador. In each trial, the complete growing cycle of a cucumber crop grown under a greenhouse was evaluated. Crop development was monitored and a good fit to a sigmoidal Gompertz type growth function was reported. The daily water uptake of the crop was measured and related to the most relevant indoor climate variables. Two different combination methods, namely the Penman-Monteith equation and the Baille equation, were applied. However, the results obtained with these combination methods were not satisfactory due to the poor correlation between the climatic variables, especially the incoming radiation, and the crop's water uptake (WU. On contrary, a good correlation was reported between the crop's water uptake and the leaf area index (LAI, especially in the initial crop stages. However, when the crop is fully developed, the WU stabilizes and becomes independent from the LAI. A preliminary model to simulate the water uptake of the crop was adjusted using the data obtained in the first experiment and then validated with the data of the second experiment.
Impacts of enhanced fertilizer applications on tropospheric ozone and crop damage over sub-Saharan Africa

Science.gov (United States)

Huang, Yaoxian; Hickman, Jonathan E.; Wu, Shiliang

2018-05-01

Fertilizer-induced nitrogen oxides (NOx) emissions in sub-Saharan Africa are expected to increase substantially in the coming decades, driven by increasing application of fertilizers to increase crop yields in an effort to attain food security across the continent. In many parts of sub-Saharan Africa, surface ozone (O3) is sensitive to increasing atmospheric concentrations of NOx. In this study, we employ the GEOS-Chem chemical transport model to conduct a preliminary investigation of the impacts on O3 air quality and the consequential crop damage associated with increasing fertilizer-induced NOx emissions in sub-Saharan Africa. Our simulation results, constrained by field NO flux measurements for the years 2011 and 2012 in response to a variety of fertilizer application rates in western Kenya, show that the enhancements in NO flux with fertilizer application rate of 150 kg N ha-1 can increase surface NOx and O3 concentrations by up to 0.36 and 2.8 ppbv respectively during the growing season. At the same time, accumulated O3 exposure during the crop growing season (expressed as AOT40 values) could increase by up to 496 ppb h, leading to crop yield decline of about 0.8% for O3-sensitive crops. Our results suggest that, when accounting for the consequential impacts on surface O3 air quality and crop damage over sub-Saharan Africa, agricultural intensification is possible without substantial impacts on crop productivity because the relatively small decline of crop yield resulting from O3 damage appears unlikely to outweigh the gain in crop yield from fertilization.
Conservation tillage impacts on soil, crop and the environment

Directory of Open Access Journals (Sweden)

Mutiu Abolanle Busari

2015-06-01

Full Text Available There is an urgent need to match food production with increasing world population through identification of sustainable land management strategies. However, the struggle to achieve food security should be carried out keeping in mind the soil where the crops are grown and the environment in which the living things survive. Conservation agriculture (CA, practising agriculture in such a way so as to cause minimum damage to the environment, is being advocated at a large scale world-wide. Conservation tillage, the most important aspect of CA, is thought to take care of the soil health, plant growth and the environment. This paper aims to review the work done on conservation tillage in different agro-ecological regions so as to understand its impact from the perspectives of the soil, the crop and the environment. Research reports have identified several benefits of conservation tillage over conventional tillage (CT with respect to soil physical, chemical and biological properties as well as crop yields. Not less than 25% of the greenhouse gas effluxes to the atmosphere are attributed to agriculture. Processes of climate change mitigation and adaptation found zero tillage (ZT to be the most environmental friendly among different tillage techniques. Therefore, conservation tillage involving ZT and minimum tillage which has potential to break the surface compact zone in soil with reduced soil disturbance offers to lead to a better soil environment and crop yield with minimal impact on the environment. Keywords: Atmosphere, Greenhouse gases, Conservation tillage, Sustainable crop yield

Influence of mycorrhizal inoculation on alley cropped farms in a ...

African Journals Online (AJOL)

The use of Arbuscular mycorrhizal (AM) fungi under farmers' conditions was tried at Ajibode Village, a humid tropical environment on maize/cassava intercropped farms in an alley cropping system. Four species of AM fungi (Glomus clarum, Glomus mosseae Glomus etunicatum and Acaulospora dilatata) were used in ...
Dynamic environments of fungus-farming termite mounds exert growth-modulating effects on fungal crop parasites.

Science.gov (United States)

Katariya, Lakshya; Ramesh, Priya B; Borges, Renee M

2018-03-01

This study investigated for the first time the impact of the internal mound environment of fungus-growing termites on the growth of fungal crop parasites. Mounds of the termite Odontotermes obesus acted as (i) temperature and relative humidity (RH) 'stabilisers' showing dampened daily variation and (ii) 'extreme environments' exhibiting elevated RH and CO 2 levels, compared to the outside. Yet, internal temperatures exhibited seasonal dynamics as did daily and seasonal CO 2 levels. During in situ experiments under termite-excluded conditions within the mound, the growth of the crop parasite Pseudoxylaria was greater inside than outside the mound, i.e., Pseudoxylaria is 'termitariophilic'. Also, ex situ experiments on parasite isolates differing in growth rates and examined under controlled conditions in the absence of termites revealed a variable effect with fungal growth decreasing only under high CO 2 and low temperature conditions, reflecting the in situ parasite growth fluctuations. In essence, the parasite appears to be adapted to survive in the termite mound. Thus the mound microclimate does not inhibit the parasite but the dynamic environmental conditions of the mound affect its growth to varying extents. These results shed light on the impact of animal-engineered structures on parasite ecology, independent of any direct role of animal engineers. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.
Impacts of climate variability and change on crop yield in sub-Sahara Africa

Science.gov (United States)

Pan, S.; Zhang, J.; Yang, J.; Chen, G.; Xu, R.; Zhang, B.; Lou, Y.

2017-12-01

Much concern has been raised about the impacts of climate change and climate extremes on Africa's food security. The impact of climate change on Africa's agriculture is likely to be severe compared to other continents due to high rain-fed agricultural dependence, and limited ability to mitigate and adapt to climate change. In recent decades, warming in Africa is more pronounced and faster than the global average and this trend is likely to continue in the future. However, quantitative assessment on impacts of climate extremes and climate change on crop yield has not been well investigated yet. By using an improved agricultural module of the Dynamic Land Ecosystem Model (DLEM-AG2) driven by spatially-explicit information on land use, climate and other environmental changes, we have assessed impacts of historical climate variability and future climate change on food crop yield across the sub-Sahara Africa during1980-2016 and the rest of the 21st century (2017-2099). Our simulated results indicate that African crop yield in the past three decades shows an increasing trend primarily due to cropland expansion. However, crop yield shows substantially spatial and temporal variation due to inter-annual and inter-decadal climate variability and spatial heterogeneity of environmental drivers. Droughts have largely reduced crop yield in the most vulnerable regions of Sub-Sahara Africa. Future projections with DLEM-AG2 show that food crop production in Sub-Sahara Africa would be favored with limiting end-of-century warming to below 1.50 C.
Risk mapping of NO/sub 3/-N contamination on groundwater under intensive rice-based cropping systems in the Philippines

International Nuclear Information System (INIS)

Pascual, C.M.; Baga, M.C.S.; Valencia, D.P.

2005-01-01

The groundwater resources in a 265 ha watershed of highly diversified and intensive rice-based environment was endangered to NO/sub 3/-N contamination with spatial degree of influence and temporal vulnerability risks as affected by intensive cropping systems with application of high N-fertilizer and judicious use of groundwater for irrigation. Such nitrate contamination levels are above the World Health Organization's maximum contamination level of 10 ppm for drinking water. Tree-joining, complete cluster analysis of monthly groundwater depths on observation wells revealed three distinct groups of wells differentiated by groundwater depths. Planting of nitrate catch crops such as legumes to reduce groundwater contamination and vigorous information dissemination on ill-effects of high NO/sub 3/-N, as well as groundwater recharging were considered to reduce contamination. However, the groundwater extraction for irrigation is still sustainable due to natural recharging of rainfall and hydraulic connections from surface water along rivers and creeks. The combined-use of GIS and GPS proved useful for spatial and temporal risk mapping assessment on groundwater NO/sub 3/-N vulnerability among other geo-referenced attributes of groundwater and other environmental considerations at the study site. Such systems analysis tools can be used by planners, researchers, extension workers, students and farmers for other sustainable development and environmental risk mapping, assessment, extrapolation analysis and strategic planning of sustainable development of the environment. (author)
Humidity dependence of adhesion for silane coated microcantilevers

International Nuclear Information System (INIS)

De Boer, Maarten P.; Mayer, Thomas M.; Carpick, Robert W.; Michalske, Terry A.; Srinivasan, U.; Maboudian, R.

1999-01-01

This study examines adhesion between silane-coated micromachined surfaces that are exposed to humid conditions. Our quantitative values for interfacial adhesion energies are determined from an in-situ optical measurement of deformations in partly-adhered cantilever beams. We coated micromachined cantilevers with either ODTS (C(sub 18)H(sub 37)SiCl(sub 3)) or FDTS (C(sub 8)F(sub 17)C(sub 2)H(sub 4)SiCl(sub 3)) with the objective of creating hydrophobic surfaces whose adhesion would be independent of humidity. In both cases, the adhesion energy is significantly lower than for uncoated, hydrophilic surfaces. For relative humidities (RH) less than 95% (ODTS) and 80% (FDTS) the adhesion energy was extremely low and constant. In fact, ODTS-coated beams exposed to saturated humidity conditions and long (48 hour) exposures showed only a factor of two increase in adhesion energy. Surprisingly, FDTS coated beams, which initially have a higher contact angle (115(degree)) with water than do ODTS coated beams (112(degree)), proved to be much more sensitive to humidity. The FDTS coated surfaces showed a factor of one hundred increase in adhesion energy after a seven hour exposure to 90% RH. Atomic force microscopy revealed agglomerated coating material after exposed to high RH, suggesting a redistribution of the monolayer film. This agglomeration was more prominent for FDTS than ODTS. These findings suggest a new mechanism for uptake of moisture under high humidity conditions. At high humidities, the silane coatings can reconfigure from a surface to a bulk phase leaving behind locally hydrophilic sites which increase the average measured adhesion energy. In order for the adhesion increase to be observed, a significant fraction of the monolayer must be converted from the surface to the bulk phase
[An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

Science.gov (United States)

Wang, Hui; Li, Mei-lan; Xu, Jian-ping; Chen, Mei-xiang; Li, Wen-yong; Li, Ming

2015-10-01

The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.
Comparison of axillary and rectal temperatures for healthy Beagles in a temperature- and humidity-controlled environment.

Science.gov (United States)

Mathis, Justin C; Campbell, Vicki L

2015-07-01

To compare axillary and rectal temperature measurements obtained with a digital thermometer for Beagles in a temperature- and humidity-controlled environment. 26 healthy Beagles (17 sexually intact males and 9 sexually intact females). Dogs were maintained in a temperature- and humidity-controlled environment for 56 days before rectal and axillary temperatures were measured. Axillary and rectal temperatures were obtained in triplicate for each dog by use of a single commercially available manufacturer-calibrated digital thermometer. Mean rectal and axillary temperatures of Beagles maintained in a temperature- and humidity-controlled environment were significantly different, with a median ± SD difference of 1.4° ± 0.15°C (range, 0.7° to 2.1°C). Mean rectal and axillary temperatures were 38.7°C (range, 37.6° to 39.5°C) and 37.2°C (range, 36.6° to 38.3°C), respectively. Results of this study indicated that the historical reference of a 0.55°C gradient between rectal and axillary temperatures that has been clinically used for veterinary patients was inaccurate for healthy Beagles in a temperature- and humidity-controlled environment. Rectal and axillary temperatures can be measured in veterinary patients. Reliable interpretation of axillary temperatures may accommodate patient comfort and reduce patient anxiety when serial measurement of temperatures is necessary. Further clinical studies will be needed.
Measuring the mechanical behavior of paperboard in a changing humidity environment

Science.gov (United States)

Dennis E. Gunderson; John M. Considine

1986-01-01

âBoth the strength and stability of compressively loaded paperboard are known to be adversely affected by cyclic changes in relative humidity. Current research at the Forest Products Laboratory (FPL) seeks to observe and explain this phenomenon and to develop a simple, practical test to determine allowable "working loads" in cyclicmoisture environments. A new...
Exploring the effects of symmetrical and asymmetrical relative humidity on the performance of H{sub 2}/air PEM fuel cell at different temperatures

Energy Technology Data Exchange (ETDEWEB)

Saleh, Mahmoud M.; Okajima, Takeoshi; Kitamura, Fusao; Ohsaka, Takeo [Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Hayase, Masahiko [Development Department, NF Co., 6-3-20 Tsunashima-higashi, Kohoku-ku, Yokohama 223-8508 (Japan)

2007-02-10

This article is dedicated to study the interlinked effects of symmetric relative humidity (RH), and asymmetric RH on the performance of H{sub 2}/air PEM fuel cell at different temperatures. The symmetric and asymmetric RH were achieved by setting the cathode relative humidity (RHC) and anode relative humidity (RHA) as equal and unequal values, respectively. The cell performance was evaluated by collecting polarization curves of the cell at different RH, RHC and RHA and at different cell temperatures (T{sub cell}). The polarization curves along with the measured internal cell resistance (membrane resistance) were discussed in the light of the present fuel cell theory. The results showed that symmetric relative humidity has different impacts depending on the cell temperature. While at RH of 35% the cell can show considerable performance at T{sub cell} = 70 C, it is not so at T{sub cell} = 90 C. At T{sub cell} = 70 C, the cell potential increases with RH at lower and medium current densities but decreases with RH at higher currents. This was attributed to the different controlling processes at higher and lower current densities. This trend at 70 C is completely destroyed at 90 C. Operating our PEM fuel cell at dry H{sub 2} gas conditions (RHA = 0%) is not detrimental as operating the cell at dry Air (O{sub 2}) conditions (RHC = 0%). At RHA = 0% and humidified air, water transport by back diffusion from the cathode to the anode at the employed experimental conditions can support reasonable rehydration of the membrane and catalysts. At RHA = 0, a possible minimum RHC for considerable cell operation is temperature dependent. At RHC = 0 conditions, the cell can operate only at RHA = 100% with a loss that depends on T{sub cell}. It was found that the internal cell resistance depends on RH, RHA, RHC and T{sub cell} and it is consistent with the observed cell performance. (author)
Determining the potential productivity of food crops in controlled environments

Science.gov (United States)

Bugbee, Bruce

1992-01-01

The quest to determine the maximum potential productivity of food crops is greatly benefitted by crop growth models. Many models have been developed to analyze and predict crop growth in the field, but it is difficult to predict biological responses to stress conditions. Crop growth models for the optimal environments of a Controlled Environment Life Support System (CELSS) can be highly predictive. This paper discusses the application of a crop growth model to CELSS; the model is used to evaluate factors limiting growth. The model separately evaluates the following four physiological processes: absorption of PPF by photosynthetic tissue, carbon fixation (photosynthesis), carbon use (respiration), and carbon partitioning (harvest index). These constituent processes determine potentially achievable productivity. An analysis of each process suggests that low harvest index is the factor most limiting to yield. PPF absorption by plant canopies and respiration efficiency are also of major importance. Research concerning productivity in a CELSS should emphasize: (1) the development of gas exchange techniques to continuously monitor plant growth rates and (2) environmental techniques to reduce plant height in communities.
Vegetation Responses to Climate Variability in the Northern Arid to Sub-Humid Zones of Sub-Saharan Africa

Directory of Open Access Journals (Sweden)

Khaldoun Rishmawi

2016-11-01

Full Text Available In water limited environments precipitation is often considered the key factor influencing vegetation growth and rates of development. However; other climate variables including temperature; humidity; the frequency and intensity of precipitation events are also known to affect productivity; either directly by changing photosynthesis and transpiration rates or indirectly by influencing water availability and plant physiology. The aim here is to quantify the spatiotemporal patterns of vegetation responses to precipitation and to additional; relevant; meteorological variables. First; an empirical; statistical analysis of the relationship between precipitation and the additional meteorological variables and a proxy of vegetation productivity (the Normalized Difference Vegetation Index; NDVI is reported and; second; a process-oriented modeling approach to explore the hydrologic and biophysical mechanisms to which the significant empirical relationships might be attributed. The analysis was conducted in Sub-Saharan Africa; between 5 and 18°N; for a 25-year period 1982–2006; and used a new quasi-daily Advanced Very High Resolution Radiometer (AVHRR dataset. The results suggest that vegetation; particularly in the wetter areas; does not always respond directly and proportionately to precipitation variation; either because of the non-linearity of soil moisture recharge in response to increases in precipitation; or because variations in temperature and humidity attenuate the vegetation responses to changes in water availability. We also find that productivity; independent of changes in total precipitation; is responsive to intra-annual precipitation variation. A significant consequence is that the degree of correlation of all the meteorological variables with productivity varies geographically; so no one formulation is adequate for the entire region. Put together; these results demonstrate that vegetation responses to meteorological variation are more
Effects of grain size and humidity on fretting wear in fine-grained alumina, Al{sub 2}O{sub 3}/TiC, and zirconia

Energy Technology Data Exchange (ETDEWEB)

Krell, A. [Fraunhofer Inst. for Ceramic Technologies and Sintered Materials, Dresden (Germany); Klaffke, D. [Federal Inst. for Materials Research and Testing, Berlin (Germany)

1996-05-01

Friction and wear of sintered alumina with grain sizes between 0.4 and 3 {micro}m were measured in comparison with Al{sub 2}O{sub 3}/TiC composites and with tetragonal ZrO{sub 2} (3 mol% Y{sub 2}O{sub 3}). The dependence on the grain boundary toughness and residual microstresses is investigated, and a hierarchical order of influencing parameters is observed. In air, reduced alumina grain sizes improve the micromechanical stability of the grain boundaries and the hardness, and reduced wear is governed by microplastic deformation, with few pullout events. Humidity and water slightly reduce the friction of all of the investigated ceramics. In water, this effect reduces the wear of coarser alumina microstructures. The wear of aluminas and of the Al{sub 2}O{sub 3}/TiC composite is similar; it is lower than observed in zirconia, where extended surface cracking occurs at grain sizes as small as 0.3 {micro}m.
Transport biofuel yields from food and lignocellulosic C{sub 4} crops

Energy Technology Data Exchange (ETDEWEB)

Reijnders, L. [IBED University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam (Netherlands)

2010-01-15

In the near future, the lignocellulosic C{sub 4} crops Miscanthus and switchgrass (Panicum virgatum) are unlikely to outcompete sugarcane (Saccharum officinarum) in net energetic yearly yield of transport biofuel ha{sup -1}. This holds both for the thermochemical conversion into liquid hydrocarbons and the enzymatic conversion into ethanol. Currently, Miscanthus and switchgrass would also not seem able to outcompete corn (Zea mays) in net energetic yearly yield of liquid transport biofuel ha{sup -1}, but further development of these lignocellulosic crops may gradually lead to a different outcome. (author)
Screening boreal energy crops and crop residues for methane biofuel production

Energy Technology Data Exchange (ETDEWEB)

Lehtomaeki, A.; Rintala, J.A. [Department of Biological and Environmental Science, University of Jyvaeskylae, P.O. Box 35, FI-40014 Jyvaeskylae (Finland); Viinikainen, T.A. [Department of Chemistry, University of Jyvaeskylae, P.O. Box 35, FI-40014 Jyvaeskylae (Finland)

2008-06-15

The purpose of the study was to screen potential boreal energy crops and crop residues for their suitability in methane production and to investigate the effect of harvest time on the methane production potential of different crops. The specific methane yields of crops, determined in 100-200 d methane potential assays, varied from 0.17 to 0.49 m{sup 3} CH{sub 4} kg{sup -1} VS{sub added} (volatile solids added) and from 25 to 260 m{sup 3} CH{sub 4} t{sub ww}{sup -1} (tonnes of wet weight). Jerusalem artichoke, timothy-clover grass and reed canary grass gave the highest potential methane yields of 2900-5400 m{sup 3} CH{sub 4} ha{sup -1}, corresponding to a gross energy yield of 28-53 MWh ha{sup -1} and ca. 40,000-60,000 km ha{sup -1} in passenger car transport. The effect of harvest time on specific methane yields per VS of crops varied a lot, whereas the specific methane yields per t{sub ww} increased with most crops as the crops matured. (author)
Physiological Disorders in Closed Environment-Grown Crops for Space Life Support

Science.gov (United States)

Wheeler, Raymond; Morrow, Robert

Crop production for life support systems in space will require controlled environments where temperature, humidity, CO2, and light might differ from natural environments where plants evolved. Physiological disorders, i.e., abnormal plant growth and development, can occur under these controlled environments. Among the most common of these disorders are Ca deficiency injuries such as leaf tipburn (e.g., lettuce), blossom-end-rot in fruits (e.g., tomato and pepper), and internal tissue necrosis in fruits or tubers (e.g., cucumber and potato). Increased Ca nutrition to the plants typically has little effect on these disorders, but slowing overall growth or providing better air circulation to increase transpiration can be effective. A second common disorder is oedema or intumescence, which appears as callus-like growth or galls on leaves (e.g., sweetpotato, potato, pepper, and tomato). This disorder can be reduced by increasing the near UV radiation ( 300-400 nm) to the plants. Leaf injury and necrosis can occur under long photoperiods (e.g., tomato, potato, and pepper) and at super-elevated (i.e., ¿ than 4000 mol mol-1) CO2 concentrations (e.g., soybean, potato, and radish), and these can be managed by reducing the photoperiod and CO2 concentration, respectively. Lack of blue light in the spectrum (e.g., under red LEDs or LPS lamps) can result in leggy growth and/or leaves lacking in chlorophyll (e.g., wheat, bean, and radish). Volatile organic compounds (VOCs), most commonly ethylene, can accumulate in tightly closed systems and result in a variety of negative responses. Most of these disorders can be mitigated by altering the environmental set-points or by using more resistant cultivars.
Influence of humidity on the growth characteristics and properties of chemical bath-deposited ZnS thin films

Energy Technology Data Exchange (ETDEWEB)

Lin, Yi-Cheng; Chao, Yen-Tai [Department of Mechatronics Engineering, National Changhua University of Education, Changhua 50007, Taiwan (China); Yao, Pin-Chuan, E-mail: pcyao@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Dacun, Changhua 51591, Taiwan (China)

2014-07-01

In this study, the effect of humidity on the growth characteristics and properties of chemical bath-deposited ZnS thin films was systematically investigated. All deposition was conducted by an open CBD system under various relative humidity levels (RH) or by a hermetic CBD system as a comparison. It shows, for films deposited by an open system, the ambient humidity plays an important role in the quality of the resultant films. Damp environments lead to powdery films. Generally, all films prepared in this study using NH{sub 3} and hydrazine hydrate as the complexing agents were amorphous or poorly crystalline. For an open system, the [H{sup +}] from the dissolved carbon dioxide in the air competes with the ammonium ions in the bath solution. According to Le Châtelier's principle, more ammonia was consumed, which favors the free [Zn{sup +2}] in the solution, facilitating the homogeneous precipitation of Zn(OH){sub 2} and giving rise to a powdery film. The x-ray photoelectron spectrum shows, for an open system, the content of Zn–O compounds in the form of Zn(OH){sub 2} and ZnO, etc., is increased by the relative humidity of the environment. The visible transmittance is reduced by RH. The higher optical band gap of the as-deposited films could be attributed to the quantum confinement effects due to the small grain size of the polycrystalline ZnS films over the substrates.
Building Environment Analysis Based on Temperature and Humidity for Smart Energy Systems

Directory of Open Access Journals (Sweden)

Kwang-Ho Won

2012-10-01

Full Text Available In this paper, we propose a new HVAC (heating, ventilation, and air conditioning control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment.
Building environment analysis based on temperature and humidity for smart energy systems.

Science.gov (United States)

Yun, Jaeseok; Won, Kwang-Ho

2012-10-01

In this paper, we propose a new HVAC (heating, ventilation, and air conditioning) control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment.
Estimatation of evapotranspiration and crop coefficient of melon cultivated in protected environment

Directory of Open Access Journals (Sweden)

Cláudia S. Lozano

Full Text Available ABSTRACT The objective of this work was to determine the water consumption and the crop coefficient of melon in a protected environment. The experiment was conducted in a greenhouse at the Technical Center of Irrigation of the State University of Maringá, in Maringá, PR. The melon hybrid used was Sunrise and the irrigations were performed daily by drip irrigation. Crop water requirement was quantified based on its evapotranspiration directly measured through constant water table lysimeters. Weather information was collected in an automatic weather station, installed inside the protected environment, which allowed to calculate the reference evapotranspiration by the Penman-Monteith method. The total water consumption of the melon crop was 295 mm, reaching maximum crop evapotranspiration of 5.16 mm d-1. The phenological stages were shorter in the initial, growth and intermediate phases, compared with the data from FAO. The determined crop coefficients were 0.87, 1.15 and 0.64 for the initial, intermediate and final stages, respectively
Mouth rinsing improves cycling endurance performance during Ramadan fasting in a hot humid environment.

Science.gov (United States)

Che Muhamed, Ahmad Munir; Mohamed, Nazirah Gulam; Ismail, Norjana; Aziz, Abdul Rashid; Singh, Rabindarjeet

2014-04-01

This study examined the effect of mouth rinsing during endurance cycling in a hot humid environment (32 °C and 75% relative humidity) on athletes in the Ramadan fasted state. Nine trained adolescent male cyclists completed 3 trials that consisted of a carbohydrate mouth-rinse (CMR), a placebo mouth-rinse (PMR), and a no-rinse (NOR) trial during the last 2 weeks of Ramadan. Each trial consisted of a preloading cycle at 65% peak rate of oxygen consumption for 30 min followed by a 10-km time trial (TT10 km) under hot humid condition. During the CMR and PMR trials, each cyclist rinsed his mouth with 25 mL of the solution for 5 s before expectorating the solution pre-exercise, after 5, 15, and 25 min of the preloading cycle, and 15 s prior to the start of TT10 km. Time to complete the TT10 km was significantly faster in the CMR and PMR trials compared with the NOR trial (12.9 ± 1.7 and 12.6 ± 1.7 vs. 16.8 ± 1.6 min, respectively; p benefits compared with a no-rinse condition on TT10 km performance in acute Ramadan fasted subjects during endurance cycling in a heat stress environment.

Proposition of Regression Equations to Determine Outdoor Thermal Comfort in Tropical and Humid Environment

Directory of Open Access Journals (Sweden)

Sangkertadi Sangkertadi

2012-05-01

Full Text Available This study is about field experimentation in order to construct regression equations of perception of thermalcomfort for outdoor activities under hot and humid environment. Relationships between thermal-comfort perceptions, micro climate variables (temperatures and humidity and body parameters (activity, clothing, body measure have been observed and analyzed. 180 adults, men, and women participated as samples/respondents. This study is limited for situation where wind velocity is about 1 m/s, which touch the body of the respondents/samples. From questionnaires and field measurements, three regression equations have been developed, each for activity of normal walking, brisk walking, and sitting.
The role of groundwater in streamflow in a headwater catchment with sub-humid climate

Science.gov (United States)

Liu, Yaping; Tian, Fuqiang; Hu, Hongchang; Tie, Qiang

2015-04-01

Recent studies have suggested that bedrock groundwater can exert considerable influence on streamflow in headwater catchments under humid climate. However, study of the role of bedrock groundwater is still challenged due to limited direct observation data. In this study, by utilizing observed hydrometric and hydrochemical data, we aimed at characterize the bedrock groundwater's response to rainfall at hillslope and catchment scales in a small headwater catchment with sub-humid climate. We selected Xitaizi catchment with area of 6.7 km in the earth-rock mountain region, which located in the north of Beijing, China, as study area. The catchment bedrock is mainly consist of fractured granite. Four weather stations were installed to observe the weather condition and soil volumetric water content (VWC) at depth of 10-60 cm with 10-minute interval. Five wells with depth of 10 m were drilled in two slopes to monitor the bedrock water table by pneumatic water gauge. At slope 1, the soil VWC at depth of 10-80 cm were also observed by soil moisture sensors, and surface/subsurface hillslope runoff at three different layers (0-20cm, 20-80cm, 80-300cm) was observed by three recording buckets. Field works were conducted from July 2013 to November 2014. During the period, precipitation, river, spring and groundwater were sampled nearly monthly. Water temperature, electrical conductivity (EC) and pH were measured in site with portable instruments. In addition, the precipitation, river and groundwater were also sampled intensively during two storm events. All the samples were subjected to stable isotope analysis, the samples taken monthly during the period from July 2013 to July 2014 were subjected to hydrochemistry analysis. Our results show that: (1) the bedrock groundwater is the dominant component of streamflow in the headwater catchment with sub-humid climate; (2) stream is recharged by groundwater sourcing from different mountains with different hydrochemistry characteristics
The anthropogenic influence on heat and humidity in the US Midwest

Science.gov (United States)

Inda Diaz, H. A.; O'Brien, T. A.; Stone, D. A.

2016-12-01

Heatwaves, and extreme temperatures in general, have a wide range of negative impacts on society, and particularly on human health. In addition to temperature, humidity plays a key role in regulating human body temperature, with higher humidities tending to reduce the effectiveness of perspiration. There is recent theoretical and observational evidence that co-occurring extreme heat and humidity can potentially have a much more dramatic impact on human health than either extreme in isolation. There is an abundance of observational evidence indicating that anthropogenic increases in greenhouse gas (GHG) forcing have contributed to an increase in the intensity and frequency of temperature extremes on a global scale. However, aside from purely thermodynamically-driven increases in near-surface humidity, there is a paucity of similar evidence for anthropogenic impacts on humidity. Thermodynamic scaling would suggest that air masses originating from the ocean would be associated with higher specific humidity in a warmer world, and transpiration from irrigated crops could further increase humidity in warm air masses. In order to explore the role of anthropogenic GHG forcing on the co-occurrence of temperature and humidity extremes in the Midwestern United States (US), we evaluate a large ensemble of global climate model simulations with and without anthropogenic GHG forcing. In particular, we examine differences between the probability distributions of near-surface temperature, humidity, wet-bulb temperature, and the joint distribution of temperature and humidity in this ensemble. Finally, we explore augmenting this experimental framework with additional simulations to explore the role of anthropogenic changes in the land surface, and in particular irrigated crops, on co-occurring extreme heat and humidity.
JULES-crop: a parametrisation of crops in the Joint UK Land Environment Simulator

Science.gov (United States)

Osborne, T.; Gornall, J.; Hooker, J.; Williams, K.; Wiltshire, A.; Betts, R.; Wheeler, T.

2014-10-01

Studies of climate change impacts on the terrestrial biosphere have been completed without recognition of the integrated nature of the biosphere. Improved assessment of the impacts of climate change on food and water security requires the development and use of models not only representing each component but also their interactions. To meet this requirement the Joint UK Land Environment Simulator (JULES) land surface model has been modified to include a generic parametrisation of annual crops. The new model, JULES-crop, is described and evaluation at global and site levels for the four globally important crops; wheat, soy bean, maize and rice is presented. JULES-crop demonstrates skill in simulating the inter-annual variations of yield for maize and soy bean at the global level, and for wheat for major spring wheat producing countries. The impact of the new parametrisation, compared to the standard configuration, on the simulation of surface heat fluxes is largely an alteration of the partitioning between latent and sensible heat fluxes during the later part of the growing season. Further evaluation at the site level shows the model captures the seasonality of leaf area index and canopy height better than in standard JULES. However, this does not lead to an improvement in the simulation of sensible and latent heat fluxes. The performance of JULES-crop from both an earth system and crop yield model perspective is encouraging however, more effort is needed to develop the parameterisation of the model for specific applications. Key future model developments identified include the specification of the yield gap to enable better representation of the spatial variability in yield.
Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

Energy Technology Data Exchange (ETDEWEB)

Larsen, Søren Thor, E-mail: stl@nrcwe.dk; Wolkoff, Peder, E-mail: pwo@nrcwe.dk; Hammer, Maria, E-mail: mha@nrcwe.dk; Kofoed-Sørensen, Vivi, E-mail: vks@nrcwe.dk; Clausen, Per Axel, E-mail: pac@nrcwe.dk; Nielsen, Gunnar Damgård, E-mail: gdn@nrcwe.dk

2013-05-01

We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation.
Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

International Nuclear Information System (INIS)

Larsen, Søren Thor; Wolkoff, Peder; Hammer, Maria; Kofoed-Sørensen, Vivi; Clausen, Per Axel; Nielsen, Gunnar Damgård

2013-01-01

We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation
Exclusion of soil macrofauna did not affect soil quality but increases crop yields in a sub-humid tropical maize-based system

NARCIS (Netherlands)

Paul, B.K.; Vanlauwe, B.; Hoogmoed, M.; Hurisso, T.T.; Ndabamenye, T.; Terano, Y.; Ayuke, F.O.; Pulleman, M.M.

2015-01-01

Soil macrofauna such as earthworms and termites are involved in key ecosystem functions and thus considered important for sustainable intensification of crop production. However, their contribution to tropical soil and crop performance, as well as relations with agricultural management (e.g.
A critical assessment of the JULES land surface model hydrology for humid tropical environments

Science.gov (United States)

Zulkafli, Z.; Buytaert, W.; Onof, C.; Lavado, W.; Guyot, J. L.

2013-03-01

Global land surface models (LSMs) such as the Joint UK Land Environment Simulator (JULES) are originally developed to provide surface boundary conditions for climate models. They are increasingly used for hydrological simulation, for instance to simulate the impacts of land use changes and other perturbations on the water cycle. This study investigates how well such models represent the major hydrological fluxes at the relevant spatial and temporal scales - an important question for reliable model applications in poorly understood, data-scarce environments. The JULES-LSM is implemented in a 360 000 km2 humid tropical mountain basin of the Peruvian Andes-Amazon at 12-km grid resolution, forced with daily satellite and climate reanalysis data. The simulations are evaluated using conventional discharge-based evaluation methods, and by further comparing the magnitude and internal variability of the basin surface fluxes such as evapotranspiration, throughfall, and surface and subsurface runoff of the model with those observed in similar environments elsewhere. We find reasonably positive model efficiencies and high correlations between the simulated and observed streamflows, but high root-mean-square errors affecting the performance in smaller, upper sub-basins. We attribute this to errors in the water balance and JULES-LSM's inability to model baseflow. We also found a tendency to under-represent the high evapotranspiration rates of the region. We conclude that strategies to improve the representation of tropical systems to be (1) addressing errors in the forcing and (2) incorporating local wetland and regional floodplain in the subsurface representation.
The Potential Role of Neglected and Underutilised Crop Species as Future Crops under Water Scarce Conditions in Sub-Saharan Africa

Science.gov (United States)

Chivenge, Pauline; Mabhaudhi, Tafadzwanashe; Modi, Albert T.; Mafongoya, Paramu

2015-01-01

Modern agricultural systems that promote cultivation of a very limited number of crop species have relegated indigenous crops to the status of neglected and underutilised crop species (NUCS). The complex interactions of water scarcity associated with climate change and variability in sub-Saharan Africa (SSA), and population pressure require innovative strategies to address food insecurity and undernourishment. Current research efforts have identified NUCS as having potential to reduce food and nutrition insecurity, particularly for resource poor households in SSA. This is because of their adaptability to low input agricultural systems and nutritional composition. However, what is required to promote NUCS is scientific research including agronomy, breeding, post-harvest handling and value addition, and linking farmers to markets. Among the essential knowledge base is reliable information about water utilisation by NUCS with potential for commercialisation. This commentary identifies and characterises NUCS with agronomic potential in SSA, especially in the semi-arid areas taking into consideration inter alia: (i) what can grow under water-scarce conditions, (ii) water requirements, and (iii) water productivity. Several representative leafy vegetables, tuber crops, cereal crops and grain legumes were identified as fitting the NUCS category. Agro-biodiversity remains essential for sustainable agriculture. PMID:26016431
The Potential Role of Neglected and Underutilised Crop Species as Future Crops under Water Scarce Conditions in Sub-Saharan Africa

Directory of Open Access Journals (Sweden)

Pauline Chivenge

2015-05-01

Full Text Available Modern agricultural systems that promote cultivation of a very limited number of crop species have relegated indigenous crops to the status of neglected and underutilised crop species (NUCS. The complex interactions of water scarcity associated with climate change and variability in sub-Saharan Africa (SSA, and population pressure require innovative strategies to address food insecurity and undernourishment. Current research efforts have identified NUCS as having potential to reduce food and nutrition insecurity, particularly for resource poor households in SSA. This is because of their adaptability to low input agricultural systems and nutritional composition. However, what is required to promote NUCS is scientific research including agronomy, breeding, post-harvest handling and value addition, and linking farmers to markets. Among the essential knowledge base is reliable information about water utilisation by NUCS with potential for commercialisation. This commentary identifies and characterises NUCS with agronomic potential in SSA, especially in the semi-arid areas taking into consideration inter alia: (i what can grow under water-scarce conditions, (ii water requirements, and (iii water productivity. Several representative leafy vegetables, tuber crops, cereal crops and grain legumes were identified as fitting the NUCS category. Agro-biodiversity remains essential for sustainable agriculture.
Biogas production from energy crops and crop residues

Energy Technology Data Exchange (ETDEWEB)

Lehtomaeki, A.

2006-07-01

The feasibility of utilising energy crops and crop residues in methane production through anaerobic digestion in boreal conditions was evaluated in this thesis. Potential boreal energy crops and crop residues were screened for their suitability for methane production, and the effects of harvest time and storage on the methane potential of crops was evaluated. Codigestion of energy crops and crop residues with cow manure, as well as digestion of energy crops alone in batch leach bed reactors with and without a second stage upflow anaerobic sludge blanket reactor (UASB) or methanogenic filter (MF) were evaluated. The methane potentials of crops, as determined in laboratory methane potential assays, varied from 0.17 to 0.49 m3 CH{sub 4} kg-1 VS{sub added} (volatile solids added) and from 25 to 260 m3 CH4 t-1 ww (tons of wet weight). Jerusalem artichoke, timothy-clover and reed canary grass gave the highest methane potentials of 2 900-5 400 m3 CH{sub 4} ha-1, corresponding to a gross energy potential of 28-53 MWh ha-1 and 40 000-60 000 km ha-1 in passenger car transport. The methane potentials per ww increased with most crops as the crops matured. Ensiling without additives resulted in minor losses (0-13%) in the methane potential of sugar beet tops but more substantial losses (17-39%) in the methane potential of grass, while ensiling with additives was shown to have potential in improving the methane potentials of these substrates by up to 19-22%. In semi-continuously fed laboratory continuously stirred tank reactors (CSTRs) co-digestion of manure and crops was shown feasible with feedstock VS containing up to 40% of crops. The highest specific methane yields of 0.268, 0.229 and 0.213 m3 CH{sub 4} kg-1 VS{sub added} in co-digestion of cow manure with grass, sugar beet tops and straw, respectively, were obtained with 30% of crop in the feedstock, corresponding to 85-105% of the methane potential in the substrates as determined by batch assays. Including 30% of crop in
Odors and sensations of humidity and dryness in relation to sick building syndrome and home environment in Chongqing, China.

Directory of Open Access Journals (Sweden)

Juan Wang

Full Text Available The prevalence of perceptions of odors and sensations of air humidity and sick building syndrome symptoms in domestic environments were studied using responses to a questionnaire on the home environment. Parents of 4530 1-8 year old children from randomly selected kindergartens in Chongqing, China participated. Stuffy odor, unpleasant odor, pungent odor, mold odor, tobacco smoke odor, humid air and dry air in the last three month (weekly or sometimes was reported by 31.4%, 26.5%, 16.1%, 10.6%, 33.0%, 32.1% and 37.2% of the parents, respectively. The prevalence of parents' SBS symptoms (weekly or sometimes were: 78.7% for general symptoms, 74.3% for mucosal symptoms and 47.5% for skin symptoms. Multi-nominal regression analyses for associations between odors/sensations of air humidity and SBS symptoms showed that the odds ratio for "weekly" SBS symptoms were consistently higher than for "sometimes" SBS symptoms. Living near a main road or highway, redecoration, and new furniture were risk factors for perceptions of odors and sensations of humid air and dry air. Dampness related problems (mold spots, damp stains, water damage and condensation were all risk factors for perceptions of odors and sensations of humid air and dry air, as was the presence of cockroaches, rats, and mosquitoes/flies, use of mosquito-repellent incense and incense. Protective factors included cleaning the child's bedroom every day and frequently exposing bedding to sunshine. In conclusion, adults' perceptions of odors and sensations of humid air and dry air are related to factors of the home environment and SBS symptoms are related to odor perceptions.
Variations of relative humidity in relation to meningitis in Africa

Science.gov (United States)

Seefeldt, M. W.; Hopson, T. M.

2011-12-01

The meningitis belt is a region covering Sub-Saharan Africa from the Sahel of West Africa eastward to western Ethiopia. The region is prone to meningitis epidemics during the dry season extending from approximately January to May, depending on the region. Relative humidity has been found to be a critical environmental factor indicating the susceptibility of a region to meningitis epidemics. This study evaluates the variation of relative humidity across West Africa over 30 dry-seasons (1979 - 2009) using the NASA-MERRA dataset. The method of self-organizing maps is employed to characterize the changes in relative humidity patterns across the region within a given dry season as well as changes over the 30 years. A general pattern of changes in relative humidity is indicated as the rainbelt retreats to the south at the onset of the dry season and then returns to the region at the end of the dry season. Within each dry season there is a unique pattern. The climatological conditions of relative humidity at the onset of the dry season provide an indication of the moisture environment for the entire dry season. Year to year variation in the relative humidity patterns are found to be gradual. Future applications involve using the results from the SOM evaluation to be used for future decisions involving prevention of meningitis epidemics.
Climate change impacts on crop yields, land use and environment in response to crop sowing dates and thermal time requirements

NARCIS (Netherlands)

Zimmermann, Andrea; Webber, Heidi; Zhao, Gang; Ewert, Frank; Kros, Hans; Wolf, Joost; Britz, Wolfgang; Vries, de Wim

2017-01-01

Impacts of climate change on European agricultural production, land use and the environment depend on its impact on crop yields. However, many impact studies assume that crop management remains unchanged in future scenarios, while farmers may adapt their sowing dates and cultivar thermal time
Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

Directory of Open Access Journals (Sweden)

Rong Chen

2013-01-01

Full Text Available A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1 measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2 implementing questionnaire survey analysis to explore people’s environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3 constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV, two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1~0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement.
Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

Science.gov (United States)

Chen, Rong; Sung, Wen-Pei; Chang, Hung-Chang; Chi, Yi-Rou

2013-01-01

A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1) measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2) implementing questionnaire survey analysis to explore people's environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3) constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV), two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C) indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1 ~ 0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement. PMID:24311976
Environment Humidity Effect on the Weight of Carbonized Na-Al-Si Glass Fabrics Recovery after Heating

International Nuclear Information System (INIS)

Pentjuss, E; Lusis, A; Gabrusenoks, J; Bajars, G

2015-01-01

Na-Al-Si glass fabrics fibres contain Na + ions that diffuse to its surface and along with CO 2 and H 2 O from atmosphere create here the shell of carbonate hydrates. The heating of fabric leads to weight loss by evolving these substances. In this work the results of weight recovery study at room relative humidity (20% – 50%) and elevated humidity (near 70%) of fabrics after its heating at different temperatures (70°C – 150°C) are compared. The experiments shoved the different weight recovery kinetics. The initial exponential stages up to 0.3 h – 0.5 h of the both recoveries are associated with water absorption and differ by its levels. In a case of lower environment humidity the later weight increase are restricted by its value, but at an elevated humidity has a maximum and followed weight increase. The reasons of observed differences are discussed
Short Oligonucleotides Aligned in Stretched Humid Matrix: Secondary DNA Structure in Poly(vinyl alcohol) Environment

KAUST Repository

Hanczyc, Piotr; Å kerman, Bjö rn; Nordé n, Bengt

2012-01-01

) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.4 nm) were investigated with respect to structural properties in the gel-like polymer environment. The DNA conformation as a function of relative humidity reveals a strong
Searching for new solutions Humidity measurements in the environments

Directory of Open Access Journals (Sweden)

Gianina Creţu

2008-05-01

Full Text Available More attention is nowadays being paid to thequality of the air we breathe, resulting in an increasingneed for humidity measurements in the home and officeenvironments. Maintaining the proper level of relativehumidity is also necessary to avoid conditions of extremehumidity condensation in buildings.The facts that construction problems and excessive waterand humidity often go together is well-known around theworld today. Moisture and water damage is a wellknown problem in construction in many countries.Problems of all construction are caused by humidity and50 per cent of all buildings have some kind of moisturerelatedproblems. Growing awareness of percentages suchas these has led to greater attention being paid toconstruction humidity and its measurement throughoutthe world in recent years.This paper presents a condensed review of nowadayshumidity sensors technology, problem implicated andsome modern tendencies.
The formation of fire residues associated with hunter-gatherers in humid tropical environments: A geo-ethnoarchaeological perspective

Science.gov (United States)

Friesem, David E.; Lavi, Noa; Madella, Marco; Boaretto, Elisabetta; Ajithparsad, P.; French, Charles

2017-09-01

Tropical forests have been an important human habitat and played a significant role in early human dispersal and evolution. Likewise, the use of fire, besides being one of the exceptional characteristics of humans, serves as a marker for human evolution. While the use of fire by prehistoric hunter-gatherers is relatively well documented in arid and temperate environments, the archaeological evidence in humid tropical environment is to date very limited. We first review the archaeological evidence for hunter-gatherer use of fire in humid tropical environments and suggest that better understanding of formation processes is required. We present a geo-ethnoarchaeological study from South India, involving ethnography, excavations and laboratory-based analyses in order to build a new framework to study fire residues in humid tropical forests associated with hunter-gatherer's use of fire. Ethnographic observations point to a dynamic and ephemeral use of hearths. Hearths location were dictated by the social and ever-changing social dynamics of the site. The hearths deposited small amount of residues which were later swept on a daily basis, re-depositing ash and charcoal in waste areas and leaving only a microscopic signal in the original location. Particular acidic conditions and intensive biological activity within tropical sediments result in the complete dissolution of ash and bones while favouring the preservation of charcoal and phytoliths. Consequently, the identification of fire residues in humid tropical forests and the reconstruction of the human use of fire must involve multi-proxy microscopic analysis to detect its micro-signatures.

Recommended values of the humidity correction factor k{sub n} for determining exposure in an X-ray beam with free-air chambers; Valores recomendados del factor de correccion por humedad, k{sub h} para la determinacion de la exposicion en un haz de rayos X usando camaras de paredes de aire

Energy Technology Data Exchange (ETDEWEB)

Los Arcos, J M; Brosed, A

1983-07-01

The experimental values stated by CCEMRI (Section I) concerning the humidity correction factor k{sub h} required for determining exposure in an X-ray beam with free-air chambers are commented and a method to estimate k{sub n} numerically, at any particular combination of relative humidity, pressure and temperature, la explained. A table of k{sub h}, calculated for relative humidity varying from 0% to 90%, for pressures in the range of 70 kPa to 104kPa and temperatures between 15 degree centigree and 30 degree centigree, is included. (Author) 10 refs.
Standard Test Methods for Photovoltaic Modules in Cyclic Temperature and Humidity Environments

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 These test methods provide procedures for stressing photovoltaic modules in simulated temperature and humidity environments. Environmental testing is used to simulate aging of module materials on an accelerated basis. 1.2 Three individual environmental test procedures are defined by these test methods: a thermal cycling procedure, a humidity-freeze cycling procedure, and an extended duration damp heat procedure. Electrical biasing is utilized during the thermal cycling procedure to simulate stresses that are known to occur in field-deployed modules. 1.3 These test methods define mounting methods for modules undergoing environmental testing, and specify parameters that must be recorded and reported. 1.4 These test methods do not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of these test methods. 1.5 Any of the individual environmental tests may be performed singly, or may be combined into a test sequence with other environmental or non-envir...
Effects of Humidity and Surfaces on the Melt Crystallization of Ibuprofen

OpenAIRE

Lee, Dong-Joo; Lee, Suyang; Kim, Il Won

2012-01-01

Melt crystallization of ibuprofen was studied to understand the effects of humidity and surfaces. The molecular self-assembly during the amorphous-to-crystal transformation was examined in terms of the nucleation and growth of the crystals. The crystallization was on Al, Au, and self-assembled monolayers with –CH3sub>, –OH, and –COOH functional groups. Effects of the humidity were studied at room temperature (18–20 °C) with relative humidity 33%, 75%, and 100%. Effects of t...
Humidity fluctuations in the marine boundary layer measured at a coastal site with an infrared humidity sensor

DEFF Research Database (Denmark)

Sempreviva, A.M.; Gryning, Sven-Erik

1996-01-01

An extensive set of humidity turbulence data has been analyzed from 22-m height in the marine boundary layer. Fluctuations of humidity were measured by an ''OPHIR'', an infrared humidity sensor with a 10 Hz scanning frequency and humidity spectra were produced. The shapes of the normalized spectra...... follow the established similarity functions. However the 10-min time averaged measurements underestimate the value of the absolute humidity. The importance of the humidity flux contribution in a marine environment in calculating the Obukhov stability length has been studied. Deviations from Monin......-Obukhov similarity theory seem to be connected to a low correlation between humidity and temperature....
Effect of irrigation techniques and strategies on water footprint of growing crops

Science.gov (United States)

Chukalla, A. D.; Krol, M. S.; Hoekstra, A. Y. Y.

2014-12-01

Reducing the water footprint (WF) of growing crops, the largest water user and a significant contributor to the WF of many consumer products, plays a significant role in integrated and sustainable water management. The water footprint for growing crop is accounted by relating the crop yield with the corresponding consumptive water use (CWU), which both can be adjusted by measures that affect the crop growth and root-zone soil water balance. This study explored the scope for reducing the water footprint of irrigated crops by experimenting set of field level technical and managerial measures: (i) irrigation technologies (Furrow, sprinkler, drip and sub-surface drip), (ii) irrigation strategies (full and a range of sustained and controlled deficit) and (iii) field management options (zero, organic and synthetic mulching). Ranges of cases were also considered: (a) Arid and semi-arid environment (b) Loam and Sandy-loam soil types and (c) for Potato, Wheat and Maize crops; under (c) wet, normal and dry years. AquaCrop, the water driven crop growth and soil water balance model, offered the opportunity to systematically experiment these measures on water consumption and yield. Further, the green and blue water footprints of growing crop corresponding to each measure were computed by separating the root zone fluxes of the AquaCrop output into the green and blue soil water stocks and their corresponding fluxes. Results showed that in arid environment reduction in irrigation supply, CWU and WF up to 300 mm, 80 mm and 75 m3/tonne respectively can be achieved for Maize by a combination of organic mulching and drip technology with controlled deficit irrigation strategies (10-20-30-40% deficit with reference to the full irrigation requirement). These reductions come with a yield drop of 0.54 tonne/ha. In the same environment under the absence of mulching practice, the sub-surface drip perform better in reducing CWU and WF of irrigated crops followed by drip and furrow irrigation
Air humidity requirements for human comfort

DEFF Research Database (Denmark)

Toftum, Jørn; Fanger, Povl Ole

1999-01-01

level near 100% rh. For respiratory comfort are the requirements much more stringent and results in lower permissible indoor air humidities. Compared with the upper humidity limit specified in existing thermal comfort standards, e.g. ASHRAE Addendum 55a, the humidity limit based on skin humidity......Upper humidity limits for the comfort zone determined from two recently presented models for predicting discomfort due to skin humidity and insufficient respiratory cooling are proposed. The proposed limits are compared with the maximum permissible humidity level prescribed in existing standards...... for the thermal indoor environment. The skin humidity model predicts discomfort as a function of the relative humidity of the skin, which is determined by existing models for human heat and moisture transfer based on environmental parameters, clothing characteristics and activity level. The respiratory model...
Effects of Climate Change on the Yield and Cropping Area of Major Food Crops: A Case of Bangladesh

Directory of Open Access Journals (Sweden)

Md. Ruhul Amin

2015-01-01

Full Text Available The crops that we grow for food need specific climatic conditions to show better performance in view of economic yield. A changing climate could have both beneficial and harmful effects on crops. Keeping the above view in mind, this study is undertaken to investigate the impacts of climate change (viz. changes in maximum temperature, minimum temperature, rainfall, humidity and sunshine on the yield and cropping area of four major food crops (viz. Aus rice, Aman rice, Boro rice and wheat in Bangladesh. Heteroskedasticity and autocorrelation consistent standard error (HAC and feasible generalized least square (FGLS methods were used to determine the climate-crop interrelations using national level time series data for the period of 1972–2010. Findings revealed that the effects of all the climate variables have had significant contributions to the yield and cropping area of major food crops with distinct variation among them. Maximum temperature statistically significantly affected all the food crops’ yield except Aus rice. Maximum temperature also insignificantly affected cropping area of all the crops. Minimum temperature insignificantly affected Aman rice but benefited other three crops’ yield and cropping area. Rainfall significantly benefitted cropping area of Aus rice, but significantly affected both yield and cropping area of Aman rice. Humidity statistically positively contributed to the yield of Aus and Aman rice but, statistically, negatively influenced the cropping area of Aus rice. Sunshine statistically significantly benefitted only Boro rice yield. Overall, maximum temperature adversely affected yield and cropping area of all the major food crops and rainfall severely affected Aman rice only. Concerning the issue of climate change and ensuring food security, the respective authorities thus should give considerable attention to the generation, development and extension of drought (all major food crops and flood (particularly Aman
Process-based humidity control regime for greenhouse crops

NARCIS (Netherlands)

Korner, O.; Challa, H.

2003-01-01

Modern greenhouses in The Netherlands are designed for efficient use of energy. Climate control traditionally aims at optimal crop performance. However, energy saving is a major issue for the development of new temperature regimes. Temperature integration (TI) results in fluctuating and often high
Effects of SO/sub 2/ in atmosphere upon field crops in the Ostrava region

Energy Technology Data Exchange (ETDEWEB)

Nekovar, J

1974-01-01

The Ostrava branch of the Research Institute for Hydrometeorology studied three years in succession (1969, 1970 and 1971) effects of SO/sub 2/ present in the atmosphere in the Ostrava region upon the field crops. Eleven plots - all close to air pollution measuring stations - were chosen for biometric measurements and observation of plant growth. The stations sample daily air and measure the concentrations of sulfur dioxide and dust. Plants under observation were grown in special boxes. The seed, sowing time, germination conditions, composition of soil, etc.,. were strictly the same for all plots. The article deals with the results of the study, i.e. with the harmful effects of pollutants present in the air upon various field crops, i.e. barley, oats and beans. From biometric data, diagrams of growth during the vegetation period, measurements of SO/sub 3/ and fly ash concentrations, as well as yields given by plants, the author classifies the conditions in various localities. 11 references, 4 figures, 2 tables.
Deforestation risk due to commodity crop expansion in sub-Saharan Africa

Science.gov (United States)

Ordway, Elsa M.; Asner, Gregory P.; Lambin, Eric F.

2017-04-01

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crops to sub-Saharan Africa (SSA). We assess the effects of domestic- and export-oriented agricultural expansion on deforestation in SSA in recent decades. Analyses were conducted at the global, regional and local scales. We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Côte d’Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ± 17.93) and lowest proportions of potentially available cropland outside forest areas (1% ± 0.89). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41 582 thousand ha. Cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1. However, cocoa only amounted to 0.89% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Land-use changes associated with large-scale investments remain to be observed in many countries. Although domestic demand for commodity crops was associated with most agricultural expansion, we provide evidence of a growing influence of distant markets on land-use change in SSA.
Storage of Maize in Purdue Improved Crop Storage (PICS) Bags.

Science.gov (United States)

Williams, Scott B; Murdock, Larry L; Baributsa, Dieudonne

2017-01-01

Interest in using hermetic technologies as a pest management solution for stored grain has risen in recent years. One hermetic approach, Purdue Improved Crop Storage (PICS) bags, has proven successful in controlling the postharvest pests of cowpea. This success encouraged farmers to use of PICS bags for storing other crops including maize. To assess whether maize can be safely stored in PICS bags without loss of quality, we carried out laboratory studies of maize grain infested with Sitophilus zeamais (Motshulsky) and stored in PICS triple bags or in woven polypropylene bags. Over an eight month observation period, temperatures in the bags correlated with ambient temperature for all treatments. Relative humidity inside PICS bags remained constant over this period despite the large changes that occurred in the surrounding environment. Relative humidity in the woven bags followed ambient humidity closely. PICS bags containing S. zeamais-infested grain saw a significant decline in oxygen compared to the other treatments. Grain moisture content declined in woven bags, but remained high in PICS bags. Seed germination was not significantly affected over the first six months in all treatments, but declined after eight months of storage when infested grain was held in woven bags. Relative damage was low across treatments and not significantly different between treatments. Overall, maize showed no signs of deterioration in PICS bags versus the woven bags and PICS bags were superior to woven bags in terms of specific metrics of grain quality.
Development of relative humidity models by using optimized neural network structures

Energy Technology Data Exchange (ETDEWEB)

Martinez-romero, A.; Ortega, J. F.; Juan, J. A.; Tarjuelo, J. M.; Moreno, M. A.

2010-07-01

Climate has always had a very important role in life on earth, as well as human activity and health. The influence of relative humidity (RH) in controlled environments (e.g. industrial processes in agro-food processing, cold storage of foods such as fruits, vegetables and meat, or controls in greenhouses) is very important. Relative humidity is a main factor in agricultural production and crop yield (due to the influence on crop water demand or the development and distribution of pests and diseases, for example). The main objective of this paper is to estimate RH [maximum (RHmax), average (RHave), and minimum (RHmin)] data in a specific area, being applied to the Region of Castilla-La Mancha (C-LM) in this case, from available data at thermo-pluviometric weather stations. In this paper Artificial neural networks (ANN) are used to generate RH considering maximum and minimum temperatures and extraterrestrial solar radiation data. Model validation and generation is based on data from the years 2000 to 2008 from 44 complete agroclimatic weather stations. Relative errors are estimated as 1) spatial errors of 11.30%, 6.80% and 10.27% and 2) temporal errors of 10.34%, 6.59% and 9.77% for RHmin, RHmax and RHave, respectively. The use of ANNs is interesting in generating climate parameters from available climate data. For determining optimal ANN structure in estimating RH values, model calibration and validation is necessary, considering spatial and temporal variability. (Author) 44 refs.
Functional regulation of Pb-Ti/MoS{sub 2} composite coatings for environmentally adaptive solid lubrication

Energy Technology Data Exchange (ETDEWEB)

Ren, Siming [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Li, Hao [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Cui, Mingjun [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Wang, Liping, E-mail: wangliping@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Pu, Jibin, E-mail: pujibin@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Key Laboratory of Marine Materials and Protective Technologies of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

2017-04-15

Highlights: • Co-doped Pb-Ti/MoS{sub 2} composite coatings were successfully fabricated by unbalanced magnetron sputtering system. • Co-doped Pb-Ti/MoS{sub 2} composite coatings showed lower friction coefficient and longer wear life in both humid and vacuum environments than that of single-doped ones. • The wear behaviours of Pb-Ti/MoS{sub 2} composite coatings with the increase of Pb content is in accordance with the variation in H/E ratio that higher H/E is corresponding to the lower wear rate of coating. - Abstract: The lubrication of molybdenum disulfide coatings has commonly been limited by the application environments, for instance, the crystal MoS{sub 2} are easily affected by water to form MoO{sub 3} that causes a higher friction coefficient and short lifetime. Therefore, to improve the tribolgical performance of MoS{sub 2} in high humidity condition, the co-doped Pb-Ti/MoS{sub 2} composite coatings are deposited by unbalanced magnetron sputtering system. The design of the co-doping elements in MoS{sub 2}-based coatings can not only maintain the characteristic of low humidity-sensitivity as the Ti/MoS{sub 2} coating but also improve the mechanical properties and tribological performance of coatings as a comparison with single-doped ones. Moreover, the ultra-low friction coefficient with a minimum value of 0.006 under the vacuum condition is achieved for Pb-Ti/MoS{sub 2} composite coating containing about 4.6 at.% Pb, depending on the densification structure of coating. Intriguingly, the wear behaviours of Pb-Ti/MoS{sub 2} composite coatings are in accordance with the variation in H/E (hardness to the elastic modulus) ratio that the coating with higher H/E exhibits lower wear rate. These results demonstrate that the lubricating properties of MoS{sub 2} coatings in both humid environment and vacuum condition can be achieved through the Pb and Ti co-doped, which is of great significant for developing MoS{sub 2} coatings as the environmentally adaptive
Study on the Correlation between Humidity and Material Strains in Separable Micro Humidity Sensor Design

Directory of Open Access Journals (Sweden)

Chih-Yuan Chang

2017-05-01

Full Text Available Incidents of injuries caused by tiles falling from building exterior walls are frequently reported in Taiwan. Humidity is an influential factor in tile deterioration but it is more difficult to measure the humidity inside a building structure than the humidity in an indoor environment. Therefore, a separable microsensor was developed in this study to measure the humidity of the cement mortar layer with a thickness of 1.5–2 cm inside the external wall of a building. 3D printing technology is used to produce an encapsulation box that can protect the sensor from damage caused by the concrete and cement mortar. The sensor is proven in this study to be capable of measuring temperature and humidity simultaneously and the measurement results are then used to analyze the influence of humidity on external wall tile deterioration.
Surviving a Dry Future: Abscisic Acid (ABA)-Mediated Plant Mechanisms for Conserving Water under Low Humidity

Science.gov (United States)

McAdam, Scott A. M.

2017-01-01

Angiosperms are able to respond rapidly to the first sign of dry conditions, a decrease in air humidity, more accurately described as an increase in the vapor pressure deficit between the leaf and the atmosphere (VPD), by abscisic acid (ABA)-mediated stomatal closure. The genes underlying this response offer valuable candidates for targeted selection of crop varieties with improved drought tolerance, a critical goal for current plant breeding programs, to maximize crop production in drier and increasingly marginalized environments, and meet the demands of a growing population in the face of a changing climate. Here, we review current understanding of the genetic mechanisms underpinning ABA-mediated stomatal closure, a key means for conserving water under dry conditions, examine how these mechanisms evolved, and discuss what remains to be investigated. PMID:29113039
Towards understanding the thermoanalysis of water sorption on lithium orthosilicate (Li{sub 4}SiO{sub 4})

Energy Technology Data Exchange (ETDEWEB)

Ortiz-Landeros, J. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico); Departamento de Ingenieria en Metalurgia y Materiales, ESIQIE, Instituto Politecnico Nacional, UPALM, Av. Instituto Politecnico Nacional s/n, CP 07738, Mexico DF (Mexico); Martinez-dlCruz, L. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico); Gomez-Yanez, C. [Departamento de Ingenieria en Metalurgia y Materiales, ESIQIE, Instituto Politecnico Nacional, UPALM, Av. Instituto Politecnico Nacional s/n, CP 07738, Mexico DF (Mexico); Pfeiffer, H., E-mail: pfeiffer@iim.unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, CP 04510, Del. Coyoacan, Mexico DF (Mexico)

2011-03-10

A systematic thermogravimetric study of hygroscopic and reactivity behaviors, at low temperatures of lithium orthosilicate (Li{sub 4}SiO{sub 4}), are presented. Li{sub 4}SiO{sub 4} sample was prepared by solid-state reaction and then treated at different temperature-humidity conditions. Li{sub 4}SiO{sub 4} samples previously treated under different temperature-humidity conditions were characterized by Fourier transform infrared spectroscopy and thermogravimetric analyses. Different processes, adsorption and absorption, take place between the Li{sub 4}SiO{sub 4} and water vapor. Absorbed water produces superficial hydroxylated species such as Si-OH and Li-OH. In addition, a kinetic analysis was performed, and the different water absorption activation enthalpies were calculated. It was found that activation enthalpy ({Delta}H) values decrease when the relative humidity is incremented, from 5528.6 J/mol to 2074.2 J/mol at relative humidity levels of 60% and 75% respectively. These results show the impact of different humidity and temperature conditions on the stability and/or chemical reactivity of Li{sub 4}SiO{sub 4}, if this ceramic is used in different application fields, such as carbon dioxide captor or as a breeder ceramic into the fusion reactors.
Mapping Annual Forest Cover in Sub-Humid and Semi-Arid Regions through Analysis of Landsat and PALSAR Imagery

Directory of Open Access Journals (Sweden)

Yuanwei Qin

2016-11-01

Full Text Available Accurately mapping the spatial distribution of forests in sub-humid to semi-arid regions over time is important for forest management but a challenging task. Relatively large uncertainties still exist in the spatial distribution of forests and forest changes in the sub-humid and semi-arid regions. Numerous publications have used either optical or synthetic aperture radar (SAR remote sensing imagery, but the resultant forest cover maps often have large errors. In this study, we propose a pixel- and rule-based algorithm to identify and map annual forests from 2007 to 2010 in Oklahoma, USA, a transitional region with various climates and landscapes, using the integration of the L-band Advanced Land Observation Satellite (ALOS PALSAR Fine Beam Dual Polarization (FBD mosaic dataset and Landsat images. The overall accuracy and Kappa coefficient of the PALSAR/Landsat forest map were about 88.2% and 0.75 in 2010, with the user and producer accuracy about 93.4% and 75.7%, based on the 3270 random ground plots collected in 2012 and 2013. Compared with the forest products from Japan Aerospace Exploration Agency (JAXA, National Land Cover Database (NLCD, Oklahoma Ecological Systems Map (OKESM and Oklahoma Forest Resource Assessment (OKFRA, the PALSAR/Landsat forest map showed great improvement. The area of the PALSAR/Landsat forest was about 40,149 km2 in 2010, which was close to the area from OKFRA (40,468 km2, but much larger than those from JAXA (32,403 km2 and NLCD (37,628 km2. We analyzed annual forest cover dynamics, and the results show extensive forest cover loss (2761 km2, 6.9% of the total forest area in 2010 and gain (3630 km2, 9.0% in southeast and central Oklahoma, and the total area of forests increased by 684 km2 from 2007 to 2010. This study clearly demonstrates the potential of data fusion between PALSAR and Landsat images for mapping annual forest cover dynamics in sub-humid to semi-arid regions, and the resultant forest maps would be
Calibration of Relative Humidity Devices in Low-pressure, Low-temperature CO2 Environment

Science.gov (United States)

Genzer, Maria; Polkko, Jouni; Nikkanen, Timo; Hieta, Maria; Harri, Ari-Matti

2017-04-01

Calibration of relative humidity devices requires in minimum two humidity points - dry (0%RH) and (near)saturation (95-100%RH) - over the expected operational temperature and pressure range of the device. In terrestrial applications these are relatively easy to achieve using for example N2 gas as dry medium, and water vapor saturation chambers for producing saturation and intermediate humidity points. But for example in applications intended for meteorological measurements on Mars there is a need to achieve at least dry and saturation points in low-temperature, low-pressure CO2 environment. We have developed a custom-made, small, relatively low-cost calibration chamber able to produce both dry points and saturation points in Martian range pressure CO2, in temperatures down to -70°C. The system utilizes a commercially available temperature chamber for temperature control, vacuum vessels and pumps. The main pressure vessel with the devices under test inside is placed inside the temperature chamber, and the pressure inside is controlled by pumps and manual valves and monitored with a commercial pressure reference with calibration traceable to national standards. Air, CO2, or if needed another gas like N2, is used for filling the vessel until the desired pressure is achieved. Another pressure vessel with a dedicated pressure pump is used as the saturation chamber. This vessel is placed in the room outside the temperature chamber, partly filled with water and used for achieving saturated water vapor in room-temperature low-pressure environment. The saturation chamber is connected to the main pressure vessel via valves. In this system dry point, low-pressure CO2 environment is achieved by filling the main pressure vessel with dry CO2 gas until the desired pressure is achieved. A constant flow of gas is maintained with the pump and valves and monitored with the pressure reference. The saturation point is then achieved by adding some water vapor from the saturation
Radon prevention coating in hot and humid environment

International Nuclear Information System (INIS)

Yang Yushan; Dong Faqin; Deng Yuequan; Qu Ruixue

2013-01-01

The radon prevention performance of a new self-made radon prevention coating was researched in the radon contamination provided by the releasing radon modules. With coating thickness of 0.8 mm, the radon mitigation efficiency in 1 # radon module concentration is optimal when the addition of defoaming agent is 0.3% (mass fraction). The radon mitigation efficiency increases with the coating thickness when the defoaming agent of 0.3% is added, but the radon mitigation efficiency tends to be stable as the coating thickness is more than 2.0 mm. The radon mitigation efficiency of radon prevention coating appended precipitated barium sulphate decreases obviously, and the addition of ash calcium, white cement and gesso don't decrease radon mitigation efficiency. The addition of white cement and gesso addition affects the radon prevention stability, while radon mitigation efficiency of radon prevention coating with ash calcium keeps a good performance. Under the hot and humid environment, the radon prevention coating still has good radon mitigation efficiency in 2 # radon module concentration. (authors)
Environmental and societal consequences of a possible CO/sub 2/-induced climate change. Volume II, Part 8. Impacts of rising atmospheric carbon dioxide levels on agricultural growing seasons and crop water use efficiencies

Energy Technology Data Exchange (ETDEWEB)

Newman, J. E.

1982-09-01

The researchable areas addressed relate to the possible impacts of climate change on agricultural growing seasons and crop adaptation responses on a global basis. The research activities proposed are divided into the following two main areas of investigation: anticipated climate change impacts on the physical environmental characteristics of the agricultural growing seasons and, the most probable food crop responses to the possible changes in atmospheric CO/sub 2/ levels in plant environments. The main physical environmental impacts considered are the changes in temperature, or more directly, thermal energy levels and the growing season evapotranspiration-precipitation balances. The resulting food crop, commercial forest and rangeland species response impacts addressed relate to potential geographical shifts in agricultural growing seasons as determined by the length in days of the frost free period, thermal energy changes and water balance changes. In addition, the interaction of possible changes in plant water use efficiencies during the growing season in relationship to changing atmospheric CO/sub 2/ concentrations, is also considered under the scenario of global warming due to increases in atmospheric CO/sub 2/ concentration. These proposed research investigations are followed by adaptive response evaluations.

40 CFR 89.326 - Engine intake air humidity measurement.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air... type of intake air supply, the humidity measurements must be made within the intake air supply system...
40 CFR 91.310 - Engine intake air humidity measurement.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply. Air...
40 CFR 90.310 - Engine intake air humidity measurement.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a) Humidity...
Leaf wetness distribution within a potato crop

Science.gov (United States)

Heusinkveld, B. G.

2010-07-01

The Netherlands has a mild maritime climate and therefore the major interest in leaf wetness is associated with foliar plant diseases. During moist micrometeorological conditions (i.e. dew, fog, rain), foliar fungal diseases may develop quickly and thereby destroy a crop quickly. Potato crop monocultures covering several hectares are especially vulnerable to such diseases. Therefore understanding and predicting leaf wetness in potato crops is crucial in crop disease control strategies. A field experiment was carried out in a large homogeneous potato crop in the Netherlands during the growing season of 2008. Two innovative sensor networks were installed as a 3 by 3 grid at 3 heights covering an area of about 2 hectares within two larger potato crops. One crop was located on a sandy soil and one crop on a sandy peat soil. In most cases leaf wetting starts in the top layer and then progresses downward. Leaf drying takes place in the same order after sunrise. A canopy dew simulation model was applied to simulate spatial leaf wetness distribution. The dew model is based on an energy balance model. The model can be run using information on the above-canopy wind speed, air temperature, humidity, net radiation and within canopy air temperature, humidity and soil moisture content and temperature conditions. Rainfall was accounted for by applying an interception model. The results of the dew model agreed well with the leaf wetness sensors if all local conditions were considered. The measurements show that the spatial correlation of leaf wetness decreases downward.
Update on {sup 13}C-labelling of plant materials through the use of walk-in growth chambers [Activities of the Soil and Water Management and Crop Nutrition Laboratory, Seibersdorf

Energy Technology Data Exchange (ETDEWEB)

Mayr, Leo; Resch, Christian; Weltin, Georg; Dercon, Gerd [Soil and Water Management and Crop Nutrition Laboratory, Joint FAO/IAEA Division for Nuclear Techniques in Food and Agriculture, Seibersdorf (Austria)

2014-07-15

In 2013, the Soil and Water Management & Crop Nutrition Laboratory installed a pair of walk-in growth chambers with an effective volume of about 12 m{sup 3} each. These growth chambers with temperature, relative humidity and carbon dioxide (CO{sub 2}) control, are being used within the framework of research activities for improving climate-smart agriculture in Member States.
A high sensitivity nanomaterial based SAW humidity sensor

Energy Technology Data Exchange (ETDEWEB)

Wu, T-T; Chou, T-H [Institute of Applied Mechanics, National Taiwan University, Taipei 106, Taiwan (China); Chen, Y-Y [Department of Mechanical Engineering, Tatung University, Taipei 104, Taiwan (China)], E-mail: wutt@ndt.iam.ntu.edu.tw

2008-04-21

In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128{sup 0}YX-LiNbO{sub 3} based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.
Heterogeneous nucleation for synthesis of sub-20nm ZnO nanopods and their application to optical humidity sensing.

Science.gov (United States)

Majithia, R; Ritter, S; Meissner, K E

2014-02-17

We present a novel method for colloidal synthesis of one-dimensional ZnO nanopods by heterogeneous nucleation on zero-dimensional ZnO nanoparticle 'seeds'. Ultra-small ZnO nanopods, multi-legged structures with sub-20 nm individual leg diameters, can be synthesized by hydrolysis of a Zn2+ precursor growth solution in presence of ∼4 nm ZnO seeds under hydrothermal conditions via microwave-assisted heating in as little as 20 min of reaction time. One-dimensional ZnO nanorods are initially generated in the reaction mixture by heterogeneous nucleation and growth along the [0001] direction of the ZnO crystal. Growth of one-dimensional nanorods subsequently yields to an 'attachment' and size-focusing phase where individual nanorods fuse together to form multi-legged nanopods having diameters ∼15 nm. ZnO nanopods exhibit broad orange-red defect-related photoluminescence in addition to a near-band edge emission at 373 nm when excited above the band-gap at 350 nm. The defect-related photoluminescence of the ZnO nanopods has been applied towards reversible optical humidity sensing at room temperature. The sensors demonstrated a linear response between 22% and 70% relative humidity with a 0.4% increase in optical intensity per % change in relative humidity. Due to their ultra-small dimensions, ZnO nanopods exhibit a large dynamic range and enhanced sensitivity to changes in ambient humidity, thus showcasing their ability as a platform for optical environmental sensing. Copyright © 2014 Elsevier B.V. All rights reserved.
Effect of temperature and humidity on post-gel shrinkage, cusp deformation, bond strength and shrinkage stress - Construction of a chamber to simulate the oral environment.

Science.gov (United States)

Bicalho, Aline Aredes; de Souza, Silas Júnior Boaventura; de Rosatto, Camila Maria Peres; Tantbirojn, Daranee; Versluis, Antheunis; Soares, Carlos José

2015-12-01

Evaluate the effect of environment on post-gel shrinkage (Shr), cuspal strains (CS), microtensile bond strength (μTBS), elastic modulus (E) and shrinkage stress in molars with large class II restorations. Sixty human molars received standardized Class II mesio-oclusal-distal cavity preparations. Restorations were made with two composites (CHA, Charisma Diamond, Heraus Kulzer and IPS Empress Direct, Ivoclar-Vivadent) using three environment conditions (22°C/50% humidity, 37°C/50% humidity and 37°C/90% humidity) simulated in custom developed chamber. Shr was measured using the strain gauge technique (n=10). CS was measured using strain gauges. Half of the teeth (n=5) were used to assess the elastic modulus (E) and Knoop hardness (KHN) at different depths using microhardness indentation. The other half (n=5) was used to measure the μTBS. The composites and environment conditions were simulated in a two-dimensional finite element analysis of a tooth restoration. Polymerization shrinkage was modeled using Shr data. The Shr, CS, μTBS, KHN and E data were statistically analyzed using two-way ANOVA and Tukey test (significance level: 0.05). Both composites had similar Shr, CS, μTBS and shrinkage stress. CHA had higher elastic modulus than IPS. Increasing temperature and humidity significantly increased Shr, CS and shrinkage stress. μTBS were similar for groups with lower humidity, irrespective of temperature, and higher with higher humidity. E and KHN were constant through the depth for CHA. E and KHN values were affected by environment only for IPS, mainly deeper in the cavity. Shrinkage stress at dentin/composite interface had high inverse correlation with μTBS. Shrinkage stress in enamel had high correlation with CS. Increasing temperature and humidity caused higher post-gel shrinkage and cusp deformation with higher shrinkage stresses in the tooth structure and tooth/restoration interface for both composites tested. The chamber developed for simulating the
Humidity Sensing in Drosophila.

Science.gov (United States)

Enjin, Anders; Zaharieva, Emanuela E; Frank, Dominic D; Mansourian, Suzan; Suh, Greg S B; Gallio, Marco; Stensmyr, Marcus C

2016-05-23

Environmental humidity influences the fitness and geographic distribution of all animals [1]. Insects in particular use humidity cues to navigate the environment, and previous work suggests the existence of specific sensory mechanisms to detect favorable humidity ranges [2-5]. Yet, the molecular and cellular basis of humidity sensing (hygrosensation) remains poorly understood. Here we describe genes and neurons necessary for hygrosensation in the vinegar fly Drosophila melanogaster. We find that members of the Drosophila genus display species-specific humidity preferences related to conditions in their native habitats. Using a simple behavioral assay, we find that the ionotropic receptors IR40a, IR93a, and IR25a are all required for humidity preference in D. melanogaster. Yet, whereas IR40a is selectively required for hygrosensory responses, IR93a and IR25a mediate both humidity and temperature preference. Consistent with this, the expression of IR93a and IR25a includes thermosensory neurons of the arista. In contrast, IR40a is excluded from the arista but is expressed (and required) in specialized neurons innervating pore-less sensilla of the sacculus, a unique invagination of the third antennal segment. Indeed, calcium imaging showed that IR40a neurons directly respond to changes in humidity, and IR40a knockdown or IR93a mutation reduced their responses to stimuli. Taken together, our results suggest that the preference for a specific humidity range depends on specialized sacculus neurons, and that the processing of environmental humidity can happen largely in parallel to that of temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.
Integrated crop livestock systems in sub-Saharan Africa: An option or an imperative?

OpenAIRE

Smith, J.W.; Naazie, A.; Larbi, A.; Agyemang, K.; Tarawali, S.

1997-01-01

Metadata only record Rapid growth of the human and livestock populations in sub-Saharan Africa is creating unprecedented increases in food and feed demands. These population pressures on a fixed landbase are likely to promote severe competition for resources and drive agriculture progressively towards intensification. Integrated crop livestock systems, already common in the highlands, are expected to evolve rapidly elsewhere. Research is required to develop technological alternatives which...
Adverse weather impacts on arable cropping systems

Science.gov (United States)

Gobin, Anne

2016-04-01

Damages due to extreme or adverse weather strongly depend on crop type, crop stage, soil conditions and management. The impact is largest during the sensitive periods of the farming calendar, and requires a modelling approach to capture the interactions between the crop, its environment and the occurrence of the meteorological event. The hypothesis is that extreme and adverse weather events can be quantified and subsequently incorporated in current crop models. Since crop development is driven by thermal time and photoperiod, a regional crop model was used to examine the likely frequency, magnitude and impacts of frost, drought, heat stress and waterlogging in relation to the cropping season and crop sensitive stages. Risk profiles and associated return levels were obtained by fitting generalized extreme value distributions to block maxima for air humidity, water balance and temperature variables. The risk profiles were subsequently confronted with yields and yield losses for the major arable crops in Belgium, notably winter wheat, winter barley, winter oilseed rape, sugar beet, potato and maize at the field (farm records) to regional scale (statistics). The average daily vapour pressure deficit (VPD) and reference evapotranspiration (ET0) during the growing season is significantly lower (p < 0.001) and has a higher variability before 1988 than after 1988. Distribution patterns of VPD and ET0 have relevant impacts on crop yields. The response to rising temperatures depends on the crop's capability to condition its microenvironment. Crops short of water close their stomata, lose their evaporative cooling potential and ultimately become susceptible to heat stress. Effects of heat stress therefore have to be combined with moisture availability such as the precipitation deficit or the soil water balance. Risks of combined heat and moisture deficit stress appear during the summer. These risks are subsequently related to crop damage. The methodology of defining
Nitrogen rhizodeposition from soybean (Glycine max) and its impact on nutrient budgets in two contrasting environments of the Guinean savannah zone of Nigeria

DEFF Research Database (Denmark)

Laberge, G.; Franke, A. C.; Ambus, Per

2009-01-01

Nitrogen (N) rhizodeposition by grain legumes such as soybean is potentially a large but neglected source of N in cropping systems of Sub-Saharan Africa. Field studies were conducted to measure soybean N rhizodeposition in two environments of the Guinean savannah of Nigeria using 15N leaf labelling...... removed. If residues were left in the field or recycled as manure after being fed to steers, soybean cultivation led to positive N budgets of up to +95 kg N ha−1. The role and potential of grain legumes as N purveyors have been underestimated in the past by neglecting the N contained...... techniques. The first site was located in Ibadan in the humid derived savannah. The second site was in Zaria in the drier Northern Guinean savannah. Soybean N rhizodeposition in the top 0.30 m of soil varied from 7.5 kg ha−1 on a diseased crop in Ibadan to 33 kg ha−1 in Zaria. More than two-thirds of soybean...
Impact of air exposure and surface chemistry on Li-Li7sub>La>3sub>Zr>2sub>O>12sub> interfacial resistance

Energy Technology Data Exchange (ETDEWEB)

Sharafi, Asma [Univ. of Michigan, Ann Arbor, MI (United States); Yu, Seungho [Univ. of Michigan, Ann Arbor, MI (United States); Naguib, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Marcus [Univ. of Michigan, Ann Arbor, MI (United States); Ma, Cheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nanda, Jagjit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chi, Maiofang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Siegel, Donald J. [Univ. of Michigan, Ann Arbor, MI (United States); Sakamoto, Jeff [Univ. of Michigan, Ann Arbor, MI (United States)

2017-06-15

Li7sub>La>3sub>Zr>2sub>O>12sub> (LLZO) is a promising solid-state electrolyte that could enable solid-state-batteries (SSB) employing metallic Li anodes. For a SSB to be viable, the stability and charge transfer kinetics at the Li–LLZO interface should foster facile plating and stripping of Li. Contrary to these goals, recent studies have reported high Li–LLZO interfacial resistance which was attributed to a contamination layer that forms upon exposure of LLZO to air. This study clarifies the mechanisms and consequences associated with air exposure of LLZO; additionally, strategies to minimize these effects are described. First-principles calculations reveal that LLZO readily reacts with humid air; the most favorable reaction pathway involves protonation of LLZO and formation of Li2CO3. X-ray photoelectron spectroscopy, scanning electron microscopy, Raman spectroscopy, and transmission electron microscopy were used to characterize the surface and subsurface chemistry of LLZO as a function of relative humidity and exposure time. Additionally, electrochemical impedance spectroscopy was used to measure the Li–LLZO interfacial resistance as a function of surface contamination. These data indicate that air exposure-induced contamination impacts the interfacial resistance significantly, when exposure time exceeds 24 h. The results of this study provide valuable insight into the sensitivity of LLZO to air and how the effects of air contamination can be reversed.
Effect of relative humidity on the tribological properties of hydrogenated diamond-like carbon films in a nitrogen environment

International Nuclear Information System (INIS)

Li Hongxuan; Xu Tao; Wang Chengbing; Chen Jianmin; Zhou Huidi; Liu Huiwen

2005-01-01

Hydrogenated diamond-like carbon (DLC) films were deposited on Si (100) wafers by a plasma enhanced chemical vapour deposition technique using CH 4 plus Ar as the feedstock. The friction and wear properties of the resulting films under different relative humidities, ranging from 5% to 100%, in a nitrogen environment, were measured using a ball-on-disc tribometer, with Si 3 N 4 balls as the counterparts. The friction surfaces of the films and Si 3 N 4 balls were observed on a scanning electron microscope, and investigated by x-ray photoelectron spectroscopy. The results showed that the friction coefficient increased continuously from 0.025 to 0.09 with increase in relative humidity from 5% to 100%, while the wear rate of the films sharply decreased and reached a minimum at a relative humidity of 40%, then it increased with further increase of the relative humidity. The interruption of the transferred carbon-rich layer on the Si 3 N 4 ball, and the friction-induced oxidation of the films at higher relative humidity were proposed as the main reasons for the increase in the friction coefficient. Moreover, the oxidation and hydrolysis of the Si 3 N 4 ball at higher relative humidity, leading to the formation of a tribochemical film, which mainly consists of silica gel, on the friction surface, are also thought to influence the friction and wear behaviour of the hydrogenated DLC films
Current-voltage characteristics of SnO{sub 2}-Co{sub 3}O{sub 4}-Cr{sub 2}O{sub 3}-Sb{sub 2}O{sub 5} ceramics

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Martinez, J A [Centro de Investigacion en Materiales Avanzados, S.C. (CIMAV), Alianza Norte 202, Parque de Investigacion e Innovacion Tecnologica (PIIT), Nueva Carretera Aeropuerto km. 10, Apodaca, Nuevo Leon, CP 66600 (Mexico); Glot, A B [Posgrado, Universidad Tecnologica de la Mixteca, Carretera Acatlima Km. 2.5, Huajuapan de Leon, Oaxaca, CP 69000 (Mexico); Gaponov, A V [Department of Radioelectronics, Dniepropetrovsk National University, Dniepropetrovsk 49050 (Ukraine); Hernandez, M B [Instituto de Mineria, Universidad Tecnologica de la Mixteca, Carretera Acatlima Km. 2.5, Huajuapan de Leon, Oaxaca, CP 69000 (Mexico); Guerrero-Paz, J, E-mail: josue.aguilar@cimav.edu.m [Particulate Materials Lab, Universidad Autonoma del Estado de Hidalgo, Pachuca, CP 42184 (Mexico)

2009-10-21

The effect of mechanical treatment in a planetary mill on the microstructure and electrical properties of tin dioxide based varistor ceramics in the system SnO{sub 2}-Co{sub 3}O{sub 4}-Cr{sub 2}O{sub 3}-Sb{sub 2}O{sub 5} sintered in the range 1150-1450 {sup 0}C was studied. The mechanical treatment leads to an increase in shrinkage, decrease in porosity, decrease in sample diameter, change in colour of the sintered samples from grey to black and enhancement of nonlinearity. For the sample sintered at 1350 {sup 0}C the mechanical treatment enhances the nonlinearity coefficient from 11 to 31 and decreases the electric field E{sub 1} (at 10{sup -3} A cm{sup -2}) from 3500 to 2800 V cm{sup -1}. The observed changes in physical properties are explained in terms of an additional size reduction of oxide particles and a better mixing of oxide powder followed by the formation of potential barriers at the grain boundaries throughout the whole sample. In spite of the low porosity, the low-field electrical conductivity of mechanically treated ceramics is significantly increased with the growth of relative humidity. A higher humidity sensitivity is found for mechanically treated ceramics with higher barrier height and higher nonlinearity coefficient.
MOISTURE HUMIDITY EQUILIBRIUM OF WOOD CHIPS FROM ENERGETIC CROPS

Directory of Open Access Journals (Sweden)

Jan Barwicki

2008-09-01

Full Text Available Processes occurring during storage of wood chips for energetic or furniture industry purposes were presented. As a result of carried out investigations, dependences of temperature and relative humidity changes of surrounding air were shown. Modified Henderson equation can be utilized for computer simulation of storing and drying processes concerning wood chips for energetic and furniture industry purposes. It reflects also obtained results from experiments carried out with above mentioned material. Using computer simulation program we can examine different wood chips storing conditions to avoid overheating and loss problems.
Effects of Humidity and Surfaces on the Melt Crystallization of Ibuprofen

Directory of Open Access Journals (Sweden)

Il Won Kim

2012-08-01

Full Text Available Melt crystallization of ibuprofen was studied to understand the effects of humidity and surfaces. The molecular self-assembly during the amorphous-to-crystal transformation was examined in terms of the nucleation and growth of the crystals. The crystallization was on Al, Au, and self-assembled monolayers with –CH3sub>, –OH, and –COOH functional groups. Effects of the humidity were studied at room temperature (18–20 °C with relative humidity 33%, 75%, and 100%. Effects of the surfaces were observed at −20 °C (relative humidity 36% to enable close monitoring with slower crystal growth. The nucleation time of ibuprofen was faster at high humidity conditions probably due to the local formation of the unfavorable ibuprofen melt/water interface. The crystal morphologies of ibuprofen were governed by the nature of the surfaces, and they could be associated with the growth kinetics by the Avrami equation. The current study demonstrated the effective control of the melt crystallization of ibuprofen through the melt/atmosphere and melt/surface interfaces.
Barley Breeding for Quality Improvement in Tunisia

African Journals Online (AJOL)

TOSHIBA

2012-11-06

Nov 6, 2012 ... sub-humid environment at Beja and a semi-arid one at Kef. Heading date ... State of art showed that barley was a main food crop in. North Africa for ... rably to many other food grains (wheat, rye, and oats) and played a .... rates both analysis of variance (ANOVA) and principal component analysis (PCA) into ...
Marginal cost curves for water footprint reduction in irrigated agriculture: guiding a cost-effective reduction of crop water consumption to a permit or benchmark level

Directory of Open Access Journals (Sweden)

A. D. Chukalla

2017-07-01

Full Text Available Reducing the water footprint (WF of the process of growing irrigated crops is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3  ha−1 per season or to a certain WF benchmark (expressed in m3  t−1 of crop. This paper aims to develop MCCs for WF reduction for a range of selected cases. AquaCrop, a soil-water-balance and crop-growth model, is used to estimate the effect of different management packages on evapotranspiration and crop yield and thus the WF of crop production. A management package is defined as a specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip; irrigation strategy (full or deficit irrigation; and mulching practice (no, organic or synthetic mulching. The annual average cost for each management package is estimated as the annualized capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy and labour. Different cases are considered, including three crops (maize, tomato and potato; four types of environment (humid in UK, sub-humid in Italy, semi-arid in Spain and arid in Israel; three hydrologic years (wet, normal and dry years and three soil types (loam, silty clay loam and sandy loam. For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF
Marginal cost curves for water footprint reduction in irrigated agriculture: guiding a cost-effective reduction of crop water consumption to a permit or benchmark level

Science.gov (United States)

Chukalla, Abebe D.; Krol, Maarten S.; Hoekstra, Arjen Y.

2017-07-01

Reducing the water footprint (WF) of the process of growing irrigated crops is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs) that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3 ha-1 per season) or to a certain WF benchmark (expressed in m3 t-1 of crop). This paper aims to develop MCCs for WF reduction for a range of selected cases. AquaCrop, a soil-water-balance and crop-growth model, is used to estimate the effect of different management packages on evapotranspiration and crop yield and thus the WF of crop production. A management package is defined as a specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip); irrigation strategy (full or deficit irrigation); and mulching practice (no, organic or synthetic mulching). The annual average cost for each management package is estimated as the annualized capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy and labour). Different cases are considered, including three crops (maize, tomato and potato); four types of environment (humid in UK, sub-humid in Italy, semi-arid in Spain and arid in Israel); three hydrologic years (wet, normal and dry years) and three soil types (loam, silty clay loam and sandy loam). For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF by reducing water

Formaldehyde measurements by Proton transfer reaction – Mass Spectrometry (PTR-MS: correction for humidity effects

Directory of Open Access Journals (Sweden)

A. Vlasenko

2010-08-01

Full Text Available Formaldehyde measurements can provide useful information about photochemical activity in ambient air, given that HCHO is formed via numerous oxidation processes. Proton transfer reaction mass spectrometry (PTR-MS is an online technique that allows measurement of VOCs at the sub-ppbv level with good time resolution. PTR-MS quantification of HCHO is hampered by the humidity dependence of the instrument sensitivity, with higher humidity leading to loss of PTR-MS signal. In this study we present an analytical, first principles approach to correct the PTR-MS HCHO signal according to the concentration of water vapor in sampled air. The results of the correction are validated by comparison of the PTR-MS results to those from a Hantzsch fluorescence monitor which does not have the same humidity dependence. Results are presented for an intercomparison made during a field campaign in rural Ontario at Environment Canada's Centre for Atmospheric Research Experiments.
Fabrication and Evaluation of a Graphene Oxide-Based Capacitive Humidity Sensor.

Science.gov (United States)

Feng, Jinfeng; Kang, Xiaoxu; Zuo, Qingyun; Yuan, Chao; Wang, Weijun; Zhao, Yuhang; Zhu, Limin; Lu, Hanwei; Chen, Juying

2016-03-01

In this study, a CMOS compatible capacitive humidity sensor structure was designed and fabricated on a 200 mm CMOS BEOL Line. A top Al interconnect layer was used as an electrode with a comb/serpent structure, and graphene oxide (GO) was used as sensing material. XRD analysis was done which shows that GO sensing material has a strong and sharp (002) peak at about 10.278°, whereas graphite has (002) peak at about 26°. Device level CV and IV curves were measured in mini-environments at different relative humidity (RH) level, and saturated salt solutions were used to build these mini-environments. To evaluate the potential value of GO material in humidity sensor applications, a prototype humidity sensor was designed and fabricated by integrating the sensor with a dedicated readout ASIC and display/calibration module. Measurements in different mini-environments show that the GO-based humidity sensor has higher sensitivity, faster recovery time and good linearity performance. Compared with a standard humidity sensor, the measured RH data of our prototype humidity sensor can match well that of the standard product.
Effect of temperature and humidity on electrical properties of organic semiconductor orange dye films deposited from solution

International Nuclear Information System (INIS)

Karimov, K.S.; Babadzhanov, A.; Turaeva, M.A.; Marupov, R.; Ahmed, M.M.; Khalid, F.A.; Khan, M.N.; Zakaullah, Kh.; Moiz, S.A.

2003-01-01

In this study the effect of temperature and humidity on electrical properties of organic semiconductor orange dye (OD) have been examined. Thin films of OD (C/sub 17/H/sub 17/N/sub 5/O/sub 2/) were deposited from 10 wt. % aqueous solution on gold and conductive glass (SnO/sub 2/) substrates. The films were grown at room temperature under normal gravity conditions, i.e., 1 g and in a spin coater up to an angular speed of 1000 RPM. Two different types of structures: surface Ga/OD/Au and sandwich AVOD/SnO/sub 2/ were fabricated and their DC and low frequency AC characteristics were evaluated for the temperature range 30-70 deg. C at ambient humidity of 50-80 %. It was observed that the sandwich structure of OD films show rectification behavior whilst the conductivity of all devices are temperature and humidity dependent. Observed room temperature activation energy for OD films was 0.30 eV which showed an increase up to 0.51 eV as a function of temperature. It was found that certain sandwich structures are more sensitive to humidity than others and the observed resistance to humidity ratio for Au/OD/Au was 5.4 whereas for Au/OD/Ga samples it was 5.0. (author)
Midday depression of CO/sub 2/ assimilation in leaves of Arbutus unedo L. : diurnal changes in photosynthetic capacity related to changes in temperature and humidity

Energy Technology Data Exchange (ETDEWEB)

Raschke, K.; Resemann, A.

1986-01-01

Parts of the attached leaves of the sclerophyllous shrub Arbutus unedo were subjected to simulated mediterranean days. Gas exchange was recorded in order to recognize the causes of the midday depression in CO/sub 2/ assimilation. Depressions could be induced in part of a leaf: they were local responses. The CO/sub 2/-saturation curves of photosynthesis, determined during the morning and afternoon maxima of CO/sub 2/ assimilation and during the minimum at midday, established that depressions in CO/sub 2/ assimilation were in one-half of the investigated cases totally caused by reversible reductions in the photosynthetic capacity of the leaves, and in other half almost totally caused by such reductions. There was no correlation between the water loss with the degree of reduction of the photosynthetic capacity. However, depressions occurred if an apparent threshold in the water-vapor pressure difference between leaf and air was exceeded. In another set of experiments, leaves were subjected to variations in temperature and humidity independent of the time of the day, under otherwise constant conditions. Photosynthetic capacity and stomatal conductance proved to be almost insensitive to changes in temperature (in a range extending from 20 to 37/sup 0/C) as long as the water vapor-pressure difference was held constant. If it was not, the rate of photosynthesis began to decline with increasing temperature after a threshold water-vapor pressure difference was exceeded. The position of the resulting apparent temperature optimum of photosynthesis depended on the humidity of the air. The authors suggest that the ability of A. unedo to respond to a dry atmosphere with a reversible reduction of its photosynthetic capacity (by a still unknown mechanism) is the result of a co-evolution with the development of a strong stomatal sensitivity to changes in humidity. 26 references, 14 figures.
Effects of acute supplementation of Panax ginseng on endurance running in a hot & humid environment

Science.gov (United States)

Ping, Fadzel Wong Chee; Keong, Chen Chee; Bandyopadhyay, Amit

2011-01-01

Background & objectives: Athletes in Malaysia need to perform in a hot and humid environment due to the climatic nature of the country. c0 hronic supplementation of Panax ginseng (PG) (a deciduous perennial plant belonging to the Araliaceae family) enhances physical performance. As the ergogenic effect of acute supplementation of PG on endurance performance has not been explored in the Malaysian population especially in a hot and humid condition this study was taken up. Methods: Nine heat adapted recreational runners (age : 25.4 ± 6.9 yr, body mass : 57.6 ± 8.4 kg; body height : 168.3 ± 7.6 cm) were recruited in this placebo-controlled double-blind randomized study. Subjects ingested 200 mg of PG one hour before the exercise test on treadmill at 70 per cent of their VO2max in a laboratory environment of 31 °C and 70 per cent relative humidity. They drank 3 ml/kg body weight of cool water every 20 min during the exercise to prevent adverse effects of dehydration. Blood samples were drawn every 20 min for the analysis of glucose, lactate, insulin and free fatty acids. Oxygen uptake was determined every 20 min while heart rate, body and skin temperatures, and ratings of perceived exertion (RPE) were recorded every 10 min during the trials. Results: Endurance running time to exhaustion did not differ between PG and placebo trials. Heart rate, skin temperature, core body temperature, oxygen uptake, RPE, plasma insulin, glucose, free fatty acid and lactate levels during the endurance exercise did not show any significant differences between the trials. Interpretation & conclusions: We conclude that acute supplementation of 200 mg of PG did not affect the endurance running performance of the heat-adapted male recreational runners in the heat. PMID:21321426
Humidity implications for populations of Drosophila suzukii (Diptera: Drosophilidae) on blueberry

Science.gov (United States)

Temperature and humidity affect insect physiology, survival, fecundity, reproductive status and behavior. Drosophila suzukii is an invasive pest of soft-skinned fruit and can cause severe economic losses in a wide range of susceptible crops. This study was conducted on blueberries to determine the e...
Optimization of multi-environment trials for genomic selection based on crop models.

Science.gov (United States)

Rincent, R; Kuhn, E; Monod, H; Oury, F-X; Rousset, M; Allard, V; Le Gouis, J

2017-08-01

We propose a statistical criterion to optimize multi-environment trials to predict genotype × environment interactions more efficiently, by combining crop growth models and genomic selection models. Genotype × environment interactions (GEI) are common in plant multi-environment trials (METs). In this context, models developed for genomic selection (GS) that refers to the use of genome-wide information for predicting breeding values of selection candidates need to be adapted. One promising way to increase prediction accuracy in various environments is to combine ecophysiological and genetic modelling thanks to crop growth models (CGM) incorporating genetic parameters. The efficiency of this approach relies on the quality of the parameter estimates, which depends on the environments composing this MET used for calibration. The objective of this study was to determine a method to optimize the set of environments composing the MET for estimating genetic parameters in this context. A criterion called OptiMET was defined to this aim, and was evaluated on simulated and real data, with the example of wheat phenology. The MET defined with OptiMET allowed estimating the genetic parameters with lower error, leading to higher QTL detection power and higher prediction accuracies. MET defined with OptiMET was on average more efficient than random MET composed of twice as many environments, in terms of quality of the parameter estimates. OptiMET is thus a valuable tool to determine optimal experimental conditions to best exploit MET and the phenotyping tools that are currently developed.
Potential of irradiation technology in horticultural crops

International Nuclear Information System (INIS)

Thomas, P.

1994-01-01

Fresh fruits and vegetables are living tissues which are subject to continuous change after harvest leading to senescence, cellular break-down and death. Post harvest losses in quality and quantity of horticultural crops result from physiological, pathological and physical processes, acting separately or in combination. Temperature management, maintenance of proper relative humidity of air, manipulation of storage temperature and exposing to ionizing radiation such as gamma rays enhance the shelf-life of horticultural crops
Do honeybees, Apis mellifera scutellata, regulate humidity in their nest?

Science.gov (United States)

Human, Hannelie; Nicolson, Sue W.; Dietemann, Vincent

2006-08-01

Honeybees are highly efficient at regulating the biophysical parameters of their hive according to colony needs. Thermoregulation has been the most extensively studied aspect of nest homeostasis. In contrast, little is known about how humidity is regulated in beehives, if at all. Although high humidity is necessary for brood development, regulation of this parameter by honeybee workers has not yet been demonstrated. In the past, humidity was measured too crudely for a regulation mechanism to be identified. We reassess this issue, using miniaturised data loggers that allow humidity measurements in natural situations and at several places in the nest. We present evidence that workers influence humidity in the hive. However, there are constraints on potential regulation mechanisms because humidity optima may vary in different locations of the nest. Humidity could also depend on variable external factors, such as water availability, which further impair the regulation. Moreover, there are trade-offs with the regulation of temperature and respiratory gas exchanges that can disrupt the establishment of optimal humidity levels. As a result, we argue that workers can only adjust humidity within sub-optimal limits.
Precipitation of HNbO{sub 3} at the Ti:LiNbO{sub 3} surface

Energy Technology Data Exchange (ETDEWEB)

Kalabin, Ivan E.; Grigorieva, Tatiana I.; Pokrovsky, Lev D.; Atuchin, Victor V

2004-03-30

The conditions of HNbO{sub 3} precipitation on the lithium niobate single-crystal and titanium diffused lithium niobate, LiNbO{sub 3} (LN) were studied. It has been shown, that the maximum of HNbO{sub 3} precipitation corresponds to the highest humidity of atmosphere at the annealing temperatures of 800-850 deg. C for 5-10 h. Moreover, the application of humid atmosphere during the annealing of LN at 600-850 deg. C does not ensure in full measure the lack of LiNb{sub 3}O{sub 8} precipitation.
A comparative study of humidity sensing and photocatalytic applications of pure and nickel (Ni)-doped WO{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Ramkumar, S. [Bannari Amman Institute of Technology, Department of Physics, Erode, Tamilnadu (India); Rajarajan, G. [Vidhya Mandhir Institute of Technology, Department of Physics, Erode, Tamilnadu (India)

2017-06-15

Nanocrystalline of pristine and nickel (Ni)-doped tungsten trioxide (WO{sub 3}) thin films was deposited by chemical bath deposition method. The concentrations of Ni ions were varied from 0 to 10 wt%. In order to improve the crystallinity of the films were annealed at 600 C for 2 h in the ambient atmosphere. X-ray diffraction results reveal that the WO{sub 3} doped with nickel crystallizes in monoclinic structure and the results are in good agreement with the standard JCPDS data (card no: 83-0951). AFM micrographs reveal that average grain size of about 27-39 nm for pure and Ni-doped WO{sub 3} thin films. In addition, the band gap of the Ni-doped WO{sub 3} nanostructures is facilely tunable by controlling the Ni contents. The humidity sensor setup was fabricated and measured for pure and Ni-doped WO{sub 3} thin film sensor with various level of RH (10-90%). The Ni-doped WO{sub 3} sensor showed fast response and high sensitivity than pure WO{sub 3}. The photocatalytic activities of the films were evaluated by degradation of methyl orange, methylene blue and phenol in an aqueous solution under visible light irradiation. The photocatalytic activity of WO{sub 3} nanostructures could be remarkably enhanced by doping the Ni impurity. (orig.)
Fabrication and Evaluation of a Graphene Oxide-Based Capacitive Humidity Sensor

Directory of Open Access Journals (Sweden)

Jinfeng Feng

2016-03-01

Full Text Available In this study, a CMOS compatible capacitive humidity sensor structure was designed and fabricated on a 200 mm CMOS BEOL Line. A top Al interconnect layer was used as an electrode with a comb/serpent structure, and graphene oxide (GO was used as sensing material. XRD analysis was done which shows that GO sensing material has a strong and sharp (002 peak at about 10.278°, whereas graphite has (002 peak at about 26°. Device level CV and IV curves were measured in mini-environments at different relative humidity (RH level, and saturated salt solutions were used to build these mini-environments. To evaluate the potential value of GO material in humidity sensor applications, a prototype humidity sensor was designed and fabricated by integrating the sensor with a dedicated readout ASIC and display/calibration module. Measurements in different mini-environments show that the GO-based humidity sensor has higher sensitivity, faster recovery time and good linearity performance. Compared with a standard humidity sensor, the measured RH data of our prototype humidity sensor can match well that of the standard product.
Crop epigenetics and the molecular hardware of genotype x environment interactions

Directory of Open Access Journals (Sweden)

Graham John King

2015-11-01

Full Text Available Crop plants encounter thermal environments which fluctuate on a diurnal and seasonal basis. Future climate resilient cultivars will need to respond to thermal profiles reflecting more variable conditions, and harness plasticity that involves regulation of epigenetic processes and complex genomic regulatory networks. Compartmentalisation within plant cells insulates the genomic central processing unit within the interphase nucleus. This review addresses the properties of the chromatin hardware in which the genome is embedded, focusing on the biophysical and thermodynamic properties of DNA, histones and nucleosomes. It explores the consequences of thermal and ionic variation on the biophysical behaviour of epigenetic marks such as DNA cytosine methylation (5mC, and histone variants such as H2A.Z, and how these contribute to maintenance of chromatin integrity in the nucleus, while enabling specific subsets of genes to be regulated. Information is drawn from theoretical molecular in vitro studies as well as model and crop plants and incorporates recent insights into the role epigenetic processes play in mediating between environmental signals and genomic regulation. A preliminary speculative framework is outlined, based on the evidence of what appears a cohesive set of interactions at molecular, biophysical and electrostatic level between the various components contributing to chromatin conformation and dynamics. It proposes that within plant nuclei, general and localised ionic homeostasis plays an important role in maintaining chromatin conformation, whilst maintaining complex genomic regulation that involve specific patterns of epigenetic marks. More generally, reversible changes in DNA methylation appear to be consistent with the ability of nuclear chromatin to manage variation in external ionic and temperature environment. Whilst tentative, this framework provides scope to develop experimental approaches to understand in greater detail the
Genomic Selection in Multi-environment Crop Trials.

Science.gov (United States)

Oakey, Helena; Cullis, Brian; Thompson, Robin; Comadran, Jordi; Halpin, Claire; Waugh, Robbie

2016-05-03

Genomic selection in crop breeding introduces modeling challenges not found in animal studies. These include the need to accommodate replicate plants for each line, consider spatial variation in field trials, address line by environment interactions, and capture nonadditive effects. Here, we propose a flexible single-stage genomic selection approach that resolves these issues. Our linear mixed model incorporates spatial variation through environment-specific terms, and also randomization-based design terms. It considers marker, and marker by environment interactions using ridge regression best linear unbiased prediction to extend genomic selection to multiple environments. Since the approach uses the raw data from line replicates, the line genetic variation is partitioned into marker and nonmarker residual genetic variation (i.e., additive and nonadditive effects). This results in a more precise estimate of marker genetic effects. Using barley height data from trials, in 2 different years, of up to 477 cultivars, we demonstrate that our new genomic selection model improves predictions compared to current models. Analyzing single trials revealed improvements in predictive ability of up to 5.7%. For the multiple environment trial (MET) model, combining both year trials improved predictive ability up to 11.4% compared to a single environment analysis. Benefits were significant even when fewer markers were used. Compared to a single-year standard model run with 3490 markers, our partitioned MET model achieved the same predictive ability using between 500 and 1000 markers depending on the trial. Our approach can be used to increase accuracy and confidence in the selection of the best lines for breeding and/or, to reduce costs by using fewer markers. Copyright © 2016 Oakey et al.
Indoor air humidity, air quality, and health - An overview.

Science.gov (United States)

Wolkoff, Peder

2018-04-01

There is a long-standing dispute about indoor air humidity and perceived indoor air quality (IAQ) and associated health effects. Complaints about sensory irritation in eyes and upper airways are generally among top-two symptoms together with the perception "dry air" in office environments. This calls for an integrated analysis of indoor air humidity and eye and airway health effects. This overview has reviewed the literature about the effects of extended exposure to low humidity on perceived IAQ, sensory irritation symptoms in eyes and airways, work performance, sleep quality, virus survival, and voice disruption. Elevation of the indoor air humidity may positively impact perceived IAQ, eye symptomatology, and possibly work performance in the office environment; however, mice inhalation studies do not show exacerbation of sensory irritation in the airways by low humidity. Elevated humidified indoor air appears to reduce nasal symptoms in patients suffering from obstructive apnea syndrome, while no clear improvement on voice production has been identified, except for those with vocal fatigue. Both low and high RH, and perhaps even better absolute humidity (water vapor), favors transmission and survival of influenza virus in many studies, but the relationship between temperature, humidity, and the virus and aerosol dynamics is complex, which in the end depends on the individual virus type and its physical/chemical properties. Dry and humid air perception continues to be reported in offices and in residential areas, despite the IAQ parameter "dry air" (or "wet/humid air") is semantically misleading, because a sensory organ for humidity is non-existing in humans. This IAQ parameter appears to reflect different perceptions among other odor, dustiness, and possibly exacerbated by desiccation effect of low air humidity. It is salient to distinguish between indoor air humidity (relative or absolute) near the breathing and ocular zone and phenomena caused by moisture
Bioenergy Sorghum Crop Model Predicts VPD-Limited Transpiration Traits Enhance Biomass Yield in Water-Limited Environments.

Science.gov (United States)

Truong, Sandra K; McCormick, Ryan F; Mullet, John E

2017-01-01

Bioenergy sorghum is targeted for production in water-limited annual cropland therefore traits that improve plant water capture, water use efficiency, and resilience to water deficit are necessary to maximize productivity. A crop modeling framework, APSIM, was adapted to predict the growth and biomass yield of energy sorghum and to identify potentially useful traits for crop improvement. APSIM simulations of energy sorghum development and biomass accumulation replicated results from field experiments across multiple years, patterns of rainfall, and irrigation schemes. Modeling showed that energy sorghum's long duration of vegetative growth increased water capture and biomass yield by ~30% compared to short season crops in a water-limited production region. Additionally, APSIM was extended to enable modeling of VPD-limited transpiration traits that reduce crop water use under high vapor pressure deficits (VPDs). The response of transpiration rate to increasing VPD was modeled as a linear response until a VPD threshold was reached, at which the slope of the response decreases, representing a range of responses to VPD observed in sorghum germplasm. Simulation results indicated that the VPD-limited transpiration trait is most beneficial in hot and dry regions of production where crops are exposed to extended periods without rainfall during the season or to a terminal drought. In these environments, slower but more efficient transpiration increases biomass yield and prevents or delays the exhaustion of soil water and onset of leaf senescence. The VPD-limited transpiration responses observed in sorghum germplasm increased biomass accumulation by 20% in years with lower summer rainfall, and the ability to drastically reduce transpiration under high VPD conditions could increase biomass by 6% on average across all years. This work indicates that the productivity and resilience of bioenergy sorghum grown in water-limited environments could be further enhanced by development
Experimental studies on the uptake of technetium-99 to terrestrial crops

Energy Technology Data Exchange (ETDEWEB)

Brown, Joanne; Ewers, Leon [Centre for Radiation, Chemical and Environmental Hazards, Public Health England (United Kingdom)

2014-07-01

Technetium-99 has been dispersed in the environment from many sources such as nuclear weapons testing, releases from medical or industrial processes, nuclear power plants and nuclear fuel processing facilities. The pertechnetate ion, {sup 99}TcO{sub 4}{sup -} is the form produced during the nuclear fuel cycle and the most likely to be released into the environment. A recent review published by Public Health England (formerly the Health Protection Agency) found that the availability for the root uptake of technetium into crops depends on whether the technetium is in a chemically non-reduced more plant available form, such as TcO{sub 4}{sup -} or a chemically reduced less plant available form, such as TcO{sub 2}. Based on the review, generic soil to crop transfer factor (TF) values for use in non-site specific UK based radiological assessments were proposed, with the TF value for the reduced form of technetium in crops around a factor of 10 lower than that for the non-reduced form. The implications of the use of different TF values on the activity concentrations in crops and animal products predicted by PHE's food chain model, FARMLAND, for both routine and accidental release situations were explored. Recommendations on the best choice of TF values for use in the model have been given for a range of contamination scenarios. A small scale experimental study has been carried out to provide further evidence that the generic assumption made on the difference between soil-crop TF values for non-reduced and reduced forms of technetium is valid. The study was also designed to establish likely time periods over which the chemical reduction of technetium takes place and to provide additional soil-crop TF values for use in UK based radiological assessments. Soil to crop TFs for crops harvested from loam and peat soils up to 4 months after contamination are about a factor of 10 higher than those seen in soil contaminated more than a year previously, indicating that the
Coping mechanisms for crop plants in drought-prone environments.

Science.gov (United States)

Neumann, Peter M

2008-05-01

Drought is a major limitation to plant productivity. Various options are available for increasing water availability and sustaining growth of crop plants in drought-prone environments. After a general introduction to the problems of water availability, this review focuses on a critical evaluation of recent progress in unravelling mechanisms for modifying plant growth responses to drought. Investigations of key regulatory mechanisms integrating plant growth responses to water deficits at the whole-organism, cellular and genomic levels continue to provide novel and exiting research findings. For example, recent reports contradict the widespread conception that root-derived abscisic acid is necessarily involved in signalling for stomatal and shoot-growth responses to soil water deficits. The findings bring into question the theoretical basis for alternate-side root-irrigation techniques. Similarly, recent reports indicate that increased ABA production or increased aquaporin expression did not lead to improved drought resistance. Other reports have concerned key genes and proteins involved in regulation of flowering (FT), vegetative growth (DELLA), leaf senescence (IPT) and desiccation tolerance (LEA). Introgression of such genes, with suitable promoters, can greatly impact on whole-plant responses to drought. Further developments could facilitate the introduction by breeders of new crop varieties with growth physiologies tailored to improved field performance under drought. Parallel efforts to encourage the introduction of supplementary irrigation with water made available by improved conservation measures and by sea- or brackish-water desalination, will probably provide comprehensive solutions to coping with drought-prone environments.
Integrated production of warm season grasses and agroforestry for biomass production

Energy Technology Data Exchange (ETDEWEB)

Samson, R.; Omielan, J. [Resource Efficient Agricultural Production-Canada, Ste, Anne de Bellevue, Quebec (Canada); Girouard, P.; Henning, J. [McGill Univ., Ste. Anne de Bellevue, Quebec (Canada)

1993-12-31

Increased research on C{sub 3} and C{sub 4} perennial biomass crops is generating a significant amount of information on the potential of these crops to produce large quantities of low cost biomass. In many parts of North America it appears that both C{sub 3} and C{sub 4} species are limited by water availability particularly on marginal soils. In much of North America, rainfall is exceeded by evaporation. High transpiration rates by fast growing trees and rainfall interception by the canopy appear to indicate that this can further exacerbate the problem of water availability. C{sub 4} perennial grasses appear to have distinct advantages over C{sub 3} species planted in monoculture systems particularly on marginal soils. C{sub 4} grasses historically predominated over much of the land that is now available for biomass production because of their adaptation to low humidity environments and periods of low soil moisture. The planting of short rotation forestry (SRF) species in an energy agroforestry system is proposed as an alternative production strategy which could potentially alleviate many of the problems associated with SRF monocultures. Energy agroforestry would be complementary to both production of conventional farm crops and C{sub 4} perennial biomass crops because of beneficial microclimatic effects.
Short Oligonucleotides Aligned in Stretched Humid Matrix: Secondary DNA Structure in Poly(vinyl alcohol) Environment

KAUST Repository

Hanczyc, Piotr

2012-04-24

We report that short, synthetic, double- as well as single-stranded DNA can be aligned in stretched humid poly(vinyl alcohol) (PVA) matrix, and the secondary structure (nucleobase orientation) can be characterized with linear dichroism (LD) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.4 nm) were investigated with respect to structural properties in the gel-like polymer environment. The DNA conformation as a function of relative humidity reveals a strong dependence of helical structure of DNA on PVA hydration level, results of relevance for nanotechnical studies of DNA-based supramolecular systems. Also, the PVA gel could provide possibilities to test models for nucleic acid interactions and distribution in cell contexts, including structural stability of genetic material in the cell and PVA-packaging for gene delivery. A method by which duplex oligonucleotides, with sequences designed to provide specific binding sites, become amenable to polarized-light spectroscopy opens up new possibilities for studying structure in DNA complexes with small adduct molecules as well as proteins. © 2012 American Chemical Society.

An experimental and mathematical modeling study comparing the reactivity and burnout of pulverized coal in air (O{sub 2}/N{sub 2}) and oxyfuel (O{sub 2}/CO{sub 2}) environments

Energy Technology Data Exchange (ETDEWEB)

Liza Elliott; Yinghui Liu; Bart Buhre; Jennifer Martin; Raj Gupta; Terry Wall [University of Newcastle, Callaghan, NSW (Australia). Cooperative Research Centre for Coal in Sustainable Development, Chemical Engineering

2005-07-01

Carbon dioxide in flue gas from conventional combustion processes is present as a dilute gas. CO{sub 2} capture is more easily achieved from a concentrated CO{sub 2} stream, which can be achieved by firing fuels with oxygen to obtain a sequestration ready gas stream, called oxy-fuel combustion. In this technology, the oxygen stream is usually diluted by recycled flue gas (RFG), so that the coal burns in an environment which is primarily O{sub 2}/CO{sub 2}. A size cut of a number of pulverised coals were devolatalised in N{sub 2} and CO{sub 2}. These sized coals were also combusted in a drop-tube furnace in an O{sub 2}/N{sub 2} environment simulating air combustion, and O{sub 2}/CO{sub 2} simulating oxyfuel combustion, with varying O{sub 2} levels from 3 to 30% v/v. Measurements of the extent of devolatilisation and coal burnout were completed. The detailed data provided for one coal indicated that the devolatilisation process in the O{sub 2}/CO{sub 2} environments is influenced by char gasification, and the char reaction rates are fitted better by a fractional order rate than first order in oxygen. Combustion rates in the oxyfuel environment were slightly higher. Estimates of the burnout for furnaces retrofitted from air to oxyfuel indicate that a better burnout can be expected. These trends were common for all coals. 14 refs., 4 figs., 5 tabs.
Evaluation of the dose to man in relation to the behavior of tritium from irrigation water in agricultural crops

International Nuclear Information System (INIS)

Kirchmann, R.; Bruwaene, R. van; Koch, G.; Grauby, A.; Delmas, J.; Athalye, V.

1977-01-01

A research program on the transfer of tritium from the irrigation water in the soil-plant environment provides valuable ecological information on the effects of tritium releases from nuclear installations under temperate humide and mediterranean climatic conditions. Field studies are carried out on experimental plots by spraying the crops with irrigation water contaminated with tritium on a single dose, the reference level chosen is 1 nCi/litre. The following crops are investigated: prairie, rye-grass, potato, pea, barley, carrot and sugarbeet as temperate region cultures, and vineyard, olive-tree and orange-tree as mediterranean cultures. Soil and plants samples are collected for radioassay to determine the tritium incorporation in tissue water and organic matter fractions. The tritium activity in these crops after harvest is correlated to the level of radiation dose received through human diet [fr
Humidity evolution (breathing effect) in enclosures with electronics

DEFF Research Database (Denmark)

Hygum, Morten Arnfeldt; Popok, Vladimir

2015-01-01

Packaging and enclosures used for protecting power electronics operating outdoors are designed to withstand the local climatic and environmental changes. Hermetic enclosures are expensive and therefore other solutions for protecting the electronics from a harsh environment are required. One...... of the dangerous parameters is high humidity of air. Moisture can inevitable reach the electronics either due to diffusion through the wall of an enclosure or small holes, which are designed for electrical or other connections. A driving force for humid air movement is the temperature difference between...... the operating electronics and the surrounding environment. This temperature, thus, gives rise to a natural convection, which we also refer to as breathing. Robust and intelligent enclosure designs must account for this breathing as it can significantly change the humidity distribution in the enclosure...
Composition and fate of mine- and smelter-derived particles in soils of humid subtropical and hot semi-arid areas

Energy Technology Data Exchange (ETDEWEB)

Ettler, Vojtěch, E-mail: ettler@natur.cuni.cz [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Johan, Zdenek [BRGM, Avenue Claude Guillemin, 45082 Orléans Cedex 2 (France); Kříbek, Bohdan; Veselovský, František [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Mihaljevič, Martin [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Vaněk, Aleš; Penížek, Vít [Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Praha 6 (Czech Republic); Majer, Vladimír [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Sracek, Ondra [Department of Geology, Faculty of Science, Palacký University in Olomouc, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Mapani, Ben; Kamona, Fred [Department of Geology, Faculty of Science, University of Namibia, Private Bag 13301, Windhoek (Namibia); Nyambe, Imasiku [University of Zambia, School of Mines, P. O. Box 32 379, Lusaka (Zambia)

2016-09-01

We studied the heavy mineral fraction, separated from mining- and smelter-affected topsoils, from both a humid subtropical area (Mufulira, Zambian Copperbelt) and a hot semi-arid area (Tsumeb, Namibia). High concentrations of metal(loid)s were detected in the studied soils: up to 1450 mg As kg{sup −1}, 8980 mg Cu kg{sup −1}, 4640 mg Pb kg{sup −1}, 2620 mg Zn kg{sup −1}. A combination of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM/EDS), and electron probe microanalysis (EPMA) helped to identify the phases forming individual metal(loid)-bearing particles. Whereas spherical particles originate from the smelting and flue gas cleaning processes, angular particles have either geogenic origins or they are windblown from the mining operations and mine waste disposal sites. Sulphides from ores and mine tailings often exhibit weathering rims in contrast to smelter-derived high-temperature sulphides (chalcocite [Cu{sub 2}S], digenite [Cu{sub 9}S{sub 5}], covellite [CuS], non-stoichiometric quenched Cu–Fe–S phases). Soils from humid subtropical areas exhibit higher available concentrations of metal(loids), and higher frequencies of weathering features (especially for copper-bearing oxides such as delafossite [Cu{sup 1+} Fe{sup 3+} O{sub 2}]) are observed. In contrast, metal(loid)s are efficiently retained in semi-arid soils, where a high proportion of non-weathered smelter slag particles and low-solubility Ca–Cu–Pb arsenates occur. Our results indicate that compared to semi-arid areas (where inorganic contaminants were rather immobile in soils despite their high concentrations) a higher potential risk exists for agriculture in mine- and smelter-affected humid subtropical areas (where metal(loid) contaminants can be highly available for the uptake by crops). - Highlights: • Mining- and smelter-derived particles identified in subtropical and semi-arid soils • Sulphides, oxides, and metal-bearing arsenates most frequently encountered �
Sensitivity of honeybee hygroreceptors to slow humidity changes and temporal humidity variation detected in high resolution by mobile measurements.

Science.gov (United States)

Tichy, Harald; Kallina, Wolfgang

2014-01-01

The moist cell and the dry cell on the antenna of the male honeybee were exposed to humidities slowly rising and falling at rates between -1.5%/s and +1.5%/s and at varying amplitudes in the 10 to 90% humidity range. The two cells respond to these slow humidity oscillations with oscillations in impulse frequency which depend not only on instantaneous humidity but also on the rate with which humidity changes. The impulse frequency of each cell was plotted as a function of these two parameters and regression planes were fitted to the data points of single oscillation periods. The regression slopes, which estimate sensitivity, rose with the amplitude of humidity oscillations. During large-amplitude oscillations, moist and dry cell sensitivity for instantaneous humidity and its rate of change was high. During small-amplitude oscillations, their sensitivity for both parameters was low, less exactly reflecting humidity fluctuations. Nothing is known about the spatial and temporal humidity variations a honeybee may encounter when flying through natural environments. Microclimatic parameters (absolute humidity, temperature, wind speed) were measured from an automobile traveling through different landscapes of Lower Austria. Landscape type affected extremes and mean values of humidity. Differences between peaks and troughs of humidity fluctuations were generally smaller in open grassy fields or deciduous forests than in edge habitats or forest openings. Overall, fluctuation amplitudes were small. In this part of the stimulus range, hygroreceptor sensitivity is not optimal for encoding instantaneous humidity and the rate of humidity change. It seems that honeybee's hygroreceptors are specialized for detecting large-amplitude fluctuations that are relevant for a specific behavior, namely, maintaining a sufficiently stable state of water balance. The results suggest that optimal sensitivity of both hygroreceptors is shaped not only by humidity oscillation amplitudes but also
Temporal changes in climatic variables and their impact on crop yields in southwestern China.

Science.gov (United States)

Liu, Hong-Bin; Gou, Yu; Wang, Hong-Ye; Li, Hong-Mei; Wu, Wei

2014-08-01

Knowledge of variability in climatic variables changes and its impact on crop yields is important for farmers and policy makers, especially in southwestern China where rainfed agriculture is dominant. In the current study, six climatic parameters (mean temperature, rainfall, relative humidity, sunshine hours, temperature difference, and rainy days) and aggregated yields of three main crops (rice: Oryza sativa L., oilseed rape: Brassica napus L., and tobacco: Nicotiana tabacum L.) during 1985-2010 were collected and analyzed for Chongqing-a large agricultural municipality of China. Climatic variables changes were detected by Mann-Kendall test. Increased mean temperature and temperature difference and decreased relative humidity were found in annual and oilseed rape growth time series (Pchanges in climatic variables in this region. Yield of rice increased with rainfall (Pclimatic variables to crop yields. Temperature difference and sunshine hours had higher direct and indirect effects via other climatic variables on yields of rice and tobacco. Mean temperature, relative humidity, rainy days, and temperature difference had higher direct and indirect effects via others on yield of oilseed rape.
A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

DEFF Research Database (Denmark)

Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

2015-01-01

accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...
Ambient humidity and the skin: the impact of air humidity in healthy and diseased states.

Science.gov (United States)

Goad, N; Gawkrodger, D J

2016-08-01

Humidity, along with other climatic factors such as temperature and ultraviolet radiation, can have an important impact on the skin. Limited data suggest that external humidity influences the water content of the stratum corneum. An online literature search was conducted through Pub-Med using combinations of the following keywords: skin, skin disease, humidity, dermatoses, dermatitis, eczema, and mist. Publications included in this review were limited to (i) studies in humans or animals, (ii) publications showing relevance to the field of dermatology, (iii) studies published in English and (iv) publications discussing humidity as an independent influence on skin function. Studies examining environmental factors as composite influences on skin health are only included where the impact of humidity on the skin is also explored in isolation of other environmental factors. A formal systematic review was not feasible for this topic due to the heterogeneity of the available research. Epidemiological studies indicated an increase in eczema with low internal (indoors) humidity and an increase in eczema with external high humidity. Other studies suggest that symptoms of dry skin appear with low humidity internal air-conditioned environments. Murine studies determined that low humidity caused a number of changes in the skin, including the impairment of the desquamation process. Studies in humans demonstrated a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness. Intervention with a humidifying mist increased the water content of the stratum corneum. Conversely, there is some evidence that low humidity conditions can actually improve the barrier function of the skin. Ambient relative humidity has an impact on a range of parameters involved in skin health but the literature is inconclusive. Further
Comparison of techniques for the measurement of skin temperature during exercise in a hot, humid environment

Directory of Open Access Journals (Sweden)

Brian K McFarlin

2014-10-01

Full Text Available Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual’s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes for the measurement of peripheral (bicep and central (abdominal skin temperature. Young men and women (N=30 were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO 2 max of cycling in a hot (39±2°C, humid (45±5% RH environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5 were a better index of wired than was thermal imaging (3.5, For the bicep skin temperature the limits of agreement was similar between data loggers (1.9 and thermal (1.9, suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35ºC, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects
Modelling approach for the rainfall erosivity index in sub-humid urban areas in northern Algeria

Science.gov (United States)

Touaibia, I.; Abderrahmane Guenim, N.; Touaibia, B.

2014-09-01

This work presents an approach for storm water erosivity index modelling in the absence of measurement in an urban area, in a sub-humid climate. In torrential storms, floods, loaded with sediments, obstruct storm water drainage. With the aim of estimating the amount of sediment that can be deposited on a stretch of road, adjacent to the study area, the erosivity index is determined from a count of 744 rain showers recorded over a period of 19 years. The Universal Soil Loss Equation (USLE) of Wischmeier and Smith is applied, where only the index of erosivity is calculated; it is based on the intensity of the rain starting the process of erosion in the basin. Functional relations are required between this factor and the explanatory variables. A power type regression model is reached, making it possible to bring a decision-making aid in absences of measurements.
Modelling approach for the rainfall erosivity index in sub-humid urban areas in northern Algeria

Directory of Open Access Journals (Sweden)

I. Touaibia

2014-09-01

Full Text Available This work presents an approach for storm water erosivity index modelling in the absence of measurement in an urban area, in a sub-humid climate. In torrential storms, floods, loaded with sediments, obstruct storm water drainage. With the aim of estimating the amount of sediment that can be deposited on a stretch of road, adjacent to the study area, the erosivity index is determined from a count of 744 rain showers recorded over a period of 19 years. The Universal Soil Loss Equation (USLE of Wischmeier and Smith is applied, where only the index of erosivity is calculated; it is based on the intensity of the rain starting the process of erosion in the basin. Functional relations are required between this factor and the explanatory variables. A power type regression model is reached, making it possible to bring a decision-making aid in absences of measurements.
Health symptoms in relation to temperature, humidity, and self-reported perceptions of climate in New York City residential environments

Science.gov (United States)

Quinn, Ashlinn; Shaman, Jeffrey

2017-07-01

Little monitoring has been conducted of temperature and humidity inside homes despite the fact that these conditions may be relevant to health outcomes. Previous studies have observed associations between self-reported perceptions of the indoor environment and health. Here, we investigate associations between measured temperature and humidity, perceptions of indoor environmental conditions, and health symptoms in a sample of New York City apartments. We measured temperature and humidity in 40 New York City apartments during summer and winter seasons and collected survey data from the households' residents. Health outcomes of interest were (1) sleep quality, (2) symptoms of heat illness (summer season), and (3) symptoms of respiratory viral infection (winter season). Using mixed-effects logistic regression models, we investigated associations between the perceptions, symptoms, and measured conditions in each season. Perceptions of indoor temperature were significantly associated with measured temperature in both the summer and the winter, with a stronger association in the summer season. Sleep quality was inversely related to measured and perceived indoor temperature in the summer season only. Heat illness symptoms were associated with perceived, but not measured, temperature in the summer season. We did not find an association between any measured or perceived condition and cases of respiratory infection in the winter season. Although limited in size, the results of this study reveal that indoor temperature may impact sleep quality, and that thermal perceptions of the indoor environment may indicate vulnerability to heat illness. These are both important avenues for further investigation.
40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity and... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX intake...
Estimating Major Crop Water Productivity at Neyshabour Basin and Optimize Crop Area

Directory of Open Access Journals (Sweden)

Yavar Pourmohamad

2017-06-01

Full Text Available Introductionin current situation when world is facing massive population, producing enough food and adequate income for people is a big challenge specifically for governors. This challenge gets even harder in recent decades, due to global population growth which was projected to increase to 7.8 billion in 2025. Agriculture as the only industry that has ability to produce food is consuming 90 percent of fresh water globally. Despite of increasing for food demand, appropriate agricultural land and fresh water resources are restricted. To solve this problem, one is to increase water productivity which can be obtain by irrigation. Iran is not only exempted from this situation but also has more critical situation due to its dry climate and inappropriate precipitation distribution spatially and temporally, also uneven distribution of population which is concentrate in small area. The only reasonable solution by considering water resources limitation and also restricted crop area is changing crop pattern to reach maximum or at least same amount of income by using same or less amount of water. The purpose of this study is to assess financial water productivity and optimize farmer’s income by changing in each crop acreage at basin and sub-basin level with no extra groundwater withdrawals, also in order to repair the damages which has enforce to groundwater resources during last decades a scenario of using only 80percent of renewable water were applied and crop area were optimize to provide maximum or same income for farmers. Materials and methodsThe Neyshabour basin is located in northeast of Iran, the total geographical area of basin is 73,000 km2 consisting of 41,000 km2 plain and the rest of basin is mountains. This Basin is a part of Kalshoor catchment that is located in southern part of Binaloud heights and northeast of KavirMarkazi. In this study whole Neyshabour basin were divided into 199 sub-basins based on pervious study.Based on official
Crop classification and mapping based on Sentinel missions data in cloud environment

Science.gov (United States)

Lavreniuk, M. S.; Kussul, N.; Shelestov, A.; Vasiliev, V.

2017-12-01

Availability of high resolution satellite imagery (Sentinel-1/2/3, Landsat) over large territories opens new opportunities in agricultural monitoring. In particular, it becomes feasible to solve crop classification and crop mapping task at country and regional scale using time series of heterogenous satellite imagery. But in this case, we face with the problem of Big Data. Dealing with time series of high resolution (10 m) multispectral imagery we need to download huge volumes of data and then process them. The solution is to move "processing chain" closer to data itself to drastically shorten time for data transfer. One more advantage of such approach is the possibility to parallelize data processing workflow and efficiently implement machine learning algorithms. This could be done with cloud platform where Sentinel imagery are stored. In this study, we investigate usability and efficiency of two different cloud platforms Amazon and Google for crop classification and crop mapping problems. Two pilot areas were investigated - Ukraine and England. Google provides user friendly environment Google Earth Engine for Earth observation applications with a lot of data processing and machine learning tools already deployed. At the same time with Amazon one gets much more flexibility in implementation of his own workflow. Detailed analysis of pros and cons will be done in the presentation.
Impact of storage environment on the efficacy of hermetic storage bags.

Science.gov (United States)

Lane, Brett; Woloshuk, Charles

2017-05-01

Small hermetic bags (50 and 100 kg capacities) used by smallholder farmers in several African countries have proven to be a low-cost solution for preventing storage losses due to insects. The complexity of postharvest practices and the need for ideal drying conditions, especially in the Sub-Sahara, has led to questions about the efficacy of the hermetic bags for controlling spoilage by fungi and the potential for mycotoxin accumulation. This study compared the effects of environmental temperature and relative humidity at two locations (Indiana and Arkansas) on dry maize (14% moisture content) in woven polypropylene bags and Purdue Improved Crop Storage (PICS) hermetic bags. Temperature and relative humidity data loggers placed in the middle of each bag provided profiles of environmental influences on stored grain at the two locations. The results indicated that the PICS bags prevented moisture penetration over the three-month storage period. In contrast, maize in the woven bags increased in moisture content. For both bag types, no evidence was obtained indicating the spread of Aspergillus flavus from colonized maize to adjacent non-colonized maize. However, other storage fungi did increase during storage. The number of infected kernels did not increase in the PICS bags, but the numbers in the woven bags increased significantly. The warmer environment in Arkansas resulted in significantly higher insect populations in the woven bags than in Indiana. Insects in the PICS bags remained low at both locations. This study demonstrates that the PICS hermetic bags are effective at blocking the effects of external humidity fluctuations as well as the spread of fungi to non-infected kernels.
Analysis of humidity effects on growth and production of glasshouse fruit vegetables

NARCIS (Netherlands)

Bakker, J.C.

1991-01-01

Air humidity is a climate factor that can modify final yield and quality of crops through its impact on processes with a short as well as with a long response time. This thesis primarily deals with the long term responses of growth and production of glasshouse cucumber, tomato, sweet pepper and
Projected climate change impacts and short term predictions on staple crops in Sub-Saharan Africa

Science.gov (United States)

Mereu, V.; Spano, D.; Gallo, A.; Carboni, G.

2013-12-01

Agriculture in Sub-Saharan Africa (SSA) drives the economy of many African countries and it is mainly rain-fed agriculture used for subsistence. Increasing temperatures, changed precipitation patterns and more frequent droughts may lead to a substantial decrease of crop yields. The projected impacts of future climate change on agriculture are expected to be significant and extensive in the SSA due to the shortening of the growing seasons and the increasing of water-stress risk. Differences in Agro-Ecological Zones and geographical characteristics of SSA influence the diverse impacts of climate change, which can greatly differ across the continent and within countries. The vulnerability of African Countries to climate change is aggravated by the low adaptive capacity of the continent, due to the increasing of its population, the widespread poverty, and other social factors. In this contest, the assessment of climate change impact on agricultural sector has a particular interest to stakeholder and policy makers, in order to identify specific agricultural sectors and Agro-Ecological Zones that could be more vulnerable to changes in climatic conditions and to develop the most appropriate policies to cope with these threats. For these reasons, the evaluation of climate change impacts for key crops in SSA was made exploring climate uncertainty and focusing on short period monitoring, which is particularly useful for food security and risk management analysis. The DSSAT-CSM (Decision Support System for Agrotechnology Transfer - Cropping System Model) software, version 4.5 was used for the analysis. Crop simulation models included in DSSAT-CSM are tools that allow to simulate physiological process of crop growth, development and production, by combining genetic crop characteristics and environmental (soil and weather) conditions. For each selected crop, the models were used, after a parameterization phase, to evaluate climate change impacts on crop phenology and production
Sub-hectare crop area mapped wall-to-wall in Tigray Ethiopia with HEC processing of WorldView sub-meter panchromatic image texture

Science.gov (United States)

Neigh, C. S. R.; Carroll, M.; Wooten, M.; McCarty, J. L.; Powell, B.; Husak, G. J.; Enenkel, M.; Hain, C.

2017-12-01

Global food production in the developing world occurs within sub-hectare fields that are difficult to identify with moderate resolution satellite imagery. Knowledge about the distribution of these fields is critical in food security programs. We developed a semi-automated image segmentation approach using wall-to-wall sub-meter imagery with high-end computing (HEC) to map crop area (CA) throughout Tigray, Ethiopia that encompasses over 41,000 km2. Our approach tested multiple HEC processing streams to reduce processing time and minimize mapping error. We applied multiple resolution smoothing kernels to capture differences in land surface texture associated to CA. Typically, very-small fields (mean big-data methodology to extract wall-to-wall CA for other regions of the world that have very-small agriculture fields with similar image texture.
EDITORIAL: Humidity sensors Humidity sensors

Science.gov (United States)

Regtien, Paul P. L.

2012-01-01

All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be

Transfer of radionuclides from the environment to crops and agricultural products

International Nuclear Information System (INIS)

Delmas, J.

1977-01-01

The transfer rates of 90 Sr, 137 Cs, 54 Mn, 65 Zn, 60 Co and 22 Na from the irrigation water to different crops, determined by means of experimental models, depend on the mode of conveyance, the water quality, and on the type and portion of the plant in question. In certain cases, the resulting contamination to foodstuffs undergoing irrigation is higher than that of the water. The contamination level of the consumed product also depends on the food processing technology. The monitoring of crops and converted agricultural products is thus of great use for the knowledge of the radiological state of the site. Measurements taken in the environment show that this contamination is very slight. This monitoring is very well accepted by farmers and managers of food product conversion companies, because it provides proof of the quality of their products from the radiological standpoint [fr
Nitrous oxide and carbon dioxide emissions from monoculture and rotational cropping of corn, soybean and winter wheat

Energy Technology Data Exchange (ETDEWEB)

Drury, C.F.; Yang, X.M.; Reynolds, W.D. [Agriculture and Agri-Food Canada, Harrow, ON (Canada); McLaughlin, N.B. [Agriculture and Agri-Food Canada, Ottawa, ON (Canada). Eastern Cereal and Oilseed Research Centre

2008-04-15

Nitrous oxide (N{sub 2}O) and carbon dioxide (CO{sub 2}) emissions from agricultural soils are influenced by different types of crops, the amounts and types of nitrogen fertilizers used, and the soil and climatic conditions under which the crops are grown. Crop rotation also has an impact on N{sub 2}O emissions, as the crop residues used to supply soluble carbon to soil biota often differ from the crops being grown. This study compared the influence of crops and residues from preceding crops on N{sub 2}O and CO{sub 2} emissions from monoculture crops of soybeans, corn, and winter wheat at a site in Ontario. The phases of different rotations were compared with 2- and 3-year crop rotations. Results of the study showed that N{sub 2}O emissions were approximately 3.1 to 5.1 times higher in monoculture corn than levels observed in winter wheat or soybean crops. When corn followed corn, average N{sub 2}O emissions twice as high as when corn followed soybeans, and 65 per cent higher than when corn followed winter wheat. The higher levels of both N{sub 2}O and CO{sub 2} were attributed to higher inorganic nitrogen (N) application rates in corn crops. In the corn phase, CO{sub 2} levels were higher when the preceding crop was winter wheat. It was concluded that N{sub 2}O and CO{sub 2} emissions from agricultural fields are influenced by both current and preceding crops, a fact which should be considered and accounted for in estimates and forecasts of agricultural greenhouse gas (GHG) emissions. 21 refs., 3 tabs., 10 figs.
PAIR INFLUENCE OF WIND SPEED AND MEAN RADIANT TEMPERATURE ON OUTDOOR THERMAL COMFORT OF HUMID TROPICAL ENVIRONMENT

Directory of Open Access Journals (Sweden)

Sangkertadi Sangkertadi

2016-01-01

Full Text Available The purposes of this article is to explore knowledge of outdoor thermal comfort in humid tropical environment for urban activities especially for people in walking activity, and those who stationary/seated with moderate action. It will be characterized the pair influence of wind speed and radiant temperature on the outdoor thermal comfort. Many of researchers stated that those two microclimate variables give significant role on outdoor thermal comfort in tropical humid area. Outdoor Tropical Comfort (OTC model was used for simulation in this study. The model output is comfort scale that refers on ASHRAE definition. The model consists of two regression equations with variables of air temperature, globe temperature, wind speed, humidity and body posture, for two types of activity: walking and seated. From the results it can be stated that there is significant role of wind speed to reduce mean radiant temperature and globe temperature, when the velocity is elevated from 0.5 m/s to 2 m/s. However, the wind has not play significant role when the speed is changed from 2 m/s to 3.5 m/s. The results of the study may inspire us to implement effectiveness of electrical-fan equipment for outdoor space in order to get optimum wind speed, coupled with optimum design of shading devices to minimize radiant temperature for thermal comfort.
Regulatory challenges for GM crops in developing economies: the African experience.

Science.gov (United States)

Nang'ayo, Francis; Simiyu-Wafukho, Stella; Oikeh, Sylvester O

2014-12-01

Globally, transgenic or genetically modified (GM) crops are considered regulated products that are subject to regulatory oversight during trans-boundary movement, testing and environmental release. In Africa, regulations for transgenic crops are based on the outcomes of the historic Earth Summit Conference held in Rio, Brazil two decades ago, namely, the adoption of the Convention on Biological Diversity (CBD) and the subsequent adoption of the Cartagena Protocol on Biosafety. To exploit the potential benefits of transgenic crops while safeguarding the potential risks on human health and environment, most African countries have signed and ratified the CBD and the Cartagena Protocol on Biosafety. Consequently, these countries are required to take appropriate legal, administrative and other measures to ensure that the handling and utilization of living modified organisms are undertaken in a manner that reduces the risks to humans and the environment. These countries are also expected to provide regulatory oversight on transgenic crops through functional national biosafety frameworks (NBFs). While in principle this approach is ideal, NBFs in most African countries are steeped in a host of policy, legal and operational challenges that appear to be at cross-purposes with the noble efforts of seeking to access, test and deliver promising GM crops for use by resource-limited farmers in Africa. In this paper we discuss the regulatory challenges faced during the development and commercialization of GM crops based on experiences from countries in Sub-Saharan Africa.
C{sub 60} AS A PROBE FOR ASTROPHYSICAL ENVIRONMENTS

Energy Technology Data Exchange (ETDEWEB)

Brieva, A. C.; Jäger, C.; Huisken, F. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Gredel, R.; Henning, T., E-mail: aab01@alumni.aber.ac.uk [Max Planck Institute for Astronomy (MPIA), Königstuhl 17, D-69117 Heidelberg (Germany)

2016-08-01

The C{sub 60} molecule has been recently detected in a wide range of astrophysical environments through its four active intramolecular vibrational modes ( T {sub 1u}) near 18.9, 17.4, 8.5, and 7.0 μ m. The strengths of the mid-infrared emission bands have been used to infer astrophysical conditions in the fullerene-rich regions. Widely varying values of the relative intrinsic strengths (RIS) of these four bands are reported in laboratory and theoretical papers, which impedes the derivation of the excitation mechanism of C{sub 60} in the astrophysical sources. The spectroscopic analysis of the C{sub 60} samples produced with our method delivers highly reproducible RIS values of 100, 25 ± 1, 26 ± 1 and 40 ± 4. A comparison of the inferred C{sub 60} emission band strengths with the astrophysical data shows that the observed strengths cannot be explained in terms of fluorescent or thermal emission alone. The large range in the observed 17.4 μ m/18.9 μ m emission ratios indicates that either the emission bands contain significant contributions from emitters other than C{sub 60}, or that the population distribution among the C{sub 60} vibrational modes is affected by physical processes other than thermal or UV excitation, such as chemo-luminescence from nascent C{sub 60} or possibly Poincaré fluorescence resulting from an inverse internal energy conversion. We have carefully analyzed the effect of the weakly active fundamental modes and second order modes in the mid-infrared spectrum of C{sub 60}, and propose that neutral C{sub 60} is the carrier of the unidentified emission band at 6.49 μ m which has been observed in fullerene-rich environments.
Is Obsidian Hydration Dating Affected by Relative Humidity?

Science.gov (United States)

Friedman, I.; Trembour, F.W.; Smith, G.I.; Smith, F.L.

1994-01-01

Experiments carried out under temperatures and relative humidities that approximate ambient conditions show that the rate of hydration of obsidian is a function of the relative humidity, as well as of previously established variables of temperature and obsidian chemical composition. Measurements of the relative humidity of soil at 25 sites and at depths of between 0.01 and 2 m below ground show that in most soil environments, at depths below about 0.25 m, the relative humidity is constant at 100%. We have found that the thickness of the hydrated layer developed on obsidian outcrops exposed to the sun and to relative humidities of 30-90% is similar to that formed on other portions of the outcrop that were shielded from the sun and exposed to a relative humidity of approximately 100%. Surface samples of obsidian exposed to solar heating should hydrate more rapidly than samples buried in the ground. However, the effect of the lower mean relative humidity experiences by surface samples tends to compensate for the elevated temperature, which may explain why obsidian hydration ages of surface samples usually approximate those derived from buried samples.
The effects of ozone and NO{sub x} on the deterioration of calcareous stone

Energy Technology Data Exchange (ETDEWEB)

Massey, S.W. [Building Research Establishment Ltd, Garston, Watford (United Kingdom)

1999-03-09

This paper looks at the changes in urban air quality and the effect on building materials with particular regard to their deterioration arising from pollution due to vehicles. The paper aims to review basic information on the likely effect of NO{sub x} and ozone on calcareous building materials (limestone, marble, dolomite, calcareous cemented sandstone) by examining experimental and fieldwork relating to the principle reaction of the oxidation of the sulphite to sulphate. NO{sub 2} is only one of many possible oxidants present in the urban and rural environment. A brief synopsis of the effects of other oxidants and inhibitors is given along with a review of the processes involved in aqueous phase oxidation, which seems to be the phase where the reactions take place. Controlling factors in the reaction and oxidation of sulphite to sulphate are the type and porosity of the stone, the level of humidity, the nature of the oxidants and to a lesser extent the presence of other extraneous reactants, e.g. metal oxides, chlorine and ammonia salts. For freshly cut stone unpolished marble is much less reactive than porous limestone and the degree of activity has different relative humidity thresholds. Reaction of the stone with the gaseous compounds occurs during the process of absorption onto the surface. The oxidation is accelerated at the gas-water interface by the presence of NO{sub x}, and seems to depend on the NO{sub 2} component but it is clear that NO{sub x} is only one of many possible oxidants in the urban and rural environments. Correlation studies of the damage to stone materials are unlikely to pick up the effects of NO{sub x} due to the nature of their duration and the rather transient nature of the appearance and removal of nitrates on the stone. Presence of other oxidants and catalysts such as H{sub 2}O{sub 2}, O{sub 2} (catalysed by Fe{sup 3+} and Mn{sup 2+}), OH, HSO{sub 5}{sup -}, SO{sub 4}{sup 2-}, O{sub 3}, HO{sub 2}, NO{sub 2}{sup -}, NO{sub 3}, O{sub
The effects of ozone and NO{sub x} on the deterioration of calcareous stone

Energy Technology Data Exchange (ETDEWEB)

Massey, S.W. [Building Research Establishment Ltd., Garston, Watford (United Kingdom)

1999-03-09

This paper looks at the changes in urban air quality and the effect on building materials with particular regard to their deterioration arising from pollution due to vehicles. The paper aims to review basic information on the likely effect of NO{sub x} and ozone on calcareous building materials (limestone, marble, dolomite, calcareous cemented sandstone) by examining experimental and fieldwork relating to the principle reaction of the oxidation of the sulphite to sulphate. NO{sub 2} is only one of many possible oxidants present in the urban and rural environment. A brief synopsis of the effects of other oxidants and inhibitors is given along with a review of the processes involved in aqueous phase oxidation, which seems to be the phase where the reactions take place. Controlling factors in the reaction and oxidation of sulphite to sulphate are the type and porosity of the stone, the level of humidity, the nature of the oxidants and to a lesser extent the presence of other extraneous reactants, e.g. metal oxides, chlorine and ammonia salts. For freshly cut stone unpolished marble is much less reactive than porous limestone and the degree of activity has different relative humidity thresholds. Reaction of the stone with the gaseous compounds occurs during the process of absorption onto the surface. The oxidation is accelerated at the gas-water interface by the presence of NO{sub x}, and seems to depend on the NO{sub 2} component but it is clear that NO{sub x} is only one of many possible oxidants in the urban and rural environments. Correlation studies of the damage to stone materials are unlikely to pick up the effects of NO{sub x} due to the nature of their duration and the rather transient nature of the appearance and removal of nitrates on the stone. Presence of other oxidants and catalysts such as H{sub 2}O{sub 2}, O{sub 2} (catalysed by Fe{sup 3+} and Mn{sup 2+}), OH, HSO{sub 5}{sup -}, SO{sub 4}{sup 2-}, O{sub 3}, HO{sub 2}, NO{sub 2}{sup -}, NO{sub 3}, O{sub
Combining Multi-Agent Systems and Wireless Sensor Networks for Monitoring Crop Irrigation

Directory of Open Access Journals (Sweden)

Gabriel Villarrubia

2017-08-01

Full Text Available Monitoring mechanisms that ensure efficient crop growth are essential on many farms, especially in certain areas of the planet where water is scarce. Most farmers must assume the high cost of the required equipment in order to be able to streamline natural resources on their farms. Considering that many farmers cannot afford to install this equipment, it is necessary to look for more effective solutions that would be cheaper to implement. The objective of this study is to build virtual organizations of agents that can communicate between each other while monitoring crops. A low cost sensor architecture allows farmers to monitor and optimize the growth of their crops by streamlining the amount of resources the crops need at every moment. Since the hardware has limited processing and communication capabilities, our approach uses the PANGEA architecture to overcome this limitation. Specifically, we will design a system that is capable of collecting heterogeneous information from its environment, using sensors for temperature, solar radiation, humidity, pH, moisture and wind. A major outcome of our approach is that our solution is able to merge heterogeneous data from sensors and produce a response adapted to the context. In order to validate the proposed system, we present a case study in which farmers are provided with a tool that allows us to monitor the condition of crops on a TV screen using a low cost device.
Feasibility of cuphea as a new oilseed crop to climate and soil environments

Science.gov (United States)

Cuphea, a new oilseed crop rich in medium-chain fatty acids (C8:0 to C14:0), may serve as a renewable, biodegradable source of oil for lubricants, motor oil, and aircraft fuel. Impacts of climate and soil environment on cuphea growth and development are not well understood. The objective of this stu...
Management and conservation of tropical acid soils for sustainable crop production. Proceedings of a consultants meeting

International Nuclear Information System (INIS)

2000-06-01

Forests of the tropics are invaluable ecosystems of global, regional and local importance, particularly in terms of protection and conservation of biodiversity and water resources. The indiscriminate conversion of tropical forests into agricultural land as a result of intense human activities - logging and modem shifting cultivation - continues to cause soil erosion and degradation. However, the acid savannahs of the world, such as the cerrado of Brazil, the Llanos in Venezuela and Colombia, the savannahs of Africa, and the largely anthropic savannahs of tropical Asia, encompass vast areas of potentially arable land. The acid soils of the savannahs are mostly considered marginal because of low inherent fertility and susceptibility to rapid degradation. These constraints for agricultural development are exacerbated by the poverty of new settlers who try to cultivate such areas after deforestation. Low- or minimum-input systems are not sustainable on these tropical acid soils but, with sufficient investment and adequate technologies, they can be highly productive. Thus, there is a need to develop management practices for sustainable agricultural production systems on such savannah acid soils. The Soil and Water Management and Crop Nutrition Sub-programme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture strongly supports an integrated approach to soil, water and nutrient management within cropping systems. In this context, nuclear and related techniques can be used to better understand the processes and factors influencing the productivity of agricultural production systems, and improve them through the use of better soil, water and nutrient management practices. A panel of experts actively engaged in field projects on acid soils of savannah agro-ecosystems in the humid and sub-humid tropics convened in March 1999 in Vienna to review and discuss recent research progress, along the following main lines of investigation: (i) utilization of
Heat strain evaluation of overt and covert body armour in a hot and humid environment.

Science.gov (United States)

Pyke, Andrew J; Costello, Joseph T; Stewart, Ian B

2015-03-01

The aim of this study was to elucidate the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. Eight healthy males walked on a treadmill for 120 min at 22% of their heart rate reserve in a climate chamber simulating 31 °C (60%RH) wearing either no armour (control), overt or covert PBA in addition to a security guard uniform, in a randomised controlled crossover design. No significant difference between conditions at the end of each trial was observed in core temperature, heart rate or skin temperature (P > 0.05). Covert PBA produced a significantly greater amount of body mass change (-1.81 ± 0.44%) compared to control (-1.07 ± 0.38%, P = 0.009) and overt conditions (-1.27 ± 0.44%, P = 0.025). Although a greater change in body mass was observed after the covert PBA trial; based on the physiological outcome measures recorded, the heat strain encountered while wearing lightweight, non-military overt or covert PBA was negligible compared to no PBA. The wearing of bullet proof vests or body armour is a requirement of personnel engaged in a wide range of occupations including police, security, customs and even journalists in theatres of war. This randomised controlled crossover study is the first to examine the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. We conclude that the heat strain encountered while wearing both overt and covert lightweight, non-military PBA was negligible compared to no PBA. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.
The Response of Durum Wheat to the Preceding Crop in a Mediterranean Environment

Directory of Open Access Journals (Sweden)

Laura Ercoli

2014-01-01

Full Text Available Crop sequence is an important management practice that may affect durum wheat (Triticum durum Desf. production. Field research was conducted in 2007-2008 and 2008-2009 seasons in a rain-fed cold Mediterranean environment to examine the impact of the preceding crops alfalfa (Medicago sativa L., maize (Zea mays L., sunflower (Helianthus annuus L., and bread wheat (Triticum aestivum L. on yield and N uptake of four durum wheat varieties. The response of grain yield of durum wheat to the preceding crop was high in 2007-2008 and was absent in the 2008-2009 season, because of the heavy rainfall that negatively impacted establishment, vegetative growth, and grain yield of durum wheat due to waterlogging. In the first season, durum wheat grain yield was highest following alfalfa, and was 33% lower following wheat. The yield increase of durum wheat following alfalfa was mainly due to an increased number of spikes per unit area and number of kernels per spike, while the yield decrease following wheat was mainly due to a reduction of spike number per unit area. Variety growth habit and performance did not affect the response to preceding crop and varieties ranked in the order Levante > Saragolla = Svevo > Normanno.
ORCHIDEE-CROP (v0), a new process-based agro-land surface model

NARCIS (Netherlands)

Wu, X.; Vuichard, N.; Ciais, P.; Moors, E.J.; Jans, W.; Elbers, J.

2016-01-01

The response of crops to changing climate and atmospheric CO2sub> concentration ([CO2sub>]) could have large effects on food production, and impact carbon, water, and energy fluxes, causing feedbacks to the climate. To simulate the response of temperate crops to changing climate and
Humidity sensing in insects-from ecology to neural processing.

Science.gov (United States)

Enjin, Anders

2017-12-01

Humidity is an omnipresent climatic factor that influences the fitness, reproductive behavior and geographic distribution of animals. Insects in particular use humidity cues to navigate the environment. Although the sensory neurons of this elusive sense were first described more than fifty years ago, the transduction mechanism of humidity sensing (hygrosensation) remains unknown. Recent work has uncovered some of the key molecules involved, opening up for novel approaches to study hygrosensory transduction. In this review, I will discuss this progress made toward understanding hygrosensation in insects. Copyright © 2017 Elsevier Inc. All rights reserved.
Crop rotation impact on soil quality

International Nuclear Information System (INIS)

Aziz, I.; Ashraf, M.; Mahmood, T.; Islam, K.R.

2011-01-01

Management systems influence soil quality over time. A study was carried out on Van meter farm of the Ohio State University South Centers at Piketon Ohio, USA to evaluate the impact of crop rotations on soil quality from 2002 to 2007. The crop rotations comprised of continuous corn (CC), corn-soybean (CS) and corn-soybean-wheat-cowpea (CSW). Ten soil cores were collected at 0-7.5, 7.5-15, 15-22.5 and 22.5-30 cm, and sieved. The soils were analyzed for total microbial biomass (C/sub mic/), basal respiration (BR) and specific maintenance respiration (qCO/sub 2/) rates as biological quality indicators; total organic carbon (TC), active carbon (AC) and total nitrogen (TN) as chemical quality indicators; and aggregate stability (AS), particulate organic matter (POM) and total porosity (ft) as physical quality parameters at different depths of soil. The inductive additive approach based on the concept of 'higher value of any soil property except ft, a better indicator of soil quality' was used to calculate the biological (SBQ), chemical (SCQ), physical (SPQ) and composite soil quality (SQI) indices. The results showed that crop rotation had significant impact on C/sub mic/, BR, qCO/sub 2/, TC, AC, TN, AS and POM except ft at different depths of soil. The CSW had higher soil quality values than CC and CS. The values of selected soil quality properties under the given crop rotation significantly decreased except ft with increasing soil depth. The SBQ (23%), SCQ (16%), SPQ (7%) and SQI (15%) improved under CSW over time. The results imply that multiple cropping systems could be more effective for maintaining and enhancing soil quality than sole-cropping systems. (author)
Sweet potato weevil (Cylas formicarius) incidence in the humid lowlands of Papua New Guinea

NARCIS (Netherlands)

Powell, K.S.; Hartemink, A.E.; Eganae, J.F.; Walo, C.; Poloma, S.

2001-01-01

Sweet potato is the main staple crop in PNG and this paper presents a study from the humid lowlands of the Morobe Province. Three experiments were carried out at two locations (Hobu and Unitech) to evaluate the effect of inorganic fertiliser inputs and fallow vegetation on the incidence of sweet
Fatigue Crack Propagation Behavior of RC Beams Strengthened with CFRP under High Temperature and High Humidity Environment

Directory of Open Access Journals (Sweden)

Dongyang Li

2017-01-01

Full Text Available Numerical and experimental methods were applied to investigate fatigue crack propagation behavior of reinforced concrete (RC beams strengthened with a new type carbon fiber reinforced polymer (CFRP named as carbon fiber laminate (CFL subjected to hot-wet environment. J-integral of a central crack in the strengthened beam under three-point bending load was calculated by ABAQUS. In finite element model, simulation of CFL-concrete interface was based on the bilinear cohesive zone model under hot-wet environment and indoor atmosphere. And, then, fatigue crack propagation tests were carried out under high temperature and high humidity (50°C, 95% R · H environment pretreatment and indoor atmosphere (23°C, 78% R · H to obtain a-N curves and crack propagation rate, da/dN, of the strengthened beams. Paris-Erdogan formula was developed based on the numerical analysis and environmental fatigue tests.
Laboratory observations of temperature and humidity dependencies of nucleation and growth rates of sub-3 nm particles

Science.gov (United States)

Yu, Huan; Dai, Liang; Zhao, Yi; Kanawade, Vijay P.; Tripathi, Sachchida N.; Ge, Xinlei; Chen, Mindong; Lee, Shan-Hu

2017-02-01

Temperature and relative humidity (RH) are the most important thermodynamic parameters in aerosol formation, yet laboratory studies of nucleation and growth dependencies on temperature and RH are lacking. Here we report the experimentally observed temperature and RH dependences of sulfuric acid aerosol nucleation and growth. Experiments were performed in a flow tube in the temperature range from 248 to 313 K, RH from 0.8% to 79%, and relative acidity (RA) of sulfuric acid from 6 × 10-5 to 0.38 (2 × 107-109 cm-3). The impurity levels of base compounds were determined to be NH3 nucleation at fixed sulfuric acid concentration but impede nucleation when RA is fixed. It is also shown that binary nucleation of sulfuric acid and water is negligible in planetary boundary layer temperature and sulfuric acid ranges. An empirical algorithm was derived to correlate the nucleation rate with RA, RH, and temperature together. Collision-limited condensation of free-sulfuric acid molecules fails to predict the observed growth rate in the sub-3 nm size range, as well as its dependence on temperature and RH. This suggests that evaporation, sulfuric acid hydration, and possible involvement of other ternary molecules should be considered for the sub-3 nm particle growth.
Characterization of volatile organic compound adsorption on multiwall carbon nanotubes under different levels of relative humidity using linear solvation energy relationship

Energy Technology Data Exchange (ETDEWEB)

Li, Mei-syue; Wu, Siang Chen; Shih, Yang-hsin, E-mail: yhs@ntu.edu.tw

2016-09-05

Highlights: • LSER equations successfully predicted VOC sorption on MCNT at different humidity. • The five parameters in LSER could be narrowed down to three ones. • Main interaction is dispersion and partly dipolarity as well as hydrogen-bonds. • With increasing RH, it changes to cavity formation and hydrogen-bond basicity. • This approach can facilitate the VOC control design and the fate prediction. - Abstract: Multiwall carbon nanotubes (MWCNTs) have been used as an adsorbent for evaluating the gas/solid partitioning of selected volatile organic compounds (VOCs). In this study, 15 VOCs were probed to determine their gas/solid partitioning coefficient (Log K{sub d}) using inverse gas chromatography at different relative humidity (RH) levels. Interactions between MWCNTs and VOCs were analyzed by regressing the observed Log K{sub d} with the linear solvation energy relationship (LSER). The results demonstrate that the MWCNT carbonyl and carboxyl groups provide high adsorption capacity for the VOCs (Log K{sub d} 3.72–5.24 g/kg/g/L) because of the π-/n-electron pair interactions and hydrogen-bond acidity. The increasing RH gradually decreased the Log K{sub d} and shifted the interactions to dipolarity/polarizability, hydrogen-bond basicity, and cavity formation. The derived LSER equations provided adequate fits of Log K{sub d}, which is useful for VOC-removal processes and fate prediction of VOC contaminants by MWCNT adsorption in the environment.

Preservation of H2sub> production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures: Preservation of R. palustris latex coatings

Energy Technology Data Exchange (ETDEWEB)

Piskorska, M. [Univ. of South Carolina, Aiken, SC (United States); Soule, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gosse, J. L. [North Carolina State Univ., Raleigh, NC (United States); Milliken, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Flickinger, M. C. [North Carolina State Univ., Raleigh, NC (United States); Smith, G. W. [Univ. of South Carolina, Aiken, SC (United States); Yeager, C. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2013-01-21

To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2sub> on preservation of H2sub> production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2sub> production activity, whereas considerable H2sub> production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H2sub> production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2sub> (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2sub> production activity after 8 weeks of storage. In conWhen stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2sub> production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.
Effects of sole and mixed culture of wheat crop and phosphorus fertilization on the solubility of phosphorus in the soil

International Nuclear Information System (INIS)

Mahmood, H. R.; Ali, M. A.; Ahmad, N.

2016-01-01

Farmers face a challenging task to harvest yield potential of crops as well as improving fertilizer use-efficiency under their limited farm resources. Among the macronutrients, the relative efficiency of phosphorus fertilizer is very low in alkaline-calcareous soils under arid and semi-arid environments. Therefore, a field study was undertaken to quantify the interactive effects of wheat varieties and phosphorous fertilization on grain yield and solubility of phosphorous nutrient in the rhizosphere. The treatments consisted of (a) two wheat varieties (Sehr-2006, Shafaq-2006, mixed culture) and (b) three phosphorus levels (0, 45, 85 kg P/sub 2/O/sub 5/ per hectare) were arranged in randomized complete block design and replicated four times. The Results showed that biological grain yield and 1000-grain weight of wheat increased by 8.7 percent, 14.46 percent and 8.48 percent under mixed culture of varieties sehr-2006 and shafaq-2006, respectively over the solely grown varieties. The application of phosphorus at the rate 85 kg P/sub 2/O/sub 5/ ha/sup -1/ resulted in increased quantity of total biological yield, grain yield and 1000-grain weight compared to unfertilized crop. The uptake of nitrogen and phosphorus contents were substantially enhanced under mixed culture cropping pattern over sole wheat cultivars. The availability of phosphorus was increased by 19.70 percent under mixed cropping over sole culture. It is inferred from the study that mixed cropping produced synergetic effects on the availability of nutrients in the rhizosphere, and thereby resulted in the higher production of wheat crop. (author)
Multi-channel fiber optic dew and humidity sensor

Science.gov (United States)

Limodehi, Hamid E.; Mozafari, Morteza; Amiri, Hesam; Légaré, François

2018-03-01

In this article, we introduce a multi-channel fiber optic dew and humidity sensor which works using a novel method based on relation between surface plasmon resonance (SPR) and water vapor condensation. The proposed sensor can instantly detect moisture or dew formation through its fiber optic channels, separately situated in different places. It enables to simultaneously measure the ambient Relative Humidity (RH) and dew point temperature of several environments with accuracy of 5%.
Growth orientation and superconducting properties of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} films prepared by the low-fluorine sol-gel process

Energy Technology Data Exchange (ETDEWEB)

Lei Li; Zhao Gaoyang; Xu Hui; Zhao Juanjuan, E-mail: leili813@gmail.co [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China)

2010-08-15

YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) films were deposited on (100)-oriented LaAlO{sub 3} (LAO) single crystal substrates by the dip-coating process using low-fluorine solution. Their microstructures were characterized with the aid of X-ray diffractometry, scanning electron microscopy and high-resolution transmission electron microscopy. Their superconducting properties were measured by the standard four-probe method. The experiment results show that the film obtained under high enough humidity conditions exhibits better c-axis texture and superconducting properties than the film under a relatively low humidity conditions. Based on the classical nucleation and chemical reaction thermodynamics theory, the underlying crystalline and growth mechanisms of YBCO films under certain humidity conditions are explained in combination with our experimental results. It is suggested that the unreacted intermediate phases such as BaF{sub 2} and CuO aggregated in the YBCO grain boundary will cause lattice distortion in the YBCO matrix and further induce the formation of a-axis oriented YBCO grains as crystallization proceeds. Therefore, it is believed that the relative content of water vapor within the heat-treatment atmosphere plays quite an important role in the preparation of c-axis oriented YBCO film with good superconducting properties. (semiconductor materials)
Effects of tropical ecosystem engineers on soil quality and crop performance under different tillage and residue management

Science.gov (United States)

Pulleman, Mirjam; Paul, Birthe; Fredrick, Ayuke; Hoogmoed, Marianne; Hurisso, Tunsisa; Ndabamenye, Telesphore; Saidou, Koala; Terano, Yusuke; Six, Johan; Vanlauwe, Bernard

2014-05-01

Feeding a future global population of 9 billion will require a 70-100% increase in food production, resulting in unprecedented challenges for agriculture and natural resources, especially in Sub-saharan Africa (SSA). Agricultural practices that contribute to sustainable intensification build on beneficial biological interactions and ecosystem services. Termites are the dominant soil ecosystem engineers in arid to sub-humid tropical agro-ecosystems. Various studies have demonstrated the potential benefits of termites for rehabilitation of degraded and crusted soils and plant growth in semi-arid and arid natural ecosystems. However, the contribution of termites to agricultural productivity has hardly been experimentally investigated, and their role in Conservation Agriculture (CA) systems remains especially unclear. Therefore, this study aimed to quantify the effects of termites and ants on soil physical quality and crop productivity under different tillage and residue management systems in the medium term. A randomized block trial was set up in sub-humid Western Kenya in 2003. Treatments included a factorial combination of residue retention and removal (+R/-R) and conventional and reduced tillage (+T/-T) under a maize (Zea mays L.) and soybean (Glyxine max. L.) rotation. A macrofauna exclusion experiment was superimposed in 2005 as a split-plot factor (exclusion +ins; inclusion -ins) by regular applications of pesticides (Dursban and Endosulfan) in half of the plots. Macrofauna abundance and diversity, soil aggregate fractions, soil carbon contents and crop yields were measured between 2005 and 2012 at 0-15 cm and 15-30 cm soil depths. Termites were the most important macrofauna species, constituting between 48-63% of all soil biota, while ants were 13-34%, whereas earthworms were present in very low numbers. Insecticide application was effective in reducing termites (85-56% exclusion efficacy) and earthworms (87%), and less so ants (49-81%) at 0-15 cm soil depth
Experimental investigations of a chimney-dependent solar crop dryer

Energy Technology Data Exchange (ETDEWEB)

Afriyie, J.K.; Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester LE1 9BH (United Kingdom); Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

2009-01-15

An experimental investigation into the performance of a solar crop dryer with solar chimney and no air preheating is described. Tests were first performed on the cabinet dryer, using a normal chimney. The trials were repeated with a solar chimney. Still with the solar chimney, further trials were carried out with the roof of the drying chamber inclined further to form a tent dryer. The described tests include no-load tests for airflow rate measurements and drying tests, with cassava as the crop. Air velocities, temperatures, ambient relative humidity and the drop in crop moisture contents at different stages of the drying process are also presented. The effects of the various configurations described above on the drying process are deduced and discussed while comparing the experimental results with one another. In addition, the performance of the dryer in relation to other natural convection dryers is discussed. The results show that the solar chimney can increase the airflow rate of a direct-mode dryer especially when it is well designed with the appropriate angle of drying-chamber roof. However, the increase in flow rate only increases the drying rate when the relative humidity (RH) of the ambient air is below a certain mark (60% for cassava). (author)
Cover crops support ecological intensification of arable cropping systems

Science.gov (United States)

Wittwer, Raphaël A.; Dorn, Brigitte; Jossi, Werner; van der Heijden, Marcel G. A.

2017-02-01

A major challenge for agriculture is to enhance productivity with minimum impact on the environment. Several studies indicate that cover crops could replace anthropogenic inputs and enhance crop productivity. However, so far, it is unclear if cover crop effects vary between different cropping systems, and direct comparisons among major arable production systems are rare. Here we compared the short-term effects of various cover crops on crop yield, nitrogen uptake, and weed infestation in four arable production systems (conventional cropping with intensive tillage and no-tillage; organic cropping with intensive tillage and reduced tillage). We hypothesized that cover cropping effects increase with decreasing management intensity. Our study demonstrated that cover crop effects on crop yield were highest in the organic system with reduced tillage (+24%), intermediate in the organic system with tillage (+13%) and in the conventional system with no tillage (+8%) and lowest in the conventional system with tillage (+2%). Our results indicate that cover crops are essential to maintaining a certain yield level when soil tillage intensity is reduced (e.g. under conservation agriculture), or when production is converted to organic agriculture. Thus, the inclusion of cover crops provides additional opportunities to increase the yield of lower intensity production systems and contribute to ecological intensification.
Ingestion of a cold temperature/menthol beverage increases outdoor exercise performance in a hot, humid environment.

Science.gov (United States)

Tran Trong, Than; Riera, Florence; Rinaldi, Kévin; Briki, Walid; Hue, Olivier

2015-01-01

A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions. Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol) beverage at three temperatures: Neutral (ambient temperature) (28.7°C±0. 5°C), Cold (3.1°C±0.6°C) or Ice-slurry (0.17°C±0.07°C). Trial time, core temperature (Tco), heart rate (HR), rate of perceived exertion (RPE), thermal sensation (TS) and thermal comfort (TC) were assessed. Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol. A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone). Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE) between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.
Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

OpenAIRE

Majewski Jacek

2017-01-01

Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based ...
Particles and emissions from a diesel engine equipped with a humid air motor system

Energy Technology Data Exchange (ETDEWEB)

Nord, Kent; Zurita, Grover; Tingvall, Bror; Haupt, Dan [Luleaa Univ. of Technology (Sweden). Div. of Environmental Technology

2002-02-01

A system for reduction of NO{sub x}, humid air motor system (HAM), has been connected to an eleven liters diesel engine. Earlier studies have demonstrated the system's capacity to lower NO{sub x}-emissions from diesel engines. The present study is directed to investigate their influence of the system on the emissions of particles, aldehydes and noise while at the same time monitoring essential engine parameters, water consumption and verifying the NO{sub x} reducing ability. The system has been tested under the various conditions stated in 13-mode cycle ECE R-49. Additional tests have been necessary for sampling and measurements of particles and noise. The results show that HAM caused a large reduction of the NO{sub x} emissions while the engine performance was almost unaffected. Average reduction of NO{sub x} during the different modes of ECE R-49 was 51,1%. The reduction was directly related to the humidity of the inlet air and a further reduction can be anticipated with higher humidity. Samples have also been taken for acetaldehydes and formaldehyde. The results suggest a large reduction of aldehydes, in the range of 78 to 100%, when using HAM. Unfortunately it cannot be excluded that the results obtained are a result of a combination of high air humidity and the sampling technique used. The influence of the system on the emission of hydrocarbons was negligible while a moderate increase in the emission of carbon monoxide was noticed. No confident relationship between air humidity and the observed effects could be detected. Particle number concentrations and size distribution have also been measured. The measurements showed that the particle number concentrations was usually increased when HAM was coupled to the engine. The increase in particle number concentration, observed in five out of six running modes, varied between 46 and 148%. There was no trend indicating a shift in mean particle diameter when using HAM. Noise level and cylinder pressure have also
Biofuels development in Sub-Saharan Africa: Are the policies conducive?

International Nuclear Information System (INIS)

Jumbe, Charles B.L.; Msiska, Frederick B.M.; Madjera, Michael

2009-01-01

This paper analyses national, regional and international biofuels policies and strategies to assess whether these policies promote or undermine the development of biofuels sector in Africa. Despite having a huge comparative advantage in land, labour and good climatic conditions favourable for the growing of energy crops, few countries in Sub-Saharan Africa have included biofuels strategies in their energy or national development policies. Further results show that while developed countries commit huge financial resources for research, technology development and the provision of tax-incentives to both producers and consumers, there is little government support for promoting biofuels in Africa. Although the consequences of biofuels on food supply remain uncertain, the mandatory blending of biofuels with fossil fuels by industrialized countries will create demand for land in Africa for the growing of energy crops for biofuels. This paper urgently calls upon national governments in Sub-Saharan Africa to develop appropriate strategies and regulatory frameworks to harness the potential economic opportunities from biofuels sector development, while protecting the environment and rural communities from the adverse effects of land alienation from the mainstream agriculture towards the growing of energy crops for biofuels at the expense of traditional food crops.
Biofuels development in Sub-Saharan Africa: Are the policies conducive?

Energy Technology Data Exchange (ETDEWEB)

Jumbe, Charles B.L., E-mail: charlesjumbe@bunda.unima.m [University of Malawi, Centre for Agricultural Research and Development, Bunda College, P.O. Box 219, Lilongwe (Malawi); Msiska, Frederick B.M., E-mail: frederickmsiska@yahoo.co [Ministry of Agriculture and Food Security, P.O. Box 30134, Lilongwe 3 (Malawi); Madjera, Michael, E-mail: michael.madjera@onlinehome.d [Evangelical Church in Middle Germany, P.O. Box 1424, 39004 Magdeburg (Germany)

2009-11-15

This paper analyses national, regional and international biofuels policies and strategies to assess whether these policies promote or undermine the development of biofuels sector in Africa. Despite having a huge comparative advantage in land, labour and good climatic conditions favourable for the growing of energy crops, few countries in Sub-Saharan Africa have included biofuels strategies in their energy or national development policies. Further results show that while developed countries commit huge financial resources for research, technology development and the provision of tax-incentives to both producers and consumers, there is little government support for promoting biofuels in Africa. Although the consequences of biofuels on food supply remain uncertain, the mandatory blending of biofuels with fossil fuels by industrialized countries will create demand for land in Africa for the growing of energy crops for biofuels. This paper urgently calls upon national governments in Sub-Saharan Africa to develop appropriate strategies and regulatory frameworks to harness the potential economic opportunities from biofuels sector development, while protecting the environment and rural communities from the adverse effects of land alienation from the mainstream agriculture towards the growing of energy crops for biofuels at the expense of traditional food crops.
Biofuels development in Sub-Saharan Africa. Are the policies conducive?

Energy Technology Data Exchange (ETDEWEB)

Jumbe, Charles B.L. [University of Malawi, Centre for Agricultural Research and Development, Bunda College, P.O. Box 219, Lilongwe (Malawi); Msiska, Frederick B.M. [Ministry of Agriculture and Food Security, P.O. Box 30134, Lilongwe 3 (Malawi); Madjera, Michael [Evangelical Church in Middle Germany, P.O. Box 1424, 39004 Magdeburg (Germany)

2009-11-15

This paper analyses national, regional and international biofuels policies and strategies to assess whether these policies promote or undermine the development of biofuels sector in Africa. Despite having a huge comparative advantage in land, labour and good climatic conditions favourable for the growing of energy crops, few countries in Sub-Saharan Africa have included biofuels strategies in their energy or national development policies. Further results show that while developed countries commit huge financial resources for research, technology development and the provision of tax-incentives to both producers and consumers, there is little government support for promoting biofuels in Africa. Although the consequences of biofuels on food supply remain uncertain, the mandatory blending of biofuels with fossil fuels by industrialized countries will create demand for land in Africa for the growing of energy crops for biofuels. This paper urgently calls upon national governments in Sub-Saharan Africa to develop appropriate strategies and regulatory frameworks to harness the potential economic opportunities from biofuels sector development, while protecting the environment and rural communities from the adverse effects of land alienation from the mainstream agriculture towards the growing of energy crops for biofuels at the expense of traditional food crops. (author)
Anisotropic Proton and Oxygen Ion Conductivity in Epitaxial Ba2sub>In>2sub>O>5sub> Thin Films

DEFF Research Database (Denmark)

Fluri, Aline; Gilardi, Elisa; Karlsson, Maths

2017-01-01

Solid oxide oxygen ion and proton conductors are a highly important class of materials for renewable energy conversion devices like solid oxide fuel cells. Ba2In2O5 (BIO) exhibits both oxygen ion and proton conduction, in a dry and humid environment, respectively. In a dry environment...
Bacillus thuringiensis (Bt) transgenic crop: an environment friendly insect-pest management strategy.

Science.gov (United States)

Kumar, Suresh; Chandra, Amaresh; Pandey, K C

2008-09-01

of biosafety protocol is necessary to protect human health and environment from the possible adverse effects of the products of genetic engineering. The debate between proponents and opponents of GM technology has created major obstacles in hamessing benefits of the technology It has now become clear that transgenics willbe accepted by the public only when doubts related with general risks and environmental safety are adequately dispelled. Thus, there is need to organize public awareness and present the benefits of Bt transgenic crops to improve social attitude for their rational deployment. In this review, an attempt has been made to discuss social and environmental safety issues of Bt transgenic crops.
Selection on crop-derived traits and QTL in sunflower (Helianthus annuus) crop-wild hybrids under water stress.

Science.gov (United States)

Owart, Birkin R; Corbi, Jonathan; Burke, John M; Dechaine, Jennifer M

2014-01-01

Locally relevant conditions, such as water stress in irrigated agricultural regions, should be considered when assessing the risk of crop allele introgression into wild populations following hybridization. Although research in cultivars has suggested that domestication traits may reduce fecundity under water stress as compared to wild-like phenotypes, this has not been investigated in crop-wild hybrids. In this study, we examine phenotypic selection acting on, as well as the genetic architecture of vegetative, reproductive, and physiological characteristics in an experimental population of sunflower crop-wild hybrids grown under wild-like low water conditions. Crop-derived petiole length and head diameter were favored in low and control water environments. The direction of selection differed between environments for leaf size and leaf pressure potential. Interestingly, the additive effect of the crop-derived allele was in the direction favored by selection for approximately half the QTL detected in the low water environment. Selection favoring crop-derived traits and alleles in the low water environment suggests that a subset of these alleles would be likely to spread into wild populations under water stress. Furthermore, differences in selection between environments support the view that risk assessments should be conducted under multiple locally relevant conditions.
Exceptional enhancement of H{sub 2} production in alkaline environment over plasmonic Au/TiO{sub 2} photocatalyst under visible light

Energy Technology Data Exchange (ETDEWEB)

Meng, Xianguang; Liu, Guigao [Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814 (Japan); Environmental Remediation Materials Unit and International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Yu, Qing [Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814 (Japan); Wang, Tao; Chang, Kun; Li, Peng [Environmental Remediation Materials Unit and International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Liu, Lequan, E-mail: Jinhua.YE@nims.go.jp, E-mail: Lequan.Liu@tju.edu.cn [TU-NIMS Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Tianjin 300072 (China); Ye, Jinhua, E-mail: Jinhua.YE@nims.go.jp, E-mail: Lequan.Liu@tju.edu.cn [Graduate School of Chemical Science and Engineering, Hokkaido University, Sapporo 060-0814 (Japan); Environmental Remediation Materials Unit and International Center for Materials Nanoarchitectonics (WPI-MANA), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); TU-NIMS Joint Research Center, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Tianjin 300072 (China)

2015-10-01

A reaction environment modulation strategy was employed to promote the H{sub 2} production over plasmonic Au/semiconductor composites. It is shown that the fast consumption of the holes in plasmonic Au nanoparticles by methanol in alkaline reaction environment remarkably increases H{sub 2} generation rate under visible light. The photocatalytic reaction is mainly driven by the interband transition of plasmonic Au nanoparticles, and the apparent quantum efficiency of plasmon-assisted H{sub 2} production at pH 14 reaches 6% at 420 nm. The reaction environment control provides a simple and effective way for the highly efficient solar fuel production from biomass reforming through plasmonic photocatalysis in future.
Testing and ground calibration of DREAMS-H relative humidity device

Science.gov (United States)

Genzer, Maria; Hieta, Maria; Nikkanen, Timo; Schmidt, Walter; Kemppinen, Osku; Harri, Ari-Matti; Haukka, Harri

2015-04-01

DREAMS (Dust Characterization, Risk Assessment and Environmental Analyzer on the Martian Surface) instrument suite is to be launched as part of the ESA ExoMars 2016/Schiaparelli lander. DREAMS consists of an environmental package for monitoring temperature, pressure, relative humidity, winds and dust opacity, as well as atmospheric electricity of Martian atmosphere. The DREAMS instruments and scientific goals are described in [1]. Here we describe testing and ground calibration of the relative humidity device, DREAMS-H, provided to the DREAMS payload by the Finnish Meteorological Institute and based on proprietary technology of Vaisala, Inc. The same kind of device is part of the REMS instrument package onboard MSL Curiosity Rover [2][3]. DREAMS-H is based on Vaisala Humicap® technology adapted for use in Martian environment by the Finnish Meteorological Institute. The device is very small and lightweighed, with total mass less than 20 g and consuming only 15 mW of power. The Humicap® sensor heads contain an active polymer film that changes its capacitance as function of relative humidity, with 0% to 100% RH measurement range. The dynamic range of the device gets smaller with sensor temperature, being in -70°C approximately 30% of the dynamic range in 0°C [3]. Good-quality relative humidity measurements require knowing the temperature of the environment in which relative humidity is measured. An important part of DREAMS-H calibration was temperature calibration of Vaisala Thermocap® temperature sensors used for housekeeping temperature measurements of the DREAMS-H device. For this, several temperature points in the desired operational range were measured with 0.1°C accuracy traceable to national standards. The main part of humidity calibration of DREAMS-H flight models was done in subzero temperatures in a humidity generator of the Finnish Center of Metrology and Accreditation (MIKES). Several relative humidity points ranging from almost dry to almost wet
Low-cost personal cooling in hot humid offices

DEFF Research Database (Denmark)

Gunnarsen, Lars Bo; Santos, A.

This report presents a low cost solution to avoid heat stress in a hot and humid environment based on a solar powered drying of supply air. The air drying facilities and a validation of the benefits through comprehensive human exposure studies are described. The study represents an example...... of applied participative research performed in a developing country. The report may be used as a background for the improvement of the indoor climate in poor, hot and humid regions without increased use of electricity....
Effect of humidity on the filter pressure drop

Energy Technology Data Exchange (ETDEWEB)

Vendel, J.; Letourneau, P. [Institut de Protection et de Surete Nucleaire, Gif-sur-Yvette (France)

1995-02-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO{sub 2}). Cesium hydroxyde (CsOH) of size of 2 {mu} M AMMD has been generated by an ultrasonic generator and the 0.7 {mu}m AMMD titanium oxyde has been dispersed by a {open_quotes}turn-table{close_quotes} generator. As it is noted in the BISWAS`publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced.

Passive wireless surface acoustic wave sensors for monitoring sequestration sites CO2sub> emission

Energy Technology Data Exchange (ETDEWEB)

Wang, Yizhong [Univ. of Pittsburgh, PA (United States); Chyu, Minking [Univ. of Pittsburgh, PA (United States); Wang, Qing-Ming [Univ. of Pittsburgh, PA (United States)

2013-02-14

University of Pittsburgh’s Transducer lab has teamed with the U.S. Department of Energy’s National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient CO2sub> measuring technologies for geological sequestration sites leakage monitoring. A passive wireless CO2sub> sensing system based on surface acoustic wave technology and carbon nanotube nanocomposite was developed. Surface acoustic wave device was studied to determine the optimum parameters. Delay line structure was adopted as basic sensor structure. CNT polymer nanocomposite was fabricated and tested under different temperature and strain condition for natural environment impact evaluation. Nanocomposite resistance increased for 5 times under pure strain, while the temperature dependence of resistance for CNT solely was -1375ppm/°C. The overall effect of temperature on nanocomposite resistance was -1000ppm/°C. The gas response of the nanocomposite was about 10% resistance increase under pure CO2sub> . The sensor frequency change was around 300ppm for pure CO2sub> . With paralyne packaging, the sensor frequency change from relative humidity of 0% to 100% at room temperature decreased from over 1000ppm to less than 100ppm. The lowest detection limit of the sensor is 1% gas concentration, with 36ppm frequency change. Wireless module was tested and showed over one foot transmission distance at preferred parallel orientation.
Absolute humidity and the human nose: A reanalysis of climate zones and their influence on nasal form and function.

Science.gov (United States)

Maddux, Scott D; Yokley, Todd R; Svoma, Bohumil M; Franciscus, Robert G

2016-10-01

Investigations into the selective role of climate on human nasal variation commonly divide climates into four broad adaptive zones (hot-dry, hot-wet, cold-dry, and cold-wet) based on temperature and relative humidity. Yet, absolute humidity-not relative humidity-is physiologically more important during respiration. Here, we investigate the global distribution of absolute humidity to better clarify ecogeographic demands on nasal physiology. We use monthly observations from the Climatic Research Unit Timeseries 3 (CRU TS3) database to construct global maps of average annual temperature, relative humidity and absolute humidity. Further, using data collected by Thomson and Buxton (1923) for over 15,000 globally-distributed individuals, we calculate the actual amount of heat and water that must be transferred to inspired air in different climatic regimes to maintain homeostasis, and investigate the influence of these factors on the nasal index. Our results show that absolute humidity, like temperature, generally decreases with latitude. Furthermore, our results demonstrate that environments typically characterized as "cold-wet" actually exhibit low absolute humidities, with values virtually identical to cold-dry environments and significantly lower than hot-wet and even hot-dry environments. Our results also indicate that strong associations between the nasal index and absolute humidity are, potentially erroneously, predicated on individuals from hot-dry environments possessing intermediate (mesorrhine) nasal indices. We suggest that differentially allocating populations to cold-dry or cold-wet climates is unlikely to reflect different selective pressures on respiratory physiology and nasal morphology-it is cold-dry, and to a lesser degree hot-dry environments, that stress respiratory function. Our study also supports assertions that demands for inspiratory modification are reduced in hot-wet environments, and that expiratory heat elimination for thermoregulation is a
A statistical analysis of three ensembles of crop model responses totemperature and CO2sub>concentration

DEFF Research Database (Denmark)

Makowski, D; Asseng, S; Ewert, F.

2015-01-01

Ensembles of process-based crop models are increasingly used to simulate crop growth for scenarios of temperature and/or precipitation changes corresponding to different projections of atmospheric CO2 concentrations. This approach generates large datasets with thousands of simulated crop yield data...
Effect of humidity and temperature on the survival of Listeria monocytogenes on surfaces.

Science.gov (United States)

Redfern, J; Verran, J

2017-04-01

Listeria monocytogenes is a pathogenic bacterium, with human disease and infection linked to dairy products, seafood, ready-to-eat meat and raw & undercooked meats. Stainless steel is the most common food preparation surface and therefore, it is important to understand how food storage conditions such as surface materials, temperature and relative humidity can affect survival of L. monocytogenes. In this study, survival of L. monocytogenes on stainless steel was investigated at three temperatures (4, 10 and 21°C), each approx. 11, 50 and 85% humidity. Results indicate that the lower the temperature, the more cells were recovered in all three humidity environments, while medium humidity enhances survival, irrespective of temperature. Lower humidity decreases recovery at all temperatures. These data support the guidance noted above that humidity control is important, and that lower humidity environments are less likely to support retention of viable L. monocytogenes on a stainless steel surface. Understanding survival of potential food-borne pathogens is essential for the safe production and preparation of food. While it has long been 'common knowledge' that relative humidity can affect the growth and survival of micro-organisms, this study systematically describes the survival of L. monocytogenes on stainless steel under varying humidity and temperatures for the first time. The outcomes from this paper will allow those involved with food manufacture and preparation to make informed judgement on environmental conditions relating to humidity control, which is lacking in the food standards guidelines. © 2017 The Society for Applied Microbiology.
Assessing Reservoir Depositional Environments to Develop and Quantify Improvements in CO2sub> Storage Efficiency. A Reservoir Simulation Approach

Energy Technology Data Exchange (ETDEWEB)

Okwen, Roland [University of Illinois, Champaign, IL (United States); Frailey, Scott [University of Illinois, Champaign, IL (United States); Leetaru, Hannes [University of Illinois, Champaign, IL (United States); Moulton, Sandy [Illinois State Geological Survey, Champaign, IL (United States)

2014-09-30

The storage potential and fluid movement within formations are dependent on the unique hydraulic characteristics of their respective depositional environments. Storage efficiency (E) quantifies the potential for storage in a geologic depositional environment and is used to assess basinal or regional CO2sub> storage resources. Current estimates of storage resources are calculated using common E ranges by lithology and not by depositional environment. The objectives of this project are to quantify E ranges and identify E enhancement strategies for different depositional environments via reservoir simulation studies. The depositional environments considered include deltaic, shelf clastic, shelf carbonate, fluvial deltaic, strandplain, reef, fluvial and alluvial, and turbidite. Strategies considered for enhancing E include CO2sub> injection via vertical, horizontal, and deviated wells, selective completions, water production, and multi-well injection. Conceptual geologic and geocellular models of the depositional environments were developed based on data from Illinois Basin oil fields and gas storage sites. The geologic and geocellular models were generalized for use in other US sedimentary basins. An important aspect of this work is the development of conceptual geologic and geocellular models that reflect the uniqueness of each depositional environment. Different injection well completions methods were simulated to investigate methods of enhancing E in the presence of geologic heterogeneity specific to a depositional environment. Modeling scenarios included horizontal wells (length, orientation, and inclination), selective and dynamic completions, water production, and multiwell injection. A Geologic Storage Efficiency Calculator (GSECalc) was developed to calculate E from reservoir simulation output. Estimated E values were normalized to diminish their dependency on fluid relative permeability. Classifying depositional environments according to
Heterogeneous global crop yield response to biochar: a meta-regression analysis

International Nuclear Information System (INIS)

Crane-Droesch, Andrew; Torn, Margaret S; Abiven, Samuel; Jeffery, Simon

2013-01-01

Biochar may contribute to climate change mitigation at negative cost by sequestering photosynthetically fixed carbon in soil while increasing crop yields. The magnitude of biochar’s potential in this regard will depend on crop yield benefits, which have not been well-characterized across different soils and biochars. Using data from 84 studies, we employ meta-analytical, missing data, and semiparametric statistical methods to explain heterogeneity in crop yield responses across different soils, biochars, and agricultural management factors, and then estimate potential changes in yield across different soil environments globally. We find that soil cation exchange capacity and organic carbon were strong predictors of yield response, with low cation exchange and low carbon associated with positive response. We also find that yield response increases over time since initial application, compared to non-biochar controls. High reported soil clay content and low soil pH were weaker predictors of higher yield response. No biochar parameters in our dataset—biochar pH, percentage carbon content, or temperature of pyrolysis—were significant predictors of yield impacts. Projecting our fitted model onto a global soil database, we find the largest potential increases in areas with highly weathered soils, such as those characterizing much of the humid tropics. Richer soils characterizing much of the world’s important agricultural areas appear to be less likely to benefit from biochar. (letter)
Integrated water-crop-soil-management system for evaluating the quality of irrigation water

International Nuclear Information System (INIS)

Pla-Sentis, I.

1983-01-01

The authors make use of an independent balance of the salts and ions present in the water available for irrigation, based on the residence times in the soil solution that are allowed by solubility limits and drainage conditions, to develop an efficient system for evaluating the quality of such water which combines the factors: water, crop, soil and management. The system is based on the principle that such quality depends not only on the concentration and composition of the salts dissolved in the water, but also on existing possibilities and limitations in using and managing it in respect of the soil and crops, with allowance for the crop's tolerance of salinity, drainage conditions and hydrological properties of the soils, climate and current or potential practices for the management of the irrigation. If this system is used to quantify approximately the time behaviour of the concentration and composition of the salts in the soil solution, it is possible not only to predict the effects on soil, crops and drainage water, but also to evaluate the various combinations of irrigation water, soil, crops and management and to select the most suitable. It is also useful for fairly accurately diagnosing current problems of salinity and for identifying alternatives and possibilities for reclamation. Examples of its use for these purposes in Venezuela are presented with particular reference to the diagnosis of the present and future development of ''salino-sodic'' and ''sodic'' soils by means of low-salt irrigation water spread over agricultural soils with very poor drainage in a sub-humid or semi-arid tropical climate. The authors also describe the use of radiation techniques for gaining an understanding of the relations between the factors making up the system and for improving the quantitative evaluations required to diagnose problems and to select the best management methods for the available irrigation water. (author)
Carbon isotope discrimination as a selection tool for high water use efficiency and high crop yields

Energy Technology Data Exchange (ETDEWEB)

Kumarasinghe, K S; Kirda, C; Bowen, G D [Joint FAO/IAEA Div. of Nuclear Techniques in Food and Agriculture, Vienna (Austria). Soil Fertility, Irrigation and Crop Production Section; Zapata, F; Awonaike, K O; Holmgren, E; Arslan, A; De Bisbal, E C; Mohamed, A R.A.G.; Montenegro, A [FAO/IAEA Agriculture and Biotechnology Lab., Seibersdorf (Austria). Soils Science Unit

1996-07-01

Results of back-up research conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in support of the FAO/IAEA Co-ordinated Research Programme on the Use of Isotope Studies on Increasing and Stabilizing Plant Productivity in Low Phosphate and Semi-arid and Sub-humid Soils of the Tropics and Sub-tropics, are presented here. Neutron probe measurements confirmed the earlier reports of a strong correlation of {Delta} with grain yield and water use efficiency of wheat. High soil gypsum content and soil salinity, a wide spread problem in soils of arid and semi-arid climatic zones, do not interfere with the association of {Delta} with crop yields, provided plants are grown in similar soil water status and soil fertility level. Results of a glasshouse experiment using selected cowpea genotypes showed that {Delta} values measured at flowering stage positively correlated with total dry matter production and percent N{sub 2} derived from atmosphere (%Ndfa), contributing to an earlier report from the laboratory that it may be possible to use {Delta} values for screening of leguminous crops for high N{sub 2} fixation potential. {sup 13}C isotope discrimination in the leaves of Gliricidia sepium was measured to examine if the technique could be extended to studies with trees. Results of a glasshouse experiment with 18 provenances of Gliricidia sepium showed highly significant correlations of {Delta} with total dry matter production, water use efficiency and total N accumulated through biological nitrogen fixation. Although the correlation of {Delta} with water use efficiency and dry matter yield are relatively clear and better understood, the correlation with nitrogen fixation still needs a closer examination under different environmental conditions and with different species. (Abstract Truncated)
Ingestion of a cold temperature/menthol beverage increases outdoor exercise performance in a hot, humid environment.

Directory of Open Access Journals (Sweden)

Than Tran Trong

Full Text Available A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions.Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol beverage at three temperatures: Neutral (ambient temperature (28.7°C±0. 5°C, Cold (3.1°C±0.6°C or Ice-slurry (0.17°C±0.07°C. Trial time, core temperature (Tco, heart rate (HR, rate of perceived exertion (RPE, thermal sensation (TS and thermal comfort (TC were assessed.Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol.A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone. Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.
Roots Withstanding their Environment: Exploiting Root System Architecture Responses to Abiotic Stress to Improve Crop Tolerance

Science.gov (United States)

Koevoets, Iko T.; Venema, Jan Henk; Elzenga, J. Theo. M.; Testerink, Christa

2016-01-01

To face future challenges in crop production dictated by global climate changes, breeders and plant researchers collaborate to develop productive crops that are able to withstand a wide range of biotic and abiotic stresses. However, crop selection is often focused on shoot performance alone, as observation of root properties is more complex and asks for artificial and extensive phenotyping platforms. In addition, most root research focuses on development, while a direct link to the functionality of plasticity in root development for tolerance is often lacking. In this paper we review the currently known root system architecture (RSA) responses in Arabidopsis and a number of crop species to a range of abiotic stresses, including nutrient limitation, drought, salinity, flooding, and extreme temperatures. For each of these stresses, the key molecular and cellular mechanisms underlying the RSA response are highlighted. To explore the relevance for crop selection, we especially review and discuss studies linking root architectural responses to stress tolerance. This will provide a first step toward understanding the relevance of adaptive root development for a plant’s response to its environment. We suggest that functional evidence on the role of root plasticity will support breeders in their efforts to include root properties in their current selection pipeline for abiotic stress tolerance, aimed to improve the robustness of crops. PMID:27630659
Long-term exposure of /sup 238/PuO/sub 2/ to a terrestrial environment. Volume III

Energy Technology Data Exchange (ETDEWEB)

Heaton, R.C.; Patterson, J.H.; Steinkruger, F.J.; Coffelt, K.P.

1985-02-01

A plutonium oxide source consisting of a single piece of 83% /sup 238/PuO/sub 2/ and weighing 38 g was exposed for 2.9 years to a humid, temperate terrestrial environment in an environmental simulation chamber. The soil tray of the chamber was divided into four compartments so that different soil types could be studied under identical conditions. Soils examined in this experiment included loam, silt loam, sand, and humus. Plutonium released into the soils, the soil drainages, and the condensates from the dehumidifier was monitored throughout the experiment. The total plutonium release rate from the PuO/sub 2/ source was approximately 2 ng/m/sup 2//s. The generation of short-ranged airborne plutonium, able to travel from a few centimeters to half a meter, was one of the most significant release pathways. The amount of plutonium released in this way was 10 times that washed directly off the source by rainwater and 20 times that from the fully airborne (longer ranged) release. Of the 200 ..mu..g of plutonium deposited in the soils, less than 0.1 ..mu..g was released into the soil percolates. In fact, the soil percolates constituted the least significant release pathway. Within the uncertainties in deriving the plutonium inventories of the soil compartments, we found no discernible differences among the behaviors of the four soil types towards plutonium. There was little or no seasonal effect on the release of plutonium from the soil.
Enhancement of stack ventilation in hot and humid climate using a combination of roof solar collector and vertical stack

Energy Technology Data Exchange (ETDEWEB)

Yusoff, Wardah Fatimah Mohammad; Salleh, Elias [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Adam, Nor Mariah [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapian, Abdul Razak [Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Yusof Sulaiman, Mohamad [Solar Energy Research Institute, 3rd Floor, Tun Sri Lanang Library Building, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2010-10-15

In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (T{sub i}-T{sub o}) is achieved in the semi-clear sky condition, which is about 9.9 C (45.8 C-35.9 C). Meanwhile, in the overcast sky condition, the highest air temperature difference (T{sub i}-T{sub o}) is 6.2 C (39.3 C-33.1 C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector's channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. (author)
Evaporation and the sub-canopy energy environment in a flooded forest

Science.gov (United States)

The combination of canopy cover and a free water surface makes the sub-canopy environment of flooded forested wetlands unlike other aquatic or terrestrial systems. The sub-canopy vapor flux and energy budget are not well understood in wetlands, but they importantly control water level and understory...
Greenhouse gases emission from soils under major crops in Northwest India

Energy Technology Data Exchange (ETDEWEB)

Jain, N., E-mail: nivetajain@gmail.com [Centre for Environment Science and Climate Resilient Agriculture, ICAR-Indian Agricultural Research Institute, New Delhi 110 012 (India); Arora, P.; Tomer, R.; Mishra, Shashi Vind; Bhatia, A.; Pathak, H. [Centre for Environment Science and Climate Resilient Agriculture, ICAR-Indian Agricultural Research Institute, New Delhi 110 012 (India); Chakraborty, D. [Division of Agricultural Physics, ICAR-Indian Agricultural Research Institute, New Delhi 110 012 (India); Kumar, Vinod; Dubey, D.S.; Harit, R.C.; Singh, J.P. [Centre for Environment Science and Climate Resilient Agriculture, ICAR-Indian Agricultural Research Institute, New Delhi 110 012 (India)

2016-01-15

Quantification of greenhouse gases (GHGs) emissions from agriculture is necessary to prepare the national inventories and to develop the mitigation strategies. Field experiments were conducted during 2008–2010 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India to quantify nitrous oxide (N{sub 2}O), methane (CH{sub 4}), and carbon dioxide (CO{sub 2}) emissions from soils under cereals, pulses, millets, and oilseed crops. Total cumulative N{sub 2}O emissions were significantly different (P > 0.05) among the crop types. Emission of N{sub 2}O as percentage of applied N was the highest in pulses (0.67%) followed by oilseeds (0.55%), millets (0.43%) and cereals (0.40%). The emission increased with increasing rate of N application (r{sup 2} = 0.74, P < 0.05). The cumulative flux of CH{sub 4} from the rice crop was 28.64 ± 4.40 kg ha{sup −1}, while the mean seasonal integrated flux of CO{sub 2} from soils ranged from 3058 ± 236 to 3616 ± 157 kg CO{sub 2} ha{sup −1} under different crops. The global warming potential (GWP) of crops varied between 3053 kg CO{sub 2} eq. ha{sup −1} (pigeon pea) and 3968 kg CO{sub 2} eq. ha{sup −1} (wheat). The carbon equivalent emission (CEE) was least in pigeon pea (833 kg C ha{sup −1}) and largest in wheat (1042 kg C ha{sup −1}). The GWP per unit of economic yield was the highest in pulses and the lowest in cereal crops. The uncertainties in emission values varied from 4.6 to 22.0%. These emission values will be useful in updating the GHGs emission inventory of Indian agriculture. - Highlights: • Nitrous oxide, methane and carbon dioxide emission were quantified from soils under cereals, millets, oilseeds, and pulses in northwest India. • The emission of nitrous oxide ranged from 0.57–1.3 kg ha{sup −1}, methane from 27.78–29.50 kg ha{sup −1} and carbon dioxide from 2377–3910 kg ha{sup −1}. • Emission of nitrous oxide as percent of applied N was highest in pulses (0
Field Phenotyping and Long-Term Platforms to Characterise How Crop Genotypes Interact with Soil Processes and the Environment

Directory of Open Access Journals (Sweden)

Timothy S. George

2014-05-01

Full Text Available Unsustainable agronomic practices and environmental change necessitate a revolution in agricultural production to ensure food security. A new generation of crops that yield more with fewer inputs and are adapted to more variable environments is needed. However, major changes in breeding programmes may be required to achieve this goal. By using the genetic variation in crop yield in specific target environments that vary in soil type, soil management, nutrient inputs and environmental stresses, robust traits suited to specific conditions can be identified. It is here that long-term experimental platforms and field phenotyping have an important role to play. In this review, we will provide information about some of the field-based platforms available and the cutting edge phenotyping systems at our disposal. We will also identify gaps in our field phenotyping resources that should be filled. We will go on to review the challenges in producing crop ideotypes for the dominant management systems for which we need sustainable solutions, and we discuss the potential impact of three-way interactions between genetics, environment and management. Finally, we will discuss the role that modelling can play in allowing us to fast-track some of these processes to allow us to make rapid gains in agricultural sustainability.
Methods to enhance hydrolysis during one and two-stage anaerobic digestion of energy crops and crop residues

Energy Technology Data Exchange (ETDEWEB)

Jagadabhi, P. S.

2011-07-01

The objective of this thesis was to evaluate methods to enhance hydrolysis (measured as specific SCOD production, g SCOD g-1 VS) during one and two-stage anaerobic digestion (AD) of energy crops and crop residues. Addition of macro (NH{sub 4}Cl), micro nutrients (Fe, Ni, Co and Mo) and leachate replacement during mono-digestion of grass silage in one-stage leach bed reactors (LBRs) enhanced hydrolysis by 18 % (0.56 g SCOD g-1 VS), 7 % (0.45 g SCOD g-1 VS) and 34 % (0.51 g SCOD g-1 VS) respectively compared to respective controls. On the other hand, creating micro-aerobic conditions (at 1 l min-1, 2.5 l of air) did not improve hydrolysis but enhanced VFA production by 4 fold (from 2.2 g l-1 to 9 g l-1). Application of rumen cultures improved hydrolysis by 10 % (0.33 g SCOD g-1 VS) more than control (0.30 g SCOD g-1 VS). Similarly, during two-stage AD in LBR-UASB reactor configuration leachate replacement enhanced hydrolysis in cucumber and grass silage (0.5 g SCOD g-1 VS) than in tomato and common reed (0.35 and 0.15 g SCOD g-1 VS respectively). During co-digestion of grass silage and cow manure at a ratio of 30:70 (VS) in CSTR, re-circulation of alkali treated solid fraction of digestate did not improve the anaerobic biodegradation rates or methane yields. Results from batch experiments showed that methane potential of grass silage varied from 0.28-0.39 m3 CH{sub 4} kg-1 VS{sub added} in all the experiments. On the other hand, methane potentials of the studied crop residues were 0.32 m3 CH{sub 4} kg-1 VS{sub added} for tomato and 0.26 m3 CH{sub 4} kg-1 VS{sub added} for cucumber and common reed. Alkali pretreatment of solids, obtained from digestate (during co-digestion of grass silage and cow manure in one-stage CSTRs), at a low concentration of 20 g NaOH kg-1 VS resulted in higher methane yield (0.34 m3 CH{sub 4} kg-1 VS{sub added}) than the other tested dosages (40 and 60 g NaOH kg-1 VS). Addition of macro nutrient (NH{sub 4}Cl) enhanced methane potential of
Why institutional environments for agroforestry seed system matters

DEFF Research Database (Denmark)

Lillesø, Jens-Peter Barnekow; Harwood, C.; Derero, Abayneh

2018-01-01

Rethinking the logic of institutional environments aiming to facilitate agroforestry smallholders in economic development, this paper compares smallholder input supply systems for crop and tree seeds in Sub-Saharan Africa and reflects on two basic challenges: (i) how to develop a large number...... of relevant tree crops for different agroecologies; (ii) how to reach smallholders in rural areas. Policy options for improving agroforestry input supply systems are discussed, whereby our article concludes with suggestions how sectoral approaches for crop seed systems can be modified to agroforestry seed......-seedling systems. Biophysical differences have practical implications for how the logic of the ‘African green revolution’ would be translated into a corresponding revolution for agroforestry....
Nitrogen and phosphorus capture and recovery efficiencies, and crop responses to a range of soil fertility management strategies in sub-Saharan Africa

NARCIS (Netherlands)

Chikowo, R.; Corbeels, M.; Mapfumo, P.; Tittonell, P.A.; Vanlauwe, B.; Giller, K.E.

2010-01-01

This paper examines a number of agronomic field experiments in different regions of sub-Saharan Africa to assess the associated variability in the efficiencies with which applied and available nutrients are taken up by crops under a wide range of management and environmental conditions. We consider
Putting mechanisms into crop production models.

Science.gov (United States)

Boote, Kenneth J; Jones, James W; White, Jeffrey W; Asseng, Senthold; Lizaso, Jon I

2013-09-01

Crop growth models dynamically simulate processes of C, N and water balance on daily or hourly time-steps to predict crop growth and development and at season-end, final yield. Their ability to integrate effects of genetics, environment and crop management have led to applications ranging from understanding gene function to predicting potential impacts of climate change. The history of crop models is reviewed briefly, and their level of mechanistic detail for assimilation and respiration, ranging from hourly leaf-to-canopy assimilation to daily radiation-use efficiency is discussed. Crop models have improved steadily over the past 30-40 years, but much work remains. Improvements are needed for the prediction of transpiration response to elevated CO₂ and high temperature effects on phenology and reproductive fertility, and simulation of root growth and nutrient uptake under stressful edaphic conditions. Mechanistic improvements are needed to better connect crop growth to genetics and to soil fertility, soil waterlogging and pest damage. Because crop models integrate multiple processes and consider impacts of environment and management, they have excellent potential for linking research from genomics and allied disciplines to crop responses at the field scale, thus providing a valuable tool for deciphering genotype by environment by management effects. © 2013 John Wiley & Sons Ltd.
Improvement of crop yield in dry environments: benchmarks, levels of organisation and the role of nitrogen.

Science.gov (United States)

Sadras, V O; Richards, R A

2014-05-01

Crop yield in dry environments can be improved with complementary approaches including selecting for yield in the target environments, selecting for yield potential, and using indirect, trait- or genomic-based methods. This paper (i) outlines the achievements of direct selection for yield in improving drought adaptation, (ii) discusses the limitations of indirect approaches in the context of levels of organization, and (iii) emphasizes trade-offs and synergies between nitrogen nutrition and drought adaptation. Selection for yield in the water- and nitrogen-scarce environments of Australia improved wheat yield per unit transpiration at a rate of 0.12kg ha(-1) mm(-1) yr(-1); for indirect methods to be justified, they must return superior rates of improvement, achieve the same rate at lower cost or provide other cost-effective benefits, such as expanding the genetic basis for selection. Slow improvement of crop adaptation to water stress using indirect methods is partially related to issues of scale. Traits are thus classified into three broad groups: those that generally scale up from low levels of organization to the crop level (e.g. herbicide resistance), those that do not (e.g. grain yield), and traits that might scale up provided they are considered in a integrated manner with scientifically sound scaling assumptions, appropriate growing conditions, and screening techniques (e.g. stay green). Predicting the scalability of traits may help to set priorities in the investment of research efforts. Primary productivity in arid and semi-arid environments is simultaneously limited by water and nitrogen, but few attempts are made to target adaptation to water and nitrogen stress simultaneously. Case studies in wheat and soybean highlight biological links between improved nitrogen nutrition and drought adaptation.

Beyond the single gene: How epistasis and gene-by-environment effects influence crop domestication.

Science.gov (United States)

Doust, Andrew N; Lukens, Lewis; Olsen, Kenneth M; Mauro-Herrera, Margarita; Meyer, Ann; Rogers, Kimberly

2014-04-29

Domestication is a multifaceted evolutionary process, involving changes in individual genes, genetic interactions, and emergent phenotypes. There has been extensive discussion of the phenotypic characteristics of plant domestication, and recent research has started to identify the specific genes and mutational mechanisms that control domestication traits. However, there is an apparent disconnect between the simple genetic architecture described for many crop domestication traits, which should facilitate rapid phenotypic change under selection, and the slow rate of change reported from the archeobotanical record. A possible explanation involves the middle ground between individual genetic changes and their expression during development, where gene-by-gene (epistatic) and gene-by-environment interactions can modify the expression of phenotypes and opportunities for selection. These aspects of genetic architecture have the potential to significantly slow the speed of phenotypic evolution during crop domestication and improvement. Here we examine whether epistatic and gene-by-environment interactions have shaped how domestication traits have evolved. We review available evidence from the literature, and we analyze two domestication-related traits, shattering and flowering time, in a mapping population derived from a cross between domesticated foxtail millet and its wild progenitor. We find that compared with wild progenitor alleles, those favored during domestication often have large phenotypic effects and are relatively insensitive to genetic background and environmental effects. Consistent selection should thus be able to rapidly change traits during domestication. We conclude that if phenotypic evolution was slow during crop domestication, this is more likely due to cultural or historical factors than epistatic or environmental constraints.
Global Crop Monitoring: A Satellite-Based Hierarchical Approach

Directory of Open Access Journals (Sweden)

Bingfang Wu

2015-04-01

Full Text Available Taking advantage of multiple new remote sensing data sources, especially from Chinese satellites, the CropWatch system has expanded the scope of its international analyses through the development of new indicators and an upgraded operational methodology. The approach adopts a hierarchical system covering four spatial levels of detail: global, regional, national (thirty-one key countries including China and “sub-countries” (for the nine largest countries. The thirty-one countries encompass more that 80% of both production and exports of maize, rice, soybean and wheat. The methodology resorts to climatic and remote sensing indicators at different scales. The global patterns of crop environmental growing conditions are first analyzed with indicators for rainfall, temperature, photosynthetically active radiation (PAR as well as potential biomass. At the regional scale, the indicators pay more attention to crops and include Vegetation Health Index (VHI, Vegetation Condition Index (VCI, Cropped Arable Land Fraction (CALF as well as Cropping Intensity (CI. Together, they characterize crop situation, farming intensity and stress. CropWatch carries out detailed crop condition analyses at the national scale with a comprehensive array of variables and indicators. The Normalized Difference Vegetation Index (NDVI, cropped areas and crop conditions are integrated to derive food production estimates. For the nine largest countries, CropWatch zooms into the sub-national units to acquire detailed information on crop condition and production by including new indicators (e.g., Crop type proportion. Based on trend analysis, CropWatch also issues crop production supply outlooks, covering both long-term variations and short-term dynamic changes in key food exporters and importers. The hierarchical approach adopted by CropWatch is the basis of the analyses of climatic and crop conditions assessments published in the quarterly “CropWatch bulletin” which
SiO{sub 2}-TiO{sub 2}-P{sub 2}O{sub 5} meso porous coatings for proton exchange membranes fuel cells; Recubrimientos meso-porosos de SiO{sub 2}-TiO{sub 2}-P{sub 2}O{sub 5} para aplicaciones en pilas de combustible de intercambio protonico

Energy Technology Data Exchange (ETDEWEB)

Castro, Y.; Mosa, J.; Duran, A.

2014-07-01

The article describes the preparation of meso porous SiO{sub 2}-TiO{sub 2}-P{sub 2}O{sub 5} coatings by Sol-Gel process combined to EISA method for using as proton exchange membranes fuel cells. Tetraethyl orthosilicate (TEOS), methyl triethoxysilane (MTES), titanium tetrachloride (TiCl{sub 4}) and phosphorus trichloride (PCl{sub 3}) have used as precursors and cetyl trimethylammonium bromide (CTAB) as porous generator agent. Films were deposited by immersion technique controlling the relative humidity at 40 and 20-70% and treated at 400 to 500 degree centigrade for 15, 30, 45 and 60 min. The variation of the refractive index and thickness have studied as a function of temperature and sintering time as well as the pore volume and density of the coatings by spectroscopic ellipsometry. Moreover, the hydrophobic/hydrophilic character of the coatings has been studied by Transform Infrared Spectroscopy (FTIR) and by contact angle measurements, following the loss of methyl groups with the temperature and sintering time. The results show that these parameters are crucial to obtain coatings with high porosity and low contact angle, important to obtain high proton conductivity conditions. The sintering conditions were fixed to 400 degree centigrade/60 min. Conductivity measurements at four points show high proton conductivity, 0,16 and 0,85 S/cm, up and down ramp, respectively, at 80 degree centigrade and 80 % of humidity. These coatings are good candidates for PEMFC membranes, if they are deposited onto electrodes. (Author)
Application of Artificial Neural Networks in Canola Crop Yield Prediction

Directory of Open Access Journals (Sweden)

S. J. Sajadi

2014-02-01

Full Text Available Crop yield prediction has an important role in agricultural policies such as specification of the crop price. Crop yield prediction researches have been based on regression analysis. In this research canola yield was predicted using Artificial Neural Networks (ANN using 11 crop year climate data (1998-2009 in Gonbad-e-Kavoos region of Golestan province. ANN inputs were mean weekly rainfall, mean weekly temperature, mean weekly relative humidity and mean weekly sun shine hours and ANN output was canola yield (kg/ha. Multi-Layer Perceptron networks (MLP with Levenberg-Marquardt backpropagation learning algorithm was used for crop yield prediction and Root Mean Square Error (RMSE and square of the Correlation Coefficient (R2 criterions were used to evaluate the performance of the ANN. The obtained results show that the 13-20-1 network has the lowest RMSE equal to 101.235 and maximum value of R2 equal to 0.997 and is suitable for predicting canola yield with climate factors.
Increased occurrence of pesticide residues on crops grown in protected environments compared to crops grown in open field conditions.

Science.gov (United States)

Allen, Gina; Halsall, Crispin J; Ukpebor, Justina; Paul, Nigel D; Ridall, Gareth; Wargent, Jason J

2015-01-01

Crops grown under plastic-clad structures or in greenhouses may be prone to an increased frequency of pesticide residue detections and higher concentrations of pesticides relative to equivalent crops grown in the open field. To test this we examined pesticide data for crops selected from the quarterly reports (2004-2009) of the UK's Pesticide Residue Committee. Five comparison crop pairs were identified whereby one crop of each pair was assumed to have been grown primarily under some form of physical protection ('protected') and the other grown primarily in open field conditions ('open'). For each pair, the number of detectable pesticide residues and the proportion of crop samples containing pesticides were statistically compared (n=100 s samples for each crop). The mean concentrations of selected photolabile pesticides were also compared. For the crop pairings of cabbage ('open') vs. lettuce ('protected') and 'berries' ('open') vs. strawberries ('protected') there was a significantly higher number of pesticides and proportion of samples with multiple residues for the protected crops. Statistically higher concentrations of pesticides, including cypermethrin, cyprodinil, fenhexamid, boscalid and iprodione were also found in the protected crops compared to the open crops. The evidence here demonstrates that, in general, the protected crops possess a higher number of detectable pesticides compared to analogous crops grown in the open. This may be due to different pesticide-use regimes, but also due to slower rates of pesticide removal in protected systems. The findings of this study raise implications for pesticide management in protected-crop systems. Copyright © 2014 Elsevier Ltd. All rights reserved.
Humidity control of an incubator using the microcontroller-based active humidifier system employing an ultrasonic nebulizer.

Science.gov (United States)

Güler, I; Burunkaya, M

2002-01-01

Relative humidity levels of an incubator were measured and controlled. An ultrasonic nebulizer system as an active humidifier was used to humidify the incubator environment. An integrated circuit-type humidity sensor was used to measure the humidity level of the incubator environment. Measurement and control processes were achieved by a PIC microcontroller. The high-performance and high-speed PIC provided the flexibility of the system. The developed system can be used effectively for the intensive care of newborns and/or premature babies. Since the humidifier generates an aerosol in ambient conditions, it is possible to provide the high relative humidity level for therapeutic and diagnostic purposes in medicine.
Soil loss estimation and prioritization of sub-watersheds of Kali River basin, Karnataka, India, using RUSLE and GIS.

Science.gov (United States)

Markose, Vipin Joseph; Jayappa, K S

2016-04-01

Most of the mountainous regions in tropical humid climatic zone experience severe soil loss due to natural factors. In the absence of measured data, modeling techniques play a crucial role for quantitative estimation of soil loss in such regions. The objective of this research work is to estimate soil loss and prioritize the sub-watersheds of Kali River basin using Revised Universal Soil Loss Equation (RUSLE) model. Various thematic layers of RUSLE factors such as rainfall erosivity (R), soil erodibility (K), topographic factor (LS), crop management factor (C), and support practice factor (P) have been prepared by using multiple spatial and non-spatial data sets. These layers are integrated in geographic information system (GIS) environment and estimated the soil loss. The results show that ∼42 % of the study area falls under low erosion risk and only 6.97 % area suffer from very high erosion risk. Based on the rate of soil loss, 165 sub-watersheds have been prioritized into four categories-very high, high, moderate, and low erosion risk. Anthropogenic activities such as deforestation, construction of dams, and rapid urbanization are the main reasons for high rate of soil loss in the study area. The soil erosion rate and prioritization maps help in implementation of a proper watershed management plan for the river basin.
PERENCANAAN PENGEMBANGAN SEKTOR PERTANIAN SUB SEKTOR TANAMAN PANGAN DI KABUPATEN KULONPROGO

Directory of Open Access Journals (Sweden)

- Fafurida

2012-01-01

Full Text Available The objective of this research is to make planning in the development of agricultural sector especiallyfood crops for the economic area improvement. The tools of analysis applied are shift share, LocationQuotient (LQ and central index analysis. The development of the superb food crops is conducted withthe development of processing and central industry. By observing the superb crops commodity, centralindex value, and PRDB per capita, it can be determined the development direction of each food cropscommodities, that is by specifying central production area and processing industry. Paddy centralproduction is recommended in Temon, Panjatan, Galur, Lendah, Kokap, Girimulyo, Nanggulan andSamigaluh sub-districts, and rice mill is developed in Wates and Pengasih sub-districts. For Maizecommodity, the development of processing industry is conducted in Sentolo and Pengasih sub-districtsand its central production is in Temon, Lendah, Kokap, Kalibawang and Samigaluh sub-districts. Forcassava crops commodity, the central production is in Temon, Kokap, Girimulyo, Kalibawang andSamigaluh sub-districts, and its processing industry is founded in Sentolo and Pengasih sub-districts.Central production of sweet potatoes is in Panjatan, Pengasih, and Girimulyo subdistricts, and itsprocessing industry is in Wates sub-district. For peanuts commodity, the processing industry is foundedin Wates and Pengasih sub-districts, and its central production is in Temon, Lendah, Kokap, Girimulyoand Samigaluh sub-districts. Central production of soybeans crops commodity is located in Temon,Galur, Lendah, Nanggulan and Kalibawang sub-districts and its processing industry is in Sentolo andPengasih sub-districts. Temon, Sentolo, and Pengasih sub-districts are the central production for thegreen beans crops with processing industry in Wates sub-district.Keywords: development, food crops, superb commodity
Aircraft observations of aerosols O{sub 3} and NO{sub y} in a nighttime urban plume

Energy Technology Data Exchange (ETDEWEB)

Berkowitz, C.M.; Zaveri, R.A.; Xindi Bian; Shiyuan Zhong; Disselkamp, R.S.; Laulainen, N.S.; Chapman, E.G. [Pacific Northwest National Lab., Richland, WA (United States)

2001-05-01

Nighttime measurements of aerosol surface area, O{sub 3}, NO{sub y} and moisture were made downwind of Portland, Oregon, as part of a study to characterize the chemistry in a nocturnal urban plume. Air parcels sampled within the urban plume soon after sunset had positive correlations between O{sub 3}, relative humidity, NO{sub y} and aerosol number density. However, the air parcels sampled within the urban plume just before dawn had O{sub 3} mixing ratios that were highly anti-correlated with aerosol number density, NO{sub y} and relative humidity. Back-trajectories from a mesoscale model show that both the post-sunset and pre-dawn parcels came from a common maritime source to the northwest of Portland. The pre-dawn parcels with strong anti-correlations passed directly over Portland in contrast to the other parcels that were found to pass west of Portland. Several gas-phase mechanisms and a heterogeneous mechanism involving the loss of O{sub 3} to the aerosol surface, are examined to explain the observed depletion in O{sub 3} within the pre-dawn parcels that had passed over Portland. (Author)
Nitrous oxide, carbon dioxide and methane emissions from irrigated cropping systems as influenced by legumes, manure and fertilizer

Energy Technology Data Exchange (ETDEWEB)

Ellert, B.H.; Janzen, H.H. [Agriculture and Agri-Food Canada, Lethbridge, AB (Canada)

2008-04-15

Irrigated crops in Alberta require higher inputs of nitrogen (N) than rainfed crops. The aim of the study was to determine emissions of nitrous oxide (N{sub 2}O) from the soils of irrigated cropping systems that used inorganic fertilizer N at a site in Alberta. The study measured carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) levels in order to determine net greenhouse gas (GHG) emissions. The exchange of gases between the atmosphere and soil in selected treatments was measured in order to compare the effects of contrasting N inputs. Fluxes were measured bi-weekly from spring 2001 to spring 2004. The time period included annual and perennial legume crops; the termination of a perennial forage crop; manure application; and 2 growing seasons of test crops. Soil surface fluxes were measured using PVC chambers equipped with thermocouples. Gas samples were measured using gas chromatography. A linear least squares method was used to calculate gas concentrations. Results showed that soil CO{sub 2} and N{sub 2}O production rates were intertwined after legume production or manure application, but decoupled during early spring bursts of N{sub 2}O production. Higher soil CO{sub 2} emissions with alfalfa and manure-amended soils suggested that soil oxygen consumption during high CO{sub 2} emission periods may promote N{sub 2}O emissions. Appreciable proportions of N{sub 2}O were emitted outside the growing season. Results suggested that N{sub 2}O leakage is an inevitable hazard of crop production. The study highlighted the importance of understanding and quantifying N{sub 2}O emissions from intensive cropping systems. 22 refs., 4 tabs., 6 figs.
Experimental performance of evaporative cooling pad systems in greenhouses in humid subtropical climates

International Nuclear Information System (INIS)

Xu, J.; Li, Y.; Wang, R.Z.; Liu, W.; Zhou, P.

2015-01-01

Highlights: • Experimental performance of evaporative cooling in humid climate is investigated. • 5 working modes are studied in the greenhouse. • Vertical and horizontal temperature and relative humidity variations are analysed. • Indoor temperature can be kept in required level by proper working modes. - Abstract: To solve the overheating problem caused by the solar radiation and to keep the indoor temperature and humidity at a proper level for plants or crops, cooling technologies play vital role in greenhouse industry, and among which evaporative cooling is one of the most commonly-used methods. However, the main challenge of the evaporative cooling is its suitability to local climatic and agronomic condition. In this study, the performance of evaporative cooling pads was investigated experimentally in a 2304-m 2 glass multi-span greenhouse in Shanghai in the southeast of China. Temperature and humidity distributions were measured and reported for different working modes, including the use of evaporative cooling alone and the use of evaporative cooling with shading or ventilation. These experiments were conducted in humid subtropical climates where were considered unfavourable for evaporative cooling pad systems. Quantified analyses from the energy perspective are also made based on the experimental results and the evaporative cooling fan–pad system is demonstrated to be an effective option for greenhouse cooling even in the humid climate. Suggestions and possible solutions for further improving the performance of the system are proposed. The results of this work will be useful for the optimisation of the energy management of greenhouses in humid climates and for the validation of the mathematical model in future work
Smallholder Irrigation and Crop Diversification under Climate Change in sub-Saharan Africa: Evidence and Potential for Simultaneous Food Security, Adaptation, and Mitigation

Science.gov (United States)

Naylor, R.; Burney, J. A.; Postel, S.

2011-12-01

The poorest populations in sub-Saharan Africa live in rural areas and depend on smallholder agricultural production for their livelihoods. Over 90% of all farmed area in Sub-Saharan Africa is rainfed, with crop production centering on 3-5 months of rainfall. Rapid population growth is reducing land per capita ratios, and low yields for staple crops make food security an increasingly challenging goal. Malnutrition, most noticeable among children, peaks during the dry season. Recent data on aggregate economic growth and investment in Africa hide these patterns of seasonal hunger and income disparity. Perhaps most perversely, smallholder farmers in the dry tropical regions of sub-Saharan Africa are (and will continue to be) some of the earliest and hardest hit by climate change. Our research focuses on the role distributed, small-scale irrigation can play in food security and climate change adaptation in sub-Saharan Africa. As Asia's agricultural success has demonstrated, irrigation, when combined with the availability of inputs (fertilizer) and improved crop varieties, can enable year-round production, growth in rural incomes, and a dramatic reduction in hunger. The situation in Africa is markedly different: agroecological conditions are far more heterogeneous than in Asia and evaporation rates are relatively high; most smallholders lack access to fertilizers; and market integration is constrained by infrastructure, information, and private sector incentives. Yet from a resource perspective, national- and regional-level estimates suggest that Internal Renewable Water Resources (IRWR) are nowhere near fully exploited in Sub-Saharan Africa -- even in the Sudano-Sahel, which is considered to be one of the driest regions of the continent. Irrigation can thus be implemented on a much larger scale sustainably. We will present (a) results from controlled, experimental field studies of solar-powered drip irrigation systems in the rural Sudano-Sahel region of West Africa. We
High accuracy acoustic relative humidity measurement in duct flow with air.

Science.gov (United States)

van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

2010-01-01

An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.
Methods of humidity determination Part II: Determination of material humidity

OpenAIRE

Rübner, Katrin; Balköse, Devrim; Robens, E.

2008-01-01

Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.
Rising atmospheric CO{sub 2} and crops: Research methodology and direct effects

Energy Technology Data Exchange (ETDEWEB)

Rogers, H. [National Soil Dynamics Laboratory, Auburn, AL (United States); Acock, B. [Systems Research Laboratory, Beltsville, MD (United States)

1993-12-31

Carbon dioxide is the food of trees and grass. Our relentless pursuit of a better life has taken us down a traffic jammed road, past smoking factories and forests. This pursuit is forcing a rise in the atmospheric CO{sub 2} level, and no one know when and if flood stage will be reached. Some thinkers have suggested that this increase of CO{sub 2} in the atmosphere will cause warming. No matter whether this prediction is realized or not, more CO{sub 2} will directly affect plants. Data from controlled observations have usually, but not always, shown benefits. Our choices of scientific equipment for gathering CO{sub 2} response data are critical since we must see what is happening through the eye of the instrument. The signals derived from our sensors will ultimately determine the truth of our conclusions, conclusion which will profoundly influence our policy decisions. Experimental gear is selected on the basis of scale of interest and problem to be addressed. Our imaginations and our budgets interact to set bounds on our objectives and approaches. Techniques run the gamut from cellular microprobes through whole-plant controlled environment chambers to field-scale exposure systems. Trade-offs exist among the various CO{sub 2} exposure techniques, and many factors impinge on the choice of a method. All exposure chambers are derivatives of three primary types--batch, plug flow, and continuous stirred tank reactor. Systems for the generation of controlled test atmospheres of CO{sub 2} vary in two basic ways--size and degree of control. Among the newest is free-air CO{sub 2} enrichment which allows tens of square meters of cropland to be studied.
Effects of humidity and interlayer cations on the frictional strength of montmorillonite

Science.gov (United States)

Tetsuka, Hiroshi; Katayama, Ikuo; Sakuma, Hiroshi; Tamura, Kenji

2018-04-01

We developed a humidity control system in a biaxial friction testing machine to investigate the effect of relative humidity and interlayer cations on the frictional strength of montmorillonite. We carried out the frictional experiments on Na- and Ca-montmorillonite under controlled relative humidities (ca. 10, 30, 50, 70, and 90%) and at a constant temperature (95 °C). Our experimental results show that frictional strengths of both Na- and Ca-montmorillonite decrease systematically with increasing relative humidity. The friction coefficients of Na-montmorillonite decrease from 0.33 (at relative humidity of 10%) to 0.06 (at relative humidity of 93%) and those of Ca-montmorillonite decrease from 0.22 (at relative humidity of 11%) to 0.04 (at relative humidity of 91%). Our results also show that the frictional strength of Na-montmorillonite is higher than that of Ca-montmorillonite at a given relative humidity. These results reveal that the frictional strength of montmorillonite is sensitive to hydration state and interlayer cation species, suggesting that the strength of faults containing these clay minerals depends on the physical and chemical environment.[Figure not available: see fulltext.
EPR, mu-Raman and Crystallographic properties of spinel type ZnCr{sub 2}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Vargas-Hernandez, C; Almanza, O; Jurado, J F, E-mail: cvargash@unal.edu.c [Universidad Nacional de Colombia, Manizales-Colombia Laboratorio de Propiedades Opticas de Materiales-POM (Colombia)

2009-05-01

Structural, vibrational and electron paramagnetic resonance (EPR) analysis for compound ZnCr{sub 2}O{sub 4} are shown in this work. These types of materials are used in technological applications as humidity sensors and piezoelectric devices. The compound was obtained by mean of solid state reaction technique from binary precursors ZnO and Cr{sub 2}O{sub 3}. After three thermal treatments the sample structure was monitoring using X ray diffraction (XRD), the spinel cubic phase has been indexed within O{sup 7}{sub h}(Fd3m) spatial group. It is observed normal spinel phase. Micro-Raman analysis revealed bands for normal vibration modes of Zn and Cr atoms in tetrahedral and octahedral environments formed by oxygen atoms at approximately 400 and 900 cm{sup -1}, respectively. Bands around 941 cm{sup -1} are associated possibly to vacancies in the tetrahedral and octahedral sites due to interaction between Zn and Cr ions. EPR signal from 150 to 300 K isothermals indicates a transition between inverse spinel to normal spinel type in a central field around 3350 G. A signal at approximately 3400 G corresponding to the C'r{sup +3} in tetrahedral sites is observed near the central field.
The role of tolerant genotypes and plant nutrients in the management of acid soil infertility in upland rice

International Nuclear Information System (INIS)

Sahrawat, K.L.; Jones, M.P.; Diatta, S.

2000-01-01

As in other parts of the humid tropics, acid-related problems are the major constraint to crop production on low-activity clay soils in the humid and sub-humid zones of West Africa. The upland ecosystem of West Africa is very important to rice production. About 70% of upland rice is grown in the humid zone of the sub-region. To increase and stabilize rice productivity of the acid uplands at reasonable levels, a strategy is needed that integrates the use of tolerant cultivars with soil and plant-nutrient management. Research conducted on Alfisols and Ultisols of the humid-forest and savannah zones in West Africa showed that upland rice is a robust crop, possessing a wide range of tolerance to acid-soil conditions. Recent research at WARDA showed also that acid-soil tolerance can be enhanced through interspecific Oryza sativa x O. glaberrima progenies, which not only possess increased tolerance of acid-soil conditions, but also have superior overall adaptability to diverse upland environments in the sub-region. Our research on the diagnosis of acid-soil infertility problems on the Ultisols and Alfisols of the humid savannah and forest zones indicates that P deficiency is the most important nutrient disorder for upland rice. In the forest zone, response to N depended on the application of P. In the savannah and forest-savannah transition zones, N deficiency was more important than P deficiency. Among other plant nutrients, the application of Ca and Mg (as plant nutrients) did not appear initially to improve the performance of acid-tolerant upland rice cultivars. The results from a long-term study on an Ultisol with four acid-tolerant rice cultivars, revealed that they differed in agronomic and physiological P efficiencies, and the efficiencies were higher at lower rates of P. The amounts of total P removed in three successive crops were similar for all four cultivars although P-harvest index was 10 to 12% higher in the P-efficient than the inefficient cultivars. The
The Design of Temperature and Humidity Chamber Monitor and Controller

OpenAIRE

Tibebu, Simachew

2016-01-01

The temperature and humidity chamber, (climate chamber) is a device located at the Technobothnia Education and Research Center that simulates different climate conditions. The simulated environment is used to test the capabilities of electrical equipment in different temperature and humidity conditions. The climate chamber, among other things houses a dedicated computer, the control PC, and a control software running in it which together are responsible for running and control-ling these simu...
High Accuracy Acoustic Relative Humidity Measurement inDuct Flow with Air

Directory of Open Access Journals (Sweden)

Cees van der Geld

2010-08-01

Full Text Available An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

Improved running performance in hot humid conditions following whole body precooling.

Science.gov (United States)

Booth, J; Marino, F; Ward, J J

1997-07-01

On two separate occasions, eight subjects controlled speed to run the greatest distance possible in 30 min in a hot, humid environment (ambient temperature 32 degrees C, relative humidity 60%). For the experimental test (precooling), exercise was preceeded by cold-water immersion. Precooling increased the distance run by 304 +/- 166 m (P body temperature decreased from 36.5 +/- 0.1 degrees C to 33.8 +/- 0.2 degrees C following precooling (P body sweating are not different between tests. In conclusion, water immersion precooling increased exercise endurance in hot, humid conditions with an enhanced rate of heat storage and decreased thermoregulatory strain.
The development and application of a sub-channel code in ocean environment

International Nuclear Information System (INIS)

Wu, Pan; Shan, Jianqiang; Xiang, Xiong; Zhang, Bo; Gou, Junli; Zhang, Bin

2016-01-01

Highlights: • A sub-channel code named ATHAS/OE is developed for nuclear reactors in ocean environment. • ATHAS/OE is verified by another modified sub-channel code based on COBRA-IV. • ATHAS/OE is used to analyze thermal hydraulic of a typical SMR in heaving and rolling motion. • Calculation results show that ocean condition affect the thermal hydraulic of a reactor significantly. - Abstract: An upgraded version of ATHAS sub-channel code ATHAS/OE is developed for the investigation of the thermal hydraulic behavior of nuclear reactor core in ocean environment with consideration of heaving and rolling motion effect. The code is verified by another modified sub-channel code based on COBRA-IV and used to analyze the thermal hydraulic characteristics of a typical SMR under heaving and rolling motion condition. The calculation results show that the heaving and rolling motion affect the thermal hydraulic behavior of a reactor significantly.
Malabsorption of mineral nutrients and effects of foliar fertilization on continuously cropped capsicum annuum l. var. annuum

International Nuclear Information System (INIS)

Ye, X.H.; Zhao, Z.L.; Zhao, Z.L.; Zhao, H.B.

2014-01-01

Cayenne pepper (C. annuum var. annuum) cultivar known as line No. 5 was used to establish a reference baseline for fertilization experiments under conditions of continuous cropping versus crop rotation. The effects of continuous cropping on absorption of 11 essential nutrient elements and fruit yield were studied. Concurrently, we also examined the effects of foliar application of urea + KH/sub 2/ PO/sub 4/ and Fe + B + Zn + Mn on nutrient absorption due to continuous cropping. The results showed that, compared with peppers grown in rotation soil, continuous cropping affected the uptake of eight elements (P, K, Mg, Fe, B, Zn, Mn, Cu) and transport of these elements to the aerial parts of the plant, although the element concentrations in continuous cropping soil were not lower than those in rotation soil. Continuous cropping caused a decline in fruit yield. The impact of continuous cropping on the uptake of trace elements was greater than it was for macro elements. Foliar application of urea + KH/sub 2/ PO/sub 4/ significantly improved the P, Mg, Fe, and Mo content of continuously-cropped pepper plants, but did not significantly improve the content of N and K, and there was an antagonistic effect on Zn uptake. Foliar application of Fe + B + Zn + Mn, significantly increased the Fe, B, Zn, Mn, and P content in the plants; Ca uptake in the leaves and fruits was promoted to a certain degree, but there was obvious antagonism toward Mo and Cu uptake in the stems, leaves and fruits. Pepper fruit yields were significantly increased by foliar application of urea + KH/sub 2/ PO/sub 4/ or foliar application of Fe + B + Zn + Mn. However the effects of foliar application of Fe + B + Zn + Mn on increased production were significantly better than the effects of foliar application of urea + KH/sub 2/ PO/sub 4/. (author)
Electrical, magnetic and physical properties of YBa/sub 2/Cu/sub 3/O/sub 7-x/ superconductor/polymer composites

International Nuclear Information System (INIS)

Fuierer, P.A.; Srinivasan, T.T.; Newnham, R.E.

1988-01-01

A polymer matrix provides a composite with flexibility and improved impact strength as well as protection against humidity and chemical attack. Superconductor/polymer 0-3 composites have been prepared by mixing YBa/sub 2/Cu/sub 3/O/sub 7-x/ powder with silicone rubber, pressing and curing. The resistivities of these composites do not go to zero, however, the magnetic flux exclusion is maintained in the temperature range, T< T/sub c/(--91K). The composite resistivities show percolation behavior and diamagnetism increases with increasing volume fraction of the superconductor filler. The composites exhibit levitation and large diamagnetic susceptibilities
Integrated crop management practices for maximizing grain yield of double-season rice crop

Science.gov (United States)

Wang, Depeng; Huang, Jianliang; Nie, Lixiao; Wang, Fei; Ling, Xiaoxia; Cui, Kehui; Li, Yong; Peng, Shaobing

2017-01-01

Information on maximum grain yield and its attributes are limited for double-season rice crop grown under the subtropical environment. This study was conducted to examine key characteristics associated with high yielding double-season rice crop through a comparison between an integrated crop management (ICM) and farmers’ practice (FP). Field experiments were conducted in the early and late seasons in the subtropical environment of Wuxue County, Hubei Province, China in 2013 and 2014. On average, grain yield in ICM was 13.5% higher than that in FP. A maximum grain yield of 9.40 and 10.53 t ha-1 was achieved under ICM in the early- and late-season rice, respectively. Yield improvement of double-season rice with ICM was achieved with the combined effects of increased plant density and optimized nutrient management. Yield gain of ICM resulted from a combination of increases in sink size due to more panicle number per unit area and biomass production, further supported by the increased leaf area index, leaf area duration, radiation use efficiency, crop growth rate, and total nitrogen uptake compared with FP. Further enhancement in the yield potential of double-season rice should focus on increasing crop growth rate and biomass production through improved and integrated crop management practices.
Evaluating thermal image sharpening over irrigated crops in a desert environment

KAUST Repository

Rosas, Jorge

2014-09-01

Satellite remote sensing provides spatially and temporally distributed data on land surface characteristics, useful for mapping land surface energy fluxes and evapotranspiration (ET). Multi-spectral platforms, including Landsat and the Moderate Resolution Imaging Spectroradiometer (MODIS), acquire imagery in the visible to shortwave infrared and thermal infrared (TIR) domain at resolutions ranging from 30 to 1000 m. Land-surface temperature (LST) derived from TIR satellite data has been reliably used as a remote indicator of ET and surface moisture status. However, TIR imagery usually operates at a coarser resolution than that of shortwave sensors on the same satellite platform, making it sometimes unsuitable for monitoring of field-scale crop conditions. As a result, several techniques for thermal sharpening have been developed. In this study, the data mining sharpener (DMS; Gao et al., 2012) technique is applied over irrigated farming areas located in harsh desert environments in Saudi Arabia. The DMS approach sharpens TIR imagery using finer resolution shortwave spectral reflectances and functional LST and reflectance relationships established using a flexible regression tree approach. In this study, the DMS is applied to Landsat 8 data (100m TIR resolution), which is scaled up to 240m, 480m, and 960m in order to assess the accuracy of the DMS technique in arid irrigated farming environments for different sharpening ratios. Furthermore, the scaling done on Landsat 8 data is consistent with the resolution of MODIS products. Potential enhancements to DMS are investigated including the use of ancillary terrain data. Finally, the impact of using sharpened LST, as input to a two-source energy balance model, on simulated ET will be evaluated. The ability to accurately monitor field-scale changes in vegetation cover, crop conditions and surface fluxes, are of main importance towards an efficient water use in areas where fresh water resources are scarce and poorly
Water, soil, crops and radionuclides. Studies on the behavior of radionuclides in the terrestrial environments

International Nuclear Information System (INIS)

Uchida, Shigeo

2008-01-01

In order to predict the migration of artificially-produced radionuclides into a human body and its radiation dose rates of human body and to decrease the exposed radiation doses of human body, the behavior of radionuclides in the environment must be elucidated. In National Institute of Radiological Sciences (NIRS), the environmental radioecological research group of Nakaminato Laboratory for Marine Radioecology has progressed the survey and research on the behavior of artificially-produced radionuclides in the terrestrial environment. This article describes the research results (the radioactivity of water, soil, and crops) made so far at Nakaminato Laboratory for Marine Radioecology. (M.H.)
The role of carbonic anhydrase in C4sub> photosynthesis

Energy Technology Data Exchange (ETDEWEB)

Studer, Anthony [Life Sciences Research Foundation, Baltimore, MD (United States)

2015-10-01

Current pressures on the global food supply have accelerated the urgency for a second green revolution using novel and sustainable approaches to increase crop yield and efficiency. This proposal outlines experiments to address fundamental questions regarding the biology of C4sub> photosynthesis, the method of carbon fixation utilized by the most productive food, feed and bioenergy crops. Carbonic anhydrase (CA) has been implicated in multiple cellular functions including nitrogen metabolism, water use efficiency, and photosynthesis. CA catalyzes the first dedicated step in C4sub> photosynthesis, the hydration of CO2sub> into bicarbonate, and is potentially rate limiting in C4sub> grasses. Using insertional mutagenesis, we have generated CA mutants in maize, and propose the characterization of these mutants using phenotypic, physiological, and transcriptomic profiling to assay the plant’s response to altered CA activity. In addition, florescent protein tagging experiments will be employed to study the subcellular localization of CA paralogs, providing critical data for modeling carbon fixation in C4sub> plants. Finally, I propose parallel experiments in Setaria viridis to explore its relevance as model C4sub> grass. Using a multifaceted approach, this proposal addresses important questions in basic biology, as well as the need for translation research in response to looming global food challenges.
Direct nitrous oxide emissions in Mediterranean climate cropping systems

NARCIS (Netherlands)

Cayuela, Maria L.; Aguilera, Eduardo; Sanz-Cobena, Alberto; Adams, Dean C.; Abalos Rodriguez, Diego; Barton, Louise; Ryals, Rebecca; Silver, Whendee L.; Alfaro, Marta A.; Pappa, Valentini A.; Bouwman, Lex; Lassaletta, Luis

2017-01-01

Many recent reviews and meta-analyses of N2sub>O emissions do not include data from Mediterranean studies. In this paper we present a meta-analysis of the N2sub>O emissions from Mediterranean cropping systems, and propose a more robust and reliable regional emission factor (EF) for
Thermal Comfort and Optimum Humidity Part 1

Directory of Open Access Journals (Sweden)

M. V. Jokl

2002-01-01

Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.
Thermal Comfort and Optimum Humidity Part 2

Directory of Open Access Journals (Sweden)

M. V. Jokl

2002-01-01

Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.
Differential effects of elevated air humidity on stomatal closing ability of Kalanchoë blossfeldiana between the C

NARCIS (Netherlands)

Fanourakis, Dimitrios; Hyldgaard, Benita; Gebraegziabher, Habtamu; Bouranis, Dimitris; Körner, Oliver; Nielsen, Kai Lønne; Ottosen, Carl-Otto

2017-01-01

High relative air humidity (RH ≥ 85%) impairs stomatal functionality, attenuating plant capacity to cope with abiotic stress. Previous studies were limited to C3sub> species, so the RH effect on stomatal physiology of CAM plants remains unexplored. We addressed the topic through
Utilization of male sterility in forage crops

Energy Technology Data Exchange (ETDEWEB)

Suginobu, Ken-ichi [National Grassland Research Inst., Nishinasuno, Tochigi (Japan)

1982-03-01

The genetic nature of male sterility in forage crops was reviewed. Many workers have suggested that hybrids in forage crops are quite promising. First, the selection of the most desirable parental genotype from a large original population is improtant in heterosis breeding programs. After the more promising inbreds or clones have been selected on the basis of good general combining ability, it is necessary to identify the particular single, three-way or double cross that will produce the highest yields. A high seed yield potential is also important in a new variety so that the seeds can be sold at lower prices than other varieties. A tentative scheme for hybrid seed production by using inbred lines of male sterile or normal parents is proposed. At a breeding station, the seeds for male sterile F/sub 1/(AB), maintainer S/sub 1/(C-S/sub 1/) and either maintainer or restorer S/sub 1/s(D-S/sub 1/, E-S/sub 1/) are produced from the parental clones. At a seed increase agency, the seeds for male sterile F/sub 1/(ABC) and either maintainer or restorer S/sub 2/(D-S/sub 2/) are produced. In the case that D-S/sub 2/ seed production is difficult, maintainer or restorer F/sub 1/(DE) should be produced from D-S/sub 1/ x E-S/sub 1/. These seeds are used for commercial seed production. Seeds of hybrid F/sub 1/(ABCD) or hybrid F/sub 1/(ABCDE) are for practical use.
Disentangling the positive and negative effects of trees on maize performance in smallholdings of Northern Rwanda

NARCIS (Netherlands)

Ndoli, Alain; Baudron, Frédéric; Schut, Tom; Mukuralinda, Athanase; Giller, Ken E.

2017-01-01

In the sub-humid parts of East Africa, high population density and pressure on land have led farmers to integrate multipurpose trees on farm. Although mixing trees and crops generates numerous benefits (e.g., fuelwood, timber), it often reduces crop yields. Whereas the effects of mature trees on
On the variations of strength of the CO sub 2 -silicate mould. CO sub 2 igata no kyodo henka ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Takano, Kenzo; Natori, Yoshikatsu; Suganuma, Sadao (Koei Co., Ltd., Saitama, (Japan) Nippon Chemical Industrial Co., Ltd., Tokyo, (Japan))

1990-01-25

Moulds prepared by uniform hardening were stored in normal foundry atmosphere and in the humidity controlled chamber to investigate properties of mould. Then, the relationship between the reaction rate of CO {sub 2} and Na {sub 2} 0 contained in mould binder and mould strength was studied. Followings were found: Turning point between absorption and desorption of mould exsits between 81-83% relative humidity (RH). Under the hith RH of the turning point or more, more the water glass addition, more the absorbed amount. When moulds were stored in the humidity controlled chamber, close relation was found between RH%, desorption or absorption rate and mould strength, that is, higher the desorption rate, higher the strength. Further, the reversible relationship was found between the strength and absorpion or desorption rate. Although any deterioration of strength was not found for moulds stored in the humidity controlled chamber (RH of 44-81%), moulds stored in normal foundry stmosphere lost the strength or deteriorated gradually. 7 refs., 11 figs., 2 tabs.
Dynamic Predictions of Crop Yield and Irrigation in Sub-Saharan Africa Due to Climate Change Impacts

Science.gov (United States)

Foster-Wittig, T.

2012-12-01

The highest damages from climate change are predicted to be in the agricultural sector in sub-Saharan Africa. Agriculture is predicted to be especially vulnerable in this region because of its current state of high temperature and low precipitation and because it is usually rain-fed or relies on relatively basic technologies which therefore limit its ability to sustain in increased poor climatic conditions [1]. The goal of this research is to quantify the vulnerability of this ecosystem by projecting future changes in agriculture due to IPCC predicted climate change impacts on precipitation and temperature. This research will provide a better understanding of the relationship between precipitation and rain-fed agriculture in savannas. In order to quantify the effects of climate change on agriculture, the impacts of climate change are modeled through the use of a land surface vegetation dynamics model previously developed combined with a crop model [2,4]. In this project, it will be used to model yield for point cropland locations within sub-Saharan Africa between Kenya and Botswana with a range of annual rainfall. With this model, future projections are developed for what can be anticipated for the crop yield based on two precipitation climate change scenarios; (1) decreased depth and (2) decreased frequency as well as temperature change scenarios; (3) only temperature increased, (4) temperature increase dand decreased precipitation depth, and (5) temperature increased and decreased precipitation frequency. Therefore, this will allow conclusions to be drawn about how mean precipitation and a changing climate effect food security in sub-Saharan Africa. As an additional analysis, irrigation is added to the model as it is thought to be the solution to protect food security by maximizing on the potential of food production. In water-limited areas such as Sub-Saharan Africa, it is important to consider water efficient irrigation techniques such as demand-based micro
Maximizing growth of vegetable seedlings in controlled environments at elevated temperature, light and CO/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Krizek, D.T.; Bailey, W.A.; Klueter, H.; Liu, R.C.

1974-01-01

Seedlings of cucumber Burpee Hybrid, tomato Michigan-Ohio and lettuce Grand Rapids were germinated in the greenhouse for 5, 8, and 11 days respectively, and then grown for 15 days at elevated temperature (30/24/sup 0/C), light (43.1 klx), and CO/sub 2/ (2000 ppm) a 16-hr photoperiod, 65% relative humidity, and fertilized 4 times daily. At the end of this time, they weighed 2 to 4.6 times those grown at standard environmental conditions in the growth chamber (24/18/sup 0/C, 21.5 klx, and 400 ppm CO/sub 2/) and 10 to 25 times those of greenhouse controls kept on natural days (24/18/sup 0/C, 350 ppm CO/sub 2/, and ca 12-hr photoperiod). Leaf expansion of seedlings grown under elevated growth chamber conditions was double that of seedlings in standard growth chamber conditions, and 6 to 7 times greater than under natural days in the greenhouse. Temperature was the most limiting factor for seedling growth. At the levels of light and CO/sub 2/ used in the experiment, CO/sub 2/ was more limiting than light intensity. In general, optimum seedling growth was obtained when temperature, light, and CO/sub 2/ were increased simultaneously. The most striking effects of CO/sub 2/ enrichment were precocious flower bud formation in tomato and cucumber and extensive growth of the lateral buds in all three species.
Characterization of spacecraft humidity condensate

Science.gov (United States)

Muckle, Susan; Schultz, John R.; Sauer, Richard L.

1994-01-01

When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.
A nafion coated capacitive humidity sensor on a flexible PET substrate

KAUST Repository

Sapsanis, Christos

2017-03-07

This paper reports a simple and low-cost technique for fabricating low-power capacitive humidity sensors without the use of a cleanroom environment. A maskless laser engraving system was utilized to fabricate two different gold electrode structures, interdigitated electrodes and Hilbert\\'s fifth-order fractal. The capacitive structures were implemented on a flexible PET substrate. The usage of Nafion, a well-known polymer for its hydrophilic properties as a sensing film, was attempted on the PET and outperformed the current efforts in flexible substrates. Its humidity sensing properties were evaluated in an automated gas setup with a relative humidity (RH %) ranging from 15% to 95 %.
A nafion coated capacitive humidity sensor on a flexible PET substrate

KAUST Repository

Sapsanis, Christos; Buttner, Ulrich; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Eddaoudi, Mohamed; Salama, Khaled N.

2017-01-01

This paper reports a simple and low-cost technique for fabricating low-power capacitive humidity sensors without the use of a cleanroom environment. A maskless laser engraving system was utilized to fabricate two different gold electrode structures, interdigitated electrodes and Hilbert's fifth-order fractal. The capacitive structures were implemented on a flexible PET substrate. The usage of Nafion, a well-known polymer for its hydrophilic properties as a sensing film, was attempted on the PET and outperformed the current efforts in flexible substrates. Its humidity sensing properties were evaluated in an automated gas setup with a relative humidity (RH %) ranging from 15% to 95 %.

Sub-tropical urban environment affecting content and composition of non-structural carbohydrates of Lolium multiflorum ssp. italicum cv. Lema

International Nuclear Information System (INIS)

Sandrin, Carla Zuliani; Figueiredo-Ribeiro, Rita de Cassia Leone; Carvalho, Maria Angela Machado de; Carvalho Delitti, Welington Braz; Domingos, Marisa

2008-01-01

This study analyzed the relationship between environmental factors, especially air pollution and climatic conditions, and non-structural carbohydrates (NSC) in plants of Lolium multiflorum exposed during 10 consecutive periods of 28 days at a polluted site (Congonhas) and at a reference site in Sao Paulo city (Brazil). After exposure, NSC composition and leaf concentrations of Al, Fe, Cu, Zn, Pb and Cd were measured. The seasonal pattern of NSC accumulation was quite similar in both sites, but plants at Congonhas showed higher concentrations of these compounds, especially fructans of low and medium degree of polymerization. Regression analysis showed that NSC in plants growing at the polluted site were explained by variations on temperature and leaf concentration of Fe (positive effect), as well as relative humidity and particulate material (negative effect). NSC in the standardized grass culture, in addition to heavy metal accumulation, may indicate stressing conditions in a sub-tropical polluted environment. - Particulate matter and air temperature increased non-structural carbohydrates in the standardized biomonitor grass in Sao Paulo
Sub-tropical urban environment affecting content and composition of non-structural carbohydrates of Lolium multiflorum ssp. italicum cv. Lema

Energy Technology Data Exchange (ETDEWEB)

Sandrin, Carla Zuliani; Figueiredo-Ribeiro, Rita de Cassia Leone; Carvalho, Maria Angela Machado de [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Carvalho Delitti, Welington Braz [Instituto de Biociencias, Universidade de Sao Paulo, Departamento de Ecologia, Caixa Postal 11461, 05422-970 Sao Paulo, SP (Brazil); Domingos, Marisa [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil)], E-mail: mmingos@superig.com.br

2008-12-15

This study analyzed the relationship between environmental factors, especially air pollution and climatic conditions, and non-structural carbohydrates (NSC) in plants of Lolium multiflorum exposed during 10 consecutive periods of 28 days at a polluted site (Congonhas) and at a reference site in Sao Paulo city (Brazil). After exposure, NSC composition and leaf concentrations of Al, Fe, Cu, Zn, Pb and Cd were measured. The seasonal pattern of NSC accumulation was quite similar in both sites, but plants at Congonhas showed higher concentrations of these compounds, especially fructans of low and medium degree of polymerization. Regression analysis showed that NSC in plants growing at the polluted site were explained by variations on temperature and leaf concentration of Fe (positive effect), as well as relative humidity and particulate material (negative effect). NSC in the standardized grass culture, in addition to heavy metal accumulation, may indicate stressing conditions in a sub-tropical polluted environment. - Particulate matter and air temperature increased non-structural carbohydrates in the standardized biomonitor grass in Sao Paulo.
Initial stages of indoor atmospheric corrosion of electronics contact metals in humid tropical climate: tin and nickel

Directory of Open Access Journals (Sweden)

Veleva, L.

2007-04-01

Full Text Available Samples of electrolytic tin and nickel have been exposed for 1 to 12 m in indoor environment, inside a box (rain sheltered cabinet, placed in tropical humid marine-urban climate, as a part of Gulf of Mexico. The corrosion aggressiveness of box has been classified as a very high corrosive, based on the monitored chlorides and SO2sub> deposition rates, and the Temperature/Relative Humidity air daily complex. The annual mass increasing of nickel is approximately twice higher than its values of mass loss (C. The relation between nickel mass loss or increasing and time of wetness (t of metal surface is linear and does not obey the power equation C = A tⁿ, which has be found for tin. The SEM images reveal a localized corrosion on nickel and tin surfaces. XRD detects the formation of SnCl2sub>.H>2sub>O as a corrosion product. Within the time on the tin surface appear black spots, considered as organic material.

Muestras de estaño y níquel electrolíticos han sido expuestas de 1 a 12 m en ambiente interno (indoor, en una caseta (gabinete protegido de lluvia, colocada en clima tropical húmedo marino-urbano del Golfo de México. La agresividad de la caseta ha sido clasificada como muy altamente corrosiva, basada al registro de la velocidad de deposición de cloruros y SO2sub>, y en el complejo diario de temperatura/humedad relativa del aire. El incremento de masa anual de níquel es, aproximadamente, dos veces mayor que del valor de su pérdida de masa (C. La relación entre la pérdida de masa de Ni o su incremento, y el tiempo de humectación (t de la superficie metálica y lineal y no obedece la ley de potencia C = A tⁿ , que ha sido encontrada para el estaño. Las imágenes del SEM revelan una corrosión localizada en las superficie de níquel y estaño. El análisis de rayos-X detecta la formación de SnCl2sub>.H>2sub>O como producto de corrosión. Con el tiempo
Predicting optimum crop designs using crop models and seasonal climate forecasts.

Science.gov (United States)

Rodriguez, D; de Voil, P; Hudson, D; Brown, J N; Hayman, P; Marrou, H; Meinke, H

2018-02-02

Expected increases in food demand and the need to limit the incorporation of new lands into agriculture to curtail emissions, highlight the urgency to bridge productivity gaps, increase farmers profits and manage risks in dryland cropping. A way to bridge those gaps is to identify optimum combination of genetics (G), and agronomic managements (M) i.e. crop designs (GxM), for the prevailing and expected growing environment (E). Our understanding of crop stress physiology indicates that in hindsight, those optimum crop designs should be known, while the main problem is to predict relevant attributes of the E, at the time of sowing, so that optimum GxM combinations could be informed. Here we test our capacity to inform that "hindsight", by linking a tested crop model (APSIM) with a skillful seasonal climate forecasting system, to answer "What is the value of the skill in seasonal climate forecasting, to inform crop designs?" Results showed that the GCM POAMA-2 was reliable and skillful, and that when linked with APSIM, optimum crop designs could be informed. We conclude that reliable and skillful GCMs that are easily interfaced with crop simulation models, can be used to inform optimum crop designs, increase farmers profits and reduce risks.
The influence of included minerals on the intrinsic reactivity of chars prepared under N{sub 2} and CO{sub 2} environment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hong; Li, Huan; Chen, Jiabao; Zhao, Bo; Hu, Guangzhou [China Univ. of Mining and Technology, Jiangsu (China). School of Chemical Engineering

2013-07-01

Oxy-fuel technology could be successfully used to retrofit existing coal-fired power plants or alternatively be used to design and build new coal-fired power plants with almost zero emissions. Char reactivity under oxy-fuel conditions will have a significant impact on the coal burnout. In this paper, two fractions, representing organic-rich particles and organic particles with included minerals, were separated from each of three Chinese coals of different rank. They were then devolatilized at 1,450 C in a drop tube furnace (DTF) under N{sub 2} and CO{sub 2} environment, respectively. The chars were subjected to nitrogen adsorption study, thermogravimetric analysis and XRD analysis. It was found that char reactivity of all three pairs of chars were increased under CO{sub 2} environment as compared with that under N{sub 2} environment, but with differing trend. For the organic-rich samples the reactivity difference is increased with decreasing rank. On the contrary, for the samples of organic particles with included minerals, the reactivity difference is decreased with decreasing rank. Mechanism analysis showed that they are resulted not from gasification, but from a combination of changes in surface area and in the orderness of carbon structure in the chars, both of which, in turn, are resulted from the higher heat capacity of CO{sub 2} and the interaction between metastable liquid phase and the included minerals.
Comparative proteomic analysis of the thermotolerant plant Portulaca oleracea acclimation to combined high temperature and humidity stress.

Science.gov (United States)

Yang, Yunqiang; Chen, Jinhui; Liu, Qi; Ben, Cécile; Todd, Christopher D; Shi, Jisen; Yang, Yongping; Hu, Xiangyang

2012-07-06

Elevated temperature and humidity are major environmental factors limiting crop yield and distribution. An understanding of the mechanisms underlying plant tolerance to high temperature and humidity may facilitate the development of cultivars adaptable to warm or humid regions. Under conditions of 90% humidity and 35 °C, the thermotolerant plant Portulaca oleracea exhibits excellent photosynthetic capability and relatively little oxidative damage. To determine the proteomic response that occurs in leaves of P. oleracea following exposure to high temperature and high humidity, a proteomic approach was performed to identify protein changes. A total of 51 differentially expressed proteins were detected and characterized functionally and structurally; these identified proteins were involved in various functional categories, mainly including material and energy metabolism, the antioxidant defense responses, protein destination and storage, and transcriptional regulation. The subset of antioxidant defense-related proteins demonstrated marked increases in activity with exposure to heat and humidity, which led to lower accumulations of H(2)O(2) and O(2)(-) in P. oleracea compared with the thermosensitive plant Arabidopsis thaliana. The quickly accumulations of proline content and heat-shock proteins, and depleting abscisic acid (ABA) via increasing ABA-8'-hydroxylase were also found in P. oleracea under stress conditions, that resulted into greater stomata conductance and respiration rates. On the basis of these findings, we propose that P. oleracea employs multiple strategies to enhance its adaptation to high-temperature and high-humidity conditions.
Radiation and crop improvement

Energy Technology Data Exchange (ETDEWEB)

NONE

1960-09-15

The present state of the research was reviewed and its results analyzed at an international scientific Symposium on the Effects of Ionizing Radiations on Seeds and their Significance for Crop Improvement held at Karlsruhe, Federal Republic of Germany, in 1960. The experts began a detailed examination of certain special aspects of the radiobiology of seeds. Some of the topics discussed related to the processes initiated in seeds as a result of irradiation. The influence of environmental factors, such as temperature, humidity and the presence or absence of oxygen, was also evaluated. Variations in the sensitivity to radiation were taken into consideration and ways of modifying the sensitivity were examined. Two sessions were devoted to a study of radiation- and chemically-induced chromosome breakage and reunion. The nature and mechanism of chromosome breakage and reunion area subject of basic importance in all radiobiological studies and naturally constituted one of the main topics of discussion at the Karlsruhe symposium. The symposium discussed the relevance of these basic scientific questions to crop improvement. Whether irradiation itself, without producing any hereditary changes, can stimulate crop yields is a matter of considerable interest. It has been found that in some cases the effect is stimulating, while in others it is inhibitive. A number of experiments were described and an attempt was made to deduce certain principles from the results obtained
Assessment of the Potential Impacts of Wheat Plant Traits across Environments by Combining Crop Modeling and Global Sensitivity Analysis

Science.gov (United States)

Casadebaig, Pierre; Zheng, Bangyou; Chapman, Scott; Huth, Neil; Faivre, Robert; Chenu, Karine

2016-01-01

A crop can be viewed as a complex system with outputs (e.g. yield) that are affected by inputs of genetic, physiology, pedo-climatic and management information. Application of numerical methods for model exploration assist in evaluating the major most influential inputs, providing the simulation model is a credible description of the biological system. A sensitivity analysis was used to assess the simulated impact on yield of a suite of traits involved in major processes of crop growth and development, and to evaluate how the simulated value of such traits varies across environments and in relation to other traits (which can be interpreted as a virtual change in genetic background). The study focused on wheat in Australia, with an emphasis on adaptation to low rainfall conditions. A large set of traits (90) was evaluated in a wide target population of environments (4 sites × 125 years), management practices (3 sowing dates × 3 nitrogen fertilization levels) and CO2 (2 levels). The Morris sensitivity analysis method was used to sample the parameter space and reduce computational requirements, while maintaining a realistic representation of the targeted trait × environment × management landscape (∼ 82 million individual simulations in total). The patterns of parameter × environment × management interactions were investigated for the most influential parameters, considering a potential genetic range of +/- 20% compared to a reference cultivar. Main (i.e. linear) and interaction (i.e. non-linear and interaction) sensitivity indices calculated for most of APSIM-Wheat parameters allowed the identification of 42 parameters substantially impacting yield in most target environments. Among these, a subset of parameters related to phenology, resource acquisition, resource use efficiency and biomass allocation were identified as potential candidates for crop (and model) improvement. PMID:26799483
Assessment of the Potential Impacts of Wheat Plant Traits across Environments by Combining Crop Modeling and Global Sensitivity Analysis.

Directory of Open Access Journals (Sweden)

Pierre Casadebaig

Full Text Available A crop can be viewed as a complex system with outputs (e.g. yield that are affected by inputs of genetic, physiology, pedo-climatic and management information. Application of numerical methods for model exploration assist in evaluating the major most influential inputs, providing the simulation model is a credible description of the biological system. A sensitivity analysis was used to assess the simulated impact on yield of a suite of traits involved in major processes of crop growth and development, and to evaluate how the simulated value of such traits varies across environments and in relation to other traits (which can be interpreted as a virtual change in genetic background. The study focused on wheat in Australia, with an emphasis on adaptation to low rainfall conditions. A large set of traits (90 was evaluated in a wide target population of environments (4 sites × 125 years, management practices (3 sowing dates × 3 nitrogen fertilization levels and CO2 (2 levels. The Morris sensitivity analysis method was used to sample the parameter space and reduce computational requirements, while maintaining a realistic representation of the targeted trait × environment × management landscape (∼ 82 million individual simulations in total. The patterns of parameter × environment × management interactions were investigated for the most influential parameters, considering a potential genetic range of +/- 20% compared to a reference cultivar. Main (i.e. linear and interaction (i.e. non-linear and interaction sensitivity indices calculated for most of APSIM-Wheat parameters allowed the identification of 42 parameters substantially impacting yield in most target environments. Among these, a subset of parameters related to phenology, resource acquisition, resource use efficiency and biomass allocation were identified as potential candidates for crop (and model improvement.
Assessment of the Potential Impacts of Wheat Plant Traits across Environments by Combining Crop Modeling and Global Sensitivity Analysis.

Science.gov (United States)

Casadebaig, Pierre; Zheng, Bangyou; Chapman, Scott; Huth, Neil; Faivre, Robert; Chenu, Karine

2016-01-01

A crop can be viewed as a complex system with outputs (e.g. yield) that are affected by inputs of genetic, physiology, pedo-climatic and management information. Application of numerical methods for model exploration assist in evaluating the major most influential inputs, providing the simulation model is a credible description of the biological system. A sensitivity analysis was used to assess the simulated impact on yield of a suite of traits involved in major processes of crop growth and development, and to evaluate how the simulated value of such traits varies across environments and in relation to other traits (which can be interpreted as a virtual change in genetic background). The study focused on wheat in Australia, with an emphasis on adaptation to low rainfall conditions. A large set of traits (90) was evaluated in a wide target population of environments (4 sites × 125 years), management practices (3 sowing dates × 3 nitrogen fertilization levels) and CO2 (2 levels). The Morris sensitivity analysis method was used to sample the parameter space and reduce computational requirements, while maintaining a realistic representation of the targeted trait × environment × management landscape (∼ 82 million individual simulations in total). The patterns of parameter × environment × management interactions were investigated for the most influential parameters, considering a potential genetic range of +/- 20% compared to a reference cultivar. Main (i.e. linear) and interaction (i.e. non-linear and interaction) sensitivity indices calculated for most of APSIM-Wheat parameters allowed the identification of 42 parameters substantially impacting yield in most target environments. Among these, a subset of parameters related to phenology, resource acquisition, resource use efficiency and biomass allocation were identified as potential candidates for crop (and model) improvement.
Room temperature humidity sensor based on polyaniline-tungsten disulfide composite

Science.gov (United States)

Manjunatha, S.; Chethan, B.; Ravikiran, Y. T.; Machappa, T.

2018-05-01

Polyaniline-tungsten disulfide (PANI-WS2) composite was synthesized using in situ polymerization technique by adding finely grinded powder of WS2 during the polymerization of aniline. Field emission scanning electron microscopy (FESEM) images showed the granular morphology with porous nature. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of carbon, nitrogen, chlorine of PANI, tungsten and sulfur elements of WS2. Humidity sensing property of the composite was investigated by plotting change in its resistance with different relative humidity environments ranging from 10 to 97% RH. Decrease in resistance of the composite was observed with increase in relative humidity. Maximum sensing response of the composite was found to be 88.46%. Response and recovery times of the composite at 97%RH were fair enough to fabricate a sensor based on it. Stability of the composite with respect to the humidity sensing behavior was observed to be unchanged even after two months.
Characteristics and influencing factors of crop coefficient for drip-irrigated cotton under plastic mulch conditions in arid environment

DEFF Research Database (Denmark)

Ai, Zhipin; Yang, Yonghui; Wang, Qinxue

2017-01-01

agronomy practice such as plastic mulching and drip irrigation in arid environments. This study calculated and analyzed Kc of a drip-irrigated and plastic-mulched cotton field in Aksu Oasis of the arid Tarim River Basin, China, and its relationships with several crop-, soil- and management variables......-mulched condition already published, the Kc of mulched cotton for the entire growth season decreased by 16 to 39%. The largest reductions in Kc due to plastic mulch were found in the initial and developmental growth stage. Kc could be calculated by a third-degree polynomial model in relation to RGD, which...... significantly increased Kc, i.e., 29% on average, partly due to arid advection. This study provided up-to-date and detailed information on cotton crop coefficient under plastic mulching and drip irrigation conditions in arid environment, and it is useful for improved management of agricultural water resources....
Studies on the effects of application of different foliar fertilizer materials, crop residue and inter cropping on Banana plants

Energy Technology Data Exchange (ETDEWEB)

Hassan, Yusuf Munim [Faculty of Agriculture, University of Khartoum, Khartoum (Sudan)

1997-12-31

Five separate experiments were conducted at university of Khartoum demonstration farm during 1993 to 1995 under both orchard and nursery conditions to evaluate the effect of foliar application of different fertilizers, use of crop residue and intercropping on banana (dwarf cavendish). In the first experiment, the effects of foliar application of different concentrations of potassium solution (38%) were studied. The results indicated that application of all concentrations resulted in greater increases in overall growth parameters, higher leaf-N, P, K, Ca, Mg, Mn, Fe, Zn and Cu contents, higher values of yield and yield components , finger length of both plant crop and the first ratoon crop and reduction of time from planting to flowering and from flowering to harvesting of both plant crop and the first crop compared to the control. In the second experiment, the effects of three different foliar fertilizers, namely, compound cryst, fetrilon comb-2 and x-garden were investigated. The results revealed that all fertilizers gave greater values of all growth parameters, higher leaf-N, P, K, Ca, Mg, Mn, Fe, Zn and Cu contents, higher values of yield and yield components , finger length of both plant crop and the first ratoon crop and reduction of time from planting to flowering and from flowering to harvesting of both plant crop and the first crop compared to the control. In the third experiment, the effect of four different fertilizer materials containing different combinations of NPK on growth parameters and nutrient elements contents of leaves of banana suckers grown under nursery conditions was evaluated. The results revealed that all fertilizer materials gave greater increases of growth parameters over the control as well as higher leaf-N, P, K, Ca, Mg, Mn, Fe, Zn and Cu contents. In the fourth experiment, the effect of different concentrations of N{sub 19}, P{sub 19}, K{sub 19} fertilizers on growth characteristics and nutrient elements contents of leaves of banana
Estimating irrigation water use in the humid eastern United States

Science.gov (United States)

Levin, Sara B.; Zarriello, Phillip J.

2013-01-01

Accurate accounting of irrigation water use is an important part of the U.S. Geological Survey National Water-Use Information Program and the WaterSMART initiative to help maintain sustainable water resources in the Nation. Irrigation water use in the humid eastern United States is not well characterized because of inadequate reporting and wide variability associated with climate, soils, crops, and farming practices. To better understand irrigation water use in the eastern United States, two types of predictive models were developed and compared by using metered irrigation water-use data for corn, cotton, peanut, and soybean crops in Georgia and turf farms in Rhode Island. Reliable metered irrigation data were limited to these areas. The first predictive model that was developed uses logistic regression to predict the occurrence of irrigation on the basis of antecedent climate conditions. Logistic regression equations were developed for corn, cotton, peanut, and soybean crops by using weekly irrigation water-use data from 36 metered sites in Georgia in 2009 and 2010 and turf farms in Rhode Island from 2000 to 2004. For the weeks when irrigation was predicted to take place, the irrigation water-use volume was estimated by multiplying the average metered irrigation application rate by the irrigated acreage for a given crop. The second predictive model that was developed is a crop-water-demand model that uses a daily soil water balance to estimate the water needs of a crop on a given day based on climate, soil, and plant properties. Crop-water-demand models were developed independently of reported irrigation water-use practices and relied on knowledge of plant properties that are available in the literature. Both modeling approaches require accurate accounting of irrigated area and crop type to estimate total irrigation water use. Water-use estimates from both modeling methods were compared to the metered irrigation data from Rhode Island and Georgia that were used to
Water Use and Quality Footprints of Biofuel Crops in Florida

Science.gov (United States)

Shukla, S.; Hendricks, G.; Helsel, Z.; Knowles, J.

2013-12-01

The use of biofuel crops for future energy needs will require considerable amounts of water inputs. Favorable growing conditions for large scale biofuel production exist in the sub-tropical environment of South Florida. However, large-scale land use change associated with biofuel crops is likely to affect the quantity and quality of water within the region. South Florida's surface and ground water resources are already stressed by current allocations. Limited data exists to allocate water for growing the energy crops as well as evaluate the accompanying hydrologic and water quality impacts of large-scale land use changes. A three-year study was conducted to evaluate the water supply and quality impacts of three energy crops: sugarcane, switchgrass, and sweet sorghum (with a winter crop). Six lysimeters were used to collect the data needed to quantify crop evapotranspiration (ETc), and nitrogen (N) and phosphorus (P) levels in groundwater and discharge (drainage and runoff). Each lysimeter (4.85 x 3.65 x 1.35 m) was equipped to measure water input, output, and storage. The irrigation, runoff, and drainage volumes were measured using flow meters. Groundwater samples were collected bi-weekly and drainage/runoff sampling was event based; samples were analyzed for nitrogen (N) and phosphorous (P) species. Data collected over the three years revealed that the average annual ETc was highest for sugarcane (1464 mm) followed by switchgrass and sweet sorghum. Sweet sorghum had the highest total N (TN) concentration (7.6 mg/L) in groundwater and TN load (36 kg/ha) in discharge. However, sweet sorghum had the lowest total P (TP) concentration (1.2 mg/L) in groundwater and TP load (9 kg/ha) in discharge. Water use footprint for ethanol (liter of water used per liter of ethanol produced) was lowest for sugarcane and highest for switchgrass. Switchgrass had the highest P-load footprint for ethanol. No differences were observed for the TN load footprint for ethanol. This is the
Genotype-environment interaction of maternal influence characteristics in Nellore cattle bred in the Brazilian humid tropical regions by reaction norm

Directory of Open Access Journals (Sweden)

Jorge Luís Ferreira

2015-08-01

Full Text Available Reaction Norm (RN is the study of genotype-environment interaction (GxE that complies with alternative ways of genotypes within different environments. This study was carried out to verify GxE by a reaction norm model of weights at 120 (W120 and 210 (W210 days of age in Nellore cattle raised in the Humid Tropical Regions of Brazil. Environmental gradients were obtained by solutions of contemporary groups which were fitted as co-variables in the random regression model via reaction norms. Mean weight at 120 days of age was 127.97 kg, and environmental gradients ranged between -27 and +26 kg. Average was 185.60 kg at 210 days of age and gradients ranged from -54 to +55 kg. Scale changes in the breeding values and heritability estimates occurred along the gradients for the two weights; the genetic correlations between breeding value breeding values were also similar for both weights. These correlations were high between the close gradients, and low to even negative between extreme environments. Slopes representing the environmental sensitivity were high, with changes of scale and changes in classification of ten bulls with a great numbers of calves for the two traits. When regression slopes of the ten bulls with the highest breeding value breeding values were evaluated, these values were different in W120 from those in W210, perhaps due to the greater influence of maternal effect on W120. These results characterize the influence of GxE on the pre-weaning weights of animals in the humid tropical regions of Brazil. Due to this, it is possible to get greater precision on the predictions of the animals breeding values breeding value. A less biased selection and a greater genetic progress occurred.
Multiscale analysis of deforestation risk due to commodity crop expansion in sub-Saharan Africa and the role of non-industrial producers

Science.gov (United States)

Ordway, E.; Asner, G. P.; Naylor, R. L.; Nkongho, R.; Lambin, E.

2017-12-01

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crop production to sub-Saharan Africa (SSA). We assess the effects of domestic- and export-oriented agricultural expansion on deforestation in SSA in recent decades at the global, regional and local scales. Using Cameroon as a case-study, we explore the influence of emerging oil palm expansion on deforestation in greater depth. We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Cote d'Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ±17.9) and lowest proportions of potentially available cropland outside forest areas (1% ±0.9). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41,582 thousand ha. Based on remote sensing and field survey results, however, medium- and large-scale non-industrial producers are driving a substantial fraction of the oil palm expansion leading to deforestation in Cameroon. Additionally, unlike Southeast Asia, oil palm expansion in sub-Saharan Africa is associated primarily with domestic market demands. In contrast, cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1, yet only amounted to 0.9% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Findings highlight that, although most agricultural expansion was associated with domestic demand, there
Influence of reinforcement grade and matrix composition on corrosion resistance of cast aluminium matrix composites (A3xx.x/SiCp) in a humid environment

Energy Technology Data Exchange (ETDEWEB)

Pardo, A.; Viejo, F.; Carboneras, M. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain); Lopez, M.D. [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, 28931, Mostoles, Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain)

2003-05-01

A study of the influence of the silicon carbide (SiC{sub p}) proportion and the matrix concentration of four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) exposed to high relative humid environment was carried out under simulation in a climatic chamber. The matrix of A360/SiC/xxp composites was virtually free of copper while the A380/SiC/xxp matrix contained 3.13-3.45wt% Cu and 1.39-1.44wt% Ni. The kinetics of the corrosion process was studied on the basis of gravimetric tests. The nature of corrosion products was analysed by Scanning Electron Microscopy (SEM) and Low Angle X-Ray Diffraction (XRD) before and after accelerated testing to determine the influence of microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion damage to Al/SiCp composites was low at 80% Relative Humidity (RH) and increased with temperature, SiCp proportion, relative humidity and Cu matrix concentration. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Eine Studie zum Einfluss des Siliziumkarbidanteils (SiCp) und der Zusammensetzung des Grundwerkstoffs von vier Aluminiummatrixverbundwerkstoffen (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p), die in Umgebungen mit relativ hoher Feuchtigkeit ausgelagert waren, wurde unter simulierten Bedingungen in einer Klimakammer durchgefuehrt. Die Matrix des A360/SiC/xxp-Verbundwerkstoffs war praktisch Kupfer-frei waehrend die A380/SiC/xxp Matrix 3,13-3,45 Gew.-% Cu und 1,39-1,44 Gew.-% Ni enthielt. Die Kinetik des Korrosionsprozesses wurde auf der Basis von gravimetrischen Messungen studiert. Die Beschaffenheit der Korrosionsprodukte wurde mittelt REM-Untersuchungen und
Sustainable use of Brackish water for crop production

International Nuclear Information System (INIS)

Chaudhry, M.R.; Iqbal, M.; Subhani, K.M.

2005-01-01

The good quality surface-water is not sufficient to meet the crop water requirement for potential crop production. To augment the inadequate supplies of good quality water the only alternative is the use of poor quality , ground water. To explore sustainable use of brackish water a study was conducted in Fordwah Eastern Sadiqia South, Bahawalnagar, Punjab during the year 1998-99 to 2000-2001 with the objective to evaluate the impact of different irrigation treatments on physical and chemical properties of soil and crops yield. The experiment was conducted on farmer's field with his collaboration. The initial soil pH was about 8.0 while ECe and SAR ranged between 2.0 to 4.1 dS m/sup -/1 and 7.1 to 15.1 (mmol/sub c/ L/sup -1/)1/2, respectively with sandy loam texture. The brackish water used for irrigation had ECiw, SAR and RSC between 5.6 to 6.7 dS m/sup -/1, 15.1 to 16.4 (mmolc L/sup -1/sup 1/2/ and 1.52 to 1.64 (mmol/sub c/ L/sup -1/.The crops tested were wheat during Rabi and cotton during Kharif season. The treatments tested were: irrigation with canal water (T/sub 1/), canal water during Rabi and drainage water during Kharif (T/sub 2/), drainage water for two years and canal water for one season(T/sub 3/); and drainage water for three years + application of gypsum at the rate of 25% of CWR and thereafter canal water for one season(T 4). Fertilizers were applied at the rate of 120-60-50 N, P/sub 2/O/sub 5/ and K20 kg ha/sup -1/, respectively in the form of urea, diammonium phosphate and sulfate of potash. Crops irrigated with drainage water visualized yield reduction depending upon the share of drainage water in the irrigation delta. Application of gypsum provided reasonable check against salinity build-up with brackish water irrigation besides a nominal boost of 3 and 5% in yield of wheat and cotton, respectively over comparable treatment of year-round brackish water irrigation lacking gypsum application. Drainage water in alternate arrangement of seasonal
Influence of fine water droplets to temperature and humidity

Science.gov (United States)

Hafidzal, M. H. M.; Hamzah, A.; Manaf, M. Z. A.; Saadun, M. N. A.; Zakaria, M. S.; Roslizar, A.; Jumaidin, R.

2015-05-01

Excessively dry air can cause dry skin, dry eyes and exacerbation of medical conditions. Therefore, many researches have been done in order to increase humidity in our environment. One of the ways is by using water droplets. Nowadays, it is well known in market stand fan equipped with water mister in order to increase the humidity of certain area. In this study, the same concept is applied to the ceiling fan. This study uses a model that combines a humidifier which functions as cooler, ceiling fan and scaled down model of house. The objective of this study is to analyze the influence of ceiling fan humidifier to the temperature and humidity in a house. The mechanism of this small model uses batteries as the power source, connected to the fan and the humidifier. The small water tank's function is to store and supply water to the humidifier. The humidifier is used to cool the room by changing water phase to fine water droplets. Fine water droplets are created from mechanism of the humidifier, which is by increasing the kinetic energy of water molecule using high frequency vibration that overcome the holding force between water molecules. Thus, the molecule of water will change to state of gas or mist. The fan is used to spread out the mist of water to surrounding of the room in order to enhance the humidity. Thermocouple and humidity meter are used to measure temperature and humidity in some period of times. The result shows that humidity increases and temperature decreases with time. This application of water droplet can be applied in the vehicles and engine in order to decrease the temperature.

Preparation of high critical temperature YBa{sub 2}Cu{sub 3}O{sub 7} superconducting coatings by thermal spray; Elaboration par projection a chaud de revetements supraconducteurs a haute temperature critique de type YBa{sub 2}Cu{sub 3}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Lacombe, Jacques

1991-09-20

The objective of this research thesis is the elaboration of YBa{sub 2}Cu{sub 3}O{sub 7} superconducting coatings by thermal spray. These coatings must have a high adherence, a high cohesion, and the best possible electrical characteristics. The author first briefly presents physical-chemical characteristics of this ceramic, and proposes a bibliographical synthesis on thick coatings prepared by thermal spray. In the next parts, he studies and describes conditions of elaboration of poly-granular coatings of YBa{sub 2}Cu{sub 3}O{sub 7}, and their structural and electric characteristics [French] Des revetements epais de YBa{sub 2}Cu{sub 3}O{sub 7} ont ete elabores par projection a chaud sur des substrats d'acier inoxydable revetus d'une sous-couche de Ni-Cr-Al-Y. Les principales etapes du processus de fabrication sont les suivantes: - preparation de la poudre par voie humide selon un procede mis au point au C.E.R.E.M., - realisation des revetements epais par projection a chaud de cette poudre selon trois differentes techniques: projection plasma atmospherique, projection plasma sous pression reduite, projection flamme oxyacetylenique. - traitement thermique en deux etapes des revetements pour recristalliser la phase YBa{sub 2}Cu{sub 3}O{sub 7} et la reoxygener (traitement thermique dans un four sous oxygene). Les depots elabores selon cette voie sont adherents et homogenes a la fois en composition et en morphologie. La phase supraconductrice YBa{sub 2}Cu{sub 3}O{sub 7} determinee par diffraction de rayons X est bien cristallisee; elle se presente sous forme de plaquettes d'environ 10 μm de long et 1 μm d'epaisseur sans orientation preferentielle. Les revetements realises par projection plasma atmospherique presentent les meilleures caracteristiques electriques: Tc(R=0) = 90.5K; ΔTc = 1K; ρ (300 K) = 0.7 - 0.8 mΩ.cm; Jc(77 K,0 T) = 1000 A/cm{sup 2}. Les proprietes d'ecrantage magnetique ont ete comparees a celles de materiaux utilises pour le blindage magnetique
N2O emissions from humid tropical agricultural soils: effects of soil moisture, texture and nitrogen availability

Science.gov (United States)

A.M. Weitza; E. Linderb; S. Frolkingc; P.M. Crillc; M. Keller

2001-01-01

We studied soil moisture dynamics and nitrous oxide (N2O) Â¯uxes from agricultural soils in the humid tropics of Costa Rica. Using a splitplot design on two soils (clay, loam) we compared two crop types (annual, perennial) each unfertilized and fertilized. Both soils are of andic origin. Their properties include relatively low bulk density and high organic matter...
Diversity in crop residue management across an intensification gradient in southern Africa

NARCIS (Netherlands)

Rusinamhodzi, Leonard; Corbeels, Marc; Giller, Ken E.

2016-01-01

Crop residues are important for livestock feed and nutrient cycling among many other functions on smallholder farming systems of sub-Saharan Africa. The objective of this study was to assess differences in resource endowment, crop productivity and crop residue management in selected sites in
Hydrological drought and wildfire in the humid tropics

NARCIS (Netherlands)

Taufik, Muh

2017-01-01

Drought is a recurrent hazard, which has happened throughout human history, and it is anticipated to become more severe in multiple regions across the world. Drought occurs in all climate regimes from humid to dry and from hot to cold. Drought is often viewed through its impact on environment and
A variational master equation approach to quantum dynamics with off-diagonal coupling in a sub-Ohmic environment

Energy Technology Data Exchange (ETDEWEB)

Sun, Ke-Wei [School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Fujihashi, Yuta; Ishizaki, Akihito [Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki 444-8585 (Japan); Zhao, Yang, E-mail: YZhao@ntu.edu.sg [Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

2016-05-28

A master equation approach based on an optimized polaron transformation is adopted for dynamics simulation with simultaneous diagonal and off-diagonal spin-boson coupling. Two types of bath spectral density functions are considered, the Ohmic and the sub-Ohmic. The off-diagonal coupling leads asymptotically to a thermal equilibrium with a nonzero population difference P{sub z}(t → ∞) ≠ 0, which implies localization of the system, and it also plays a role in restraining coherent dynamics for the sub-Ohmic case. Since the new method can extend to the stronger coupling regime, we can investigate the coherent-incoherent transition in the sub-Ohmic environment. Relevant phase diagrams are obtained for different temperatures. It is found that the sub-Ohmic environment allows coherent dynamics at a higher temperature than the Ohmic environment.
Straw and energy crops- analysis of economy, energy and environment

International Nuclear Information System (INIS)

Parsby, M.

1996-01-01

The purpose of the biomass agreement of 14 June 1993 was to increase the use of biomass fuels in the Danish power plants to 1.2 million tons straw and 200 000 wood chips. Contribution from straw combustion should reach 25 PJ in year 2000. However biomass cultivation can endanger the governmental policy of pesticide and nitrogen reduction in agriculture. In the worst harvest years straw quantity can be reduced to 70 % of the normal level, while in good years there would occur a 3-4 fold excess of straw. Supply depends in a decisive degree on the offered price as the indirect cost can vary much (wet straw, delayed sawing, lost fertilizer value etc.). Potential for energy crops can be based on ca 300 000 ha present fallow agricultural areas. Cost is higher than that for straw, the most probable plants are elephant grass, willow, rape, sugar beets, winter cereals. Cost is lower for perennial plants, but at least 10-12 years are necessary for such crops to become profitable. Generally the biofuel crops are more expensive than crops for immediate combustion. Expenses for energy crops will decrease with time per ton dry matter, but ground rent for soils previously fallow has to be taken into account. A reduced nitrogen fertilization will reduce the economic profits quite essentially due to smaller harvests. Pesticide consumption will not have to grow as straw and elephant grass do not require any larger quantities (unless very large areas of one crop are cultivated).(EG) 92 refs
Transient peat properties in two pond-peatland complexes in the sub-humid Western Boreal Plain, Canada

Directory of Open Access Journals (Sweden)

R.M. Petrone

2008-03-01

Full Text Available In the Canadian Western Boreal Plain (WBP, wetlands (ponds and peatlands comprise up to 50% of the landscape and represent unique habitat where summer precipitation is often outpaced by evapotranspiration and hillslope groundwater position does not follow topography. In this sub-humid location, groundwater fluxes and stores in riparian peatlands influence pond water levels and root zone moisture sources for forested uplands. To accurately describe the transport and retention of water in peat, it is important to consider peat subsidence. This paper quantifies the amount and effect of seasonal subsidence in a riparian peatland in the Utikuma Lake region in north-central Alberta, Canada. Results demonstrate that the deep and poorly decomposed peat deposits are resistant to compression, and that thick (and persistent ground frost hinders pore collapse (shrinkage above the water table until late summer when the ground has thawed. Even then, subsidence is still limited to the top 50 cm and is not closely related to changes in peatland water table or pond water level. Thus the water balance of these ponds and riparian areas appears to be less sensitive to peat volume changes than it is to the persistence of a substantial frost layer well into the snow-free period.
Response of vegetation to carbon dioxide - sorghum at elevated levels of CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Burnett, R.B.; Chaudhuri, U.N.; Kanemasu, E.T.; Kirkham, M.B.

1985-12-31

Enhancement of plant growth is an important effect of the rising concentration of atmospheric CO{sub 2}. Crops vary in response to elevated CO{sub 2}. Growth often appears greater in C{sub 3} plants than in C{sub 4} plants. But relatively little work has been done with C{sub 4} plants, and most of it has been with corn. The few existing C{sub 4} data conflict. Some studies indicate that the yield of C{sub 4} plants at elevated CO{sub 2} is about one-fourth that of C{sub 3} crops, but other studies show that C{sub 4} plants with increased CO{sub 2} yield at a rate the average for all crops.
Water use efficiency in potatoes crop using nuclear techniques in Tumbaco - Ecuador

International Nuclear Information System (INIS)

Calvache, Marcelo; Ontaneda, Milton; Flor Jorge.

1986-01-01

The optimum water layer for potatoes (Solanum tuberosum L.) was computed by the balance of mass method. This project was carried out in a Typic Ustropepts, Silty-Loam Soil at 'La Tola' Experimental Field. Soil humidity was determined through the neutron probe. Irrigation efficiency for the first application layer, - layer 3- (30 days old crop), was 17%. It was increased to 34% at the age of 100 days. Layer 2 was increased to 25% and layer 1 to 20%. By this time the crop was developed. Crop water consumptive usage at layer 3 was 476.4 mm; 355.7 mm in layer 2; 390.5 mm for layer 1 and 269.3 mm in layer 0. Yield production was of the 29. 24.; 18.4 and 15. Kg/ha respectively. It is concluded that the timely application of water to potato crops is very important
Application of nano-structured conducting polymers to humidity sensing

Science.gov (United States)

Park, Pilyeon

-term stability. PANI nanowires showed almost linear degradation with continuous use, while nano-columned PEDOT was stable over extended periods of time. The PANI nanowires were more reactive to the environment compared to the nano-columned PEDOT films. The only disadvantage of the nano-columned PEDOT sensor structure is that it loses its durability when it is directly exposed to liquid water or highly saturated humidity for long periods of time. A surface treatment of PEDOT was developed that enhanced its durability against water without degrading its sensor performance. Nano-columned PEDOT films look promising for breath sensors for medical usage because they have sub-second response times and are relatively chemically and physically stable.
Crop-water-environment models; selected papers to the workshop organized by the ICID Working Group on `Sustainable Crops and Water Use' at the occasion of the 16th Congress of the International Commission on Irrigation and Drainage at Cairo, Egypt

NARCIS (Netherlands)

Ragab, R.; El-Din El-Quosy, D.; Broek, van den B.J.; Pereira, L.S.

1996-01-01

The main aim of this workshop was to bring individuals and organizations together who contribute to the development and upgrading of crop-water-environment models. Twenty-four model papers were presented in three sessions: pesticides and nitrates, salinity, and crop water balance. Each presentation
Sensors based on mesoporous SnO{sub 2}-CuWO{sub 4} with high selective sensitivity to H{sub 2}S at low operating temperature

Energy Technology Data Exchange (ETDEWEB)

Stanoiu, Adelina; Simion, Cristian E. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Calderon-Moreno, Jose Maria; Osiceanu, Petre [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania); Florea, Mihaela [University of Bucharest, Faculty of Chemistry, Department of Organic Chemistry, Biochemistry and Catalysis, B-dul Regina Elisabeta 4-12, Bucharest (Romania); National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Teodorescu, Valentin S. [National Institute of Materials Physics, Atomistilor 405A, P.O. Box MG-7, 077125 Bucharest, Măgurele (Romania); Somacescu, Simona, E-mail: somacescu.simona@gmail.com [“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Surface Chemistry and Catalysis Laboratory, Spl. Independentei 202, 060021, Bucharest (Romania)

2017-06-05

Highlights: • Mesoporous SnO{sub 2}-CuWO{sub 4} obtained by an inexpensive synthesis route. • Powders characterization performed by a variety of complementary techniques. • SnO{sub 2}-CuWO{sub 4} layers with high selective sensitivity to H{sub 2}S. • Low operating temperature and relative humidity influences. - Abstract: Development of new sensitive materials by different synthesis routes in order to emphasize the sensing properties for hazardous H{sub 2}S detection is one of a nowadays challenge in the field of gas sensors. In this study we obtained mesoporous SnO{sub 2}-CuWO{sub 4} with selective sensitivity to H{sub 2}S by an inexpensive synthesis route with low environmental pollution level, using tripropylamine (TPA) as template and polyvinylpyrrolidone (PVP) as dispersant/stabilizer. In order to bring insights about the intrinsic properties, the powders were characterized by means of a variety of complementary techniques such as: X-Ray Diffraction, XRD; Transmission Electron Microscopy, TEM; High Resolution TEM, HRTEM; Raman Spectroscopy, RS; Porosity Analysis by N{sub 2} adsorption/desorption, BET; Scanning Electron Microscopy, SEM and X-ray Photoelectron Spectroscopy, XPS. The sensors were fabricated by powders deposition via screen-printing technique onto planar commercial Al{sub 2}O{sub 3} substrates. The sensor signals towards H{sub 2}S exposure at low operating temperature (100 °C) reaches values from 10{sup 5} (for SnWCu600) to 10{sup 6} (for SnWCu800) over the full range of concentrations (5–30 ppm). The recovery processes were induced by a short temperature trigger of 500 °C. The selective sensitivity was underlined with respect to the H{sub 2}S, relative to other potential pollutants and relative humidity (10–70% RH).
Repeatability and Reversibility of the Humidity Sensor Based on Photonic Crystal Fiber Interferometer

Science.gov (United States)

Hindal, S. S.; Taher, H. J.

2018-05-01

The RH sensor operation based on water vapor adsorption and desorption at the silica-air interface within the PCF. Sensor fabrication is simple; it includes splicing and cleaving the PCF with SMF only. PCF (LMA-10) with a certain length spliced to SMF (Corning-28). The PCFI spectrum exhibits good sensitivity to the variations of humidity. The PCFI response is observed for range of relative humidity values from (27% RH to 85% RH), the interference peaks position is found to be shifted to longer wavelength as the humidity increases. In this work, a 6cm length of PCFs is used, and it shows a sensitivity of (2.41pm / %RH), good repeatability, and reversible in nature. This humidity sensor has distinguished features as that the sensor does not require the use of a hygroscopic material, robust, compact size, immunity to electromagnetic interference, and it has potential applications for high humidity environments.
The impact of the cropping system management on soil erosion and fertility in Northeastern Romania

Energy Technology Data Exchange (ETDEWEB)

Jitareanu, G.; Ailincai, C.; Bucur, D.; Raus, L.; Filipov, F.; Cara, M.

2009-07-01

The mass of total carbon from Cambic Chernozem in the Moldavian Plain has recorded significant increases at higher than N{sub 1}40 P{sub 1}00 rates, in organo-mineral fertilization and in 4-year crop rotation, which included melioration plants of perennial grasses and legumes. In maize continuous cropping and wheat-maize rotation, very significant values of the carbon content were found only in the organo-mineral fertilization, in 4-year crop rotations + reserve field cultivated with perennial legumes and under N{sub 1}40 P{sub 1}00 fertilization. In comparison with 4-year crop rotations, in wheat-maize rotation with melioration plants (annual and perennial legumes and perennial grasses), the mean carbon content from soil has diminished from 18.6 to 16.4 C, g.Kg{sup -}1 and the content in mobile phosphorus decreased from 51.6 to 36.8 P-Al, mg.kg{sup -}1. The 40 year use of 3 and 4-year crop rotations has determined the increase in total carbon mass and mobile phosphorus from soil by 10% (1.7 C g-kg{sup -}1) and 31%, respectively (11.8 P-Al mg.kg{sup -}1), against maize continuous cropping. (Author) 6 refs.
40 CFR 265.276 - Food chain crops.

Science.gov (United States)

2010-07-01

... of crop and soil characteristics, sample selection criteria, sample size determination, analytical... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Food chain crops. 265.276 Section 265... FACILITIES Land Treatment § 265.276 Food chain crops. (a) An owner or operator of a hazardous waste land...
Damage of crops by environmental air pollution in Yokkaichi area

Energy Technology Data Exchange (ETDEWEB)

Taniyama, T; Sawanaka, K

1972-01-01

Crop damage from sulfur dioxide was evaluated in the Yokkaichi area in 1971 by measuring dry matter and seed production. The average concentration of SO/sub 2/ per hour was 0.034 ppM from April to November 1971. There were, however, some cases of monthly hourly averages greater than 0.4 ppM. In these situations damages to major crops was largely due to sulfurous and sulfuric acid mists. The damages to major crops included brown and red spots, apical and peripheral chlorosis, yellowing of leaves, belt-like yellowing of sheath, white or black discoloration of rice plants, nonfertilization of rice plants, apical blight and chlorosis of Welsh onion, partial yellowing and general withering of pine trees in summer (and some death), watering and chlorosis of leaves of brassica species, and yellowing and spot formation on Japanese radishes. Also noted was a decrease in tiller number of rice plants (17.4 in polluted vs. 19.4 in unpolluted areas). Some cases were found in which the sulfur content of SO/sub 2/-damaged crops was higher than that of undamaged crops.
Ultrahigh humidity sensitivity of graphene oxide.

Science.gov (United States)

Bi, Hengchang; Yin, Kuibo; Xie, Xiao; Ji, Jing; Wan, Shu; Sun, Litao; Terrones, Mauricio; Dresselhaus, Mildred S

2013-01-01

Humidity sensors have been extensively used in various fields, and numerous problems are encountered when using humidity sensors, including low sensitivity, long response and recovery times, and narrow humidity detection ranges. Using graphene oxide (G-O) films as humidity sensing materials, we fabricate here a microscale capacitive humidity sensor. Compared with conventional capacitive humidity sensors, the G-O based humidity sensor has a sensitivity of up to 37800% which is more than 10 times higher than that of the best one among conventional sensors at 15%-95% relative humidity. Moreover, our humidity sensor shows a fast response time (less than 1/4 of that of the conventional one) and recovery time (less than 1/2 of that of the conventional one). Therefore, G-O appears to be an ideal material for constructing humidity sensors with ultrahigh sensitivity for widespread applications.
Effect of vulcanization temperature and humidity on the properties of RTV silicone rubber

Science.gov (United States)

Wu, Xutao; Li, Xiuguang; Hao, Lu; Wen, Xishan; Lan, Lei; Yuan, Xiaoqing; Zhang, Qingping

2017-06-01

In order to study the difference in performance of room temperature vulcanized (RTV) silicone rubber in vulcanization environment with different temperature and humidity, static contact angle method, FTIR and TG is utilized to depict the properties of hydrophobicity, transfer of hydrophobicity, functional groups and thermal stability of RTV silicone rubber. It is found that different vulcanization conditions have effects on the characteristics of RTV silicone rubber, which shows that the hydrophobicity of RTV silicone rubber changes little with the vulcanization temperature but a slight increase with the vulcanization humidity. Temperature and humidity have obvious effects on the hydrophobicity transfer ability of RTV silicone rubber, which is better when vulcanization temperature is 5°C or vulcanization humidity is 95%. From the Fourier transform infrared spectroscopy, it can be concluded that humidity and temperature of vulcanization conditions have great effect on the functional groups of silicone rubber, and vulcanization conditions also have effect on thermal stability of RTV silicone rubber. When vulcanization temperature is 5°C or vulcanization humidity is 15% or 95%, the thermal stability of silicone rubber becomes worse.
40 CFR 264.276 - Food-chain crops.

Science.gov (United States)

2010-07-01

...) Describe the procedures used in conducting any tests, including the sample selection criteria, sample size... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Food-chain crops. 264.276 Section 264... Treatment § 264.276 Food-chain crops. The Regional Administrator may allow the growth of food-chain crops in...
Humidity Testing of PME and BME Ceramic Capacitors with Cracks

Science.gov (United States)

Teverovsky, Alexander A.; Herzberger, Jaemi

2014-01-01

Cracks in ceramic capacitors are one of the major causes of failures during operation of electronic systems. Humidity testing has been successfully used for many years to verify the absence of cracks and assure quality of military grade capacitors. Traditionally, only precious metal electrode (PME) capacitors were used in high reliability applications and the existing requirements for humidity testing were developed for this type of parts. With the advance of base metal electrode (BME) capacitors, there is a need for assessment of the applicability of the existing techniques for the new technology capacitors. In this work, variety of different PME and BME capacitors with introduced cracks were tested in humid environments at different voltages and temperatures. Analysis of the test results indicates differences in the behavior and failure mechanisms for BME and PME capacitors and the need for different testing conditions.

Agronomic, Energetic and Environmental Aspects of Biomass Energy Crops Suitable for Italian Environments

Directory of Open Access Journals (Sweden)

Salvatore L. Cosentino

2008-06-01

Full Text Available The review, after a short introduction on the tendencies of the European Community Policy on biomasses, describes the agronomic, energy potential and environmental aspects of biomass crops for energy in relation to the research activity carried out in Italy on this topic, differentiating crops on the basis of the main energy use: biodiesel and bioethanol (which refers to “first generation biofuel”, heat and electricity. Currently, many of the crops for potential energy purposes are food crops (wheat, barley, corn, rapeseed, soybean, sunflower, grain sorghum, sugar beet and their production may be used as biofuel source (bioethanol and biodiesel since their crop management aspects are well known and consequently they are immediately applicable. Other species that could be used, highly productive in biomass, such as herbaceous perennial crops (Arundo donax, Miscanthus spp., cardoon, annual crops (sweet sorghum, short rotation woody crops (SRF have been carefully considered in Italy, but they still exhibit critical aspects related to propagation technique, low-input response, harvest and storage technique, cultivars and mechanization. Crops for food, however, often have negative energetic indices and environmental impacts (carbon sequestration, Life Cycle Assessment, consequent to their low productivity. Conversely, crops which are more productive in biomass, show both a more favourable energy balance and environmental impact.
Agronomic, Energetic and Environmental Aspects of Biomass Energy Crops Suitable for Italian Environments

Directory of Open Access Journals (Sweden)

Giuseppina M. D’Agosta

2011-02-01

Full Text Available The review, after a short introduction on the tendencies of the European Community Policy on biomasses, describes the agronomic, energy potential and environmental aspects of biomass crops for energy in relation to the research activity carried out in Italy on this topic, differentiating crops on the basis of the main energy use: biodiesel and bioethanol (which refers to “first generation biofuel”, heat and electricity. Currently, many of the crops for potential energy purposes are food crops (wheat, barley, corn, rapeseed, soybean, sunflower, grain sorghum, sugar beet and their production may be used as biofuel source (bioethanol and biodiesel since their crop management aspects are well known and consequently they are immediately applicable. Other species that could be used, highly productive in biomass, such as herbaceous perennial crops (Arundo donax, Miscanthus spp., cardoon, annual crops (sweet sorghum, short rotation woody crops (SRF have been carefully considered in Italy, but they still exhibit critical aspects related to propagation technique, low-input response, harvest and storage technique, cultivars and mechanization. Crops for food, however, often have negative energetic indices and environmental impacts (carbon sequestration, Life Cycle Assessment, consequent to their low productivity. Conversely, crops which are more productive in biomass, show both a more favourable energy balance and environmental impact.
Carbon isotope discrimination as a selection tool for high water use efficiency and high crop yields

International Nuclear Information System (INIS)

Kumarasinghe, K.S.; Kirda, C.; Bowen, G.D.; Zapata, F.; Awonaike, K.O.; Holmgren, E.; Arslan, A.; De Bisbal, E.C.; Mohamed, A.R.A.G.; Montenegro, A.

1996-01-01

Results of back-up research conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in support of the FAO/IAEA Co-ordinated Research Programme on the Use of Isotope Studies on Increasing and Stabilizing Plant Productivity in Low Phosphate and Semi-arid and Sub-humid Soils of the Tropics and Sub-tropics, are presented here. Neutron probe measurements confirmed the earlier reports of a strong correlation of Δ with grain yield and water use efficiency of wheat. High soil gypsum content and soil salinity, a wide spread problem in soils of arid and semi-arid climatic zones, do not interfere with the association of Δ with crop yields, provided plants are grown in similar soil water status and soil fertility level. Results of a glasshouse experiment using selected cowpea genotypes showed that Δ values measured at flowering stage positively correlated with total dry matter production and percent N 2 derived from atmosphere (%Ndfa), contributing to an earlier report from the laboratory that it may be possible to use Δ values for screening of leguminous crops for high N 2 fixation potential. 13 C isotope discrimination in the leaves of Gliricidia sepium was measured to examine if the technique could be extended to studies with trees. Results of a glasshouse experiment with 18 provenances of Gliricidia sepium showed highly significant correlations of Δ with total dry matter production, water use efficiency and total N accumulated through biological nitrogen fixation. Although the correlation of Δ with water use efficiency and dry matter yield are relatively clear and better understood, the correlation with nitrogen fixation still needs a closer examination under different environmental conditions and with different species. While 13 C isotope discrimination may be a valuable tool for identifying annual crops with high water use efficiency and high yield potential, it may be more attractive for tree species considering the long growth periods taken for trees
The effect of Co-doping on the humidity sensing properties of ordered mesoporous TiO2

Science.gov (United States)

Li, Zhong; Haidry, Azhar Ali; Gao, Bin; Wang, Tao; Yao, ZhengJun

2017-08-01

Monitoring of humidity is of utmost importance as it is essential part of almost every process in our life. Many commercial humidity sensors based on metal oxide semiconductors are available in the market, but there is still need to synthesize low-cost, fast and highly sensitive humidity sensors with no interference from background environment. The aim of this work was to fabricate the ordered mesoporous un-doped and Co-doped TiO2 (0.1-5 mol% Co) and to analyze its humidity sensing properties at room temperatures. The ordered mesoporous powders with high specific surface area (SSA) were prepared by multicomponent self-assembly procedure and then spray-coated onto the sensor substrates with interdigitated gold electrodes. The sensors exhibited excellent stability and reproducible resistance change under various relative humidity percentages (9-90% RH) with negligible effect of background environment. For instance, the response to 90% RH at room temperature was about five orders of magnitude (∼1.39 × 105) and the response time (Tres) was ∼24 s. The reaction/recovery times of the sensors were compared with commercial humidity sensor to show that the reaction times in this work are not given by the surface reaction of water vapor on the sensor surfaces, rather these are mainly influenced by the experimental setup. The sensor response increased up to 3 mol% Co-contents and then decreased for 5 mol% Co-contents. Based on the experimental results, the surface reaction of humidity is discussed related to specific surface area, average grain size and cobalt contents to understand the humidity sensing mechanism.
Africa needs streamlined regulation to support the deployment of GM crops.

Science.gov (United States)

Atkinson, Howard J; Roderick, Hugh; Tripathi, Leena

2015-08-01

Future food security in sub-Saharan Africa (SSA) requires enhancement of its crop production. Transgenic crops with a poverty focus can enhance harvests and are available for staples such as cooking bananas and plantains. One constraint is optimisation of national biosafety processes to support rapid and safe uptake of such beneficial crops. Copyright © 2015 Elsevier Ltd. All rights reserved.
IEC Quality Assurance Task Group 5: UV, Temperature, and Humidity (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Miller, D.; Bath, J.; Kohl, M.; Shioda, T.

2014-03-01

Taskgroup 5 (TG5) is concerned with a comparative aging standard incorporating factors including ultraviolet radiation, temperature, and humidity. Separate experiments are being conducted in support of a test standard via the regional sub-groups in Asia, Europe, and the United States. The authors will describe the objectives and timeline for TG5 as well as providing an update on the experiments in progress.
Biofuels production for smallholder producers in the Greater Mekong Sub-region

Energy Technology Data Exchange (ETDEWEB)

Malik, Urooj S.; Ahmed, Mahfuz [Southeast Asia Department, Asian Development Bank, 6 ADB Avenue, Mandaluyong City 1550 (Philippines); Sombilla, Mercedita A. [Southeast Asian Center for Graduate Studies and Research in Agriculture (SEARCA), Consulting Services Department, 4031 College, Laguna (Philippines); Cueno, Sarah L. [Agricultural Economist and Regional Program Coordinator Greater Mekong Subregion Economic Cooperation Program Working Group on Agriculture, Southeast Asia Department, Asian Development Bank, 6 ADB Avenue, Mandaluyong City 1550 (Philippines)

2009-11-15

Looming concerns on rising food prices and food security has slowed down the impetus in biofuel production. The development of the sub-sector, however, remains an important agenda among developing countries like those of the Greater Mekong Sub-region (GMS) that have abundant labour and natural resources but have limited supply of fossil fuels which continues to serve as a constraint to economic growth. Five crops have been selected to be further developed and use for biofuel production in the GMS, namely sugarcane, cassava, oil palm, sweet sorghum and Jathropa curcas. The expanded use of sugarcane, cassava, and oil palm for biofuel production can cause problems in the food sector. The other two crops, sweet sorghum and J. curcas, are non-food crops but could still compete with the food crops in terms of resource use for production. In all cases, the GMS needs to formulate a sustainable strategy for the biofuel development that will not compete with the food sector but will rather help achieve energy security, promote rural development and protect the environment. Except for People's Republic of China (PRC) and Thailand that already have fairly developed biofuel sub-sector, the other GMS countries are either poised to start (Lao PDR and Cambodia) or ready to enhance existing initiatives on biofuel production (Myanmar and Vietnam), with support from their respective governments. Biofuel development in these countries has to be strongly integrated with smallholder producers in order to have an impact on improving livelihood. At this initial stage, the sub-sector does not need to compete on a price basis but should rather aim to put up small-scale biofuel processing plants in remote rural areas that can offer an alternative to high-priced diesel and kerosene for local electricity grids serving homes and small enterprises. The social and economic multiplier effects are expected to be high when farmers that produce the energy crops also produce the biofuels to
Biofuels production for smallholder producers in the Greater Mekong Sub-region

International Nuclear Information System (INIS)

Malik, Urooj S.; Ahmed, Mahfuz; Sombilla, Mercedita A.; Cueno, Sarah L.

2009-01-01

Looming concerns on rising food prices and food security has slowed down the impetus in biofuel production. The development of the sub-sector, however, remains an important agenda among developing countries like those of the Greater Mekong Sub-region (GMS) that have abundant labour and natural resources but have limited supply of fossil fuels which continues to serve as a constraint to economic growth. Five crops have been selected to be further developed and use for biofuel production in the GMS, namely sugarcane, cassava, oil palm, sweet sorghum and Jathropa curcas. The expanded use of sugarcane, cassava, and oil palm for biofuel production can cause problems in the food sector. The other two crops, sweet sorghum and J. curcas, are non-food crops but could still compete with the food crops in terms of resource use for production. In all cases, the GMS needs to formulate a sustainable strategy for the biofuel development that will not compete with the food sector but will rather help achieve energy security, promote rural development and protect the environment. Except for People's Republic of China (PRC) and Thailand that already have fairly developed biofuel sub-sector, the other GMS countries are either poised to start (Lao PDR and Cambodia) or ready to enhance existing initiatives on biofuel production (Myanmar and Vietnam), with support from their respective governments. Biofuel development in these countries has to be strongly integrated with smallholder producers in order to have an impact on improving livelihood. At this initial stage, the sub-sector does not need to compete on a price basis but should rather aim to put up small-scale biofuel processing plants in remote rural areas that can offer an alternative to high-priced diesel and kerosene for local electricity grids serving homes and small enterprises. The social and economic multiplier effects are expected to be high when farmers that produce the energy crops also produce the biofuels to generate
Interception of residual nitrate from a calcareous alluvial soil profile on the North China Plain by deep-rooted crops: A {sup 15}N tracer study

Energy Technology Data Exchange (ETDEWEB)

Ju, X.T. [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Agricultural Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Hai Dian District, Beijing 100094 (China)]. E-mail: juxt@cau.edu.cn; Gao, Q. [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Agricultural Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Hai Dian District, Beijing 100094 (China); College of Agricultural Resources and Environmental Sciences, Jilin Agricultural University, Changchun 130118 (China); Christie, P. [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Agricultural Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Hai Dian District, Beijing 100094 (China); Agricultural and Environmental Science Department, Queen' s University Belfast, Belfast BT9 5PX (United Kingdom); Zhang, F.S. [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Agricultural Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Hai Dian District, Beijing 100094 (China)

2007-03-15

{sup 15}N-labeled nitrate was injected into different depths of an alluvial calcareous soil profile on the North China Plain. Subsequent movement of NO{sub 3} {sup -}N and its recovery by deep-rooted maize (Zea mays L.) and shallow-rooted eggplant (Solanum melongena L.) were studied. Under conventional water and nutrient management the mean recoveries of {sup 15}N-labeled nitrate from K{sup 15}NO{sub 3} injected at depths 15, 45, and 75 cm were 22.4, 13.8, and 7.8% by maize and 7.9, 4.9, and 2.7% by eggplant. The recovery rate by maize at each soil depth was significantly higher than by eggplant. The deeper the injection of nitrate the smaller the distance of its downward movement and this corresponded with the movement of soil water during crop growth. Deeper rooting crops with high root length density and high water consumption may therefore be grown to utilize high concentrations of residual nitrate in the subsoil from previous intensive cropping and to protect the environment. - Deep-rooted crops have a greater capacity than shallow-rooted crops to intercept residual nitrate from the subsoil and restrict its movement down to the shallow groundw0010at.
Measuring relative humidity in the radioactive environment of the IRRAD proton facility

CERN Document Server

Paerg, Marten

2017-01-01

The aim of the project was to obtain information on relative humidity conditions at different locations in the IRRAD proton facility. Due to high radiation levels inside the facility, different sensors had to be qualified and dedicated electronics had to be built to transfer the data of the sensors over long wires to a less radioactive area, where it could be collected.
Induction of Male sterile mutants in vegetable crops

Energy Technology Data Exchange (ETDEWEB)

Nagata, Nobuhiko [Hokkaido National Agricultural Experiment Station, Sapporo (Japan)

1982-03-01

The cultivars of vegetable crops in Japan are almost all F/sub 1/ hybrid lines. These hybrid cultivars are superior in yield, quality and uniformity by heterosis, and play an important role in the protection of breeder's rights. Utilization of male sterile mutants has such advantages as the reduction of cost for F/sub 1/ production by saving labor, production of better seeds, that is, pollination without emasculation and avoidance of contamination caused by self pollination. Male sterility must be used for some species in which seed production is difficult because of tiny flowers and meager seed production by artificial crossing such as carrot and onion, and those in which pollination by bag or emasculation is expensive such as tomato, and sweet pepper. However, for vegetable crop breeeding, the induction and use of genetic male sterility are more difficult than for other crops, considering the economy and efficiency of research because the type of cultivars needed changes rapidly.
Induction of Male sterile mutants in vegetable crops

Energy Technology Data Exchange (ETDEWEB)

Nagata, Nobuhiko (Hokkaido National Agricultural Experiment Station, Sapporo (Japan))

1982-03-01

The cultivars of vegetable crops in Japan are almost all F/sub 1/ hybrid lines. These hybrid cultivars are superior in yield, quality and uniformity by heterosis, and play an important role in the protection of breeder's rights. Utilization of male sterile mutants has such advantages as the reduction of cost for F/sub 1/ production by saving labor, production of better seeds, that is, pollination without emasculation and avoidance of contamination caused by self pollination. Male sterility must be used for some species in which seed production is difficult because of tiny flowers and meager seed production by artificial crossing such as carrot and onion, and those in which pollination by bag or emasculation is expensive such as tomato, and sweet pepper. However, for vegetable crop breeeding, the induction and use of genetic male sterility are more difficult than for other crops, considering the economy and efficiency of research because the type of cultivars needed changes rapidly.
High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes.

Science.gov (United States)

Devleesschauwer, Brecht; Marvasi, Massimiliano; Giurcanu, Mihai C; Hochmuth, George J; Speybroeck, Niko; Havelaar, Arie H; Teplitski, Max

2017-09-01

Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood. Copyright © 2017 Elsevier Ltd. All rights reserved.
Induction of Viable but Nonculturable Salmonella in Exponentially Grown Cells by Exposure to a Low-Humidity Environment and Their Resuscitation by Catalase.

Science.gov (United States)

Morishige, Yuta; Koike, Atsushi; Tamura-Ueyama, Ai; Amano, Fumio

2017-02-01

Salmonella is a major cause of foodborne disease that sometimes occurs in massive outbreaks around the world. This pathogen is tolerant of low-humidity conditions. We previously described a method for induction of viable but nonculturable (VBNC) Salmonella enterica serovar Enteritidis by treatment with hydrogen peroxide (H 2 O 2 ) and subsequent resuscitation with 0.3 mM sodium pyruvate. Here, we report a new method for the induction of the VBNC state in Salmonella Enteritidis cells, one involving dehydration. Exposure of Salmonella Enteritidis cells to dehydration stress under poor nutritional conditions (0.9% [wt/vol] NaCl) and 10 to 20% relative humidity at room temperature decreased the presence of culturable population to 0.0067%, but respiratory and glucose uptake active populations were maintained at 0.46 and 1.12%, respectively, meaning that approximately 1% may have entered the VBNC state. Furthermore, these VBNC cells could be resuscitated to acquire culturability by incubation with catalase in M9 minimal medium without glucose in a manner dependent on the dose of catalase but not sodium pyruvate. These results suggest that a low-humidity environment could cause Salmonella Enteritidis cells to enter the VBNC state and the cells could then be resuscitated for growth by treatment with catalase, suggesting a potential risk of Salmonella Enteritidis to survive in low water activity foods in the VBNC state and to start regrowth for foodborne illness.
Discomfort due to skin humidity with different fabric textures and materials

DEFF Research Database (Denmark)

Toftum, Jørn; Rasmussen, Leif Winsnes; Mackeprang, Jørgen

2000-01-01

This study investigated the possible effects of material and texture of the inner clothing layer on human comfort. A highly hygroscopic material (cotton) and a material of low hygroscopicity (polyester) were tested. Also, it was tested whether fabric texture (knitted/woven) influenced the perceived...... due to humid skin or clothing for persons engaged in office work, wearing woven or knitted inner layers made of polyester or cotton. The model allows upper limits for air humidity to be determined for indoor environments. In the comfort zone of temperatures, the model predicts only a moderate...
Edaphic factors controlling summer (rainy season) greenhouse gas emissions (CO{sub 2} and CH{sub 4}) from semiarid mangrove soils (NE-Brazil)

Energy Technology Data Exchange (ETDEWEB)

Nóbrega, Gabriel N. [Departamento de Ciência do Solo, Escola Superior de Agricultura Luiz de Queiroz, ESALQ/USP, Av.Pádua Dias 11, Piracicaba, São Paulo 13.418-260 (Brazil); Ferreira, Tiago O., E-mail: toferreira@usp.br [Departamento de Ciência do Solo, Escola Superior de Agricultura Luiz de Queiroz, ESALQ/USP, Av.Pádua Dias 11, Piracicaba, São Paulo 13.418-260 (Brazil); Siqueira Neto, M. [Laboratório de Biogeoquímica Ambiental, Centro de Energia Nuclear na Agricultura, CENA/USP, Av. Centenário 303, Piracicaba, São Paulo 13.400-970 (Brazil); Queiroz, Hermano M.; Artur, Adriana G. [Departamento de Ciências do Solo, Universidade Federal do Ceará, UFC, Av. Mister Hull 2977, Campus do Pici, Fortaleza, Ceará 60.440-554 (Brazil); Mendonça, Eduardo De S. [Departamento de Produção Vegetal, Universidade Federal do Espírito Santo, UFES, Alto Universitário s/n, Alegre, Espírito Santo 29.500-000 (Brazil); Silva, Ebenezer De O. [Empresa Brasileira de Pesquisa Agropecuária, Centro Nacional de Pesquisa de Agroindústria Tropical, Pós Colheita, Dra. Sara Mesquita Street, 2270, Planalto Pici, Fortaleza, Ceará 60.511-110 (Brazil); and others

2016-01-15

The soil attributes controlling the CO{sub 2}, and CH{sub 4} emissions were assessed in semiarid mangrove soils (NE-Brazil) under different anthropogenic activities. Soil samples were collected from different mangroves under different anthropogenic impacts, e.g., shrimp farming (Jaguaribe River); urban wastes (Cocó River) and a control site (Timonha River). The sites were characterized according to the sand content; physicochemical parameters (Eh and pH); total organic C; soil C stock (SCS) and equivalent SCS (SCS{sub EQV}); total P and N; dissolved organic C (DOC); and the degree of pyritization (DOP). The CO{sub 2} and CH{sub 4} fluxes from the soils were assessed using static closed chambers. Higher DOC and SCS and the lowest DOP promote greater CO{sub 2} emission. The CH{sub 4} flux was only observed at Jaguaribe which presented higher DOP, compared to that found in mangroves from humid tropical climates. Semiarid mangrove soils cannot be characterized as important greenhouse gas sources, compared to humid tropical mangroves. - Highlights: • GHG emission was associated with different soil characteristics. • Highest CO{sub 2} emissions were found in mangroves with larger dissolved C and lower DOP. • Less CH{sub 4} flux was due to low DOP in semiarid mangrove soils.
Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

International Nuclear Information System (INIS)

Hayashi, Kiyotada; Nagumo, Yoshifumi; Domoto, Akiko

2016-01-01

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.
Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Kiyotada, E-mail: hayashi@affrc.go.jp [Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan); Nagumo, Yoshifumi [Crop Research Center, Niigata Agricultural Research Institute, 857 Nagakura-machi, Nagaoka, Niigata 940-0826 (Japan); Domoto, Akiko [Mie Prefecture Agricultural Research Institute, 530 Kawakita-cho, Ureshino, Matsusaka, Mie 515-2316 (Japan)

2016-11-15

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.
Turbulent transport across an interface between dry and humid air in a stratified environment

Science.gov (United States)

Gallana, Luca; de Santi, Francesca; di Savino, Silvio; Iovieno, Michele; Ricchiardone, Renzo; Tordella, Daniela

2014-11-01

The transport of energy and water vapor across a thin layer which separates two decaying isotropic turbulent flows with different kinetic energy and humidity is considered. The interface is placed in a shearless stratified environment in temporal decay. This system reproduces a few aspects of small scale turbulent transport across a dry air/moist air interface in an atmospheric like context. In our incompressible DNS at Reλ = 250 , Boussinesq's approximation is used for momentum and energy transport while the vapor is modeled as a passive scalar (Kumar, Schumacher & Shaw 2014). We investigated different stratification levels with an initial Fr between 0.8 and 8 in presence of a kinetic energy ratio equal to 7. As the buoyancy term becomes of the same order of the inertial ones, a spatial redistribution of kinetic energy, dissipation and vapor concentration is observed. This eventually leads to the onset of a well of kinetic energy in the low energy side of the mixing layer which blocks the entrainment of dry air. Results are discussed and compared with laboratory and numerical experiments. A posteriori estimates of the eventual compression/expansion of fluid particles inside the interfacial mixing layer are given (Nance & Durran 1994).
Static flexural properties of hedgehog spines conditioned in coupled temperature and relative humidity environments.

Science.gov (United States)

Kennedy, Emily B; Hsiung, Bor-Kai; Swift, Nathan B; Tan, Kwek-Tze

2017-11-01

Hedgehogs are agile climbers, scaling trees and plants to heights exceeding 10m while foraging insects. Hedgehog spines (a.k.a. quills) provide fall protection by absorbing shock and could offer insights for the design of lightweight, material-efficient, impact-resistant structures. There has been some study of flexural properties of hedgehog spines, but an understanding of how this keratinous biological material is affected by various temperature and relative humidity treatments, or how spine color (multicolored vs. white) affects mechanics, is lacking. To bridge this gap in the literature, we use three-point bending to analyze the effect of temperature, humidity, spine color, and their interactions on flexural strength and modulus of hedgehog spines. We also compare specific strength and stiffness of hedgehog spines to conventional engineered materials. We find hedgehog spine flexural properties can be finely tuned by modifying environmental conditioning parameters. White spines tend to be stronger and stiffer than multicolored spines. Finally, for most temperature and humidity conditioning parameters, hedgehog spines are ounce for ounce stronger than 201 stainless steel rods of the same diameter but as pliable as styrene rods with a slightly larger diameter. This unique combination of strength and elasticity makes hedgehog spines exemplary shock absorbers, and a suitable reference model for biomimicry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Serum levels of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) in buffalo (Bubalus bubalis Lin.) raised in Amazon region; Niveis sericos de triiodotironina (T{sub 3}) e tiroxina (T{sub 4}) em bubalinos (Bubalus bubalis Lin.) criados na regiao Amazonica

Energy Technology Data Exchange (ETDEWEB)

Silva, A O.A. da

1991-08-01

Through the use of radioimmunoassay (RIA) it was determined blood serum concentration of triiodothyronine (T{sub 3}) and thyroxine (T{sub 4}) (n=78) for two different water buffalo racial groups. Blood serum was collected from young and adult animals belonging to two farms in Castanhal country, state of Para, Brazil, through the year of 1988. The serum levels of T{sub 3} and T{sub 4} were statistically correlated with climatic parameters, e.g., pluviometric precipitation, environmental temperature, humidity, light intensity variation and physiological factors such as age, breed and sex. It was identified two seasons during experiment, one season the rainfall period with high precipitation rates and the other one was considered as dry season, with low precipitation rates. The average rate of temperature and humidity have shown no significant statistic difference between the two seasons. On the other hand, it was found a significant relationship between luminosity and seasons, since when the luminosity decreases the pluviometric rates increases. (author). 51 refs, 15 figs, 15 tabs.
Engineering food crops to grow in harsh environments [v1; ref status: indexed, http://f1000r.es/5f1

Directory of Open Access Journals (Sweden)

Damar López-Arredondo

2015-09-01

Full Text Available Achieving sustainable agriculture and producing enough food for the increasing global population will require effective strategies to cope with harsh environments such as water and nutrient stress, high temperatures and compacted soils with high impedance that drastically reduce crop yield. Recent advances in the understanding of the molecular, cellular and epigenetic mechanisms that orchestrate plant responses to abiotic stress will serve as the platform to engineer improved crop plants with better designed root system architecture and optimized metabolism to enhance water and nutrients uptake and use efficiency and/or soil penetration. In this review we discuss such advances and how the generated knowledge could be used to integrate effective strategies to engineer crops by gene transfer or genome editing technologies.
The Economics of Genetically Modified Crops

OpenAIRE

Matin Qaim

2009-01-01

Genetically modified (GM) crops have been used commercially for more than 10 years. Available impact studies of insect-resistant and herbicide-tolerant crops show that these technologies are beneficial to farmers and consumers, producing large aggregate welfare gains as well as positive effects for the environment and human health. The advantages of future applications could even be much bigger. Given a conducive institutional framework, GM crops can contribute significantly to global food se...
Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

Directory of Open Access Journals (Sweden)

Tero Jalkanen

2015-01-01

Full Text Available A roll-to-roll compatible fabrication process of porous silicon (pSi based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.
Effects of ecological and conventional agricultural intensification practices on maize yields in sub-Saharan Africa under potential climate change

International Nuclear Information System (INIS)

Folberth, Christian; Yang, Hong; Gaiser, Thomas; Liu, Junguo; Wang, Xiuying; Williams, Jimmy; Schulin, Rainer

2014-01-01

Much of Africa is among the world’s regions with lowest yields in staple food crops, and climate change is expected to make it more difficult to catch up in crop production in particular in the long run. Various agronomic measures have been proposed for lifting agricultural production in Africa and to adapt it to climate change. Here, we present a projection of potential climate change impacts on maize yields under different intensification options in Sub-Saharan Africa (SSA) using an agronomic model, GIS-based EPIC (GEPIC). Fallow and nutrient management options taken into account are (a) conventional intensification with high mineral N supply and a bare fallow, (b) moderate mineral N supply and cowpea rotation, and (c) moderate mineral N supply and rotation with a fast growing N fixing tree Sesbania sesban. The simulations suggest that until the 2040s rotation with Sesbania will lead to an increase in yields due to increasing N supply besides improving water infiltration and soils’ water holding capacity. Intensive cultivation with a bare fallow or an herbaceous crop like cowpea in the rotation is predicted to result in lower yields and increased soil erosion during the same time span. However, yields are projected to decrease in all management scenarios towards the end of the century, should temperature increase beyond critical thresholds. The results suggest that the effect of eco-intensification as a sole means of adapting agriculture to climate change is limited in Sub-Saharan Africa. Highly adverse temperatures would rather have to be faced by improved heat tolerant cultivars, while strongly adverse decreases in precipitation would have to be faced by expanding irrigation where feasible. While the evaluation of changes in agro-environmental variables like soil organic carbon, erosion, and soil humidity hints that these are major factors influencing climate change resilience of the field crop, no direct relationship between these factors, crop yields
Effects of CO[sub 2] concentration on photosynthesis, transpiration and production of greenhouse fruit vegetable crops

Energy Technology Data Exchange (ETDEWEB)

Nederhoff, E.M.

1994-10-25

The effect of the CO[sub 2] concentration of the greenhouse air (C) in the range 200 to 1100 [mu]mol mol[sup -1] was investigated in tomato (Lycopersicon esculentum Mill.), cucumber (Cucumis sativus L.), sweet pepper (Capsicum annuum L.) and eggplant (Solanum melongena L.), grown in greenhouses. The effect of C on canopy net photosynthetic CO[sub 2] assimilation rate (or photosynthesis, P) was expressed by a set of regression equations, relating P to PAR, C and LAI. A rule of thumb ('CO[sub 2]-rule') was derived, approximating the relative increase of P caused by additional CO[sub 2] at a certain C. This CO[sub 2]-rule is: X = (1000/C)[sup 2] * 1.5 (X in % per 100 [mu]mol[sup -1], and C in [mu]mol mol[sup -1]). Two models for canopy photosynthesis were examined by comparing them with the experimental photosynthesis data. No 'midday depression' in P was observed. The effects of C on leaf conductance (g) and on rate of crop transpiration (E) were investigated. An increase of 100 I[mu]mol mol[sup -1] ' in C reduced g by about 3-4% in sweet pepper, tomato and cucumber and by about 11% in eggplant. The effect of C on E was analyzed by combining the regression equation for g with the Penman-Monteith equation for E. C had only a relatively small effect on E, owing to thermal and hydrological feedback effects. The decoupling of g and E was quantified. No time-dependent variation or 'midday depression' in E was observed, and no significant effect of C on average leaf temperature was established. In five experiments, the effect of C on growth and production and on specific features were analyzed; fruit production (dry weight) was most affected by C in sweet pepper; fresh weight fruit production per unit CO[sub 2] was highest in cucumber; fruit quality was not influenced by C. High C promoted the 'short leaves syndrome' in tomato and 'leaf tip chlorosis' in eggplant, probably related to calcium and boron translocation
nteraction of nutrient resource and crop diversity on resource use efficiency in different cropping systems

Directory of Open Access Journals (Sweden)

E azizi

2016-05-01

Full Text Available Introduction Conventional operations in fields, soil and water management are not efficient and loss of and damage to the environment are considerable (Lal, 2000. Crop diversity and understanding the complex interactions between environmental and socioeconomic factors are approaches to make better use of limited resources (Tengberg et al., 1998. The most diverse ecosystems have a higher production under environment stress conditions compared with ecosystems with low diversity due to the better efficiency in the use of water, radiation and nutrients (Hulugalle & al, 1986; Walker & Ogindo, 2003. Materials and Methods In order to investigate the effects of crop diversity and nutrient source on resource use efficiency, a split plot experiment was conducted based on complete randomized blocks with 3 replications at the Agricultural Research Station, the Ferdowsi University of Mashhad, Iran, during 2006 and 2007. The treatments included manure and chemical fertilizers as the main plots and intercropping of 3 soybean varieties (Williams, Sahar and Gorgan3, intercropping of 3 Millet species (common millet, foxtail millet and pearl millet, intercropping of millet, soybean and sesame (Sesamum indicum and intercropping of millet, sesame, fenugreek (Trigonella foenum-graecum and ajowan (Trachyspermum ammi as sub plots. Results and Discussion The results indicated that in the first year, intercropping of 3 Millet species and intercropping of millet, soybean and sesame showed the highest water use efficiency (WUE based on biological yield. In the second year, intercropping of 3 millet species showed the highest WUE based on biological yield. The highest concentrations of nitrogen, phosphorous and potassium in crop tissues were observed in intercropping of 3 soybean varieties and intercropping of millet, soybean and sesame. In the first year, intercropping of 3 soybean varieties showed the highest nutrient use efficiency (NUE. In the second year, intercropping
Assessment of FAO AquaCrop Model for Simulating Maize Growth and Productivity under Deficit Irrigation in a Tropical Environment

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Geneille E. Greaves

2016-11-01

Full Text Available Crop simulation models have a pivotal role to play in evaluating irrigation management strategies for improving agricultural water use. The objective of this study was to test and validate the AquaCrop model for maize under deficit irrigation management. Field observations from three experiments consisting of four treatments were used to evaluate model performance in simulating canopy cover (CC, biomass (B, yield (Y, crop evapotranspiration (ETc, and water use efficiency (WUE. Statistics for root mean square error, model efficiency (E, and index of agreement for B and CC suggest that the model prediction is good under non-stressed and moderate stress environments. Prediction of final B and Y under these conditions was acceptable, as indicated by the high coefficient of determination and deviations <10%. In severely stressed conditions, low E and deviations >11% for B and 9% for Y indicate a reduction in the model reliability. Simulated ETc and WUE deviation from observed values were within the range of 9.5% to 22.2% and 6.0% to 32.2%, respectively, suggesting that AquaCrop prediction of these variables is fair, becoming unsatisfactory as plant water stress intensifies. AquaCrop can be reliably used for evaluating the effectiveness of proposed irrigation management strategies for maize; however, the limitations should be kept in mind when interpreting the results in severely stressed conditions.
Spatiotemporal Dynamics of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) in Commercial Watermelon Crops.

Science.gov (United States)

Lima, Carlos H O; Sarmento, Renato A; Galdino, Tarcísio V S; Pereira, Poliana S; Silva, Joedna; Souza, Danival J; Dos Santos, Gil R; Costa, Thiago L; Picanço, Marcelo C

2018-04-16

Spatiotemporal dynamics studies of crop pests enable the determination of the colonization pattern and dispersion of these insects in the landscape. Geostatistics is an efficient tool for these studies: to determine the spatial distribution pattern of the pest in the crops and to make maps that represent this situation. Analysis of these maps across the development of plants can be used as a tool in precision agriculture programs. Watermelon, Citrullus lanatus (Thunb.) Matsum. and Nakai (Cucurbitales: Cucurbitaceae), is the second most consumed fruit in the world, and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important pests of this crop. Thus, the objective of this work was to determine the spatiotemporal distribution of B. tabaci in commercial watermelon crops using geostatistics. For 2 yr, we monitored adult whitefly densities in eight watermelon crops in a tropical climate region. The location of the samples and other crops in the landscape was georeferenced. Experimental data were submitted to geostatistical analysis. The colonization of B. tabaci had two patterns. In the first, the colonization started at the outermost parts of the crop. In the second, the insects occupied the whole area of the crop since the beginning of cultivation. The maximum distance between sites of watermelon crops in which spatial dependence of B. tabaci densities was observed was 19.69 m. The adult B. tabaci densities in the eight watermelon fields were positively correlated with rainfall and relative humidity, whereas wind speed negatively affected whiteflies population.
Modeling of an Aged Porous Silicon Humidity Sensor Using ANN Technique

Directory of Open Access Journals (Sweden)

Tarikul ISLAM

2006-10-01

Full Text Available Porous silicon (PS sensor based on capacitive technique used for measuring relative humidity has the advantages of low cost, ease of fabrication with controlled structure and CMOS compatibility. But the response of the sensor is nonlinear function of humidity and suffers from errors due to aging and stability. One adaptive linear (ADALINE ANN model has been developed to model the behavior of the sensor with a view to estimate these errors and compensate them. The response of the sensor is represented by third order polynomial basis function whose coefficients are determined by the ANN technique. The drift in sensor output due to aging of PS layer is also modeled by adapting the weights of the polynomial function. ANN based modeling is found to be more suitable than conventional physical modeling of PS humidity sensor in changing environment and drift due to aging. It helps online estimation of nonlinearity as well as monitoring of the fault of the PS humidity sensor using the coefficients of the model.
C and N accumulations in soil aggregates determine nitrous oxide emissions from cover crop treated rice paddy soils during fallow season

Energy Technology Data Exchange (ETDEWEB)

Pramanik, Prabhat, E-mail: prabhat2003@gmail.com; Haque, Md. Mozammel; Kim, Sang Yoon; Kim, Pil Joo, E-mail: pjkim@gnu.ac.kr

2014-08-15

Combination of leguminous and non-leguminous plant residues are preferably applied in rice paddy soils to increase the rate of organic matter mineralization and to improve plant growth. However, organic matter addition facilitates methane (CH{sub 4}) emission from rice paddy soil. Mineralization of organic nitrogen (N) increases NO{sub 3}–N concentrations in soil, which are precursors for the formation of nitrous oxide (N{sub 2}O). However, N{sub 2}O is a minor greenhouse gas emitted from submerged rice field and hence is not often considered during calculation of total global warming potential (GWP) during rice cultivation. The hypothesis of this study was that fluxes of N{sub 2}O emissions might be changed after removal of flooded water from rice field and the effect of cover crops on N{sub 2}O emissions in the fallow season might be interesting. However, the effects of N-rich plant residues on N{sub 2}O emission rates in the fallow season and its effect on annual GWP were not studied before. In this experiment, combination of barley (non-leguminous) and hairy vetch (leguminous) biomasses were applied at 9 Mg ha{sup −1} and 27 Mg ha{sup −1} rates in rice paddy soil. Cover crop application significantly increased CH{sub 4} emission flux while decreased N{sub 2}O emissions during rice cultivation. The lowest N{sub 2}O emission was observed in 27 Mg ha{sup −1} cover crop treated plots. Cover crop applications increased N contents in soil aggregates especially in smaller aggregates (< 250 μm), and that proportionately increased the N{sub 2}O emission potentials of these soil aggregates. Fluxes of N{sub 2}O emissions in the fallow season were influenced by the N{sub 2}O emission potentials of soil aggregates and followed opposite trends as those observed during rice cultivation. Therefore, it could be concluded that the doses of cover crop applications for rice cultivation should not be optimized considering only CH{sub 4}, but N{sub 2}O should also be
Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China

Science.gov (United States)

Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A.; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

2016-01-01

Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids. PMID:26829756
Farmer's perception of the effects of eartworms on soil fertility and crop performance in southern Cameroon

NARCIS (Netherlands)

Madong à Birang,; Hauser, S.; Amougou, D.L.

2003-01-01

The knowledge and perception of the effects of earthworms on soil fertility and crop growth was surveyed in a humid forest zone of southern Cameroon. A total of 215 farmers were interviewed in seven villages: two villages were near the capital Yaounde, severely deforested with a high land-use
Envirotyping for deciphering environmental impacts on crop plants.

Science.gov (United States)

Xu, Yunbi

2016-04-01

Global climate change imposes increasing impacts on our environments and crop production. To decipher environmental impacts on crop plants, the concept "envirotyping" is proposed, as a third "typing" technology, complementing with genotyping and phenotyping. Environmental factors can be collected through multiple environmental trials, geographic and soil information systems, measurement of soil and canopy properties, and evaluation of companion organisms. Envirotyping contributes to crop modeling and phenotype prediction through its functional components, including genotype-by-environment interaction (GEI), genes responsive to environmental signals, biotic and abiotic stresses, and integrative phenotyping. Envirotyping, driven by information and support systems, has a wide range of applications, including environmental characterization, GEI analysis, phenotype prediction, near-iso-environment construction, agronomic genomics, precision agriculture and breeding, and development of a four-dimensional profile of crop science involving genotype (G), phenotype (P), envirotype (E) and time (T) (developmental stage). In the future, envirotyping needs to zoom into specific experimental plots and individual plants, along with the development of high-throughput and precision envirotyping platforms, to integrate genotypic, phenotypic and envirotypic information for establishing a high-efficient precision breeding and sustainable crop production system based on deciphered environmental impacts.
Expression of allelopathy in the soil environment: Soil concentration and activity of benzoxazinoid compounds released by rye cover crop residue

Science.gov (United States)

The activity of allelopathic compounds is often reduced in the soil environment where processes involving release from donor plant material, soil adsorption and degradation, and uptake by receptor plants naturally result in complex interactions. Rye (Secale cereale L.) cover crops are known to supp...
Ethics and Transgenic Crops: a Review

OpenAIRE

Robinson, Jonathan

1999-01-01

This article represents a review of some of the ethical dilemmas that have arisen as a result of the development and deployment of transgenic crop plants. The potential for transgenic crops to alleviate human hunger and the possible effects on human health are discussed. Risks and benefits to the environment resulting from genetic engineering of crops for resistance to biotic and abiotic stresses are considered, in addition to effects on biodiversity. The socio-economic impacts and distributi...
Graphene based humidity-insensitive films

KAUST Repository

Tai, Yanlong

2017-09-08

A humidity nonsensitive material based on reduced-graphene oxide (r-GO) and methods of making the same are provided, in an embodiment, the materia! has a resistance/humidity variation of about -15% to 15% based on different sintering time or temperature. In an aspect, the resistance variation to humidity can be close to zero or -0.5% to 0.5%, showing a humidity non sensitivity property. In an embodiment, a humidity nonsensitive material based on the r-GO and carbon nanotube (CNT) composites is provided, wherein the ratio of CNT to r-GO is adjusted. The ratio can be adjusted based on the combined contribution of carbon nanotube (positive resistance variation) and reduced- graphene oxide (negative resistance variation) behaviors.
Comparison of field data with a thermodynamic model for the H/sub 2/SO/sub 4/ - HNO/sub 3/ - NH/sub 3/ system at high humidities and in fogs

Energy Technology Data Exchange (ETDEWEB)

Jacob, D.J.; Munger, J.W.; Waldman, J.M.; Hoffmann, M.R.

1986-04-01

A systematic characterization of the atmospheric H/sub 2/SO/sub 4/ - NH/sub 2/ system was conducted in the fogwater, the aerosol, and the gas phase at a network of sites in the San Joaquin Valley of California. Spatial patterns of concentrations were established that reflect the distribution of SO/sub 2/, NO/sub X/, and NH/sub 3/ emissions within the valley. The concept of atmospheric alkalinity was introduced to interpret these concentrations in terms of the buffering capacity of the atmosphere with respect to inputs of strong acids. Regions of predominantly acidic and alkaline fogwater were identified. Fogwater was found to be alkaline in most of the valley, but small changes in emission budgets could lead to widespread acid fog. An extended stagnation episode was studied in detail: progressive accumulation of H/sub 2/SO/sub 4/ - HNO/sub 3/ - NH/sub 3/ species was documented over the course of the episode, and interpreted in terms of production and removal mechanisms. Secondary production of strong acids H/sub 2/SO/sub 4/ and HNO/sub 3/ under stagnant conditions resulted in a complete titration of available alkalinity at sites furthest from NH/sub 3/ sources. A steady SO/sub 2/ conversion rate of 0.4 - 1.1% h/sup -1/ was estimated in the stagnant mixed layer of haze aerosol under overcast conditions, and was attributed to non-photochemical heterogeneous processes. Removal of SO/sub 2/ was enhanced in fog as compared to non-foggy conditions. Conversion of NO/sub X/ to HNO/sub 3/ slowed down during the stagnation episode because of reduced photochemical activity: fog did not appear to enhance conversion of NO/sub X/. Decreases in total HNO/sub 3/ concentrations were observed upon acidification of the atmosphere, and were attributed to displacement of NO/sub 3-/ by H/sub 2/SO/sub 4/ in the aerosol followed by rapid deposition of HNO/sub 3/(g). The occurrence of fog was associated with general decreases of aerosol concentrations due to enhanced removal by deposition.
Influence de l'environnement et des pratiques culturales sur la productivité de Jatropha curcas L. en Afrique subsaharienne (synthèse bibliographique

Directory of Open Access Journals (Sweden)

Minengu, J.

2014-01-01

Full Text Available Influence of environment and cropping practices on the productivity of Jatropha curcas L. in Sub-Saharan Africa. A review. In most sub-Saharan African countries, the establishment of Jatropha curcas L. plantations preceded the scientific investigations necessary to optimize the production of this species. Consequently, the development of the plants was low and yields during the first years of cultivation were mostly disappointing. The low yields obtained in marginal conditions led to the belief that the cultivation of Jatropha could only be profitable in areas with fertile soils and sufficiently humid climates, which would place the plants in direct competition with food production. This article analyzes the available scientific knowledge regarding the ecological and technical factors influencing the productivity of J. curcas and suggests possible solutions for improving its performance in sub-Saharan Africa.
Degradation testing and failure analysis of DC film capacitors under high humidity conditions

DEFF Research Database (Denmark)

Wang, Huai; Nielsen, Dennis Achton; Blaabjerg, Frede

2015-01-01

Metallized polypropylene film capacitors are widely used for high-voltage DC-link applications in power electronic converters. They generally have better reliability performance compared to aluminum electrolytic capacitors under electro-thermal stresses within specifications. However......, the degradation of the film capacitors is a concern in applications exposed to high humidity environments. This paper investigates the degradation of a type of plastic-boxed metallized DC film capacitors under different humidity conditions based on a total of 8700 h of accelerated testing and also post failure...... of interest is also presented. The study enables a better understanding of the humidity-related failure mechanisms and reliability performance of DC film capacitors for power electronics applications....

Impact of management strategies on the global warming potential at the cropping system level

Energy Technology Data Exchange (ETDEWEB)

Goglio, Pietro; Grant, Brian B.; Smith, Ward N. [Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6 (Canada); Desjardins, Raymond L., E-mail: ray.desjardins@agr.gc.ca [Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6 (Canada); Worth, Devon E. [Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, K.W. Neatby Building, Ottawa, Ontario K1A 0C6 (Canada); Zentner, Robert [Swift Current Research Station, Swift Current, Saskatchewan S0E 1A0 (Canada); Malhi, Sukhdev S. [Melfort Research Farm, PO Box 1240, Melfort, Saskatchewan S0E 1A0 (Canada)

2014-08-15

Estimating the greenhouse gas (GHG) emissions from agricultural systems is important in order to assess the impact of agriculture on climate change. In this study experimental data supplemented with results from a biophysical model (DNDC) were combined with life cycle assessment (LCA) to investigate the impact of management strategies on global warming potential of long-term cropping systems at two locations (Breton and Ellerslie) in Alberta, Canada. The aim was to estimate the difference in global warming potential (GWP) of cropping systems due to N fertilizer reduction and residue removal. Reducing the nitrogen fertilizer rate from 75 to 50 kg N ha{sup −1} decreased on average the emissions of N{sub 2}O by 39%, NO by 59% and ammonia volatilisation by 57%. No clear trend for soil CO{sub 2} emissions was determined among cropping systems. When evaluated on a per hectare basis, cropping systems with residue removal required 6% more energy and had a little change in GWP. Conversely, when evaluated on the basis of gigajoules of harvestable biomass, residue removal resulted in 28% less energy requirement and 33% lower GWP. Reducing nitrogen fertilizer rate resulted in 18% less GWP on average for both functional units at Breton and 39% less GWP at Ellerslie. Nitrous oxide emissions contributed on average 67% to the overall GWP per ha. This study demonstrated that small changes in N fertilizer have a minimal impact on the productivity of the cropping systems but can still have a substantial environmental impact. - Highlights: • LCA was combined with DNDC model to estimate the GWP of a cropping system. • N{sub 2}O, NO and NH{sub 3} flux increased by 39% under the higher fertilizer rate. • A change from 75 to 50 kg N ha{sup −1} reduced the GWP per ha and GJ basis by 18%. • N{sub 2}O emissions contributed 67% to the overall GWP of the cropping system. • Small changes in N fertilizer can have a substantial environmental impact.
Ammonia volatilization from crop residues and frozen green manure crops

NARCIS (Netherlands)

Ruijter, de F.J.; Huijsmans, J.F.M.; Rutgers, B.

2010-01-01

Agricultural systems can lose substantial amounts of nitrogen (N). To protect the environment, the European Union (EU) has adopted several directives that set goals to limit N losses. National Emission Ceilings (NEC) are prescribed in the NEC directive for nitrogen oxides and ammonia. Crop residues
Establishment of five cover crops and total soil nutrient extraction in a humid tropical soil in the Peruvian Amazon

Science.gov (United States)

In order to evaluate the establishment of five cover crops and their potential to increase soil fertility through nutrient extraction, an experiment was installed in the Research Station of Choclino, San Martin, Peru. Five cover crops were planted: Arachis pintoi Krapov. & W.C. Greg, Calopogonium m...
Oxidation Behavior of Surface-modified Stainless Steel 316LN in Supercritical-CO{sub 2} Environment

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hwan; Heo, Jin Woo; Kim, Hyunm Yung; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of)

2016-05-15

Compared to other working fluids such as helium or nitrogen, S-CO{sub 2} offers a higher efficiency at operating temperatures of advanced reactors above 550 .deg. C. Moreover, the S-CO{sub 2} cycle is expected to have a significantly smaller footprint compared to other power conversion cycles, resulting in a broader range of applications with lower capital costs. Currently, stainless steel 316 is considered as the candidate structural material for the SFR. In comparison, it is well known that alumina (Al{sub 2}O{sub 3}) have superior oxidation and carburization resistance specifically at higher temperatures where α-Al{sub 2}O{sub 3} may form. Thus, various surface modification techniques have been applied to mostly Ni-base alloys so that a protective and continuous Al-rich oxide layer forms on the surface, conferring superior oxidation and carburization resistance. In this study, SS 316LN was deposited with Al via physical vapor deposition (PVD) method followed by heat treatment processes to develop an Al-rich layer at the surface. The specimens are to be exposed to high temperature S-CO{sub 2} environment to evaluate the oxidation and carburization resistance. Stainless steel 316LN was surface-modified to develop an Al-rich layer for improvement of oxidation behavior in S-CO{sub 2} environment. As the test temperature of 600 .deg. C is not sufficiently high for the formation of protective α-Al{sub 2}O{sub 3} formation, pre-oxidation of surface modified SS 316LN was conducted.
Evaluation of hedgerow trees in alley cropping for phosphorus use efficiency and N{sub 2} fixation in low P soils in moist savanna in Nigeria

Energy Technology Data Exchange (ETDEWEB)

Sanginga, N [International Inst. of Tropical Agriculture, Ibadan (Nigeria); Danso, S K.A. [Joint FAO/IAEA Div. of Nuclear Techniques in Food and Agriculture, Vienna (Austria). Soil Fertility and Crop Production Section; Zapata, F [FAO/IAEA Agriculture and Biotechnology Lab., Seibersdorf (Austria). Soils Science Unit; Bowen, G D [Commonwealth Scientific and Industrial Research Organization, Glen Osmond (Australia). Div. of Soils

1996-07-01

Soils low in P and N are common in the moist savanna climatic zones and consequently growth of hedgerow trees in alley cropping systems might require addition of N and P fertilizers. This is difficult for small scale farmers who have limited access to fertilizers and therefore depend only on limited input cropping systems. Exploiting genetic differences in P use efficiency and using hedgerow trees selected for high N{sub 2} fixation ability can improve tree establishment and growth on N and P-poor soils, restore soil fertility and preserve soil from degradation. Field experiments carried out at Fashola (moist savanna) have shown that large differences in growth and P use efficiency occurred between N{sub 2} fixing trees such as Gliricidia sepium, and non N{sub 2}-fixing trees such as Senna siamea and Senna spectabilis. Provenances or isoline differences in P use efficiency also occurred within species and was also influenced by level of P and period of growth. Differences between species and provenances in P uptake and growth were largely related to differences in physiological P-use efficiency (PPUE), root length and VAM infection rate, especially at low P. In general, nodulation was improved by P application, but varied among provenances. Gliricidia Sepium fixed about 61% of its N from atmospheric N{sub 2} in the pot experiment and 40% in the field. The percentage of N fixed was not affected by rate of P application. Differences in P and N accumulation and use efficiency were also influenced by management practices such as pruning. The distribution of total P followed the same trend as that of dry matter yield, while no significant correlations were found between partitioning of dry matter and total N. Uncut and cut G. Sepium derived 35 and 54% respectively of their N from atmospheric N{sub 2}. About 54% of the fixed N{sub 2} was partitioned to shoots and roots and this was not proportional to the size of these organs relative the whole plant. 17refs,2figs,2tabs.
Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO{sub 2} transformation

Energy Technology Data Exchange (ETDEWEB)

Shanmugam, Ramasamy [Department of Chemistry, Thiagarajar College, Madurai, Tamilnadu 625 009 (India); National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India); Thamaraichelvan, Arunachalam [Faculty of Allied Health Sciences, Chettinad Hospital & Research Institute, Kelambakkam, Tamilnadu 603 103 (India); Ganesan, Tharumeya Kuppusamy [Department of Chemistry, The American College, Madurai, Tamilnadu 625 002 (India); Viswanathan, Balasubramanian, E-mail: bvnathan@iitm.ac.in [National Center for Catalysis Research, Indian Institute of Technology Madras, Chennai, Tamilnadu 600 036 (India)

2017-02-28

Highlights: • On interaction with adsorbate CO{sub 2,} the adsorbent changes its configuration around the metal. • Electron transfer is faster in low coordinative environment of Cu. • CO formation is more favorable on Cu sites with even coordination number. • Cu at coordination number two has a over potential of −0.35 V. - Abstract: Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO{sub 2} to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO{sub 2} to CO at an applied potential of −0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO{sub 2} to various value added chemicals.
Thermal annealing behavior of niobium-implanted {alpha}-Al{sub 2}O{sub 3} under reducing environment

Energy Technology Data Exchange (ETDEWEB)

Jianer, Zeng; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Mingle, Gan; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1997-03-01

Thermal annealing behavior is studied in {alpha}-Al{sub 2}O{sub 3} implanted with {sup 93}Nb{sup +} using RBS/channeling technique and optical absorption spectrometry. The samples with <0001> and <112-bar0> orientations are implanted with 300 keV and 400 keV {sup 93}Nb{sup +} ions. Thermal annealing under reducing environment (Ar+3%H{sub 2}) is employed in the temperature range from 600 to 1000degC to explore unusual materials phase. The annealing up to 1000degC for an hour does not show any essential change in RBS/channeling spectra in two kinds of samples but the significant decrease in the visible region is observed in optical absorption spectra. After annealing at 1000degC for 10 hours, the recovery of the lattice damage is detected by RBS/channeling analysis especially in (112-bar0) sample. In the optical absorption spectra, new absorption envelope appears in the ultraviolet region. The results are related to the formation of niobium metal fine particles, and the sharp distribution is realized especially in (0001) sample. (author)
Assessment of potential greenhouse gas mitigation from changes to crop root mass and architecture

Energy Technology Data Exchange (ETDEWEB)

Paustian, Keith [Booz Allen Hamiltion Inc., McLean, VA (United States); Campbell, Nell [Booz Allen Hamiltion Inc., McLean, VA (United States); Dorich, Chris [Booz Allen Hamiltion Inc., McLean, VA (United States); Marx, Ernest [Booz Allen Hamiltion Inc., McLean, VA (United States); Swan, Amy [Booz Allen Hamiltion Inc., McLean, VA (United States)

2016-01-29

Reducing (and eventually reversing) the increase in greenhouse gases (GHGs) in the atmosphere due to human activities, and thus reducing the extent and severity of anthropogenic climate change, is one of the great challenges facing humanity. While most of the man-caused increase in GHGs has been due to fossil fuel use, land use (including agriculture) currently accounts for about 25% of total GHG emissions and thus there is a need to include emission reductions from the land use sector as part of an effective climate change mitigation strategy. In addition, analyses included in the recent IPCC 5th Climate Change Assessment report suggests that it may not be possible to achieve large enough emissions reductions in the energy, transport and industrial sectors alone to stabilize GHG concentrations at a level commensurate with a less than 2°C global average temperature increase, without the help of a substantial CO2sub> sink (i.e., atmospheric CO2sub> removal) from the land use sector. One of the potential carbon sinks that could contribute to this goal is increasing C storage in soil organic matter on managed lands. This report details a preliminary scoping analysis, to assess the potential agricultural area in the US – where appropriate soil, climate and land use conditions exist – to determine the land area on which ‘improved root phenotype’ crops could be deployed and to evaluate the potential long-term soil C storage, given a set of ‘bounding scenarios’ of increased crop root input and/or rooting depth for major crop species (e.g., row crops (corn, sorghum, soybeans), small grains (wheat, barley, oats), and hay and pasture perennial forages). The enhanced root phenotype scenarios assumed 25, 50 and 100% increase in total root C inputs, in combination with five levels of modifying crop root distributions (i.e., no change and four scenarios with increasing downward shift in root distributions). We also analyzed impacts of greater root
Influence of relative humidity on radiosensitivity of Aspergillus flavus Link. infecting cocoa beans

International Nuclear Information System (INIS)

Amoako-Atta, B.; Odamtten, G.T.; Appiah, V.

1981-01-01

The first part of this paper deals with the moisture sorption isotherms of dried cocoa beans under different relative humidities of 55, 65, 75, 85 or 95%. The second part evaluates the effects of relative humidity (RH), initial moisture content (m.c.) of cocoa beans, and different radiation exposure doses (0, 250, 350, 450, 500 or 550 krad) on Aspergillus flavus spore inoculated cocoa beans kept in fixed RH environmental chamber of 75 or 85% RH post-irradiation for forty days. The results discussed suggest that the m.c. of beans increased from an initial level of 6.4% to 7, 7.8 and 8.9% at 55, 65, and 75% respectively, after a storage period of 6-8 days. However, beans stored under 85% or 95% RH continued to absorb moisture from their respective environments indefinitely during the 64-day storage period. Furthermore, the ambient relative humidity to which the beans are subjected before or after irradiation significantly affect the radiosensitivity of toxigenic A. flavus; the differences in such radiosensitivity are influenced by either the available moisture or the initial m.c. of the beans to the inoculum. The authors conclude from their study that high environmental RH increased the radio-resistance of A. flavus spores making it difficult to establish a radiation decontamination level of practical value under a tropical environment with high ambient relative humidity. (author)
Selection for earlier flowering crop associated with climatic variations in the Sahel.

Directory of Open Access Journals (Sweden)

Yves Vigouroux

Full Text Available Climate changes will have an impact on food production and will require costly adaptive responses. Adapting to a changing environment will be particularly challenging in sub-Saharan Africa where climate change is expected to have a major impact. However, one important phenomenon that is often overlooked and is poorly documented is the ability of agro-systems to rapidly adapt to environmental variations. Such an adaptation could proceed by the adoption of new varieties or by the adaptation of varieties to a changing environment. In this study, we analyzed these two processes in one of the driest agro-ecosystems in Africa, the Sahel. We performed a detailed study in Niger where pearl millet is the main crop and covers 65% of the cultivated area. To assess how the agro-system is responding to recent recurrent drought, we analyzed samples of pearl millet landraces collected in the same villages in 1976 and 2003 throughout the entire cultivated area of Niger. We studied phenological and morphological differences in the 1976 and 2003 collections by comparing them over three cropping seasons in a common garden experiment. We found no major changes in the main cultivated varieties or in their genetic diversity. However, we observed a significant shift in adaptive traits. Compared to the 1976 samples, samples collected in 2003 displayed a shorter lifecycle, and a reduction in plant and spike size. We also found that an early flowering allele at the PHYC locus increased in frequency between 1976 and 2003. The increase exceeded the effect of drift and sampling, suggesting a direct effect of selection for earliness on this gene. We conclude that recurrent drought can lead to selection for earlier flowering in a major Sahelian crop. Surprisingly, these results suggest that diffusion of crop varieties is not the main driver of short term adaptation to climatic variation.
Application of GM crops in Sub-Saharan Africa: lessons learned from Green Revolution.

Science.gov (United States)

Bazuin, Sjoerd; Azadi, Hossein; Witlox, Frank

2011-01-01

While the Green Revolution has been successful in some regions like South and East Asia, it could hardly address any achievement in Sub-Saharan Africa (SSA). This paper tries to draw a picture on lessons learned from the failures of this revolution that should be taken into account before implementing the so-called Gene Revolution in the SSA region. After scrutinizing the failures and the pros and cons of GM crops in the region, the paper introduces some potentials for improving the malnutrition situation in SSA through launching a successful GM technology. However, it remains doubtful whether this technology can improve the situation of small-scale farmers as long as they receive no financial support from their national governments. Therefore, before any intervention, the socio-economic and environmental impacts of GM technology need to be carefully addressed in the framework of a series of risk assessment studies. Besides, some sort of multi-stakeholder dialog (from small-scale farmers to consumers) involving public-private sector and non-governmental organizations should be heated up at both national and regional levels with regard to the myths and truths of this technology. Copyright © 2011 Elsevier Inc. All rights reserved.
The effect of sub-floor heating on house-dust-mite populations on floors and in furniture.

Science.gov (United States)

de Boer, Rob

2003-01-01

It is well known that dehydrating conditions for house dust mites can be created by simply raising the temperature, causing loss of body water and eventually death. Thus, it can be expected that conditions for dust mites are less favourable on floors supplied with sub-floor heating. This was examined in a study of 16 houses with sub-floor heating and 21 without. The pattern of changes in air humidity and temperature on the floors was investigated and compared to known data of the tolerance of dust mites. Also the resident mite populations were compared. Floors with sub-floor heating had, on average, fewer mites, but the difference with unheated floors was small. It was remarkable that mite numbers were also lower in upholstered furniture. Another important observation was that some houses with sub-floor heating had high mite numbers, indicating that this type of heating is compatible with a thriving mite population. Temperature and humidity conditions of heated floors may allow mites not only to survive, but also to remain active in winter. A moderate increase in temperature, a moderate decrease in (absolute) air humidity, or a combination of both, will suffice to keep the humidity all winter below the Critical Equilibrium Humidity, the level of air humidity that is critical for mite growth and reproduction, hence for allergen production. However, it is argued that measures to suppress allergen production by house dust mites are likely to be far more effective if taken in summer rather than in winter.
Adsorption of SO{sub 2} on activated carbon for low gas concentrations

Energy Technology Data Exchange (ETDEWEB)

Zhang, P.; Wanko, H.; Ulrich, J. [Martin-Luther-Universitaet Halle-Wittenberg, Zentrum fuer Ingenieurwissenschaften, Verfahrenstechnik/TVT, Halle (Saale) (Germany)

2007-05-15

Adsorption experiments of SO{sub 2} on activated carbon has been carried out for low concentrations (about 100 ppm) at room temperature (15 to 33 C) with varying humidity in the air. The breakthrough curves show that at high relative humidity or relative higher SO{sub 2} concentration, the load capacity increases with respect to temperature. The humidity of the air is also of benefit to the load capacity of SO{sub 2}. When an adsorption process is interrupted and the activated carbon is kept closed for a while, the SO{sub 2} concentration at the exit of a fixed-bed adsorber is similar to that of the fresh activated carbon and begins at a very low value. It appears that the sorption potential has been refreshed after the storage period. Analysis of desorption experiments by simultaneous thermal analysis combined with mass spectrometry (MS) after loading, shows that the physisorbed SO{sub 2} and H{sub 2}O are desorbed at low temperatures. At higher temperatures, the MS peak of SO{sub 2} and H{sub 2}O occur at the same time. Compared with desorption immediately after loading, after one day, the desorption peak due to the physisorbed SO{sub 2} disappears. From this, it can be concluded that the refreshment of the loading capacity of the activated carbon after storage is mainly due to a change in the nature of the SO{sub 2} from a physisorbed state to a chemisorbed form. The same mechanism leads to a continuous refreshment of the sorption potential by means of a chemical reaction during the adsorption process. (Abstract Copyright [2007], Wiley Periodicals, Inc.)
Low vapour pressure deficit reduces the beneficial effect of elevated CO{sub 2} on growth of N{sub 2}-fixing alfalfa plants

Energy Technology Data Exchange (ETDEWEB)

Luis, I. De; Irigoyen, J.J.; Sanchez-Diaz, M. [Univ. de Navarra, Dept. de Fisioligia Vegetal, Pamplona (Spain)

2002-11-01

Plant responses to elevated CO{sub 2} can be modified by many environmental factors, but very little attention has been paid to the interaction between CO{sub 2} and changes in vapour pressure deficit (VPD). Thirty-day-old alfalfa plants (Medicago sativa L. cv. Aragon), which were inoculated with Sinorhizobium meliloti 102F78 strain, were grown for 1 month in controlled environment chambers at 25/15 deg C, 14 h photoperiod, and 600 mol m{sup -2} s{sup -1} photosynthetic photon flux (PPF), using a factorial combination of CO{sub 2} concentration (400 mol mol{sup -1} or 700 mol mol{sup -1}) and vapour pressure deficit (0.48 kPa or 1.74 kPa, which corresponded to relative humidities of 85% and 45% at 25 deg C, respectively). Elevated CO{sub 2} strongly stimulated plant growth under high VPD conditions, but this beneficial effect was not observed under low VPD. Under low VPD, elevated CO{sub 2} also did not enhance plant photosynthesis, and plant water stress was greatest for plants grown at elevated CO{sub 2} and low VPD. Moreover, plants grown under elevated CO{sub 2} and low VPD had a lower leaf soluble protein and photosynthetic activity (photosynthetic rate and carboxylation efficiency) than plants grown under elevated CO{sub 2} and high VPD. Elevated CO{sub 2} significantly increased leaf adaxial and abaxial temperatures. Because the effects of elevated CO{sub 2} were dependent on vapour pressure deficit, VPD needs to be controlled in experiments studying the effect of elevated CO{sub 2} as well as considered in the extrapolations of results to a warmer, high-CO{sub 2} world. (au)
Use of personalized ventilation for improving health, comfort, and performance at high room temperature and humidity

DEFF Research Database (Denmark)

Melikov, Arsen Krikor; Skwarczynski, Mariusz; Kaczmarczyk, J.

2013-01-01

in five 4-h experiments in a climate chamber. Under the conditions with PV, the subjects were able to control the rate and direction of the supplied personalized flow of clean air. Subjective responses were collected through questionnaires. During all exposures, the subjects were occupied with tasks used......The effect of personalized ventilation (PV) on people's health, comfort, and performance in a warm and humid environment (26 and 28°C at 70% relative humidity) was studied and compared with their responses in a comfortable environment (23°C and 40% relative humidity). Thirty subjects participated...... to assess their performance. Objective measures of tear film stability, concentration of stress biomarkers in saliva, and eye blinking rate were taken. Using PV significantly improved the perceived air quality (PAQ) and thermal sensation and decreased the intensity of Sick Building Syndrome (SBS) symptoms...
Application of artificial intelligence to estimate the reference evapotranspiration in sub-humid Doon valley

Science.gov (United States)

Nema, Manish K.; Khare, Deepak; Chandniha, Surendra K.

2017-11-01

Estimation of evapotranspiration (ET) is an essential component of the hydrologic cycle, which is also requisite for efficient irrigation water management planning and hydro-meteorological studies at both the basin and catchment scales. There are about twenty well-established methods available for ET estimation which depends upon various meteorological parameters and assumptions. Most of these methods are physically based and need a variety of input data. The FAO-56 Penman-Monteith method (PM) for estimating reference evapotranspiration (ET0) is recommend for irrigation scheduling worldwide, because PM generally yields the best results under various climatic conditions. This study investigates the abilities of artificial neural networks (ANN) to improve the accuracy of monthly evaporation estimation in sub-humid climatic region of Dehradun. In the first part of the study, different ANN models, comprising various combinations of training function and number of neutrons were developed to estimate the ET0 and it has been compared with the Penman-Monteith (PM) ET0 as the ideal (observed) ET0. Various statistical approaches were considered to estimate the model performance, i.e. Coefficient of Correlation ( r), Sum of Squared Errors, Root Mean Square Error, Nash-Sutcliffe Efficiency Index (NSE) and Mean Absolute Error. The ANN model with Levenberg-Marquardt training algorithm, single hidden layer and nine number of neutron schema was found the best predicting capabilities for the study station with Coefficient of Correlation ( r) and NSE value of 0.996 and 0.991 for calibration period and 0.990 and 0.980 for validation period, respectively. In the subsequent part of the study, the trend analysis of ET0 time series revealed a rising trend in the month of March, and a falling trend during June to November, except August, with more than 90% significance level and the annual declining rate was found to 1.49 mm per year.
Stability of Ruddlesden–Popper-structured oxides in humid conditions

Energy Technology Data Exchange (ETDEWEB)

Lehtimäki, M.; Yamauchi, H.; Karppinen, M., E-mail: maarit.karppinen@aalto.fi

2013-08-15

Some of layered transition-metal oxides are known to react with atmospheric humidity to form through topotactic intercalation reactions new water-containing layered structures. Here we investigate the influence of oxygen content (7−δ) of the Ruddlesden–Popper-structured Sr{sub 3}FeMO{sub 7−δ} (M=Ni, Mn, Ti) oxides on the water-intercalation reaction. It is found that their oxygen contents influence greatly the reactivity of the phases with water. Other factors possibly affecting the reactivity are discussed on the basis of the present data in combination with a comprehensive review of previous works on Ruddlesden–Popper and related layered oxide phases. - Graphical abstract: Many of the Ruddlesden–Popper-structured A{sub 3}B{sub 2}O{sub 7−δ} oxides readily react with water via intercalation reactions. Three possible factors affecting the water intercalation are identified: oxygen content of the phase, ionic radius of cation A and valence state of cation B. The resultant layered water-derivative phases can be categorised into two groups, depending on the crystal symmetry of the phase. Highlights: • Ruddlesden–Popper oxides A{sub 3}B{sub 2}O{sub 7−δ} often accommodate water via intercalation reaction. • The lower the oxygen content 7−δ is the more readily the intercalation reaction occurs. • The second factor promoting the reaction is the large size of cation A. • The third possible factor is the high valence state of cation B. • Resultant water-derivatives can be categorised into two groups depending on symmetry.
Foregone benefits of important food crop improvements in Sub-Saharan Africa

Science.gov (United States)

2017-01-01

A number of new crops have been developed that address important traits of particular relevance for smallholder farmers in Africa. Scientists, policy makers, and other stakeholders have raised concerns that the approval process for these new crops causes delays that are often scientifically unjustified. This article develops a real option model for the optimal regulation of a risky technology that enhances economic welfare and reduces malnutrition. We consider gradual adoption of the technology and show that delaying approval reduces uncertainty about perceived risks of the technology. Optimal conditions for approval incorporate parameters of the stochastic processes governing the dynamics of risk. The model is applied to three cases of improved crops, which either are, or are expected to be, delayed by the regulatory process. The benefits and costs of the crops are presented in a partial equilibrium that considers changes in adoption over time and the foregone benefits caused by a delay in approval under irreversibility and uncertainty. We derive the equilibrium conditions where the net-benefits of the technology equal the costs that would justify a delay. The sooner information about the safety of the technology arrive, the lower the costs for justifying a delay need to be i.e. it pays more to delay. The costs of a delay can be substantial: e.g. a one year delay in approval of the pod-borer resistant cowpea in Nigeria will cost the country about 33 million USD to 46 million USD and between 100 and 3,000 lives. PMID:28749984
Colorimetric humidity sensor based on liquid composite materials for the monitoring of food and pharmaceuticals.

Science.gov (United States)

Bridgeman, Devon; Corral, Javier; Quach, Ashley; Xian, Xiaojun; Forzani, Erica

2014-09-09

Using supported ionic-liquid membrane (SILM)-inspired methodologies, we have synthesized, characterized, and developed a humidity sensor by coating a liquid composite material onto a hygroscopic, porous substrate. Similar to pH paper, the sensor responds to the environment's relative humidity and changes color accordingly. The humidity indicator is prepared by casting a few microliters of low-toxicity reagents on a nontoxic substrate. The sensing material is a newly synthesized liquid composite that comprises a hygroscopic medium for environmental humidity capture and a color indicator that translates the humidity level into a distinct color change. Sodium borohydride was used to form a liquid composite medium, and DenimBlu30 dye was used as a redox indicator. The liquid composite medium provides a hygroscopic response to the relative humidity, and DenimBlu30 translates the chemical changes into a visual change from yellow to blue. The borate-redox dye-based humidity sensor was prepared, and then Fourier transform infrared spectroscopy, differential scanning calorimetry, and image analysis methods were used to characterize the chemical composition, optimize synthesis, and gain insight into the sensor reactivity. Test results indicated that this new sensing material can detect relative humidity in the range of 5-100% in an irreversible manner with good reproducibility and high accuracy. The sensor is a low-cost, highly sensitive, easy-to-use humidity indicator. More importantly, it can be easily packaged with products to monitor humidity levels in pharmaceutical and food packaging.
Temperature, Humidity and Energy Consumption Forecasting in the Poultry Hall Using Artificial Neural Networknetwork

Directory of Open Access Journals (Sweden)

N Gholamrezaei

2017-10-01

Full Text Available Introduction Energy consumption management is one of the most important issues in poultry halls management. Considering the situation of poultry as one of the largest and most developed industries, it is needed to control growing condition based on world standards. The neural networks as one of the intelligent methods are applied in a lot of fields such as classification, pattern recognition, prediction and modeling of processes. To detect and classify several agricultural crops, a research was conducted based on texture and color feature. The highest classification accuracy for vegetables, grains and fruits with using artificial neural network were 80%, 86% and 70%. In this research, the ability to Multilayer Perceptron (MLP Neural Network in predicting energy consumption, temperature and humidity in different coordinate placement of electronic control unit sensors in the poultry house environment was examined. Materials and Methods The experiments were conducted in a poultry unit (3000 pieces that is located in Fars province, Marvdasht city, Ramjerd town, with dimensions of 32 meters long, 7 meters wide and 2.2 meters height. To determine the appropriate placement of the sensor, 60 different points in terms of length, width and height in poultry were selected. Initially, the data was divided into two datasets. 80 percent of total data as a training set and 20 percent of total data as a test set. From180 observations, 144 data were used to train network and 36 data were used to test the process. There are several criteria for evaluating predictive models that they are mainly based according to the difference between the predicted outputs and actual outputs. To evaluate the performance of the model, two statistical indexes, mean squared error (MSE and the coefficient of determination (R² were used. Results and Discussions In this study, to train artificial neural network for predicting the temperature, humidity and energy consumption, the

Effects of Solutally Dominant Convection on Physical Vapor Transport for a Mixture of Hg{sub 2}Br{sub 2} and Br{sub 2} under Microgravity Environments

Energy Technology Data Exchange (ETDEWEB)

Kim, Geug-Tae [Hannam University, Daejeon (Korea, Republic of); Kown, Moo Hyun [Woosuk University, Wanju (Korea, Republic of)

2014-02-15

The convective flow structures in the vapor phase on earth are shown to be single unicellular, indicating the solutally dominant convection is important. These findings reflect that the total molar fluxes show asymmetrical patterns in a viewpoint of interfacial distributions. With decreasing the gravitational level form 1 g{sub 0} down to 1.0x10{sup -4} g{sub 0}, the total molar fluxes decay first order exponentially. It is also found that the total molar fluxes decay first order exponentially with increasing the partial pressure of component B, PB (Torr) form 5 Torr up to 400 Torr.. Under microgravity environments less than 1 g{sub 0}, a diffusive-convection mode is dominant and, results in much uniformity in front of the crystal regions in comparisons with a normal gravity acceleration of 1 g{sub 0}.
The effect of clothing fit and material of women’s Islamic sportswear on physiological and subjective responses during exercise in warm and humid environment

OpenAIRE

Wibowo Astrid Wahyu Adventri; Wijayanto Titis; Widyastuti Watri; Herliansyah Muhammad Kusumawan

2018-01-01

The purpose of this study was to investigate the effects of clothing fit and material of Islamic sportswear for female on physiological responses and body heat balance during exercise in warm and humid environment. Twelve healthy female students (20.3±0.4 years) exercised wearing four types of women’s Islamic sportswear comprised of two level of clothing fit: loose-fit and tight-fit, and two types of material for sportswear: cotton and polyester on four separate occasions, and in random order...
An integrated model for assessing both crop productivity and agricultural water resources at a large scale

Science.gov (United States)

Okada, M.; Sakurai, G.; Iizumi, T.; Yokozawa, M.

2012-12-01

Agricultural production utilizes regional resources (e.g. river water and ground water) as well as local resources (e.g. temperature, rainfall, solar energy). Future climate changes and increasing demand due to population increases and economic developments would intensively affect the availability of water resources for agricultural production. While many studies assessed the impacts of climate change on agriculture, there are few studies that dynamically account for changes in water resources and crop production. This study proposes an integrated model for assessing both crop productivity and agricultural water resources at a large scale. Also, the irrigation management to subseasonal variability in weather and crop response varies for each region and each crop. To deal with such variations, we used the Markov Chain Monte Carlo technique to quantify regional-specific parameters associated with crop growth and irrigation water estimations. We coupled a large-scale crop model (Sakurai et al. 2012), with a global water resources model, H08 (Hanasaki et al. 2008). The integrated model was consisting of five sub-models for the following processes: land surface, crop growth, river routing, reservoir operation, and anthropogenic water withdrawal. The land surface sub-model was based on a watershed hydrology model, SWAT (Neitsch et al. 2009). Surface and subsurface runoffs simulated by the land surface sub-model were input to the river routing sub-model of the H08 model. A part of regional water resources available for agriculture, simulated by the H08 model, was input as irrigation water to the land surface sub-model. The timing and amount of irrigation water was simulated at a daily step. The integrated model reproduced the observed streamflow in an individual watershed. Additionally, the model accurately reproduced the trends and interannual variations of crop yields. To demonstrate the usefulness of the integrated model, we compared two types of impact assessment of
A Radiosonde Using a Humidity Sensor Array with a Platinum Resistance Heater and Multi-Sensor Data Fusion

Science.gov (United States)

Shi, Yunbo; Luo, Yi; Zhao, Wenjie; Shang, Chunxue; Wang, Yadong; Chen, Yinsheng

2013-01-01

This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes. PMID:23857263
Synergistic interactions within disturbed habitats between temperature, relative humidity and UVB radiation on egg survival in a diadromous fish.

Directory of Open Access Journals (Sweden)

Michael J H Hickford

Full Text Available Anthropogenic impacts, including urbanization, deforestation, farming, and livestock grazing have altered riparian margins worldwide. One effect of changes to riparian vegetation is that the ground-level light, temperature, and humidity environment has also been altered. Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, lays eggs almost exclusively beneath riparian vegetation in tidally influenced reaches of rivers. We hypothesized that the survival of these eggs is greatly affected by the micro-environment afforded by vegetation, particularly relating to temperature, humidity and UVB radiation. We experimentally reduced riparian vegetation height and altered shading characteristics, tracked egg survival, and used small ground-level temperature, humidity and UVB sensors to relate survival to ground-level effects around egg masses. The ground-level physical environment was markedly different from the surrounding ambient conditions. Tall dense riparian vegetation modified ambient conditions to produce a buffered temperature regime with constant high relative humidity, generally above 90%, and negligible UVB radiation at ground-level. Where vegetation height was reduced, frequent high temperatures, low humidity, and high UVB irradiances reduced egg survival by up to 95%. Temperature effects on egg survival were probably indirect, through reduced humidity, because developing eggs are known to survive in a wide range of temperatures. In this study, it was remarkable how such small variations in relatively small sites could have such a large effect on egg survival. It appears that modifications to riparian vegetation and the associated changes in the physical conditions of egg laying sites are major mechanisms affecting egg survival. The impacts associated with vegetational changes through human-induced disturbances are complex yet potentially devastating. These effects are particularly important because they
Heavy metal contamination in soil, food crops and associated health risks for residents of Ropar wetland, Punjab, India and its environs.

Science.gov (United States)

Sharma, Sakshi; Nagpal, Avinash Kaur; Kaur, Inderpreet

2018-07-30

In the present study, an assessment of heavy metal content in soil and food crops (wheat, rice, maize grains and mustard seeds) and associated health risks was carried out for residents of Ropar wetland and its environs. All the soil samples had high cadmium and cobalt contents, whereas, all crop samples had high contents of cobalt and lead. Bioconcentration factor (BCF) analysis indicated that rice grains act as hyper-accumulators of chromium (BCF = 17.98) and copper (BCF = 10.91), whereas, maize grains act as hyper-accumulators of copper (BCF = 30.43). One-way ANOVA suggested that heavy metal content in food crops varied significantly at p ≤ 0.05 for different sites, indicating anthropogenic contribution of heavy metals in agricultural fields. Dietary intake of cobalt via all food crops posed higher non-cancer health risk to residents in comparison to other heavy metals. Chromium posed highest cancer risk through consumption of wheat grains, being staple diet in study area. Copyright © 2018 Elsevier Ltd. All rights reserved.
Photosynthesis of crop plants as influenced by light, carbon dioxide, temperature, and stomatal diffusion resistance

NARCIS (Netherlands)

Gaastra, P.

1959-01-01

The effect was estimated of light intensity, leaf temperature, and C0 2sub> concentration on photosynthetic rate in leaves of crop plants. The potential capacities of photochemical and biochemical processes and of C0 2sub> transport were compared.
Resistance to C0 2sub>
A Black Swan and Sub-continental Scale Dynamics in Humid, Late-Holocene Broadleaf Forests

Science.gov (United States)

Pederson, N.; Dyer, J.; McEwan, R.; Hessl, A. E.; Mock, C. J.; Orwig, D.; Rieder, H. E.; Cook, B. I.

2012-12-01

In humid regions with dense broadleaf-dominated forests where gap-dynamics is the prevailing disturbance regime, paleoecological evidence shows regional-scale changes in forest composition associated with climatic change. To investigate the potential for regional events in late-Holocene forests, we use tree-ring data from 76 populations covering 840,000 km2 and 5.3k tree recruitment dates spanning 1.4 million km2 in the eastern US to investigate the occurrence of simultaneous forest dynamics across a humid region. We compare regional forest dynamics with an independent set of annually-resolved tree ring record of hydroclimate to examine whether climate dynamics might drive forest dynamics in this humid region. In forests where light availability is an important limitation for tree recruitment, we document a pulse of tree recruitment during the mid- to late-1600s across the eastern US. This pulse, which can be inferred as large-scale canopy opening, occurred during an era that multiple proxies indicate as extended drought between two intense pluvial. Principal component analysis of the 76 populations indicates a step-change increase in average ring width during the late-1770s resembling a potential canopy accession event over 42,800 km2 of the southeastern US. Growth-release analysis of populations loading strongly on this eigenvector indicates severe canopy disturbance from 1775-1779 that peaked in 1776. The 1776 event follows a period with extended droughts and severe large-scale frost event. We hypothesize these climatic events lead to elevated tree mortality in the late-1770s and canopy accession for understory trees. Superposed epoch analysis reveals that spikes of elevated canopy disturbance from 1685-1850 CE are significantly associated with drought. Extreme value theory statistics indicates the 1776 event lies beyond the 99.9 quantile and nearly 7 sigmas above the 1685-1850 mean rate of disturbance. The time-series of canopy disturbance from 1685-1850 is so
Measurements of Humidity and Temperature in the Marine Environment during the HEXOS Main Experiment

NARCIS (Netherlands)

Katsaros, K.B.; Cosmo, J. de; Lind, R.J.; Anderson, R.J.; Smith, S.D.; Kraan, R.; Oost, W.A.; Uhlig, K.; Mestayer, P.G.; Larsen, S.E.; Smith, M.H.; Leeuw, G. de

1994-01-01

Accurate measurement of fluctuations in temperature and humidity are needed for determination of the surface evaporation rate and the air-sea sensible heat flux using either the eddy correlation or inertial dissipation method for flux calculations. These measurements are difficult to make over the
Proximate composition of CELSS crops grown in NASA's Biomass Production Chamber

Science.gov (United States)

Wheeler, R. M.; Mackowiak, C. L.; Sager, J. C.; Knott, W. M.; Berry, W. L.

Edible biomass from four crops of wheat (Triticum aestivum L.), four crops of lettuce (Lactuca sativa L.), four crops of potato (Solanum tuberosum L.), and three crops of soybean (Glycine max (L.) Merr.) grown in NASA's CELSS Biomass Production Chamber were analyzed for proximate composition. All plants were grown using recirculating nutrient (hydroponic) film culture with pH and electrical conductivity automatically controlled. Temperature and humidity were controlled to near optimal levels for each species and atmospheric carbon dioxide partial pressures were maintained near 100 Pa during the light cycles. Soybean seed contained the highest percentage of protein and fat, potato tubers and wheat seed contained the highest levels of carbohydrate, and lettuce leaves contained the highest level of ash. Analyses showed values close to data published for field-grown plants with several exceptions: In comparison with field-grown plants, wheat seed had higher protein levels; soybean seed had higher ash and crude fiber levels; and potato tubers and lettuce leaves had higher protein and ash levels. The higher ash and protein levels may have been a result of the continuous supply of nutrients (e.g., potassium and nitrogen) to the plants by the recirculating hydroponic culture.
New calculation method for thermodynamic properties of humid air in humid air turbine cycle – The general model and solutions for saturated humid air

International Nuclear Information System (INIS)

Wang, Zidong; Chen, Hanping; Weng, Shilie

2013-01-01

The article proposes a new calculation method for thermodynamic properties (i.e. specific enthalpy, specific entropy and specific volume) of humid air in humid air turbine cycle. The research pressure range is from 0.1 MPa to 5 MPa. The fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. The new model proposes and verifies the relationship between total gas mixture pressure and gas component pressures. This provides a good explanation of the fundamental behaviors of gas components in gas mixture from a new perspective. Another discovery is that the water vapor component pressure of saturated humid air equals P S , always smaller than its partial pressure (f·P S ) which was believed in the past researches. In the new model, “Local Gas Constant” describes the interaction between similar molecules. “Improvement Factor” is proposed for the first time by this article, and it quantitatively describes the magnitude of interaction between dissimilar molecules. They are combined to fully describe the real thermodynamic properties of humid air. The average error of Revised Dalton's Method is within 0.1% compared to experimentally-based data. - Highlights: • Our new model is suitable to calculate thermodynamic properties of humid air in HAT cycle. • Fundamental behaviors of dry air and water vapor in saturated humid air are explored in depth. • Local-Gas-Constant describes existing alone component and Improvement Factor describes interaction between different components. • The new model proposes and verifies the relationship between total gas mixture pressure and component pressures. • It solves saturated humid air thoroughly and deviates from experimental data less than 0.1%
Humid-air and aqueous corrosion models for corrosion-allowance barrier material

International Nuclear Information System (INIS)

Lee, J.H.; Atkins, J.E.; Andrews, R.W.

1995-01-01

Humid-air and aqueous general and pitting corrosion models (including their uncertainties) for the carbon steel outer containment barrier were developed using the corrosion data from literature for a suite of cast irons and carbon steels which have similar corrosion behaviors to the outer barrier material. The corrosion data include the potential effects of various chemical species present in the testing environments. The atmospheric corrosion data also embed any effects of cyclic wetting and drying and salts that may form on the corroding specimen surface. The humid-air and aqueous general corrosion models are consistent in that the predicted humid-air general corrosion rates at relative humidities between 85 and 100% RH are close to the predicted aqueous general corrosion rates. Using the expected values of the model parameters, the model predicts that aqueous pitting corrosion is the most likely failure mode for the carbon steel outer barrier, and an earliest failure (or initial pit penetration) of the 100-mm thick barrier may occur as early as about 500 years if it is exposed continuously to an aqueous condition at between 60 and 70 degrees C
Injury profile SIMulator, a Qualitative aggregative modelling framework to predict injury profile as a function of cropping practices, and abiotic and biotic environment. II. Proof of concept: design of IPSIM-wheat-eyespot.

Science.gov (United States)

Robin, Marie-Hélène; Colbach, Nathalie; Lucas, Philippe; Montfort, Françoise; Cholez, Célia; Debaeke, Philippe; Aubertot, Jean-Noël

2013-01-01

IPSIM (Injury Profile SIMulator) is a generic modelling framework presented in a companion paper. It aims at predicting a crop injury profile as a function of cropping practices and abiotic and biotic environment. IPSIM's modelling approach consists of designing a model with an aggregative hierarchical tree of attributes. In order to provide a proof of concept, a model, named IPSIM-Wheat-Eyespot, has been developed with the software DEXi according to the conceptual framework of IPSIM to represent final incidence of eyespot on wheat. This paper briefly presents the pathosystem, the method used to develop IPSIM-Wheat-Eyespot using IPSIM's modelling framework, simulation examples, an evaluation of the predictive quality of the model with a large dataset (526 observed site-years) and a discussion on the benefits and limitations of the approach. IPSIM-Wheat-Eyespot proved to successfully represent the annual variability of the disease, as well as the effects of cropping practices (Efficiency = 0.51, Root Mean Square Error of Prediction = 24%; bias = 5.0%). IPSIM-Wheat-Eyespot does not aim to precisely predict the incidence of eyespot on wheat. It rather aims to rank cropping systems with regard to the risk of eyespot on wheat in a given production situation through ex ante evaluations. IPSIM-Wheat-Eyespot can also help perform diagnoses of commercial fields. Its structure is simple and permits to combine available knowledge in the scientific literature (data, models) and expertise. IPSIM-Wheat-Eyespot is now available to help design cropping systems with a low risk of eyespot on wheat in a wide range of production situations, and can help perform diagnoses of commercial fields. In addition, it provides a proof of concept with regard to the modelling approach of IPSIM. IPSIM-Wheat-Eyespot will be a sub-model of IPSIM-Wheat, a model that will predict injury profile on wheat as a function of cropping practices and the production situation.
Effect of humidity on the composition of isoprene photooxidation secondary organic aerosol

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T. B. Nguyen

2011-07-01

Full Text Available The effect of relative humidity (RH on the composition and concentrations of gas-phase products and secondary organic aerosol (SOA generated from the photooxidation of isoprene under high-NOx> conditions was investigated. Experiments were performed with hydrogen peroxide as the OH precursor and in the absence of seed aerosol. The relative yields of most gas-phase products were the same regardless of initial water vapor concentration with exception of hydroxyacetone and glycolaldehyde, which were considerably affected by RH. A significant change was observed in the SOA composition, with many unique condensed-phase products formed under humid (90 % RH vs. dry (<2 % RH conditions, without any detectable effect on the rate and extent of the SOA mass growth. There is a 40 % reduction in the number and relative abundance of distinct particle-phase nitrogen-containing organic compounds (NOC detected by high resolution mass spectrometry. The suppression of condensation reactions, which produce water as a product, is the most important chemical effect of the increased RH. For example, the total signal from oligomeric esters of 2-methylglyceric acid was reduced by about 60 % under humid conditions and the maximum oligomer chain lengths were reduced by 7–11 carbons. Oligomers formed by addition mechanisms, without direct involvement of water, also decreased at elevated RH but to a much smaller extent. The observed reduction in the extent of condensation-type oligomerization at high RH may have substantial impact on the phase characteristics and hygroscopicity of the isoprene aerosol. The reduction in the amount of organic nitrates in the particle phase has implications for understanding the budget of NOC compounds.
Prioritizing Crop Management to Increase Nitrogen Use Efficiency in Australian Sugarcane Crops.

Science.gov (United States)

Thorburn, Peter J; Biggs, Jody S; Palmer, Jeda; Meier, Elizabeth A; Verburg, Kirsten; Skocaj, Danielle M

2017-01-01

Sugarcane production relies on the application of large amounts of nitrogen (N) fertilizer. However, application of N in excess of crop needs can lead to loss of N to the environment, which can negatively impact ecosystems. This is of particular concern in Australia where the majority of sugarcane is grown within catchments that drain directly into the World Heritage listed Great Barrier Reef Marine Park. Multiple factors that impact crop yield and N inputs of sugarcane production systems can affect N use efficiency (NUE), yet the efficacy many of these factors have not been examined in detail. We undertook an extensive simulation analysis of NUE in Australian sugarcane production systems to investigate (1) the impacts of climate on factors determining NUE, (2) the range and drivers of NUE, and (3) regional variation in sugarcane N requirements. We found that the interactions between climate, soils, and management produced a wide range of simulated NUE, ranging from ∼0.3 Mg cane (kg N) -1 , where yields were low (i.e., 5 Mg cane (kg N) -1 in plant crops where yields were high and N inputs low. Of the management practices simulated (N fertilizer rate, timing, and splitting; fallow management; tillage intensity; and in-field traffic management), the only practice that significantly influenced NUE in ratoon crops was N fertilizer application rate. N rate also influenced NUE in plant crops together with the management of the preceding fallow. In addition, there is regional variation in N fertilizer requirement that could make N fertilizer recommendations more specific. While our results show that complex interrelationships exist between climate, crop growth, N fertilizer rates and N losses to the environment, they highlight the priority that should be placed on optimizing N application rate and fallow management to improve NUE in Australian sugarcane production systems. New initiatives in seasonal climate forecasting, decisions support systems and enhanced efficiency
Prioritizing Crop Management to Increase Nitrogen Use Efficiency in Australian Sugarcane Crops

Directory of Open Access Journals (Sweden)

Peter J. Thorburn

2017-09-01

Full Text Available Sugarcane production relies on the application of large amounts of nitrogen (N fertilizer. However, application of N in excess of crop needs can lead to loss of N to the environment, which can negatively impact ecosystems. This is of particular concern in Australia where the majority of sugarcane is grown within catchments that drain directly into the World Heritage listed Great Barrier Reef Marine Park. Multiple factors that impact crop yield and N inputs of sugarcane production systems can affect N use efficiency (NUE, yet the efficacy many of these factors have not been examined in detail. We undertook an extensive simulation analysis of NUE in Australian sugarcane production systems to investigate (1 the impacts of climate on factors determining NUE, (2 the range and drivers of NUE, and (3 regional variation in sugarcane N requirements. We found that the interactions between climate, soils, and management produced a wide range of simulated NUE, ranging from ∼0.3 Mg cane (kg N-1, where yields were low (i.e., <50 Mg ha-1 and N inputs were high, to >5 Mg cane (kg N-1 in plant crops where yields were high and N inputs low. Of the management practices simulated (N fertilizer rate, timing, and splitting; fallow management; tillage intensity; and in-field traffic management, the only practice that significantly influenced NUE in ratoon crops was N fertilizer application rate. N rate also influenced NUE in plant crops together with the management of the preceding fallow. In addition, there is regional variation in N fertilizer requirement that could make N fertilizer recommendations more specific. While our results show that complex interrelationships exist between climate, crop growth, N fertilizer rates and N losses to the environment, they highlight the priority that should be placed on optimizing N application rate and fallow management to improve NUE in Australian sugarcane production systems. New initiatives in seasonal climate forecasting
A generic model for estimating biomass accumulation and greenhouse gas emissions from perennial crops

Science.gov (United States)

Ledo, Alicia; Heathcote, Richard; Hastings, Astley; Smith, Pete; Hillier, Jonathan

2017-04-01

Agriculture is essential to maintain humankind but is, at the same time, a substantial emitter of greenhouse gas (GHG) emissions. With a rising global population, the need for agriculture to provide secure food and energy supply is one of the main human challenges. At the same time, it is the only sector which has significant potential for negative emissions through the sequestration of carbon and offsetting via supply of feedstock for energy production. Perennial crops accumulate carbon during their lifetime and enhance organic soil carbon increase via root senescence and decomposition. However, inconsistency in accounting for this stored biomass undermines efforts to assess the benefits of such cropping systems when applied at scale. A consequence of this exclusion is that efforts to manage this important carbon stock are neglected. Detailed information on carbon balance is crucial to identify the main processes responsible for greenhouse gas emissions in order to develop strategic mitigation programs. Perennial crops systems represent 30% in area of total global crop systems, a considerable amount to be ignored. Furthermore, they have a major standing both in the bioenergy and global food industries. In this study, we first present a generic model to calculate the carbon balance and GHGs emissions from perennial crops, covering both food and bioenergy crops. The model is composed of two simple process-based sub-models, to cover perennial grasses and other perennial woody plants. The first is a generic individual based sub-model (IBM) covering crops in which the yield is the fruit and the plant biomass is an unharvested residue. Trees, shrubs and climbers fall into this category. The second model is a generic area based sub-model (ABM) covering perennial grasses, in which the harvested part includes some of the plant parts in which the carbon storage is accounted. Most second generation perennial bioenergy crops fall into this category. Both generic sub
Floral humidity as a reliable sensory cue for profitability assessment by nectar-foraging hawkmoths.

Science.gov (United States)

von Arx, Martin; Goyret, Joaquín; Davidowitz, Goggy; Raguso, Robert A

2012-06-12

Most research on plant-pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue--transient humidity gradients--using the night blooming flowers of Oenothera cespitosa (Onagraceae). The headspace of newly opened flowers reaches levels of about 4% above ambient relative humidity due to additive evapotranspirational water loss through petals and water-saturated air from the nectar tube. Floral humidity plumes differ from ambient levels only during the first 30 min after anthesis (before nectar is depleted in wild populations), whereas other floral traits (scent, shape, and color) persist for 12-24 h. Manipulative experiments indicated that floral humidity gradients are mechanistically linked to nectar volume and therefore contain information about energy rewards to floral visitors. Behavioral assays with Hyles lineata (Sphingidae) and artificial flowers with appropriate humidity gradients suggest that these hawkmoth pollinators distinguish between subtle differences in relative humidity when other floral cues are held constant. Moths consistently approached and probed flowers with elevated humidity over those with ambient humidity levels. Because floral humidity gradients are largely produced by the evaporation of nectar itself, they represent condition-informative cues that facilitate remote sensing of floral profitability by discriminating foragers. In a xeric environment, this level of honest communication should be adaptive when plant reproductive success is pollinator limited, due to intense competition for the attention of a specialized pollinator.
Floral humidity as a reliable sensory cue for profitability assessment by nectar-foraging hawkmoths

Science.gov (United States)

von Arx, Martin; Goyret, Joaquín; Davidowitz, Goggy; Raguso, Robert A.

2012-01-01

Most research on plant–pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue—transient humidity gradients—using the night blooming flowers of Oenothera cespitosa (Onagraceae). The headspace of newly opened flowers reaches levels of about 4% above ambient relative humidity due to additive evapotranspirational water loss through petals and water-saturated air from the nectar tube. Floral humidity plumes differ from ambient levels only during the first 30 min after anthesis (before nectar is depleted in wild populations), whereas other floral traits (scent, shape, and color) persist for 12–24 h. Manipulative experiments indicated that floral humidity gradients are mechanistically linked to nectar volume and therefore contain information about energy rewards to floral visitors. Behavioral assays with Hyles lineata (Sphingidae) and artificial flowers with appropriate humidity gradients suggest that these hawkmoth pollinators distinguish between subtle differences in relative humidity when other floral cues are held constant. Moths consistently approached and probed flowers with elevated humidity over those with ambient humidity levels. Because floral humidity gradients are largely produced by the evaporation of nectar itself, they represent condition-informative cues that facilitate remote sensing of floral profitability by discriminating foragers. In a xeric environment, this level of honest communication should be adaptive when plant reproductive success is pollinator limited, due to intense competition for the attention of a specialized pollinator. PMID:22645365
Agriculturization in the Argentinean Northern Humid Pampas: the Impact on Soil Structure and Runoff

Science.gov (United States)

Sasal, M. C.; Léonard, J.; Andriulo, A.; Wilson, M. G.

2012-04-01

Argentina is among the countries with the largest cropped area under no-tillage (NT). No tillage was adopted in the northern Humid Pampas to reduce the widespread soil degradation by water erosion. With the advent of genetically modified soybean varieties, NT has developed exponentially. This evolution, combined with the influence of the international market trend, has resulted in large changes in crop sequence composition toward the disappearance of pastures and the expansion of soybean monoculture. The aim of this work was to evaluate the long-term consequences of these changes on the topsoil structure and the way in which the evolution of soil structure relates to the simplification of the crop sequence and to runoff at a regional scale. We analyzed the topsoil structure of 25 sites with Argiudolls having 4 to 29 consecutive years of NT using the cultural profile approach. An intensification sequence index (ISI) was calculated as the ratio between the length of the growth period and the length of the year. Fifteen natural-rainfall runoff plots (100 m2) with 3.5% slope were used to analyze the relationship between soil structural state, crop sequence and runoff for four years. Four types of soil structures were identified and a general pattern of vertical soil structure organization was revealed. The top centimeters of 72% of the sites were dominated by a granular structure. Platy soil structure development was omnipresent: all sites exhibited a horizontal platy structure (wheat/soybean double crop (ISI=0.83) could limit soil structure degradation and reduce runoff and the associated environmental risks.

Yield and Yield Attributes Responses of Soybean (Glycine max L. Merrill to Elevated CO2 and Arbuscular Mycorrhizal Fungi Inoculation in the Humid Transitory Rainforest

Directory of Open Access Journals (Sweden)

Nurudeen ADEYEMI

2017-06-01

Full Text Available Variations in yield components and grain yield of arbuscular mycorrhizal fungi (AMF inoculated soybean varieties (Glycine max L. Merrill grown in CO2 enriched environment in the humid rainforest were tested. A screen house trial was established with soybean varieties (‘TGx 1448-2E’, ‘TGx 1440-1E’ and ‘TGx 1740-2F’, AMF inoculation (with and without and CO2 enrichment (350±50 ppm and 550±50 ppm in open top chamber, arranged in completely randomised design, replicated three times. A field trial was also conducted; the treatments were arranged in a split-split plot configuration fitted into randomised complete block design. In the main plot the variant was CO2 enrichment, the sub-plot consisted of AMF inoculation (with and without, while the sub-sub plot consisted of soybean varieties, replicated three times. Both trials had significantly higher grain yield at elevated CO2 than ambient. This could be attributed to improved yield attributes, more spore count and root colonisation. In both trials, inoculated soybean had significantly higher dry pod weight than un-inoculated, which could suggest the increased grain yield observed on the field. AMF inoculated soybean varieties outperformed un-inoculated in both CO2 enriched and ambient concentrations. AMF inoculated soybean variety ‘TGx 1740-2F’ is most preferable in CO2 enriched environment, while variety ‘TGx 1448-2E’ had the most stable grain yield in all growth environments.
Kinetics of the reaction of iron blast furnace slag/hydrated lime sorbents with SO{sub 2} at low temperatures: effects of the presence of CO{sub 2}, O{sub 2}, and NOx

Energy Technology Data Exchange (ETDEWEB)

Liu, C.F.; Shih, S.M. [Industrial Technological Research Institute, Hsinchu (Taiwan)

2009-09-15

The effects of the presence of CO{sub 2}, O{sub 2}, and NOx in the flue gas on the kinetics of the sulfation of blast furnace slag/hydrated lime sorbents at low temperatures were studied using a differential fixed-bed reactor. When O{sub 2} and NOx were not present simultaneously, the reaction kinetics was about the same as that under the gas mixtures containing SO{sub 2}, H{sub 2}O, and N{sub 2} only, being affected mainly by the relative humidity. The sulfation of sorbents can be described by the surface coverage model and the model equations derived for the latter case. When both O{sub 2} and NOx, were present, the sulfation of sorbents was greatly enhanced, forming a great amount of sulfate in addition to sulfite. The surface coverage model is still valid in this case, but the model equations obtained show a more marked effect of relative humidity and negligible effects of SO{sub 2} concentration and temperature on the reaction. The effect of sorbent composition on the reaction kinetics was entirely represented by the effects of the initial specific surface area (S{sub g0}) and the Ca molar content (M{sup -1}) of sorbent. The initial conversion rate of sorbent increased linearly with increasing S{sub g0}, and the ultimate conversion increased linearly with increasing S{sub g0}M{sup -1}. The model equations obtained in this work are applicable to describe the kinetics of the sulfation of the sorbents in the low-temperature dry and semidry fine gas desulfurization processes either with an upstream NOx, removal unit or without.111
Starch grains reveal early root crop horticulture in the Panamanian tropical forest.

Science.gov (United States)

Piperno, D R; Ranere, A J; Holst, I; Hansell, P

2000-10-19

Native American populations are known to have cultivated a large number of plants and domesticated them for their starch-rich underground organs. Suggestions that the likely source of many of these crops, the tropical forest, was an early and influential centre of plant husbandry have long been controversial because the organic remains of roots and tubers are poorly preserved in archaeological sediments from the humid tropics. Here we report the occurrence of starch grains identifiable as manioc (Manihot esculenta Crantz), yams (Dioscorea sp.) and arrowroot (Maranta arundinacea L.) on assemblages of plant milling stones from preceramic horizons at the Aguadulce Shelter, Panama, dated between 7,000 and 5,000 years before present (BP). The artefacts also contain maize starch (Zea mays L.), indicating that early horticultural systems in this region were mixtures of root and seed crops. The data provide the earliest direct evidence for root crop cultivation in the Americas, and support an ancient and independent emergence of plant domestication in the lowland Neotropical forest.
Optical fiber sensors based on novel polyimide for humidity monitoring of building materials

Science.gov (United States)

Chai, Jing; Liu, Qi; Liu, Jinxuan; Zhang, Dingding

2018-03-01

This paper presents novel preparation methods of polyimide and coupling agent, coated on the fiber Bragg grating (FBG) sensor for monitoring relative humidity (RH). The sensing mechanism that the volume change of the moisture-sensitive polyimide induces the shift of the Bragg wavelength of FBG is used in the RH sensor. The performance of the polymer-coated RH sensor was evaluated under laboratory conditions of temperature over a range of values (20.0-80.0 °C) and humidity over a range of RH values (25.0-95.0%). The time response and RH sensitivity of the sensor based on novel polyimide and coupling agent was improved, compared to the previous. A new packaged RH sensor was designed, which was used in detecting the moisture diffusion and evolutions inside of sample made of building materials which exposed to a controlled environment in the lab after casting. Relative humidity inside of sample with time was 100% in the first phase of vapor-saturated, slowly reduced in the latter phase. The results indicate the RH sensor developed provides a feasible method to detect the influence of environment on moisture inside the material in the drying process.
Variability of N{sub 2}O emissions during the production of poplar and rye

Energy Technology Data Exchange (ETDEWEB)

Kern, Juergen; Hellebrand, Hans Juergen; Scholz, Volkhard [ATB Potsdam (Germany)], E-mail: jkern@atb-potsdam.de

2008-07-01

The emission of N{sub 2}O from the soil has a significant impact on the greenhouse gas balance of energy crops. Soil type, temperature, precipitation, tillage practice and level of fertilization may affect the source strength of N{sub 2}O emissions and fertilizer-induced N{sub 2}O emissions. The N{sub 2}O-fluxes from different sites of an experimental field were measured by the flux chamber method over a period of four years (2003-2006). Poplar and rye as one perennial and one annual crop were fertilized at levels of 0 kg N ha{sup -1} yr{sup -1}, 75 kg N ha{sup -1} yr{sup -1} and 150 kg N ha{sup -1} yr{sup -1}. Enhanced N{sub 2}O emission spots with maxima of up to 1653 {mu}g N{sub 2}O m{sup -2} h{sup -1} were observed at fertilized sites for several weeks. The emissions ranged between 0.4 kg N{sub 2}O-N ha{sup -1} yr{sup -1} and 2.7 kg N{sub 2}O-N ha{sup -1} yr{sup -1} depending on fertilization level, crop variety and year. The mean conversion factor was 2.1% for poplar and 0.9% for rye. The CO{sub 2}-advantage of energy crops is reduced by N{sub 2}O emissions by up to 10%. (author)
Methane and hydrogen production from crop biomass through anaerobic digestion

Energy Technology Data Exchange (ETDEWEB)

Pakarinen, O.

2011-07-01

The feasibility of methane and hydrogen production from energy crops through anaerobic digestion was evaluated in this thesis. The effects of environmental conditions, e.g. pH and temperature, as well as inoculum source on H{sub 2} yield were studied in batch assays. In addition, the effects of pre-treatments on methane and hydrogen yield as well as the feasibility of two-stage H{sub 2} + CH{sub 4} production was evaluated. Moreover, the effect of storage on methane yield of grasses was evaluated. Monodigestion of grass silage for methane production was studied, as well as shifting the methanogenic process to hydrogenic. Hydrogen production from grass silage and maize was shown to be possible with heat-treated inoculum in batch assays, with highest H{sub 2} yields of 16.0 and 9.9 ml gVS{sub added}-1 from untreated grass silage and maize, respectively. Pre-treatments (NaOH, HCl and water-extraction) showed some potential in increasing H{sub 2} yields, while methane yields were not affected. Two-stage H{sub 2} + CH{sub 4} producing process was shown to improve CH{sub 4} yields when compared to traditional one-stage CH{sub 4} process. Methane yield from grass silage monodigestion in continuously stirred tank reactor (CSTR) with organic loading rate (OLR) of 2 kgVS (m3d)-1 and hydraulic retention time (HRT) of 30 days was at most 218 l kgVS{sub fed}-1. Methanogenic process was shifted to hydrogenic by increasing the OLR to 10 kgVS (m3d)-1 and shortening the HRT to 6 days. Highest H{sub 2} yield from grass silage was 42 l kgVS{sub fed}-1 with a maximum H{sub 2} content of 24 %. Energy crops can be successfully stored even for prolonged periods without decrease in methane yield. However, under sub-optimal storage conditions loss in volatile solids (VS) content and methane yield can occur. According to present results energy crops such as grass silage and maize can be converted to hydrogen or methane in AD process. Hydrogen energy yields are typically only 2-5 % of the
Nitrogen Cycling in Agroforestry Systems of Sub-humid Zimbabwe: Closing the loop

NARCIS (Netherlands)

Chikowo, R.

2004-01-01

Keywords: improved fallows, biological N 2sub> -fixation, nitrogen cycling, nitrate leaching, oxide emissions, N mineralization -immobilization, granitic sandsThis thesis focuses on nitrogen: its
Determination of equilibrium humidities using temperature and humidity controlled X-ray diffraction (RH-XRD)

International Nuclear Information System (INIS)

Linnow, Kirsten; Steiger, Michael

2007-01-01

Confined growth of crystals in porous building materials is generally considered to be a major cause of damage. We report on the use of X-ray diffraction under controlled conditions of temperature and relative humidity (RH-XRD) for the investigation of potentially deleterious phase transition reactions. An improved procedure based on rate measurements is used for the accurate and reproducible determination of equilibrium humidities of deliquescence and hydration reactions. The deliquescence humidities of NaCl (75.4 ± 0.5% RH) and Ca(NO 3 ) 2 .4H 2 O (50.8 ± 0.7% RH) at 25 deg. C determined with this improved RH-XRD technique are in excellent agreement with available literature data. Measurement of the hydration of anhydrous Ca(NO 3 ) 2 to form Ca(NO 3 ) 2 .2H 2 O revealed an equilibrium humidity of 10.2 ± 0.3%, which is also in reasonable agreement with available data. In conclusion, dynamic X-ray diffraction measurements are an appropriate method for the accurate and precise determination of equilibrium humidities with a number of interesting future applications
Sulfuric acid nucleation: power dependencies, variation with relative humidity, and effect of bases

Directory of Open Access Journals (Sweden)

J. H. Zollner

2012-05-01

Full Text Available Nucleation of particles composed of sulfuric acid, water, and nitrogen base molecules was studied using a continuous flow reactor. The particles formed from these vapors were detected with an ultrafine condensation particle counter, while vapors of sulfuric acid and nitrogen bases were detected by chemical ionization mass spectrometry. Variation of particle numbers with sulfuric acid concentration yielded a power dependency on sulfuric acid of 5 ± 1 for relative humidities of 14–68% at 296 K; similar experiments with varying water content yielded power dependencies on H2sub>O of ~7. The critical cluster contains about 5 H2sub>SO>4sub> molecules and a new treatment of the power dependency for H2sub>O suggests about 12 H2sub>O molecules for these conditions. Addition of 2-to-45 pptv of ammonia or methyl amine resulted in up to millions of times more particles than in the absence of these compounds. Particle detection capabilities, sulfuric acid and nitrogen base detection, wall losses, and the extent of particle growth are discussed. Results are compared to previous laboratory nucleation studies and they are also discussed in terms of atmospheric nucleation scenarios.
Influence of humidity on the thermal behavior of aluminum nanopowders

International Nuclear Information System (INIS)

Li Ying; Song Wulin; Xie Changsheng; Zeng Dawen; Wang Aihua; Hu Mulin

2006-01-01

Aluminum (Al) nanopowders have increasingly gained attention because of their potential incorporation in explosive and propellant mixtures. This paper reports on a qualitative study on influence of humidity on the thermal behavior of Al nanopowders and the oxidation of aluminum nanoparticles containing a passivating oxide coating. The thermal behaviors were identified by DSC-TG, and Al nanopowders were examined using high-resolution transmission electron microscopy (HRTEM) to understand the stability of the oxide coating in aluminum nanoparticles. It was found that the diameter of Al nanoparticles was in range of 10-100 nm. The original Al nanoparticles were covered by a 3 nm thick compact amorphous oxide layer. After stored for 8 weeks, the oxide layer grew up to 5 nm thick, and the oxidation diffused to the interior of Al nanoparticles. The results indicate that the reactivity of Al nanopowders is deeply influenced by the environment, especially the humidity. The higher relative humidity would accelerate the aging of the Al nanopowders. The DSC-TG results show the oxidation of Al nanoparticles occurs at least in two steps
Increase globe artichoke cropping sustainability using sub-surface drip-irrigation systems in a Mediterranean coastal area for reducing groundwater withdrawal

Science.gov (United States)

Mantino, Alberto; Marchina, Chiara; Bonari, Enrico; Fabbrizzi, Alessandro; Rossetto, Rudy

2017-04-01

During the last decades in coastal areas of the Mediterranean basin, human growth posed severe stresses on freshwater resources due to increasing demand by agricultural, industrial and civil activities, in particular on groundwater. This in turn led to worsening of water quality, loss/reduction of wetlands, up to soil salinization and abandonment of agricultural areas. Within the EU LIFE REWAT project a number of demonstration measures will take place in the lower Cornia valley (Livorno, Italy), both structural (pilot) and non-structural (education, dissemination and capacity building), aiming at achieving sustainable and participated water management. In particular, the five demonstration actions are related to: (1) set up of a managed aquifer recharge facility, (2) restoration of a Cornia river reach, (3) water saving in the civil water supply sector, (4) water saving in agriculture, (5) reuse of treated wastewater for irrigation purposes. Thus, the REWAT project general objective is to develop a new model of governance for sustainable development of the lower Cornia valley based on the water asset at its core. As per water use in agriculture, the lower Cornia valley is well known for the horticultural production. In this regard, globe artichoke (Cynara cardunculus L. var. scolymus L. (Fiori)) crops, a perennial cool-season vegetable, cover a surface of about 600 ha. In order to increase stability and productivity of the crop, about 2000 - 4000 m3 ha-1 yr-1 of irrigation water is required. Recent studies demonstrated that yield of different crops increases using Sub-surface Drip-Irrigation (SDI) system under high frequency irrigation management enhancing water use efficiency. In the SDI systems, the irrigation water is delivered to the plant root zone, below the soil surface by buried plastic tubes containing embedded emitters located at regular spacing. Within the LIFE REWAT, the specific objectives of the pilot on irrigation efficiency is to (i) demonstrate the
Bilayer-structured nanocomposite of Ag and crosslinked polyelectrolyte for the detection of humidity

International Nuclear Information System (INIS)

Li, Yang; Wu, Taotao; Yang, Mujie

2015-01-01

Nanocomposites of quaternized and crosslinked poly(4-vinylpyridine) (QC-P4VP) and silver nanoparticles were prepared by a two-step procedure, and characterized by Fourier-transform infrared spectroscopy, Ultraviolet–visible spectroscopy and scanning electron microscopy. Bilayer-structured humidity sensors based on the nanocomposites were fabricated, and the effects of the concentration of silver salt precursor and poly(4-vinylpyridine), the method for the reduction of silver salt, the deposition order of the sensitive layers and environmental temperature on the humidity sensing characteristics of the composite sensor have been examined at room temperature. The composite sensor exhibited low impedance under dry atmosphere due to the introduction of Ag nanoparticles, and could detect very low relative humidity (RH) (down to 1% RH) with good sensitivity (impedance change of 2000% from 1% to 30% RH). In addition, the composite sensor demonstrated very wide measuring range (1–98% RH), and revealed faster response and smaller hysteresis than the sensor based on QC-P4VP alone. The complex impedance spectra of the composite sensor in the environments with different RH levels were investigated to explore its humidity sensing mechanism. - Highlights: • Bilayer-structured nanocomposite of Ag and polyelectrolyte are facilely prepared. • Nanocomposite could measure humidity as low as 1% RH and show small hysteresis. • Nanocomposite is capable of detecting full-range humidity with high sensitivity
Development of pure Mg open-cell foams as structured CO{sub 2} captor

Energy Technology Data Exchange (ETDEWEB)

Figueroa, I.A., E-mail: iafiguera@unam.mx [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior S/N, Cd. Universitaria, C.P. 04510 México, D.F. (Mexico); Suarez, M.A.; Velasco-Castro, M.; Pfeiffer, H.; Alcántar-Vázquez, B.; González, G. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior S/N, Cd. Universitaria, C.P. 04510 México, D.F. (Mexico); Alfonso, I. [Instituto de Investigaciones en Materiales, Unidad Morelia, Universidad Nacional Autónoma de México, Campus Morelia UNAM, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, C.P. 58190 Morelia, Michoacán (Mexico); Lara-Rodríguez, G.A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior S/N, Cd. Universitaria, C.P. 04510 México, D.F. (Mexico)

2015-12-10

Highlights: • The CO{sub 2} capture capacity of the open-cell Mg foams was studied at low temperatures. • Open-cell Mg foams with pore size of 350 μm were used for the CO{sub 2} capture study. • The highest amount of CO{sub 2} captured was obtained at 60 °C and 80% of relative humidity. • A CO{sub 2} capture capacity of 0.87 mmol/g was obtained for the open-cell Mg foams. • The oxidized open-cell Mg foams can be used as CO{sub 2} captors. - Abstract: The CO{sub 2} capture capacity of the superficial oxide layer formed in pure open-cell Mg foams was studied at low temperatures (40–60 °C) varying the relative humidity from 40 to 80%. Mg foam samples with pore size of 350 μm and surface area of 5.4 m{sup 2}/g were used for these analyses. Optical microscopy and X-ray diffraction techniques were used to characterize the cell structure and the superficial oxide formed in the cell-foams, respectively. The final products formed after the CO{sub 2}–H{sub 2}O capture experiments were identified by scanning electron microscopy and attenuated total reflexion-Fourier transform infrared spectroscopy (ATR-FTIR). The MgCO{sub 3} and other products, formed after CO{sub 2} + H{sub 2}O capture process, were thermally decomposed, to quantify the amount of CO{sub 2} captured by the superficial MgO layer using standard thermogravimetric analysis. The results showed that the highest amount of CO{sub 2} captured was obtained at 60 °C and 80% of relative humidity, with a CO{sub 2} capture capacity of 0.87 mmol/g, which is comparable with others CO{sub 2} MgO-based captors. The considerable CO{sub 2} capture capacity at low temperatures supports the potential of the pure open-cell Mg foams to be used as structured CO{sub 2} captors.
Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

Science.gov (United States)

LeVan, M. Douglas; Finn, John E.

1997-01-01

Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.
Development Requirements for the Exploration PLSS (xPLSS) Carbon Dioxide and Humidity Control Unit (CDHCU)

Science.gov (United States)

Chullen, Cinda

2017-01-01

Functional Requirements for the Carbon Dioxide and Humidity Control Unit (CDHCU): The CDHCU is a component of the Exploration Portable Life Support System (xPLSS) to provide carbon dioxide (CO2) and humidity control within the spacesuit for a crewmember to perform extravehicular activities (EVA) in vacuum (micro-g), lunar, and Mars environments for up to 8 hours continuous, and during EVA preparation in airlocks or support vehicles for an additional 2 hours (TBR) continuous.
Computer-based irrigation scheduling for cotton crop

International Nuclear Information System (INIS)

Laghari, K.Q.; Memon, H.M.

2008-01-01

In this study a real time irrigation schedule for cotton crop has been tested using mehran model, a computer-based DDS (Decision Support System). The irrigation schedule was set on selected MAD (Management Allowable Depletion) and the current root depth position. The total 451 mm irrigation water applied to the crop field. The seasonal computed crop ET (Evapotranspiration) was estimated 421.32 mm and actual (ET/sub ca/) observed was 413 mm. The model over-estimated seasonal ET by only 1.94. WUE (Water Use Efficiency) for seed-cotton achieved 6.59 Kg (ha mm)/sup -1/. The statistical analysis (R/sup 2/=0.96, ARE%=2.00, T-1.17 and F=550.57) showed good performance of the model in simulated and observed ET values. The designed Mehran model is designed quite versatile for irrigation scheduling and can be successfully used as irrigation DSS tool for various crop types. (author)
Hygroscopical behaviour of basic electrodes in a tropical humid climate

International Nuclear Information System (INIS)

Valencia, E.; Galeano, N.J.

1993-01-01

The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)
Molecular, Genetic and Agronomic Approaches to Utilizing Pulses as Cover Crops and Green Manure into Cropping Systems.

Science.gov (United States)

Tani, Eleni; Abraham, Eleni; Chachalis, Demosthenis; Travlos, Ilias

2017-06-05

Cover crops constitute one of the most promising agronomic practices towards a more sustainable agriculture. Their beneficial effects on main crops, soil and environment are many and various, while risks and disadvantages may also appear. Several legumes show a high potential but further research is required in order to suggest the optimal legume cover crops for each case in terms of their productivity and ability to suppress weeds. The additional cost associated with cover crops should also be addressed and in this context the use of grain legumes such as cowpea, faba bean and pea could be of high interest. Some of the aspects of these grain legumes as far as their use as cover crops, their genetic diversity and their breeding using conventional and molecular approaches are discussed in the present review. The specific species seem to have a high potential for use as cover crops, especially if their noticeable genetic diversity is exploited and their breeding focuses on several desirable traits.
Molecular, Genetic and Agronomic Approaches to Utilizing Pulses as Cover Crops and Green Manure into Cropping Systems

Science.gov (United States)

Tani, Eleni; Abraham, Eleni; Chachalis, Demosthenis; Travlos, Ilias

2017-01-01

Cover crops constitute one of the most promising agronomic practices towards a more sustainable agriculture. Their beneficial effects on main crops, soil and environment are many and various, while risks and disadvantages may also appear. Several legumes show a high potential but further research is required in order to suggest the optimal legume cover crops for each case in terms of their productivity and ability to suppress weeds. The additional cost associated with cover crops should also be addressed and in this context the use of grain legumes such as cowpea, faba bean and pea could be of high interest. Some of the aspects of these grain legumes as far as their use as cover crops, their genetic diversity and their breeding using conventional and molecular approaches are discussed in the present review. The specific species seem to have a high potential for use as cover crops, especially if their noticeable genetic diversity is exploited and their breeding focuses on several desirable traits. PMID:28587254
Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching

Science.gov (United States)

Chukalla, A. D.; Krol, M. S.; Hoekstra, A. Y.

2015-12-01

Consumptive water footprint (WF) reduction in irrigated crop production is essential given the increasing competition for freshwater. This study explores the effect of three management practices on the soil water balance and plant growth, specifically on evapotranspiration (ET) and yield (Y) and thus the consumptive WF of crops (ET / Y). The management practices are four irrigation techniques (furrow, sprinkler, drip and subsurface drip (SSD)), four irrigation strategies (full (FI), deficit (DI), supplementary (SI) and no irrigation), and three mulching practices (no mulching, organic (OML) and synthetic (SML) mulching). Various cases were considered: arid, semi-arid, sub-humid and humid environments in Israel, Spain, Italy and the UK, respectively; wet, normal and dry years; three soil types (sand, sandy loam and silty clay loam); and three crops (maize, potato and tomato). The AquaCrop model and the global WF accounting standard were used to relate the management practices to effects on ET, Y and WF. For each management practice, the associated green, blue and total consumptive WF were compared to the reference case (furrow irrigation, full irrigation, no mulching). The average reduction in the consumptive WF is 8-10 % if we change from the reference to drip or SSD, 13 % when changing to OML, 17-18 % when moving to drip or SSD in combination with OML, and 28 % for drip or SSD in combination with SML. All before-mentioned reductions increase by one or a few per cent when moving from full to deficit irrigation. Reduction in overall consumptive WF always goes together with an increasing ratio of green to blue WF. The WF of growing a crop for a particular environment is smallest under DI, followed by FI, SI and rain-fed. Growing crops with sprinkler irrigation has the largest consumptive WF, followed by furrow, drip and SSD. Furrow irrigation has a smaller consumptive WF compared with sprinkler, even though the classical measure of "irrigation efficiency" for furrow

Physiological adaptation to the humid tropics with special reference to the West African Dwarf (WAD) goat.

Science.gov (United States)

Daramola, J O; Adeloye, A A

2009-10-01

West African Dwarf (WAD) goats are widely distributed in the subhumid and humid zones of Africa but are particularly associated with less favourable environments. Adaptive features such as feeding behaviour, efficiency of feed use and disease tolerance enable WAD goats to thrive on natural resources left untouched by other domestic ruminants. In marginal environments this goat remains the only domestic species that is able to survive. Among its physiological features small body size and low metabolic requirements are important traits that enable the animal to minimize its requirements in area or season where food sources are limited in quality and quantity. Specialized feeding behaviour and an efficient digestive system enable the animal to maximize food intake. Coat colour plays an important role in the evolved adaptation of this goat type. Reproductive fitness as manifested by prolific breeding is a major factor of adaptation. Defence mechanisms against infectious agents enable this type to thrive well in the hot humid tropics. The mechanisms involved in the regulation of these physiological functions of WAD goat are discussed. An understanding of these mechanisms could result in the development of improved techniques for enhancing goat productivity in humid environments.
Hierarchical Satellite-based Approach to Global Monitoring of Crop Condition and Food Production

Science.gov (United States)

Zheng, Y.; Wu, B.; Gommes, R.; Zhang, M.; Zhang, N.; Zeng, H.; Zou, W.; Yan, N.

2014-12-01

The assessment of global food security goes beyond the mere estimate of crop production: It needs to take into account the spatial and temporal patterns of food availability, as well as physical and economic access. Accurate and timely information is essential to both food producers and consumers. Taking advantage of multiple new remote sensing data sources, especially from Chinese satellites, such as FY-2/3A, HJ-1 CCD, CropWatch has expanded the scope of its international analyses through the development of new indicators and an upgraded operational methodology. The new monitoring approach adopts a hierarchical system covering four spatial levels of detail: global (sixty-five Monitoring and Reporting Units, MRU), seven major production zones (MPZ), thirty-one key countries (including China) and "sub- countries." The thirty-one countries encompass more that 80% of both global exports and production of four major crops (maize, rice, soybean and wheat). The methodology resorts to climatic and remote sensing indicators at different scales, using the integrated information to assess global, regional, and national (as well as sub-national) crop environmental condition, crop condition, drought, production, and agricultural trends. The climatic indicators for rainfall, temperature, photosynthetically active radiation (PAR) as well as potential biomass are first analysed at global scale to describe overall crop growing conditions. At MPZ scale, the key indicators pay more attention to crops and include Vegetation health index (VHI), Vegetation condition index (VCI), Cropped arable land fraction (CALF) as well as Cropping intensity (CI). Together, they characterise agricultural patterns, farming intensity and stress. CropWatch carries out detailed crop condition analyses for thirty one individual countries at the national scale with a comprehensive array of variables and indicators. The Normalized difference vegetation index (NDVI), cropped areas and crop condition are
Coexistence of Dunes and Humid Conditions at Titan's Tropics

Science.gov (United States)

Radebaugh, Jani; Lorenz, R. D.; Lunine, J. I.; Kirk, R. L.; Ori, G. G.; Farr, T. G.; Malaska, M.; Le Gall, A.; Liu, Z. Y. C.; Encrenaz, P. J.; Paillou, P.; Hayes, A.; Lopes, R. M. C.; Turtle, E. P.; Wall, S. D.; Stofan, E. R.; Wood, C. A.; Cassini RADAR Team

2012-10-01

At Titan's equatorial latitudes there are tens of thousands of dunes, a landform typical of desert environments where sand does not become anchored by vegetation or fluids. Model climate simulations predict generally dry conditions at the equator and humid conditions near the poles of Titan, where lakes of methane/ethane are found. However, moderate relative methane humidity was observed at the Huygens landing site, recent rainfall was seen by Cassini ISS near the Belet Sand Sea, and a putative transient lake in Shangri-La was observed by Cassini VIMS, all of which indicate abundant fluids may be present, at least periodically, at Titan's equatorial latitudes. Terrestrial observations and studies demonstrate dunes can exist and migrate in conditions of high humidity. Active dunes are found in humid climates, indicating the movement of sand is not always prohibited by the presence of fluids. Sand mobility is related to precipitation, evaporation and wind speed and direction. If dune surfaces become wetted by rainfall or rising subsurface fluids, they can become immobilized. However, winds can act to dry the uppermost layers, freeing sands for saltation and enabling dune migration in wet conditions. Active dunes are found in tropical NE Brazil and NE Australia, where there are alternating dry and wet periods, a condition possible for Titan's tropics. Rising and falling water levels lead to the alteration of dune forms, mainly from being anchored by vegetation, but also from cementation by carbonates or clays. Studies of Titan's dunes, which could undergo anchoring of organic sediments by hydrocarbon fluids, could inform the relative strength of vegetation vs. cementation at humid dune regions on Earth. Furthermore, a comprehensive survey of dune morphologies near regions deemed low by SARTopo and stereo, where liquids may collect in wet conditions, could reveal if bodies of liquid have recently existed at Titan's tropics.
Developmental Pathways Are Blueprints for Designing Successful Crops

Directory of Open Access Journals (Sweden)

Ben Trevaskis

2018-06-01

Full Text Available Genes controlling plant development have been studied in multiple plant systems. This has provided deep insights into conserved genetic pathways controlling core developmental processes including meristem identity, phase transitions, determinacy, stem elongation, and branching. These pathways control plant growth patterns and are fundamentally important to crop biology and agriculture. This review describes the conserved pathways that control plant development, using Arabidopsis as a model. Historical examples of how plant development has been altered through selection to improve crop performance are then presented. These examples, drawn from diverse crops, show how the genetic pathways controlling development have been modified to increase yield or tailor growth patterns to suit local growing environments or specialized crop management practices. Strategies to apply current progress in genomics and developmental biology to future crop improvement are then discussed within the broader context of emerging trends in plant breeding. The ways that knowledge of developmental processes and understanding of gene function can contribute to crop improvement, beyond what can be achieved by selection alone, are emphasized. These include using genome re-sequencing, mutagenesis, and gene editing to identify or generate novel variation in developmental genes. The expanding scope for comparative genomics, the possibility to engineer new developmental traits and new approaches to resolve gene–gene or gene–environment interactions are also discussed. Finally, opportunities to integrate fundamental research and crop breeding are highlighted.
Impact of intraoperative temperature and humidity on healing of intestinal anastomoses.

Science.gov (United States)

Glatz, Torben; Boldt, Johannes; Timme, Sylvia; Kulemann, Birte; Seifert, Gabriel; Holzner, Philipp Anton; Chikhladze, Sophia; Grüneberger, Jodok Matthias; Küsters, Simon; Sick, Olivia; Höppner, Jens; Hopt, Ulrich Theodor; Marjanovic, Goran

2014-04-01

Clinical data indicate that laparoscopic surgery has a beneficial effect on intestinal wound healing and is associated with a lower incidence of anastomotic leakage. This observation is based on weak evidence, and little is known about the impact of intraoperative parameters during laparoscopic surgery, e.g., temperature and humidity. A small-bowel anastomosis was formed in rats inside an incubator, in an environment of stable humidity and temperature. Three groups of ten Wistar rats were operated: a control group (G1) in an open surgical environment and two groups (G2 and G3) in the incubator at a humidity of 60 % and a temperature of 30 and 37 °C (G2 and G3, respectively). After 4 days, bursting pressure and hydroxyproline concentration of the anastomosis were analyzed. The tissue was histologically examined. Serum levels of C-reactive-protein (CRP) were measured. No significant changes were seen in the evaluation of anastomotic stability. Bursting pressure was very similar among the groups. Hydroxyproline concentration in G3 (36.3 μg/g) was lower by trend (p = 0.072) than in G1 (51.7 μg/g) and G2 (46.4 μg/g). The histological evaluation showed similar results regarding necrosis, inflammatory cells, edema, and epithelization for all groups. G3 (2.56) showed a distinctly worse score for submucosal bridging (p = 0.061) than G1 (1.68). A highly significant increase (p = 0.008) in CRP was detected in G3 (598.96 ng/ml) compared to G1 (439.49 ng/ml) and G2 (460 ng/ml). A combination of high temperature and humidity during surgery induces an increased systemic inflammatory response and seems to be attenuating the early regeneration process in the anastomotic tissue.
The major economic field diseases of cowpea in the humid agro ...

African Journals Online (AJOL)

Cowpea, which has now become an important protein source for the teeming populace of Nigerians especially those living in the humid agro-ecological zones of South-western Nigeria, is severely attacked by diseases. The causal agents of these diseases find the environment more conducive for survival and hence induce ...
S O{sub 2} emission reduction through the use of the humid oxidation process

Energy Technology Data Exchange (ETDEWEB)

Fink, Jurgen [TIBRAS, Titanio do Brasil S.A., Salvador, BA (Brazil)

1994-12-31

The SO{sub 2} emission reduction unit to be installed in TIBRAS consists of six reactors supplied with activates carbon beds which will remove the SO{sub 2} (0.11 volume percent) contained in the residual gas (150.000 cubic meters per hour) produced in three rotary calciner kilns. The SO{sub 2} reacts with the water in the carbon pores forming diluted sulfuric acid. The activated carbon is fabricated from coke from peat. The weak H{sub 2} SO{sub 4} is reused in the titanium dioxide pigment process. This process is supposed to reduce TIBRAS SO{sub 2} emissions by 50 to 85 percent in addition to eliminating two stacks. 2 figs., 5 tabs.
S O{sub 2} emission reduction through the use of the humid oxidation process

Energy Technology Data Exchange (ETDEWEB)

Fink, Jurgen [TIBRAS, Titanio do Brasil S.A., Salvador, BA (Brazil)

1993-12-31

The SO{sub 2} emission reduction unit to be installed in TIBRAS consists of six reactors supplied with activates carbon beds which will remove the SO{sub 2} (0.11 volume percent) contained in the residual gas (150.000 cubic meters per hour) produced in three rotary calciner kilns. The SO{sub 2} reacts with the water in the carbon pores forming diluted sulfuric acid. The activated carbon is fabricated from coke from peat. The weak H{sub 2} SO{sub 4} is reused in the titanium dioxide pigment process. This process is supposed to reduce TIBRAS SO{sub 2} emissions by 50 to 85 percent in addition to eliminating two stacks. 2 figs., 5 tabs.
Corrosion behaviour of Mg/Al alloys in high humidity atmospheres

Energy Technology Data Exchange (ETDEWEB)

Arrabal, R.; Pardo, A.; Merino, M.C.; Mohedano, M.; Casajus, P. [Facultad de Quimicas, Departamento de Ciencia de Materiales, Universidad Complutense, 28040 Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, Villanueva de la Canada, 28691 Madrid (Spain)

2011-04-15

The influence of relative humidity (80-90-98% RH) and temperature (25 and 50 C) on the corrosion behaviour of AZ31, AZ80 and AZ91D magnesium alloys was evaluated using gravimetric measurements. The results were compared with the data obtained for the same alloys immersed in Madrid tap water. The corrosion rates of AZ alloys increased with the RH and temperature and were influenced by the aluminium content and alloy microstructure for RH values above 90%. The initiation of corrosion was localised around the Al-Mn inclusions in the AZ31 alloy and at the centre of the {alpha}-Mg phase in the AZ80 and AZ91D alloys. The {beta}-Mg{sub 17}Al{sub 12} phase acted as a barrier against corrosion. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Nitrous oxide and methane emissions from optimized and alternative cereal cropping systems on the North China Plain: A two-year field study

Energy Technology Data Exchange (ETDEWEB)

Gao, Bing [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Ju, Xiaotang, E-mail: juxt@cau.edu.cn [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Su, Fang; Meng, Qingfeng [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Oenema, Oene [Wageningen University and Research, Alterra, Wageningen (Netherlands); Christie, Peter [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Agri-Environment Branch, Agri-Food and Biosciences Institute, Belfast BT9 5PX (United Kingdom); Chen, Xinping; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China)

2014-02-01

The impacts of different crop rotation systems with their corresponding management practices on grain yield, greenhouse gas emissions, and fertilizer nitrogen (N) and irrigation water use efficiencies are not well documented. This holds especially for the North China Plain which provides the staple food for hundreds of millions of people and where groundwater resources are polluted with nitrate and depleted through irrigation. Here, we report on fertilizer N and irrigation water use, grain yields, and nitrous oxide (N{sub 2}O) and methane (CH{sub 4}) emissions of conventional and optimized winter wheat–summer maize double-cropping systems, and of three alternative cropping systems, namely a winter wheat–summer maize (or soybean)–spring maize system, with three harvests in two years; and a single spring maize system with one crop per year. The results of this two-year study show that the optimized double-cropping system led to a significant increase in grain yields and a significant decrease in fertilizer N use and net greenhouse gas intensity, but the net greenhouse gas N{sub 2}O emissions plus CH{sub 4} uptake and the use of irrigation water did not decrease relative to the conventional system. Compared to the conventional system the net greenhouse gas emissions, net greenhouse gas intensity and use of fertilizer N and irrigation water decreased in the three alternative cropping systems, but at the cost of grain yields except in the winter wheat–summer maize–spring maize system. Net uptake of CH{sub 4} by the soil was little affected by cropping system. Average N{sub 2}O emission factors were only 0.17% for winter wheat and 0.53% for maize. In conclusion, the winter wheat–summer maize–spring maize system has considerable potential to decrease water and N use and decrease N{sub 2}O emissions while maintaining high grain yields and sustainable use of groundwater. - Highlights: • Yields, resource use efficiency and N{sub 2}O + CH{sub 4} emission
A New Insight into Cross-Sensitivity to Humidity of SnO2 Sensor.

Science.gov (United States)

Zhu, He; Li, Qiang; Ren, Yang; Gao, Qilong; Chen, Jun; Wang, Na; Deng, Jinxia; Xing, Xianran

2018-03-01

The efficiency of gas sensors varies enormously from fundamental study to practical application. This big gap comes mainly from the complex and unpredictable effect of atmospheric environment, especially in humidity. Here, the cross-sensitivity to humidity of a SnO 2 sensor from local structural and lattice evolutions is studied. The sensing response of ethanol is found to be efficiently activated by adsorbing trace of water but inhibited as humidity increases. By X-ray diffraction, pair distribution function of synchrotron and ab initio calculations, the independent effect of water and ethanol on lattice and local structure are clearly revealed, which elucidate the intricate sensing reactions. The formation of hydrogen bonds and repulsion of ethoxides play key roles in the structural distortions, and also in adsorption energies that are critical to the sensitive behavior. The results show the sensor performance coupled with local structural evolution, which provides a new insight into the controversial effects of humidity on SnO 2 sensors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Finger Millet: A "Certain" Crop for an "Uncertain" Future and a Solution to Food Insecurity and Hidden Hunger under Stressful Environments.

Science.gov (United States)

Gupta, Sanjay Mohan; Arora, Sandeep; Mirza, Neelofar; Pande, Anjali; Lata, Charu; Puranik, Swati; Kumar, J; Kumar, Anil

2017-01-01

Crop growth and productivity has largely been vulnerable to various abiotic and biotic stresses that are only set to be compounded due to global climate change. Therefore developing improved varieties and designing newer approaches for crop improvement against stress tolerance have become a priority now-a-days. However, most of the crop improvement strategies are directed toward staple cereals such as rice, wheat, maize etc., whereas attention on minor cereals such as finger millet [ Eleusine coracana (L.) Gaertn.] lags far behind. It is an important staple in several semi-arid and tropical regions of the world with excellent nutraceutical properties as well as ensuring food security in these areas even during harsh environment. This review highlights the importance of finger millet as a model nutraceutical crop. Progress and prospects in genetic manipulation for the development of abiotic and biotic stress tolerant varieties is also discussed. Although limited studies have been conducted for genetic improvement of finger millets, its nutritional significance in providing minerals, calories and protein makes it an ideal model for nutrition-agriculture research. Therefore, improved genetic manipulation of finger millets for resistance to both abiotic and biotic stresses, as well as for enhancing nutrient content will be very effective in millet improvement. Key message: Apart from the excellent nutraceutical value of finger millet, its ability to tolerate various abiotic stresses and resist pathogens make it an excellent model for exploring vast genetic and genomic potential of this crop, which provide us a wide choice for developing strategies for making climate resilient staple crops.
Relation of temperature and humidity to the risk of recurrent gout attacks.

Science.gov (United States)

Neogi, Tuhina; Chen, Clara; Niu, Jingbo; Chaisson, Christine; Hunter, David J; Choi, Hyon; Zhang, Yuqing

2014-08-15

Gout attack risk may be affected by weather (e.g., because of volume depletion). We therefore examined the association of temperature and humidity with the risk of recurrent gout attacks by conducting an internet-based case-crossover study in the United States (in 2003-2010) among subjects with a diagnosis of gout who had 1 or more attacks during 1 year of follow-up. We examined the association of temperature and humidity over the prior 48 hours with the risk of gout attacks using a time-stratified approach and conditional logistic regression. Among 632 subjects with gout, there was a significant dose-response relationship between mean temperature in the prior 48 hours and the risk of subsequent gout attack (P = 0.01 for linear trend). Higher temperatures were associated with approximately 40% higher risk of gout attack compared with moderate temperatures. There was a reverse J-shaped relationship between mean relative humidity and the risk of gout attacks (P = 0.03 for quadratic trend). The combination of high temperature and low humidity had the greatest association (odds ratio = 2.04, 95% confidence interval: 1.26, 3.30) compared with moderate temperature and relative humidity. Thus, high ambient temperature and possibly extremes of humidity were associated with an increased risk of gout attack, despite the likelihood that individuals are often in climate-controlled indoor environments. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
[Characteristics and adaptation of seasonal drought in southern China under the background of climate change. V. Seasonal drought characteristics division and assessment in southern China].

Science.gov (United States)

Huang, Wan-Hua; Sui, Yue; Yang, Xiao-Guang; Dai, Shu-Wei; Li, Mao-Song

2013-10-01

Zoning seasonal drought based on the study of drought characteristics can provide theoretical basis for formulating drought mitigation plans and improving disaster reduction technologies in different arid zones under global climate change. Based on the National standard of meteorological drought indices and agricultural drought indices and the 1959-2008 meteorological data from 268 meteorological stations in southern China, this paper analyzed the climatic background and distribution characteristics of seasonal drought in southern China, and made a three-level division of seasonal drought in this region by the methods of combining comprehensive factors and main factors, stepwise screening indices, comprehensive disaster analysis, and clustering analysis. The first-level division was with the annual aridity index and seasonal aridity index as the main indices and with the precipitation during entire year and main crop growing season as the auxiliary indices, dividing the southern China into four primary zones, including semi-arid zone, sub-humid zone, humid zone, and super-humid zone. On this basis, the four primary zones were subdivided into nine second-level zones, including one semi-arid area-temperate-cold semi-arid hilly area in Sichuan-Yunnan Plateau, three sub-humid areas of warm sub-humid area in the north of the Yangtze River, warm-tropical sub-humid area in South China, and temperate-cold sub-humid plateau area in Southwest China, three humid areas of temperate-tropical humid area in the Yangtze River Basin, warm-tropical humid area in South China, and warm humid hilly area in Southwest China, and two super-humid areas of warm-tropical super-humid area in South China and temperate-cold super-humid hilly area in the south of the Yangtze River and Southwest China. According to the frequency and intensity of multiple drought indices, the second-level zones were further divided into 29 third-level zones. The distribution of each seasonal drought zone was
Genetically modified crops and small-scale farmers: main opportunities and challenges.

Science.gov (United States)

Azadi, Hossein; Samiee, Atry; Mahmoudi, Hossein; Jouzi, Zeynab; Khachak, Parisa Rafiaani; De Maeyer, Philippe; Witlox, Frank

2016-01-01

Although some important features of genetically modified (GM) crops such as insect resistance, herbicide tolerance, and drought tolerance might seem to be beneficial for small-scale farmers, the adoption of GM technology by smallholders is still slight. Identifying pros and cons of using this technology is important to understand the impacts of GM crops on these farmers. This article reviews the main opportunities and challenges of GM crops for small-scale farmers in developing countries. The most significant advantages of GM crops include being independent to farm size, environment protection, improvement of occupational health issues, and the potential of bio-fortified crops to reduce malnutrition. Challenges faced by small-scale farmers for adoption of GM crops comprise availability and accessibility of GM crop seeds, seed dissemination and price, and the lack of adequate information. In addition, R&D and production costs in using GM crops make it difficult for these farmers to adopt the use of these crops. Moreover, intellectual property right regulations may deprive resource poor farmers from the advantages of GM technology. Finally, concerns on socio-economic and environment safety issues are also addressed in this paper.
Reconsidering Tree Fruit as Candidate Crops Through the Use of Rapid Cycle Crop Breeding Technologies

Science.gov (United States)

Graham, Gary Thomas

2014-01-01

Tree fruit, although desirable from a crew nutrition and menu diversity perspective, have long been dismissed as candidate crops based on their long juvenile phase, large architecture, low short-term harvest index, and dormancy requirements. Recent developments in Rapid Cycle Crop Breeding (RCCB) have overcome these historical limitations, opening the door to a new era in candidate crop research. Researchers at the United States Department of Agriculture (USDA) have developed FT-construct (Flowering Locus T) dwarf plum lines that have a very short juvenile phase, vine-like architecture, and no obligate dormancy period. In a collaborative research effort, NASA and the USDA are evaluating the performance of these FT-lines under controlled environment conditions relevant to spaceflight.
Simultaneous Improvement in Water Use, Productivity and Albedo Through Crop Structural Modification

Science.gov (United States)

Drewry, D.; Kumar, P.; Long, S.

2014-12-01

Agricultural lands provide a tremendous opportunity to address challenges at the intersection of climate change, food and water security. Global demand for the major grain and seed crops is beginning to outstrip production, while population growth and the expansion of the global middle class have motivated calls for a doubling of food production by the middle of this century. This is occurring as yield gains for the major food crops have stagnated. At current rates of yield improvement this doubling will not be achieved. Plants have evolved to maximize the capture of radiation in the upper leaves, resulting in sub-optimal monoculture crop fields for maximizing productivity and other biogeophysical services. Using the world's most important protein crop, soybean, as an example, we show that by applying numerical optimization to a micrometeorological crop canopy model that significant, simultaneous gains in water use, productivity and reflectivity are possible with no increased demand on resources. Here we apply the MLCan multi-layer canopy biophysical model, which vertically resolves the radiation and micro-environmental variations that stimulate biochemical and ecophysiological functions that govern canopy-atmosphere exchange processes. At each canopy level photosynthesis, stomatal conductance, and energy balance are solved simultaneously for shaded and sunlit foliage. A multi-layer sub-surface model accounts for water availability as a function of root biomass distribution. MLCan runs at sub-hourly temporal resolution, allowing it to capture variability in CO2, water and energy exchange as a function of environmental variability. By modifying total canopy leaf area, its vertical distribution, leaf angle, and shortwave radiation reflectivity, all traits available in most major crop germplasm collections, we show that increases in either productivity (7%), water use (13%) or albedo (34%) could be achieved with no detriment to the other objectives, under United
Studies on the injuries of crops by harmful gases under covering. II. On the mechanism of crop injury due to gaseous nitrogen dioxide. [Eggplant

Energy Technology Data Exchange (ETDEWEB)

Kato, T; Tachibana, S; Inden, T

1974-12-01

The mechanism of crop injury by nitrogen dioxide gas was investigated by exploring kidney bean, cucumber, tomato, egg plant, and spinach plants 6.0 to 17 ppM NO/sub 2/ under various conditions. The application of aqueous oxyethylene decasanol on crop leaves reduced the injury due to the gas, expecially on the lower leaf sides. Leaves exposed to NO/sub 2/ in the dark showed severer injury and contained more nitrite anion than those exposed to NO/sub 2/ in the light. Leaves smeared with an aqueous sodium nitrite solution showed the same type of injury as that induced by NO/sub 2/. After treatment with 3-(3,4-dichlorophenyl)-1,1- dimethylurea, the leaves became more susceptible to the gas even under light and formed more nitrite anion than controls. Plants grown in nitrate-nitrogen cultures were less susceptible to NO/sub 2/ damage than those grown in ammonia-nitrogen cultures or cultures without nitrogen and contained less nitrite anion than others. Plant injury by gaseous nitrogen dioxide appeared to be caused by nitrite anion. Susceptibility to NO/sub 2/ depended on the amount of the gas taken in by stomata and on the physiological activity of the plant which reduces the anion. The reduction is carried out by nitrite reductase. The photochemical reduction by reductase in chloroplasts appears to be related to the injury-reducing effect of light.
Magnetism and local environment model in (Ni/sub 1-c/Co/sub c/)078P014B008 amorphous alloys

International Nuclear Information System (INIS)

Amamou, A.

1976-06-01

The magnetic properties of amorphous alloys (Ni/sub 1-c/Co/sub c/) 0 . 78 P 0 . 14 B 0 . 08 were investigated. The samples were prepared by the splat-cooling method. The Curie temperatures were determined and the magnetization measurements, performed for 1.7 0 K less than or equal to T less than or equal to 270 0 K and fields up to kOe. Ni 0 . 78 P 0 . 14 B 0 . 08 is paramagnetic, whereas Co 0 . 78 P 0 . 14 B 0 . 08 is ferromagnetic until the crystallization temperature (678 0 K). The average moment per cobalt atom is 1.15 μ/sub B/. In (Ni/sub 1-c/Co/sub c/) 0 . 78 P 0 . 14 B 0 . 08 the critical concentration for the paramagnetic-ferromagnetic transition is c approximately equal to 0.15; this transition occurs in an inhomogeneous way. The saturation magnetization in the whole concentration range can be interpreted (as for some crystallized alloys and compounds) by a local environment model, when a reasonable short-range order is assumed. In such a model the magnetic moment per cobalt atom is related merely to the number of its Co first neighbors n/sub Co/. For n/sub Co/ = 0 and 1 the cobalt atom is not magnetic, for n/sub Co/ = 2 and 3 it carries a small moment μ 1 = 0.50μ/sub B/ and for n/sub Co/ greater than 3 it is magnetic with μ 2 = 1.15μ/sub B/ as in Co 0 . 78 P 0 . 14 B 0 . 08 ; the nickel atoms do not carry a substantial moment in the entire concentration range. These features are comparable to those obtained in some crystalline alloys. 3 figures
Effect of concentration, exposure time, temperature, and relative humidity on the toxicity of sulfur dioxide to the spores of Botrytis cinerea

Energy Technology Data Exchange (ETDEWEB)

Couey, H.M.; Uota, M.

1961-12-01

When spores of Botrytis cinerea are exposed to SO/sub 2/ gas, the subsequent reduction in spore germination is quantitatively proportional to the SO/sub 2/ concentration and the exposure time. The toxicity of SO/sub 2/ increases with increasing relative humidity. In an atmosphere of 96% RH, SO/sub 2/ is more than 20 times as effective as at 75% RH. The toxicity also increases about 1.5 times for each 10/sup 0/C rise in temperature between 0/sup 0/ and 30/sup 0/C. 8 references, 4 figures, 1 table.

Thermography to explore plant-environment interactions.

Science.gov (United States)

Costa, J Miguel; Grant, Olga M; Chaves, M Manuela

2013-10-01

Stomatal regulation is a key determinant of plant photosynthesis and water relations, influencing plant survival, adaptation, and growth. Stomata sense the surrounding environment and respond rapidly to abiotic and biotic stresses. Stomatal conductance to water vapour (g s) and/or transpiration (E) are therefore valuable physiological parameters to be monitored in plant and agricultural sciences. However, leaf gas exchange measurements involve contact with leaves and often interfere with leaf functioning. Besides, they are time consuming and are limited by the sampling characteristics (e.g. sample size and/or the high number of samples required). Remote and rapid means to assess g s or E are thus particularly valuable for physiologists, agronomists, and ecologists. Transpiration influences the leaf energy balance and, consequently, leaf temperature (T leaf). As a result, thermal imaging makes it possible to estimate or quantify g s and E. Thermal imaging has been successfully used in a wide range of conditions and with diverse plant species. The technique can be applied at different scales (e.g. from single seedlings/leaves through whole trees or field crops to regions), providing great potential to study plant-environment interactions and specific phenomena such as abnormal stomatal closure, genotypic variation in stress tolerance, and the impact of different management strategies on crop water status. Nevertheless, environmental variability (e.g. in light intensity, temperature, relative humidity, wind speed) affects the accuracy of thermal imaging measurements. This review presents and discusses the advantages of thermal imaging applications to plant science, agriculture, and ecology, as well as its limitations and possible approaches to minimize them, by highlighting examples from previous and ongoing research.
Performance monitoring of an improved disposal trench in a humid environment in a fractured geology

International Nuclear Information System (INIS)

Mills, D.; Razor, J.

1988-01-01

An engineering evaluation of an improved disposal trench at the Maxey Flats Waste Disposal Site is being conducted in order to demonstrate the feasibility of a burial trench suitable for use at a site in a humid environment and underlain by complex and fractured geologic media. This demonstration is one of several proposed final site stabilization alternatives which will have to be evaluated prior to final site closure. Due to requirements in the Central Midwest Compact Commission, no waste generated as a result of the site closure may be disposed in the Commission's disposal site. Hence, the waste will be disposed on-site. The demonstration trench was constructed and filled with waste during the fall of 1985 with final trench capping being completed in July 1986. Since that time the trench has been evaluated utilizing trench settlement monument elevations, leachate production measurements, leachate radionuclide analysis, chemical tracer analysis and trench water balance. Measurements performed to date indicated that the trench lower infiltration barrier has a permeability of about 1E-7 cm/sec. Water balance measurements indicated that less than one percent of the total rainfall crossed the trench capillary barrier. No settlement of the trench cap has been observed. No liquid has appeared in the leachate collection and monitoring sumps
The ameliorative effect of ascorbic acid on the oxidative status, live weight and recovery rate in road transport stressed goats in a hot humid tropical environment.

Science.gov (United States)

Nwunuji, Tanko Polycarp; Mayowa, Opeyemi Onilude; Yusoff, Sabri Mohd; Bejo, Siti-Khairani; Salisi, Shahrom; Mohd, Effendy Abd Wahid

2014-05-01

The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty-four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post-transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity. © 2014 Japanese Society of Animal Science.
nTiO{sub 2} mass transfer and deposition behavior in an aquatic environment

Energy Technology Data Exchange (ETDEWEB)

Wei, Xiuzhen, E-mail: xzwei@zjut.edu.cn; He, Junhui; Wang, Meng; Fang, Jinfeng; Chen, Jinyuan, E-mail: cjy1128@zjut.edu.cn; Lv, Bosheng, E-mail: zjhzlbs@zjut.edu.cn [Zhejiang University of Technology, College of Environment (China)

2016-12-15

Nano-TiO{sub 2} (nTiO{sub 2}) is widely used in industry, and some of it is inevitably released into natural aquatic environments. nTiO{sub 2} can be deposited on the streambed or transported along the stream and streambed, and it can also undergo exchange-transfer processes in these systems. The behavior of nTiO{sub 2} in rivers includes deposition-transfer processes in the stream and exchange-transfer processes between the stream and streambed. In this work, the deposition, mass transfer, exchange, and aggregation behavior of nTiO{sub 2} in a simulated river were studied as a function of the solution pH, stream velocity, and anionic, cationic, and neutral surfactant concentrations. In these experiments, a recirculating flume was used to simulate a natural stream. The nTiO{sub 2} deposition and aggregation phenomena in the river and streambed were characterized. Of the three surfactants studied, the anionic surfactant enhanced the nTiO{sub 2} stability in the river and limited its aggregation most effectively, resulting in slow nTiO{sub 2} deposition and nTiO{sub 2} transport over long distances. This study provides information about nanoparticle transport phenomena in simulated natural aquatic systems.
Origins of streamflow in a crystalline basement catchment in a sub-humid Sudanian zone: The Donga basin (Benin, West Africa): Inter-annual variability of water budget

Science.gov (United States)

Séguis, L.; Kamagaté, B.; Favreau, G.; Descloitres, M.; Seidel, J.-L.; Galle, S.; Peugeot, C.; Gosset, M.; Le Barbé, L.; Malinur, F.; Van Exter, S.; Arjounin, M.; Boubkraoui, S.; Wubda, M.

2011-05-01

SummaryDuring the last quarter of the 20th century, West Africa underwent a particularly intense and generalized drought. During this period, the biggest drops in streamflow were observed in the Sudanian zone rather than in the Sahelian zone, but the reasons are still poorly understood. In 2000, a meso-scale hydrological observatory was set up in the sub-humid Sudanian zone of the Upper Ouémé Valley (Benin). Three embedded catchments of 12-586 km 2 located on a crystalline bedrock were intensively instrumented to document the different terms of the water budget and to identify the main streamflow generating processes and base-flow mechanisms at different scales. Geophysical, hydrological and geochemical data were collected throughout the catchments from 2002 to 2006. Crossing these data helped define their hydrological functioning. The region has seasonal streamflow, and the permanent groundwater in the weathered mantle does not drain to rivers, instead, seasonal perched groundwaters are the major contributor to annual streamflow. The perched groundwaters are mainly located in seasonally waterlogged sandy layers in the headwater bottom-lands called bas-fonds in French-speaking West Africa of 1st order streams. During the period 2003-2006, regolith groundwater recharge ranged between 10% and 15% of the annual rainfall depth. Depletion of permanent groundwater during the dry season is probably explained by local evapotranspiration which was seen not to be limited to gallery forests. During the 4-year study period, a reduction of 20% in annual rainfall led to a 50% reduction in streamflow. This reduction was observed in the two components of the flow: direct runoff and drainage of perched groundwater. Thanks to the comprehensive dataset obtained, the results obtained for the Donga experimental catchment are now being extrapolated to the whole upper Ouémé valley, which can be considered as representative of sub-humid Sudanian rivers flowing on a crystalline
Performance analysis of spring wheat genotypes under rain-fed conditions in warm humid environment of Nepal

Directory of Open Access Journals (Sweden)

Ramesh Raj Puri

2015-06-01

Full Text Available Around 25% of total wheat area in Terai of Nepal falls under rain-fed and partially irrigated condition. A Coordinated varietal trial (CVT was conducted during two consecutive crop cycles (2011-12 and 2012-13 under timely sown rain-fed conditions of Terai. The trial was conducted in Alpha Lattice design with two replications at Nepal Agricultural Research Council, National Wheat Research Program, Bhairahawa and Nepal Agricultural Research Council, Regional Agriculture Research Station, Nepalgunj. Observations were recorded for yield and yield traits and analyzed using statistical software Cropstat 7.2.The combined analysis of coordinated varietal trial showed that BL 3978 possessed the highest yield (2469.2 Kg ha-1 followed by NL 1097 (2373.2 Kg ha-1 and NL 1094 (2334.06 Kg ha-1. Genotype x Environment interaction for grain yield was significant (p<0.05 over locations and years. BL 3978 with early maturity (111 days escaped the heat stress environment. Among the top three genotypes, BL 3978 was consistently higher in both favorable and unfavorable conditions. Earliness was one of the major traits for heat tolerant genotypes. The three identified genotypes will be further evaluated in participatory varietal selection or coordinated farmers field trial followed by small plot seed multiplication (seed increase and release in the future for timely sown rain-fed conditions. These lines also appear suitable for inclusion in crossing program targeted for water stress tolerance variety development. DOI: http://dx.doi.org/10.3126/ije.v4i2.12649 International Journal of Environment Vol.4(2 2015: 289-295
Remote Sensing and Cropping Practices: A Review

Directory of Open Access Journals (Sweden)

Agnès Bégué

2018-01-01

Full Text Available For agronomic, environmental, and economic reasons, the need for spatialized information about agricultural practices is expected to rapidly increase. In this context, we reviewed the literature on remote sensing for mapping cropping practices. The reviewed studies were grouped into three categories of practices: crop succession (crop rotation and fallowing, cropping pattern (single tree crop planting pattern, sequential cropping, and intercropping/agroforestry, and cropping techniques (irrigation, soil tillage, harvest and post-harvest practices, crop varieties, and agro-ecological infrastructures. We observed that the majority of the studies were exploratory investigations, tested on a local scale with a high dependence on ground data, and used only one type of remote sensing sensor. Furthermore, to be correctly implemented, most of the methods relied heavily on local knowledge on the management practices, the environment, and the biological material. These limitations point to future research directions, such as the use of land stratification, multi-sensor data combination, and expert knowledge-driven methods. Finally, the new spatial technologies, and particularly the Sentinel constellation, are expected to improve the monitoring of cropping practices in the challenging context of food security and better management of agro-environmental issues.
The Crop Journal: A new scientific journal for the global crop science community

Directory of Open Access Journals (Sweden)

Jianmin Wan

2013-10-01

Full Text Available As global population increases and demands for food supplies become greater, we face great challenges in providing more products and in larger quantities from less arable land. Crop science has gained increasing importance in meeting these challenges and results of scientific research must be communicated worldwide on a regular basis. In many countries, however, crop scientists have to publish the results of their investigations in national journals with heterogeneous contents and in their native languages. As a consequence, valuable work often remains unknown to scientists elsewhere. As a big country with a large number of crop scientists, China has a wide range of climatic and ecological environments, diverse plant species and cropping systems, and different regional needs for food supplies, which justify the recent decision by the Crop Science Society of China and the Institute of Crop Science within the Chinese Academy of Agricultural Sciences, to launch a new communication channel, The Crop Journal. The goal of The Crop Journal is to meet an urgent need for a major Asia-based journal that covers the diverse fields of crop science. Our aim is to create a vital and thought-provoking journal that will highlight state-of-the-art original work and reviews by high-profile crop scientists and investigative groups throughout the world — a journal that will respond to the needs of specialists in strategic crop research. We will work with scientific and publishing colleagues worldwide, using The Plant Journal and Crop Science as models, to establish The Crop Journal as a broadly based high quality journal and a premier forum for issues in crop science. The Crop Journal will cover a wide range of topics, including crop genetics, breeding, agronomy, crop physiology, germplasm resources, grain chemistry, grain storage and processing, crop management practices, crop biotechnology, and biomathematics. The journal also encourages the submission of review
Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System

Science.gov (United States)

Chen, Ling-Hsi

2018-01-01

Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories. PMID:29466313
Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System.

Science.gov (United States)

Chen, Ling-Hsi; Chen, Chiachung

2018-02-21

Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories.
Thermal stability of diamond-like carbon–MoS{sub 2} thin films in different environments

Energy Technology Data Exchange (ETDEWEB)

Niakan, H., E-mail: hamid.niakan@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y. [Canadian Light Source, 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada); Szpunar, J.A.; Yang, Q. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada)

2014-07-01

Diamond-like carbon (DLC) based coatings are ideal for low friction and wear resistant applications. For those tribological applications, the coatings may expose to high temperature environments. Therefore, the thermal stability of the coating is very important for its long-term performance. In this work, DLC–MoS{sub 2} composite thin films were synthesized using biased target ion beam deposition technique in which MoS{sub 2} was produced by sputtering a MoS{sub 2} target using Ar ion beams while DLC was deposited by an ion source with CH{sub 4} gas as carbon source. DLC films without MoS{sub 2} deposited under similar conditions were used as reference samples. After the deposition, DLC and DLC–MoS{sub 2} thin films were heat-treated in ambient air and low pressure environments at different temperatures ranging from 100 to 600 °C for 2 h. The effect of annealing on the structure, mechanical and tribological properties of the resulting films were studied by means of Raman spectroscopy, X-ray absorption near edge structure, scanning electron microscopy, nanoindentation, and ball-on-disk testing. The results showed that the structure, hardness, Young's modulus, friction coefficient and wear coefficient of the DLC films were stable up to 200 °C annealing in air and 300 °C in low pressure. At higher temperature, the annealing led to the transformation of sp{sup 3} to sp{sup 2}, which degraded the mechanical and tribological properties of the thin films. Comparing with the DLC films, the DLC–MoS{sub 2} thin films showed a slower rate of graphitization and higher structure stability throughout the range of annealing temperatures, indicating a relatively higher thermal stability. - Highlights: • Thermal stability of diamond-like carbon (DLC) and DLC–MoS{sub 2} films were evaluated. • DLC–MoS{sub 2} films can be synthesized by biased target ion beam deposition technique. • Comparing with DLC films, the DLC–MoS{sub 2} thin films showed higher
Graphene based humidity-insensitive films

KAUST Repository

Tai, Yanlong; Lubineau, Gilles

2017-01-01

A humidity nonsensitive material based on reduced-graphene oxide (r-GO) and methods of making the same are provided, in an embodiment, the materia! has a resistance/humidity variation of about -15% to 15% based on different sintering time
Comparison of the performance of net radiation calculation models

DEFF Research Database (Denmark)

Kjærsgaard, Jeppe Hvelplund; Cuenca, R.H.; Martinez-Cob, A.

2009-01-01

. The long-wave radiation models included a physically based model, an empirical model from the literature, and a new empirical model. Both empirical models used only solar radiation as required for meteorological input. The long-wave radiation models were used with model calibration coefficients from......Daily values of net radiation are used in many applications of crop-growth modeling and agricultural water management. Measurements of net radiation are not part of the routine measurement program at many weather stations and are commonly estimated based on other meteorological parameters. Daily...... values of net radiation were calculated using three net outgoing long-wave radiation models and compared to measured values. Four meteorological datasets representing two climate regimes, a sub-humid, high-latitude environment and a semi-arid mid-latitude environment, were used to test the models...
Rice in cropping systems - Modelling transitions between flooded and non-flooded soil environments

NARCIS (Netherlands)

Gaydon, D.S.; Probert, M.E.; Buresh, R.J.; Meinke, H.B.; Suriadi, A.; Dobermann, A.; Bouman, B.A.M.; Timsina, J.

2012-01-01

Water shortages in many rice-growing regions, combined with growing global imperatives to increase food production, are driving research into increased water use efficiency and modified agricultural practices in rice-based cropping systems. Well-tested cropping systems models that capture
Corrosion behaviour of AZ91D and AM50 magnesium alloys with Nd and Gd additions in humid environments

Energy Technology Data Exchange (ETDEWEB)

Arrabal, R., E-mail: raularrabal@quim.ucm.es [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Matykina, E.; Pardo, A.; Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Paucar, K. [Gabinete de Corrosion, Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, Cod. Postal 25, Lima (Peru); Mohedano, M.; Casajus, P. [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Mg alloys with additions of Nd and Gd were exposed to high humidity atmosphere. Black-Right-Pointing-Pointer The increase of Nd or Gd diminished the effect of micro-galvanic couples. Black-Right-Pointing-Pointer Corrosion resistance of the AM50 alloy improved with the addition of Nd or Gd by 43%. Black-Right-Pointing-Pointer Nd and Gd had no significant effect on the corrosion resistance of the AZ91D alloy. - Abstract: AM50 and AZ91D alloys modified with rare earths (RE) were evaluated under atmospheric conditions. Nd and Gd additions resulted in formation of Al{sub 2}RE and Al-Mn-RE compounds and reduction of the fraction of {beta}-phase. According to surface potential maps, RE-containing intermetallics were more noble than the {beta}-phase, but less than Al-Mn inclusions. As a result, the action of micro-galvanic couples depended on the added amount of RE and the initial alloy microstructure. Nd or Gd additions improved the corrosion resistance of the AM50 alloy by up to 43%, but had no significant effect on the corrosion resistance of the AZ91D alloy.
On the mechanisms of the corrosion of weathering steel by SO{sub 2} in laboratory studies: influence of the environmental parameters

Energy Technology Data Exchange (ETDEWEB)

Marco, J. F., E-mail: jfmarco@iqfr.csic.es [Instituto de Química Física “Rocasolano”, CSIC (Spain)

2017-11-15

We report here on the mechanisms underlying the corrosion of weathering steel in accelerated laboratory tests using artificially polluted SO{sub 2}-atmospheres. The role of corrosion parameters such as the SO{sub 2} concentration, the exposure time, the relative humidity and temperature of the environment are discussed in detail. Through the extensive use of Mössbauer spectroscopy in both its transmission and electron detection modes, as well as with the help of other analysis techniques, the characterization of the different corrosion products at the various stages of the corrosion process has been carried out. The results complement the data obtained in field studies and help to understand the mechanisms involved in this complex phenomenon.
GENETICALLY MODIFIED FOOD CROPS AND PUBLIC HEALTH

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Alejandro Chaparro Giraldo

2008-09-01

Full Text Available The progress made in plant biotechnology has provided an opportunity to new food crops being developed having desirable traits for improving crop yield, reducing the use of agrochemicals and adding nutritional properties to staple crops. However, genetically modified (GM crops have become a subject of intense debate in which opponents argue that GM crops represent a threat to individual freedom, the environment, public health and traditional economies. Despite the advances in food crop agriculture, the current world situation is still characterised by massive hunger and chronic malnutrition, representing a major public health problem. Biofortified GM crops have been considered an important and complementary strategy for delivering naturally-fortified staple foods to malnourished populations. Expert advice and public concern have led to designing strategies for assessing the potential risks involved in cultivating and consuming GM crops. The present critical review was aimed at expressing some conflicting points of view about the potential risks of GM crops for public health. It was concluded that GM food crops are no more risky than those genetically modified by conventional methods and that these GM crops might contribute towards reducing the amount of malnourished people around the world. However, all this needs to be complemented by effective political action aimed at increasing the income of people living below the poverty-line.
IMPACT OF AGRICULTURAL POLICY ON RELATIVE PRICE VARIABILITY OF FOOD CROPS AND INFLATION IN NIGERIA

Directory of Open Access Journals (Sweden)

Ifeoluwa Akin Babalola

2016-08-01

Full Text Available Prices of food crops in Nigeria tend to exhibit similar trend with inflation. The study therefore established quantitatively relationships among agricultural policy, relative price variability (RPV of food crops and inflation in Nigeria. Data for the study includes annual producer prices (nominal and output of food crops and annual inflation rate obtained from the publications of the Central Bank of Nigeria, Nigerian Bureau of Statistics, Food and Agricultural Organisation and Nigerian Institute of Social and Economic Research covering the period of 1970-2009. Analytical tools used were RPV index and Error Correction Method (ECM. The results showed that the variables are stationary at their levels. As inflation increases, RPV of food crops also increases both in short run (0.0002 and the long run (0.0310. Civilian Post-Structural Adjustment Period Policies (CPSAP caused a significant reduction in inflation and consequently reduced the RPV of food crops in the long run. There is a need for policies that will buffer the food crop sub-sector from the effects of inflation. Policies that reduce the rate of inflation and minimise RPV among food crops are needed. Effective management of inefficiencies and misallocation of resources in the sub-sector should be explored.
Controlled humidity gas circulators

International Nuclear Information System (INIS)

Gruner, S.M.

1981-01-01

A programmable circulator capable of regulating the humidity of a gas stream over a wide range of humidity is described. An optical dew-point hygrometer is used as a feedback element to control the addition or removal of water vapor. Typical regulation of the gas is to a dew-point temperature of +- 0.2 0 C and to an accuracy limited by the dew-point hygrometer
Changes in water budgets and sediment yields from a hypothetical agricultural field as a function of landscape and management characteristics--A unit field modeling approach

Science.gov (United States)

Roth, Jason L.; Capel, Paul D.

2012-01-01

humid environments. However, runoff did not increase with slope in the arid environment as was observed in the humid environment. In both environments, clayey soils exhibited the greatest amount of runoff and sediment yields while sandy soils had greater recharge and lessor runoff and sediment yield. Scenarios simulating the effects of the timing and type of tillage practice showed that no-till, conservation, and contouring tillages reduced sediment yields and, with the exception of no-till, runoff in both environments. Changes in land cover and crop type simulated the changes between the evapotransporative potential and surface roughness imparted by specific vegetations. Substantial differences in water budgets and sediment yields were observed between most agricultural crops and the natural covers selected for each environment: scrub and prairie grass for the arid environment and forest and prairie grass for the humid environment. Finally, a group of simulations was performed to model selected agricultural management practices. Among the selected practices subsurface drainage and strip cropping exhibited the largest shifts in water budgets and sediment yields. The practice of crop rotation (corn/soybean) and cover cropping (corn/rye) were predicted to increase sediment yields from a field planted as conventional corn.

Management of Brackish water for crop production under arid and semi-arid conditions

International Nuclear Information System (INIS)

Murtaza, G.; Ghafoor, A.; Akhtar, S.; Shah, S.H.; Mahmood, N.

2005-01-01

For sustainable crop production, changing soil or water chemistry so as to counter the adverse effects of brackish water is a good option. This is normally accomplished by soil or water applied amendments such as gypsum. The other option of blending or cycling brackish and non-brackish water also has merits to reduce the potential hazards. The biological and organic amendments improve soil physical conditions which, otherwise, are expected to be deteriorated by the use of brackish water. Keeping this in view, a field experiment was conducted on a non saline-non sodic sandy loam soil (EC/sub e/ 1.31-1.76 dS m/sup -1/, pH = 8.47-8.61, SAR = 5.50-7.41, infiltration rate 0.6-0.8 cm/h, bulk density = 1.56-1.61 Mg m/sup -3/ for the upper 15 cm soil depth) to evaluate the growth response of cotton crop to different soil and water treatments. Treatments included: T/sub 1/ canal water), T/sub 2/ [tube well water (EC = 3.38 dS m/sup -1/, SAR = 16.43 and RSC = 5.57 mmol/sub c/ L/sup -1/)], T3 [cyclic use (alternate irrigations with canal and tube well waters)], T/sub 4/ (tube well water as such + FYM at the rate of 25 Mg ha/sup -1/annually) and T/sub 5/ (tube well water + gypsum at the rate of water gypsum requirement (WRSC to be decreased up to 00). During the first year of experimentation seed cotton yield was not significantly affected by the applied treatments and was in the decreasing order of: T/sub 3/ (2361 kg ha/sup -1/) > T/sub 4/ (2073 kg ha/sup -1/) > T 1 (2015 kg ha/sup -1/) > T/sub 5/ (2001 kg ha.1 and T 2 (1982 ha/sup -1/. Number of bolls picked per plant was in the decreasing order of: T 2 (33) > T/sub 4/ (32) > T/sub 1/ (31) > T/sub 3/ (30) and T/sub 5/ (26) with non-significant treatment differences. The pH, EC/sub e/ and SAR values remained below safe limits by this cotton (first) crop. (author)
Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

Directory of Open Access Journals (Sweden)

Rodrigo Milton Moraes

2013-03-01

Full Text Available Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil. Carabidae is composed mainly by ground-dwelling predator beetles. It is the fourth most diverse group within Coleoptera, but its diversity in the Neotropical region is understudied. Here we describe and analyze the diversity of carabid beetles in a region of subtropical rain forest dominated by Araucaria angustifolia with different landscapes. Three areas were chosen in an environmental integrity gradient: primary forests, secondary forests and old Pinus plantations. Pitfall traps were taken monthly, in a total of 14 samples per area. 1733 adult carabid beetles, belonging to 18 species, were sampled. There were differences in richness and abundance between the sampled areas. The total scores followed the same tendency: primary forests (14 species/747 individuals, secondary forests (13/631 and Pinus forests (10/355. An analysis of similarity shows differences in species composition, for both areas and seasons. Galerita lacordarei was the most abundant species for all samples and seasons. Carabid species show similar responses in accordance with habitat heterogeneity and disturbance. The abundance of Galerita lacordarei was influenced by temperature, for all sampled sites. Environmental changes affect the carabid assemblages and decrease diversity, possibly interfering in local dynamics. Seasonality patterns seem to indicate an increase in individual movement during summer, probably in search of resources. It is suggested that microhabitat patchiness is probably an important factor affecting carabid beetle diversity at small spatial scales.
Contribution of crop models to adaptation in wheat

DEFF Research Database (Denmark)

Chenu, Karine; Porter, John Roy; Martre, Pierre

2017-01-01

With world population growing quickly, agriculture needs to produce more with fewer inputs while being environmentally friendly. In a context of changing environments, crop models are useful tools to simulate crop yields. Wheat (Triticum spp.) crop models have been evolving since the 1960s...... to translate processes related to crop growth and development into mathematical equations. These have been used over decades for agronomic purposes, and have more recently incorporated advances in the modeling of environmental footprints, biotic constraints, trait and gene effects, climate change impact......, and the upscaling of global change impacts. This review outlines the potential and limitations of modern wheat crop models in assisting agronomists, breeders, and policymakers to address the current and future challenges facing agriculture....
Soil properties, greenhouse gas emissions and crop yield under compost, biochar and co-composted biochar in two tropical agronomic systems

Energy Technology Data Exchange (ETDEWEB)

Bass, Adrian M., E-mail: adrian.bass@glasgow.ac.uk [Centre for Tropical Environmental and Sustainability Science, College of Science, Technology and Engineering, James Cook University, Cairns, Queensland 4870 (Australia); Bird, Michael I. [Centre for Tropical Environmental and Sustainability Science, College of Science, Technology and Engineering, James Cook University, Cairns, Queensland 4870 (Australia); Kay, Gavin [Terrain Natural Resource Management, 2 Stitt Street, Innisfail, Queensland 4860 (Australia); Muirhead, Brian [Northern Gulf Resource Management Group, 317 Byrnes Street, Mareeba, Queensland 4880 (Australia)

2016-04-15

ABSTRACT: The addition of organic amendments to agricultural soils has the potential to increase crop yields, reduce dependence on inorganic fertilizers and improve soil condition and resilience. We evaluated the effect of biochar (B), compost (C) and co-composted biochar (COMBI) on the soil properties, crop yield and greenhouse gas emissions from a banana and a papaya plantation in tropical Australia in the first harvest cycle. Biochar, compost and COMBI organic amendments improved soil properties, including significant increases in soil water content, CEC, K, Ca, NO{sub 3}, NH{sub 4} and soil carbon content. However, increases in soil nutrient content and improvements in physical properties did not translate to improved fruit yield. Counter to our expectations, banana crop yield (weight per bunch) was reduced by 18%, 12% and 24% by B, C and COMBI additions respectively, and no significant effect was observed on the papaya crop yield. Soil efflux of CO{sub 2} was elevated by addition of C and COMBI amendments, likely due to an increase in labile carbon for microbial processing. Our data indicate a reduction in N{sub 2}O flux in treatments containing biochar. The application of B, C and COMBI amendments had a generally positive effect on soil properties, but this did not translate into a crop productivity increase in this study. The benefits to soil nutrient content, soil carbon storage and N{sub 2}O emission reduction need to be carefully weighed against potentially deleterious effects on crop yield, at least in the short-term. - Highlights: • Biochar and compost amendment has potential to improve tropical agriculture. • We monitored soil health, gas fluxes and crop yield under biochar and compost. • Biochar improved soil nutrient content, water retention and reduced N{sub 2}O emissions. • Biochar significantly reduced banana yield performance and did not affect papaya yield. • Organic amendment is not an ‘always win’ scenario for tropical
AOI [3] High-Temperature Nano-Derived Micro-H2sub> and - H2sub>S Sensors

Energy Technology Data Exchange (ETDEWEB)

Sabolsky, Edward M. [West Virginia Univ., Morgantown, WV (United States)

2014-08-01

The emissions from coal-fired power plants remain a significant concern for air quality. This environmental challenge must be overcome by controlling the emission of sulfur dioxide (SO2sub>) and hydrogen sulfide (H2sub>S) throughout the entire coal combustion process. One of the processes which could specifically benefit from robust, low cost, and high temperature compatible gas sensors is the coal gasification process which converts coal and/or biomass into syngas. Hydrogen (H2sub>), carbon monoxide (CO) and sulfur compounds make up 33%, 43% and 2% of syngas, respectively. Therefore, development of a high temperature (>500°C) chemical sensor for in-situ monitoring of H2sub>, H2sub>S and SO22sub> levels during coal gasification is strongly desired. The selective detection of SO2sub>/H>2sub>S in the presence of H2sub>, is a formidable task for a sensor designer. In order to ensure effective operation of these chemical sensors, the sensor system must inexpensively function within harsh temperature and chemical environment. Currently available sensing approaches, which are based on gas chromatography, electrochemistry, and IR-spectroscopy, do not satisfy the required cost and performance targets. This work focused on the development microsensors that can be applied to this application. In order to develop the high- temperature compatible microsensor, this work addressed various issues related to sensor stability, selectivity, and miniaturization. In the research project entitled “High-Temperature Nano-Derived Micro-H2sub> and -H2sub>S Sensors”, the team worked to develop micro-scale, chemical sensors and sensor arrays composed of nano-derived, metal-oxide composite materials to detect gases like H2sub>, SO2sub>, and H2sub>S within high-temperature environments (>500°C). The research was completed in collaboration with NexTech Materials, Ltd. (Lewis Center, Ohio). Nex
Biogas production from high-yielding energy crops in boreal conditions

Energy Technology Data Exchange (ETDEWEB)

Seppala, M.

2013-11-01

In this thesis, the methane production potential of traditional and novel energy crops was evaluated in boreal conditions. The highest methane yield per hectare was achieved with maize (4 000-9 200 m{sup 3}CH{sub 4} ha{sup -1} a{sup -1}) and the second highest with brown knapweed (2 700-6 100 m{sup 3}CH{sub 4} ha{sup -1} a{sup -1}). Recently, the most feasible energy crop, grass, produced 1 200-3 600 m{sup 3}CH{sub 4} ha{sup -1} a{sup -1}. The specific methane yields of traditional and novel energy crops varied from 170-500 l kg{sup -1} volatile solid (VS). The highest specific methane yields were obtained with maize, while the novel energy crops were at a lower range. The specific methane yields decreased in the later harvest time with maize and brown knapweed, and the specific methane yield of the grasses decreased from the 1st to 2nd harvests. Maize and brown knapweed produced the highest total solid (TS) yields per hectare 13-23 tTS ha{sup -1}, which were high when compared with the TS yields of grasses (6-13 tTS ha{sup -1}). The feasibility of maize and brown knapweed in co-digestion with liquid cow manure, in continuously stirred tank reactors (CSTR), was evaluated. According to the CSTR runs, maize and brown knapweed are suitable feeds and have stable processes, producing the highest methane yields (organic loading rate 2 kgVS m{sup -3}d{sup -1}), with maize at 259 l kgVS{sup -1} and brown knapweed at 254 l kgVS{sup -1}. The energy balance (input/output) of the cultivation of the grasses, maize and brown knapweed was calculated in boreal conditions, and it was better when the digestate was used as a fertilizer (1.8-4.8 %) than using chemical fertilizers (3.7-16.2 %), whose production is the most energy demanding process in cultivation. In conclusion, the methane production of maize, grasses and novel energy crops can produce high methane yields and are suitable feeds for anaerobic digestion. The cultivation managements of maize and novel energy crops for
Comment on 'Shang S. 2012. Calculating actual crop evapotranspiration under soil water stress conditions with appropriate numerical methods and time step. Hydrological Processes 26: 3338-3343. DOI: 10.1002/hyp.8405'

Science.gov (United States)

Yatheendradas, Soni; Narapusetty, Balachandrudu; Peters-Lidard, Christa; Funk, Christopher; Verdin, James

2014-01-01

A previous study analyzed errors in the numerical calculation of actual crop evapotranspiration (ET(sub a)) under soil water stress. Assuming no irrigation or precipitation, it constructed equations for ET(sub a) over limited soil-water ranges in a root zone drying out due to evapotranspiration. It then used a single crop-soil composite to provide recommendations about the appropriate usage of numerical methods under different values of the time step and the maximum crop evapotranspiration (ET(sub c)). This comment reformulates those ET(sub a) equations for applicability over the full range of soil water values, revealing a dependence of the relative error in numerical ET(sub a) on the initial soil water that was not seen in the previous study. It is shown that the recommendations based on a single crop-soil composite can be invalid for other crop-soil composites. Finally, a consideration of the numerical error in the time-cumulative value of ET(sub a) is discussed besides the existing consideration of that error over individual time steps as done in the previous study. This cumulative ET(sub a) is more relevant to the final crop yield.
Application of seasonal rainfall forecasts and satellite rainfall observations to crop yield forecasting for Africa

Science.gov (United States)

Greatrex, H. L.; Grimes, D. I. F.; Wheeler, T. R.

2009-04-01

Rain-fed agriculture is of utmost importance in sub-Saharan Africa; the FAO estimates that over 90% of food consumed in the region is grown in rain-fed farming systems. As the climate in sub-Saharan Africa has a high interannual variability, this dependence on rainfall can leave communities extremely vulnerable to food shortages, especially when coupled with a lack of crop management options. The ability to make a regional forecast of crop yield on a timescale of months would be of enormous benefit; it would enable both governmental and non-governmental organisations to be alerted in advance to crop failure and could facilitate national and regional economic planning. Such a system would also enable individual communities to make more informed crop management decisions, increasing their resilience to climate variability and change. It should be noted that the majority of crops in the region are rainfall limited, therefore the ability to create a seasonal crop forecast depends on the ability to forecast rainfall at a monthly or seasonal timescale and to temporally downscale this to a daily time-series of rainfall. The aim of this project is to develop a regional-scale seasonal forecast for sub-Saharan crops, utilising the General Large Area Model for annual crops (GLAM). GLAM would initially be driven using both dynamical and statistical seasonal rainfall forecasts to provide an initial estimate of crop yield. The system would then be continuously updated throughout the season by replacing the seasonal rainfall forecast with daily weather observations. TAMSAT satellite rainfall estimates are used rather than rain-gauge data due to the scarcity of ground based observations. An important feature of the system is the use of the geo-statistical method of sequential simulation to create an ensemble of daily weather inputs from both the statistical seasonal rainfall forecasts and the satellite rainfall estimates. This allows a range of possible yield outputs to be
Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment.

Science.gov (United States)

Baker, Lindsay B; Ungaro, Corey T; Barnes, Kelly A; Nuccio, Ryan P; Reimel, Adam J; Stofan, John R

2014-01-01

Abstract This study compared a field versus reference laboratory technique for extracting (syringe vs. centrifuge) and analyzing sweat [Na(+)] and [K(+)] (compact Horiba B-722 and B-731, HORIBA vs. ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot-humid environment. Sweat samples were collected from seven anatomical sites on 30 athletes during 1-h cycling in a heat chamber (33°C, 67% rh). Ten minutes into exercise, skin was cleaned/dried and two sweat patches were applied per anatomical site. After removal, one patch per site was centrifuged and sweat was analyzed with HORIBA in the heat chamber (CENTRIFUGE HORIBA) versus HPLC (CENTRIFUGE HPLC). Sweat from the second patch per site was extracted using a 5-mL syringe and analyzed with HORIBA in the heat chamber (SYRINGE HORIBA) versus HPLC (SYRINGE HPLC). CENTRIFUGE HORIBA, SYRINGE HPLC, and SYRINGE HORIBA were highly related to CENTRIFUGE HPLC ([Na(+)]: ICC = 0.96, 0.94, and 0.93, respectively; [K(+)]: ICC = 0.87, 0.92, and 0.84, respectively), while mean differences from CENTRIFUGE HPLC were small but usually significant ([Na(+)]: 4.7 ± 7.9 mEql/L, -2.5 ± 9.3 mEq/L, 4.0 ± 10.9 mEq/L (all P CENTRIFUGE HPLC 95% of the time. The field (SYRINGE HORIBA) method of extracting and analyzing sweat from regional absorbent patches may be useful in obtaining sweat [Na(+)] when rapid estimates in a hot-humid field setting are needed.
Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot‐humid environment

Science.gov (United States)

Baker, Lindsay B.; Ungaro, Corey T.; Barnes, Kelly A.; Nuccio, Ryan P.; Reimel, Adam J.; Stofan, John R.

2014-01-01

Abstract This study compared a field versus reference laboratory technique for extracting (syringe vs. centrifuge) and analyzing sweat [Na+] and [K+] (compact Horiba B‐722 and B‐731, HORIBA vs. ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot‐humid environment. Sweat samples were collected from seven anatomical sites on 30 athletes during 1‐h cycling in a heat chamber (33°C, 67% rh). Ten minutes into exercise, skin was cleaned/dried and two sweat patches were applied per anatomical site. After removal, one patch per site was centrifuged and sweat was analyzed with HORIBA in the heat chamber (CENTRIFUGE HORIBA) versus HPLC (CENTRIFUGE HPLC). Sweat from the second patch per site was extracted using a 5‐mL syringe and analyzed with HORIBA in the heat chamber (SYRINGE HORIBA) versus HPLC (SYRINGE HPLC). CENTRIFUGE HORIBA, SYRINGE HPLC, and SYRINGE HORIBA were highly related to CENTRIFUGE HPLC ([Na+]: ICC = 0.96, 0.94, and 0.93, respectively; [K+]: ICC = 0.87, 0.92, and 0.84, respectively), while mean differences from CENTRIFUGE HPLC were small but usually significant ([Na+]: 4.7 ± 7.9 mEql/L, −2.5 ± 9.3 mEq/L, 4.0 ± 10.9 mEq/L (all P CENTRIFUGE HPLC 95% of the time. The field (SYRINGE HORIBA) method of extracting and analyzing sweat from regional absorbent patches may be useful in obtaining sweat [Na+] when rapid estimates in a hot‐humid field setting are needed. PMID:24793982
Challenges Facing Crop Production And (Some) Potential Solutions

Science.gov (United States)

Schnable, P. S.

2017-12-01

To overcome some of the myriad challenges facing sustainable crop production we are seeking to develop statistical models that will predict crop performance in diverse agronomic environments. Crop phenotypes such as yield and drought tolerance are controlled by genotype, environment (considered broadly) and their interaction (GxE). As a consequence of the next generation sequencing revolution genotyping data are now available for a wide diversity of accessions in each of the major crops. The necessary volumes of phenotypic data, however, remain limiting and our understanding of molecular basis of GxE is minimal. To address this limitation, we are collaborating with engineers to construct new sensors and robots to automatically collect large volumes of phenotypic data. Two types of high-throughput, high-resolution, field-based phenotyping systems and new sensors will be described. Some of these technologies will be introduced within the context of the Genomes to Fields Initiative. Progress towards developing predictive models will be briefly summarized. An administrative structure that fosters transdisciplinary collaborations will be briefly described.
The benefits of herbicide-resistant crops.

Science.gov (United States)

Green, Jerry M

2012-10-01

Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry.
What Governs Friction of Silicon Oxide in Humid Environment: Contact Area between Solids, Water Meniscus around the Contact, or Water Layer Structure?

Science.gov (United States)

Chen, Lei; Xiao, Chen; Yu, Bingjun; Kim, Seong H; Qian, Linmao

2017-09-26

In order to understand the interfacial parameters governing the friction force (F t ) between silicon oxide surfaces in humid environment, the sliding speed (v) and relative humidity (RH) dependences of F t were measured for a silica sphere (1 μm radius) sliding on a silicon oxide (SiO x ) surface, using atomic force microscopy (AFM), and analyzed with a mathematical model describing interfacial contacts under a dynamic condition. Generally, F t decreases logarithmically with increasing v to a cutoff value below which its dependence on interfacial chemistry and sliding condition is relatively weak. Above the cutoff value, the logarithmic v dependence could be divided into two regimes: (i) when RH is lower than 50%, F t is a function of both v and RH; (ii) in contrast, at RH ≥ 50%, F t is a function of v only, but not RH. These complicated v and RH dependences were hypothesized to originate from the structure of the water layer adsorbed on the surface and the water meniscus around the annulus of the contact area. This hypothesis was tested by analyzing F t as a function of the water meniscus area (A m ) and volume (V m ) estimated from a thermally activated water-bridge formation model. Surprisingly, it was found that F t varies linearly with V m and correlates poorly with A m at RH contact under ambient conditions.
Resilience of cereal crops to abiotic stress: A review

African Journals Online (AJOL)

SAM

2014-07-16

Jul 16, 2014 ... Key words: Cereal crops, abiotic stresses, food insecurity, molecular breeding, quantitative trait loci (QTLs), salinity, water stress. ... production of genetically modified (GM) crops, exo- genous use of osmo protectants etc. ... stressful environments is important to fulfill food demand of the ever-increasing world ...
Humidity-dependent phase state of SOA particles from biogenic and anthropogenic precursors

Directory of Open Access Journals (Sweden)

E. Saukko

2012-08-01

Full Text Available The physical phase state (solid, semi-solid, or liquid of secondary organic aerosol (SOA particles has important implications for a number of atmospheric processes. We report the phase state of SOA particles spanning a wide range of oxygen to carbon ratios (O / C, used here as a surrogate for SOA oxidation level, produced in a flow tube reactor by photo-oxidation of various atmospherically relevant surrogate anthropogenic and biogenic volatile organic compounds (VOCs. The phase state of laboratory-generated SOA was determined by the particle bounce behavior after inertial impaction on a polished steel substrate. The measured bounce fraction was evaluated as a function of relative humidity and SOA oxidation level (O / C measured by an Aerodyne high resolution time of flight aerosol mass spectrometer (HR-ToF AMS.

The main findings of the study are: (1 biogenic and anthropogenic SOA particles are found to be amorphous solid or semi-solid based on the measured bounced fraction (BF, which was typically higher than 0.6 on a 0 to 1 scale. A decrease in the BF is observed for most systems after the SOA is exposed to relative humidity of at least 80% RH, corresponding to a RH at impaction of 55%. (2 Long-chain alkanes have a low BF (indicating a "liquid-like", less viscous phase particles at low oxidation levels (BF < 0.2 ± 0.05 for O / C = 0.1. However, BF increases substantially upon increasing oxidation. (3 Increasing the concentration of sulphuric acid (H2sub>SO>4sub> in solid SOA particles (here tested for longifolene SOA causes a decrease in BF levels. (4 In the majority of cases the bounce behavior of the various SOA systems did not show correlation with the particle O / C. Rather, the molar mass of the gas-phase VOC precursor showed a positive correlation with the resistance to the RH-induced phase change of the formed SOA particles.
Development of Smart Ventilation Control Algorithms for Humidity Control in High-Performance Homes in Humid U.S. Climates

Energy Technology Data Exchange (ETDEWEB)

Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ticci, Sara [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-04-11

Past field research and simulation studies have shown that high performance homes experience elevated indoor humidity levels for substantial portions of the year in humid climates. This is largely the result of lower sensible cooling loads, which reduces the moisture removed by the cooling system. These elevated humidity levels lead to concerns about occupant comfort, health and building durability. Use of mechanical ventilation at rates specified in ASHRAE Standard 62.2-2013 are often cited as an additional contributor to humidity problems in these homes. Past research has explored solutions, including supplemental dehumidification, cooling system operational enhancements and ventilation system design (e.g., ERV, supply, exhaust, etc.). This project’s goal is to develop and demonstrate (through simulations) smart ventilation strategies that can contribute to humidity control in high performance homes. These strategies must maintain IAQ via equivalence with ASHRAE Standard 62.2-2013. To be acceptable they must not result in excessive energy use. Smart controls will be compared with dehumidifier energy and moisture performance. This work explores the development and performance of smart algorithms for control of mechanical ventilation systems, with the objective of reducing high humidity in modern high performance residences. Simulations of DOE Zero-Energy Ready homes were performed using the REGCAP simulation tool. Control strategies were developed and tested using the Residential Integrated Ventilation (RIVEC) controller, which tracks pollutant exposure in real-time and controls ventilation to provide an equivalent exposure on an annual basis to homes meeting ASHRAE 62.2-2013. RIVEC is used to increase or decrease the real-time ventilation rate to reduce moisture transport into the home or increase moisture removal. This approach was implemented for no-, one- and two-sensor strategies, paired with a variety of control approaches in six humid climates (Miami
SOIL ORGANIC CARBON FRACTIONS AS INFLUENCED BY SOYBEAN CROPPING IN THE HUMID PAMPA OF ARGENTINA

Directory of Open Access Journals (Sweden)

Marta E. Conti

2014-07-01

Full Text Available The sustainability of continuous cropping systems depends heavily on the years of intensive agricultural production and the choice of crop sequence that alters the fractions of soil organic matter. The aim of this study was to evaluate the impact of continuous soybean cultivation on fractions of organic carbon in the vertic Argiudolls of the Argentinean Pampas. Total organic carbon (TOC, particulate organic carbon (POC , fulvic acids (FA, humic acids (HA, humin (H and carbon produced by microbial respiration (Cresp were assessed in plots with continuous production of soybean for over 15 years (SP and grassland plots that were considered the change control (GP. A significant reduction of TOC and POC variables in cultured soybean SP plots, relative to grassland GP, was observed. The POC / TOC and Cresp / TOC ratios were significantly lower in soybean plots than in grasslands used as controls. These ratios were interpreted as a preferential tendency to maintain high rates of mineralization of labile carbon forms and increased biological stability of humified forms in cultured soybean plots. The shapes of the humic fractions of less complexity, FA and HA, were significantly reduced in the latter plots compared with grasslands, while no significant changes occurred in the more stable and recalcitrant forms of carbon, such as humin, in either plot type.
Sporulation of Metarhizium anisopliae var. Acridum and Beauveria bassiana on Rhammatocerus schistocercoides under humid and dry conditions

Directory of Open Access Journals (Sweden)

Magalhães Bonifácio Peixoto

2000-01-01

Full Text Available The sporulation of the fungi Metarhizium anisopliae var. acridum and Beauveria bassiana in cadavers of the grasshopper Rhammatocerus schistocercoides was studied in dry and humid environments. Both fungi were equally virulent against R. schistocercoides. However, internally, M. anisopliae produced more conidia than B. bassiana at 53% and 75% relative humidity. Externally, there was no sporulation at 53% and 75% RH, and M. anisopliae produced more conidia than B. bassiana at 100% RH.
Resistance of HEPA filter separator materials to humid air--hydrogen fluoride--fluorine environments

International Nuclear Information System (INIS)

Weber, C.W.; Petit, G.S.; Woodfin, S.B.

1977-01-01

The U. S. Energy Research and Development Administration (ERDA) is interested in the development of a high-efficiency particulate air (HEPA) filter that is resistant to such corrosive reagents as hydrogen fluoride (HF) and fluorine (F 2 ) in air environments of normal relative humidity (about 50% RH). Several types of separator materials are used in the fabrication of commercial filters. The basic types of separator materials are asbestos, Kraft paper, plastic, and aluminum. At the request of the ERDA Division of Operational Safety, the different types of separator materials have been evaluated for their resistance to corrosive attack by HF and F 2 . The separator materials were dynamically tested in the 4-stage multiunit tester located in the Oak Ridge Gaseous Diffusion Plant laboratories. This is the system previously used in the evaluation of the Herty Foundation filter paper samples. Concurrent with the testing of filter media for its resistance to HF and F 2 , another component of the completed filter, the separator, was tested. All samples were exposed to a constant air flow (50% RH) of 32 liters/min, at 100 0 F, containing 900 ppM HF and 300 ppM F 2 . Exposure periods varied from 2 to 1000 h; however, the longer exposures were made only on the stronger candidates. Test results show the plastic and aluminum separator materials to be superior to the other types in resistance to HF and F 2 . The asbestos separators disintegrated after a relatively short exposure time; the Kraft paper types were the next weakest. The Clear Plastic S was the best performer of the plastics tested
Humidity control device in a reactor container

International Nuclear Information System (INIS)

Aizawa, Motohiro; Igarashi, Hiroo; Osumi, Katsumi; Kimura, Takashi.

1986-01-01

Purpose: To provide a device capable of maintaining the inside of a container under high humidity circumstantial conditions causing less atmospheric corrosions, in order to prevent injuries due to atmospheric corrosions to smaller diameter stainless steel pipeways in the reactor container. Constitution: Stress corrosion cracks (SCC) to the smaller diameter stainless steel pipeways are caused dependent on the relative humidity and it is effective as the countermeasure against SCC to maintain the relative humidity at a low level less than 30 % or high level greater than 60 %. Based on the above findings, a humidity control device is disposed so as to maintain the relative humidity for the atmosphere within a reactor core on a higher humidity region. The device is adapted such that recycling gas in the dry-well coolant circuit is passed through an orifice to atomize the water introduced from feedwater pipe and introduce into a reactor core or such that the recycling gases in the dry-well cooling circuit are bubbled into water to remove chlorine gas in the reactor container gas thereby increasing the humidity in the reactor container. (Kamimura, M.)

Upper limits for air humidity based on human comfort

DEFF Research Database (Denmark)

Toftum, Jørn; Fanger, Povl Ole; Jørgensen, Anette S.

1998-01-01

respiratory cooling. Human subjects perceived the condition of their skin to be less acceptable with increasing skin humidity. Inhaled air was rated warmer, more stuffy and less acceptable with increasing air humidity and temperature. Based on the subjects' comfort responses, new upper limits for air humidity......The purpose of this study was to verify the hypothesis that insufficient respiratory cooling and a high level of skin humidity are two reasons for thermal discomfort at high air humidities, and to prescribe upper limits for humidity based on discomfort due to elevated skin humidity and insufficient...
Consideration in selecting crops for the human-rated life support system: a Linear Programming model

Science.gov (United States)

Wheeler, E. F.; Kossowski, J.; Goto, E.; Langhans, R. W.; White, G.; Albright, L. D.; Wilcox, D.; Henninger, D. L. (Principal Investigator)

1996-01-01

A Linear Programming model has been constructed which aids in selecting appropriate crops for CELSS (Controlled Environment Life Support System) food production. A team of Controlled Environment Agriculture (CEA) faculty, staff, graduate students and invited experts representing more than a dozen disciplines, provided a wide range of expertise in developing the model and the crop production program. The model incorporates nutritional content and controlled-environment based production yields of carefully chosen crops into a framework where a crop mix can be constructed to suit the astronauts' needs. The crew's nutritional requirements can be adequately satisfied with only a few crops (assuming vitamin mineral supplements are provided) but this will not be satisfactory from a culinary standpoint. This model is flexible enough that taste and variety driven food choices can be built into the model.
Magnetopriming - an alternate strategy for crop stress management of field crops

International Nuclear Information System (INIS)

Anand, Anjali

2014-01-01

Abiotic stresses are major deterrent to sustainable crop production worldwide. Seed germination and early seedling growth are considered as the most critical stages of plant growth under stress conditions. Maximising stress tolerance of crop species by breeding is an integral part of development of strategies for improving sustainable food production under stressed environment but the unprecedented rate at which stress is increasing vis-a-vis the time taken for development of a tolerant variety, necessitates exploring alternate strategies of crop stress management. Seed priming has emerged as a promising crop stress management technique that increases the speed of germination thus ensuring synchronized field emergence of the crop. Magnetopriming (exposure of seeds to magnetic field) is a non invasive physical stimulant used for improving seedling vigour that helps in establishment of crop stand under stress. In our experiments on maize; chickpea and wheat under water deficit and salinity, respectively, improved seed water absorption characteristics resulted in faster hydration of enzymes (amylases, protease and dehydrogenase) leading to early germination and enhanced vigour of seedlings under stress. Increased levels of hydrogen peroxide in faster germinating - magnetoprimed seeds, under both the growing conditions, suggested its role in oxidative signaling during seed germination process. An 'oxidative window' for reactive oxygen species ensured that faster germination rate in magnetoprimed seeds led to vigourous seedlings. Improved root system integrated with higher photosynthetic efficiency and efficient partitioning of Na + increased yield from magnetoprimed seeds under salinity in controlled experiments. Magnetopriming can be effectively used as a pre-sowing treatment for mitigating adverse effects of water deficit and salinity at seed germination and early seedling growth. Unlike other conventional priming techniques it avoids seed hydration and
Impact of Climate Change on Irrigation Demand and Crop Growth in a Mediterranean Environment of Turkey

Directory of Open Access Journals (Sweden)

Tomokazu Haraguchi

2007-10-01

Full Text Available A simulation study was carried out to describe effects of climate change on cropgrowth and irrigation water demand for a wheat-maize cropping sequence in aMediterranean environment of Turkey. Climate change scenarios were projected using dataof the three general circulation modelsÃ¢Â€Â”GCMs (CGCM2, ECHAM4 and MRIÃ¢Â€Â”for theperiod of 1990 to 2100 and one regional climate modelÃ¢Â€Â”RCMÃ¢Â€Â”for the period of 2070 to2079. Potential impacts of climate change based on GCMs data were estimated for the A2scenario in the Special Report on Emission Scenarios (SRES. The forcing data for theboundary condition of the RCM were given by the MRI model. Daily CGCM2 and RCMdata were used for computations of water balance and crop development. Predictionsderived from the models about changes in irrigation and crop growth in this study coveredthe period of 2070 to 2079 relative to the baseline period of 1994 to 2003. The effects ofclimate change on water demand and on wheat and maize yields were predicted using thedetailed crop growth subroutine of the SWAP (Soil-Water-Atmosphere-Plant model. Precipitation was projected to decrease by about 163, 163 and 105 mm during the periodof 1990 to 2100 under the A2 scenario of the CGCM2, ECHAM4 and MRI models,respectively. The CGCM2, ECHAM4 and MRI models projected a temperature rise of 4.3,5.3 and 3.1 oC, respectively by 2100. An increase in temperature may result in a higherevaporative demand of the atmosphere. However, actual evapotranspiration (ETa fromwheat cropland under a doubling CO2 concentration for the period of 2070 to 2079 wasSensors 2007, 7 2298 predicted to decrease by about 28 and 8% relative to the baseline period based on the CGCM2 and RCM data, respectively. According to these models, irrigation demand by wheat would be higher for the same period due to a decrease in precipitation. Both ETa and irrigation water for maize cropland were projected to decrease by 24 and 15
Effect of crop rotation on soil nutrient balance and weediness in soddy podzolic organic farming fields

Science.gov (United States)

Zarina, Livija; Zarina, Liga

2017-04-01

The nutrient balance in different crop rotations under organic cropping system has been investigated in Latvia at the Institute of Agricultural Resources and Economics since 2006. Latvia is located in a humid and moderate climatic region where the rainfall exceeds evaporation (soil moisture coefficient > 1) and the soil moisture regime is characteristic with percolation. The average annual precipitation is 670-850 mm. The average temperature varies from -6.7° C in January to 16.5 °C in July. The growing season is 175 - 185 days. The most widespread are podzolic soils and mainly they are present in agricultural fields in all regions of Latvia. In a wider sense the goal of the soil management in organic farming is a creation of the biologically active flora and fauna in the soil by maintaining a high level of soil organic matter which is good for crops nutrient balance. Crop rotation is a central component of organic farming systems and has many benefits, including growth of soil microbial activity, which may increase nutrient availability. The aim of the present study was to calculate nutrient balance for each crop in the rotations and average in each rotation. Taking into account that crop rotations can limit build-up of weeds, additionally within the ERA-net CORE Organic Plus transnational programs supported project PRODIVA the information required for a better utilization of crop diversification for weed management in North European organic arable cropping systems was summarized. It was found that the nutrient balance was influenced by nutrients uptake by biomass of growing crops in crop rotation. The number of weeds in the organic farming fields with crop rotation is dependent on the cultivated crops and the succession of crops in the crop rotation.
Decadal changes of reference crop evapotranspiration attribution: Spatial and temporal variability over China 1960-2011

Science.gov (United States)

Fan, Ze-Xin; Thomas, Axel

2018-05-01

Atmospheric evaporative demand can be used as a measure of the hydrological cycle and the global energy balance. Its long-term variation and the role of driving climatic factors have received increasingly attention in climate change studies. FAO-Penman-Monteith reference crop evapotranspiration rates were estimated for 644 meteorological stations over China for the period 1960-2011 to analyze spatial and temporal attribution variability. Attribution of climatic variables to reference crop evapotranspiration rates was not stable over the study period. While for all of China the contribution of sunshine duration remained relatively stable, the importance of relative humidity increased considerably during the last two decades, particularly in winter. Spatially distributed attribution analysis shows that the position of the center of maximum contribution of sunshine duration has shifted from Southeast to Northeast China while in West China the contribution of wind speed has decreased dramatically. In contrast relative humidity has become an important factor in most parts of China. Changes in the Asian Monsoon circulation may be responsible for altered patterns of cloudiness and a general decrease of wind speeds over China. The continuously low importance of temperature confirms that global warming does not necessarily lead to rising atmospheric evaporative demand.
A cost-effective and practical polybenzanthrone-based fluorescent sensor for efficient determination of palladium (II) ion and its application in agricultural crops and environment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ge [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Wen, Yangping [Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, and Key Laboratory of Physiology, Ecology and Cultivation of Double Cropping Rice, Ministry of Agriculture, Jiangxi Agricultural University, Nanchang 330045 (China); Guo, Chaoqun [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Xu, Jingkun, E-mail: xujingkun@tsinghua.org.cn [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Lu, Baoyang; Duan, Xuemin [Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); He, Haohua; Yang, Jun [Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, and Key Laboratory of Physiology, Ecology and Cultivation of Double Cropping Rice, Ministry of Agriculture, Jiangxi Agricultural University, Nanchang 330045 (China)

2013-12-17

Graphical abstract: -- Highlights: •PBA was facilely electrosynthesized in the binary solvent system containing of acetonitrile and boron trifluoride diethyl etherate. •“On–off” type fluorescent sensor based on this polymer for highly selective, sensitive, and practical detection of Pd{sup 2+} was designed. •The possible mechanism between Pd{sup 2+} and PBA has been discussed and TEM preliminary proved the proposed mechanism. •This fluorescent CP-based sensor has been used to practically detect Pd{sup 2+} in agricultural crops and environment samples with satisfactory results. -- Abstract: A highly selective and sensitive fluorescent chemosensor suitable for practical measurement of palladium ion (Pd{sup 2+}) in agricultural crops and environment samples has been successfully fabricated using polybenzanthrone (PBA). PBA was facilely electrosynthesized in the mixed electrolyte of acetonitrile and boron trifluoride diethyl etherate. The fluorescence intensity of PBA showed a linear response to Pd{sup 2+} in the concentration range of 5 nM–0.12 mM with a detection limit of 0.277 nM and quantification limit of 0.925 nM. Different compounds existing in agricultural crops and environment such as common metal ions, anions, natural amino acids, carbohydrates, and organic acids were used to examine the selectivity of the as-fabricated sensor, and no obvious fluorescence change could be observed in these interferents and their mixtures. A possible mechanism was proposed that the coordination of PBA and Pd{sup 2+} enhance the aggregation of polymer chains, which led to a significant quenching of PBA emission, and this was further confirmed by absorption spectra monitoring and transmission electron microscopy. The excellent performance of the proposed sensor and satisfactory results of the Pd{sup 2+} determination in practical samples suggested that the PBA-based fluorescent sensor for the determination of Pd{sup 2+} will be a good candidate for application in
Effect of air pollution on agricultural and forest crops. I

Energy Technology Data Exchange (ETDEWEB)

Matsushima, J

1971-10-01

Indirect and direct effects of air pollutants on agricultural and forest crops are discussed. Pollutants can cause changes in the quality of pesticides, imbalances in the nutritional makeup of crops, and other effects in the soil. Past studies have shown that there is a definite correlation between the germ induced blight of pine trees and the concentration of sulfur dioxide in air. Infestation of pine insects and the degree of oxidant in the air also have close relationships. The final cause for blight of pines is often the work of insects such as western pine beetles and mountain pine beetles, but the insects attack trees that are already weakened by oxidant. Orange trees sprayed with pesticide were fumigated in SO/sub 2/. Control trees showed a marked state of good health in comparison to the fumigated trees. However, the relationship and mechanism of the pesticide and SO/sub 2/ are controlled by a complex set of factors. Lime and sulfur compound pesticides also affect citrus trees when SO/sub 2/ is present. Trees sprayed during winter in conjunction with SO/sub 2/ fumigation show a heavy shedding of leaves. The SO/sub 2/ accumulation in soil and plant in the form of acidity or sulfur result in increases of potassium, calcium, or magnesium, depending on the type of produce. Direct effects of SO/sub 2/ are discussed based on the mathematical formula of Thomas, and invisible damages caused by winter fumigation in SO/sub 2/ such as deterioration of growth and photosynthesis are discussed.
Contribution of Crop Models to Adaptation in Wheat.

Science.gov (United States)

Chenu, Karine; Porter, John Roy; Martre, Pierre; Basso, Bruno; Chapman, Scott Cameron; Ewert, Frank; Bindi, Marco; Asseng, Senthold

2017-06-01

With world population growing quickly, agriculture needs to produce more with fewer inputs while being environmentally friendly. In a context of changing environments, crop models are useful tools to simulate crop yields. Wheat (Triticum spp.) crop models have been evolving since the 1960s to translate processes related to crop growth and development into mathematical equations. These have been used over decades for agronomic purposes, and have more recently incorporated advances in the modeling of environmental footprints, biotic constraints, trait and gene effects, climate change impact, and the upscaling of global change impacts. This review outlines the potential and limitations of modern wheat crop models in assisting agronomists, breeders, and policymakers to address the current and future challenges facing agriculture. Copyright © 2017 Elsevier Ltd. All rights reserved.
High Temperature Oxidation Behavior of T91 Steel in Dry and Humid Condition

Directory of Open Access Journals (Sweden)

Yonghao Leong

2016-09-01

Full Text Available High temperature oxidation behavior of T91 ferritic/martensitic steel was examined over the temperature range of 500 to 700°C in dry and humid environments. The weight gain result revealed that oxidation occurs at all range of temperatures and its rate is accelerated by increasing the temperature. The weight gain of the oxidized steel at 700°C in steam condition was six times bigger than the dry oxidation.. SEM/EDX of the cross-sectional image showed that under dry condition, a protective and steady growth of the chromium oxide (Cr2O3 layer was formed on the steel with the thickness of 2.39±0.34 µm. Meanwhile for the humid environment, it is found that the iron oxide layer, which consists of the hematite (Fe2O3 and magnetite (Fe3O4 was formed as the outer scale, and spinnel as inner scale. This result indicated that the oxidation behavior of T91 steel was affected by its oxidation environment. The existence of water vapor in steam condition may prevent the formation of chromium oxide as protective layer.
Wavelength properties of DCG holograms under the conditions of different temperature and humidity

Science.gov (United States)

Liu, Yujie; Li, Wenqiang; Ding, Quanxin; Yan, Zhanjun

2014-12-01

Holograms recorded in dichromated gelatin (DCG) are usually sealed with a glass plate cemented with an epoxy glue to protect the holograms from moisture in the environment. An investigation of the wavelength properties of sealed DCG holograms had been carried out paying attention to holograms which were exposed to different temperature and humidity environment in this work. The investigation had revealed that (a) exposing the sealed DCG holograms to high relative humidity (RH=98%) environment or immersing them in room-temperature water for 20 hours can not affect the holograms; (b) the sealed DCG holograms can be used at temperature below 50°C without showing undue detrimental effects regarding their optical properties; (c) the peak wavelength of sealed DCG holograms can cause blue shift of several nanometers at 70°C~85°C and the velocity of blue shift is proportional to the environmental temperature; (d) the holograms can be destroyed at 100° or above. The experimental results above will be analyzed and discussed in this paper. A method to improve the stability of sealed DCG holograms is proposed: baking the sealed DCG holograms at proper temperature (e.g., 85°C in this study).
Modelling nutrient management in tropical cropping systems

OpenAIRE

Delve, R. (ed.); Probert, M. (ed.)

2004-01-01

Metadata only record In tropical regions, organic materials are often more important than fertilizers in maintaining soil fertility, yet fertilizer recommendations and most crop models are unable to take account of the level and quality of organic inputs that farmers use. Computer simulation models, such as the Agricultural Production Systems Simulator (APSIM) developed by CSIRO and the Queensland Department of Primary Industries, have proven their value in many cropping environments. Thes...
Humidity and Buildings. Technical Paper No. 188.

Science.gov (United States)

Hutcheon, N. B.

Modified and controlled relative humidity in buildings for certain occupancies is discussed. New criteria are used in determining the needs, desirability and problems associated with humidities in a building. Severe winter climate requires that special attention be given to the problems associated with increased indoor humidities during cold…
Towards a CO{sub 2} neutral urban environment. Cutting the wire

Energy Technology Data Exchange (ETDEWEB)

Flarup Jensen, K.; Bentzen, B. (Faktor 3, Copenhagen (Denmark)); Poulsen, Peter; Dam-Hansen, C.; Thorseth, A.; Corell, D.D.; Stentoft Hansen, S. (Technical Univ. of Denmark, DTU Fotonik, Roskilde (Denmark)); Katic, I.; Poulsen, Soeren (Teknologisk Institut, Taastrup (Denmark))

2010-07-01

The outcome of the project ''TOWARDS A CO{sub 2} NEUTRAL URBAN ENVIRONMENT'' - cutting the wire has been: 1) Development of an advanced and flexible LED based artificial light source for testing solar cells and small panels under low light conditions (0-200 W/m2) and spectral variations in 400 nm - 1100 nm. 2) Development of hardware and software/user interface for electrical characterization of solar cells and panels by obtaining IV-curves and spectral response curves for solar cells and panels irradiated by the LED light source. 3) Develop and production of 10 advanced 100 nm spectrally resolved light logger units for stand-alone battery powered action for at least half a year in the addressed interval from 400 nm - 1100 nm. 4) Development of a stand-alone software tool and user interface for setup and data output of the data logger units. 5) Measuring the light condition at various spots for one whole year in two streets in Copenhagen. 6) Datahandling and comparison irradiation measurements with calculated and normalized data from solar simulation software and data from rooftop measurements at Danish Technological Institute and Danish Meteorological Institute. 7) Organization of a workshop for architects and city planners for who the results from this project should catalyze and lower the barriers for creating new or installing more solar powered applications in the urban environment. 8) Branding of the potential for saving energy and CO{sub 2}, cost of wirering and a lot of other secondary costs by using solar power as a source of energy directly where the need is in the urban environment. (Author)
Humidity Graphs for All Seasons.

Science.gov (United States)

Esmael, F.

1982-01-01

In a previous article in this journal (Vol. 17, p358, 1979), a wet-bulb depression table was recommended for two simple experiments to determine relative humidity. However, the use of a graph is suggested because it gives the relative humidity directly from the wet and dry bulb readings. (JN)
Humidity-dependent bacterial cells functional morphometry investigations using atomic force microscope.

Science.gov (United States)

Nikiyan, Hike; Vasilchenko, Alexey; Deryabin, Dmitry

2010-01-01

The effect of a relative humidity (RH) in a range of 93-65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties of B. cereus are rather stable in wide range of relative humidity, whereas E. coli are more sensitive to drying, significantly increasing roughness and stiffness parameters at RH
Humidity-Dependent Bacterial Cells Functional Morphometry Investigations Using Atomic Force Microscope

Directory of Open Access Journals (Sweden)

Hike Nikiyan

2010-01-01

Full Text Available The effect of a relative humidity (RH in a range of 93–65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties of B. cereus are rather stable in wide range of relative humidity, whereas E. coli are more sensitive to drying, significantly increasing roughness and stiffness parameters at RH ≤ 84% RH. It is discussed the dependence of the response features on differences in cell wall structure of gram-positive and gram-negative bacterial cells.
Statistical modeling reveals the effect of absolute humidity on dengue in Singapore.

Directory of Open Access Journals (Sweden)

Hai-Yan Xu

2014-05-01

Full Text Available Weather factors are widely studied for their effects on indicating dengue incidence trends. However, these studies have been limited due to the complex epidemiology of dengue, which involves dynamic interplay of multiple factors such as herd immunity within a population, distinct serotypes of the virus, environmental factors and intervention programs. In this study, we investigate the impact of weather factors on dengue in Singapore, considering the disease epidemiology and profile of virus serotypes. A Poisson regression combined with Distributed Lag Non-linear Model (DLNM was used to evaluate and compare the impact of weekly Absolute Humidity (AH and other weather factors (mean temperature, minimum temperature, maximum temperature, rainfall, relative humidity and wind speed on dengue incidence from 2001 to 2009. The same analysis was also performed on three sub-periods, defined by predominant circulating serotypes. The performance of DLNM regression models were then evaluated through the Akaike's Information Criterion. From the correlation and DLNM regression modeling analyses of the studied period, AH was found to be a better predictor for modeling dengue incidence than the other unique weather variables. Whilst mean temperature (MeanT also showed significant correlation with dengue incidence, the relationship between AH or MeanT and dengue incidence, however, varied in the three sub-periods. Our results showed that AH had a more stable impact on dengue incidence than temperature when virological factors were taken into consideration. AH appeared to be the most consistent factor in modeling dengue incidence in Singapore. Considering the changes in dominant serotypes, the improvements in vector control programs and the inconsistent weather patterns observed in the sub-periods, the impact of weather on dengue is modulated by these other factors. Future studies on the impact of climate change on dengue need to take all the other contributing
Statistical modeling reveals the effect of absolute humidity on dengue in Singapore.

Science.gov (United States)

Xu, Hai-Yan; Fu, Xiuju; Lee, Lionel Kim Hock; Ma, Stefan; Goh, Kee Tai; Wong, Jiancheng; Habibullah, Mohamed Salahuddin; Lee, Gary Kee Khoon; Lim, Tian Kuay; Tambyah, Paul Anantharajah; Lim, Chin Leong; Ng, Lee Ching

2014-05-01

Weather factors are widely studied for their effects on indicating dengue incidence trends. However, these studies have been limited due to the complex epidemiology of dengue, which involves dynamic interplay of multiple factors such as herd immunity within a population, distinct serotypes of the virus, environmental factors and intervention programs. In this study, we investigate the impact of weather factors on dengue in Singapore, considering the disease epidemiology and profile of virus serotypes. A Poisson regression combined with Distributed Lag Non-linear Model (DLNM) was used to evaluate and compare the impact of weekly Absolute Humidity (AH) and other weather factors (mean temperature, minimum temperature, maximum temperature, rainfall, relative humidity and wind speed) on dengue incidence from 2001 to 2009. The same analysis was also performed on three sub-periods, defined by predominant circulating serotypes. The performance of DLNM regression models were then evaluated through the Akaike's Information Criterion. From the correlation and DLNM regression modeling analyses of the studied period, AH was found to be a better predictor for modeling dengue incidence than the other unique weather variables. Whilst mean temperature (MeanT) also showed significant correlation with dengue incidence, the relationship between AH or MeanT and dengue incidence, however, varied in the three sub-periods. Our results showed that AH had a more stable impact on dengue incidence than temperature when virological factors were taken into consideration. AH appeared to be the most consistent factor in modeling dengue incidence in Singapore. Considering the changes in dominant serotypes, the improvements in vector control programs and the inconsistent weather patterns observed in the sub-periods, the impact of weather on dengue is modulated by these other factors. Future studies on the impact of climate change on dengue need to take all the other contributing factors into
Improvement of red pepper yield and soil environment by summer catch aquatic crops in greenhouses

Science.gov (United States)

Du, X. F.; Wang, L. Z.; Peng, J.; Wang, G. L.; Guo, X. S.; Wen, T. G.; Gu, D. L.; Wang, W. Z.; Wu, C. W.

2016-08-01

To investigate effects of the rotation of summer catch crops on remediation retrogressed soils in continuous cropping, a field experiment was conducted. Rice, water spinach, or cress were selected as summer catch crops; bare fallow during summer fallow was used as the control group. Results showed that aquatic crops grown in summer fallow period could effectively reduce soil bulk density and pH, facilitate soil nutrient release, and improve soil physical and chemical properties compared with those grown in fallow period. Paddy-upland rotation could improve soil microbial members and increase bacterial and actinomycete populations; by contrast, paddy-upland rotation could reduce fungal populations and enhance bacterium-to-fungus ratio. Paddy-upland rotation could also actively promote activities of soil enzymes, such as urease, phosphatase, invertase, and catalase. The proposed paddy-upland rotation significantly affected the growth of red pepper; the yield and quality of the grown red pepper were enhanced. Summer catch crops, such as rice, water spinach, and cress significantly increased pepper yield in the following growing season by 15.4%, 10.2% and 14.0%, respectively, compared with those grown in fallow treatment. Therefore, the proposed paddy-upland crop rotation could be a useful method to alleviate continuous cropping problems involved in cultivating red pepper in greenhouses.

Degradation modes of austenitic and ferritic–martensitic stainless steels in He–CO–CO{sub 2} and liquid sodium environments of equivalent oxygen and carbon chemical potentials

Energy Technology Data Exchange (ETDEWEB)

Gulsoy, G., E-mail: gulsoy@umich.edu [Department of Materials Science and Engineering, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Was, G.S. [Department of Materials Science and Engineering, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109 (United States); Pawel, S.J.; Busby, J.T. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2013-10-15

The objective of this work is to explore possible thermodynamic correlations between the degradation modes of austenitic and ferritic–martensitic alloys observed in high temperature He–CO–CO{sub 2} environments with oxygen and carbon chemical potentials equivalent to that in a liquid sodium environment containing 2–5 molppm oxygen and 0.02–0.2 molppm carbon at temperatures 500–700 °C. Two He–CO–CO{sub 2} environments (Pco/Pco{sub 2} = 1320, Pco = 1980 molppm, and Pco/Pco{sub 2} = 9, Pco = 13.5 molppm) were selected to test alloys NF616 and 316L at 700 and 850 °C. Upon exposure to He environments at 850 °C, 316L samples exhibited thick surface Cr{sub 2}O{sub 3} scales and substantial internal oxidation; however at 700 °C no significant internal oxidation was observed. NF616 samples exhibited relatively thinner surface Cr{sub 2}O{sub 3} scales compared to 316L samples at both temperatures. NF616 samples exposed to liquid sodium at 700 °C and He–Pco/Pco{sub 2} = 9 at 850 °C showed decarburization. No surface oxide formation was observed on the sample exposed to the Na environment. Results obtained from He exposure experiments provide insight into what may occur during long exposure times in a sodium environment.
MnO{sub 2}-protected silver nanoparticles: New electromagnetic nanoresonators for Raman analysis of surfaces in basis environment

Energy Technology Data Exchange (ETDEWEB)

Abdulrahman, Heman Burhanalden; Kołątaj, Karol; Lenczewski, Paweł; Krajczewski, Jan; Kudelski, Andrzej, E-mail: akudel@chem.uw.edu.pl

2016-12-01

Graphical abstract: - Highlights: • New nanoresonators for Raman surface analysis in basis environment were fabricated. • The new nanoresonators for SHINERS experiments are significantly more efficient. • The first example of synthesis of Ag@MnO{sub 2} nanoparticles is reported. - Abstract: The first example of the synthesis of Ag nanoparticles protected by a few nanometers thick layer of MnO{sub 2} (Ag@MnO{sub 2}) has been reported. Synthesized Ag@MnO{sub 2} nanoparticles effectively locally enhance the electric field of the incident visible radiation, which allows, for example, for a large enhancement of the efficiency of Raman scattering for species located in the close proximity to such nanostructures. It means that Ag@MnO{sub 2} nanoparticles may be used as nanoresonators for shell-isolated nanoparticle-enhanced Raman scattering (SHINERS) measurements. The obtained Ag@MnO{sub 2} nanoparticles are almost two orders of magnitude more efficient in enhancing Raman signal than previously used for SHINERS measurements in the alkali environment Au@MnO{sub 2} nanostructures. Moreover, in comparison to Ag@SiO{sub 2} nanoparticles, which are standard silver nanoresonators for SHINERS experiments, Ag@MnO{sub 2} nanoparticles are significantly more stable in the basic conditions. Deposition of the MnO{sub 2} layer (by the reduction of KMnO{sub 4} with by K{sub 2}C{sub 2}O{sub 4} in an alkaline condition) on hollow silver nanoparticles (h-Ag) has been also analyzed. Hollow silver shells are significantly less stable than the solid Ag nanostructures and are practically entirely destroyed during the process of the MnO{sub 2} deposition. However, in this condition, the majority of h-Ag nanoparticles form agglomerates containing about 10{sup 1} h-Ag items which are connected by MnO{sub 2}, and after dissolution of the silver auxiliary templates very regular MnO{sub 2} sponge nanostructures with the diameter of 150–300 nm are formed.
Operando X-ray diffraction analysis for a glyme-based Li-O{sub 2} battery

Energy Technology Data Exchange (ETDEWEB)

Yogi, C.; Takao, N.; Kubobuchi, K.; Matsumoto, M.; Mogi, M., E-mail: mogi@nissan-arc.co.jp; Imai, H. [Device-functional analysis department, NISSAN ARC Ltd., 1 Natsushima, Yokosuka Kanagawa, 237-0061 JAPAN (Japan); Watanabe, T. [Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Koto, Sayo Hyogo, 679-5198 JAPAN (Japan)

2016-08-26

We investigated the effect of the carbon species in the air (oxygen) electrode, electrolyte concentration, and humidity in the supplied O{sub 2} gas on the Li-O{sub 2} reactions by using the operando XRD analysis. Regarding carbon species, we found that the over-potentials in the galvanostatic discharge-charge process were suppressed when using the KB carbon in the air electrode. The results of operando XRD measurements revealed that the Li{sub 2}O{sub 2} formed on the KB had the smaller crystalline or more amorphous like structures, which could be one reason for faster reaction kinetics of Li{sub 2}O{sub 2} dissolution. The discharge-charge curves of the cells with different concentration of LiTFSI/(G4){sub n} electrolyte showed the slight difference but less differences in the Li{sub 2}O{sub 2} formation and dissolution behaviors. In addition to the nature of Li{sub 2}O{sub 2} products, reaction of Li-salts would also have ineligible effects. We also found that the higher humidity in oxygen produced more the LiOH and promoted the Li{sub 2}O{sub 2} dissolution, which indicate that the LiOH formation could affect the Li{sub 2}O{sub 2} morphologies or surface chemistries. Our present results demonstrated that the operando XRD measurement are useful for analyzing the reaction mechanism of Li-O{sub 2} battery.
Effects of Dy{sub 71.5}Fe{sub 28.5} intergranular addition on the microstructure and the corrosion resistance of Nd–Fe–B sintered magnets

Energy Technology Data Exchange (ETDEWEB)

Liang, Liping; Ma, Tianyu, E-mail: maty@zju.edu.cn; Zhang, Pei; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

2015-06-15

To satisfy high-temperature applications, heavy rare-earth (RE) Dy is commonly introduced into the Nd–Fe–B sintered magnets to improve the coercivity. In addition to forming (Nd, Dy){sub 2}Fe{sub 14}B, Dy also exists in the intergranular RE-rich phase. Hence, understanding the effect of Dy on the electrochemical characteristics of the RE-rich phase and corrosion resistance of the magnet is of importance. In this work, eutectic alloy Dy{sub 71.5}Fe{sub 28.5} powders were added into the (Pr{sub 0.2}Nd{sub 0.8}){sub 12.3}Fe{sub bal}B{sub 6.1} magnet through binary-alloy approach to investigate the corrosion resistance of the magnet in electrochemical and hot/humid environments. The results demonstrate that Dy is enriched in the intergranular phase, improving its electrode potential and stability due to the higher electrode potential of Dy than Nd or Pr. As a consequence, the electrode potential difference between the 2:14:1 phase and the RE-rich phase is reduced, improving the corrosion resistance. Furthermore, formation of (Pr, Nd, Dy){sub 2}Fe{sub 14}B shell with stronger local anisotropy surrounding the 2:14:1 phase grains improves the coercivity with a slight remanence loss. Therefore, intergranular adding Dy–Fe alloy powders can obtain both high magnetic properties and good corrosion resistance simultaneously. - Highlights: • Eutectic Dy{sub 71.5}Fe{sub 28.5} powders were intergranular added to NdFeB sintered magnets. • The doped magnet showed improved corrosion resistance compared to Dy-free magnet. • Dy enrichment in RE-rich intergranular phase improved its electrode potential. • (Nd, Dy){sub 2}Fe{sub 14}B shell was expected to form in the surface of Nd{sub 2}Fe{sub 14}B grains. • Both corrosion resistance and coercivity were improved in Dy–Fe doped magnet.
XAS study of the local environment of impurities in doped TiO{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Torres, C.E. [Departamento de Fisica e IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina)]. E-mail: torres@fisica.unlp.edu.ar; Cabrera, A.F. [Departamento de Fisica e IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Errico, L.A. [Departamento de Fisica e IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Duhalde, S. [Lab. de Ablacion Laser, FI-UBA (Argentina); Renteria, M. [Departamento de Fisica e IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Golmar, F. [Lab. de Ablacion Laser, FI-UBA (Argentina); Sanchez, F.H. [Departamento de Fisica e IFLP (CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina)

2007-09-01

In this work, we present an X-ray absorption spectroscopy (XAS) characterization of the local environment of the impurity in room temperature ferromagnetic (RTF) anatase TiO{sub 2} thin films doped with Co, Ni, Cu, or Zn, deposited on LaAlO{sub 3} substrate by pulsed laser deposition (PLD). It was found that there is a considerable amount of impurity atoms substituting Ti in TiO{sub 2} anatase, although the presence of metal transition monoxide clusters can not be discarded. From our results, we infer that the observed RT ferromagnetism of the samples could be assigned to the metal transition atoms replacing Ti in TiO{sub 2} anatase.
Stress corrosion cracking of U-0.1% Cr in humid helium atmosphere

International Nuclear Information System (INIS)

Zalkind, S.; Eshkenazy, R.; Harush, S.; Halperin, D.; Moreno, D.; Abramov, E.; Venkert, A.

1994-01-01

Rivets were matched into adapted drilled holes in plates, both made of U-0.1% Cr alloy and were placed in different environments containing dry air and helium and humid air and helium for a variety of exposure times. After opening, the most significant amounts of corrosion products were detected in the specimens that stayed for three years in humid helium (5% RH) environment. Radial cracks, developed in the bore edge, were detected in the specimens. X-ray diffraction patterns of the corrosion products gave the composition of UH 3 and UO 2 . The microstructure was examined using light and electron microscopy techniques. The hydride phase that was observed, formed mainly beneath the oxide layer and penetrated into the metal matrix as needle-like forms. The formation of a lower density hydride phase, yielded in a large volume change causing the development of high stresses at the rivet-bore interface. The combination of the high stress and the weakening of the bore edge due to the presence of the brittle hydride phase led to radial crack formation around the bore edge. (orig.)
Agroecology and healthy food systems in semi-humid tropical Africa: Participatory research with vulnerable farming households in Malawi.

Science.gov (United States)

Nyantakyi-Frimpong, Hanson; Kangmennaang, Joseph; Bezner Kerr, Rachel; Luginaah, Isaac; Dakishoni, Laifolo; Lupafya, Esther; Shumba, Lizzie; Katundu, Mangani

2017-11-01

This paper assesses the relationship between agroecology, food security, and human health. Specifically, we ask if agroecology can lead to improved food security and human health among vulnerable smallholder farmers in semi-humid tropical Africa. The empirical evidence comes from a cross-sectional household survey (n=1000) in two districts in Malawi, a small country in semi-humid, tropical Africa. The survey consisted of 571 agroecology-adoption and 429 non-agroecology-adoption households. Ordered logistics regression and average treatment effects models were used to determine the effect of agroecology adoption on self-reported health. Our results show that agroecology-adoption households (OR=1.37, p=0.05) were more likely to report optimal health status, and the average treatment effect shows that adopters were 12% more likely to be in optimal health. Furthermore, being moderately food insecure (OR=0.59, p=0.05) and severely food insecure (OR=0.89, p=0.10) were associated with less likelihood of reporting optimal health status. The paper concludes that with the adoption of agroecology in the semi-humid tropics, it is possible for households to diversify their crops and diets, a condition that has strong implications for improved food security, good nutrition and human health. Copyright © 2016 Elsevier B.V. All rights reserved.
Crop yield response to water stress imposed at different growth stages

International Nuclear Information System (INIS)

Iqbal, M.; Mahmood Shah, M.; Wisal, M.

1995-01-01

Potato requires sufficient soil moisture and fertilization to produce high yields but the present water resoures are limited compared to the cultivable land, field experiments were conduced from 1991 to 1995 to study relationship between yield and crop water use as a function of water stress imposed at different growth stages. The irrigation treatments involved application of full and stress watering s selectively at four growth stages : Establishment , Flowering Tuber formation and ripening. In full watering, full water requirements of the crop were met, i.e., ET sub a = ET sub m whereas in stress watering about half the amount of full watering was applied, i.e., ET sub a < ET sub m. Changes in moisture content of the soil pre files after irrigation were monitored with the help of neutron moisture probe in order to compute ET sub a by the water balance method. The results obtained showed that the tuber yield was produced by full watering ( T 1) and the lowest by continuous stress watering (T 2). A plot of relative yield against relative evapotranspiration deficit revealed that ripening was the lest sensitive whereas early development followed by flowering the most sensitive growth stage to water stress. The crop water use efficiencies were generally higher in the treatments where a combination of normal and stress watering was applied compared to where all - normal watering s were applied. The traditional irrigation practice resulted in wasteful water application with relatively lower yields, hence the results from this project will have high value for the farming community to get this higher yields with scarce water resources. The studies with labelled fertilizer showed that planting and earthing - up were equally important growth stages of potato for applying fertilizer for its efficient utilization. 3 figs; 25 tabs; 12 refs (Author)
Humid Heat Waves at different warming levels

Science.gov (United States)

Russo, S.; Sillmann, J.; Sterl, A.

2017-12-01

The co-occurrence of consecutive hot and humid days during a heat wave can strongly affect human health. Here, we quantify humid heat wave hazard in the recent past and at different levels of global warming.We find that the magnitude and apparent temperature peak of heat waves, such as the ones observed in Chicago in 1995 and China in 2003, have been strongly amplified by humidity. Climate model projections suggest that the percentage of area where heat wave magnitude and peak are amplified by humidity increases with increasing warming levels. Considering the effect of humidity at 1.5o and 2o global warming, highly populated regions, such as the Eastern US and China, could experience heat waves with magnitude greater than the one in Russia in 2010 (the most severe of the present era).The apparent temperature peak during such humid-heat waves can be greater than 55o. According to the US Weather Service, at this temperature humans are very likely to suffer from heat strokes. Humid-heat waves with these conditions were never exceeded in the present climate, but are expected to occur every other year at 4o global warming. This calls for respective adaptation measures in some key regions of the world along with international climate change mitigation efforts.
7 CFR 28.301 - Measurement: humidity; temperature.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Measurement: humidity; temperature. 28.301 Section 28... for Length of Staple § 28.301 Measurement: humidity; temperature. The length of staple of any cotton... its fibers under a relative humidity of the atmosphere of 65 percent and a temperature of 70° F. ...
Improving stomatal functioning at elevated growth air humidity: A review.

Science.gov (United States)

Fanourakis, Dimitrios; Bouranis, Dimitrios; Giday, Habtamu; Carvalho, Dália R A; Rezaei Nejad, Abdolhossein; Ottosen, Carl-Otto

2016-12-01

Plants grown at high relative air humidity (RH≥85%) are prone to lethal wilting upon transfer to conditions of high evaporative demand. The reduced survival of these plants is related to (i) increased cuticular permeability, (ii) changed anatomical features (i.e., longer pore length and higher stomatal density), (iii) reduced rehydration ability, (iv) impaired water potential sensitivity to leaf dehydration and, most importantly, (v) compromised stomatal closing ability. This review presents a critical analysis of the strategies which stimulate stomatal functioning during plant development at high RH. These include (a) breeding for tolerant cultivars, (b) interventions with respect to the belowground environment (i.e., water deficit, increased salinity, nutrient culture and grafting) as well as (c) manipulation of the aerial environment [i.e., increased proportion of blue light, increased air movement, temporal temperature rise, and spraying with abscisic acid (ABA)]. Root hypoxia, mechanical disturbance, as well as spraying with compounds mimicking ABA, lessening its inactivation or stimulating its within-leaf redistribution are also expected to improve stomatal functioning of leaves expanded in humid air. Available evidence leaves little doubt that genotypic and phenotypic differences in stomatal functioning following cultivation at high RH are realized through the intermediacy of ABA. Copyright Â© 2016 Elsevier GmbH. All rights reserved.
Quantifying the Impact of Tropospheric Ozone on Crops Productivity at regional scale using JULES-crop

Science.gov (United States)

Leung, F.

2016-12-01

Tropospheric ozone (O3) is the third most important anthropogenic greenhouse gas. It is causing significant crop production losses. Currently, O3 concentrations are projected to increase globally, which could have a significant impact on food security. The Joint UK Land Environment Simulator modified to include crops (JULES-crop) is used here to quantify the impacts of tropospheric O3 on crop production at the regional scale until 2100. We evaluate JULES-crop against the Soybean Free-Air-Concentration-Enrichment (SoyFACE) experiment in Illinois, USA. Experimental data from SoyFACE and various literature sources is used to calibrate the parameters for soybean and ozone damage parameters in soybean in JULES-crop. The calibrated model is then applied for a transient factorial set of JULES-crop simulations over 1960-2005. Simulated yield changes are attributed to individual environmental drivers, CO2, O3 and climate change, across regions and for different crops. A mixed scenario of RCP 2.6 and RCP 8.5 climatology and ozone are simulated to explore the implication of policy. The overall findings are that regions with high ozone concentration such as China and India suffer the most from ozone damage, soybean is more sensitive to O3 than other crops. JULES-crop predicts CO2 fertilisation would increase the productivity of vegetation. This effect, however, is masked by the negative impacts of tropospheric O3. Using data from FAO and JULES-crop estimated that ozone damage cost around 55.4 Billion USD per year on soybean. Irrigation improves the simulation of rice only, and it increases the relative ozone damage because drought can reduce the ozone from entering the plant stomata. RCP 8.5 scenario results in a high yield for all crops mainly due to the CO2 fertilisation effect. Mixed climate scenarios simulations suggest that RCP 8.5 CO2 concentration and RCP 2.6 O3 concentration result in the highest yield. Further works such as more crop FACE-O3 experiments and more Crop
Rapid fabrication of superhydrophobic Al/Fe{sub 2}O{sub 3} nanothermite film with excellent energy-release characteristics and long-term storage stability

Energy Technology Data Exchange (ETDEWEB)

Ke, Xiang; Zhou, Xiang, E-mail: zhouxiang@njust.edu.cn; Hao, Gaozi; Xiao, Lei; Liu, Jie; Jiang, Wei, E-mail: superfine_jw@126.com

2017-06-15

natural aging test and 60.5% in accelerated aging test. This study is instructive to the practical applications of nanothermites, especially in highly humid environment.
Finger Millet: A “Certain” Crop for an “Uncertain” Future and a Solution to Food Insecurity and Hidden Hunger under Stressful Environments

Science.gov (United States)

Gupta, Sanjay Mohan; Arora, Sandeep; Mirza, Neelofar; Pande, Anjali; Lata, Charu; Puranik, Swati; Kumar, J.; Kumar, Anil

2017-01-01

Crop growth and productivity has largely been vulnerable to various abiotic and biotic stresses that are only set to be compounded due to global climate change. Therefore developing improved varieties and designing newer approaches for crop improvement against stress tolerance have become a priority now-a-days. However, most of the crop improvement strategies are directed toward staple cereals such as rice, wheat, maize etc., whereas attention on minor cereals such as finger millet [Eleusine coracana (L.) Gaertn.] lags far behind. It is an important staple in several semi-arid and tropical regions of the world with excellent nutraceutical properties as well as ensuring food security in these areas even during harsh environment. This review highlights the importance of finger millet as a model nutraceutical crop. Progress and prospects in genetic manipulation for the development of abiotic and biotic stress tolerant varieties is also discussed. Although limited studies have been conducted for genetic improvement of finger millets, its nutritional significance in providing minerals, calories and protein makes it an ideal model for nutrition-agriculture research. Therefore, improved genetic manipulation of finger millets for resistance to both abiotic and biotic stresses, as well as for enhancing nutrient content will be very effective in millet improvement. Key message: Apart from the excellent nutraceutical value of finger millet, its ability to tolerate various abiotic stresses and resist pathogens make it an excellent model for exploring vast genetic and genomic potential of this crop, which provide us a wide choice for developing strategies for making climate resilient staple crops. PMID:28487720
Finger Millet: A “Certain” Crop for an “Uncertain” Future and a Solution to Food Insecurity and Hidden Hunger under Stressful Environments

Directory of Open Access Journals (Sweden)

Anil Kumar

2017-04-01

Full Text Available Crop growth and productivity has largely been vulnerable to various abiotic and biotic stresses that are only set to be compounded due to global climate change. Therefore developing improved varieties and designing newer approaches for crop improvement against stress tolerance have become a priority now-a-days. However, most of the crop improvement strategies are directed toward staple cereals such as rice, wheat, maize etc., whereas attention on minor cereals such as finger millet [Eleusine coracana (L. Gaertn.] lags far behind. It is an important staple in several semi-arid and tropical regions of the world with excellent nutraceutical properties as well as ensuring food security in these areas even during harsh environment. This review highlights the importance of finger millet as a model nutraceutical crop. Progress and prospects in genetic manipulation for the development of abiotic and biotic stress tolerant varieties is also discussed. Although limited studies have been conducted for genetic improvement of finger millets, its nutritional significance in providing minerals, calories and protein makes it an ideal model for nutrition-agriculture research. Therefore, improved genetic manipulation of finger millets for resistance to both abiotic and biotic stresses, as well as for enhancing nutrient content will be very effective in millet improvement.Key message: Apart from the excellent nutraceutical value of finger millet, its ability to tolerate various abiotic stresses and resist pathogens make it an excellent model for exploring vast genetic and genomic potential of this crop, which provide us a wide choice for developing strategies for making climate resilient staple crops.
Effect of the temperature and relative humidity in dosemeters used for personnel monitoring

International Nuclear Information System (INIS)

Antonio Filho, J.

1982-12-01

The systematics of the combined effect of temperature and humidity on photographic dosimeters of the type Agfa-Gevaert, Kodak type II, III and the thermoluminescent dosimeters LiF:Mg,Ti (TLD-100, Harshaw), D-CaSO 4 :Dy-0,4 (Teledyne), e CaSO 4 :Dy+NaCl (IPEN), used in personal monitoring in Brazil was investigated, in the temperature range of 20 0 C to 50 0 C and relative humidity of 65% to 95%, in order to determine the best manner of utilization of these detectors in Brazilian climatic conditions. The dosimeters were studied in different forms of packing-sheet such as aluminezed paper and polyethylene. For the determination of the systematics, the dosimeters were irradiated in three conditions: before, during and after of storage in climatic chambers to a maximum period of 60 days. It was found that the dosimetric filmes and thermoluminescent dosimeter CaSO 4 :Dy+NaCl without protection, presented a high dependence to temperature and humidity, and when protected presented good results. Therefore, the best manner of utilization of these monitors in environments with relative humidity and temperature greater them 75% and 30 0 C respectively, is achieved with the protection of aluminized paper. The LiF:Mg,Ti and D+CaSO 4 :Dy-0,4 dosimeters can be utilized in their original form because they presented low dependence with humidity and temperature in the range studied. (Author) [pt
Humidity detection using chitosan film based sensor

Science.gov (United States)

Nasution, T. I.; Nainggolan, I.; Dalimunthe, D.; Balyan, M.; Cuana, R.; Khanifah, S.

2018-02-01

A humidity sensor made of the natural polymer chitosan has been successfully fabricated in the film form by a solution casting method. Humidity testing was performed by placing a chitosan film sensor in a cooling machine room, model KT-2000 Ahu. The testing results showed that the output voltage values of chitosan film sensor increased with the increase in humidity percentage. For the increase in humidity percentage from 30 to 90% showed that the output voltage of chitosan film sensor increased from 32.19 to 138.75 mV. It was also found that the sensor evidenced good repeatability and stability during the testing. Therefore, chitosan has a great potential to be used as new sensing material for the humidity detection of which was cheaper and environmentally friendly.
Les principaux ravageurs des choux pommés [Brassica oleracea var capitata subs sabouda à Bukavu et ses environs

Directory of Open Access Journals (Sweden)

Walangululu, JM.

2000-01-01

Full Text Available The Major Pests of Cabbage (Brassica oleracea var. capitata subs sabouda in Bukavu and Around. As stated by farmers growing vegetables and as observed on local markets, cabbage in Bukavu and around is damaged by pests. The present work was intended to identify pests damaging this crop, which is now a cash crop in this region, in order to design control methods. Results revealed that one aphid species (Brevicoryne brassicaej, the common cutworm (Agrotis segetum and some Caterpillar species (Plutella xylostella, Hellula undalis, Spodoptera exempta and Trichoplusia ni are major pests causing a loss of plantlets estimated from 0 to 53.8 %, mainly one month after planting. Damage on the first five leaves of the head of cabbage, estimated from 3.5 to 55.8 % of plants were attributed to sporadic pests as the tobacco cricket (Brachytrupes mem-branaceus, the common cutworm (Agrotis segetum, chickens, some grasshoppers, snails and a tortoise beetle species (Henosepilachna elateris.
Nitrogen effects on maize yield following groundnut in rotation on ...

African Journals Online (AJOL)

Rotating maize (Zea mays L.) with groundnut (Arachis hypogaea L.) has been proposed as a way to maintain soil fertility and prevent maize productivity declines in the smallholder cropping systems of sub-humid Zimbabwe. Field experiments with fertilizer-N on maize in rotation with groundnut were conducted at three ...
Biodiversity, evolution and adaptation of cultivated crops.

Science.gov (United States)

Vigouroux, Yves; Barnaud, Adeline; Scarcelli, Nora; Thuillet, Anne-Céline

2011-05-01

The human diet depends on very few crops. Current diversity in these crops is the result of a long interaction between farmers and cultivated plants, and their environment. Man largely shaped crop biodiversity from the domestication period 12,000 B.P. to the development of improved varieties during the last century. We illustrate this process through a detailed analysis of the domestication and early diffusion of maize. In smallholder agricultural systems, farmers still have a major impact on crop diversity today. We review several examples of the major impact of man on current diversity. Finally, biodiversity is considered to be an asset for adaptation to current environmental changes. We describe the evolution of pearl millet in West Africa, where average rainfall has decreased over the last forty years. Diversity in cultivated varieties has certainly helped this crop to adapt to climate variation. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

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