WorldWideScience

Sample records for air dried soil

  1. Dry deposition and soil-air gas exchange of polychlorinated biphenyls (PCBs) in an industrial area.

    Science.gov (United States)

    Bozlaker, Ayse; Odabasi, Mustafa; Muezzinoglu, Aysen

    2008-12-01

    Ambient air and dry deposition, and soil samples were collected at the Aliaga industrial site in Izmir, Turkey. Atmospheric total (particle+gas) Sigma(41)-PCB concentrations were higher in summer (3370+/-1617 pg m(-3), average+SD) than in winter (1164+/-618 pg m(-3)), probably due to increased volatilization with temperature. Average particulate Sigma(41)-PCBs dry deposition fluxes were 349+/-183 and 469+/-328 ng m(-2) day(-1) in summer and winter, respectively. Overall average particulate deposition velocity was 5.5+/-3.5 cm s(-1). The spatial distribution of Sigma(41)-PCB soil concentrations (n=48) showed that the iron-steel plants, ship dismantling facilities, refinery and petrochemicals complex are the major sources in the area. Calculated air-soil exchange fluxes indicated that the contaminated soil is a secondary source to the atmosphere for lighter PCBs and as a sink for heavier ones. Comparable magnitude of gas exchange and dry particle deposition fluxes indicated that both mechanisms are equally important for PCB movement between air and soil in Aliaga.

  2. Biomassa microbiana em amostras de solos secadas ao ar e reumedecidas Microbial biomass in air dried and rewetted soil samples

    Directory of Open Access Journals (Sweden)

    Antônio Samarão Gonçalves

    2002-05-01

    Full Text Available O objetivo do trabalho foi avaliar a viabilidade do condicionamento de amostras como terra fina secada ao ar (TFSA por curto período, para a determinação do carbono da biomassa microbiana (BMS-C, pelo método da fumigaçãoextração, e verificar a respiração microbiana basal (RB do solo. O condicionamento como TFSA, procedendo-se à fumigação para a análise da BMS-C imediatamente ou 24 horas após o reumedecimento, proporcionou valores de BMS-C para os solos Podzólicos, Latossolo Vermelho-Amarelo álico e Orgânico, semelhantes aos valores dos seus controles. Os solos Glei Pouco Húmico e Vertissolo apresentaram valores de BMS-C similares aos do controle a partir de 24 horas de incubação; o solo Planossolo arenoso apresentou valores similares aos do controle com 72 horas, e a Rendizina, com 168 horas de incubação. Na maioria dos solos, a RB determinada na TFSA apresentou valores maiores do que os do tratamento-controle, quando avaliada imediatamente ou 24 horas após o reumedecimento a 60% da capacidade máxima de retenção de água, seguida de queda e manutenção em níveis semelhantes ao do controle nos períodos subseqüentes. O précondicionamento, de curta duração, como TFSA, é promissor para a determinação da BMS-C, quando níveis e períodos adequados de reumedecimento são adotados.The objective of this work was to evaluate the utilization of short term air dried soil samples in a determination of soil microbial biomass (SMB-C, by a fumigationextraction method, and soil microbial basal respiration (BR. Zero time or 24 hours rewetting incubation period before fumigation procedure gave values of SMB-C similar to those of the control for the Podzolic soils, Allic RedYellow Latosol and Organic soil. Low Humic Gley and Vertisol soils gave values of SMB-C similar to those of the control for periods of incubation equal or higher than 24 hours. Planosol (sandy soil and Rendzina soils gave values of SMB-C similar to the

  3. Rate of Decomposition of Organic Matter in Soil as Influenced by Repeated Air Drying-Rewetting and Repeated Additions of Organic Material

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst

    1974-01-01

    Repeated air drying and rewetting of three soils followed by incubation at 20°C resulted in an increase in the rate of decomposition of a fraction of 14C labeled organic matter in the soils. The labeled organic matter originated from labeled glucose, cellulose and straw, respectively, metabolized...... of the treatment was least in the soil which had been incubated with the labeled material for the longest time. Additions of unlabeled, decomposable organic material also increased the rate of decomposition of the labeled organic matter. The evolution of labeled CO2 during the 1st month of incubation after...... addition was in some cases 4–10 times larger than the evolution from the controls. During the continued incubation the evolution decreased almost to the level of the controls, indicating that the effect was related to the increased biological activity in the soils during decomposition of the added material...

  4. Air dehumidification and drying processes

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, R.

    1988-07-01

    Details are given on the physical principles of air dehumidification and drying as well as on appropriate systems available on the market. Reference is made to dehumidification through condensation (intermittent compressor or electric auxiliary heater defrosting, reversible-circuit hot gas bypass defrosting), air drying through sorption (sorbents, regeneration through heat inputs), the operation of absorptive dryers (schematic sketches), and the change of state of air (Mollier h,x-diagramm). Practical examples refer to the dehumidification of storage rooms, archives, and waterworks as well as to air drying in the pharmaceutical industry, the pastry and candy industry, the food industry, and the drying (preservation) of turbines and generators during long standstill periods. A diagramm shows that while adsorption processes are efficient at temperatures below 80/sup 0/C, low-temperature dehumidification is efficient at temperatures above. (HWJ).

  5. Carrageenan drying with dehumidified air: drying characteristics and product quality

    NARCIS (Netherlands)

    Djaeni, M.; Sasongko, S.B.; Prasetyaningrum, Aji A A.A.; Jin, X.; Boxtel, van A.J.B.

    2012-01-01

    Applying dehumidified air is considered as an option to retain quality in carrageenan drying. This work concerns the effects of operational temperature, air velocity, and carrageenan thickness on the progress of drying and product quality when using dehumidified air. Final product quality and

  6. Design of dry sand soil stratified sampler

    Science.gov (United States)

    Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

    2018-04-01

    This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

  7. Accelerating oak air drying by presurfacing

    Science.gov (United States)

    W. T. Simpson; R. C. Baltes

    1972-01-01

    A comparison was made between the air-drying rates of rough and presurfaced northern red oak and white oak. In both species, the presurfaced material was about 1/8 inch thinner than the rough material and dried faster than the rough material. The reduction in drying time depends on the method of analyzing the drying curves, but is slightly less than 10 percent.

  8. High strength air-dried aerogels

    Science.gov (United States)

    Coronado, Paul R.; Satcher, Jr., Joe H.

    2012-11-06

    A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

  9. Drying and decontamination of pistachios with sequential infrared drying, tempering and hot air drying

    Science.gov (United States)

    The pistachio industry is in need of improved drying technology as the current hot air drying has low energy efficiency and drying rate and high labor cost and also does not produce safe products against microbial contamination. In the current study, dehulled and water- sorted pistachios with a mois...

  10. Wet–dry cycles impact DOM retention in subsurface soils

    Directory of Open Access Journals (Sweden)

    Y. Olshansky

    2018-02-01

    Full Text Available Transport and reactivity of carbon in the critical zone are highly controlled by reactions of dissolved organic matter (DOM with subsurface soils, including adsorption, transformation and exchange. These reactions are dependent on frequent wet–dry cycles common to the unsaturated zone, particularly in semi-arid regions. To test for an effect of wet–dry cycles on DOM interaction and stabilization in subsoils, samples were collected from subsurface (Bw horizons of an Entisol and an Alfisol from the Catalina-Jemez Critical Zone Observatory and sequentially reacted (four batch steps with DOM extracted from the corresponding soil litter layers. Between each reaction step, soils either were allowed to air dry (wet–dry treatment before introduction of the following DOM solution or were maintained under constant wetness (continually wet treatment. Microbial degradation was the dominant mechanism of DOM loss from solution for the Entisol subsoil, which had higher initial organic C content, whereas sorptive retention predominated in the lower C Alfisol subsoil. For a given soil, bulk dissolved organic C losses from solution were similar across treatments. However, a combination of Fourier transform infrared (FTIR and near-edge X-ray absorption fine structure (NEXAFS spectroscopic analyses revealed that wet–dry treatments enhanced the interactions between carboxyl functional groups and soil particle surfaces. Scanning transmission X-ray microscopy (STXM data suggested that cation bridging by Ca2+ was the primary mechanism for carboxyl association with soil surfaces. STXM data also showed that spatial fractionation of adsorbed OM on soil organo-mineral surfaces was diminished relative to what might be inferred from previously published observations pertaining to DOM fractionation on reaction with specimen mineral phases. This study provides direct evidence of the role of wet–dry cycles in affecting sorption reactions of DOM to a complex soil

  11. Wet-dry cycles impact DOM retention in subsurface soils

    Science.gov (United States)

    Olshansky, Yaniv; Root, Robert A.; Chorover, Jon

    2018-02-01

    Transport and reactivity of carbon in the critical zone are highly controlled by reactions of dissolved organic matter (DOM) with subsurface soils, including adsorption, transformation and exchange. These reactions are dependent on frequent wet-dry cycles common to the unsaturated zone, particularly in semi-arid regions. To test for an effect of wet-dry cycles on DOM interaction and stabilization in subsoils, samples were collected from subsurface (Bw) horizons of an Entisol and an Alfisol from the Catalina-Jemez Critical Zone Observatory and sequentially reacted (four batch steps) with DOM extracted from the corresponding soil litter layers. Between each reaction step, soils either were allowed to air dry (wet-dry treatment) before introduction of the following DOM solution or were maintained under constant wetness (continually wet treatment). Microbial degradation was the dominant mechanism of DOM loss from solution for the Entisol subsoil, which had higher initial organic C content, whereas sorptive retention predominated in the lower C Alfisol subsoil. For a given soil, bulk dissolved organic C losses from solution were similar across treatments. However, a combination of Fourier transform infrared (FTIR) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopic analyses revealed that wet-dry treatments enhanced the interactions between carboxyl functional groups and soil particle surfaces. Scanning transmission X-ray microscopy (STXM) data suggested that cation bridging by Ca2+ was the primary mechanism for carboxyl association with soil surfaces. STXM data also showed that spatial fractionation of adsorbed OM on soil organo-mineral surfaces was diminished relative to what might be inferred from previously published observations pertaining to DOM fractionation on reaction with specimen mineral phases. This study provides direct evidence of the role of wet-dry cycles in affecting sorption reactions of DOM to a complex soil matrix. In the soil

  12. Design of dry barriers for containment of contaminants in unsaturated soils

    International Nuclear Information System (INIS)

    Morris, C.E.; Thomson, B.M.; Stormont, J.C.

    1997-01-01

    A dry barrier is a region of very dry conditions in unsaturated soil that prevents vertical migration of water created by circulating dry air through the formation. Dry soil creates a barrier to vertical water movement by decreasing the soil's hydraulic conductivity, a concept also used in capillary barriers. A dry barrier may be a viable method for providing containment of a contaminant plume in a setting with a thick unsaturated zone and dry climate. The principal factors which determine the feasibility of a dry barrier include: (1) an and environment, (2) thick vadose zone, and (3) the ability to circulate air through the vadose zone. This study investigated the technical and economic considerations associated with creating a dry barrier to provide containment of a hypothetical 1 ha aqueous contaminant plume. The concept appears to be competitive with other interim containment methods such as ground freezing

  13. Dry and mixed air cooling systems

    International Nuclear Information System (INIS)

    Gutner, Gidali.

    1975-01-01

    The various dry air cooling systems now in use or being developed are classified. The main dimensioning parameters are specified and the main systems already built are given with their characteristics. The available data allow dry air cooling to be situated against the other cooling modes and so specify the aim of the research or currently developed works. Some systems at development stages are briefly described. The interest in mixed cooling (assisted draft) and the principal available systems is analyzed. A program of research is outlined [fr

  14. Drier for air-drying coatings

    NARCIS (Netherlands)

    Micciche, F.; Oostveen, E.A.; Linde, van der R.; Haveren, van J.

    2003-01-01

    The invention pertains to a drier composition for air-drying alkyd-based coatings, inks, or floor coverings, comprising a combination of the following components: a) a transition metal salt with the formula: (Me )( X )m in which Me is the transition metal; X represents a coordinating ligand; and k-

  15. Drying shrinkage problems in high PI subgrade soils.

    Science.gov (United States)

    2014-01-01

    The main objective of this study was to investigate the longitudinal cracking in pavements due to drying : shrinkage of high PI subgrade soils. The study involved laboartory soil testing and modeling. The : shrinkage cracks usually occur within the v...

  16. Infiltration Variability in Agricultural Soil Aggregates Caused by Air Slaking

    Science.gov (United States)

    Korenkova, L.; Urik, M.

    2018-04-01

    This article reports on variation in infiltration rates of soil aggregates as a result of phenomenon known as air slaking. Air slaking is caused by the compression and subsequent escape of air captured inside soil aggregates during water saturation. Although it has been generally assumed that it occurs mostly when dry aggregates are rapidly wetted, the measurements used for this paper have proved that it takes place even if the wetting is gradual, not just immediate. It is a phenomenon that contributes to an infiltration variability of soils. In measuring the course of water flow through the soil, several small aggregates of five agricultural soils were exposed to distilled water at zero tension in order to characterize their hydraulic properties. Infiltration curves obtained for these aggregates demonstrate the effect of entrapped air on the increase and decrease of infiltration rates. The measurements were performed under various moisture conditions of the A-horizon aggregates using a simple device.

  17. Ultrasound-Assisted Hot Air Drying of Foods

    Science.gov (United States)

    Mulet, Antonio; Cárcel, Juan Andrés; García-Pérez, José Vicente; Riera, Enrique

    This chapter deals with the application of power ultrasound, also named high-intensity ultrasound, in the hot air drying of foods. The aim of ultrasound-assisted drying is to overcome some of the limitations of traditional convective drying systems, especially by increasing drying rate without reducing quality attributes. The effects of ultrasound on drying rate are responsible for some of the phenomena produced in the internal and/or external resistance to mass transfer.

  18. Microwave and hot air drying of garlic puree: drying kinetics and quality characteristics

    Science.gov (United States)

    İlter, Işıl; Akyıl, Saniye; Devseren, Esra; Okut, Dilara; Koç, Mehmet; Kaymak Ertekin, Figen

    2018-02-01

    In this study, the effect of hot air and microwave drying on drying kinetics and some quality characteristics such as water activity, color, optic index and volatile oil of garlic puree was investigated. Optic index representing browning of the garlic puree increased excessively with an increase in microwave power and hot air drying temperature. However, volatile oil content of the dried samples was decreased by increasing of temperature and microwave power. By increasing drying temperature (50, 60 and 70 °C) and microwave power (180, 360 and 540 W), the drying time decreased from 8.5 h to 4 min. In order to determine the kinetic parameters, the experimental drying data were fitted to various semi-empirical models beside 2nd Fick's diffusion equation. Among them, the Page model gave a better fit for microwave-drying, while Logarithmic model gave a better fit for hot air drying. By increasing the microwave power and hot air drying temperature, the effective moisture diffusivity, De values ranged from 0.76×10-8 to 2.85×10-8 m2/s and from 2.21×10-10 to 3.07×10-10 m2/s, respectively. The activation energy was calculated as 20.90 kJ/mol for hot air drying and 21.96 W/g for microwave drying using an Arrhenius type equation.

  19. Do we know how plants sense a drying soil?

    Directory of Open Access Journals (Sweden)

    Streck Nereu Augusto

    2004-01-01

    Full Text Available The reduction of crop growth and yield in dry areas is largely due to stomatal closure in response to dry soil, which decreases photosynthesis. However, the mechanism that causes stomatal closure in a drying soil is a controversial issue. Experienced and respected plant physiologists around the world have different views about the primary sensor of soil water shortage in plants. The goal of this review is to present a chronological synthesis about the evidence of the possible candidates for the mechanism by which plants sense a drying soil. Hydraulic signals in the leaves as the mechanism that causes stomatal closure dominated the view on how plants sense a drying soil during the 70?s and the early 80?s. In the middle 80?s, studies suggested that stomatal conductance is better correlated with soil and root water status than with leaf water status. Thus, chemical signals produced in the roots dominated the view on how plants sense a drying soil during the late 80?s and early 90?s. During the second half of the 90?s, however, studies provided evidence that hydraulic signals in the leaves are still better candidates for the mechanism by which plants sense a drying soil. After more than 60 years of studies in plant-water relations, the question raised in the title still has no unanimous answer. This controversial issue is a good research rationale for the current generation of plant physiologists.

  20. Description of saturation curves and boiling process of dry air

    Directory of Open Access Journals (Sweden)

    Vestfálová Magda

    2018-01-01

    Full Text Available Air is a mixture of gases forming the gas wrap of Earth. It is formed by dry air, moisture and other pollutants. Dry air is a substance whose thermodynamic properties in gaseous state, as well as the thermodynamic properties of its main constituents in gaseous state, are generally known and described in detail in the literature. The liquid air is a bluish liquid and is industrially used to produce oxygen, nitrogen, argon and helium by distillation. The transition between the gaseous and liquid state (the condensation process, resp. boiling process, is usually displayed in the basic thermodynamic diagrams using the saturation curves. The saturation curves of all pure substances are of a similar shape. However, since the dry air is a mixture, the shapes of its saturation curves are modified relative to the shapes corresponding to the pure substances. This paper deals with the description of the dry air saturation curves as a mixture, i.e. with a description of the process of phase change of dry air (boiling process. The dry air saturation curves are constructed in the basic thermodynamic charts based on the values obtained from the literature. On the basis of diagrams, data appearing in various publications are interpreted and put into context with boiling process of dry air.

  1. Nutritional responses to soil drying and rewetting cycles under partial root-zone drying irrigation

    DEFF Research Database (Denmark)

    Wang, Yaosheng; Jensen, Christian Richardt; Liu, Fulai

    2017-01-01

    signaling that regulates stomatal aperture. PRI induced soil DRW cycles and more soil water dynamics in the root zone enhance soil nutrient mineralization process and thus increase the bioavailability of soil nutrients, resulting in improved nitrogen (N) and phosphorus (P) uptake, in which soil microbial...... processes play a key role. Studies investigating how soil DRW cycles and water dynamics under PRI on nutrient transport in soil solution, soil microbe mediated P transformation, interactions between phytohormones and nutrient uptake, root morphological and architectural traits for nutrient acquisition......Abstract Repeated soil drying and rewetting (DRW) cycles occur in rainfed and irrigated agriculture. The intensity and frequency of DRW cycles regulate both microbial physiology and soil physical processes, hereby affecting the mineralization and immobilization of soil nutrients...

  2. Mineralogy of Antarctica Dry Valley Soils: Implications for Pedogenic Processes on Mars

    Science.gov (United States)

    Quinn, J. E.; Ming, D. W.; Morris, R. V.; Douglas, S.; Kounaves, S. P.; McKay, C. P.; Tamppari, L, K.; Smith, P. H.; Zent, A. P.; Archer, P. D., Jr.

    2010-01-01

    The Antarctic Dry Valleys (ADVs) located in the Transantarctic Mountains are the coldest and driest locations on Earth. The mean annual air temperature is -20 C or less and the ADVs receive 100mm or less of precipitation annually in the form of snow. The cold and dry climate in the ADVs is one of the best terrestrial analogs for the climatic conditions on Mars [2]. The soils in the ADVs have been categorized into three soil moisture zones: subxerous, xerous and ultraxerous. The subxerous zone is a coastal region in which soils have ice-cemented permafrost relatively close to the surface. Moisture is available in relatively large amounts and soil temperatures are above freezing throughout the soil profile (above ice permafrost) in summer months. The xerous zone, the most widespread of the three zones, is an inland region with a climate midway between the subxerous and ultraxerous. The soils from this zone have dry permafrost at moderate depths (30-75cm) but have sufficient water in the upper soil horizons to allow leaching of soluble materials. The ultraxerous zone is a high elevation zone, where both temperature and precipitation amounts are very low resulting in dry permafrost throughout the soil profile. The three moisture regime regions are similar to the three microclimatic zones (coastal thaw, inland mixed, stable upland) defined by Marchant and Head.

  3. Cold Vacuum Drying Instrument Air System Design Description (SYS 12)

    Energy Technology Data Exchange (ETDEWEB)

    SHAPLEY, B.J.; TRAN, Y.S.

    2000-06-05

    This system design description (SDD) addresses the instrument air (IA) system of the spent nuclear fuel (SNF). This IA system provides instrument quality air to the Cold Vacuum Drying (CVD) Facility. The IA system is a general service system that supports the operation of the heating, ventilation, and air conditioning (HVAC) system, the process equipment skids, and process instruments in the CVD Facility. The following discussion is limited to the compressor, dryer, piping, and valving that provide the IA as shown in Drawings H-1-82222, Cold Vacuum Drying Facility Mechanical Utilities Compressed & Instrument Air P&ID, and H-1.82161, Cold Vacuum Drying Facility Process Equipment Skid P&ID MCO/Cusk Interface. Figure 1-1 shows the physical location of the 1A system in the CVD Facility.

  4. Cold Vacuum Drying Instrument Air System Design Description. System 12

    International Nuclear Information System (INIS)

    SHAPLEY, B.J.; TRAN, Y.S.

    2000-01-01

    This system design description (SDD) addresses the instrument air (IA) system of the spent nuclear fuel (SNF). This IA system provides instrument quality air to the Cold Vacuum Drying (CVD) Facility. The IA system is a general service system that supports the operation of the heating, ventilation, and air conditioning (HVAC) system, the process equipment skids, and process instruments in the CVD Facility. The following discussion is limited to the compressor, dryer, piping, and valving that provide the IA as shown in Drawings H-1-82222, Cold Vacuum Drying Facility Mechanical Utilities Compressed and Instrument Air PandID, and H-1.82161, Cold Vacuum Drying Facility Process Equipment Skid PandID MCO/Cusk Interface. Figure 1-1 shows the physical location of the 1A system in the CVD Facility

  5. Predicting the water-drop energy required to breakdown dry soil aggregates

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.; Bazzoffi, P.

    1995-04-01

    The raindrop energy required to breakdown dry soil aggregates is an index of structural stability which has been found very useful in modelling soil erosion process and in evaluating the suitability of tillage implements for different soils. The aim of this research was to develop and validate a model for predicting the specific water-drop energy required to breakdown aggregates (D) as influenced by soil properties. Air-dry aggregates (2-4 mm in diameter), collected from 15 surface (0-20 cm) soils in north central Italy were used for this study. The actual and natural log-transformed D values were regressed on the soil properties. Clay content, wilting point moisture content (WP) and percent water-stable aggregates (WSA) > 2.0 mm were good predictors of D. Empirical models developed from either clay content or WP predicted D in 70% of the test soils whereas the model developed from WSA > 2.0 mm predicted D in 90% of the test soils. The correlation coefficients (r) between measured and predicted D were 0.961, 0.963 and 0.997 respectively, for models developed from clay, WP and WSA > 2.0 mm. The validity of these models need to be tested on other soils with a wider variation in properties than those used to developed the models. (author). 42 refs, 5 tabs

  6. Microbial community composition of transiently wetted Antarctic Dry Valley soils.

    Science.gov (United States)

    Niederberger, Thomas D; Sohm, Jill A; Gunderson, Troy E; Parker, Alexander E; Tirindelli, Joëlle; Capone, Douglas G; Carpenter, Edward J; Cary, Stephen C

    2015-01-01

    During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm(3) for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

  7. LIMITATION OF SOIL RESPIRATION DURING DRY PERIOD

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Marian; Janouš, Dalibor; Acosta, Manuel

    2003-01-01

    Roč. 16, - (2003), s. 47-52. ISBN 80-7157-297-7 R&D Projects: GA MŠk LN00A141; GA AV ČR IBS6087005 Institutional research plan: CEZ:AV0Z6087904 Keywords : moisture * Norway spruce * precipitation * respiration * soil CO2 efflux Subject RIV: EH - Ecology, Behaviour

  8. Determination of the most economical drying schedule and air velocity in softwood drying

    Energy Technology Data Exchange (ETDEWEB)

    Salin, J.G.

    2001-12-01

    Simulation models for conventional softwood drying have been available and have also been used by kiln operators for many years. For instance models for Scots pine and Norway spruce, dried at temperatures below about 80 deg C, are in use in Sweden, Finland and Norway. These models predict drying rates as a function of climate (schedule) and air velocity. The models thus give a direct basis for calculation of instantaneous energy demand for moisture evaporation and ventilation. There is further a direct relationship between the air velocity in the space between the board layers in the kiln stack and the electrical power demand by the circulation fans. Finally, the smaller energy consumption associated with heat losses through kiln walls and the accumulated heat in timber etc. can be estimated with sufficient accuracy. Instantaneous energy costs can thus be calculated for each part of a drying schedule. Capital costs associated with kiln investment and maintenance, personnel, insurance etc can be accounted for as an hourly cost, which is basically independent of whether timber is dried fast or slowly. A slow drying process thus accumulates more capital costs per m 3 timber. In this way it is possible to calculate the total instantaneous drying cost (Euro/m{sup 3}/h or Euro/m3/MC%) and the overall total cost (Euro or Euro/m{sup 3}). Some results obtained with a simulation model equipped with such a cost calculation are presented in the paper. A rapidly increasing drying cost is seen when the final MC is lowered. By minimising the instantaneous cost, an optimal drying schedule can be determined for a given fixed air velocity. Finally an optimal air velocity - constant or varying - can be found in the same way.

  9. Bioindicator demonstrates high persistence of sulfentrazone in dry soil

    Directory of Open Access Journals (Sweden)

    Renato Coradello Lourenço

    2015-09-01

    Full Text Available In sugarcane crop areas, the application of preemergence herbicides with long residual effect in the soil has been frequently necessary. The herbicide persistence in the soil must be high especially because of applications during the dry season of the year, after sugarcane harvest. This study aimed at estimating the sulfentrazone persistence and dissipation in dry soil using bioindicator. Five experiments were carried out, divided into two phases. In the first phase, three dose-response curves were adjusted to select the best bioindicator to be adopted in the second phase. Niger was adopted due to its lower sensibility to sulfentrazone. In the second phase, a new dose-response curve was carried out, with six doses of sulfentrazone, in order to standardize the bioindicator sensibility to sulfentrazone. At the end, another experiment with six periods of sulfentrazone persistence in dry clay soil was developed. Persistence periods were: 182, 154, 125, 98 and 30 days. The bioindicator was seeded at the application day in treated plots and control. In this experiment, the sulfentrazone dose applied was 800 g ha-1. Niger was considered a good species to estimate the sulfentrazone persistence in dry soil. The sulfentrazone phytotoxic activity was identified up to 182 days after application, and its average dissipation rate was 2.15 g ha-1 day-1, with half-life higher than 182 days.

  10. Experimental and theoretical analysis of cracking in drying soils

    OpenAIRE

    Lakshmikantha, M.R.

    2009-01-01

    The thesis focuses on the experimental and theoretical aspects of the process of cracking in drying soils. The results and conclusions were drawn from an exhaustive experimental campaign characterised by innovative multidisciplinary aspects incorporating Fracture Mechanics and classical Soil mechanics, aided with image analysis techniques. A detailed study of the previous works on the topic showed the absence of large scale fully monitored laboratory tests, while the existing studies were per...

  11. Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Hamamoto, S; Kawamoto, K

    2012-01-01

    Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas...... dispersion and soil physical characteristics. In this study, a series of advection–dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas...... dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (a = DH/v, where v...

  12. Application of Natural Air Drying on Shelled Corn in Timor

    Science.gov (United States)

    Nino, J.; Nelwan, L. O.; Purwanto, Y. A.

    2018-05-01

    A study of the application of natural air drying on shelled corn in Timor using a bed- type dryer has been performed. The study aspects were limited to obtain the suitable air flow rate requirement and duration of the drying operation per day. For each aspect, the treatments were carried out simultaneously. The results showed that at the average ambient air temperature of 30.6°C and relative humidity (RH) of 73.0% the air flow rate of 0.83 L/s-kg provided the highest drying rate. Subsequently, by using the same air flow rate, three scheme of drying operations duration were used, i.e., 8 hours per day (08.00-16.00), 6 hours per day (09.00-15.00) and 4 hours per day (10.00-14.00). The average temperature and RH of ambient air condition at the second experiment were 30.3°C and 73.3% respectively. After 4 days of drying, the 8 hours per day (first scheme) treatment was able to dry the shelled corn from the initial moisture content of 27.24% w.b. to the final moisture content of 14.05% w.b. The specific energy consumption (SEC) of the first scheme was 1.75 MJ/kg. The final moisture content of the second and third schemes were 15.08 % w.b. and 18.45 % w.b. respectively with SEC of 1.41 MJ/kg and 1.21 MJ/kg respectively.

  13. Soil aggregate and organic carbon distribution at dry land soil and paddy soil: the role of different straws returning.

    Science.gov (United States)

    Huang, Rong; Lan, Muling; Liu, Jiang; Gao, Ming

    2017-12-01

    Agriculture wastes returning to soil is one of common ways to reuse crop straws in China. The returned straws are expected to improve the fertility and structural stability of soil during the degradation of straw it selves. The in situ effect of different straw (wheat, rice, maize, rape, and broad bean) applications for soil aggregate stability and soil organic carbon (SOC) distribution were studied at both dry land soil and paddy soil in this study. Wet sieving procedures were used to separate soil aggregate sizes. Aggregate stability indicators including mean weight diameter, geometric mean diameter, mean weight of specific surface area, and the fractal dimension were used to evaluate soil aggregate stability after the incubation of straws returning. Meanwhile, the variation and distribution of SOC in different-sized aggregates were further studied. Results showed that the application of straws, especially rape straw at dry land soil and rice straw at paddy soil, increased the fractions of macro-aggregate (> 0.25 mm) and micro-aggregate (0.25-0.053 mm). Suggesting the nutrients released from straw degradation promotes the growing of soil aggregates directly and indirectly. The application of different straws increased the SOC content at both soils and the SOC mainly distributed at  0.25 and 0.25-0.053 mm aggregates with dry land soil. Rape straw in dry land and rice straw in paddy field could stabilize soil aggregates and increasing SOC contents best.

  14. Pulsed Streamer Discharge Characteristics of Ozone Production in Dry Air

    OpenAIRE

    Samaranayake, W.J.M.; Miyahara, Y.; Namihira, T.; Katsuki, S.; Sakugawa, T.; Hackam, R.; Akiyama, H.; ナミヒラ, タカオ; カツキ, スナオ; アキヤマ, ヒデノリ; 波平, 隆男; 勝木, 淳; 秋山, 秀典

    2000-01-01

    Experimental investigation of HV short pulsed streamer discharges in dry air-fed ozonizers under various operating conditions are reported. Ozone concentration, energy input and ozone production yield (efficiency) were measured at various voltages (14 to 37 kV), pulse repetition rates (25 to 400 pulses per second, pps), flow rates (1.5 to 3.0 1/min) and different gap spacings (10 to 20 mm) at a pressure of 1.01×105 Pa in dry air. A spiral copper wire (1 mm in diameter) made to a cylindrical c...

  15. Drying kinetics and mathematical modeling of hot air drying of coconut coir pith.

    Science.gov (United States)

    Fernando, J A K M; Amarasinghe, A D U S

    2016-01-01

    Drying kinetics of coir pith was studied and the properties of compressed coir pith discs were analyzed. Coir pith particles were oven dried in the range of temperatures from 100 to 240 °C and the rehydration ability of compressed coir pith was evaluated by finding the volume expansion. The optimum drying temperature was found to be 140 °C. Hot air drying was carried out to examine the drying kinetics by allowing the coir pith particles to fluidize and circulate inside the drying chamber. Particle motion within the drying chamber closely resembled the particle motion in a flash dryer. The effective moisture diffusivity was found to increase from 1.18 × 10(-8) to 1.37 × 10(-8) m(2)/s with the increase of air velocity from 1.4 to 2.5 m/s respectively. Correlation analysis and residual plots were used to determine the adequacy of existing mathematical models for describing the drying behavior of coir pith. The empirical models, Wang and Singh model and Linear model, were found to be adequate for accurate prediction of drying behavior of coir pith. A new model was proposed by modifying the Wang and Singh model and considering the effect of air velocity. It gave the best correlation between observed and predicted moisture ratio with high value of coefficient of determination (R(2)) and lower values of root mean square error, reduced Chi square (χ(2)) and mean relative deviation (E%).

  16. Air separation of heavy metal contaminants from soil

    International Nuclear Information System (INIS)

    Nelson, M.E.; Harper, M.J.; Buckon, A.D.

    1995-01-01

    Several heavy metal separation techniques are currently being developed for soil remediation at various Department of Defense and Department of Energy (DOE) Facilities. The majority of these techniques involve a wet process using water, pH modifiers or other compounds. The US Naval Academy (USNA) has developed a dry process for heavy metal separation. The process uses air classification technology to concentrate the metal contaminant into a fraction of the soil. The advantages of this dry process are that it creates no contaminated byproduct and uses commercially available technology. The USNA process is based on using a Gayco-Reliance air classifier. Tests have been conducted with the system at the Naval Academy and the University of Nevada-Reno (UNR). The USNA tests used soil from the Nevada Test Site mixed with bismuth at a concentration of 500--1,000 ppm. The UNR tests used soil from four DOE sites mixed with uranium oxides and plutonium at an activity level of 100--700 pCi per gram. Concentration of activities and volume reduction percentages are presented for the various soils and contaminants tested

  17. Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

    Science.gov (United States)

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-05

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  18. Physical Properties of Sandy Soil Affected by Soil Conditioner Under Wetting and Drying cycles

    Directory of Open Access Journals (Sweden)

    M.I. Choudhary

    1998-06-01

    Full Text Available Information on the effectiveness of soil conditioners over a prolonged period is scarce. A laboratory experiment was undertaken to evaluate the effectiveness of a polyacrylamide (Broadleaf P4 soil conditioner on the physical properties of sandy soil subjected to wetting and drying cycles. Four concentrations of Broadleaf P4 0, 0.2, 0.4, and 0.6% on dry weight basis were uniformly mixed with a calcareous sandy soil. Addition of Broadleaf P4 to sandy soil increased the water holding capacity, decreased the bulk density, and increased the porosity and void ratio at 0 and 16 wetting and drying cycles. The coefficient of linear extensibility increased considerably with increasing concentrations of the polymer. The addition of polymer at 0 and 16 cycles increased considerably the retention and availability of water in sandy soil. Saturated hydraulic conductivity decreased with increasing concentrations of Broadleaf P4 whereas unsaturated hydraulic conductivity at 0 and 16 cycles showed an increase with increasing soil moisture contents. After I6 wetting and drying cycles, the capacity of the soil to hold water was lost on average by 15.8% when compared to the 0 wetting and drying cycle. The effectiveness of the soil conditioner on bulk density, coefficient of linear extensibility, available water and saturated hydraulic conductivity was reduced on average by 14.1, 24.5, 21.l and 53.7% respectively. The significant changes in soil properties between 0 and 16 cycles suggested that the effectiveness of the conditioner decreased with the application of wetting and drying cycles. However, its effect was still considerable when compared to untreated soil under laboratory conditions.

  19. The effect of air dried conditions on mechanical and physical ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-20

    Apr 20, 2009 ... small dimension wooden material is used and this affects the cost of ... The first serious application of laminating technique ... buildings, stock hangar, farms and stables constructions ... resistant lamine elements to air dried condition were easy .... the other was organic solvent water repellent protim WR230.

  20. Preparation of Natural Zeolite for Air Dehumidification in Food Drying

    Directory of Open Access Journals (Sweden)

    Mohamad Djaeni

    2015-03-01

    Full Text Available Drying with air dehumidification with solid adsorbent improves the quality of food product as well as energy efficiency. The natural zeolite is one of adsorbent having potential to adsorb the water.  Normally, the material was activated to open the pore, remove the organic impurities, and increase Si/Al rate. Hence, it can enhance the adsorbing capacity. This research studied the activation of natural zeolite mined from Klaten, Indonesia as air dehumidification for food drying. Two different methods were used involving activation by heat and NaOH introduction.  As indicators, the porosity and water loaded were evaluated. Results showed both methods improved the adsorbing capacity significantly. With NaOH, the adsorbing capacity was higher. The simple test in onion and corn drying showed the presence of activated natural zeolite can speed up water evaporation positively. This performance was also comparable with Zeolite 3A

  1. Dry coolers and air-condensing units (Review)

    Science.gov (United States)

    Milman, O. O.; Anan'ev, P. A.

    2016-03-01

    The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that

  2. Criticality Analysis of SFP Region I under Dry Air Condition

    International Nuclear Information System (INIS)

    Kim, Ki Yong; Kim, Min Chul

    2016-01-01

    This paper is to provide a result of the criticality evaluation under the condition that new fuel assemblies for initial fuel loading are storing in Region 1 of SFP in the dry air. The objective of this analysis is to ensure the effective neutron multiplication factor(k_e_f_f) of SFP is less than 0.95 under that condition. This analysis ensured the effective neutron multiplication factor(k_e_f_f) of Region 1 of SFP is less than 0.95 under the condition in the air. The keff in Region I of SFP under the condition of the dry air is 0.5865. The increased k_c_a_l_c of the Region 1 after the mislocated fuel assembly accident is 0.0444 at the pool flooded with un-borated water

  3. The use of 36Cl diffusion to asses changes in pore geometry of allophane soils resulting from drying

    International Nuclear Information System (INIS)

    Holder, G.D.

    1984-01-01

    The apparent diffusion coefficient of 36 Cl is used to assess pore geometric changes in allophane soil resulting from drying. The diffusion method is based on the boundary condition of a planar source diffusing into an infinite medium. The extent of structural changes accompanying drying was indicated by changes in slope of a plot between geometric and interaction factors versus volumetric moisture content. Structural change was least for freeze drying to be followed by a larger but equal change for air and oven drying. (M.A.C.) [pt

  4. Pysical Properties of Soil with Addition of Sewage Dried with Heated Edible Oil

    OpenAIRE

    大坪, 政美; 中司, 敬; 中園, 修三; 中園, 英司; 徳留, 斉将

    2000-01-01

    The present study investigates the water holding capacity, density, permeability, and swelling properties of the soil samples mixed with the sewage that was dried with heated edible oil. For comparison similar experiments were conducted for the soil samples mixed with sun-dried sewage and sewage compost. The water holding capacity was higher for the soil samples with oil-dried and sun-dried sewage addition than for those with sewage-compost addition. For statically compacted soil samples, wit...

  5. Effects of open-air sun drying and pre-treatment on drying characteristics of purslane ( Portulaca oleracea L.)

    Science.gov (United States)

    İsmail, Osman; Kantürk Figen, Aysel; Pişkin, Sabriye

    2015-06-01

    Effects of open-air sun drying and pre-treatment on drying characteristic of purslanes ( Portulaca oleracea L.) were investigated. Drying times were determined as 31, 24 and 9 h for natural, salted and blanched, respectively. The higher "L" value and lower "-a/b" ratio values were obtained in natural dried purslane. The Aghbashlo et al. model gave a better fit to drying data.

  6. Soil macrofauna (invertebrates of Kazakhstanian Stipa lessingiana dry steppe

    Directory of Open Access Journals (Sweden)

    Bragina Tatyana М.

    2016-12-01

    Full Text Available Stipa lessingiana steppes used to be prevalent on the dry Trans-Ural denudation plains, particularly, on the Sub-Ural and the Turgay Plateau. But, most of them have been lost because they were plowed up during the Virgin Land campaign in the second part of 20th century. This paper presents a detailed study of the faunistic composition and the structure of soil-dwelling invertebrate communities (macrofauna of a temperate-dry bunch feather grass steppe in the Turgai Plateau (Northern-Turgai physical-geographical province of steppe Kazakhstan, Kostanay Oblast. The study site is located in the territory of the Naurzum State Nature Reserve, a part of the UNESCO World Heritage site “Saryarka Steppe and Lakes of Northern Kazakhstan”, where remnants of Virgin S. lessingiana steppes have been preserved to the present day. This region is the driest and most continental in climate of all the dry steppes of Kazakhstan. The total abundance and biomass of soil invertebrate communities in the investigated site were lower than in the northern and western steppe areas. Soil invertebrates are among the major components that determine the functioning of terrestrial natural ecosystems.

  7. Development of a distributed air pollutant dry deposition modeling framework

    International Nuclear Information System (INIS)

    Hirabayashi, Satoshi; Kroll, Charles N.; Nowak, David J.

    2012-01-01

    A distributed air pollutant dry deposition modeling system was developed with a geographic information system (GIS) to enhance the functionality of i-Tree Eco (i-Tree, 2011). With the developed system, temperature, leaf area index (LAI) and air pollutant concentration in a spatially distributed form can be estimated, and based on these and other input variables, dry deposition of carbon monoxide (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and particulate matter less than 10 microns (PM10) to trees can be spatially quantified. Employing nationally available road network, traffic volume, air pollutant emission/measurement and meteorological data, the developed system provides a framework for the U.S. city managers to identify spatial patterns of urban forest and locate potential areas for future urban forest planting and protection to improve air quality. To exhibit the usability of the framework, a case study was performed for July and August of 2005 in Baltimore, MD. - Highlights: ► A distributed air pollutant dry deposition modeling system was developed. ► The developed system enhances the functionality of i-Tree Eco. ► The developed system employs nationally available input datasets. ► The developed system is transferable to any U.S. city. ► Future planting and protection spots were visually identified in a case study. - Employing nationally available datasets and a GIS, this study will provide urban forest managers in U.S. cities a framework to quantify and visualize urban forest structure and its air pollution removal effect.

  8. Evaluation of beetroot changes during drying with hot air by digital ...

    African Journals Online (AJOL)

    Foods drying are an important operation in processing and increasing foodstuffs shelf life and many factors effected on products efficiency and quality during drying. Deterioration of texture structure and products color changes depends on drying method and air temperature and air rate. Drying or removing maximum water ...

  9. Phenome data - Air-drying stress - DGBY | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available List Contact us DGBY Phenome data - Air-drying stress Data detail Data name Phenome data - Air-drying stress... DOI 10.18908/lsdba.nbdc00953-007 Description of data contents Yeasts used in bread making are exposed to air-dryin...g stress during dried yeast production processes. To clarify the genes required for air-drying tolera...tion of diploid Saccharomyces cerevisiae . The screening identified 278 gene deletions responsible for air-dryin...heir gene products. The results showed that the genes required for air-drying tol

  10. Excessive Afforestation and Soil Drying on China's Loess Plateau

    Science.gov (United States)

    Zhang, Shuilei; Yang, Dawen; Yang, Yuting; Piao, Shilong; Yang, Hanbo; Lei, Huimin; Fu, Bojie

    2018-03-01

    Afforestation and deforestation as human disturbances to vegetation have profound impacts on ecohydrological processes influencing both water and carbon cycles and ecosystem sustainability. Since 1999, large-scale revegetation activities such as "Grain-to-Green Program" have been implemented across China's Loess Plateau. However, negative ecohydrological consequences, including streamflow decline and soil drying have emerged. Here we estimate the equilibrium vegetation cover over the Loess Plateau based on an ecohydrological model and assess the water balance under the equilibrium and actual vegetation cover over the past decade. Results show that the current vegetation cover (0.48 on average) has already exceeded the climate-defined equilibrium vegetation cover (0.43 on average) in many parts of the Loess Plateau, especially in the middle-to-east regions. This indicates a widespread overplanting, which is found to primarily responsible for soil drying in the area. Additionally, both the equilibrium vegetation cover and soil moisture tend to decrease under future (i.e., 2011-2050) climate scenarios due to declined atmospheric water supply (i.e., precipitation) and increased atmospheric water demand (i.e., potential evapotranspiration). Our findings suggest that further revegetation on the Loess Plateau should be applied with caution. To maintain a sustainable ecohydrological environment in the region, a revegetation threshold is urgently needed to guide future revegetation activities.

  11. Blast load effects research in dry and wet soil

    CSIR Research Space (South Africa)

    Ahmed, R

    2014-09-01

    Full Text Available stream_source_info Ahmed_2014_ABSTRACT.pdf.txt stream_content_type text/plain stream_size 904 Content-Encoding UTF-8 stream_name Ahmed_2014_ABSTRACT.pdf.txt Content-Type text/plain; charset=UTF-8 South African Ballistics... Organisation Conference, Zebra Country Lodge, Gauteng, South Africa, 29 September – 1 October 2014 BLAST LOAD EFFECTS RESEARCH IN DRY AND WET SOIL R Ahmed and ME Miyambo Landward Sciences, Defence Peace Safety and Security, CSIR, PO Box 395, Pretoria...

  12. Mercury fluxes from air/surface interfaces in paddy field and dry land

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Jinshan [Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, No. 216, Tiansheng Street, Beibei, Chongqing 400715 (China); Wang Dingyong, E-mail: dywang@swu.edu.cn [Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, No. 216, Tiansheng Street, Beibei, Chongqing 400715 (China)] [Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716 (China); Liu Xiao; Zhang Yutong [Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, No. 216, Tiansheng Street, Beibei, Chongqing 400715 (China)

    2011-02-15

    Research highlights: {yields} It was found that agricultural fields are important local atmospheric Hg sources in the region. {yields} The Hg emissions from dry cornfield were higher than those from the flooded rice paddy, higher mercury emissions in the warm season than the cold season, and during daytime than at night. {yields} Mercury evasion is strongly related to solar radiation which is important in the emission of Hg at both sites. - Abstract: In order to provide insight into the characteristics of Hg exchange in soil/water-air surface from cropland (including paddy field and dry land), Hg fluxes were measured in Chengjiang. Mercury fluxes were measured using the dynamic flux chamber method, coupled with a Lumex (registered) multifunctional Hg analyzer RA-915{sup +} (Lumex Ltd., Russia). The Hg fluxes from paddy field and dry land were alternatively measured every 30 min. Data were collected for 24-48 h once per month for 5 months. Mercury fluxes in both fields were synchronously measured under the same conditions to compare Hg emissions between paddy field and dry land over diurnal and seasonal periods and find out what factors affect Hg emission on each surface. These results indicated that air Hg concentrations at the monitoring site was double the value observed at the global background sites in Europe and North America. The Hg release fluxes were 46.5 {+-} 22.8 ng m{sup -2} h{sup -1} in the warm season, 15.5 {+-} 18.8 ng m{sup -2} h{sup -1} in the cold season for dry land, and 23.8 {+-} 15.6 ng m{sup -2} h{sup -1} in the warm season, 6.3 {+-} 11.9 ng m{sup -2} h{sup -1} in the cold season for paddy field. Solar radiation is important in the emission of Hg over both sites. Hg exchange at the soil/air and water/air interfaces showed temporal variations. The amount of Hg emission from dry land was higher than that from the paddy field, and the emission in daytime was higher than that at night. Moreover, Hg emissions from land covered by crops, was lower

  13. Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence

    NARCIS (Netherlands)

    Ziogas, A.K.; Dekker, L.W.; Oostindie, K.; Ritsema, C.J.

    2005-01-01

    Many soils may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency often leads to the development of unstable

  14. Drying Characteristics and Water-soluble Polysaccharides Evaluation of Kidney Shape Ganoderma lucidum Drying in Air Circulation System

    Science.gov (United States)

    Prasetyo, D. J.; Jatmiko, T. H.; Poeloengasih, C. D.; Kismurtono, M.

    2017-12-01

    In this project, drying kinetic of kidney shape Ganoderma lucidum fruiting body in air circulation system was studied. The drying experiments were conducted at 40, 50 and 60°C with air flow rate of 1.3 ms-1. Samples were weighted periodically until no change in sample weight was recorded, and then the samples were analyzed for its moisture content. Four different thin-layer mathematical models (Newton, Page, Two-term, Midilli) were used and compare to evaluate the drying curves of kidney shape G. lucidum. The water-soluble polysaccharides were evaluated in order to find the best drying temperature condition. The results indicates that Midilli model was the fittest model to describe the characteristic of kidney shape G. lucidum in the air circulation drying system and temperature of 50°C was the best drying condition to get highest value of water-soluble polysaccharides.

  15. Controls of Soil Spatial Variability in a Dry Tropical Forest.

    Directory of Open Access Journals (Sweden)

    Sandeep Pulla

    Full Text Available We examined the roles of lithology, topography, vegetation and fire in generating local-scale (<1 km2 soil spatial variability in a seasonally dry tropical forest (SDTF in southern India. For this, we mapped soil (available nutrients, Al, total C, pH, moisture and texture in the top 10 cm, rock outcrops, topography, all native woody plants ≥1 cm diameter at breast height (DBH, and spatial variation in fire frequency (times burnt during the 17 years preceding soil sampling in a permanent 50-ha plot. Unlike classic catenas, lower elevation soils had lesser moisture, plant-available Ca, Cu, Mn, Mg, Zn, B, clay and total C. The distribution of plant-available Ca, Cu, Mn and Mg appeared to largely be determined by the whole-rock chemical composition differences between amphibolites and hornblende-biotite gneisses. Amphibolites were associated with summit positions, while gneisses dominated lower elevations, an observation that concurs with other studies in the region which suggest that hillslope-scale topography has been shaped by differential weathering of lithologies. Neither NO3(--N nor NH4(+-N was explained by the basal area of trees belonging to Fabaceae, a family associated with N-fixing species, and no long-term effects of fire on soil parameters were detected. Local-scale lithological variation is an important first-order control over soil variability at the hillslope scale in this SDTF, by both direct influence on nutrient stocks and indirect influence via control of local relief.

  16. Tunneling behavior of the formosan subterranean termite (isoptera: rhinotermitadae) in dry soil

    Science.gov (United States)

    This study examines the effect of dry soil on tunnel construction by the Formosan subterranean termite, Cptotermes formosanus. Termites did not construct tunnels in dry soil in any of the treatments. Termites only constructed tunnels in moist areas in treatments where the soil was partially moistene...

  17. Associations between soil variables and vegetation structure and composition of Caribbean dry forests

    Science.gov (United States)

    Elvia M. Melendez-Ackerman; Julissa Rojas-Sandoval; Danny S. Fernandez; Grizelle Gonzalez; Hana Lopez; Jose Sustache; Mariely Morales; Miguel Garcia-Bermudez; Susan Aragon

    2016-01-01

    Soil–vegetation associations have been understudied in tropical dry forests when compared to the amount of extant research on this issue in tropical wet forests. Recent studies assert that vegetation in tropical dry forests is highly heterogeneous and that soil variability may be a contributing factor. In this study, we evaluated the relationship between soil variables...

  18. Effects of hot-air and hybrid hot air-microwave drying on drying kinetics and textural quality of nectarine slices

    Science.gov (United States)

    Miraei Ashtiani, Seyed-Hassan; Sturm, Barbara; Nasirahmadi, Abozar

    2018-04-01

    Drying and physicochemical characteristics of nectarine slices were investigated using hot-air and hybrid hot air-microwave drying methods under fixed air temperature and air speed (50 °C and 0.5 m/s, respectively). Microwave power levels for the combined hot air-microwave method were 80, 160, 240, and 320 W. Drying kinetics were analyzed and compared using six mathematical models. For both drying methods the model with the best fitness in explaining the drying behavior was the Midilli-Kucuk model. The coefficient of determination ( R 2), root mean square error (RMSE) and reduced chi square ( χ 2) for this model have been obtained greater than 0.999 and less than 0.006 and 0.0001 for hybrid hot air-microwave drying while those values for hot-air drying were more than 0.999 and less than 0.003 and 0.0001, respectively. Results showed that the hybrid method reduced the drying time considerably and produced products with higher quality. The range of effective moisture diffusivity ( D eff ) of hybrid and hot-air drying was between 8.15 × 10-8 and 2.83 × 10-7 m2/s and 1.27 × 10-8 m2/s, respectively. The total color difference (ΔE) has also been obtained from 36.68 to 44.27 for hybrid method; however this value for hot-air drying was found 49.64. Although reduced microwave power output led to a lower drying rate, it reduced changes in product parameters i.e. total color change, surface roughness, shrinkage and microstructural change and increased hardness and water uptake.

  19. Air-Lubricated Thermal Processor For Dry Silver Film

    Science.gov (United States)

    Siryj, B. W.

    1980-09-01

    Since dry silver film is processed by heat, it may be viewed on a light table only seconds after exposure. On the other hand, wet films require both bulky chemicals and substantial time before an image can be analyzed. Processing of dry silver film, although simple in concept, is not so simple when reduced to practice. The main concern is the effect of film temperature gradients on uniformity of optical film density. RCA has developed two thermal processors, different in implementation but based on the same philosophy. Pressurized air is directed to both sides of the film to support the film and to conduct the heat to the film. Porous graphite is used as the medium through which heat and air are introduced. The initial thermal processor was designed to process 9.5-inch-wide film moving at speeds ranging from 0.0034 to 0.008 inch per second. The processor configuration was curved to match the plane generated by the laser recording beam. The second thermal processor was configured to process 5-inch-wide film moving at a continuously variable rate ranging from 0.15 to 3.5 inches per second. Due to field flattening optics used in this laser recorder, the required film processing area was plane. In addition, this processor was sectioned in the direction of film motion, giving the processor the capability of varying both temperature and effective processing area.

  20. Radon-222 exhalation and its variation in soil air

    International Nuclear Information System (INIS)

    Mochizuki, S.; Sekikawa, T.

    1980-01-01

    A new method has been designed and developed for measuring the concentration of radon in soil air without disturbing the natural condition of the soil. By this method, radon concentrations in the soil air at various points down to a depth of 1 m below the ground are obtained from the concentrations of radium A ( 218 Po) measured in the same air. The radium A concentration is measured by spectrometry of alpha particles from radioactive ions in the soil air. The basic experiments and preliminary observations made in the soil air below the ground confirmed the usefulness of the newly constructed apparatus for measuring the radon concentration in the soil air. Our preliminary observations showed that the radon concentration in the soil air near the surface of the earth varied remarkably before heavy thunderstorms

  1. Deposition rates of atmospheric particulates determined from 210Pb measurements in soils and air

    International Nuclear Information System (INIS)

    Likuku, A. S.; Branford, D.

    2011-01-01

    Deposition rates of atmospheric particles were determined using previously published 210P b data in soils and air. The dry deposition velocities for moorland and woodland soils were 2.2 ± 1.8 and 9 ± 2 mm · s - 1 , respectively. The 210P b concentration in rain was calculated to be 94 ± 10 mBq · L - 1. The large (∼ 4 times) deposition velocities in woodland relative to moorland soils is an indication of the degree of accumulation of particles, and most possibly contaminants within woodland soils, which is of practical importance in the mitigation of pollutant concentrations in urban areas by planting trees. (authors)

  2. Dry soil diurnal quasi-periodic oscillations in soil 222Rn concentrations

    International Nuclear Information System (INIS)

    Tommasone Pascale, F.; De Francesco, S.; Carbone, P.; Cuoco, E.; Tedesco, D.

    2014-01-01

    222 Rn concentrations have been monitored during the dry season in August 2009 and August 2010, in a reworked alluvial-pyroclastic soil of the Pietramelara Plain, in Southern Italy, with the aim of determining the role of atmospheric factors in producing the quasi-periodic oscillations in soil 222 Rn concentrations reported in the literature. In this study we present the results of a detailed analysis and matching of soil 222 Rn concentrations, meteorological and solar parameters where the observed oscillations feature a characteristic behavior with second order build-up and depletion limbs, separated by a daily maximum and minimum. All these features are clearly shown to be tied to sunrise and sunset timings and environmental radiative flux regimes. Furthermore, a significant, and previously unreported, second order correlation (r 2  = 0.73) between daily maximum hourly global radiation and the daily range of soil 222 Rn concentrations has been detected, allowing estimates of the amplitude of these oscillations to be made from estimated or measured solar radiation data. The correlation has been found to be valid even in the presence of persistent patchy daytime cloudiness. In this case a daytime prolongation of the night-time build up stage and an attenuation or even suppression of daytime depletion is observed (a previously unreported effect). Neither soil cracking, nor precipitation, both suggested in some studies as causative factors for these oscillations, during the dry season appear to be necessary in explaining their occurrence. We also report the results of an artificial shading experiment, conducted in August 2009, that further support this conclusion. As soil 222 Rn concentrations during the dry season show a characteristic daily cycle, radon monitoring in soils under these conditions necessarily has to be gauged to the timings of the daily maximum and minimum, as well as to the eventual occurrence of cloudiness and to its related effects, in order to

  3. Evaluation of food drying with air dehumidification system: a short review

    Science.gov (United States)

    Djaeni, M.; Utari, F. D.; Sasongko, S. B.; Kumoro, A. C.

    2018-01-01

    Energy efficient drying for food and agriculture products resulting high quality products has been an important issue. Currently, about 50% of total energy for postharvest treatment was used for drying. This paper presents the evaluation of new approach namely air dehumidification system with zeolite for food drying. Zeolite is a material having affinity to water in which reduced the moisture in air. With low moisture content and relative humidity, the air can improve driving force for drying even at low temperature. Thus, the energy efficiency can be potentially enhanced and the product quality can be well retained. For proving the hypothesis, the paddy and onion have been dried using dehumidified air. As performance indicators, the drying time, product quality, and heat efficiency were evaluated. Results indicated that the drying with zeolite improved the performances significantly. At operating temperature ranging 50 - 60°C, the efficiency of drying system can reach 75% with reasonable product quality.

  4. Pipeline drying using dehumidified air with low dew point temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Syed Younus; Gandhidasan, P.; Al-Farayedhi, A.A. [King Fahd Univ. of Petroleum and Minerals, Mechanical Engineering Dept., Dhahran (Saudi Arabia)

    1998-05-01

    The presence of humidity may be detrimental to the operation of pipelines transporting natural gas or other petroleum products. In particular conditions water solidifies or reacts chemically with hydrocarbons, forming hydrates. Such crystalline substances may cause obstruction of the lines and damage the equipment of the relevant facilities. A procedure for predicting the performance of drying a pipeline using dehumidified air with a low dew point is described in this paper. The mathematical model estimates the time required for the complete removal of moisture in the pipeline for the given operating conditions with simplified assumptions. The governing equations are solved analytically as well as numerically and the results are briefly discussed in the paper. (Author)

  5. Composition of soil air in a profile

    International Nuclear Information System (INIS)

    Victoria, R.L.; Libardi, P.L.; Reichardt, K.

    1976-08-01

    With the objective of understanding microbiological transformations in the soil, measurements of concentration of N 2 , CO 2 , O 2 , and Ar have been made at depths of 30,45,60 and 105 cm on a typical red latosol (Latossol Roxo). The experiment consisted of nitrogen applications in the form of urea and ammonium sulphate, at the rates of 0,40 and 120 Kg N/ha, on bare and cropped plots of snap-beans(PHASEOLUS VULGARIS,L. cultivar goiano precoce.) Soil air samples were collected 20 and 36 days after emergence using special probes and the analysis was performed by mass spectrometry. The results show a variability only of CO 2 and O 2 concentrations remained relatively constant

  6. Dynamics of soil water evaporation during soil drying: laboratory experiment and numerical analysis.

    Science.gov (United States)

    Han, Jiangbo; Zhou, Zhifang

    2013-01-01

    Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3.

  7. Dynamics of Soil Water Evaporation during Soil Drying: Laboratory Experiment and Numerical Analysis

    Science.gov (United States)

    Han, Jiangbo; Zhou, Zhifang

    2013-01-01

    Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. PMID:24489492

  8. Air-soil exchange of PCBs: levels and temporal variations at two sites in Turkey.

    Science.gov (United States)

    Yolsal, Didem; Salihoglu, Güray; Tasdemir, Yücel

    2014-03-01

    Seasonal distribution of polychlorinated biphenyls (PCBs) at the air-soil intersection was determined for two regions: one with urban characteristics where traffic is dense (BUTAL) and the other representing the coastal zone (Mudanya). Fifty-one air and soil samples were simultaneously collected. Total PCB (Σ82 PCB) levels in the soil samples collected during a 1-year period ranged between 105 and 7,060 pg/g dry matter (dm) (BUTAL) and 110 and 2,320 pg/g dm (Mudanya). Total PCB levels in the gaseous phase were measured to be between 100 and 910 pg/m(3) (BUTAL) and 75 and 1,025 pg/m(3) (Mudanya). Variations in the concentrations were observed depending on the season. Though the PCB concentrations measured in the atmospheres of both regions in the summer months were high, they were found to be lower in winter. However, while soil PCB levels were measured to be high at BUTAL during summer months, they were found to be high during winter months in Mudanya. The direction and amount of the PCB movement were determined by calculating the gaseous phase change fluxes at air-soil intersection. While a general PCB movement from soil to air was found for BUTAL, the PCB movement from air to soil was calculated for the Mudanya region in most of the sampling events. During the warmer seasons PCB movement towards the atmosphere was observed due to evaporation from the soil. With decreases in the temperature, both decreases in the number of PCB congeners occurring in the air and a change in the direction of some congeners were observed, possibly caused by deposition from the atmosphere to the soil. 3-CB and 4-CB congeners were found to be dominant in the atmosphere, and 4-, 5-, and 6-CBs were found to dominate in the surface soils.

  9. The Effect of Drying-Wetting Cycle’s Repetition to the Characteristic of Natural and Stabilization Residual Soils Jawa Timur - Indonesia

    Science.gov (United States)

    Muntaha, M.

    2017-11-01

    Indonesia, which located in tropical region, continuously undergoes wetting and drying cycles due to the changeable seasons. An important role in activating the clay minerals on tropical residual soils is the main factor that affects the static and dynamic properties, such as: volume change, soil suction and dynamic modulus. The purpose of this paper is to evaluate the effect of drying-wetting cycles repetition on volume change, soil suction and mechanical characteristics of natural and stabilization of residual soils from Jawa Timur - Indonesia. The natural undisturbed and stabilized residual soil sample was naturally and gradually dried up with air to 25%, 50%, 75%, and 100 % of the initial water content. The wetting processes were carried out with the gradual increment water content of 25 %(wsat - wi), 50 %(wsat - wi), 75 %(wsat - wi), up to 100 %(wsat - wi). The Direct Shear test is used to measure the mechanic properties, and Whatman filter paper No. 42 is used to measure the soil suction. The drying-wetting processes were carried out for 1, 2, 4, and 6 cycles. The laboratory test results showed that, the void ratio decreased, the unit weight, cohesion and the internal friction angle were increasing due to stabilization. Drying-wetting cycle repetition reduces void ratio, negative pore-water pressure, cohesion and internal friction angle of natural and stabilized soils. Briefly, the decreased of mechanical soil properties was proven from the physical properties change observation.

  10. Analysis of the average daily radon variations in the soil air

    International Nuclear Information System (INIS)

    Holy, K.; Matos, M.; Boehm, R.; Stanys, T.; Polaskova, A.; Hola, O.

    1998-01-01

    In this contribution the search of the relation between the daily variations of the radon concentration and the regular daily oscillations of the atmospheric pressure are presented. The deviation of the radon activity concentration in the soil air from the average daily value reaches only a few percent. For the dry summer months the average daily course of the radon activity concentration can be described by the obtained equation. The analysis of the average daily courses could give the information concerning the depth of the gas permeable soil layer. The soil parameter is determined by others method with difficulty

  11. Aroma changes in fresh bell peppers (Capsicum annuum) after hot-air drying.

    NARCIS (Netherlands)

    Luning, P.A.; Yuksel, D.; Vuurst de Vries, van R.; Roozen, J.P.

    1995-01-01

    The aroma of fresh and hot-air dried bell peppers (Capsicum annuum) was evaluated by sensory and instrumental methods. Hot-air drying decreased levels of the odor compounds (Z)-3-hexenal, 2-heptanone, (Z)-2-hexenal, (E)-2-hexenal, hexanol, (Z)-3-hexanol, (E)-2-hexenol, and linalool, which have

  12. Soil Effects on Forest Structure and Diversity in a Moist and a Dry Tropical Forest

    NARCIS (Netherlands)

    Peña-Claros, M.; Poorter, L.; Alarcon, A.; Blate, G.; Choque, U.; Fredericksen, T.S.; Justiniano, J.; Leaño, C.; Licona, J.C.; Pariona, W.; Putz, F.E.; Quevedo, L.; Toledo, M.

    2012-01-01

    Soil characteristics are important drivers of variation in wet tropical forest structure and diversity, but few studies have evaluated these relationships in drier forest types. Using tree and soil data from 48 and 32 1 ha plots, respectively, in a Bolivian moist and dry forest, we asked how soil

  13. Seasonal variation in soil and plant water potentials in a Bolivian tropical moist and dry forest

    NARCIS (Netherlands)

    Markesteijn, L.; Iraipi, J.; Bongers, F.; Poorter, L.

    2010-01-01

    We determined seasonal variation in soil matric potentials (¿soil) along a topographical gradient and with soil depth in a Bolivian tropical dry (1160 mm y-1 rain) and moist forest (1580 mm y-1). In each forest we analysed the effect of drought on predawn leaf water potentials (¿pd) and drought

  14. OPTIMIZATION OF MICROWAVE AND AIR DRYING CONDITIONS OF QUINCE (CYDONIA OBLONGA, MILLER USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Cem Baltacioglu

    2015-03-01

    Full Text Available Effects of slice thickness of quince (Cydonia oblonga Miller , microwave incident power and air drying temperature on antioxidant activity and total phenolic content of quince were investigated during drying in microwave and air drying. Optimum conditions were found to be: i for microwave drying, 285 W and 4.14 mm thick (maximum antioxidant activity and 285 W and 6.85 mm thick (maximum total phenolic content, and ii for air drying, 75 ºC and 1.2 mm thick (both maximum antioxidant activity and total phenolic content. Drying conditions were optimized by using the response surface methodology. 13 experiments were carried out considering incident microwave powers from 285 to 795 W, air temperature from 46 to 74 ºC and slice thickness from 1.2 to 6.8 mm.

  15. Influence of drying conditions on the effective diffusivity and activation energy during convective air and vacuum drying of pumpkin

    Directory of Open Access Journals (Sweden)

    Liliana SEREMET (CECLU

    2015-12-01

    Full Text Available The main purpose of the work is to investigate the efficiency of convective air and vacuum processing on pumpkin drying kinetics. The pumpkin samples were of two different geometrical shapes (cylinder and cube and were dried in a laboratory scale hot air dryer using some specific parameters (constant air velocity of 1.0 m/s, three different temperatures 50, 60 and 70ºC suited to relative humidity (RH values of 9.8, 6.5, and 5.4% respectively. The vacuum drying was led at constant pressures of 5 kPa and accordance temperatures of 50, 60 and 70ºC. Moisture transfer from pumpkin slices was described by applying Fick’s diffusion model. Temperature dependence of the effective diffusivity was described by the Arrhenius-type equation. Cylindrical samples have a slightly better behaviour compared to cubic samples, due to the disposition of the tissues, and the mass and thermic transfer possibilities. Analysing the results of both drying methods, it was deduced that the most efficient method is convective air drying at 70ºC.

  16. Effect of wetting-drying cycles on soil desiccation cracking behaviour

    Directory of Open Access Journals (Sweden)

    Tang Chao-Sheng

    2016-01-01

    Full Text Available Better understanding the desiccation cracking process is essential in analysing drought effects on soil hydraulic and mechanical properties through consideration of the atmosphere-ground interaction. Laboratory tests were conducted to investigate the consequence of wetting-drying cycles on the initiation and propagation characteristics of desiccation cracks on soil surface. Initially saturated slurry specimens were prepared and subjected to five subsequent wetting-drying cycles. Image processing technique was employed to quantitatively analyze the morphology characteristics of crack patterns formed during each drying path. The results show that the desiccation cracking behaviour of soil is significantly affected by the wetting-drying cycles. Before the third wetting-drying cycle is reached, the surface crack ratio and the average crack width increases while the average clod area decreases with increasing the number of wetting-drying cycles. The number of intersections and crack segments per unit area reaches the peak values after the second wetting-drying cycle. After the third wetting-drying cycle is reached, the effect of increasing wetting-drying cycles on crack patterns is insignificant. Moreover, it is observed that the applied wetting-drying cycles are accompanied by a continual reconstruction of soil structure. The initial homogenous slurry structure is completely replaced with aggregated structure after the third cycles, and a significant increase in the inter-aggregate porosity can be observed.

  17. Reduced heat stress in offices in the tropics using solar powered drying of the supply air

    DEFF Research Database (Denmark)

    Gunnarsen, Lars; Santos, A M B

    2002-01-01

    air may facilitate personal cooling by increased evaporation of sweat. Heat acclimatized people with efficient sweating may in particular benefit from this cooling. A prototype solar powered supply system for dried-only air was made. Air from the system was mixed with room air, heated to six different...... content of room air, temperature of supply air and moisture content of supply air was developed based on the experiments. Reduction of moisture content in the supply air by 1.6 g/kg had the same effect as lowering the operative temperature by 1 degree C. The solar-powered system for supplying dry air...... is a low-cost alternative to traditional air conditioning in hot and humid regions....

  18. Estimation of bare soil surface temperature from air temperature and ...

    African Journals Online (AJOL)

    Soil surface temperature has critical influence on climate, agricultural and hydrological activities since it serves as a good indicator of the energy budget of the earth's surface. Two empirical models for estimating soil surface temperature from air temperature and soil depth temperature were developed. The coefficient of ...

  19. Oxidation behaviour of U2Ti alloy in dry air

    International Nuclear Information System (INIS)

    Roy, S.P.; Gupta, N.K.; Jat, Ram Avtar; Parida, S.C.; Mukerjee, S.K.

    2016-01-01

    U 2 Ti alloy is being considered as promising storage material for storage of hydrogen isotopes. However, the absorption capacity of this reactive alloy can be affected due to presence of oxygen in the process gas. Hence, it is necessary to know the kinetic of this alloy in presence of oxygen. In this study, U 2 Ti alloy was prepared by arc melting method followed by vacuum annealing. The alloy was characterized by XRD, SEM and EDX methods. The isothermal oxidation behaviour of U 2 Ti alloy was investigated in the temperature range of 548-623 K in dry air for 24 hours by using thermo gravimetric technique. The oxidation curves are shown. The oxidation curves were analysed using the rate equation: (Δm/a) n = kt, where, (Δm/a) is the mass gain per unit area, n is the power exponent, k is the rate constant and t is time in (seconds). Analysis of the results shows that the oxidation reaction follows linear rate law (n ~ 1). Using the linear rate law, the rate constant (k) of oxidation reaction was evaluated at each temperature in the range 548-623 K. The variation of (ln k) with reciprocal temperature is shown. The activation energy of this oxidation reaction in the temperature range 548-623 K was calculated using the Arrhenius equation and found to be 76 kJ/mol. The XRD analysis of the oxidation products was found to be U 3 O 8 and TiO 2 . (author)

  20. Effect of Turmerin on Endothelial Denudation by Air Drying

    Directory of Open Access Journals (Sweden)

    A. K. Markov

    2002-09-01

    Full Text Available Abstract: The objective of this study is to determine if arterial endothelial injury can be attenuated by local application of 80 μg/ml turmerin at the site of injury and by oral administration of the same dose. Anesthetized Lewis rats (n =12 weighing 200 ± 4.0 gms randomly were assigned to two groups. After 5 min of air drying a segment of right carotid artery, six rats were treated locally 80μg/ml with turmerin and the rest were treated with 0.9% NaCl. Turmerin was then administered by gavage (80 μg every 24 hrs for 14 days. Animals were sacrificed on day 14 and the carotid artery removed from the injured site for histological analysis and serum collected for lipid peroxidation analysis by measuring malondialdehyde (MDA and conjugated dienes. This study showed no proliferation in the intima of one rat out of six rats treated with turmerin while there was significant variation between the treated rats and the controls. MDA for control was 0.593±0.02 nanomoles/ml while turmerin was 0.187±0.04 (p≤0.01; conjugated diene for control was 0.402±0.03 nanomoles/ml while turmerin was 0.212±0.04 nanomoles/ml (p ≤0.05. Although there was significant reduction in serum peroxidation activity, the histological findings indicate that attenuation of carotid artery injury may involve other factors than decreased lipid peroxidation.

  1. Conceptual Modeling of the Influence of Wetting and Drying Cycles on Soil Aggregation and Stabilization

    Science.gov (United States)

    Albalasmeh, A. A.; Ghezzehei, T.

    2011-12-01

    Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and around soil. The interaction of environmental and biotic agents influences the physical condition of the soil, particularly through soil structural evolution. Wetting and drying cycles are important environmental processes known to enhance aggregation, while clay minerals, sesquioxides and soil organic matter (SOM) are the soil solids most involved in soil structural development. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We will present results of the effect of particle size, number of wetting and drying cycles, viscosity, molecule length and concentration of suspended and/or dissolved cementing agents on soil aggregation and stabilization.

  2. Soil aggregate formation: the role of wetting-drying cycles in the genesis of interparticle bonding

    Science.gov (United States)

    Albalasmeh, Ammar; Ghezzehei, Teamrat

    2013-04-01

    Soil structure influences many soil properties including aeration, water retention, drainage, bulk density, and resistance to erosion and indirectly influences most biological and chemical processes that occur in and around soil. In nature, soil is continually exposed to wetting (e.g., rainfall and diffusive flow) and drying (e.g., evaporation, diffusive flow and plant uptake). These natural wetting and drying cycles of soils are physical events that profoundly affect the development of soil structure, aggregate stability, carbon (C) flux and mineralization. We hypothesize that drying of capillary water transports suspended and/or dissolved cementing agents toward inter-particle contacts and eventually deposits part of the colloidal mass forming inter-particle bonds. Here, we will show the role of wetting and drying cycles on soil aggregation and stabilization and how these cycles transport and deposit organic cementing agents at the inter-particle contact. We found that aggregates of sand and silt particles can be formed by subjecting loose particles to wetting-drying cycles in the presence of dilute solutions of organic matter that mimic root or microbial exudates. Moreover, majority of the organic matter was deposited in the contact region between the sand particles, where the water accumulates during drying. The model predictions and aggregate stability measurements are supported by scanning electron micrographs that clearly show the process of aggregate formation.

  3. Hot-air drying of purslane ( Portulaca oleracea L.)

    Science.gov (United States)

    Doymaz, İbrahim

    2013-06-01

    Drying characteristics of purslane was experimentally studied in a cabinet dryer. The experimental drying data were fitted best to Modified Henderson and Pabis and Midilli et al. models apart from other models to predict the drying kinetics. The effective moisture diffusivity varied from 1.12 × 10-9 to 3.60 × 10-9 m2/s over the temperature range studied and activation energy was 53.65 kJ/mol.

  4. Soil-air exchange of organochlorine pesticides in the Southern United States

    International Nuclear Information System (INIS)

    Bidleman, Terry F.; Leone, Andi D.

    2004-01-01

    Soil samples were collected from 30 farms in Alabama, Louisiana and Texas during 1999-2000 to determine residues of organochlorine pesticides (OCPs). One or more of the DDT compounds (p,p'-DDT, o,p'-DDT, p,p'-DDD, p,p'-DDE, o,p'-DDE) was above the quantitation limit (0.1 ng g -1 dry weight) in every soil, and toxaphene was above the quantitation limit (3 ng g -1 ) in 26 soils. Chlordanes, dieldrin and hexachlorocyclohexane (HCH) isomers occurred less frequently (quantitation limits 0.1 ng g -1 for dieldrin and 0.05 ng g -1 for chlordanes and HCHs). OCPs were measured in air at 40 cm above the soil at selected farms to investigate soil-air partitioning. Concentrations of OCPs in air were positively and significantly (P s and f a ) for samples with quantifiable residues in both compartments. The fugacity fraction ((f s )/(f s +f a ))=0.5 at equilibrium and is 0.5 for net deposition and net volatilisation, respectively. Fugacity fractions varied greatly for different soil-air pairs, reflecting generally disequilibrium conditions. Mean fugacity fractions indicated near-equilibrium for some OCPs (p,p'-DDE, chlordanes, trans-nonachlor and dieldrin) and net volatilisation for others (p,p'-DDT, o,p'-DDT, toxaphene, γ-HCH). Chiral analysis showed that enantioselective degradation of (+) or (-) o,p'-DDT in soil was accompanied by enrichment or depletion of the corresponding enantiomers in the overlying air, although there appeared to be some dilution by racemic o,p'-DDT from regional air transport. - Old pesticide residues in agricultural soils continue to be emitted into the atmosphere

  5. Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-07-28

    Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO2 Brayton cycle is that it enables dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately

  6. Effect of drying on the desorption of diuron and terbuthylazine from natural soils.

    Science.gov (United States)

    Lennartz, Bernd; Louchart, Xavier

    2007-03-01

    This work was initiated to study the effects of climate induced soil water status variations which can reach extreme values under natural conditions on the sorption process of hydrophobic organic compounds. Based on the classical slurry batch methodology an approach is developed that allows the fast and careful complete drying of soil suspensions (microwave technique). Classical adsorption experiments were followed by three desorption steps with and without drying cycles. Drying and re-wetting enhanced the sorption-desorption hysteresis and Freundlich adsorption coefficients increased from 5.9 to 16 and 5.2 to 21 over three drying cycles for diuron and terbuthylazine respectively. Assuming the validity of a dual stage adsorption process, model evaluation suggests that drying is as a shrinking-like process leading to conformational changes of the dominant sorbent (soil organic matter) which restrict the intra-micro-particle diffusion. Rewetting only leads to a partial recovery of the diffusional pore space.

  7. Drying shrinkage problems in high-plastic clay soils in Oklahoma.

    Science.gov (United States)

    2013-08-01

    Longitudinal cracking in pavements due to drying shrinkage of high-plastic subgrade soils has been a major : problem in Oklahoma. Annual maintenance to seal and repair these distress problems costs significant amount of : money to the state. The long...

  8. Microbial responses of forest soil to moderate anthropogenic air pollution - a large scale field survey

    International Nuclear Information System (INIS)

    Vanhala, P.; Kiikkila, O.; Fritze, H.

    1996-01-01

    There is a need to introduce soil microbiological methods into long term ecological monitoring programs. For this purpose we studied the impact of moderate anthropogenic air pollution in polluted and less polluted area districts, forest site types Calluna (CT), Vaccinium (VT) and Myrtillus (MT) and the amount of organic matter, measured as carbon content on the soil respiration activity and the ATP content. The main sources of local air pollutants (SO 2 and NO x ) in the polluted area district were from the capital region and an oil refinery. Humus (F/H-layer) and the underlying 0 to 5 cm mineral soil samples were collected from 193 study plots located in the 5300 km 2 study area. We found that the soil respiration rate in humus layer samples was lower in the polluted area district compared to the less polluted one (16.0 and 19.5μL CO 2 h -1 g -1 dw, respectively), but the difference occurred only in the dry, coarse-textured CT forest site type. The mineral soil respiration rate and the mineral soil and humus layer ATP content were not affected by the air pollution. Most of the variations of the biological variables were explained primarily by the soil carbon content, secondly by the forest site type and thirdly by the area division. 38 refs., 1 fig., 6 tabs

  9. Soil water retention curves of remoulded clay on drying and wetting paths

    International Nuclear Information System (INIS)

    Zhang Xiwei; Zhang Jian

    2010-01-01

    The present research focuses on the laboratory measurement of the Soil Water Retention Curve (SWRC), that expresses the relationship between water content (gravimetric or volumetric) or degree of saturation and soil suction. The SWRC plays an important role in an unsaturated soil mechanics framework and is required for the numerical modelling of any process of flow and transport in unsaturated soil problems, already as a part of constitutive model of unsaturated soil. Six remoulded London Clay samples were performed SWRC testing on the drying and wetting path, meanwhile measurement the volume change. The effect of initial water content and various drying/wetting paths were considered in the tests. The results of SWRC show that hysteretic characteristic in boundary drying/wetting curve, the water holding capacity was increased due to the increase of the initial water content. The shape of the SWRC strongly depended on the volume change. (authors)

  10. Study of 222Rn variations in the soil air

    International Nuclear Information System (INIS)

    Holy, K.; Boehm, R.; Matos, M.; Polaskova, A.; Hola, O.

    1998-01-01

    A significant source of radon in the indoor atmosphere is represented by 222 Rn in the soil air, ie., by the fraction of radon atoms produced by alpha decay of 226 Ra in soil grains that escaped into soil pores. In the paper the results are presented of a three year monitoring of radon in soil air, using a 125 ml Lucas type scintillation cell. Radon concentration depth profiles in the soil in various seasons of the year were also measured, and saturated concentration of radon in soil air was found at a depth of about 2 m. Monthly variations in the radon concentration were observed over several months and the possible causes of the variations are discussed. Daily courses of radon concentration were also measured and the results are presented. (A.K.)

  11. Measurement of 222Rn in soil concentrations in interstitial air

    International Nuclear Information System (INIS)

    Duenas, C.; Fernandez, M.C.; Carretero, J.; Liger, E.

    1996-01-01

    Measurements of 222 Rn soil concentrations were made by inserting stainless-steel sampling tubes into the soil. The samples of the soil interstitial air were taken in to pre-evacuated 1 L glass flasks. The glass flasks are cylindrical and coated with a film of ZnS(Ag). 222 Rn was measured by counting the alpha particles emitted by 222 Rn and its daughter products, 218 Po and 214 Bi, when they reached radioactive equilibrium. Measurements of 222 Rn gas concentrations in the soil air interstices by the method at different depths were used to calculate the diffusion coefficient of the 222 Rn in the soil air. This study has been carried out for diverse soils. (Author)

  12. The Impact of Dry Midlevel Air on Hurricane Intensity in Idealized Simulations with No Mean Flow

    Science.gov (United States)

    Braun, Scott A.; Sippel, Jason A.; Nolan, David S.

    2012-01-01

    This study examines the potential negative influences of dry midlevel air on the development of tropical cyclones (specifically, its role in enhancing cold downdraft activity and suppressing storm development). The Weather Research and Forecasting model is used to construct two sets of idealized simulations of hurricane development in environments with different configurations of dry air. The first set of simulations begins with dry air located north of the vortex center by distances ranging from 0 to 270 km, whereas the second set of simulations begins with dry air completely surrounding the vortex, but with moist envelopes in the vortex core ranging in size from 0 to 150 km in radius. No impact of the dry air is seen for dry layers located more than 270 km north of the initial vortex center (approximately 3 times the initial radius of maximum wind). When the dry air is initially closer to the vortex center, it suppresses convective development where it entrains into the storm circulation, leading to increasingly asymmetric convection and slower storm development. The presence of dry air throughout the domain, including the vortex center, substantially slows storm development. However, the presence of a moist envelope around the vortex center eliminates the deleterious impact on storm intensity. Instead, storm size is significantly reduced. The simulations suggest that dry air slows intensification only when it is located very close to the vortex core at early times. When it does slow storm development, it does so primarily by inducing outward- moving convective asymmetries that temporarily shift latent heating radially outward away from the high-vorticity inner core.

  13. Persistent Soil Seed Banks for Natural Rehabilitation of Dry Tropical Forests in Northern Ethiopia

    OpenAIRE

    Gebrehiwot, K.; Heyn, M.; Reubens, B.; Hermy, M.; Muys, B.

    2007-01-01

    Dry tropical forests are threatened world-wide by conversion to grazing land, secondary forest, savannah or arable land. In Ethiopia, natural dry forest cover has been decreasing at an alarming rate over the last decennia and has reached a critical level. Efforts like the rehabilitation of dry forests to curb this ecological degradation, need a stronger scientific basis than currently available. The aim of the present research was to test the hypothesis whether soil seed banks can contribute ...

  14. Effect of N, P and K Humates on Dry Matter of Zea mays and Soil

    African Journals Online (AJOL)

    Sharjeel Ahmad

    may only be applicable to similar acid soils. The outcome of this study may contribute to the improvement of urea N use efficiency as well as reducing environmental pollution. Key words: Humic acids, fulvic acids, triple superphosphate, muriate of potash, soil exchangeable ammonium, available nitrate, Zea mays, dry matter.

  15. Microbial responses to carbon and nitrogen supplementation in an Antarctic dry valley soil

    DEFF Research Database (Denmark)

    Dennis, P. G.; Sparrow, A. D.; Gregorich, E. G.

    2013-01-01

    The soils of the McMurdo Dry Valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain active biological communities that contribute to the biogeochemical processes. We have used ester-linked fatty acid (ELFA) analysis to investigate the effects of additions of carbon...... and nitrogen in glucose and ammonium chloride, respectively, on the soil microbial community in a field experiment lasting three years in the Garwood Valley. In the control treatment, the total ELFA concentration was small by comparison with temperate soils, but very large when expressed relative to the soil...... organic carbon concentration, indicating efficient conversion of soil organic carbon into microbial biomass and rapid turnover of soil organic carbon. The ELFA concentrations increased significantly in response to carbon additions, indicating that carbon supply was the main constraint to microbial...

  16. Effect of Adding Sugarcane Bagasse and Filter Cake and Wetting and Drying Cycles on Pre-Compaction Stress of Soil

    Directory of Open Access Journals (Sweden)

    Z Nemati

    2018-03-01

    replications. A composite disturbed sample of topsoil (0–200 mm deep of a silty clay loam soil was collected from Isfahan province (32 31.530 N; 51 49.40E in center of Iran. The mean annual precipitation and temperature of the region are about 160 mm and 16 C, respectively. Sugarcane residues (bagasse and filter cake were obtained from the sugarcane fields in Ahvaz, Khuzestan province (Iran. The samples were air-dried and passed through a 2-mm sieve. Soil treated by bagasse and filter cake in different rates was poured and knocked lightly into cylinders with diameter and height of 25 and 8 cm, respectively. Large air-dry disturbed soil samples were prepared and some of them were exposed to five wetting and drying cycles. Finally, the soil surface was covered by a plastic sheet and was left overnight in the laboratory (for 24 hours to enable the moisture to equilibrate. The loading tests were performed the next day. The pre-compaction stress was determined by plate sinkage test (PST. The loading test for PST was performed using CBR apparatus. The compression for PST was continuous at the same constant displacement rate of the CBR (i.e. 1 mm min-1. Determination of the σpc was done using Casagrande’s graphical estimation procedure (Casagrande, 1936 in a program written in MatLab software. Results and Discussion The results showed that σpc was significantly decreased by adding residues to the soil at both water contents, and with/without wetting and drying process. For untreated treatments (control, the σpc decreased with increasing water content. Although σpc decreased with adding the residues to the soil, however, the effect of residue types and percentages and soil water content on σpc was not significant for the soil samples treated with residues. Conclusions In order to prevent re-compaction of the soil and improve its structure, it is suggested that traffic control system with permanent routes for the movement of machinery to be used in sugar cane plantations and

  17. A Numerical Assessment of the Air Flow Behaviour in a Conventional Compact Dry Kiln

    OpenAIRE

    Paulo Zdanski; Daniel Possamai; Miguel Vaz Jr.

    2015-01-01

    Convective drying is the most common drying strategy used in timber manufacturing industries in the developing world. In convective drying, the reduction rate of the moisture content is directly affected by the flow topology in the inlet and exit plenums and the air flow velocity in the channels formed by timber layers.Turbulence, boundary layer separation, vortex formation and recirculation regions are flow features that are intrinsically associated with the kiln geometry, which in turn dict...

  18. Mercury Exchange at the Air-Water-Soil Interface: An Overview of Methods

    Directory of Open Access Journals (Sweden)

    Fengman Fang

    2002-01-01

    Full Text Available An attempt is made to assess the present knowledge about the methods of determining mercury (Hg exchange at the air-water-soil interface during the past 20 years. Methods determining processes of wet and dry removal/deposition of atmospheric Hg to aquatic and terrestrial ecosystems, as well as methods determining Hg emission fluxes to the atmosphere from natural surfaces (soil and water are discussed. On the basis of the impressive advances that have been made in the areas relating to Hg exchange among air-soil-water interfaces, we analyzed existing problems and shortcomings in our current knowledge. In addition, some important fields worth further research are discussed and proposed.

  19. Non-isothermal processes during the drying of bare soil: Model Development and Validation

    Science.gov (United States)

    Sleep, B.; Talebi, A.; O'Carrol, D. M.

    2017-12-01

    Several coupled liquid water, water vapor, and heat transfer models have been developed either to study non-isothermal processes in the subsurface immediately below the ground surface, or to predict the evaporative flux from the ground surface. Equilibrium phase change between water and gas phases is typically assumed in these models. Recently, a few studies have questioned this assumption and proposed a coupled model considering kinetic phase change. However, none of these models were validated against real field data. In this study, a non-isothermal coupled model incorporating kinetic phase change was developed and examined against the measured data from a green roof test module. The model also incorporated a new surface boundary condition for water vapor transport at the ground surface. The measured field data included soil moisture content and temperature at different depths up to the depth of 15 cm below the ground surface. Lysimeter data were collected to determine the evaporation rates. Short and long wave radiation, wind velocity, air ambient temperature and relative humidity were measured and used as model input. Field data were collected for a period of three months during the warm seasons in south eastern Canada. The model was calibrated using one drying period and then several other drying periods were simulated. In general, the model underestimated the evaporation rates in the early stage of the drying period, however, the cumulative evaporation was in good agreement with the field data. The model predicted the trends in temperature and moisture content at the different depths in the green roof module. The simulated temperature was lower than the measured temperature for most of the simulation time with the maximum difference of 5 ° C. The simulated moisture content changes had the same temporal trend as the lysimeter data for the events simulated.

  20. MEASUREMENT OF INDOOR AIR EMISSIONS FROM DRY-PROCESS PHOTOCOPY MACHINES

    Science.gov (United States)

    The article provides background information on indoor air emissions from office equipment, with emphasis on dry-process photocopy machines. The test method is described in detail along with results of a study to evaluate the test method using four dry-process photocopy machines. ...

  1. Mass transfer characteristics of bisporus mushroom ( Agaricus bisporus) slices during convective hot air drying

    Science.gov (United States)

    Ghanbarian, Davoud; Baraani Dastjerdi, Mojtaba; Torki-Harchegani, Mehdi

    2016-05-01

    An accurate understanding of moisture transfer parameters, including moisture diffusivity and moisture transfer coefficient, is essential for efficient mass transfer analysis and to design new dryers or improve existing drying equipments. The main objective of the present study was to carry out an experimental and theoretical investigation of mushroom slices drying and determine the mass transfer characteristics of the samples dried under different conditions. The mushroom slices with two thicknesses of 3 and 5 mm were dried at air temperatures of 40, 50 and 60 °C and air flow rates of 1 and 1.5 m s-1. The Dincer and Dost model was used to determine the moisture transfer parameters and predict the drying curves. It was observed that the entire drying process took place in the falling drying rate period. The obtained lag factor and Biot number indicated that the moisture transfer in the samples was controlled by both internal and external resistance. The effective moisture diffusivity and the moisture transfer coefficient increased with increasing air temperature, air flow rate and samples thickness and varied in the ranges of 6.5175 × 10-10 to 1.6726 × 10-9 m2 s-1 and 2.7715 × 10-7 to 3.5512 × 10-7 m s-1, respectively. The validation of the Dincer and Dost model indicated a good capability of the model to describe the drying curves of the mushroom slices.

  2. Potential of roof-integrated solar collectors for preheating air at drying facilities in Northern Thailand

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Franz; Nagle, Marcus; Leis, Hermann; Mueller, Joachim [Institute of Agricultural Engineering 440e, University of Hohenheim, Garbenstrasse 9, 70599 Stuttgart (Germany); Janjai, Serm [Department of Physics, Silpakorn University, Nakhon Pathom (Thailand); Mahayothee, Busarakorn [Department of Food Technology, Silpakorn University, Nakhon Pathom (Thailand); Haewsungcharoen, Methinee [Department of Food Engineering, Chiang Mai University, Chiang Mai (Thailand)

    2009-07-15

    Longan is one of the most widely cropped fruits in Northern Thailand, where a significant amount of the annual harvest is commercially dried and exported as a commodity. Liquefied petroleum gas is generally used as the energy source for heating the drying air, but concern is growing as fuel prices are expected to increase for the foreseeable future. Meanwhile, with the ample solar radiation in Thailand, the roofs of drying facilities could be adapted to serve as solar collectors to preheat the drying air, thus reducing the energy requirement from fossil fuels. In this study, a simulation program for a flat-plate solar air heater was used to estimate the potential to preheat drying air given the conditions of several longan drying facilities. Results showed that solar collectors can replace up to 19.6% of the thermal energy demand during the drying season. Bigger collectors and smaller air channels result in more useful heat, but attention has to be paid to costs and pressure drop, respectively. Annual monetary savings can reach up to THB 56,000 ({approx}US$ 1800 at US$ 1 THB 31). (author)

  3. Water loss at normal enamel histological points during air drying at room temperature.

    Science.gov (United States)

    De Medeiros, R C G; De Lima, T A S; Gouveia, C R; De Sousa, F B

    2013-06-01

    This in vitro study aimed to quantify water loss at histological points in ground sections of normal enamel during air drying at room temperature (25°C) and relative humidity of 50%. From each of 10 ground sections of erupted permanent human normal enamel, three histological points (n = 30) located at 100, 300 and 500 μm from enamel surface and along a transversal following prisms paths were characterized regarding the mineral, organic and water volumes. Water loss during air drying was from 0 to 48 h. Drying occurred with both falling and constant-drying rates, and drying stabilization times (Teq ) ranged from 0.5 to 11 h with a mean 0.26 (±0.12)% weight loss. In some samples (n = 5; 15 points), Teq increased as a function of the distance from the enamel surface, and drying occurred at an apparent diffusion rate of 3.47 × 10⁻⁸ cm² s⁻¹. Our data provide evidence of air drying resulting in air replacing enamel's loosely bound water in prisms sheaths following a unidirectional water diffusion rate of 3.47 × 10⁻⁸ cm² s⁻¹ (from the original enamel surface inward), not necessarily resulting in water evaporating directly into air, with important implications for transport processes and optical and mechanical properties. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  4. Effect of drying on the desorption of diuron and terbuthylazine from natural soils

    Energy Technology Data Exchange (ETDEWEB)

    Lennartz, Bernd [Institute for Land Use, Rostock University, Justus-von-Liebig-Weg 6, D-18051 Rostock (Germany)]. E-mail: bernd.lennartz@uni-rostock.de; Louchart, Xavier [Laboratory on Interactions between Soils, Agrosystems and Hydrosystems (LISAH), National Institute for Agricultural Research (INRA), 2 place Viala, 34060 Montpellier Cedex 1 (France)

    2007-03-15

    This work was initiated to study the effects of climate induced soil water status variations which can reach extreme values under natural conditions on the sorption process of hydrophobic organic compounds. Based on the classical slurry batch methodology an approach is developed that allows the fast and careful complete drying of soil suspensions (microwave technique). Classical adsorption experiments were followed by three desorption steps with and without drying cycles. Drying and re-wetting enhanced the sorption-desorption hysteresis and Freundlich adsorption coefficients increased from 5.9 to 16 and 5.2 to 21 over three drying cycles for diuron and terbuthylazine respectively. Assuming the validity of a dual stage adsorption process, model evaluation suggests that drying is as a shrinking-like process leading to conformational changes of the dominant sorbent (soil organic matter) which restrict the intra-micro-particle diffusion. Rewetting only leads to a partial recovery of the diffusional pore space. - Drying of soil samples increased the binding of herbicidal compounds which is interpreted as a reduction of diffusional mass transfer into and out of the soil organic matter.

  5. Effect of drying on the desorption of diuron and terbuthylazine from natural soils

    International Nuclear Information System (INIS)

    Lennartz, Bernd; Louchart, Xavier

    2007-01-01

    This work was initiated to study the effects of climate induced soil water status variations which can reach extreme values under natural conditions on the sorption process of hydrophobic organic compounds. Based on the classical slurry batch methodology an approach is developed that allows the fast and careful complete drying of soil suspensions (microwave technique). Classical adsorption experiments were followed by three desorption steps with and without drying cycles. Drying and re-wetting enhanced the sorption-desorption hysteresis and Freundlich adsorption coefficients increased from 5.9 to 16 and 5.2 to 21 over three drying cycles for diuron and terbuthylazine respectively. Assuming the validity of a dual stage adsorption process, model evaluation suggests that drying is as a shrinking-like process leading to conformational changes of the dominant sorbent (soil organic matter) which restrict the intra-micro-particle diffusion. Rewetting only leads to a partial recovery of the diffusional pore space. - Drying of soil samples increased the binding of herbicidal compounds which is interpreted as a reduction of diffusional mass transfer into and out of the soil organic matter

  6. Do drying and rewetting cycles modulate effects of sulfadiazine spiked manure in soil?

    Science.gov (United States)

    Jechalke, Sven; Radl, Viviane; Schloter, Michael; Heuer, Holger; Smalla, Kornelia

    2016-05-01

    Naturally occurring drying-rewetting events in soil have been shown to affect the dissipation of veterinary antibiotics entering soil by manure fertilization. However, knowledge of effects on the soil microbial community structure and resistome is scarce. Here, consequences of drying-rewetting cycles on effects of sulfadiazine (SDZ) in soil planted with Dactylis glomerata L. were investigated in microcosms. Manure containing SDZ or not was applied to the pregrown grass and incubated for 56 days in a climate chamber. Water was either added daily or reduced during two drying events of 7 days, each followed by a recovery phase. Total community DNA was analyzed to reveal the effects on the bacterial community structure and on the abundance of sul1, sul2, intI1 ,intI2, qacE+qacEΔ1, traN and korB genes relative to 16S rRNA genes. 16S rRNA gene-based DGGE fingerprints indicated that drying-rewetting cycles modulated the effects of SDZ on the bacterial community structure in the soil. Furthermore, the SDZ treatment increased the relative abundance of sulfonamide resistance and integrase genes compared to the control. However, this increase was not different between moisture regimes, indicating that drying-rewetting had only a negligible effect on the selection of the resistome by SDZ in the manured soil. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. The emission of nitrous oxide upon wetting a rice soil following a dry season fallow

    Science.gov (United States)

    Byrnes, B. H.; Holt, L. S.; Austin, E. R.

    1993-12-01

    A greenhouse experiment was conducted to measure nitrous oxide (N2O) emissions from a soil, which had been planted to flooded transplanted rice, as it was rewetted to simulate the end of a dry season fallow period. The pots of soil had been cropped to transplanted rice with two commonly used nitrogen (N) fertilizer treatments and a control, and the soil had been puddled before transplanting. Large amounts of nitrate N accumulated in the soils during the dry season fallow, and the N fertilizers applied to the previous crop had little effect on nitrate accumulation. There was little N2O emission during the nitrification period. With water additions meant to simulate rainfall events at the beginning of a wet season, the soil redox dropped slightly, and large amounts of N2O began to be emitted. Large emissions began 5 days after each of the two simulated rainy season watering events and stopped abruptly at soil saturation, even though considerable amounts of nitrate still remained in the soil after saturation. Total measured emissions amounted to 6 to 7 kg N2O-N ha-1 for the period. Although these measurements were made in a system which may have favored nitrate accumulation, they are the first known measurements of N2O made from a rice soil as it is wetted. Nitrous oxide emitted from the flooding of rice soils that have accumulated nitrate during a dry season fallow may be a major source of N2O additions to the atmosphere.

  8. STATISTIC MODELING OF DRYING KINETHIC OF SPINACH LEAVES USING MICROWAVE AND HOT AIR METHODS

    Directory of Open Access Journals (Sweden)

    Mojtaba Nouri

    2015-06-01

    Full Text Available The target of this study was to model of spinach leaves drying using microwave and hot air dryer. This test performed in combination treatment of temperatures (50°C, 60°C, and 70°C and microwave (90, 180, 360, 600 and 900w in 3 replications. Sample moisture measured within drying. All the results were fitted and analyzed with 8 mathematical models base on 3 parameters including determination (R2, Chi square(X2, root mean square errors(RSME. Results also revealed that temperature and microwave power effectively reduce the drying time when increase. Drying occurs in degrading stage; moreover the comparison of results exhibited that Page and Two sentences models were fitted appropriately to estimate moisture changing and drying description. Regarding all the results, it is cleared that microwave method is an appropriate method in spinach drying as a result of reducing drying temperature and its high efficiency.

  9. Empirical Modeling on Hot Air Drying of Fresh and Pre-treated Pineapples

    Directory of Open Access Journals (Sweden)

    Tanongkankit Yardfon

    2016-01-01

    Full Text Available This research was aimed to study drying kinetics and determine empirical model of fresh pineapple and pre-treated pineapple with sucrose solution at different concentrations during drying. 3 mm thick samples were immersed into 30, 40 and 50 Brix of sucrose solution before hot air drying at temperatures of 60, 70 and 80°C. The empirical models to predict the drying kinetics were investigated. The results showed that the moisture content decreased when increasing the drying temperatures and times. Increase in sucrose concentration led to longer drying time. According to the statistical values of the highest coefficients (R2, the lowest least of chi-square (χ2 and root mean square error (RMSE, Logarithmic model was the best models for describing the drying behavior of soaked samples into 30, 40 and 50 Brix of sucrose solution.

  10. Organochlorine pesticides in soils of Mexico and the potential for soil-air exchange

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Fiona [Centre for Atmospheric Research Experiments, Science and Technology Branch, Environment Canada, 6248 Eighth Line, Egbert, Ontario L01 1N0 (Canada); Department of Chemistry, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4 (Canada); Alegria, Henry A. [Department of Environmental Science, Policy and Geography, University of South Florida St. Petersburg, 140 7th Ave. S., St. Petersburg, FL 33701 (United States); Bidleman, Terry F., E-mail: terry.bidleman@ec.gc.c [Centre for Atmospheric Research Experiments, Science and Technology Branch, Environment Canada, 6248 Eighth Line, Egbert, Ontario L01 1N0 (Canada)

    2010-03-15

    The spatial distribution of organochlorine pesticides (OCs) in soils and their potential for soil-air exchange was examined. The most prominent OCs were the DDTs (Geometric Mean, GM = 1.6 ng g{sup -1}), endosulfans (0.16 ng g{sup -1}), and toxaphenes (0.64 ng g{sup -1}). DDTs in soils of southern Mexico showed fresher signatures with higher F{sub DDTe} = p,p'-DDT/(p,p'-DDT + p,p'-DDE) and more racemic o,p'-DDT, while the signatures in the central and northern part of Mexico were more indicative of aged residues. Soil-air fugacity fractions showed that some soils are net recipients of DDTs from the atmosphere, while other soils are net sources. Toxaphene profiles in soils and air showed depletion of Parlar 39 and 42 which suggests that soil is the source to the atmosphere. Endosulfan was undergoing net deposition at most sites as it is a currently used pesticide. Other OCs showed wide variability in fugacity, suggesting a mix of net deposition and volatilization. - Chemical profiles of residues and soil-air fugacities are used to assess the potential of soil as a source of organochlorine pesticides to the air of Mexico.

  11. Organochlorine pesticides in soils of Mexico and the potential for soil-air exchange

    International Nuclear Information System (INIS)

    Wong, Fiona; Alegria, Henry A.; Bidleman, Terry F.

    2010-01-01

    The spatial distribution of organochlorine pesticides (OCs) in soils and their potential for soil-air exchange was examined. The most prominent OCs were the DDTs (Geometric Mean, GM = 1.6 ng g -1 ), endosulfans (0.16 ng g -1 ), and toxaphenes (0.64 ng g -1 ). DDTs in soils of southern Mexico showed fresher signatures with higher F DDTe = p,p'-DDT/(p,p'-DDT + p,p'-DDE) and more racemic o,p'-DDT, while the signatures in the central and northern part of Mexico were more indicative of aged residues. Soil-air fugacity fractions showed that some soils are net recipients of DDTs from the atmosphere, while other soils are net sources. Toxaphene profiles in soils and air showed depletion of Parlar 39 and 42 which suggests that soil is the source to the atmosphere. Endosulfan was undergoing net deposition at most sites as it is a currently used pesticide. Other OCs showed wide variability in fugacity, suggesting a mix of net deposition and volatilization. - Chemical profiles of residues and soil-air fugacities are used to assess the potential of soil as a source of organochlorine pesticides to the air of Mexico.

  12. Modelling pesticide volatilization after soil application using the mechanistic model Volt'Air

    Science.gov (United States)

    Bedos, Carole; Génermont, Sophie; Le Cadre, Edith; Garcia, Lucas; Barriuso, Enrique; Cellier, Pierre

    Volatilization of pesticides participates in atmospheric contamination and affects environmental ecosystems including human welfare. Modelling at relevant time and spatial scales is needed to better understand the complex processes involved in pesticide volatilization. Volt'Air-Pesticides has been developed following a two-step procedure to study pesticide volatilization at the field scale and at a quarter time step. Firstly, Volt'Air-NH 3 was adapted by extending the initial transfer of solutes to pesticides and by adding specific calculations for physico-chemical equilibriums as well as for the degradation of pesticides in soil. Secondly, the model was evaluated in terms of 3 pesticides applied on bare soil (atrazine, alachlor, and trifluralin) which display a wide range of volatilization rates. A sensitivity analysis confirmed the relevance of tuning to K h. Then, using Volt'Air-Pesticides, environmental conditions and emission fluxes of the pesticides were compared to fluxes measured under 2 environmental conditions. The model fairly well described water temporal dynamics, soil surface temperature, and energy budget. Overall, Volt'Air-Pesticides estimates of the order of magnitude of the volatilization flux of all three compounds were in good agreement with the field measurements. The model also satisfactorily simulated the decrease in the volatilization rate of the three pesticides during night-time as well as the decrease in the soil surface residue of trifluralin before and after incorporation. However, the timing of the maximum flux rate during the day was not correctly described, thought to be linked to an increased adsorption under dry soil conditions. Thanks to Volt'Air's capacity to deal with pedo-climatic conditions, several existing parameterizations describing adsorption as a function of soil water content could be tested. However, this point requires further investigation. Practically speaking, Volt'Air-Pesticides can be a useful tool to make

  13. Treatment of air dried archaeological wool textiles from waterlogged environment

    DEFF Research Database (Denmark)

    Scharff, Annemette Bruselius

    2014-01-01

    expanded the fibers and the yarn increased in size, resulting in more flexible and less brittle textiles. This property was kept when the textiles were dried by stepwise dehydration in ethanol, acetone, and white spirit with a final treatment in 5% lanolin. Preliminary tests on brittle textiles can...

  14. Phytopathology Prediction in Dry Soil Using Artificial Neural Networks Modeling

    OpenAIRE

    F. Allag; S. Bouharati; M. Belmahdi; R. Zegadi

    2014-01-01

    The rapid expansion of deserts in recent decades as a result of human actions combined with climatic changes has highlighted the necessity to understand biological processes in arid environments. Whereas physical processes and the biology of flora and fauna have been relatively well studied in marginally used arid areas, knowledge of desert soil micro-organisms remains fragmentary. The objective of this study is to conduct a diversity analysis of bacterial communities in unvegetated arid soil...

  15. Controls on surface soil drying rates observed by SMAP and simulated by the Noah land surface model

    Science.gov (United States)

    Shellito, Peter J.; Small, Eric E.; Livneh, Ben

    2018-03-01

    Drydown periods that follow precipitation events provide an opportunity to assess controls on soil evaporation on a continental scale. We use SMAP (Soil Moisture Active Passive) observations and Noah simulations from drydown periods to quantify the role of soil moisture, potential evaporation, vegetation cover, and soil texture on soil drying rates. Rates are determined using finite differences over intervals of 1 to 3 days. In the Noah model, the drying rates are a good approximation of direct soil evaporation rates, and our work suggests that SMAP-observed drying is also predominantly affected by direct soil evaporation. Data cover the domain of the North American Land Data Assimilation System Phase 2 and span the first 1.8 years of SMAP's operation. Drying of surface soil moisture observed by SMAP is faster than that simulated by Noah. SMAP drying is fastest when surface soil moisture levels are high, potential evaporation is high, and when vegetation cover is low. Soil texture plays a minor role in SMAP drying rates. Noah simulations show similar responses to soil moisture and potential evaporation, but vegetation has a minimal effect and soil texture has a much larger effect compared to SMAP. When drying rates are normalized by potential evaporation, SMAP observations and Noah simulations both show that increases in vegetation cover lead to decreases in evaporative efficiency from the surface soil. However, the magnitude of this effect simulated by Noah is much weaker than that determined from SMAP observations.

  16. Soil structure restoration by wet/dry cycles assessed by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Pires, L.F. [Univ. of Sao Paulo, Center for Nuclear Energy in Agriculture, Piracicaba, Sao Paulo (Brazil)

    2005-07-01

    Some studies have shown that soil structures can be restored through the sequence of wetting and drying cycles. These cycles causes changes in the soil pore system, which is very important to agriculture, because directly affect plant growth by root penetration, retention and movement of water and gases. The aim of this study was to follow by gamma-ray computed tomography (CT) the effect of soil wetting/drying process on the soil structure repairing of samples collected in cylinders. A first-generation tomograph with an {sup 241}Am source and a 7.62 x 7.62 cm NaI(Tl) scintillation crystal detector coupled to a photomultiplier tube was employed. Image analysis and tomographic unit profiles show that CT can provide an insight to sample structure restoration, which helps to have a better comprehension of soil physical hydraulic phenomena. (author)

  17. Soil structure restoration by wet/dry cycles assessed by computed tomography

    International Nuclear Information System (INIS)

    Pires, L.F.

    2005-01-01

    Some studies have shown that soil structures can be restored through the sequence of wetting and drying cycles. These cycles causes changes in the soil pore system, which is very important to agriculture, because directly affect plant growth by root penetration, retention and movement of water and gases. The aim of this study was to follow by gamma-ray computed tomography (CT) the effect of soil wetting/drying process on the soil structure repairing of samples collected in cylinders. A first-generation tomograph with an 241 Am source and a 7.62 x 7.62 cm NaI(Tl) scintillation crystal detector coupled to a photomultiplier tube was employed. Image analysis and tomographic unit profiles show that CT can provide an insight to sample structure restoration, which helps to have a better comprehension of soil physical hydraulic phenomena. (author)

  18. Resource Limitations on Soil Microbial Activity in an Antarctic Dry Valley

    DEFF Research Database (Denmark)

    Sparrow, Asley; Gregorich, Ed; Hopkins, David

    2011-01-01

    Although Antarctic dry valley soils function under some of the harshest environmental conditions on the planet, there is significant biological activity concentrated in small areas in the landscape. These productive areas serve as a source of C and N in organic matter redistributed...... to the surrounding biologically impoverished soils. We conducted a 3-yr replicated field experiment involving soil amendment with C and N in simple (glucose and NH4Cl) and complex (glycine and lacustrine detritus) forms to evaluate the resource limitations on soil microbial activity in an Antarctic dry valley....... The respiratory response for all substrates was slow, with a significant but weak response to NH4Cl, followed by a more widespread response to all substrates after 2 yr and in laboratory incubations conducted 3 yr after substrate addition. This response suggests that the soil microbial community is N limited and...

  19. Influence of forced air volume on water evaporation during sewage sludge bio-drying.

    Science.gov (United States)

    Cai, Lu; Chen, Tong-Bin; Gao, Ding; Zheng, Guo-Di; Liu, Hong-Tao; Pan, Tian-Hao

    2013-09-01

    Mechanical aeration is critical to sewage sludge bio-drying, and the actual water loss caused by aeration can be better understood from investigations of the relationship between aeration and water evaporation from the sewage sludge bio-drying pile based on in situ measurements. This study was conducted to investigate the effects of forced air volume on the evaporation of water from a sewage sludge bio-drying pile. Dewatered sewage sludge was bio-dried using control technology for bio-drying, during which time the temperature, superficial air velocity and water evaporation were measured and calculated. The results indicated that the peak air velocity and water evaporation occurred in the thermophilic phase and second temperature-increasing phase, with the highest values of 0.063 ± 0.027 m s(-1) and 28.9 kg ton(-1) matrix d(-1), respectively, being observed on day 4. Air velocity above the pile during aeration was 43-100% higher than when there was no aeration, and there was a significantly positive correlation between air volume and water evaporation from day 1 to 15. The order of daily means of water evaporation was thermophilic phase > second temperature-increasing phase > temperature-increasing phase > cooling phase. Forced aeration controlled the pile temperature and improved evaporation, making it the key factor influencing water loss during the process of sewage sludge bio-drying. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Dry-air drying at room temperature - a practical pre-treatment method of tree leaves for quantitative analyses of phenolics?

    Science.gov (United States)

    Tegelberg, Riitta; Virjamo, Virpi; Julkunen-Tiitto, Riitta

    2018-03-09

    In ecological experiments, storage of plant material is often needed between harvesting and laboratory analyses when the number of samples is too large for immediate, fresh analyses. Thus, accuracy and comparability of the results call for pre-treatment methods where the chemical composition remains unaltered and large number of samples can be treated efficiently. To study if a fast dry-air drying provides an efficient pre-treatment method for quantitative analyses of phenolics. Dry-air drying of mature leaves was done in a drying room equipped with dehumifier (10% relative humidity, room temperature) and results were compared to freeze-drying or freeze-drying after pre-freezing in liquid nitrogen. The quantities of methanol-soluble phenolics of Betula pendula Roth, Betula pubescens Ehrh., Salix myrsinifolia Salisb., Picea abies L. Karsten and Pinus sylvestris L. were analysed with HPLC and condensed tannins were analysed using the acid-butanol test. In deciduous tree leaves (Betula, Salix), the yield of most of the phenolic compounds was equal or higher in samples dried in dry-air room than the yield from freeze-dried samples. In Picea abies needles, however, dry-air drying caused severe reductions in picein, stilbenes, condensed tannin and (+)-catechin concentrations compared to freeze-drying. In Pinus sylvestris highest yields of neolignans but lowest yields of acetylated flavonoids were obtained from samples freeze-dried after pre-freezing. Results show that dry-air drying provides effective pre-treatment method for quantifying the soluble phenolics for deciduous tree leaves, but when analysing coniferous species, the different responses between structural classes of phenolics should be taken into account. Copyright © 2018 John Wiley & Sons, Ltd.

  1. The effect of osmotic pretreatment on the density of hot-air-dried carrot

    Directory of Open Access Journals (Sweden)

    J Soleimani

    2012-02-01

    Full Text Available Consumption of large amounts of fruits and vegetables throughout the world, have encouraged the development of various methods for their processing. Drying is considers as the most common method for preservation of vegetable and fruits. Although drying extend the shelf-life, it has various side effects on keeping quality of these foods; including decreasing of the color and texture quality as well as missing the flavor and nutritional values. These negative effects have increased the demand for the discovering the alternative drying methods and consequently for the production of fresh-like products. The aim of this study was to introduce and optimize the novel method for the drying of carrot as well as to develop and optimize the quality of osmo-air-dried carrots with special respect to the color, flavor, texture, rehydration properties, density and shriveling of the product. For this, the effect of osmotic pretreatment on the density of carrot slices was investigated, using 50% glucose syrup +5% salt at 40°C with 150 rpm, followed by complementary drying step. The result of treated group was compared with control samples which were dried only by hot-air-drier. The results showed that using osmotic pretreatment could increase the density through inhibition of the product's shrinkage. Meanwhile, in air-dried samples the density was decreased considerably and high shrinkage was also observed.

  2. Effect of hot-air drying on the physicochemical properties of kaffir lime leaves (Citrus hystrix)

    OpenAIRE

    Juhari, Nurul Hanisah Binti; Lasekan, Ola; Muhammad, Kharidah; Karim, Shahrim

    2013-01-01

    The effect of hot-air drying namely drying time (3-15 h), drying temperature (40-80°C) and loading capacity (0.5-2.0 kg/m2 ) on the physicochemical characteristics of kaffir lime leaves was optimized using Response Surface Methodology. Twenty treatments were assigned based on the second- order CCD including 6 center points, 6 axial points and 8 factorial points. The quality of dried kaffir lime leaves was evaluated by determining moisture content, water activity, texture (brittleness) and Hun...

  3. Processes affecting the movement of organochlorine pesticides (OCPs) between soil and air in an industrial site in Turkey.

    Science.gov (United States)

    Bozlaker, Ayse; Muezzinoglu, Aysen; Odabasi, Mustafa

    2009-11-01

    Soil and atmospheric concentrations, dry deposition and soil-air gas exchange of organochlorine pesticides (OCPs) were investigated at an industrial site in Aliaga, Izmir, Turkey. Current-use pesticides, endosulfan and chlorpyrifos, had the highest atmospheric levels in summer and winter. Summertime total (gas+particle) OCP concentrations in air were higher, probably due to increased volatilization at higher temperatures and seasonal local/regional applications of current-use pesticides. Particle deposition fluxes were generally higher in summer than in winter. Overall average dry particle deposition velocity for all the OCPs was 4.9+/-4.1 cm s(-1) (average+/-SD). SigmaDDXs (sum of p,p'-DDT, p,p'-DDD, and p,p'-DDE) were the most abundant OCPs in Aliaga soils (n=48), probably due to their heavy historical use and persistence. Calculated fugacity ratios and average net gas fluxes across the soil-air interface indicated volatilization for alpha-CHL, gamma-CHL, heptachlorepoxide, cis-nonachlor, trans-nonachlor, and p,p'-DDT in summer, and for alpha-CHL, gamma-CHL, trans-nonachlor, endosulfan sulfate, and p,p'-DDT in winter. For the remaining OCPs, soil acted as a sink during both seasons. Comparison of the determined fluxes showed that dry particle, gas-phase, and wet deposition are significant OCP input mechanisms to the soil in the study area.

  4. Mathematical modeling of hot air/electrohydrodynamic (EHD) drying kinetics of mushroom slices

    International Nuclear Information System (INIS)

    Taghian Dinani, Somayeh; Hamdami, Nasser; Shahedi, Mohammad; Havet, Michel

    2014-01-01

    Highlights: • Hot air/EHD drying behavior of thin layer mushroom slices was evaluated. • A new empirical model was proposed for drying kinetics modeling of mushroom slices. • The new model presents excellent predictions for hot air/EHD drying of mushroom. - Abstract: Researches about mathematical modeling of electrohydrodynamic (EHD) drying are rare. In this study, hot air combined with electrohydrodynamic (EHD) drying behavior of thin layer mushroom slices was evaluated in a laboratory scale dryer at voltages of 17, 19, and 21 kV and electrode gaps of 5, 6, and 7 cm. The drying curves were fitted to ten different mathematical models (Newton, Page, Modified Page, Henderson and Pabis, Logarithmic, Two-term exponential, Midilli and Kucuk, Wang and Singh, Weibull and Parabolic models) and a proposed new empirical model to select a suitable drying equation for drying mushroom slices in a hot air combined with EHD dryer. Coefficients of the models were determined by non-linear regression analysis and the models were compared based on their coefficient of determination (R 2 ), sum of square errors (SSE) and root mean square error (RMSE) between experimental and predicted moisture ratios. According to the results, the proposed model that contains only three parameters provided the best fit with the experimental data. It was closely followed by the Midilli and Kucuk model that contains four parameters. Therefore, the proposed model can present comfortable usage and excellent predictions for the moisture content changes of mushroom slices in the hot air combined with EHD drying system

  5. Quantitative assessment of pedodiversity and soil erosion within a karst sinkhole in the dry steppe subzone

    Science.gov (United States)

    Smirnova, M. A.; Gennadiev, A. N.

    2017-08-01

    A detailed study of the soil cover of a sinkhole (300 m2) in the dry steppe landscape of the Bogdinsk-Baskunchak Natural Reserve in Astrakhan oblast has been performed, and the factors of its differentiation have been analyzed. The indices of pedodiversity have been calculated and compared for karst sinkholes in the dry steppe and northern taiga landscapes. Quantitative parameters of the lateral migration of solid soil substances on the slopes of the sinkhole have been determined. The rate of soil erosion decreases from the slope of southern aspect to the slopes of western, northern, and eastern aspects. On the average, it is estimated at 0.4 mm/yr. The average rate of accumulation of solid substances on the lower parts of the slopes and in the bottom of the sinkhole reaches 0.74 mm/yr. A comparative analysis of the soil properties attests to their dependence on the particular position of a given soil within the sinkhole. Downward the slopes of the sinkhole, full-profile brown arid soils (Cambic Calcisols) are replaced by sierozem-like soils (Haplic Calcisols), light-humus poorly developed soils (Luvisols), lithozems (Leptosols), and stratified soils (stratozems, or Colluvic Regosols). The soils within the upper ring-shape soil microzone are more diverse and contrasting with respect to their morphological, physical, chemical, and physicochemical properties. The degree of soil contrasts decreases down the slopes of the sinkhole towards its bottom. The studied sinkhole is characterized by considerable pedodiversity. Quantitative parameters of pedodiversity for the sinkhole in the dry steppe zone are higher than those form the sinkholes in the northern taiga zone.

  6. Changes in duration of dry and wet spells associated with air temperatures in Russia

    Science.gov (United States)

    Ye, Hengchun

    2018-03-01

    This study uses daily precipitation records from 517 Russian stations (1966-2010) to examine the relationships between continuous dry and wet day duration and surface air temperature for all four seasons. The study found that both mean and extreme durations of dry periods increase with air temperature at about 7.0% (0.24 day/°C) and 7.7% (0.86 day/°C) respectively, while those of wet periods decrease at about 1.3% (-0.02 day/°C) and 2.2% (-0.10 day/°C) respectively averaged over the entire study region during summer. An increase in the duration of dry periods with higher air temperature is also found in other seasons at locations with a mean seasonal air temperature of about -5 °C or higher. Opposite relationships of shorter durations of dry periods and longer wet periods associated with higher air temperature are observed over the northern part of the study region in winter. The changes in durations of both dry and wet periods have significant correlations with the changes in total dry and wet days but are about 2.5 times higher for dry periods and 0.5 times lower for wet periods. The study also found that locations with longer durations of dry periods experience faster rates of increase in air temperature, suggesting the likelihood of exacerbating drought severity in drier and/or warmer locations for all seasons.

  7. Hyperventilation with cold versus dry air in 2- to 5-year-old children with asthma

    DEFF Research Database (Denmark)

    Nielsen, Kim G; Bisgaard, Hans

    2005-01-01

    UNLABELLED: Cold air challenge (CACh) has been shown to discriminate between children with asthma and healthy young children. Hyperventilation with dry room-temperature air is a simplified alternative. We compared responsiveness in young children with asthma between two standardized, single......-subject SDs (SDw). The challenge sequence was randomly assigned. A comparator challenge was performed 1 hour later if the first challenge gave a change of 3 SDw or more. Forty 2- to 5-year-old children with asthma were included. Responsiveness to cold versus dry air showed significant, but weak, correlation...

  8. Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

    Science.gov (United States)

    Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

    2013-10-01

    The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency. © 2013 John Wiley & Sons Ltd.

  9. Soil water storage, rainfall and runoff relationships in a tropical dry forest catchment

    Science.gov (United States)

    Farrick, Kegan K.; Branfireun, Brian A.

    2014-12-01

    In forested catchments, the exceedance of rainfall and antecedent water storage thresholds is often required for runoff generation, yet to our knowledge these threshold relationships remain undescribed in tropical dry forest catchments. We, therefore, identified the controls of streamflow activation and the timing and magnitude of runoff in a tropical dry forest catchment near the Pacific coast of central Mexico. During a 52 day transition phase from the dry to wet season, soil water movement was dominated by vertical flow which continued until a threshold soil moisture content of 26% was reached at 100 cm below the surface. This satisfied a 162 mm storage deficit and activated streamflow, likely through lateral subsurface flow pathways. High antecedent soil water conditions were maintained during the wet phase but had a weak influence on stormflow. We identified a threshold value of 289 mm of summed rainfall and antecedent soil water needed to generate >4 mm of stormflow per event. Above this threshold, stormflow response and magnitude was almost entirely governed by rainfall event characteristics and not antecedent soil moisture conditions. Our results show that over the course of the wet season in tropical dry forests the dominant controls on runoff generation changed from antecedent soil water and storage to the depth of rainfall.

  10. Copper pollution decreases the resistance of soil microbial community to subsequent dry-rewetting disturbance.

    Science.gov (United States)

    Li, Jing; Wang, Jun-Tao; Hu, Hang-Wei; Ma, Yi-Bing; Zhang, Li-Mei; He, Ji-Zheng

    2016-01-01

    Dry-rewetting (DW) disturbance frequently occurs in soils due to rainfall and irrigation, and the frequency of DW cycles might exert significant influences on soil microbial communities and their mediated functions. However, how microorganisms respond to DW alternations in soils with a history of heavy metal pollution remains largely unknown. Here, soil laboratory microcosms were constructed to explore the impacts of ten DW cycles on the soil microbial communities in two contrasting soils (fluvo-aquic soil and red soil) under three copper concentrations (zero, medium and high). Results showed that the fluctuations of substrate induced respiration (SIR) decreased with repeated cycles of DW alternation. Furthermore, the resistance values of substrate induced respiration (RS-SIR) were highest in non-copper-stressed (zero) soils. Structural equation model (SEM) analysis ascertained that the shifts of bacterial communities determined the changes of RS-SIR in both soils. The rate of bacterial community variance was significantly lower in non-copper-stressed soil compared to the other two copper-stressed (medium and high) soils, which might lead to the higher RS-SIR in the fluvo-aquic soil. As for the red soil, the substantial increase of the dominant group WPS-2 after DW disturbance might result in the low RS-SIR in the high copper-stressed soil. Moreover, in both soils, the bacterial diversity was highest in non-copper-stressed soils. Our results revealed that initial copper stress could decrease the resistance of soil microbial community structure and function to subsequent DW disturbance. Copyright © 2015. Published by Elsevier B.V.

  11. Drying/rewetting cycles mobilize old C from deep soils from a California annual grassland

    OpenAIRE

    Schimel, JP; Wetterstedt, JAM; Holden, PA; Trumbore, SE

    2011-01-01

    We measured the 14 C and 13 C signatures of CO 2 respired from surface and deep soils released through multiple dry/rewetting cycles in laboratory incubations. The C respired from surface soils included components fixed before and after the 1960s. However, that respired from deep soils was derived from organic matter with a mean turnover time estimated in the range of 650-850 years. This reinforces previous research suggesting that a substantial amount of deep soil C is chemically labile b...

  12. Air pollution dry deposition: radioisotopes as particles and volatiles

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This study focuses on determining volcanic ash and ambient airborne solids concentrations at various sampling sites subsequent to the Mt. St. Helens' eruption in order to develop an experimental basis for models predicting removal of airborne particles and gases by dry deposition onto outdoor surfaces. In addition, deposition rates were determined using dual tracer techniques in the field and in a wind tunnel in the laboratory

  13. Dry storage systems with free convection air cooling

    International Nuclear Information System (INIS)

    Kioes, S.R.

    1980-01-01

    Several design principles to remove heat from the spent fuel by free air convection are illustrated and described. The key safety considerations were felt to be: loss of coolant is impossible as the passive system uses air as a coolant; overheating is precluded because as the temperatures of the containers rises the coolant flow rate increases; mass of the storage building provides a large heat sink and therefore a rapid temperature rise is impossible; and lack of any active external support requirements makes the cooling process less likely to equipment or operator failures. An example of this type of storage already exists. The German HTGR is operated with spherical graphite fuel elements which are stored in canister and in storage cells. The concept is a double cooling system with free convection inside the cells and heat exchange via two side walls of the cell to the ambient air in the cooling ducts. Technical description of the TN 1300 cask is also presented

  14. Can differences in root responses to soil drying and compaction explain differences in performance of trees growing on landfill sites?

    Science.gov (United States)

    Liang, Jiansheng; Zhang, Jianhua; Chan, Gilbert Y. S.; Wong, M. H.

    1999-07-01

    Two tropical woody species, Acacia confusa Merrill and Litsea glutinosa (Lour.) C.B. Robinson, were grown under controlled conditions in PVC pipes filled with John Innes No. 2 soil. To investigate root distribution, physiological characteristics and hydraulic conductivity, four soil treatments were imposed-well-watered and noncompacted (control), well-watered and compacted; unwatered and noncompacted, and unwatered and compacted. In L. glutinosa, rooting depth and root elongation were severely restricted when soil bulk density increased from around 1.12 to 1.62 g cm(-3), whereas soil compaction had little effect on these parameters in A. confusa. As soil drying progressed, root water potential and osmotic potential declined more slowly in L. glutinosa than in A. confusa. Both the soil drying and compaction treatments significantly stimulated the accumulation of root abscisic acid (ABA) in both species. Soil drying damaged the root cell membrane of A. confusa, but had little influence on the root cell membrane of L. glutinosa. Soil drying had a greater effect on root hydraulic conductivity (L(p)) in L. glutinosa than in A. confusa, whereas the effect of soil compaction on L(p) was less in L. glutinosa than in A. confusa. Soil drying enhanced the effects of soil compaction on root L(p). We conclude that soil drying and compaction have large species-specific effects on the distribution, growth and physiology of roots. The relationships of these root properties to the species' ability to tolerate unfavorable soil conditions were examined.

  15. Role of wetting and drying cycles in formation and growth of soil aggregates

    Science.gov (United States)

    Ghezzehei, T. A.; Lopez, J. P.

    2009-12-01

    Soil structure directly determines important soil physical properties including porosity, hydraulic conductivity, water retention, and mechanical strength and indirectly influences most biological and chemical processes that occur in and around soil. In response to the various processes that occur within it, soil structure evolves continuously at multiple spatial and temporal scales. We hypothesize that the rhythm of the evolution is controlled by wetting and drying cycles. Here, we will present a mathematical description of the role of wetting and drying cycles in the formation and stabilization of soil aggregates with emphasis on two important roles of wetting and drying cycles: (1) transport and deposition of organic and inorganic cementing agents at the most effective locations, (2) chemical and physical alteration of cementing agents during desiccation and the resultant semi-permanent bonding (or bond hardening). Our results demonstrate that size and strength of aggregates are determined by particle size, degree of dryness, number of wetting-drying cycles, as well as concentration and solubility of dissolved and/or colloidal cementing agents. These results are in general agreement with experimental observations obtained from the literature.

  16. Performance Recovery of Natural Draft Dry Cooling Systems by Combined Air Leading Strategies

    Directory of Open Access Journals (Sweden)

    Weijia Wang

    2017-12-01

    Full Text Available The cooling efficiency of natural draft dry cooling system (NDDCS are vulnerable to ambient winds, so the implementation of measures against the wind effects is of great importance. This work presents the combined air leading strategies to recover the flow and heat transfer performances of NDDCS. Following the energy balance among the exhaust steam, circulating water, and cooling air, numerical models of natural draft dry cooling systems with the combined air leading strategies are developed. The cooling air streamlines, volume effectiveness, thermal efficiency and outlet water temperature for each cooling delta of the large-scale heat exchanger are obtained. The overall volume effectiveness, average outlet water temperature of NDDCS and steam turbine back pressure are calculated. The results show that with the air leading strategies inside or outside the dry-cooling tower, the thermo-flow performances of natural draft dry cooling system are improved under all wind conditions. The combined inner and outer air leading strategies are superior to other single strategy in the performance recovery, thus can be recommended for NDDCS in power generating units.

  17. Research on the Effects of Drying Temperature on Nitrogen Detection of Different Soil Types by Near Infrared Sensors.

    Science.gov (United States)

    Nie, Pengcheng; Dong, Tao; He, Yong; Xiao, Shupei

    2018-01-29

    Soil is a complicated system whose components and mechanisms are complex and difficult to be fully excavated and comprehended. Nitrogen is the key parameter supporting plant growth and development, and is the material basis of plant growth as well. An accurate grasp of soil nitrogen information is the premise of scientific fertilization in precision agriculture, where near infrared sensors are widely used for rapid detection of nutrients in soil. However, soil texture, soil moisture content and drying temperature all affect soil nitrogen detection using near infrared sensors. In order to investigate the effects of drying temperature on the nitrogen detection in black soil, loess and calcium soil, three kinds of soils were detected by near infrared sensors after 25 °C placement (ambient temperature), 50 °C drying (medium temperature), 80 °C drying (medium-high temperature) and 95 °C drying (high temperature). The successive projections algorithm based on multiple linear regression (SPA-MLR), partial least squares (PLS) and competitive adaptive reweighted squares (CARS) were used to model and analyze the spectral information of different soil types. The predictive abilities were assessed using the prediction correlation coefficients (R P ), the root mean squared error of prediction (RMSEP), and the residual predictive deviation (RPD). The results showed that the loess (R P = 0.9721, RMSEP = 0.067 g/kg, RPD = 4.34) and calcium soil (R P = 0.9588, RMSEP = 0.094 g/kg, RPD = 3.89) obtained the best prediction accuracy after 95 °C drying. The detection results of black soil (R P = 0.9486, RMSEP = 0.22 g/kg, RPD = 2.82) after 80 °C drying were the optimum. In conclusion, drying temperature does have an obvious influence on the detection of soil nitrogen by near infrared sensors, and the suitable drying temperature for different soil types was of great significance in enhancing the detection accuracy.

  18. Improving Malaysian cocoa quality through the use of dehumidified air under mild drying conditions.

    Science.gov (United States)

    Hii, Ching L; Law, Chung L; Cloke, Michael; Sharif, Suzannah

    2011-01-30

    Various studies have been conducted in the past to improve the quality of Malaysian cocoa beans. However, the processing methods still remain crude and lack technological advancement. In terms of drying, no previous study has attempted to apply advanced drying technology to improve bean quality. This paper presents the first attempt to improve the quality of cocoa beans through heat pump drying using constant air (28.6 and 40.4 °C) and stepwise (step-up 30.7-43.6-56.9 °C and step-down 54.9-43.9 °C) drying profiles. Comparison was made against hot air drying at 55.9 °C. Product quality assessment showed significant improvement in the quality of Malaysian cocoa beans. Quality was found to be better in terms of lower acidity (higher pH) and higher degree of browning (cut test) for cocoa beans dried using the step-up profile. All heat pump-dried samples showed flavour quality comparable to that of Ghanaian and better than that of Malaysian and Indonesian commercial samples. Step-up-dried samples showed the best flavour profile with high level of cocoa flavour, low in sourness and not excessive in bitterness and astringency. Dried cocoa samples from the step-up drying profile showed the best overall quality as compared with commercial samples from Malaysia, Indonesia and Ghana. The improvement of Malaysian cocoa bean quality is thus achievable through heat pump drying. 2010 Society of Chemical Industry.

  19. Particle dry-deposition experiment using ambient airborne soil

    International Nuclear Information System (INIS)

    Sehmel, G.A.

    1979-01-01

    Airborne solid concentrations were measured simultaneously at sampling towers upwind and 305-m downwind of a site. When the wind speed and wind direction were identical at each site, isokinetic air samplers on the sampling towers were automatically activated. The fraction of the airborne solid plume remaining after the 305-m fetch ranged from 0.53 to 1.07

  20. Control of aromatic-waste air streams by soil bioreactors

    International Nuclear Information System (INIS)

    Miller, D.E.; Canter, L.W.

    1991-01-01

    Contamination of groundwater resources is a serious environmental problem which is continuing to increase in occurrence in the United States. It has been reported that leaking underground gasoline storage tanks may pose the most serious threat of all sources of groundwater contamination. Gasolines are comprised of a variety of aliphatic and aromatic hydrocarbons. The aromatic portion consists primarily of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). BTEX compounds are also among the most frequency identified substances at Superfund sites. Pump and treat well systems are the most common and frequently used technique for aquifer restoration. Treatment is often in the form of air stripping to remove the volatile components from the contaminated water. Additionally, soil ventilation processes have been used to remove volatile components from the vadose zone. Both air stripping and soil ventilation produce a waste gas stream containing volatile compounds which is normally treated by carbon adsorption or incineration. Both treatment processes require a substantial capital investment and continual operation and maintenance expenditures. The objective of the study was to examine the potential of using soil bioreactors to treat a waste gas stream produced by air stripping or soil ventilation process. Previous studies have shown that various hydrocarbons can be successfully treated with soils. The study examined the removal of BTEX compounds within soil columns and the influence of soil type, inlet concentration, and inlet flow rate on the removal efficiency

  1. The Effect of Temperature and Air Velocity on Drying Kinetics of Pistachio Nuts during Roasting by using Hot Air Flow

    Directory of Open Access Journals (Sweden)

    A Dini

    2017-10-01

    Full Text Available Introduction Pistachio nut is one of the most delicious and nutritious nuts in the world and it is being used as a saltedand roasted product or as an ingredient in snacks, ice cream, desserts, etc. The purpose of roasting is to promote flavour and texture changes in nuts that ultimately increase the overall palatability of the product.Roasting involves a number of physico-chemical changes, including heat exchange, chemical reactions and drying. Knowledge of desorption kinetics is essential to predict the behavior of the material during roasting process and to design roaster equipment.The main aim of this research was to evaluate suitable models for predicting moisture ratio, the effect of air temperature and velocity on the drying kinetics of pistachio nuts and obtain the effective diffusivity coefficient and activation energy in the drying process during the roasting of pistachio nuts. Materials and Methods Dried Ahmadaghaei pistachio nuts were supplied from Kashefan Kavir company (Doraj co. in Rafsanjan. Pistachio nuts were soaked in 17% salt solution for 8 minute and roasting was investigated at air temperatures of 120,130, 145, 160 and 170 °C and air velocities of 0.6, 0.88, 1.3, 1.72 and 2 ms-1. Five semi-theoretical and two empirical kinetic models were fitted to drying experimental data using nonlinear regression analysis techniques in the Curve Expert 2.2 computer program. Results and Discussion Tow-way ANOVA indicated that temperature and hot air velocity significantly affected the drying process during roasting of shelled pistachio nuts. The higher roasting temperatures and air velocities resulted in the higher drying rates. During first 10 min of roasting at constant air velocity of 1.3 ms-1, 64.5%, 70.3%, 77.1%, 83.5%, 89.7% of the moisture were removed at roasting air temperatures of 120 °C, 130 °C, 145 °C, 160 °C, 170 °C, respectively. The high regression coefficients (R2>0.996 and low reduced chi-square (χ2, mean relative

  2. Soil sample moisture content as a function of time during oven drying for gamma-ray spectroscopic measurements

    International Nuclear Information System (INIS)

    Benke, R.R.; Kearfott, K.J.

    1999-01-01

    In routine gamma-ray spectroscopic analysis of collected soil samples, procedure often calls to remove soil moisture by oven drying overnight at a temperature of 100 deg. C . Oven drying not only minimizes the gamma-ray self-attenuation of soil samples due to the absence of water during the gamma-ray spectroscopic analysis, but also allows for a straightforward calculation of the specific activity of radionuclides in soil, historically based on the sample dry weight. Because radon exhalation is strongly dependent on moisture , knowledge of the oven-drying time dependence of the soil moisture content, combined with radon exhalation measurements during oven drying and at room temperature for varying soil moisture contents, would allow conclusions to be made on how the oven-drying radon exhalation rate depends on soil moisture content. Determinations of the oven-drying radon exhalation from soil samples allow corrections to be made for the immediate laboratory gamma-ray spectroscopy of radionuclides in the natural uranium decay chain. This paper presents the results of soil moisture content measurements during oven drying and suggests useful empirical fits to the moisture data

  3. Nitrogen mineralization from anaerobically digested centrifuge cake and aged air-dried biosolids.

    Science.gov (United States)

    Kumar, Kuldip; Hundal, Lakhwinder S; Cox, Albert E; Granato, Thomas

    2014-09-01

    This study was conducted to estimate nitrogen (N) mineralization of anaerobically digested centrifuge cake from the Stickney Water Reclamation Plant (SWRP) and Calumet Water Reclamation Plant (CWRP), lagoon-aged air-dried biosolids from the CWRP, and Milorganite at three rates of application (0, 12.5 and 25 Mg ha(-1)). The N mineralized varied among biosolids as follows: Milorganite (44%) > SWRP centrifuge cake (35%) > CWRP centrifuge cake (31%) > aged air-dried (13%). The N mineralized in the SWRP cake (32%) and CWRP aged air-dried biosolids (12%) determined from the 15N study were in agreement with the first study. The N mineralization value for centrifuge cake biosolids observed in our study is higher than the value given in the Part 503 rule and Illinois Part 391 guidelines. These results will be used to fine-tune biosolids application rate to match crop N demand without compromising yield while minimizing any adverse effect on the environment.

  4. Solar air heaters for industrial drying; Aquecedor solar de ar para secagem industrial

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Everaldo Mendes [Governo do Estado da Paraiba, Joao Pessoa, PB (Brazil). Secretaria de Planejamento e Gestao

    2008-07-01

    The objective of this study is to encourage the use of solar energy in industrial drying of fruits, with the producers poles, at the same time, promote the rational use of energy for heat, or replacing the hydroelectric and oil derivatives for this purpose. This study is presented in the following chapters: availability of solar energy; details of constructive solar heated air; drying fruit; market. (author)

  5. The volatile oil composition of fresh and air-dried buds of Cannabis sativa.

    Science.gov (United States)

    Ross, S A; ElSohly, M A

    1996-01-01

    The composition of the steam-distilled volatile oil of fresh and air-dried, indoor-grown marijuana was studied by GC/FID and GC/MS. In all, 68 components were detected of which 57 were fully identified. Drying of the plant material had no effect on the qualitative composition of the oil and did not affect the ability of individuals familiar with marijuana smell to recognize the odor.

  6. Air encapsulation. I. Measurement in a field soil

    International Nuclear Information System (INIS)

    Fayer, M.J.; Hillel, D.

    1986-01-01

    Encapsulated air is an important component of shallow water table fluctuations. Their objective was to measure the quantity and persistence of encapsulated air in a field setting. Using sprinkling rates of either 3.5 x 10 -6 or 3.8 x 10 -5 m s -1 , they brought the water table in a field soil from a depth of 1.5 m to the surface on several occasions. Moisture contents during and after sprinkling were monitored with a neutron probe. Twice following sprinkling, the water table was maintained at the surface for more than 20 d, during which time they continued to monitor moisture contents. With the water table at the surface, differences between the porosity and the measured moisture content were attributed to encapsulated air. Encapsulated air contents ranged from 1.1 to 6.3% of the bulk soil volume, depending on the rate of sprinkling, soil depth, and initial soil moisture content. During ponding, encapsulated air persisted at the 0.3-m depth for up to 28 d. The results indicate that encapsulated air is measurable in a field situation and that its quantity and persistence should be considered in analyzing the results of similar field experiments. 16 references

  7. Organochlorine pesticides in soils and air of southern Mexico: Chemical profiles and potential for soil emissions

    Science.gov (United States)

    Wong, Fiona; Alegria, Henry A.; Jantunen, Liisa M.; Bidleman, Terry F.; Salvador-Figueroa, Miguel; Gold-Bouchot, Gerardo; Ceja-Moreno, Victor; Waliszewski, Stefan M.; Infanzon, Raul

    The extent of organochlorine pesticides (OCs) contamination in southern Mexico was investigated in this study. Biweekly air samplings were carried out in two sites in the state of Chiapas (during 2002-2003), and one in each state of Veracruz and Tabasco (during 2003-2004). Corresponding to the air sampling locations, soil samples were also collected to gauge the soil-air exchange of OCs in the region. ∑DDTs in soils ranged from 0.057 to 360 ng g -1 whereas those in air ranged from 240 to 2400 pg m -3. DDT and metabolite DDE were expressed as fractional values, FDDTe = p, p'-DDT/( p, p'-DDT + p, p'-DDE) and FDDTo = p,p'-DDT/( p,p'-DDT + o,p'-DDT). FDDTe in soils ranged from 0.30 to 0.69 while those in air ranged from 0.45 to 0.84. FDDTe in air at a farm in Chiapas (0.84) was closer to that of technical DDT (0.95) which is suggestive of fresh DDT input. Enantiomer fractions (EF) of o,p'-DDT in air were racemic at all locations (0.500-0.504). However, nonracemic o,p'-DDT was seen in the soils (EFs = 0.456-0.647). Fugacities of OCs in soil ( fs) and air ( fa) were calculated, and the fugacity fraction, ff = fs/( fs + fa) of DDTs ranged from 0.013 to 0.97 which indicated a mix of net deposition ( ff 0.5) from soil among the sites. It is suggested that DDTs in Mexico air are due to a combination of ongoing regional usage and re-emission of old DDT residues from soils. Total toxaphene in soils ranged from 0.066 to 69 ng g -1 while levels in air ranged from 6.2 to 230 pg m -3. Chromatographic profiles of toxaphenes in both air and soil showed depletion of Parlar congeners 39 and 42. Fugacity fractions of toxaphene were within the equilibrium range or above the upper equilibrium threshold boundary. These findings suggested that soil emission of old residues is the main source of toxaphenes to the atmosphere. Results from this study provide baseline data for establishing a long-term OC monitoring program in Mexico.

  8. Green ambrosia for Soil- Dry Cow Dung Powder: Rhexistasy to Biostasy

    Science.gov (United States)

    Bagla, Hemlata; Barot, Nisha

    2013-04-01

    "Greener ambrosia for Soil - Dry cow dung powder: Rhexistasy to Biostasy" Pedosphere, the soil with its biotic and abiotic component, is produced by lithosphere`s interactions with atmosphere, hydrosphere and biosphere. The theory of Biorhexistasy proposed by pedologist H. Erhart [1], describes two crucial climatic phases of soil i.e. Biostasy, period of soil formation and Rhexistasy, periods of soil erosion. Humus, the organic matter in soil, permits better aeration, enhances the absorption and releases nutrients, and makes the soil less susceptible to leaching and erosion [2], thus the agent of soil`s vitality. Mismanagement of soil, leads to the degradation of millions of acres of land through erosion, compaction, salinization and acidification. Among these threats salinity is a major abiotic stress reducing the yield of wide variety of crops all over the world [3]. It is been proved that Humic Acid (HA) treatment can ameliorate the deleterious effects of salt stress by increasing root growth, altering mineral uptake, and decreasing membrane damage, thus inducing salt tolerance in plants [4]. HA can be inexpensively incorporated into soils via different biowastes. Dry cow dung powder (DCP), is naturally available bio-organic, complex, polymorphic humified fecal matter, enriched with minerals, carbohydrates, fats, proteins, bile pigments, aliphatic - aromatic species such as HA, Fulvic Acid (FA) etc [5]. The microbial consortium enables DCP with considerable potentials for biodegradation and biotransformation of even saline soil and further contributes to many biogeochemical processes, boosting humus content of soil. Due to unambiguous biological, microbiological as well as chemical inert properties of DCP, it has been successfully utilized as a fertilizer and soil conditioner since ages in India, one of the leading agrarian countries of the world. Thus we summarize that DCP is one of the best contenders for the biostasy and desaliner of soil, aptly, soil`s

  9. Forced Hot Air to Dry Feces and Kill Bacteria on Transport Cage Flooring

    Science.gov (United States)

    Due to fecal shedding from positive birds, broiler transport cages can be contaminated with human bacterial pathogens leading to cross contamination of previously negative broilers during live haul. Earlier work has shown that drying soiled or washed cages for 24 to 48 hours can lower or even elimi...

  10. Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees

    Science.gov (United States)

    Pamela E. Padgett; Hillary Cook; Andrzej Bytnerowicz; Robert L. Heath

    2009-01-01

    Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to...

  11. Effect of additives and steaming on quality of air dried noodles

    OpenAIRE

    Gatade, Abhijeet Arun; Sahoo, Akshaya Kumar

    2015-01-01

    Texture is the most important property for consumer acceptance in cooked noodles. The air dried noodles are known to have higher cooking loss and cooking time, to that of instant fried noodles. But the fat content of instant fried noodles is more. In the present work attempts were made to optimize the moisture content so as to obtain a smooth dough for extruded noodle preparation and develop air dried noodles of low fat content with lesser cooking loss and cooking time. To meet the objectives...

  12. Robust Vacuum-/Air-Dried Graphene Aerogels and Fast Recoverable Shape-Memory Hybrid Foams.

    Science.gov (United States)

    Li, Chenwei; Qiu, Ling; Zhang, Baoqing; Li, Dan; Liu, Chen-Yang

    2016-02-17

    New graphene aerogels can be fabricated by vacuum/air drying, and because of the mechanical robustness of the graphene aerogels, shape-memory polymer/graphene hybrid foams can be fabricated by a simple infiltration-air-drying-crosslinking method. Due to the superelasticity, high strength, and good electrical conductivity of the as-prepared graphene aerogels, the shape-memory hybrid foams exhibit excellent thermotropical and electrical shape-memory properties, outperforming previously reported shape-memory polymer foams. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Linear GPR inversion for lossy soil and a planar air-soil interface

    DEFF Research Database (Denmark)

    Meincke, Peter

    2001-01-01

    A three-dimensional inversion scheme for fixed-offset ground penetrating radar (GPR) is derived that takes into account the loss in the soil and the planar air-soil interface. The forward model of this inversion scheme is based upon the first Born approximation and the dyadic Green function...

  14. Contrasted response of colloidal, organic and inorganic dissolved phosphorus forms during rewetting of dried riparian soils

    Science.gov (United States)

    Gu, Sen; Gruau, Gérard; Malique, François; Dupas, Rémi; Gascuel-Odoux, Chantal; Petitjean, Patrice; Bouhnik-Le Coz, Martine

    2017-04-01

    Riparian vegetated buffer strip (RVBS) are currently used to protect surface waters from phosphorus (P) emissions because of their ability to retain P-enriched soil particles. However, this protection role may be counterbalanced by the development in these zones of conditions able to trigger the release of highly mobile dissolved or colloidal P forms. Rewetting after drying is one of these conditions. So far, the potential sources of P mobilized during rewetting after drying are not clearly identified, nor are clearly identified the chemical nature of the released dissolved P species, or the role of the soil P speciation on these forms. In this study, two riparian soils (G and K) showing contrasting soil P speciation (65% of inorganic P species in soil G, as against 70% of organic P) were submitted to three successive dry/wet cycles in the laboratory. Conventional colorimetric determination of P concentrations combined with ultrafiltration, and measurements of iron (Fe) and aluminum (Al) and dissolved organic carbon (DOC) contents using ICP-MS and TOC analyzers, respectively, were used to study the response of the different P forms to rewetting after drying and also their release kinetics during soil leaching. For both soils, marked P release peaks were observed at the beginning of each wet cycles, with the organic-rich K soils giving, however, larger peaks than the inorganic one (G soil). For both soils also, concentrations in molybdate reactive P (MRP) remained quite constant throughout each leaching episode, contrary to the molybdate unreactive P (MUP) concentrations which were high immediately after rewetting and then decreased rapidly during leaching. A speciation change was observed from the beginning to the end of all leaching cycles. Colloidal P was found to be a major fraction of the total P immediately after rewetting (up to 50-70%) and then decreased to the end of each wet cycle where most of the eluted P was true dissolved inorganic P. Colloidal

  15. Soil moisture prediction to support management in semiarid wetlands during drying episodes

    NARCIS (Netherlands)

    Aguilera, Héctor; Moreno, Luis; Wesseling, Jan G.; Jiménez-Hernández, María E.; Castaño, Silvino

    2016-01-01

    Wetlands supported by groundwater in semiarid regions are extremely vulnerable to the impacts of droughts, particularly anthropized systems. During drying periods, soil water content arises as the controlling factor for environmental and ecological disturbances such as the spread of invasive

  16. Long-Term Effects of Multiwalled Carbon Nanotubes and Graphene on Microbial Communities in Dry Soil.

    Science.gov (United States)

    Ge, Yuan; Priester, John H; Mortimer, Monika; Chang, Chong Hyun; Ji, Zhaoxia; Schimel, Joshua P; Holden, Patricia A

    2016-04-05

    Little is known about the long-term effects of engineered carbonaceous nanomaterials (ECNMs) on soil microbial communities, especially when compared to possible effects of natural or industrial carbonaceous materials. To address these issues, we exposed dry grassland soil for 1 year to 1 mg g(-1) of either natural nanostructured material (biochar), industrial carbon black, three types of multiwalled carbon nanotubes (MWCNTs), or graphene. Soil microbial biomass was assessed by substrate induced respiration and by extractable DNA. Bacterial and fungal communities were examined by terminal restriction fragment length polymorphism (T-RFLP). Microbial activity was assessed by soil basal respiration. At day 0, there was no treatment effect on soil DNA or T-RFLP profiles, indicating negligible interference between the amended materials and the methods for DNA extraction, quantification, and community analysis. After a 1-year exposure, compared to the no amendment control, some treatments reduced soil DNA (e.g., biochar, all three MWCNT types, and graphene; P graphene); however, there were no significant differences across the amended treatments. These findings suggest that ECNMs may moderately affect dry soil microbial communities but that the effects are similar to those from natural and industrial carbonaceous materials, even after 1-year exposure.

  17. Dry air preservation and corrosion prevention using desiccant dehumidification

    International Nuclear Information System (INIS)

    Tykesson, M.; Ashworth, C.

    1991-01-01

    The preservation and longevity of power station plants is a significant problem, particularly in cold shut down situations for prolonged periods of time, and also in storage of parts prior to installation. Power station protection and equipment preservation using the desiccant method is not new. For many years dehumidification machinery has been employed as a barrier to moisture related degradation. The first rotary desiccant dehumidifiers were installed within the power plant industry in the mid 1960s. Many of these first installations remain in operation today. In order to understand the functioning of a desiccant unit as compared with other air handling systems, it is essential to understand the fundamentals of a psychrometric chart. This article will attempt to give the reader an understanding of the subject. (author)

  18. Effect of microwave and air drying of parboiled rice on stabilization of rice bran oil

    Directory of Open Access Journals (Sweden)

    Rizk, Laila F.

    1995-06-01

    Full Text Available Two rice varieties, Giza 175 (short grain and Giza 181 (long grain were partDoiled by soaking the grains at room temperature for 20 hours and steaming for 15 min then dried either at room temperature or by microwave. The results indicated that air and microwave drying significantly increased oil extraction in both rice bran varieties. Parboiling followed by air or microwave drying produced a slight change on protein, fiber and ash content of rice bran and reduced the development of free fatty acids (F.F.A. In oil bran. Microwave samples have less F.F.A. content than the corresponding samples air dried. Oils from the cold stored rice bran presented lower F.F.A. than the corresponding oil bran stored at room temperature. The ratio between total unsaturated fatty acids and total saturated ones (Tu/Ts decreased after air and microwave drying. Results also show that air drying increased the ratio of total hydrocarbons and total sterols (Tu/Ts in both varieties while microwave decreased it.

    Dos variedades de arroz, Giza 175 (grano corto y Giza 181 (grano largo se precocieron mediante la puesta en remojo de los granos a temperatura ambiente durante 20 horas y cocimiento al vapor durante 15 minutos, luego se secaron a temperatura ambiente o por microondas. Los resultados indicaron que el secado al aire y en microondas aumentó significativamente la extracción del aceite en ambas variedades de salvado de arroz. El precocido seguido del secado al aire o en microondas produjo un cambio pequeño en el contenido en proteína, fibra y ceniza y redujo el desarrollo de ácidos grasos libres (F.F.A. en el aceite de salvado. Las muestras secadas en microondas tuvieron un menor contenido en F.F.A. que las muestras correspondientes al secado en aire. Aceites de salvado de arroz almacenado en frió presentaron menor F.F.A. que los almacenados a temperatura ambiente. La relación entre ácidos grasos insaturados totales y los saturados totales (Tu/Ts disminuy

  19. Negative soil moisture-precipitation feedback in dry and wet regions.

    Science.gov (United States)

    Yang, Lingbin; Sun, Guoqing; Zhi, Lu; Zhao, Jianjun

    2018-03-05

    Soil moisture-precipitation (SM-P) feedback significantly influences the terrestrial water and energy cycles. However, the sign of the feedback and the associated physical mechanism have been debated, leaving a research gap regarding global water and climate changes. Based on Koster's framework, we estimate SM-P feedback using satellite remote sensing and ground observation data sets. Methodologically, the sign of the feedback is identified by the correlation between monthly soil moisture and next-month precipitation. The physical mechanism is investigated through coupling precipitation and soil moisture (P-SM), soil moisture ad evapotranspiration (SM-E) and evapotranspiration and precipitation (E-P) correlations. Our results demonstrate that although positive SM-P feedback is predominant over land, non-negligible negative feedback occurs in dry and wet regions. Specifically, 43.75% and 40.16% of the negative feedback occurs in the arid and humid climate zones. Physically, negative SM-P feedback depends on the SM-E correlation. In dry regions, evapotranspiration change is soil moisture limited. In wet regions, evapotranspiration change is energy limited. We conclude that the complex SM-E correlation results in negative SM-P feedback in dry and wet regions, and the cause varies based on the environmental and climatic conditions.

  20. Modeling Soil Water Retention Curves in the Dry Range Using the Hygroscopic Water Content

    DEFF Research Database (Denmark)

    Chen, Chong; Hu, Kelin; Arthur, Emmanuel

    2014-01-01

    Accurate information on the dry end (matric potential less than −1500 kPa) of soil water retention curves (SWRCs) is crucial for studying water vapor transport and evaporation in soils. The objectives of this study were to assess the potential of the Oswin model for describing the water adsorption...... curves of soils and to predict SWRCs at the dry end using the hygroscopic water content at a relative humidity of 50% (θRH50). The Oswin model yielded satisfactory fits to dry-end SWRCs for soils dominated by both 2:1 and 1:1 clay minerals. Compared with the Oswin model, the Campbell and Shiozawa model...... for soils dominated by 2:1 and 1:1 clays, respectively. Comparison of the Oswin model combined with the Kelvin equation, with water potential estimated from θRH50 (Oswin-KRH50), CS model combined with the Arthur equation (CS-A), and CS-K model, with water potential obtained from θRH50 (CS-KRH50) indicated...

  1. Thin layer convective air drying of wild edible plant (Allium roseum) leaves: experimental kinetics, modeling and quality.

    Science.gov (United States)

    Ben Haj Said, Leila; Najjaa, Hanen; Farhat, Abdelhamid; Neffati, Mohamed; Bellagha, Sihem

    2015-06-01

    The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant factor during drying of Allium roseum leaves. Five models selected from the literature were found to satisfactorily describe drying kinetics of Allium roseum leaves for all tested drying conditions. Drying data were analyzed to obtain moisture diffusivity values. During the falling rate-drying period, moisture transfer from Allium roseum leaves was described by applying the Fick's diffusion model. Moisture diffusivity varied from 2.55 × 10(-12) to 8.83 × 10(-12) m(2)/s and increased with air temperature. Activation energy during convective drying was calculated using an exponential expression based on Arrhenius equation and ranged between 46.80 and 52.68 kJ/mol. All sulfur compounds detected in the fresh leaves were detected in the dried leaves. Convective air drying preserved the sulfur compounds potential formation.

  2. Three air quality studies: Great Lakes ozone formation and nitrogen dry deposition; and Tucson aerosol chemical characterization

    Science.gov (United States)

    Foley, Theresa

    (arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, and nickel) in the southern Tucson metropolitan area. A Tucson company that uses beryllium oxide to manufacture thermally conductive ceramics has prompted strong citizen concern. This study found that the study area has good air quality with respect to PM10 and metals, with ambient concentrations meeting US Environmental Protection Agency and World Health Organization standards. Beryllium was detected only once (during a dust storm) and was ascribed to naturally-occurring beryllium in the suspended soil. The third paper (to be submitted to the Journal of Great Lakes Research) studies nitrogen dry deposition over Lake Michigan and Lake Superior. Numerous studies have shown that wet and dry deposition of nitrogen has contributed to the eutrophication of coastal waters and declining productivity of marine fisheries. Nitrogen dry deposition over the Great Lakes themselves, as opposed to the shorelines, has not been documented in the peer-reviewed literature. This paper calculates nitrogen dry deposition over Lake Michigan and Lake Superior, using aircraft measurements from the LADCO Aircraft Study, and finds that over-water, nitrogen dry deposition is a significant source of nitrogen to Lake Michigan and Lake Superior.

  3. Impact of drying-rewetting events on the response of soil microbial functions to dairyfibre and Miscanthus biochars

    Science.gov (United States)

    Bonnett, Sam; Vink, Stefanie; Baker, Kate; Saghir, Muhammad; Hornung, Andreas

    2014-05-01

    Biochar application has been shown to positively affect soil microbial functions such as reducing greenhouse gas emissions, increasing water/nutrient availability and increasing crop yields in tropical regions (Lehmann & Joseph, 2009). Understanding the dynamics of biochar application to soil microbial processes is critical for ensuring that soil quality, integrity and sustainability of the soil sub-system are maintained for crop growth. The aim of this British Ecological Society (BES) funded study was to examine the effect of two types of biochar on soil physicochemistry, GHG production, soil enzyme activities and microbial biomass in typical agricultural soil types and whether the effects were altered by drying, rewetting and flooding events. Miscanthus and dairyfibre (a mixture of straw and manure) feedstocks from Harper Adams University were pyrolyzed by Aston University at 450 °C using 100 kg/hr pyroformer technology. Two sieved soil types (sandy loam and clay loam) were mixed with dry biochar to produce 2 and 10 % w/w treatments for comparison with controls and maintained at 15 °C in temperature controlled incubators. At 0, 22, 44, 80, 101, and 114 days, soil was collected for determination of heterotrophic respiration, and microbial biomass by substrate-induced respiration (SIR), by gas headspace incubation and analysis of carbon dioxide (CO2) and nitrous oxide (N2O) by gas chromatography. Soil was sampled for the determination of water-extractable carbon, pH, and extracellular enzyme activities. Soil samples were maintained at field gravimetric water content between 0 and 44 days; air dried between 44 and 80 days; rewetted between 80 and 101 days; and flooded between 101 to 114 days. Results showed that the impact of biochar on soil microbial processes was dependent on biochar type and soil type, the level of biochar application and changes in soil moisture. Biochar affected soil pH particularly within the dairyfibre treatments, potentially due to the

  4. Application of the biological forced air soil treatment (BIOFAST trademark) technology to diesel contaminated soil

    International Nuclear Information System (INIS)

    Lyons, K.A.; Leavitt, M.E.; Graves, D.A.; Stanish, S.M.

    1993-01-01

    A subsurface Biological Forced Air Soil Treatment (BIOFAST trademark) system was constructed at the Yellow Freight System, Inc. (Yellow Freight) New Haven facility in Connecticut as a means of expediting the remediation of soils impacted by a diesel fuel release. Prior to beginning construction activities the soils were evaluated for the feasibility of bioremediation based on soil characteristics including contaminant degrading bacteria, moisture content, and pH. Based on results of stimulant tests with oxygen and nutrients, the addition of fertilizer during the construction of the cell was recommended. Following the removal of underground storage tanks, the bioremediation cell was constructed by lining the enlarged excavation with high density polyethylene (HDPE) and backfilling alternating layers of nutrient-laden soil and pea gravel. Passive and active soil vapor extraction (SVE) piping was included in the gravel layers and connected to a blower and vapor treatment unit, operated intermittently to supply oxygen to the subsurface cell. Operating data have indicated that the bacteria are generating elevated levels of CO 2 , and the SVE unit is evacuating the accumulated CO 2 from the soils and replacing it with fresh air. These data suggest that the bioremediation process is active in the soils. Soil samples collected from within the soil pit subsequent to installation and again after 10 months of operation indicate that TPH concentrations have decreased by as much as 50%

  5. Influence of Disturbance on Soil Respiration in Biologically Crusted Soil during the Dry Season

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2013-01-01

    Full Text Available Soil respiration (Rs is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer. We measured Rs in three types of disturbed and undisturbed crusted soils (algae, lichen, and moss, as well as bare land from April to August, 2010, in Mu Us desert, northwest China. Rs was similar among undisturbed soils but increased significantly in disturbed moss and algae crusted soils. The variation of Rs in undisturbed and disturbed soil was related to soil bulk density. Disturbance also led to changes in soil organic carbon and fine particles contents, including declines of 60–70% in surface soil C and N, relative to predisturbance values. Once BSCs were disturbed, Q10 increased. Our findings indicate that a loss of BSCs cover will lead to greater soil C loss through respiration. Given these results, understanding the disturbance sensitivity impact on Rs could be helpful to modify soil management practices which promote carbon sequestration.

  6. Organochlorine pesticides in soils of Mexico and the potential for soil-air exchange.

    Science.gov (United States)

    Wong, Fiona; Alegria, Henry A; Bidleman, Terry F

    2010-03-01

    The spatial distribution of organochlorine pesticides (OCs) in soils and their potential for soil-air exchange was examined. The most prominent OCs were the DDTs (Geometric Mean, GM=1.6 ng g(-1)), endosulfans (0.16 ng g(-1)), and toxaphenes (0.64 ng g(-1)). DDTs in soils of southern Mexico showed fresher signatures with higher FDDTe=p,p'-DDT/(p,p'-DDT+p,p'-DDE) and more racemic o,p'-DDT, while the signatures in the central and northern part of Mexico were more indicative of aged residues. Soil-air fugacity fractions showed that some soils are net recipients of DDTs from the atmosphere, while other soils are net sources. Toxaphene profiles in soils and air showed depletion of Parlar 39 and 42 which suggests that soil is the source to the atmosphere. Endosulfan was undergoing net deposition at most sites as it is a currently used pesticide. Other OCs showed wide variability in fugacity, suggesting a mix of net deposition and volatilization. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  7. DEHYDRATION OF CHEESE BY HOT AIR, MICROWAVE AND FREEZE-DRYING

    Directory of Open Access Journals (Sweden)

    ANA RITA C. PINHO

    2017-12-01

    Full Text Available The objective of this work was to study the dehydration of skim cheese through different methods, in particular by hot air, microwave and freeze-drying, in order to assess which of these methods would be more suitable for the development of a new product (cheese snack. For the three processes of dehydration, several temperatures, powers and times were used, respectively. The drying time was optimized to allow the water activity of the final product to be between 0.3 and 0.4. The color and texture of the product obtained by the three processes were evaluated, and the nutritional analysis (protein, lipids, ash of the product dried by hot air at 52 ºC and by microwave at 750 W and 850 W was performed. The sensory analysis of the microwave dehydrated products was also carried out. The results obtained revealed that the temperature played a relevant role in the drying time and the hardness of the product. In the dehydration by microwave, the power of 850 W resulted in a lower drying time and a better color preservation, but in a high hardness of the samples. Among the three processes studied, the microwave drying was the fastest for the water removal from the cheese.

  8. Effect of heterogenous and homogenous air gaps on dry heat loss through the garment

    Science.gov (United States)

    Mert, Emel; Psikuta, Agnes; Bueno, Marie-Ange; Rossi, René M.

    2015-11-01

    In real life conditions, the trapped air between the human body and the garment has uneven shape and vary over the body parts as a consequence of the complex geometry of the human body. However, the existing clothing models assume uniform air layer between the human body and the garment or its full contact, which may cause large error in the output of simulations. Therefore, the aim of this study was to investigate the effect of a heterogeneous vertical air gap with different configuration of folds (size and frequency) on dry heat loss using a heated cylinder (Torso). It was found that the presence of folds in the garment led to an increased heat loss from the body in comparison to a homogeneous air gap of comparable size. Interestingly, the size of folds did not have an influence on the dry heat loss. Additionally, the effect of the contact area on dry heat loss became important when exceeding a threshold of about 42 %. The results from this study are useful for modelling of a realistic dry heat loss through the clothing and contribute to the improvement of design of protective and active sport garments.

  9. Humidifying system design of PEMFC test platform based on the mixture of dry and wet air

    Directory of Open Access Journals (Sweden)

    Tiancai Ma

    2015-01-01

    Full Text Available Based on the present humidifying system of PEMFC test platform, a novel design based on dry and wet air mixture is proposed. Key parameters are calculated, and test platform is built. Three experiments are implemented to test the performance of proposed design. Results show that the new design can meet the requirements, and realize the quick response and accurate control.

  10. Microwave assisted air drying of osmotically treated pineapple with variable power programmes

    CSIR Research Space (South Africa)

    Botha, GE

    2012-01-01

    Full Text Available Variable power programmes for microwave assisted air drying of pineapple were studied. The pineapple pieces were pre-treated by osmotic dehydration in a 55º Brix sucrose solution at 40ºC for 90 minutes. Variable power output programmes were designed...

  11. Dry purification of aspirational air in coke-sorting systems with wet slaking of coke

    Energy Technology Data Exchange (ETDEWEB)

    T.F. Trembach; A.G. Klimenko [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

    2009-07-15

    Coke transportation after wet slaking is accompanied by the release of dust in the production building and in the surrounding atmosphere. Wet methods are traditionally used to purify very humid air. Giprokoks has developed designs for highly efficient dry dust-removal methods in such conditions.

  12. Radioecological investigations in the food-chain air-soil-vine-wine. Pt. 1

    International Nuclear Information System (INIS)

    Wagner, A.; Hellmuth, K.H.; Fischer, E.

    1988-12-01

    In a field investigation (1983-1985) comprising 8 locations of the most important viticultural regions in Germany, the contents of H-3, C-14, Sr-90, and Cs-137 in air, soils, leaves of the vine, grapes and wine were measured and site-specific transfer factors were calculated. Data concerning soil parameters, climatic conditions, cultivation and vinification were collected. The T contents of all samples were 10 Bq/l water of combustion, independent of location and year. The specific activity of C-14 in the atmosphere and in biological material was 0.22 Bq/g C, independent of site and year. Sr-90 contents of soils fluctuated between 0.7 and 3.5 Bq/kg dry matter. The mean content of leaves was 2 Bq/kg fresh material, of grapes 0.035 Bq/kg and of wine 0.008 Bq/l. The Cs-137 level of soils fluctuated between 1.3 and 7.9 Bq/kg dry matter. The mean content of leaves was 0.098 Bq/kg fresh material, of grapes 0.021 Bq/kg and of wine 0.0085 Bq/l. A relation between transfer and soil parameters and between the contents of grapes and wine was not recognizeable. While cultivar-specific differences were not observed in grapes, red wines contained somewhat more Cs-137 than white wines. Transfer factors soil-grapes were 0.027 for Sr-90 and 0.0057 for Cs-137. Site-specific influences such as soil parameters, climate, cultivation, vinification and differences between years led to a small fluctuation of values. No influence of the Neckarwestheim reactor has been found in any of the radionuclides. (orig./HP) [de

  13. Economical analysis of the spray drying process by pre-dehumidification of the inlet air

    Energy Technology Data Exchange (ETDEWEB)

    Madeira, A.N.; Camargo, J.R. [University of Taubate (UNITAU), SP (Brazil). Mechanical Engineering Dept.

    2009-07-01

    Spray drying is a dehumidification process by atomization in a closed chamber that aims to remove moisture of a product by heat and mass transfer from the product's contained water to the air that, in this process is previously heated. This paper presents a case study for an industry that produces food ingredients. The current process applied in the product to heat the air can uses one of these two systems: a direct heating process that burns liquid petroleum gas in contact with the inlet air or indirect heating that uses a heat exchanger which heat the air. This heating system consumes 90% of the total process energy. However, this inlet air can reach the dehumidifier with high moisture from the atmosphere condition requesting, in this case, more energy consumption according to the year's seasons. This paper promotes a utilization study of the current process through the installation of a pre-dehumidification device of the inlet air and shows a study to three different dehumidification systems that means by refrigeration, adsorption and actual comparing their performance in an energetic and economical point of view. The goals of this study are to analyze the capacity of moisture removing of each removing device, the influence of moisture variation of the inlet air in the process as well as the economic impact of each device in the global system. It concludes that the utilization of dehumidification devices can eliminate the heating system reducing this way the energy consumption. Moreover it promotes the increasing of moisture gradient between the inlet air and the product optimizing the drying process and increasing the global energy efficiency in the global system. Choosing the most appropriate system for the pre-dehumidification device depends on the desired initial and final moisture content of the product, but applying pre-dehumidifiers at the inlet air promotes an energetic optimization in the spray drying process. (author)

  14. Coffee husk associated with firewood as fuel for indirect heating of drying air

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Edney Alves; Silva, Juarez de Sousa e; Silva, Jadir Nogueira da; Oliveira Filho, Delly [Universidade Federal de Vicosa (DEA/UFV), MG (Brazil). Dept. de Engenharia Agricola; Donzeles, Sergio Mauricio Lopes [Empresa de Pesquisa Agropecuaria de Minas Gerais (EPAMIG), Vicosa, MG (Brazil)

    2008-07-01

    The objective of this work was the performance analysis of a furnace, burning coffee husk associated with firewood to heat the drying air passing through a heat exchanger. For the analysis the temperature variation, the combustion quality, the heat losses and the furnace thermal efficiency were all monitored. Results showed that the furnace average efficiency was 58.3% and the heat losses in the exhaust were 24.3%. The presence of carbon monoxide in the exhaust gases (average 2982.8 ppm) had proven incomplete combustion, and suggesting that the combustion gases can not be used to directly drying of foods. Despite of indirect heating, the presented thermal efficiency indicates that the burning of coffee husks is one economic alternative for air heating in grain drying or in other agricultural processes. (author)

  15. Soil and air temperatures for different habitats in Mount Rainier National Park.

    Science.gov (United States)

    Sarah E. Greene; Mark Klopsch

    1985-01-01

    This paper reports air and soil temperature data from 10 sites in Mount Rainier National Park in Washington State for 2- to 5-year periods. Data provided are monthly summaries for day and night mean air temperatures, mean minimum and maximum air temperatures, absolute minimum and maximum air temperatures, range of air temperatures, mean soil temperature, and absolute...

  16. Cold Vacuum Drying facility heating, ventilation, and Air Conditioning system design description

    International Nuclear Information System (INIS)

    SINGH, G.

    2000-01-01

    This System Design Description (SDD) addresses the HVAC system for the CVDF. The CVDF HVAC system consists of five subsystems: (1) Administration building HVAC system; (2) Process bay recirculation HVAC system; (3) Process bay local exhaust HVAC and process vent system; (4) Process general supply/exhaust HVAC system; and (5) Reference air system. The HVAC and reference air systems interface with the following systems: the fire protection control system, Monitoring and Control System (MCS), electrical power distribution system (including standby power), compressed air system, Chilled Water (CHW) system, drainage system, and other Cold Vacuum Drying (CVD) control systems not addressed in this SDD

  17. External exposure to radionuclides in air, water, and soil

    International Nuclear Information System (INIS)

    Eckerman, K.F.; Ryman, J.C.

    1996-01-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body

  18. Radon diffusion studies in air, gravel, sand, soil and water

    International Nuclear Information System (INIS)

    Singh, B.; Singh, S.; Virk, H.S.

    1993-01-01

    Radon isotopes are practically inert and have properties of gases under conditions of geological interest. During their brief lives their atoms are capable of moving from sites of their generation. Radon diffusion studies were carried out in air, gravel, sand, soil and water using silicon diffused junction electronic detector, Alphameter-400. Diffusion constant and diffusion length is calculated for all these materials. (author)

  19. Effect of additives and steaming on quality of air dried noodles.

    Science.gov (United States)

    Gatade, Abhijeet Arun; Sahoo, Akshaya Kumar

    2015-12-01

    Texture is the most important property for consumer acceptance in cooked noodles. The air dried noodles are known to have higher cooking loss and cooking time, to that of instant fried noodles. But the fat content of instant fried noodles is more. In the present work attempts were made to optimize the moisture content so as to obtain a smooth dough for extruded noodle preparation and develop air dried noodles of low fat content with lesser cooking loss and cooking time. To meet the objectives, the effect of various additives and steaming treatment on cooking quality, sensory attributes, textural properties and microstructure of noodles were studied. Dough prepared by addition of 40 ml water to 100 g flour resulted into formation of a soft dough, leading to production of noodles of improved surface smoothness and maximum yield. The use of additives (5 g oil, 0.2 g guar gum, 2 g gluten and 1 ml of 1 % kansui solution for 100 g of flour) and steaming treatment showed significant effect on noodles quality, with respect to cooking characteristics, sensory attributes and textural properties. The microstructure images justified the positive correlation between the effects of ingredients with steaming and quality parameters of noodles. Air dried noodles with reduced cooking loss (~50 % reduction) with marginal reduction in cooking time was developed, which were having similar characteristics to that of instant fried noodles. Compared to the instant fried noodle, the prepared air dried noodle was having substantially reduced fat content (~70 % reduction). Thus the present study will be useful for guiding extrusion processes for production of air dried noodles having less cooking time and low fat content.

  20. Preliminary Design of KAIST Micro Modular Reactor with Dry Air Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seung Joon; Bae, Seong Jun; Kim, Seong Gu; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    KAIST research team recently proposed a Micro Modular Reactor (MMR) concept which integrates power conversion unit (PCU) with the reactor core in a single module. Using supercritical CO{sub 2} as a working fluid of cycle can achieve physically compact size due to small turbomachinery and heat exchangers. The objective of this project is to develop a concept that can operate at isolated area. The design focuses especially on the operation in the inland area where cooling water is insufficient. Thus, in this paper the potential for dry air cooling of the proposed reactor will be examined by sizing the cooling system with preliminary approach. The KAIST MMR is a recently proposed concept of futuristic SMR. The MMR size is being determined to be transportable with land transportation. Special attention is given to the MMR design on the dry cooling, which the cooling system does not depend on water. With appropriately designed air cooling heat exchanger, the MMR can operate autonomously. Two types of air cooling methods are suggested. One is using fan and the other is utilizing cooling tower for the air flow. With fan type air cooling method it consumes about 0.6% of generated electricity from the nuclear reactor. Cooling tower occupies an area of 227 m{sup 2} and 59.6 m in height. This design is just a preliminary estimation of the dry cooling method, and therefore more detailed and optimal design will be followed in the next phase.

  1. Temperature Control of Heating Zone for Drying Process: Effect of Air Velocity Change

    Directory of Open Access Journals (Sweden)

    Wutthithanyawat Chananchai

    2016-01-01

    Full Text Available This paper proposes a temperature control technique to adjust air temperature in a heating zone for drying process. The controller design is achieved by using an internal model control (IMC approach. When the IMC controller parameters were designed by calculating from an actual process transfer function estimated through an open-loop step response with input step change from 50% to 60% at a reference condition at air velocity of 1.20 m/s, the performance of temperature controller was experimentally tested by varying an air velocity between 1.32 m/s and 1.57 m/s, respectively. The experimental results showed that IMC controller had a high competency for controlling the drying temperature.

  2. Dry air effects on the copper oxides sensitive layers formation for ethanol vapor detection

    International Nuclear Information System (INIS)

    Labidi, A.; Bejaoui, A.; Ouali, H.; Akkari, F. Chaffar; Hajjaji, A.; Gaidi, M.; Kanzari, M.; Bessais, B.; Maaref, M.

    2011-01-01

    The copper oxide films have been deposited by thermal evaporation and annealed under ambient air and dry air respectively, at different temperatures. The structural characteristics of the films were investigated by X-ray diffraction. They showed the presences of two hydroxy-carbonate minerals of copper for annealing temperatures below 250 deg. C. Above this temperature the conductivity measurements during the annealing process, show a transition phase from metallic copper to copper oxides. The copper oxides sensitivity toward ethanol were performed using conductivity measurements at the working temperature of 200 deg. C. A decrease of conductivity was observed under ethanol vapor, showing the p-type semi-conducting characters of obtained copper oxide films. It was found that the sensing properties of copper oxide toward ethanol depend mainly on the annealing conditions. The best responses were obtained with copper layers annealed under dry air.

  3. Dry air effects on the copper oxides sensitive layers formation for ethanol vapor detection

    Energy Technology Data Exchange (ETDEWEB)

    Labidi, A., E-mail: Ahmed_laabidi@yahoo.fr [URPSC (UR 99/13-18) Unite de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, Universite de Carthage, BP 51, La Marsa 2070, Tunis (Tunisia); Bejaoui, A.; Ouali, H. [URPSC (UR 99/13-18) Unite de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, Universite de Carthage, BP 51, La Marsa 2070, Tunis (Tunisia); Akkari, F. Chaffar [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs, ENIT, Universite de Tunis el Manar, BP 37, Le belvedere 1002, Tunis (Tunisia); Hajjaji, A.; Gaidi, M. [Laboratoire de Photovoltaique, Centre de Recherches et de technologies de l' energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia); Kanzari, M. [Laboratoire de Photovoltaique et Materiaux Semi-conducteurs, ENIT, Universite de Tunis el Manar, BP 37, Le belvedere 1002, Tunis (Tunisia); Bessais, B. [Laboratoire de Photovoltaique, Centre de Recherches et de technologies de l' energie, Technopole de Borj-Cedria, BP 95, 2050 Hammam-Lif (Tunisia); Maaref, M. [URPSC (UR 99/13-18) Unite de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, Universite de Carthage, BP 51, La Marsa 2070, Tunis (Tunisia)

    2011-09-15

    The copper oxide films have been deposited by thermal evaporation and annealed under ambient air and dry air respectively, at different temperatures. The structural characteristics of the films were investigated by X-ray diffraction. They showed the presences of two hydroxy-carbonate minerals of copper for annealing temperatures below 250 deg. C. Above this temperature the conductivity measurements during the annealing process, show a transition phase from metallic copper to copper oxides. The copper oxides sensitivity toward ethanol were performed using conductivity measurements at the working temperature of 200 deg. C. A decrease of conductivity was observed under ethanol vapor, showing the p-type semi-conducting characters of obtained copper oxide films. It was found that the sensing properties of copper oxide toward ethanol depend mainly on the annealing conditions. The best responses were obtained with copper layers annealed under dry air.

  4. Earth System Models Underestimate Soil Carbon Diagnostic Times in Dry and Cold Regions.

    Science.gov (United States)

    Jing, W.; Xia, J.; Zhou, X.; Huang, K.; Huang, Y.; Jian, Z.; Jiang, L.; Xu, X.; Liang, J.; Wang, Y. P.; Luo, Y.

    2017-12-01

    Soils contain the largest organic carbon (C) reservoir in the Earth's surface and strongly modulate the terrestrial feedback to climate change. Large uncertainty exists in current Earth system models (ESMs) in simulating soil organic C (SOC) dynamics, calling for a systematic diagnosis on their performance based on observations. Here, we built a global database of SOC diagnostic time (i.e.,turnover times; τsoil) measured at 320 sites with four different approaches. We found that the estimated τsoil was comparable among approaches of 14C dating () (median with 25 and 75 percentiles), 13C shifts due to vegetation change () and the ratio of stock over flux (), but was shortest from laboratory incubation studies (). The state-of-the-art ESMs underestimated the τsoil in most biomes, even by >10 and >5 folds in cold and dry regions, respectively. Moreover,we identified clear negative dependences of τsoil on temperature and precipitation in both of the observational and modeling results. Compared with Community Land Model (version 4), the incorporation of soil vertical profile (CLM4.5) could substantially extend the τsoil of SOC. Our findings suggest the accuracy of climate-C cycle feedback in current ESMs could be enhanced by an improved understanding of SOC dynamics under the limited hydrothermal conditions.

  5. Short-term dynamics of culturable bacteria in a soil amended with biotransformed dry olive residue.

    Science.gov (United States)

    Siles, J A; Pascual, J; González-Menéndez, V; Sampedro, I; García-Romera, I; Bills, G F

    2014-03-01

    Dry olive residue (DOR) transformation by wood decomposing basidiomycetes (e.g. Coriolopsis floccosa) is a possible strategy for eliminating the liabilities related to the use of olive oil industry waste as an organic soil amendment. The effects of organic fertilization with DOR on the culturable soil microbiota are largely unknown. Therefore, the objectives of this study were to measure the short-term effects of DOR and C. floccosa-transformed DOR on the culturable bacterial soil community, while at the same time documenting the bacterial diversity of an agronomic soil in the southeastern Iberian Peninsula. The control soil was compared with the same soil treated with DOR and with C. floccosa-transformed DOR for 0, 30 and 60 days. Impact was measured from total viable cells and CFU counts, as well as the isolation and characterization of 900 strains by fatty acid methyl ester profiles and 16S rRNA partial sequencing. The bacterial diversity was distributed between Actinobacteria, Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Bacilli, Sphingobacteria and Cytophagia. Analysis of the treatments and controls demonstrated that soil amendment with untransformed DOR produced important changes in bacterial density and diversity. However, when C. floccosa-transformed DOR was applied, bacterial proliferation was observed but bacterial diversity was less affected, and the distribution of microorganisms was more similar to the unamended soil. Copyright © 2013 Elsevier GmbH. All rights reserved.

  6. Chemistry and Mineralogy of Antarctica Dry Valley Soils: Implications for Mars

    Science.gov (United States)

    Quinn, J. E.; Golden, D. C.; Graff, T. G.; Ming, D. W.; Morris, R. V.; Douglas, S.; Kounaves, S. P.; McKay, C. P.; Tamppari, L, K.; Smith, P. H.; hide

    2011-01-01

    The Antarctic Dry Valleys (ADV) comprise the largest ice-free region of Antarctica. Precipitation almost always occurs as snow, relative humidity is frequently low, and mean annual temperatures are about -20 C. The ADV soils have previously been categorized into three soil moisture regimes: subxerous, xerous and ultraxerous, based on elevation and climate influences. The subxerous regime is predominately a coastal zone soil, and has the highest average temperature and precipitation, while the ultraxerous regime occurs at high elevation (>1000 m) and have very low temperature and precipitation. The amounts and types of salts present in the soils vary between regions. The nature, origin and significance of salts in the ADV have been previously investigated. Substantial work has focused on soil formation in the ADVs, however, little work has focused on the mineralogy of secondary alteration phases. The dominant weathering process in the ADV region is physical weathering, however, chemical weathering has been well documented. The objective of this study was to characterize the chemistry and mineralogy, including the alteration mineralogy, of soils from two sites, a subxerous soil in Taylor Valley, and an ultraxerous soil in University Valley. The style of aqueous alteration in the ADVs may have implications for pedogenic processes on Mars.

  7. Using Artificial Soil and Dry-Column Flash Chromatography to Simulate Organic Substance Leaching Process: A Colorful Environmental Chemistry Experiment

    Science.gov (United States)

    de Avellar, Isa G. J.; Cotta, Tais A. P. G.; Neder, Amarilis de V. Finageiv

    2012-01-01

    Soil is an important and complex environmental compartment and soil contamination contributes to the pollution of aquifers and other water basins. A simple and low-cost experiment is described in which the mobility of three organic compounds in an artificial soil is examined using dry-column flash chromatography. The compounds were applied on top…

  8. New species of ice nucleating fungi in soil and air

    Science.gov (United States)

    Fröhlich-Nowoisky, Janine; Hill, Thomas C. J.; Pummer, Bernhard G.; Franc, Gray D.; Pöschl, Ulrich

    2014-05-01

    Primary biological aerosol particles (PBAP) are ubiquitous in the atmosphere (1,2). Several types of PBAP have been identified as ice nuclei (IN) that can initiate the formation of ice at relatively high temperatures (3, 4). The best-known biological IN are common plant-associated bacteria. The IN activity of these bacteria is due to a surface protein on the outer cell membrane that catalyses ice formation, for which the corresponding gene has been identified and detected by DNA analysis (3). Fungal spores or hyphae can also act as IN, but the biological structures responsible for their IN activity have not yet been elucidated. Furthermore, the abundance, diversity, sources, seasonality, properties, and effects of fungal IN in the atmosphere have neither been characterized nor quantified. Recent studies have shown that airborne fungi are highly diverse (1), and that atmospheric transport leads to efficient exchange of species among different ecosystems (5, 6). The results presented in Fröhlich-Nowoisky et al. 2012 (7) clearly demonstrate the presence of geographic boundaries in the global distribution of microbial taxa in air, and indicate that regional differences may be important for the effects of microorganisms on climate and public health. DNA analyses of aerosol samples collected during rain events showed higher diversity and frequency of occurrence for fungi belonging to the Sordariomycetes, than samples that were collected under dry conditions (8). Sordariomycetes is the class that comprises known ice nucleation active species (Fusarium spp.). By determination of freezing ability of fungal colonies isolated from air samples two species of ice nucleation active fungi that were not previously known as biological ice nucleators were found. By DNA-analysis they were identified as Isaria farinosa and Acremonium implicatum. Both fungi belong to the phylum Ascomycota, produce fluorescent spores in the range of 1-4 µm in diameter, and induced freezing at -4 and

  9. Levels, distribution and air-soil exchange fluxes of polychlorinated biphenyls (PCBs) in the environment of Punjab Province, Pakistan.

    Science.gov (United States)

    Syed, Jabir Hussain; Malik, Riffat Naseem; Li, Jun; Zhang, Gan; Jones, Kevin C

    2013-11-01

    An initial survey of the concentrations of polychlorinated biphenyl (PCB) compounds in air and soils across industrial and agricultural areas of Punjab Province, Pakistan, was conducted from January to March 2011. The total concentration of all PCBs (31 PCBs) ranged from 34 to 389pgm(-3) in air and from 7 to 45ngg(-1) dry weight in soils, where both ranges were similar to the average ranges in other areas of the world. PCBs were elevated across industrial regions near urban and industrial sources. Consistently low air concentrations of PCBs at the agricultural sites suggest that they are less widespread or uniformly distributed in the Pakistani atmosphere. The calculated air and soil fugacity fraction values indicated that soils are a potential secondary source of PCBs in agricultural areas, whereas they are in equilibrium or atmospheric deposition in industrial and urban areas. TEQ concentrations of dioxin-like PCBs for soil samples met the Canadian standard. However, local authorities should address the human health threats from urban and industrial soils in Punjab Province, Pakistan. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. GEMAS: Colours of dry and moist agricultural soil samples of Europe

    Science.gov (United States)

    Klug, Martin; Fabian, Karl; Reimann, Clemens

    2016-04-01

    High resolution HDR colour images of all Ap samples from the GEMAS survey were acquired using a GeoTek Linescan camera. Three measurements of dry and wet samples with increasing exposure time and increasing illumination settings produced a set of colour images at 50μm resolution. Automated image processing was used to calibrate the six images per sample with respect to the synchronously measured X-Rite colorchecker chart. The calibrated images were then fit to Munsell soil colours that were measured in the same way. The results provide overview maps of dry and moist European soil colours. Because colour is closely linked to iron mineralogy, carbonate, silicate and organic carbon content the results can be correlated to magnetic, mineralogical, and geochemical properties. In combination with the full GEMAS chemical and physical measurements, this yields a valuable data set for calibration and interpretation of visible satellite colour data with respect to chemical composition and geological background, soil moisture, and soil degradation. This data set will help to develop new methods for world-wide characterization and monitoring of agricultural soils which is essential for quantifying geologic and human impact on the critical zone environment. It furthermore enables the scientific community and governmental authorities to monitor consequences of climatic change, to plan and administrate economic and ecological land use, and to use the data set for forensic applications.

  11. Morphological, sediment and soil chemical characteristics of dry tropical shallow reservoirs in the Southern Mexican Highlands

    Directory of Open Access Journals (Sweden)

    José Luis ARREDONDO-FIGUEROA

    2011-02-01

    Full Text Available The morphometry, sediment and soil chemical characteristics of eleven dry tropical shallow reservoirs situated in Southern Mexican Highlands were studied. The reservoirs are located at 1104 to 1183 meters above sea level in a sedimentary area. Seventeen morphometric and eight sediment and soil chemical parameters were measured. The results of the morphometric parameters showed that these reservoirs presented a soft and roughness bottom, with an ellipsoid form and a concave depression that permit the mix up of water and sediments, causing turbidity and broken thermal gradients; their slight slopes allowed the colonization of submerged macrophyte and halophyte plants and improved the incidence of sunlight on water surface increasing evaporation and primary productivity. Dry tropical shallow reservoirs have fluctuations in area, and volume according to the amount of rainfall, the effect of evaporation, temperature, lost volume for irrigation, and other causes. The sand-clay was the most important sediment texture and their values fluctuated with the flooded periods. The concentration-dilution cycle showed a direct relationship in the percentage of organic matter in the soil as well as with pH, soil nitrogen and phosphorus. El Tilzate, El Candelero and El Movil were related by the shore development and high concentrations of organic matter and nitrogen in the soil. Finally, we emphasize the importance of this study, in relation to possible future changes in morphometrical parameters as a consequence of human impact.

  12. Thin layer convective air drying of wild edible plant (Allium roseum) leaves: experimental kinetics, modeling and quality

    OpenAIRE

    Ben Haj Said, Leila; Najjaa, Hanen; Farhat, Abdelhamid; Neffati, Mohamed; Bellagha, Sihem

    2014-01-01

    The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant f...

  13. STATISTIC MODELING OF DRYING KINETHIC OF SPINACH LEAVES USING MICROWAVE AND HOT AIR METHODS

    OpenAIRE

    Mojtaba Nouri; Marzieh Vahdani; Shilan Rashidzadeh; Lukáš Hleba; Mohammad Ali Shariati

    2015-01-01

    The target of this study was to model of spinach leaves drying using microwave and hot air dryer. This test performed in combination treatment of temperatures (50°C, 60°C, and 70°C) and microwave (90, 180, 360, 600 and 900w) in 3 replications. Sample moisture measured within drying. All the results were fitted and analyzed with 8 mathematical models base on 3 parameters including determination (R2), Chi square(X2), root mean square errors(RSME). Results also revealed that temperature and micr...

  14. Optimum dry-cooling sub-systems for a solar air conditioner

    Science.gov (United States)

    Chen, J. L. S.; Namkoong, D.

    1978-01-01

    Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

  15. Oxidation mechanism of Fe–16Cr alloy as SOFC interconnect in dry/wet air

    International Nuclear Information System (INIS)

    Chen, Zhi-Yuan; Wang, Li-Jun; Li, Fu-Shen; Chou, Kuo-Chih

    2013-01-01

    Highlights: •A special thermodynamic description corresponding to the kinetics was applied. •We reported the relationships of degradation time with temperature and moisture. •”Turning time” in the Fe–16Cr alloy oxidation kinetic model was given. •The oxidation mechanism of Fe–16Cr alloy in the wet air was discussed. -- Abstract: Experimental study on the oxidation corrosions of Fe–16Cr alloy was carried out at 800–1100 °C under dry/wet air conditions. Faster oxidation rate was observed at higher temperature and water vapor content. The degradation time t d between two stages in oxidation process showed an exponential relationship with elevating corrosion temperature in dry air, and a linear relationship with the water content in the case of water vapor introduced to the system. The mechanism of oxidation corrosions of Fe–16Cr alloy was suggested by the Real Physical Picture (RPP) model. It was found that the break-away oxidation in stage II was controlled by diffusion at initial both in dry and wet air, then became linear with the exposure time, which implied that the oxidation rate was then controlled by chemical reaction of the interface between the metal and the oxidized scale. Moreover, the effect of water in the oxidation process is not only to supply more oxygen into system, but also to modify the structures of oxide scale due to the existence of hydrogen atom, which results in the accelerated corrosions

  16. Polyamines and ethylene interact in rice grains in response to soil drying during grain filling.

    Science.gov (United States)

    Chen, Tingting; Xu, Yunji; Wang, Jingchao; Wang, Zhiqin; Yang, Jianchang; Zhang, Jianhua

    2013-05-01

    This study tested the hypothesis that the interaction between polyamines and ethylene may mediate the effects of soil drying on grain filling of rice (Oryza sativa L.). Two rice cultivars were pot grown. Three treatments, well-watered, moderate soil drying (MD), and severe soil drying (SD), were imposed from 8 d post-anthesis until maturity. The endosperm cell division rate, grain-filling rate, and grain weight of earlier flowering superior spikelets showed no significant differences among the three treatments. However, those of the later flowering inferior spikelets were significantly increased under MD and significantly reduced under SD when compared with those which were well watered. The two cultivars showed the same tendencies. MD increased the contents of free spermidine (Spd) and free spermine (Spm), the activities of S-adenosyl-L-methionine decarboxylase and Spd synthase, and expression levels of polyamine synthesis genes, and decreased the ethylene evolution rate, the contents of 1-aminocylopropane-1-carboxylic acid (ACC) and hydrogen peroxide, the activities of ACC synthase, ACC oxidase, and polyamine oxidase, and the expression levels of ethylene synthesis genes in inferior spikelets. SD exhibited the opposite effects. Application of Spd, Spm, or an inhibitor of ethylene synthesis to rice panicles significantly reduced ethylene and ACC levels, but significantly increased Spd and Spm contents, grain-filling rate, and grain weight of inferior spikelets. The results were reversed when ACC or an inhibitor of Spd and Spm synthesis was applied. The results suggest that a potential metabolic interaction between polyamines and ethylene biosynthesis responds to soil drying and mediates the grain filling of inferior spikelets in rice.

  17. Air drying modelling of Mastocarpus stellatus seaweed a source of hybrid carrageenan

    Science.gov (United States)

    Arufe, Santiago; Torres, Maria D.; Chenlo, Francisco; Moreira, Ramon

    2018-01-01

    Water sorption isotherms from 5 up to 65 °C and air drying kinetics at 35, 45 and 55 °C of Mastocarpus stellatus seaweed were determined. Experimental sorption data were modelled using BET and Oswin models. A four-parameter model, based on Oswin model, was proposed to estimate equilibrium moisture content as function of water activity and temperature simultaneously. Drying experiments showed that water removal rate increased significantly with temperature from 35 to 45 °C, but at higher temperatures drying rate remained constant. Some chemical modifications of the hybrid carrageenans present in the seaweed can be responsible of this unexpected thermal trend. Experimental drying data were modelled using two-parameter Page model (n, k). Page parameter n was constant (1.31 ± 0.10) at tested temperatures, but k varied significantly with drying temperature (from 18.5 ± 0.2 10-3 min-n at 35 °C up to 28.4 ± 0.8 10-3 min-n at 45 and 55 °C). Drying experiments allowed the determination of the critical moisture content of seaweed (0.87 ± 0.06 kg water (kg d.b.)-1). A diffusional model considering slab geometry was employed to determine the effective diffusion coefficient of water during the falling rate period at different temperatures.

  18. Effect of different air-drying time on the microleakage of single-step self-etch adhesives

    OpenAIRE

    Moosavi, Horieh; Forghani, Maryam; Managhebi, Esmatsadat

    2013-01-01

    Objectives This study evaluated the effect of three different air-drying times on microleakage of three self-etch adhesive systems. Materials and Methods Class I cavities were prepared for 108 extracted sound human premolars. The teeth were divided into three main groups based on three different adhesives: Opti Bond All in One (OBAO), Clearfil S3 Bond (CSB), Bond Force (BF). Each main group divided into three subgroups regarding the air-drying time: without application of air stream...

  19. Soil emissions of nitric oxide in a seasonally dry tropical forest of Mexico

    Science.gov (United States)

    Davidson, Eric A.; Vitousek, Peter M.; Riley, Ralph; Matson, Pamela A.; Garcia-Mendez, Georgina; Maass, J. M.

    1991-01-01

    Soil emissions of NO were measured at the Chamela Biological Station, Mexico, using soil covers and a field apparatus of NO detection based on CrO3 conversion of NO to NO2 and detection of NO2 by chemiluminescence with Luminol. Mean NO fluxes from forest soils ranged from 0.14 to 0.52 ng NO-N/sq cm/hr during the dry season and from 0.73 to 1.27 ng NO-N/sq cm/hr during the wet season. A fertilized floodplain pasture exhibited higher fluxes, but an unfertilized upland pasture, which represents the fastest growing land use in the region, had flux rates similar to the forest sites. Wetting experiments at the end of the dry season caused large pulses of NO flux, equaling 10 percent to 20 percent of the estimated annual NO emissions of 0.5-1.0 kg N/ha from the forest sites. Absence of a forest canopy during the dry season and the first wet season rain probably results in substantial NO(x) export from the forest system that may be important to regional atmospheric chemical processes. Wetting experiments during the wet season and a natural rain event had little or no stimulatory effect on NO flux rates.

  20. Effect of drying-wetting cycles on leaching behavior of cement solidified lead-contaminated soil.

    Science.gov (United States)

    Li, Jiang-Shan; Xue, Qiang; Wang, Ping; Li, Zhen-Ze; Liu, Lei

    2014-12-01

    Lead contaminated soil was treated by different concentration of ordinary Portland cement (OPC). Solidified cylindrical samples were dried at 40°C in oven for 48 h subsequent to 24h of immersing in different solution for one drying-wetting. 10 cycles were conducted on specimens. The changes in mass loss of specimens, as well as leaching concentration and pH of filtered leachates were studied after each cycle. Results indicated that drying-wetting cycles could accelerate the leaching and deterioration of solidified specimens. The cumulative leached lead with acetic acid (pH=2.88) in this study was 109, 83 and 71 mg respectively for solidified specimens of cement-to-dry soil (C/Sd) ratios 0.2, 0.3 and 0.4, compared to 37, 30, and 25mg for a semi-dynamic leaching test. With the increase of cycle times, the cumulative mass loss of specimens increased linearly, but pH of filtered leachates decreased. The leachability and deterioration of solidified specimens increased with acidity of solution. Increases of C/Sd clearly reduced the leachability and deterioration behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. PCB in soils and estimated soil-air exchange fluxes of selected PCB congeners in the south of Sweden

    International Nuclear Information System (INIS)

    Backe, Cecilia; Cousins, Ian T.; Larsson, Per

    2004-01-01

    PCB concentrations were studied in different soils to determine the spatial variation over a region of approximately 11 000 km 2 . PCB congener pattern was used to illustrate the spatial differences, as shown by principal component analysis (PCA). The relationship to different soil parameters was studied. PCB concentrations in soil showed a large variation between sampling-areas with median concentrations ranging between 2.3 and 332 ng g -1 (dw). Highest concentrations were found at two sites with sandy soils, one with extremely high organic carbon content. Both sites were located on the west coast of southern Sweden. Soils with similar soil textures (i.e. sandy silt moraine) did not show any significant differences in PCB concentrations. PCB congener composition was shown to differ between sites, with congener patterns almost site-specific. PCB in air and precipitation was measured and the transfer of chemicals between the soil and air compartments was estimated. Soil-air fugacity quotient calculations showed that the PCBs in the soil consistently had a higher fugacity than the PCBs in the air, with a median quotient value of 2.7. The gaseous fluxes between soil and air were estimated using standard modelling equations and a net soil-air flux estimated by subtracting bulk deposition from gaseous soil-air fluxes. It was shown that inclusion of vertical sorbed phase transport of PCBs in the soil had a large effect on the direction of the net soil-air exchange fluxes. - Soil-air exchange of PCBs is investigated and modelled across Sweden

  2. Defining a procedure for predicting the duration of the approximately isothermal segments within the proposed drying regime as a function of the drying air parameters

    Science.gov (United States)

    Vasić, M.; Radojević, Z.

    2017-08-01

    One of the main disadvantages of the recently reported method, for setting up the drying regime based on the theory of moisture migration during drying, lies in a fact that it is based on a large number of isothermal experiments. In addition each isothermal experiment requires the use of different drying air parameters. The main goal of this paper was to find a way how to reduce the number of isothermal experiments without affecting the quality of the previously proposed calculation method. The first task was to define the lower and upper inputs as well as the output of the “black box” which will be used in the Box-Wilkinson’s orthogonal multi-factorial experimental design. Three inputs (drying air temperature, humidity and velocity) were used within the experimental design. The output parameter of the model represents the time interval between any two chosen characteristic points presented on the Deff - t. The second task was to calculate the output parameter for each planed experiments. The final output of the model is the equation which can predict the time interval between any two chosen characteristic points as a function of the drying air parameters. This equation is valid for any value of the drying air parameters which are within the defined area designated with lower and upper limiting values.

  3. Behavior of two phenyl urea herbicides in clayey soils and effect of alternating dry-wet conditions on their availability.

    Science.gov (United States)

    Haouari, Jamila; Dahchour, Abdelmalek; Peña-Heras, Arancha; Louchard, Xzavier; Lennartz, Berndt; Alaoui, Mohamed Elbelghiti; Satrallah, Ahmad

    2006-01-01

    Adsorption and mobility of linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) and diuron (3-(3,4-dichlorophenyl)-1, 1-dimethylurea) were studied in clayey soils from the Gharb area (Morocco). Soils A and B were planted with sun flower (Helianthus annuus) while soil C was planted with sugar cane (Saccharum offcinarum). Adsorption was studied for linuron in soils A and B, while mobility was studied only in soil B. Adsorption data were found to fit the Freundlich equation with correlation coefficients r2 > 0.9. Freundlich coefficients (Kf, nf) were in agreement with L and S isotherm types for soils A and B, respectively. Values of Koc (195 and 102) indicate moderate adsorption. Desorption isotherms for linuron showed hysteresis for both soils. The pesticide would be more bound to soil A (H = 8.44) than to soil B (H = 4.01). The effect of alternating wet and dry conditions was tested for soils A and B. Results showed that retention would increase in soil subject to an additional wet and dry cycle. In the case of diuron isotherm was of type L in soil C. Desorption was noticeable at high concentrations and tended to decrease when concentrations diminished. Mobility of linuron was tested in polyvinyle chloride (PVC) columns, which received different treatments before their percolation. The pesticide was more mobile in a previously saturated column. In columns subject to a drying step after saturation with water, linuron mobility was greatly reduced.

  4. Electro-Hydrodynamics and Kinetic Modeling of Dry and Humid Air Flows Activated by Corona Discharges

    Science.gov (United States)

    P. Sarrette, J.; Eichwald, O.; Marchal, F.; Ducasse, O.; Yousfi, M.

    2016-05-01

    The present work is devoted to the 2D simulation of a point-to-plane Atmospheric Corona Discharge Reactor (ACDR) powered by a DC high voltage supply. The corona reactor is periodically crossed by thin mono filamentary streamers with a natural repetition frequency of some tens of kHz. The study compares the results obtained in dry air and in air mixed with a small amount of water vapour (humid air). The simulation involves the electro-dynamics, chemical kinetics and neutral gas hydrodynamics phenomena that influence the kinetics of the chemical species transformation. Each discharge lasts about one hundred of a nanosecond while the post-discharge occurring between two successive discharges lasts one hundred of a microsecond. The ACDR is crossed by a lateral dry or humid air flow initially polluted with 400 ppm of NO. After 5 ms, the time corresponding to the occurrence of 50 successive discharge/post-discharge phases, a higher NO removal rate and a lower ozone production rate are found in humid air. This change is due to the presence of the HO2 species formed from the H primary radical in the discharge zone.

  5. Properties of metallocene complexes during the oxidative crosslinking of air drying coatings

    Science.gov (United States)

    Stava, Vit; Erben, Milan; Vesely, David; Kalenda, Petr

    2007-05-01

    Driers are added to air drying paints to accelerate the hardening of spread coating. For decades cobalt octoate has been the most widely used drier because of its good performance at ambient temperature. Recently, several reports describing possible carcinogenity and genotoxicity of cobalt and cobalt salts, such as cobalt sulfate in aerosols, have appeared. It is necessary to reduce the amount of cobalt compounds in coatings industry. Present study deals with the possibility of using ferrocene and its derivatives as driers for air drying coatings. We concentrated particularly on the synergic effect between these metallocene complexes and the cobalt drier. In the first step the kinetics of autooxidation by FTIR spectroscopy in model systems was investigated. Then the metallocene complexes were applied together with cobalt drier to alkyd resin, where their influence on hardness of spread coatings was examined.

  6. Modelling Water Flow through Paddy Soils under Alternate Wetting and Drying Irrigation Practice

    Science.gov (United States)

    Shekhar, S.; Mailapalli, D. R.; Das, B. S.; Raghuwanshi, N. S.

    2017-12-01

    Alternate wetting and drying (AWD) irrigation practice in paddy cultivation requires an optimum soil moisture stress (OSMS) level at which irrigation water savings can be maximized without compromising the yield reduction. Determining OSMS experimentally is challenging and only possible with appropriate modeling tools. In this study, field experiments on paddy were conducted in thirty non-weighing type lysimeters during dry seasons of 2016 and 2017. Ten plots were irrigated using continuous flooding (CF) and the rest were irrigated with AWD practice at 40mb and 75mb soil moisture stress levels. Depth of ponding and soil suction at 10, 40 and 70 cm from the soil surface were measured daily from all lysimeter plots. The measured field data were used in calibration and validation of Hydrus-1D model and simulated the water flow for both AWD and CF plots. The Hydrus-1D is being used to estimate OSMS for AWD practice and compared the seasonal irrigation water input and deep percolation losses with CF practice.

  7. Ozone Generation in Dry Air Using Pulsed Discharges With and Without a Solid Dielectric Layer

    OpenAIRE

    Samaranayake, W.J.M.; Miyahara, Y.; Namihira, T.; Katsuki, S.; Hackam, R.; Akiyama, H.; ミヤハラ, Y.; ナミヒラ, タカオ; カツキ, スナオ; アキヤマ, ヒデノリ; 浪平, 隆男; 勝木, 淳; 秋山, 秀典

    2001-01-01

    Energy efficient generation of ozone is very important because ozone is being used increasingly in a wide range of industrial applications. Ozonizers usually use dielectric barrier discharges and employ alternating current (ac) with consequent heat generation, which necessitates cooling. In the present study, very short duration pulsed voltage is employed resulting in reduced heating of the gas and discharge reactor. A comparison of ozone generation in dry air using a coaxial concentric elect...

  8. Understanding spatial heterogeneity in soil carbon and nitrogen cycling in regenerating tropical dry forests

    Science.gov (United States)

    Waring, B. G.; Powers, J. S.; Branco, S.; Adams, R.; Schilling, E.

    2015-12-01

    Tropical dry forests (TDFs) currently store significant amounts of carbon in their biomass and soils, but these highly seasonal ecosystems may be uniquely sensitive to altered climates. The ability to quantitatively predict C cycling in TDFs under global change is constrained by tremendous spatial heterogeneity in soil parent material, land-use history, and plant community composition. To explore this variation, we examined soil carbon and nitrogen dynamics in 18 permanent plots spanning orthogonal gradients of stand age and soil fertility. Soil C and N pools, microbial biomass, and microbial extracellular enzyme activities were most variable at small (m2) spatial scales. However, the ratio of organic vs. inorganic N cycling was consistently higher in forest stands dominated by slow-growing, evergreen trees that associate with ectomycorrhizal fungi. Similarly, although bulk litter stocks and turnover rates varied greatly among plots, litter decomposition tended to be slower in ectomycorrhizae-dominated stands. Soil N cycling tended to be more conservative in older plots, although the relationship between stand age and element cycling was weak. Our results emphasize that microscale processes, particularly interactions between mycorrhizal fungi and free-living decomposers, are important controls on ecosystem-scale element cycling.

  9. Influence of drying air parameters on mass transfer characteristics of apple slices

    Science.gov (United States)

    Beigi, Mohsen

    2016-10-01

    To efficiently design both new drying process and equipment and/or to improve the existing systems, accurate values of mass transfer characteristics are necessary. The present study aimed to investigate the influence of drying air parameters (i.e. temperature, velocity and relative humidity) on effective diffusivity and convective mass transfer coefficient of apple slices. The Dincer and Dost model was used to determine the mass transfer characteristics. The obtained Biot number indicated that the moisture transfer in the apple slices was controlled by both internal and external resistance. The effective diffusivity and mass transfer coefficient values obtained to be in the ranges of 7.13 × 10-11-7.66 × 10-10 and 1.46 × 10-7-3.39 × 10-7 m s-1, respectively and the both of them increased with increasing drying air temperature and velocity, and decreasing relative humidity. The validation of the model showed that the model predicted the experimental drying curves of the samples with a good accuracy.

  10. Radon as a tracer for soil-gas entry into a house located next to a contaminated dry-cleaning property

    International Nuclear Information System (INIS)

    Andersen, C.E.

    2001-07-01

    This study applies the naturally occurring radioactive gas radon-222 as a tracer for soil-gas entry into a house located next to a dry-cleaners shop. This is possible because the concentration of radon in the soil below the house is about 1000 times higher than the concentration in outdoor air. The study is based on continuous indoor measurement of radon, differential pressures, barometric pressure and temperatures and grab samples of radon below the slab and in the soil in the vicinity of the house. During the investigation, vacuum extraction were used to remove chlorinated solvents (perchloroethylene, PCE) from the unsaturated zone. The study shows that the vacuum extraction influences the radon concentration in and below the house. When the vacuum pump is on, the indoor radon concentration is only 10 Bq/m 3 corresponding to the contribution from radon in outdoor air and exhalation from building materials. When the vacuum pump is set off, the average indoor radon concentration increases to 30 Bq/m 3 . It is believed that the increase is caused by radon entry from the soil. Regression analysis demonstrates that changes in the indoor radon concentration can be explained by changes in indoor-outdoor pressure differences and changes in the atmospheric pressure. This suggests that advection is the primary mode of entry. Under some highly simplifying assumptions the soil-gas entry is found to be around 1 m 3 /h. This, however, is most likely an overestimate. Based on the measured radon concentration in the exhaust air from the vacuum system and a typical radon emanation rate for Danish soil, it is estimated that the soil vapor extraction system ventilates about 10000 m 3 of soil. The investigation is supported by numerical model calculations with the finite-volume model Rnmod3d. (au)

  11. Predicting Soil-Air and Soil-Water Transport Properties During Soil Vapor Extraction

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe

    Increased application of in-situ technology for control and removal of volatile organic compounds (VOC) in the subsurface has made the understanding of soil physical properties and their impact upon contaminant transport even more important. Knowledge of contaminant transport is important when...... properties of undisturbed soil from more easily measurable soil properties are developed. The importance of soil properties with respect to contaminant migration during remediation by soil vapor extraction (SVE) in the unsaturated zone was investigated using numerical simulations....

  12. Effect of moisture content and dry unit weight on the resilient modulus of subgrade soils predicted by cone penetration test.

    Science.gov (United States)

    2002-06-01

    The objective of this study was to investigate the effect of moisture content and dry unit weight on the resilient characteristics of subgrade soil predicted by the cone penetration test. An experimental program was conducted in which cone penetratio...

  13. The effects of climate changes on soil methane oxidation in a dry Arctic tundra

    Science.gov (United States)

    D'Imperio, Ludovica

    2014-05-01

    The effects of climate changes on soil methane oxidation in a dry Arctic tundra. Ludovica D'Imperio1, Anders Michelsen1, Christian J. Jørgensen1, Bo Elberling1 1Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark At Northern latitudes climatic changes are predicted to be most pronounced resulting in increasing active layer depth and changes in growing season length, vegetation cover and nutrient cycling. As a consequence of increased temperature, large stocks of carbon stored in the permafrost-affected soils could become available for microbial transformations and under anoxic conditions result in increasing methane production affecting net methane (CH4) budget. Arctic tundra soils also serves as an important sink of atmospheric CH4 by microbial oxidation under aerobic conditions. While several process studies have documented the mechanisms behind both production and emissions of CH4 in arctic ecosystems, an important knowledge gap exists with respect to the in situ dynamics of microbial-driven uptake of CH4 in arctic dry lands which may be enhanced as a consequence of global warming and thereby counterbalancing CH4 emissions from Arctic wetlands. In-situ methane measurements were made in a dry Arctic tundra in Disko Island, Western Greenland, during the summer 2013 to assess the role of seasonal and inter-annual variations in temperatures and snow cover. The experimental set-up included snow fences installed in 2012, allowed investigations of the emissions of GHGs from soil under increased winter snow deposition and ambient field conditions. The soil fluxes of CH4 and CO2 were measured using closed chambers in manipulated plots with increased summer temperatures and shrub removal with or without increased winter precipitation. At the control plots, the averaged seasonal CH4 oxidation rates ranged between -0.05 mg CH4 m-2 hr-1 (end of August) and -0.32 mg CH4 m-2 hr-1 (end of June). In the

  14. Drying/rewetting cycles of the soil under alternate partial root-zone drying irrigation reduce carbon and nitrogen retention in the soil-plant systems of potato

    DEFF Research Database (Denmark)

    Sun, Yanqi; Yan, Fei; Liu, Fulai

    2013-01-01

    for five weeks. For each N rate, the PRD and DI plants received a same amount of water, which allowed re-filling one half of the PRD pots close to full water holding capacity. The results showed that plant dry biomass, plant water use, and water use efficiency were increased with increasing N...... retention in the soil–plant systems of potato. Potato plants were grown in 20 L split-root pots with three N-fertilization rates, viz., 1.4 (N1), 2.5 (N2), and 4 (N3) g N pot−1 soil, respectively. At tuber initiation and earlier tuber bulking stages, the plants were subjected to PRD and DI treatment...

  15. In situ air sparging for bioremediation of groundwater and soils

    International Nuclear Information System (INIS)

    Lord, D.; Lei, J.; Chapdelaine, M.C.; Sansregret, J.L.; Cyr, B.

    1995-01-01

    Activities at a former petroleum products depot resulted in the hydrocarbon contamination of soil and groundwater over a 30,000-m 2 area. Site remediation activities consisted of three phases: site-specific characterization and treatability study, pilot-scale testing, and full-scale bioremediation. During Phase 1, a series of site/soil/waste characterizations was undertaken to ascertain the degree of site contamination and to determine soil physical/chemical and microbiological characteristics. Treatability studies were carried out to simulate an air sparging process in laboratory-scale columns. Results indicated 42% mineral oil and grease removal and 94% benzene, toluene, ethylbenzene, and xylenes (BTEX) removal over an 8-week period. The removal rate was higher in the unsaturated zone than in the saturated zone. Phase 2 involved pilot-scale testing over a 550-m 2 area. The radius of influence of the air sparge points was evaluated through measurements of dissolved oxygen concentrations in the groundwater and of groundwater mounding. A full-scale air sparging system (Phase 3) was installed on site and has been operational since early 1994. Physical/chemical and microbiological parameters, and contaminants were analyzed to evaluate the system performance

  16. Experimental investigation on influence of porous material properties on drying process by a hot air jet

    International Nuclear Information System (INIS)

    Di Marco, P; Filippeschi, S

    2012-01-01

    The drying process of porous media is a subject of scientific interest, and different mathematical approaches can be found in the literature. A previous paper by the same authors showed that the celebrated Martin correlation for hot air jet heat and mass transfer yields different degrees of accuracy (from 15% to 65%, increasing at high values of input power) if tested on different fabrics, the remaining conditions being the same. In this paper the fabric drying has been experimentally investigated more in depth. A dedicated experimental apparatus for hot jet drying was assembled and operated, in which a hot jet impinges perpendicularly onto a wet fabric. A calibrated orifice was adopted to measure the jet flow rate, with an accuracy better than 3%. The drying power was determined by continuously weighing with a precision scale a moistened patch exposed to the drying jet. The effect of the time of the exposure and the initial amount of water has been evaluated for each sample. During the hot jet exposure, the temperature distribution over the wet patch has been observed by an infrared thermo-camera. A mathematical model of water transport inside and outside the fabric was developed, in order to evidence the governing transport resistances. The theoretical predictions have been compared with the experimental results, and showed the necessity to modify correlations and models accounting for fabric properties.

  17. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    Science.gov (United States)

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  18. [Research on characteristics of soil clay mineral evolution in paddy field and dry land by XRD spectrum].

    Science.gov (United States)

    Zhang, Zhi-dan; Li, Qiao; Luo, Xiang-li; Jiang, Hai-chao; Zheng, Qing-fu; Zhao, Lan-po; Wang, Ji-hong

    2014-08-01

    The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture-->vermiculite, while in paddy field it was S/I mixture-->vermiculite-->kaolinite. One kind of hydroxylated 'chlorite' mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two'kinds of land use comparatively, and was a new perspective of soil minerals study.

  19. Roles of Arbuscular Mycorrhizal Fungi and Soil Abiotic Conditions in the Establishment of a Dry Grassland Community.

    Directory of Open Access Journals (Sweden)

    Jana Knappová

    Full Text Available The importance of soil biota in the composition of mature plant communities is commonly acknowledged. In contrast, the role of soil biota in the early establishment of new plant communities and their relative importance for soil abiotic conditions are still poorly understood.The aim of this study was to understand the effects of soil origin and soil fungal communities on the composition of a newly established dry grassland plant community. We used soil from two different origins (dry grassland and abandoned field with different pH and nutrient and mineral content. Grassland microcosms were established by sowing seeds of 54 species of dry grassland plants into the studied soils. To suppress soil fungi, half of the pots were regularly treated with fungicide. In this way, we studied the independent and combined effects of soil origin and soil community on the establishment of dry grassland communities.The effect of suppressing the soil fungal community on the richness and composition of the plant communities was much stronger than the effect of soil origin. Contrary to our expectations, the effects of these two factors were largely additive, indicating the same degree of importance of soil fungal communities in the establishment of species-rich plant communities in the soils from both origins. The negative effect of suppressing soil fungi on species richness, however, occurred later in the soil from the abandoned field than in the soil from the grassland. This result likely occurred because the negative effects of the suppression of fungi in the field soil were caused mainly by changes in plant community composition and increased competition. In contrast, in the grassland soil, the absence of soil fungi was limiting for plants already at the early stages of their establishment, i.e., in the phases of germination and early recruitment. While fungicide affects not only arbuscular mycorrhizal fungi but also other biota, our data indicate that changes

  20. Simultaneous application of microwave energy and hot air to whole drying process of apple slices: drying kinetics, modeling, temperature profile and energy aspect

    Science.gov (United States)

    Horuz, Erhan; Bozkurt, Hüseyin; Karataş, Haluk; Maskan, Medeni

    2018-02-01

    Drying kinetics, modeling, temperature profile and energy indices were investigated in apple slices during drying by a specially designed microwave-hot air domestic hybrid oven at the following conditions: 120, 150 and 180 W microwave powers coupled with 50, 60 and 70 °C air temperatures. Both sources of energy were applied simultaneously during the whole drying processes. The drying process continued until the moisture content of apple slices reached to 20% from 86.3% (wet basis, w.b). Drying times ranged from 330 to 800 min and decreased with increasing microwave power and air temperatures. The constant rate period was only observed at low microwave powers and air temperatures. Two falling rate periods were observed. Temperature of apple slices sharply increased within the first 60 min, then reached equilibrium with drying medium and finally increased at the end of the drying process. In order to describe drying behavior of apple slices nine empirical models were applied. The Modified Logistic Model fitted the best our experimental data ( R 2 = 0.9955-0.9998; χ 2 = 3.46 × 10-5-7.85 × 10-4 and RMSE = 0.0052-0.0221). The effective moisture and thermal diffusivities were calculated by Fick's second law and ranged from 1.42 × 10-9 to 3.31 × 10-9 m2/s and 7.70 × 10-9 to 12.54 × 10-9 m2/s, respectively. The activation energy ( Ea) values were calculated from effective moisture diffusivity ( Deff), thermal diffusivity ( α) and the rate constant of the best model ( k). The Ea values found from these three terms were similar and varied from 13.04 to 33.52 kJ/mol. Energy consumption and specific energy requirement of the hybrid drying of apple slices decreased and energy efficiency of the drying system increased with increasing microwave power and air temperature. Apples can be dried rapidly and effectively by use of the hybrid technique.

  1. Effect of air-drying time of single-application self-etch adhesives on dentin bond strength.

    Science.gov (United States)

    Chiba, Yasushi; Yamaguchi, Kanako; Miyazaki, Masashi; Tsubota, Keishi; Takamizawa, Toshiki; Moore, B Keith

    2006-01-01

    This study examined the effect of air-drying time of adhesives on the dentin bond strength of several single-application self-etch adhesive systems. The adhesive/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), Clearfil Tri-S Bond/Clearfil AP-X (CT), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Gradia Direct (GB) and One-Up Bond F Plus/Palfique Estelite (OF). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied according to each manufacturer's instructions followed by air-drying time for 0 (without air-drying), 5 and 10 seconds. After light irradiation of the adhesives, the resin composites were condensed into a mold (phi4x2 mm) and polymerized. Ten samples per test group were stored in 37 degrees C distilled water for 24 hours; they were then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD tests (alpha = 0.05) were done. FE-SEM observations of the resin/dentin interface were also conducted. Dentin bond strength varied with the different air drying times and ranged from 5.8 +/- 2.4 to 13.9 +/- 2.8 MPa for AP, 4.9 +/- 1.5 to 17.1 +/- 2.3 MPa for CT, 7.9 +/- 2.8 to 13.8 +/- 2.4 MPa for FB, 3.7 +/- 1.4 to 13.4 +/- 1.2 MPa for GB and 4.6 +/- 2.1 to 13.7 +/- 2.6 MPa for OF. With longer air drying of adhesives, no significant changes in bond strengths were found for the systems used except for OF. Significantly lower bond strengths were obtained for the 10-second air-drying group for OF. From FE-SEM observations, gaps between the cured adhesive and resin composites were observed for the specimens without the air drying of adhesives except for OF. The data suggests that, with four of the single-application self-etch adhesive systems, air drying is essential to obtain adequate dentin bond strengths, but increased drying time does not significantly influence bond strength. For the other system studied, the bond strength

  2. Dried gamma-irradiated sewage solids use on calcareous soils: crop yields and heavy metals uptake

    International Nuclear Information System (INIS)

    McCaslin, B.D.; Sivinski, J.S.

    1980-01-01

    The fertilizer values of gamma-irradiated digested sewage solids (RDSS) and gamma-irradiated undigested sewage solids (RUSS) have been examined on calcareous soils. Previously published data from Sandia Laboratories have shown that approximately 1 mega-rad of gamma-irradiation effectively destroys pathogenic bacteria, parasites and plant seeds in dried sewage solids. Greenhouse experiments directly comparing gamma-irradiated and non-irradiated undigested and digested dried sewage solids as fertilizers indicate little or no effect of 1 mega-rad gamma radiation treatment on plant yield or plant-nutrient uptake and demonstrated considerable benefit from using sewage solids on calcareous soils. Plant response to undigested sewage solids was considerably greater than to digested sewage solids when applied at levels that were isonitrogenous. The calcareous soils in New Mexico typically range in pH from 7.5 to 9.0, limiting the plant-availability of many elements, especially heavy metals. Soils irrigated with sewage-effluent for 40 years demonstrated beneficial use of supplied plant-nutrients with no apparent increase in plant-uptake of heavy metals. RDSS applied to a calcareous soil low in plant-available iron increased plant growth in the greenhouse considerably more than treatments with equal amounts of nitrogen, phosphorus and iron applied as common fertilizer materials. Plant tissue concentrations of Fe, Zn, Mn and Cu showed that RDSS was a good source of these nutrients. Results also indicated that the total soluble salt concentration of the RDSS was the factor most limiting plant growth. Chromium, Cd, Ni and Pd plant-tissue concentrations were apparently not increased by RDSS treatments. (Auth.)

  3. Forest structure, diversity and soil properties in a dry tropical forest in Rajasthan, Western India

    Directory of Open Access Journals (Sweden)

    J. I. Nirmal Kumar

    2011-06-01

    Full Text Available Structure, species composition, and soil properties of a dry tropical forest in Rajasthan Western India, were examined by establishment of 25 plots. The forest was characterized by a relatively low canopy and a large number of small-diameter trees. Mean canopy height for this forest was 10 m and stands contained an average of 995 stems ha-1 (= 3.0 cm DBH; 52% of those stems were smaller than 10 cm DBH. The total basal area was 46.35 m2ha-1, of which Tectona grandis L. contributed 48%. The forest showed high species diversity of trees. 50 tree species (= 3.0 cm DBH from 29 families were identified in the 25 sampling plots. T. grandis (20.81% and Butea monosperma (9% were the dominant and subdominant species in terms of importance value. The mean tree species diversity indices for the plots were 1.08 for Shannon diversity index (H´, 0.71 for equitability index (J´ and 5.57 for species richness index (S´, all of which strongly declined with the increase of importance value of the dominant, T. grandis. Measures of soil nutrients indicated low fertility, extreme heterogeneity. Regression analysis showed that stem density and the dominant tree height were significantly correlated with soil pH. There was a significant positive relationship between species diversity index and soil available P, exchangeable K+, Ca2+ (all p values < 0.001 and a negative relationship with N, C, C:N and C:P ratio. The results suggest that soil properties are major factors influencing forest composition and structure within the dry tropical forest in Rajasthan.

  4. The Effects of Organic Manures, Soil Cover and Drying Temperature on Some Growth and Phytochemical Characteristics of Calendula officinalis

    Directory of Open Access Journals (Sweden)

    Lamia Vojodi Mehrabani

    2017-01-01

    Full Text Available Two separate experiments were conducted to evaluate the effects of some pre and post -harvest treatments on growth characteristics of Calendula officinalis. The first experiment as RCBD with three replication studied the effects of organic fertilizers as vermicompost, cow and poultry manure with control plus soil cover (plastic white and black. Organic manure application +mulch had positive effects on flower fresh weight. The greatest amount for chlorophyll b content was recorded in vermicompost + black plastic cover. In the second experiment, the effects of nutrition with organic manure +soil cover and post-harvest flower drying temperature (natural drying in shade condition and oven drying at 40 and 60 0C as a factorial based on RCBD were evaluated. The highest methanolic extract amount and total anthocyanin content were recorded with vermicompost + black cover + natural drying. For essential oil content and carotenoids gross amount poultry manure + black cover and drying at 60 0C was the preferred treatments. The highest recorded data for total flavonoids was traced in vermicompot and cow manure with white cover at natural drying condition. For total phenolics content, cow manure + black cover at 40 0C used for drying was selected as the treatment of choice. Also, vermicompost+ black mulch and natural drying were nice treatment combinations for the highest total phenolics content. In total, all the treatment applied i.e. organic manures, soil covers and drying methods at varying levels and combinations had suitable effectiveness on the growth characteristics and phytochemicals content of Calendula officinalis.

  5. In situ determination of soil carbon pool by inelastic neutron scattering: Comparison with dry combustion

    International Nuclear Information System (INIS)

    Wielopolski, L.; Mitra, S.; Chatterjee, A.; Lal, R.

    2011-01-01

    There is a well-documented need for new in situ technologies for elemental analysis of soil, particularly for carbon (C), that overcome the limitations of the currently established chemical method by dry combustion (DC). In this work, we evaluated the concordance between the new INS (inelastic neutron scattering) technology and the DC method. The comparisons were carried out in the high C content (30-40%) organic soils of Willard, Ohio (4 sites), in natural forest in Willard, Ohio (1 site), and in a watershed pasture, with an ∼ 10 o slope, in Coshocton, Ohio (5 sites). In addition to these stationary measurements, the organic soil and the pasture were continuously scanned with the inelastic neutron scattering (INS) system to obtain the transects mean C value. Both types of measurements, INS and DC, registered a decline in the surface density of C along transects in the watershed and in the organic soil. Similarly, both recorded a drop in C in the organic soil of about 0.16%. In the pastureland, declines in C levels of 0.08% and 0.10% were observed, respectively, by DC and INS. Combining the results from the three sites yielded a very satisfactory correlation between the INS- and DC-responses, with a regression coefficient, r 2 , value of about 0.99. This suggests the possibility of establishing a universal regression line for various soil types. In addition, we demonstrated the ability of INS to measure the mean value over transect. In organic soil the mean value of an INS scan agreed, ∼ 0.5%, with the mean values of the DC analysis, whereas large discrepancy between these two was recorded in the pastureland. Overall, the various trends observed in C measurements by INS concurred with those determined by the DC method, so enhancing the confidence in the new INS technology.

  6. Microbial diversity of a Mediterranean soil and its changes after biotransformed dry olive residue amendment.

    Directory of Open Access Journals (Sweden)

    José A Siles

    Full Text Available The Mediterranean basin has been identified as a biodiversity hotspot, about whose soil microbial diversity little is known. Intensive land use and aggressive management practices are degrading the soil, with a consequent loss of fertility. The use of organic amendments such as dry olive residue (DOR, a waste produced by a two-phase olive-oil extraction system, has been proposed as an effective way to improve soil properties. However, before its application to soil, DOR needs a pre-treatment, such as by a ligninolytic fungal transformation, e.g. Coriolopsis floccosa. The present study aimed to describe the bacterial and fungal diversity in a Mediterranean soil and to assess the impact of raw DOR (DOR and C. floccosa-transformed DOR (CORDOR on function and phylogeny of soil microbial communities after 0, 30 and 60 days. Pyrosequencing of the 16S rRNA gene demonstrated that bacterial diversity was dominated by the phyla Proteobacteria, Acidobacteria, and Actinobacteria, while 28S-rRNA gene data revealed that Ascomycota and Basidiomycota accounted for the majority of phyla in the fungal community. A Biolog EcoPlate experiment showed that DOR and CORDOR amendments decreased functional diversity and altered microbial functional structures. These changes in soil functionality occurred in parallel with those in phylogenetic bacterial and fungal community structures. Some bacterial and fungal groups increased while others decreased depending on the relative abundance of beneficial and toxic substances incorporated with each amendment. In general, DOR was observed to be more disruptive than CORDOR.

  7. Nitrogen dynamics in the soil-plant system under deficit and partial root-zone drying irrigation strategies in potatoes

    DEFF Research Database (Denmark)

    Shahnazari, Ali; Ahmadi, Seyed Hamid; Lærke, Poul Erik

    2008-01-01

    Experiments were conducted in lysimeters with sandy soil under an automatic rain-out shelter to study the effects of subsurface drip irrigation treatments, full irrigation (FI), deficit irrigation (DI) and partial root-zone drying (PRD), on nitrogen (N) dynamics in the soil-plant system of potatoes...

  8. Comparison of heat transfer and soil impacts of air curtain burner burning and slash pile burning

    Science.gov (United States)

    Woongsoon Jang; Deborah S. Page-Dumroese; Han-Sup Han

    2017-01-01

    We measured soil heating and subsequent changes in soil properties between two forest residue disposal methods: slash pile burning (SPB) and air curtain burner (ACB). The ACB consumes fuels more efficiently and safely via blowing air into a burning container. Five burning trials with different fuel sizes were implemented in northern California, USA. Soil temperature...

  9. Competition between trees and grasses for both soil water and mineral nitrogen in dry savannas.

    Science.gov (United States)

    Donzelli, D; De Michele, C; Scholes, R J

    2013-09-07

    The co-existence of trees and grasses in savannas in general can be the result of processes involving competition for resources (e.g. water and nutrients) or differential response to disturbances such as fire, animals and human activities; or a combination of both broad mechanisms. In moist savannas, the tree-grass coexistence is mainly attributed to of disturbances, while in dry savannas, limiting resources are considered the principal mechanism of co-existence. Virtually all theoretical explorations of tree-grass dynamics in dry savannas consider only competition for soil water. Here we investigate whether coexistence could result from a balanced competition for two resources, namely soil water and mineral nitrogen. We introduce a simple dynamical resource-competition model for trees and grasses. We consider two alternative hypotheses: (1) trees are the superior competitors for nitrogen while grasses are superior competitors for water, and (2) vice-versa. We study the model properties under the two hypotheses and test each hypothesis against data from 132 dry savannas in Africa using Kendall's test of independence. We find that Hypothesis 1 gets much more support than Hypothesis 2, and more support than the null hypothesis that neither is operative. We further consider gradients of rainfall and nitrogen availability and find that the Hypothesis 1 model reproduces the observed patterns in nature. We do not consider our results to definitively show that tree-grass coexistence in dry savannas is due to balanced competition for water and nitrogen, but show that this mechanism is a possibility, which cannot be a priori excluded and should thus be considered along with the more traditional explanations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Forest structure, diversity and soil properties in a dry tropical forest in Rajasthan, Western India

    OpenAIRE

    J. I. Nirmal Kumar,; Kanti Patel,; Rohit Bhoi Kumar

    2011-01-01

    Structure, species composition, and soil properties of a dry tropical forest in Rajasthan Western India, were examined by establishment of 25 plots. The forest was characterized by a relatively low canopy and a large number of small-diameter trees. Mean canopy height for this forest was 10 m and stands contained an average of 995 stems ha-1 (≥ 3.0 cm DBH); 52% of those stems were smaller than 10 cm DBH. The total basal area was 46.35 m2ha-1, of which Tectona grandis L. contributed 48%. The fo...

  11. 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).

  12. Occurrence of Cronobacter spp. in Dried Foods, Fresh Vegetables and Soil.

    Science.gov (United States)

    Ueda, Shigeko

    2017-01-01

     The present study surveyed the occurrence of Cronobacter spp. in dried foods including milk powder, spices and herbs and others, and fresh vegetables commercially available in markets, and ground soil materials for the agriculture. Cronobacter spp. were isolated from 15% of 33 spice and herb samples and 3% of 36 taste foods, and these were C. turicensis, C. malonaticus, C. sakazakii and C. dubliensis. Cronobacter spp. from fresh vegetables were detected in 12% of field vegetables and 13% of hydroponic vegetables. C. turicensis was prevalent in field vegetables, and C. malonaticus was in hydroponic ones. And, Cronobacter spp. in shredded vegetables were detected from 44% of 9 samples, and these were C. dubliensis, C. turicensis and C. sakazakii. Also, Cronobacter spp. in soil from rice field, vegetable field and sandpits were predominantly C. sakazakii and C. malonaticus.

  13. Occurrence and quantitative microbial risk assessment of Cryptosporidium and Giardia in soil and air samples

    Directory of Open Access Journals (Sweden)

    Ana Paola Balderrama-Carmona

    2014-09-01

    Conclusions: Soil and air inhalation and/or ingestion are important vehicles for these parasites. To our knowledge, the results obtained in the present study represent the first QMRAs for cryptosporidiosis and giardiasis due to soil and air inhalation/ingestion in Mexico. In addition, this is the first evidence of the microbial air quality around these parasites in rural zones.

  14. Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai

    2014-01-01

    Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... treatments. Six months after the last biochar application, intact and disturbed soil samples were collected for analyses. Soil water retention was measured from −1 kPa to −100 kPa using tension tables and ceramic plates and from −10 MPa to −480 MPa using a Vapor Sorption Analyzer. Soil specific area...

  15. Possible roles of vacuolar H+-ATPase and mitochondrial function in tolerance to air-drying stress revealed by genome-wide screening of Saccharomyces cerevisiae deletion strains.

    Science.gov (United States)

    Shima, Jun; Ando, Akira; Takagi, Hiroshi

    2008-03-01

    Yeasts used in bread making are exposed to air-drying stress during dried yeast production processes. To clarify the genes required for air-drying tolerance, we performed genome-wide screening using the complete deletion strain collection of diploid Saccharomyces cerevisiae. The screening identified 278 gene deletions responsible for air-drying sensitivity. These genes were classified based on their cellular function and on the localization of their gene products. The results showed that the genes required for air-drying tolerance were frequently involved in mitochondrial functions and in connection with vacuolar H(+)-ATPase, which plays a role in vacuolar acidification. To determine the role of vacuolar acidification in air-drying stress tolerance, we monitored intracellular pH. The results showed that intracellular acidification was induced during air-drying and that this acidification was amplified in a deletion mutant of the VMA2 gene encoding a component of vacuolar H(+)-ATPase, suggesting that vacuolar H(+)-ATPase helps maintain intracellular pH homeostasis, which is affected by air-drying stress. To determine the effects of air-drying stress on mitochondria, we analysed the mitochondrial membrane potential under air-drying stress conditions using MitoTracker. The results showed that mitochondria were extremely sensitive to air-drying stress, suggesting that a mitochondrial function is required for tolerance to air-drying stress. We also analysed the correlation between oxidative-stress sensitivity and air-drying-stress sensitivity. The results suggested that oxidative stress is a critical determinant of sensitivity to air-drying stress, although ROS-scavenging systems are not necessary for air-drying stress tolerance. (c) 2008 John Wiley & Sons, Ltd.

  16. Quantifying the Effect of Soil Water Repellency on Infiltration Parameters Using a Dry Sand

    Science.gov (United States)

    Shillito, R.; Berli, M.; Ghezzehei, T. A.; Kaminski, E.

    2017-12-01

    Water infiltration into less than perfectly wettable soils has usually been considered an exceptional case—in fact, it may be the rule. Infiltration into soils exhibiting some degree of water repellency has important implications in agricultural irrigation, post-fire runoff, golf course and landscape management, and spill and contaminant mitigation. Beginning from fundamental principles, we developed a physically-based model to quantify the effect of water repellency on infiltration parameters. Experimentally, we used a dry silica sand and treated it to achieve various known degrees of water repellency. The model was verified using data gathered from multiple upward infiltration (wicking) experiments using the treated sand. The model also allowed us to explore the effect of initial soil moisture conditions on infiltration into water-repellent soils, and the physical interpretation of the simple water drop penetration time test. These results provide a fundamental step in the physically-based understanding of how water infiltrates into a less than perfectly wettable porous media.

  17. Low temperature hot air drying of potato cubes subjected to osmotic dehydration and intermittent microwave: drying kinetics, energy consumption and product quality indexes

    Science.gov (United States)

    Dehghannya, Jalal; Bozorghi, Somayyeh; Heshmati, Maryam Khakbaz

    2018-04-01

    Hot-air drying is a slow energy-extensive process. Use of intermittent microwave (IM) in hot-air (HA) drying of food products is characterized with advantages including reduced process time, energy saving, and improved final quality. In this study, the effect of IM-HA drying following an osmotic dehydration (OD) pretreatment was analyzed on qualitative and quantitative properties of the output (i.e. effective moisture diffusion coefficient (Deff), shrinkage, bulk density, rehydration and energy consumption). Temperature and airflow velocity were fixed at 40°C and 1 m/s, respectively. The process variables included sucrose solution concentration at five levels (0 or control, 10, 30, 50 and 70 w/w%), microwave output power at four levels (0 or control, 360, 600 and 900 W), and pulse ratio at four levels (1, 2, 3 and 4). Use of osmotic dehydration in combination with IM-HA drying reduced the drying time by up to about 54%. Increasing the osmotic solution concentration to 30% and using higher pulse ratios increased the Deff. The lowest shrinkage and bulk density as well as the highest rehydration belonged to the 900 W microwave power and pulse ratio of 4. The lowest energy consumption was observed when using the 900 W power level, showing 63.27% less consumption than the HA drying method.

  18. Field controlled experiments of mercury accumulation in crops from air and soil

    Energy Technology Data Exchange (ETDEWEB)

    Niu Zhenchuan [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Zhang Xiaoshan, E-mail: zhangxsh@rcees.ac.cn [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Zhangwei, E-mail: wangzhw@rcees.ac.cn [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Ci Zhijia [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)

    2011-10-15

    Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation. - Highlights: > Hg accumulation in crop organs was studied by OTCs and soil Hg enriched experiments. > Hg accumulation in foliages and roots was mainly from air and soil, respectively. > Air Hg had stronger influence than soil Hg on stem Hg accumulation. > Foliar Hg concentrations showed the trend of increase over growth stages. - Capsule Mercury accumulated in the aboveground organs of crop was mainly from the air.

  19. Field controlled experiments of mercury accumulation in crops from air and soil

    International Nuclear Information System (INIS)

    Niu Zhenchuan; Zhang Xiaoshan; Wang Zhangwei; Ci Zhijia

    2011-01-01

    Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation. - Highlights: → Hg accumulation in crop organs was studied by OTCs and soil Hg enriched experiments. → Hg accumulation in foliages and roots was mainly from air and soil, respectively. → Air Hg had stronger influence than soil Hg on stem Hg accumulation. → Foliar Hg concentrations showed the trend of increase over growth stages. - Capsule Mercury accumulated in the aboveground organs of crop was mainly from the air.

  20. Dry air oxidation kinetics of K-Basin spent nuclear fuel

    International Nuclear Information System (INIS)

    Abrefah, J.; Buchanan, H.C.; Gerry, W.M.; Gray, W.J.; Marschman, S.C.

    1998-06-01

    The safety and process analyses of the proposed Integrated Process Strategy (IPS) to move the N-Reactor spent nuclear fuel (SNF) stored at K-Basin to an interim storage facility require information about the oxidation behavior of the metallic uranium. Limited experiments have been performed on the oxidation reaction of SNF samples taken from an N-Reactor outer fuel element in various atmospheres. This report discusses studies on the oxidation behavior of SNF using two independent experimental systems: (1) a tube furnace with a flowing gas mixture of 2% oxygen/98% argon; and (2) a thermogravimetric system for dry air oxidation

  1. Analyzing drying characteristics and modeling of thin layers of peppermint leaves under hot-air and infrared treatments

    Directory of Open Access Journals (Sweden)

    Seyed-Hassan Miraei Ashtiani

    2017-06-01

    Full Text Available The drying kinetics of peppermint leaves was studied to determine the best drying method for them. Two drying methods include hot-air and infrared techniques, were employed. Three different temperatures (30, 40, 50 °C and air velocities (0.5, 1, 1.5 m/s were selected for the hot-air drying process. Three levels of infrared intensity (1500, 3000, 4500 W/m2, emitter-sample distance (10, 15, 20 cm and air speed (0.5, 1, 1.5 m/s were used for the infrared drying technique. According to the results, drying had a falling rate over time. Drying kinetics of peppermint leaves was explained and compared using three mathematical models. To determine coefficients of these models, non-linear regression analysis was used. The models were evaluated in terms of reduced chi-square (χ2, root mean square error (RMSE and coefficient of determination (R2 values of experimental and predicted moisture ratios. Statistical analyses indicated that the model with the best fitness in explaining the drying behavior of peppermint samples was the Logarithmic model for hot-air drying and Midilli model for infrared drying. Moisture transfer in peppermint leaves was also described using Fick’s diffusion model. The lowest effective moisture diffusivity (1.096 × 10−11 m2/s occurred during hot-air drying at 30 °C using 0.5 m/s, whereas its highest value (5.928 × 10−11 m2/s belonged to infrared drying using 4500 W/m2 infrared intensity, 0.5 m/s airflow velocity and 10 cm emitter-sample distance. The activation energy for infrared and hot-air drying were ranged from 0.206 to 0.439 W/g, and from 21.476 to 27.784 kJ/mol, respectively.

  2. Pollution impact of cement production on air, soil and water in a ...

    African Journals Online (AJOL)

    Pollution impact of cement production on air, soil and water in a production location in Nigeria. ... Journal of Science and Technology (Ghana) ... location from the pollution source, which served as control for particulate and soil sampling.

  3. Study of the morphology of corrosion features of natural graphite oxidised by dry and humid air

    International Nuclear Information System (INIS)

    Senevat, Jean

    1965-12-01

    The author reports a study which aimed at highlighting the morphology differences between corrosion features which affect flakes of natural graphite oxidised by dry air and by humid air. The study is based on observations made by optical and transmission electronic microscopy, this last one being performed on replicates. As the so-called 'Hennig' replicates did not result in a sufficient resolution of corrosion feature details, another method has been developed. Three classes of samples (in relationship with the rate of impurities present in samples) have been studied. Flakes have thus been sorted and each flake has then been oxidised at different wear rates. This highlights the influence of damages created by impurities in the lattice [fr

  4. Cold, dry air is associated with influenza and pneumonia mortality in Auckland, New Zealand.

    Science.gov (United States)

    Davis, Robert E; Dougherty, Erin; McArthur, Colin; Huang, Qiu Sue; Baker, Michael G

    2016-07-01

    The relationship between weather and influenza and pneumonia mortality was examined retrospectively using daily data from 1980 to 2009 in Auckland, New Zealand, a humid, subtropical location. Mortality events, defined when mortality exceeded 0·95 standard deviation above the mean, followed periods of anomalously cold air (ta.m. = -4·1, P < 0·01; tp.m. = -4·2, P < 0·01) and/or anomalously dry air (ta.m. = -4·1, P < 0·01; tp.m. = -3·8, P < 0·01) by up to 19 days. These results suggest that respiratory infection is enhanced during unusually cold conditions and during conditions with unusually low humidity, even in a subtropical location where humidity is typically high. © 2015 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  5. Sporulation and Germination patterns - hedging a bet on long term microbial survivability in dry soil

    Science.gov (United States)

    Claes, N.; Or, D.

    2012-04-01

    Soil hosts unparalleled diversity of microbial life that is constantly challenged by the vagaries of fluctuating ambient conditions. Desiccation stresses play a key role not only by directly affecting individual bacterial cells, but also by shaping diffusion pathways and cell dispersion. The gradual thinning and fragmentation of the aqueous environment during drying have led to different survival mechanisms including dormancy and sporulation, resulting in a highly resistive state capable of surviving extreme and prolonged environmental stresses until conditions improve in the future. Our aim is to investigate how temporal changes in hydration status shape microbial communities over time, based on simple survival strategy rules for each individual bacterium. The two survival strategies considered are dormancy and sporulation. Dormancy is the state in which bacterial cells significantly reduce their metabolism with minor morphological adaptations. The required energy and time for attaining this state are low relative to sporulation costs. Sporulation involves several morphological and biochemical changes that result in a resistive capsule that endures extreme stresses over long periods of time. The working hypothesis is that different micro-ecological conditions and community compositions would result from temporal patterns and magnitude of desiccation stresses. An Individual Based Model (IBM) considering habitats on rough soil surfaces and local effects of micro-hydrological conditions on dispersion and nutrient diffusion would enable systematic study of emerging communities over extended periods. Different population compositions are expected to emerge based on low and high frequency, duration and amplitudes of wetting-drying cycles reflecting relative success or failure of survival strategy.

  6. Mechanical Energy Propagation and Backscattering in Nominally Dry Soil: Imaging Buried Land Mines

    Science.gov (United States)

    Sen, Surajit

    2003-04-01

    The imaging of shallow buried objects in a complex medium, e.g., nominally dry sand, is an outstanding challenge. Such imaging is of relevance in connection with the detection and subsequent imaging of buried non-metallic anti-personnel land mines and in other applications. It has been shown that gentle mechanical impulses and low frequency sound waves with frequencies roughly between 150-350 Hz or so can penetrate distances of up to a foot in sand. Hence, such signals can potentially be useful in the detection and perhaps in the imaging of shallow buried objects. It is presently unclear whether high frequency signals can be effectively used to image shallow buried objects. Impulses can typically penetrate larger distances into sand and soil. Both impulses and continuous sound waves can be used for imaging shallow buried objects. The talk shall briefly review the state-of-the-art in low frequency sound propagation in soil and shall discuss the current understanding of impulse propagation and backscattering in nominally dry sand beds. It will be argued that impulse based imaging may have the potential to be a simple and fast way to detect and image small non-metallic mines. Research supported by the National Science Foundation Grant No. NSF-CMS 0070055.

  7. Change in dry matter and nutritive composition of Brachiaria humidicola grown in Ban Thon soil series

    Directory of Open Access Journals (Sweden)

    Jeerasak Chobtang

    2008-11-01

    Full Text Available This experiment was conducted to determine the change in dry matter and nutritive composition of Humidicola grass (Brachiaria humidicola grown in Ban Thon soil series (infertility soil as a function of growth age. One rai (0.16 ha of two-year-old pasture of fertilised Humidicola grass was uniformly cut and the regrowth samples were collected every twenty days. The samples were subjected to analysis for dry matter content and nutritive composition, i.e. crude protein, ash, calcium, phosphorus, neutral detergent fibre, acid detergent fibre, and acid detergent lignin. The results showed that while the yields of available forage and leaves increased curvilinearly (quadratic, p<0.05, the stem yield increased linearly (p<0.05 over sampling dates. The highest biomass accumulation rate was numerically observed between 40-60 days of regrowth. The concentrations of crude protein, ash, calcium and phosphorus decreased curvilinearly (quadratic, p<0.05 with advancing maturity and reached the lowest flat after 60 days of regrowth. The cell wall components, i.e. NDF, ADF and ADL, increased over the experimental period and reached the highest plateau at 40 days of regrowth. It was concluded that Humidicola grass should be grazed or preserved at the regrowth age of not over 60 days to maximise the utilisation of the grass.

  8. Effects of air temperature and velocity on the drying kinetics and product particle size of starch from arrowroot (Maranta arundinacae)

    Science.gov (United States)

    Caparanga, Alvin R.; Reyes, Rachael Anne L.; Rivas, Reiner L.; De Vera, Flordeliza C.; Retnasamy, Vithyacharan; Aris, Hasnizah

    2017-11-01

    This study utilized the 3k factorial design with k as the two varying factors namely, temperature and air velocity. The effects of temperature and air velocity on the drying rate curves and on the average particle diameter of the arrowroot starch were investigated. Extracted arrowroot starch samples were dried based on the designed parameters until constant weight was obtained. The resulting initial moisture content of the arrowroot starch was 49.4%. Higher temperatures correspond to higher drying rates and faster drying time while air velocity effects were approximately negligible or had little effect. Drying rate is a function of temperature and time. The constant rate period was not observed for the drying rate of arrowroot starch. The drying curves were fitted against five mathematical models: Lewis, Page, Henderson and Pabis, Logarithmic and Midili. The Midili Model was the best fit for the experimental data since it yielded the highest R2 and the lowest RSME values for all runs. Scanning electron microscopy (SEM) was used for qualitative analysis and for determination of average particle diameter of the starch granules. The starch granules average particle diameter had a range of 12.06 - 24.60 μm. The use of ANOVA proved that particle diameters for each run varied significantly with each other. And, the Taguchi Design proved that high temperatures yield lower average particle diameter, while high air velocities yield higher average particle diameter.

  9. Development of an Inline Dry Power Inhaler That Requires Low Air Volume.

    Science.gov (United States)

    Farkas, Dale; Hindle, Michael; Longest, P Worth

    2017-12-20

    Inline dry powder inhalers (DPIs) are actuated by an external air source and have distinct advantages for delivering aerosols to infants and children, and to individuals with compromised lung function or who require ventilator support. However, current inline DPIs either perform poorly, are difficult to operate, and/or require large volumes (∼1 L) of air. The objective of this study was to develop and characterize a new inline DPI for aerosolizing spray-dried formulations with powder masses of 10 mg and higher using a dispersion air volume of 10 mL per actuation that is easy to load (capsule-based) and operate. Primary features of the new low air volume (LV) DPIs are fixed hollow capillaries that both pierce the capsule and provide a continuous flow path for air and aerosol passing through the device. Two different configurations were evaluated, which were a straight-through (ST) device, with the inlet and outlet capillaries on opposite ends of the capsule, and a single-sided (SS) device, with both the inlet and outlet capillaries on the same side of the capsule. The devices were operated with five actuations of a 10 mL air syringe using an albuterol sulfate (AS) excipient-enhanced growth (EEG) formulation. Device emptying and aerosol characteristics were evaluated for multiple device outlet configurations. Each device had specific advantages. The best case ST device produced the smallest aerosol [mean mass median aerodynamic diameter (MMAD) = 1.57 μm; fine particle fraction <5 μm (FPF <5μm ) = 95.2%)] but the mean emitted dose (ED) was 61.9%. The best case SS device improved ED (84.8%), but produced a larger aerosol (MMAD = 2.13 μm; FPF <5μm  = 89.3%) that was marginally higher than the initial deaggregation target. The new LV-DPIs produced an acceptable high-quality aerosol with only 10 mL of dispersion air per actuation and were easy to load and operate. This performance should enable application in high and low flow

  10. Influence of warm air-drying on enamel bond strength and surface free-energy of self-etch adhesives.

    Science.gov (United States)

    Shiratsuchi, Koji; Tsujimoto, Akimasa; Takamizawa, Toshiki; Furuichi, Tetsuya; Tsubota, Keishi; Kurokawa, Hiroyasu; Miyazaki, Masashi

    2013-08-01

    We examined the effect of warm air-drying on the enamel bond strengths and the surface free-energy of three single-step self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and then wet ground with #600 silicon carbide (SiC) paper. The adhesives were applied according to the instructions of the respective manufacturers and then dried in a stream of normal (23°C) or warm (37°C) air for 5, 10, and 20 s. After visible-light irradiation of the adhesives, resin composites were condensed into a mold and polymerized. Ten samples per test group were stored in distilled water at 37°C for 24 h and then the bond strengths were measured. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The enamel bond strengths varied according to the air-drying time and ranged from 15.8 to 19.1 MPa. The trends for the bond strengths were different among the materials. The value of the γS⁺ component increased slightly when drying was performed with a stream of warm air, whereas that of the γS⁻ component decreased significantly. These data suggest that warm air-drying is essential to obtain adequate enamel bond strengths, although increasing the drying time did not significantly influence the bond strength. © 2013 Eur J Oral Sci.

  11. Effect of different air-drying time on the microleakage of single-step self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Horieh Moosavi

    2013-05-01

    Full Text Available Objectives This study evaluated the effect of three different air-drying times on microleakage of three self-etch adhesive systems. Materials and Methods Class I cavities were prepared for 108 extracted sound human premolars. The teeth were divided into three main groups based on three different adhesives: Opti Bond All in One (OBAO, Clearfil S3 Bond (CSB, Bond Force (BF. Each main group divided into three subgroups regarding the air-drying time: without application of air stream, following the manufacturer's instruction, for 10 sec more than manufacturer's instruction. After completion of restorations, specimens were thermocycled and then connected to a fluid filtration system to evaluate microleakage. The data were statistically analyzed using two-way ANOVA and Tukey-test (α = 0.05. Results The microleakage of all adhesives decreased when the air-drying time increased from 0 sec to manufacturer's instruction (p < 0.001. The microleakage of BF reached its lowest values after increasing the drying time to 10 sec more than the manufacturer's instruction (p < 0.001. Microleakage of OBAO and CSB was significantly lower compared to BF in all three drying time (p < 0.001. Conclusions Increasing in air-drying time of adhesive layer in one-step self-etch adhesives caused reduction of microleakage, but the amount of this reduction may be dependent on the adhesive components of self-etch adhesives.

  12. Extrapolating effects of conservation tillage on yield, soil moisture and dry spell mitigation using simulation modelling

    Science.gov (United States)

    Mkoga, Z. J.; Tumbo, S. D.; Kihupi, N.; Semoka, J.

    /ha) ( P < 0.05). Results also indicated a probability of 0.5 of getting higher yield in conservation than in conventional tillage practice. The conservation tillage treatment had the ability to even-out the acute and long intra-seasonal dry spells. For example a 36-days agricultural dry spell which occurred between 85th and 130th day after planting in the 1989/1990 season (in the CT treatment) was mitigated to zero days in the RR treatment by maintaining soil moisture above the critical point. Critical soil moisture for maize was measured at 0.55 of maximum soil moisture that can be depleted crop (0.55 D). It is concluded that conservation tillage practice where ripping and surface crop residues is used is much more effective in mitigating dry spells and increase productivity in a seasonal rainfall range of between 460 and 770 mm. It is recommended that farmers in the area adopt that type of conservation tillage because rainfall was in this range (460-770 mm) in 12 out of the past 24 years, indicating possibility of yield losses once in every 2 years.

  13. Results of Long-term Measurement of 222Rn Volume Activity in Soil Air

    International Nuclear Information System (INIS)

    Holy, K.; Matos, M.; Boem, R.; Stanys, T.; Hola, O.; Polaskova, A.

    1999-01-01

    Radon in the soil air was continuously monitored for four years. The measured volume activities differ one from another even three times. On the basis of the measured data the annual and average daily courses of the 222 Rn volume activity were studied for individual months. In annual courses the winter and also summer maxima of the 222 Rn volume activity were found out. The study of the average daily courses revealed that the oscillation of the 222 Rn volume activity about its average value during a day is only a few percent. For dry summer months a linear relation was found out between the changes of the 222 Rn volume activity and the changes of the atmospheric pressure in their average daily courses (Authors)

  14. Radioecological behaviour of elementary tritium, especially dry deposition and its dependence on soil porosity

    International Nuclear Information System (INIS)

    Foerstel, H.

    1997-01-01

    The inventory of fusion reactors mainly consists of deuterium and tritium. The amount of tritium of each reactor is equal to the natural inventory of the earth's atmo- and hydrosphere. Elementary tritium (HT) itself is not dangerous to man, for it is hardly dissolved in water, that is neither taken up by human tissues nor metabolized anywhere in our body. In contrast to HT the tritiated water HTO quickly exchanges with any wet surface and with the humidity of air. After an accidental release into the atmosphere the main pathway of intake into the human body is as HTO via the lung; its surface is comparable to a soccer playground. HT released into air will be quickly oxidised within the upper centimetres of the soil when the plume touches the ground. Each soil tested by us until now had oxidized HT, that had shown hydrogenase activity. Neither the biological function nor the catalytic system wee identified yet. The hypothesis of a correlation between hydrogenase activity and soil nitrogen fixation could not be confirmed (nitrogen fixation shows a leakage of hydrogen): nitrogen fixing plants (nodules) do not oxidize HT. The presentation will summarize ten years of work in the laboratory and in the field. A concise picture of the radioecological behaviour of elementary tritium after an accidental release could be obtained. The work was partly done as cooperation within the frame of the EU or within the International Union of Radioecology

  15. Laboratory test investigations on soil water characteristic curve and air permeability of municipal solid waste.

    Science.gov (United States)

    Shi, Jianyong; Wu, Xun; Ai, Yingbo; Zhang, Zhen

    2018-05-01

    The air permeability coefficient has a high correlation with the water content of municipal solid waste. In this study, continuous drying methodology using a tension meter was employed to construct the soil water characteristic curve of municipal solid waste (M-SWCC). The municipal solid waste air permeability test was conducted by a newly designed apparatus. The measured M-SWCC was well reproduced by the van Genuchten (V-G) model and was used to predict the parameters of typical points in M-SWCC, including saturated water content, field capacity, residual water content and water content at the inflection point. It was found that the M-SWCC was significantly influenced by void ratio. The final evaporation and test period of M-SWCC increase with the increase in void ratio of municipal solid waste. The evolution of air permeability coefficient with water content of municipal solid waste depicted three distinct characteristic stages. It was observed that the water contents that corresponded to the two cut-off points of the three stages were residual water content and water content at the inflection point, respectively. The air permeability coefficient of municipal solid waste decreased with the increase of the water content from zero to the residual water content. The air permeability coefficient was almost invariable when the water content increased from residual water content to the water content at the inflection point. When the water content of municipal solid waste exceeded the water content at the inflection point, the air permeability coefficient sharply decreased with the increase of water content.

  16. Environmental application of nanotechnology: air, soil, and water.

    Science.gov (United States)

    Ibrahim, Rusul Khaleel; Hayyan, Maan; AlSaadi, Mohammed Abdulhakim; Hayyan, Adeeb; Ibrahim, Shaliza

    2016-07-01

    Global deterioration of water, soil, and atmosphere by the release of toxic chemicals from the ongoing anthropogenic activities is becoming a serious problem throughout the world. This poses numerous issues relevant to ecosystem and human health that intensify the application challenges of conventional treatment technologies. Therefore, this review sheds the light on the recent progresses in nanotechnology and its vital role to encompass the imperative demand to monitor and treat the emerging hazardous wastes with lower cost, less energy, as well as higher efficiency. Essentially, the key aspects of this account are to briefly outline the advantages of nanotechnology over conventional treatment technologies and to relevantly highlight the treatment applications of some nanomaterials (e.g., carbon-based nanoparticles, antibacterial nanoparticles, and metal oxide nanoparticles) in the following environments: (1) air (treatment of greenhouse gases, volatile organic compounds, and bioaerosols via adsorption, photocatalytic degradation, thermal decomposition, and air filtration processes), (2) soil (application of nanomaterials as amendment agents for phytoremediation processes and utilization of stabilizers to enhance their performance), and (3) water (removal of organic pollutants, heavy metals, pathogens through adsorption, membrane processes, photocatalysis, and disinfection processes).

  17. Daily efficiency of flat-plate solar air collectors for grain drying

    Energy Technology Data Exchange (ETDEWEB)

    Ting, K.C.; Shove, G.C.

    1983-01-01

    Single cover flat-plate solar collectors incorporated into walls and roofs of farm buildings have been used to heat ambient air for low temperature grain drying systems. Large surface area and high airflow rate are common features of these collectors. The drying period may range from several days to several weeks. Therefore, a knowledge of the variations of the collectors' daily efficiencies with respect to their design parameters would be helpful in applying solar collectors to grain drying. The objective of this study was to develop a simpler means of direct calculation of a collector's daily efficiency based on its design parameters. Many factors, such as configuration of the collector, airflow rate, weather conditions, etc. will affect the performance of solar collectors. A large number of varied conditions need to be tested in order to investigate the effect of different parameters on the collector performance. To facilitate this investigation, a computer simulation model developed by Ting was used to calculate the daily efficiencies of collectors under different operating conditions. The computer model was verified by Morrison's experimental data. Based on the simulation results, a functional relationship was developed between the daily efficiencies of collectors and their design parameters.

  18. Latest Apple Drying Technologies: A Review

    OpenAIRE

    ÖZDEMİR, Yasin; SAYIN, Emir Olcay; KURULTAY, Şefik

    2009-01-01

    Drying is known as one of the oldest preservation methods and can be applicable to many fruits. Sun drying of apple has been known from ancient times. However, this technique is weather-dependent and has contamination problems such as dust, soil, sand particles and insects. Hot air drying of apples has low energy efficiency and requires longer drying period. The desire to eliminate these problems, prevent quality loss, and achieve fast and effective thermal processing has resulted in an incre...

  19. Effect mechanism of air deflectors on the cooling performance of dry cooling tower with vertical delta radiators under crosswind

    International Nuclear Information System (INIS)

    Zhao, Yuanbin; Long, Guoqing; Sun, Fengzhong; Li, Yan; Zhang, Cuijiao; Liu, Jiabin

    2015-01-01

    Highlights: • A 3D numerical model was set for NDDCTV to study the effect of air deflectors. • The air deflectors improve the tower performance by 1.375 °C at u c = 6 m/s for a case. • The air deflectors reduce the air inflow deviation angle θ d at most delta entries. • The reduced θ d can improve the cooling performance of former deteriorated columns. • Both the radial inflow air velocity and θ d impact the cooling performance of delta. - Abstract: To study the effect mechanism of air deflectors on dry cooling tower, a three dimensional numerical model was established, with full consideration of the delta structure. The accuracy and credibility of dry cooling tower numerical model were validated. By numerical model, the average air static pressure and the average radial inflow air velocity were computed and analyzed at delta air entry, sector air entry and exit faces. By the air inflow deviation angle θ d , the effect of air deflectors on the aerodynamic field around tower was analyzed. The water exit temperatures of θ −1 columns, θ +2 columns and cooling sectors were also presented to clarify the effect of air deflectors. It was found that the air deflectors improved the aerodynamic field around cooling columns. The reduced air inflow deviation degree at delta entry improved the cooling performance of deteriorated columns. Referring to the radial inflow air velocity u ra and the air inflow deviation degree at delta entry, the effect mechanism of air deflectors are clarified under crosswind

  20. Natural radioactivity content in soil and indoor air of Chellanam.

    Science.gov (United States)

    Mathew, S; Rajagopalan, M; Abraham, J P; Balakrishnan, D; Umadevi, A G

    2012-11-01

    Contribution of terrestrial radiation due to the presence of naturally occurring radionuclides in soil and air constitutes a significant component of the background radiation exposure to the population. The concentrations of natural radionuclides in the soil and indoor air of Chellanam were investigated with an aim of evaluating the environmental radioactivity level and radiation hazard to the population. Chellanam is in the suburbs of Cochin, with the Arabian Sea in the west and the Cochin backwaters in the east. Chellanam is situated at ∼25 km from the sites of these factories. The data obtained serve as a reference in documenting changes to the environmental radioactivity due to technical activities. Soil samples were collected from 30 locations of the study area. The activity concentrations of (232)Th, (238)U and (40)K in the samples were analysed using gamma spectrometry. The gamma dose rates were calculated using conversion factors recommended by UNSCEAR [United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. UNSCEAR (2000)]. The ambient radiation exposure rates measured in the area ranged from 74 to 195 nGy h(-1) with a mean value of 131 nGy h(-1). The significant radionuclides being (232)Th, (238)U and (40)K, their activities were used to arrive at the absorbed gamma dose rate with a mean value of 131 nGy h(-1) and the radium equivalent activity with a mean value of 162 Bq kg(-1). The radon progeny levels varied from 0.21 to 1.4 mWL with a mean value of 0.6 mWL. The thoron progeny varied from 0.34 to 2.9 mWL with a mean value of 0.85 mWL. The ratio between thoron and radon progenies varied from 1.4 to 2.3 with a mean of 1.6. The details of the study, analysis and results are discussed.

  1. Direct observation of local xylem embolisms induced by soil drying in intact Zea mays leaves.

    Science.gov (United States)

    Ryu, Jeongeun; Hwang, Bae Geun; Kim, Yangmin X; Lee, Sang Joon

    2016-04-01

    The vulnerability of vascular plants to xylem embolism is closely related to their stable long-distance water transport, growth, and survival. Direct measurements of xylem embolism are required to understand what causes embolism and what strategies plants employ against it. In this study, synchrotron X-ray microscopy was used to non-destructively investigate both the anatomical structures of xylem vessels and embolism occurrence in the leaves of intact Zea mays (maize) plants. Xylem embolism was induced by water stress at various soil drying periods and soil water contents. X-ray images of dehydrated maize leaves showed that the ratio of gas-filled vessels to all xylem vessels increased with decreased soil water content and reached approximately 30% under severe water stress. Embolism occurred in some but not all vessels. Embolism in maize leaves was not strongly correlated with xylem diameter but was more likely to occur in the peripheral veins. The rate of embolism formation in metaxylem vessels was higher than in protoxylem vessels. This work has demonstrated that xylem embolism remains low in maize leaves under water stress and that there xylem has characteristic spatial traits of vulnerability to embolism. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Effect of Particle Size and Soil Compaction on Gas Transport Parameters in Variably Saturated, Sandy Soils

    DEFF Research Database (Denmark)

    Hamamoto, Shoichiro; Møldrup, Per; Kawamoto, Ken

    2009-01-01

    The soil gas diffusion coefficient (Dp) and air permeability (ka) and their dependency on soil air content ( ) control gas diffusion and advection in soils. This study investigated the effects of average particle size (D50) and dry bulk density ( b) on Dp and ka for six sandy soils under variably...

  3. Aspergillus and Penicillium (Eurotiales: Trichocomaceae) in soils of the Brazilian tropical dry forest: diversity in an area of environmental preservation.

    Science.gov (United States)

    Barbosa, Renan do Nascimento; Bezerra, Jadson Diogo Pereira; Costa, Phelipe Manoel Oller; de Lima-Júnior, Nelson Correia; Alves de Souza Galvão, Ivana Roberta Gomes; Alves dos Santos-Júnior, Anthony; Fernandes, Maria José; de Souza-Motta, Cristina Maria; Oliveira, Neiva Tinti

    2016-03-01

    Soil is a complex biological system that plays a key role for plants and animals, especially in dry forests such as the Caatinga. Fungi from soils, such as Aspergillus and Penicillium, can be used as bioindica- tors for biodiversity conservation. The aim of this study was to isolate and identify species of Aspergillus and Penicillium in soil, from the municipalities of Tupanatinga and Ibimirim, with dry forests, in the Catimbau National Park. Five collections were performed in each area during the drought season of 2012, totaling 25 soil samples per area. Fungi were isolated by suspending soil samples in sterile distilled water and plating on Sabouraud Agar media plus Chloramphenicol and Rose Bengal, and Glycerol Dicloran Agar. Isolates were identified by morphological taxonomy in the Culture Collection Laboratory and confirmed by sequencing of the Internal Transcribed Spacer of rDNA. A total of 42 species were identified, of which 22 belong to the genus Aspergillus and 20 to Penicillium. Penicillium isolates showed uniform distribution from the collecting area in Tupanatinga, and the evenness indices found were 0.92 and 0.88 in Tupanatinga and Ibimirim, respectively. Among isolates of Aspergillus evenness, the value found in Tupanatinga (0.85) was very close to that found in Ibimirim (0.86). High diversity and low dominance of fungi in soil samples was observed. These results con- tributed to the estimation of fungal diversity in dry environments of the Caatinga, where diversity is decreasing in soils that have undergone disturbance.

  4. Role of Biotic and Abiotic Processes on Soil CO2 Dynamics in the McMurdo Dry Valleys, Antarctica

    Science.gov (United States)

    Risk, D. A.; Macintyre, C. M.; Lee, C.; Cary, C.; Shanhun, F.; Almond, P. C.

    2016-12-01

    In the harsh conditions of the Antarctic Dry Valleys, microbial activity has been recorded via measurements of soil carbon dioxide (CO2) concentration and surface efflux. However, high temporal resolution studies in the Dry Valleys have also shown that abiotic solubility-driven processes can strongly influence (and perhaps even dominate) the CO2 dynamics in these low flux environments and suggests that biological activity may be lower than previously thought. In this study, we aim to improve our understanding of CO2 dynamics (biotic and abiotic) in Antarctic Dry Valley soils using long-term automated measurements of soil CO2 surface flux and soil profile concentration at several sites, often at sub-diel frequency. We hypothesize that soil CO2 variations are driven primarily by environmental factors affecting CO2 solubility in soil solution, mainly temperature, and that these processes may even overprint biologic production in representative Dry Valley soils. Monitoring of all sites revealed only one likely biotic CO2 production event, lasting three weeks during the Austral summer and reaching fluxes of 0.4 µmol/m2/s. Under more typical low flux conditions (sampling campaigns. Subsurface CO2 monitoring and a lab-controlled Antarctic soil simulation experiment confirmed that abiotic processes are capable of dominating soil CO2 variability. Diel temperature cycles crossing the freezing boundary revealed a dual abiotic cycle of solubility cycling and gas exclusion from ice formation observed only by high temporal frequency measurements (30 min). This work demonstrates a need for a numerical model to partition the dynamic abiotic processes underlying any biotic CO2 production in order to understand potential climate-change induced increases in microbial productivity in terrestrial Antarctica.

  5. Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

    Science.gov (United States)

    Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

    2016-11-01

    Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

  6. Nitrogen supply modulates the effect of changes in drying-rewetting frequency on soil C and N cycling and greenhouse gas exchange.

    Science.gov (United States)

    Morillas, Lourdes; Durán, Jorge; Rodríguez, Alexandra; Roales, Javier; Gallardo, Antonio; Lovett, Gary M; Groffman, Peter M

    2015-10-01

    Climate change and atmospheric nitrogen (N) deposition are two of the most important global change drivers. However, the interactions of these drivers have not been well studied. We aimed to assess how the combined effect of soil N additions and more frequent soil drying-rewetting events affects carbon (C) and N cycling, soil:atmosphere greenhouse gas (GHG) exchange, and functional microbial diversity. We manipulated the frequency of soil drying-rewetting events in soils from ambient and N-treated plots in a temperate forest and calculated the Orwin & Wardle Resistance index to compare the response of the different treatments. Increases in drying-rewetting cycles led to reductions in soil NO3- levels, potential net nitrification rate, and soil : atmosphere GHG exchange, and increases in NH4+ and total soil inorganic N levels. N-treated soils were more resistant to changes in the frequency of drying-rewetting cycles, and this resistance was stronger for C- than for N-related variables. Both the long-term N addition and the drying-rewetting treatment altered the functionality of the soil microbial population and its functional diversity. Our results suggest that increasing the frequency of drying-rewetting cycles can affect the ability of soil to cycle C and N and soil : atmosphere GHG exchange and that the response to this increase is modulated by soil N enrichment. © 2015 John Wiley & Sons Ltd.

  7. Cool and dry weather enhances the effects of air pollution on emergency IHD hospital admissions.

    Science.gov (United States)

    Qiu, Hong; Yu, Ignatius Tak-Sun; Wang, Xiaorong; Tian, Linwei; Tse, Lap Ah; Wong, Tze Wai

    2013-09-20

    Associations between ambient pollution and cardiovascular morbidity including ischemic heart disease (IHD) have been confirmed. Weather factors such as temperature, season and relative humidity (RH) may modify the effects of pollution. We conducted this study to examine the effects of air pollution on emergency IHD hospital admissions varied across seasons and RH levels, and to explore the possible joint modification of weather factors on pollution effects. Daily time series of air pollution concentrations, mean temperature and RH were collected from IHD hospital admissions from 1998 to 2007 in Hong Kong. We used generalized additive Poisson models with interaction term to estimate the pollution effects varied across seasons and RH levels, after adjusting for time trends, weather conditions, and influenza outbreaks. An increase in the detrimental effects of air pollution in cool season and on low humidity days was observed. In the cool and dry season, a 10 μg/m(3) increment of lag03 exposure was associated with an increase of emergency IHD admissions by 1.82% (95% CI: 1.24-2.40%), 3.89% (95% CI: 3.08-4.70%), and 2.19% (95% CI: 1.33-3.06%) for particles with an aerodynamic diameter less than 10 μm (PM10), nitrogen dioxide (NO2), and ozone (O3), respectively. The effects of pollutants decreased greatly and lost statistical significance in the warm and humid season. We found season and RH jointly modified the associations between ambient pollution and IHD admissions, resulting in increased IHD admissions in the cool and dry season and reduced admissions in the warm and humid season. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  8. Thermal comfort in air-conditioned mosques in the dry desert climate

    Energy Technology Data Exchange (ETDEWEB)

    Al-ajmi, Farraj F. [Department of Civil Engineering, College of Technological Studies, Shuwaikh 70654 (Kuwait)

    2010-11-15

    In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (T{sub n}) of the prayers is found to be 26.1 C, while that for PMV is 23.3 C. Discrepancy of these values is in fact about 2.8 C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait. (author)

  9. Soil Water Retention and Relative Permeability for Conditions from Oven-Dry to Full Saturation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.

    2011-11-04

    Common conceptual models for unsaturated flow often rely on the oversimplified representation of medium pores as a bundle of cylindrical capillaries and assume that the matric potential is attributed to the capillary force only. The adsorptive surface forces are ignored. It is often assumed that aqueous flow is negligible when a soil is near or at the residual water content. These models are successful at high and medium water contents but often give poor results at low water contents. These models do not apply to conditions at which the water content is less than the residual water content. We extend the lower bound of existing water-retention functions and conductivity models from residual water content to the oven-dry condition (i.e., zero water content) by defining a state-dependent, residual-water content for a soil drier than a critical value. Furthermore, a hydraulic conductivity model for smooth uniform spheres was modified by introducing a correction factor to describe the film flow-induced hydraulic conductivity for natural porous media. The total unsaturated hydraulic conductivity is the sum of those due to capillary and film flow. The extended retention and conductivity models were verified measurements. Results show that, when the soil is at high and intermediate water content, there is no difference between the un-extended and the extended models; when the soil is at low water content, the un-extended models overestimate the water content but underestimate the conductivity. The extended models match the retention and conductivity measurements well.

  10. Differences on nitrogen availability in a soil amended with fresh, composted and thermally-dried sewage sludge.

    Science.gov (United States)

    Tarrasón, D; Ojeda, G; Ortiz, O; Alcañiz, J M

    2008-01-01

    Anaerobically-digested sludge called fresh sludge (F), composted sludge (C) and thermally-drying sludge (T), all from the same batch, were applied to the surface of a calcareous Udic Calciustept with loamy texture. Dosage equivalent was 10 t ha(-1) of dry matter. The concentration of mineral nitrogen (ammonium and nitrate) in the soil was measured in order to estimate the effects of the post-treatments to which the different kinds of sewage sludge are subjected in relation to the availability of N in the surface layer of the soil. The most significant differences in NH(4)-N and NO(3)-N concentrations due to the transformation of the organic matter were observed during the first three weeks following soil amendment. Thermally-dried and composted sludge initially displayed higher concentrations of ammonium and nitrate in soil. Five months after the amendment, soil applied with fresh sludge showed the highest concentrations of NH(4)-N and NO(3)-N (6.1 and 36.6 mg kg(-1), respectively). It is clear that the processes of composting and thermal-drying influence the bioavailability of nitrogen from the different types of sewage sludge.

  11. Aerosol Particles from Dried Salt-Lakes and Saline Soils Carried on Dust Storms over Beijing

    Directory of Open Access Journals (Sweden)

    Xingying Zhang

    2009-01-01

    Full Text Available Characteristics of individual particles from a super dust storm (DS on 20 March 2002, and those of non dust storm aero sols for Beijing (NDS and Duolun (DL (a desert area are determined using a variety of methods. In China, typically the source of aero sols in dust storms is thought to be deserts with alumino silicates being the main constituent particles; how ever, this does not reflect a complete analysis with our evidence indicating potential alternate dust sources along the storm's trans port path. Individual particle anal y sis of aero sols collected from a super dust storm on 20 March 2002 in Beijing shows that among all the 14 elements measured, only S and Cl have re mark able positive correlation. 82.5% of all particles measured contained both S and Cl, and the relative mass per cent age of S and Cl in these particles is much higher than the average of all particles. 62.0% of all particles contained S, Cl, and Na, in which the concentration of Na is 1.4 times higher than average. PMF (Positive Matrix Factorization anal y sis indicates that NaCl and Na2SO4 are major components of these particles with S and Cl showing significant positive correlation. More over, SO4 2- and Cl- also show significant positive correlation in bulk aero sol analysis. XPS (X-ray Pho to electron Spectros copy analysis of the surface of aero sols demonstrates that concentrations of Na and S on particles from the dust storm are higher than those from non-dust storm particles in Beijing and also for particles from. It is very likely that particles enriched with S, Cl, and Na is from the surface soils of dried salt-lakes and saline soils enriched with chloride and sulfate. This evidence demonstrates that be sides deserts, surface soils from dry salt-lakes and saline soils of arid and semi-arid areas are also sources of particulates in dust storms over Beijing.

  12. Interaction between Soil Moisture and Air Temperature in the Mississippi River Basin

    Science.gov (United States)

    Increasing air temperatures are expected to continue in the future. The relation between soil moisture and near surface air temperature is significant for climate change and climate extremes. Evaluation of the relations between soil moisture and temperature was performed by devel...

  13. Antioxidant capacity and total phenolic content of air-dried cape gooseberry (Physalis peruviana L. at different ripeness stages

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Narváez-Cuenca

    2014-08-01

    Full Text Available Because the use of drying at high temperatures might negatively affect the functional properties of fruits, the effect of air-drying at 60°C on the total phenolic content (TPC and antioxidant capacity (AOC of cape gooseberry fruit was evaluated at three ripeness stages. The AOC was evaluated with 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid (ABTS , ferric reducing ability of plasma (FRAP, 1,1-diphenyl-2-picrylhydrazyl (DPPH, and beta-carotene-linoleate assays. The TPC and AOC increased in the fresh fruit as the ripeness stage increased. The TPC increased from 401.8±19.8 to 569.3±22.3 mg GA E/100 g dry weight (DW. The AOC values obtained with ABTS in the fresh fruit (ranging from 79.4±4.5 to 132.7±12.9 mumol trolox/g fruit DW were comparable to those obtained with FRAP (ranging from 82.9±16.3 to 153.9±31.7 mumol trolox/g fruit DW. The values assessed with DPPH ranged from 21.0±3.2 to 34.1±5.1 mumol trolox/g fruit DW. The beta-carotene-linoleate assay gave values ranging from 5.8±1.1 to 12.7±2.0 mumol a-tocoferol/g fruit DW. Air-drying the cape gooseberry fruit had a small influence on the TPC. The air-dried fruit had AOC values ranging from 27 to 164% of the value of the fresh fruit. While the ABTS assay produced higher values in the air-dried fruit than in the fresh fruit, the FRAP, DPPH, and beta-carotene-linoleate assays resulted in lower values in the air-dried fruit.

  14. Comparison of salt solution and air drying methods for moisture fixation in highly porous building materials

    DEFF Research Database (Denmark)

    Antonov, Yovko Ivanov; Jensen, Rasmus Lund; Møldrup, Per

    2017-01-01

    In recent years, research has identified some bio-based, porous building materials as good or excellent regulators of moisture in buildings. The ability of a material to absorb, release and store moisture is described by vapour sorption isotherms. It is necessary input to simulations of indoor...... building materials by a standardized testing method, using saturated salt solutions. Furthermore, results from the standard method are compared to values of moisture content for the same materials, obtained by air-drying at different relative humidity. This is done with the aim to compare the findings from...... the two methods with respect to time and repeatability of the results. Derived isotherms are further used as direct input in the building simulation software BSim, which is capable of predicting indoor environment parameters by solving coupled, transient heat and moisture transport equations using finite...

  15. Air cooling of refrigerating loops: 'dry-hybrid' systems; Refroidissement par air des circuits frigorifiques: les systemes ''secs hybrides''

    Energy Technology Data Exchange (ETDEWEB)

    Becker, W. [Societe Jaggi-Gunter (Switzerland)

    2003-02-01

    Different type of cooling systems can be implemented on coldness production plants. The choice very often depends on the initial investment, but from a technical and economical point of view, this choice is not necessary the best solution. Thus, it can be useful to know the different existing systems and their exploitation costs with respect to the expected needs. A particular solution which uses a 'dry-hybrid' cooler is presented in this study: 1 - open-loop evaporative cooler; 2 - open-loop evaporative cooler with intermediate exchanger; 3 - close-loop evaporative cooler; 4 - dry-cooler; 5 - dry cooler with spraying in the air flow way; 6 - dry cooler with counterflow spraying; 7 - hybrid dry cooler; 8 - example of a realization in Germany: technical and economical value of the project, description of compared solutions and hypotheses, interpretation of results. (J.S.)

  16. A mouse dry eye model induced by topical administration of the air pollutant particulate matter 10.

    Science.gov (United States)

    Li, Juan; Tan, Gang; Ding, Xiaoyan; Wang, Yahong; Wu, Anhua; Yang, Qichen; Ye, Lei; Shao, Yi

    2017-12-01

    To introduce a novel dry eye mouse model induced by topical administration of the air pollutant particulate matter 10 (PM 10 ). A total of 60 male BALB/c mice were used in this study and divided into two groups: group A (PBS eye drops, n=30) and group B (PM 10 eye drop group, n=30). Each treatment was dosed four times a day, every time 50ul with the concentration of 5mg/ml PM10, for 14 consecutive days in the right eye. The clinical manifestations of dry eye were measured before therapy and 4, 7 and 14days post-treatment respectively, which included the tear volume, tear break-up (BUT) time, corneal fluorescein staining, rose bengal staining, Lissamine Green staining and inflammatory index. Eye samples were collected on D14 and examined by histologic light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), corneal cytokeration 10 (K10) immunnostaining, and tumor necrosis factor-α (TNF-α), NF-κB-p65 and NF-κB Western Blot analysis. At 0d, 7d and 14d, there were no statistical changes in tear volume, BUT after treatment (P>0.05) with PBS in group A. In group B, all items showed statistical differences at each time point (Plevels of K10 and reduced number of goblet cells in the conjunctival fornix in group B. PM 10 significantly increased the levels of TNF-α, NF-κB-p65 and NF-κB in the cornea. PM 10 can damage the tear film function and cause the destruction of the structural organization of ocular surface in mice. Topical administration of PM 10 in mice induces ocular surface changes that are similar to those of dry eye in humans, representing a novel model of DES. Copyright © 2017. Published by Elsevier Masson SAS.

  17. Estimating saturated hydraulic conductivity and air permeability from soil physical properties using state-space analysis

    DEFF Research Database (Denmark)

    Poulsen, Tjalfe; Møldrup, Per; Nielsen, Don

    2003-01-01

    and gaseous chemicals in the vadose zone. In this study, three modeling approaches were used to identify the dependence of saturated hydraulic conductivity (K-S) and air permeability at -100 cm H2O soil-water potential (k(a100)) on soil physical properties in undisturbed soil: (i) Multiple regression, (ii......) ARIMA (autoregressive integrated moving average) modeling, and (iii) State-space modeling. In addition to actual soil property values, ARIMA and state-space models account for effects of spatial correlation in soil properties. Measured data along two 70-m-long transects at a 20-year old constructed......Estimates of soil hydraulic conductivity (K) and air permeability (k(a)) at given soil-water potentials are often used as reference points in constitutive models for K and k(a) as functions of moisture content and are, therefore, a prerequisite for predicting migration of water, air, and dissolved...

  18. Spray washing, absorbent cornstarch powder, and dry time to reduce bacterial numbers on soiled transport cage flooring

    Science.gov (United States)

    Broiler transport cages are often used repeatedly without washing and fecal matter deposited on the floor surface can transfer Campylobacter from one flock to another. Allowing feces to dry is an effective but slow and logistically impractical means to kill Campylobacter in soiled transport cages. ...

  19. The relationship between plant species richness and soil pH vanishes with increasing aridity across Eurasian dry grasslands

    Czech Academy of Sciences Publication Activity Database

    Palpurina, S.; Wagner, V.; von Wehrden, H.; Hájek, M.; Horsák, M.; Brinkert, A.; Hölzel, N.; Wesche, K.; Kamp, J.; Hájková, Petra; Danihelka, Jiří; Lustyk, P.; Merunková, K.; Preislerová, Z.; Kočí, M.; Kubešová, S.; Cherosov, M. M.; Ermakov, N.; German, D.; Gogoleva, P. A.; Lashchinsky, N.; Martynenko, V. B.; Chytrý, M.

    2017-01-01

    Roč. 26, č. 4 (2017), s. 425-434 ISSN 1466-822X Institutional support: RVO:67985939 Keywords : diversity-environment relationship * dry grassland * precipitation * soil pH Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 6.045, year: 2016

  20. Roles of Arbuscular Mycorrhizal Fungi and Soil Abiotic Conditions in the Establishment of a Dry Grassland Community

    Czech Academy of Sciences Publication Activity Database

    Knappová, Jana; Pánková, Hana; Münzbergová, Zuzana

    2016-01-01

    Roč. 11, č. 7 (2016), s. 1-24 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA15-11635S Institutional support: RVO:67985939 Keywords : AMF * dry grassland commnunity * soil abiotic conditions Subject RIV: EF - Botanics Impact factor: 2.806, year: 2016

  1. Small-angle neutron scattering investigation of polyurethane aged in dry and wet air

    Directory of Open Access Journals (Sweden)

    Q. Tian

    2014-05-01

    Full Text Available The microstructures of Estane 5703 aged at 70°C in dry and wet air have been studied by small-angle neutron scattering. The samples were swollen in deuterated toluene for enhancing the contrast. The scattering data show the characteristic domain structure of polyurethanes consisting of soft and hard segments. Debye-Anderson-Brumberger function used with hard sphere structure factor, and the Teubner-Strey model are used to analyze the two-phase domain structure of the polymer. The combined effects of temperature and humidity have a strong disruption effect on the microstructures of Estane. For the sample aged at 70°C in wet air for 1 month, the domain size, described by the correlation length, increases from 2.3 to 3.8 nm and their distance, expressed by hard-sphere interaction radius, increases from 8.4 to 10.6 nm. The structure development is attributed to degradation of polymer chains as revealed by gel permeation chromatography. The hydrolysis of ester links on polymer backbone at 70°C in the presence of water humidity is the main reason for the changes of the microstructure. These findings can contribute to developing predictive models for the safety, performance, and lifetime of polyurethanes.

  2. Air-drying of cells, the novel conditions for stimulated synthesis of triacylglycerol in a Green Alga, Chlorella kessleri.

    Directory of Open Access Journals (Sweden)

    Takuma Shiratake

    Full Text Available Triacylglycerol is used for the production of commodities including food oils and biodiesel fuel. Microalgae can accumulate triacylglycerol under adverse environmental conditions such as nitrogen-starvation. This study explored the possibility of air-drying of green algal cells as a novel and simple protocol for enhancement of their triacylglycerol content. Chlorella kessleri cells were fixed on the surface of a glass fibre filter and then subjected to air-drying with light illumination. The dry cell weight, on a filter, increased by 2.7-fold in 96 h, the corresponding chlorophyll content ranging from 1.0 to 1.3-fold the initial one. Concomitantly, the triacylglycerol content remarkably increased to 70.3 mole% of fatty acids and 15.9% (w/w, relative to total fatty acids and dry cell weight, respectively, like in cells starved of nitrogen. Reduction of the stress of air-drying by placing the glass filter on a filter paper soaked in H2O lowered the fatty acid content of triacylglycerol to 26.4 mole% as to total fatty acids. Moreover, replacement of the H2O with culture medium further decreased the fatty acid content of triacylglycerol to 12.2 mole%. It thus seemed that severe dehydration is required for full induction of triacylglycerol synthesis, and that nutritional depletion as well as dehydration are crucial environmental factors. Meanwhile, air-drying of Chlamydomonas reinhardtii cells increased the triacylglycerol content to only 37.9 mole% of fatty acids and 4.8% (w/w, relative to total fatty acids and dry cell weight, respectively, and a marked decrease in the chlorophyll content, on a filter, of 33%. Air-drying thus has an impact on triacylglycerol synthesis in C. reinhardtii also, however, the effect is considerably limited, owing probably to instability of the photosynthetic machinery. This air-drying protocol could be useful for the development of a system for industrial production of triacylglycerol with appropriate selection of the

  3. Assessment of the environmental microbiological cross contamination following hand drying with paper hand towels or an air blade dryer.

    Science.gov (United States)

    Margas, E; Maguire, E; Berland, C R; Welander, F; Holah, J T

    2013-08-01

    This study compared the potential for cross contamination of the surrounding environment resulting from two different hand-drying methods: paper towels and the use of an air blade dryer. One hundred volunteers for each method washed their hands and dried them using one of the two methods. Bacterial contamination of the surrounding environment was measured using settle plates placed on the floor in a grid pattern, air sampling and surface swabs. Both drying methods produced ballistic droplets in the immediate vicinity of the hand-drying process. The air blade dryer produced a larger number of droplets which were dispersed over a larger area. Settle plates showed increased microbial contamination in the grid squares which were affected by ballistic droplets. Using the settle plates counts, it was estimated that approx. 1.7 × 10(5) cfu more micro-organisms were left on the laboratory floor (total area approx. 17.15 m(2)) after 100 volunteers used an air blade dryer compared to when paper towels were used. The two drying methods led to different patterns of ballistic droplets and levels of microbial contamination under heavy use conditions. Whilst the increase in microbial levels in the environment is not significant if only nonpathogenic micro-organisms are spread, it may increase the risk of pathogen contamination of the environment when pathogens are occasionally present on people's hands. The study suggests that the risk of cross contamination from the washroom users to the environment and subsequent users should be considered when choosing a hand-drying method. The data could potentially give guidance following the selection of drying methods on implementing measures to minimise the risk of cross contamination. © 2013 The Society for Applied Microbiology.

  4. Influence of 60Co γ irradiation pre-treatment on characteristics of hot air drying sweet potato slices

    International Nuclear Information System (INIS)

    Jiang Ning; Liu Chunquan; Li Dajing; Liu Xia; Yan Qimei

    2012-01-01

    The influences of irradiation, hot air temperature and thicknesses of the slices on the characters of dehydration and surface temperature of 60 Co γ-rays irradiated sweet potato were investigated. Meanwhile, microscopic observation and determination of water activity of irradiated sweet potato were conducted. The results show that the drying rate and the surface temperature rose with the increasing of irradiation dose. When the dry basis moisture content was 150%, the drying rate of the samples were 1.92, 1.97, 2.05, 2.28, 3.12% /min while the irradiation dose were 0, 2, 5, 8, 10 kGy, and the surface temperature were 48.5 ℃, 46.3℃, 44.5 ℃, 42.2 ℃, 41.5 ℃, respectively. With higher air temperature and thinner of the sweet potato slices, the dehydration of the irradiated sweet potato slices were faster. The drying speed of sweet potato slices at 85 ℃ was 170 min faster than that of 65 ℃. The drying speed of 7 mm sweet potato slices was 228 min faster than that of 3 mm sample. The cell wall and the vacuole of the sweet potato slices were broken after irradiation, and its water activity increased with the increase is radiation dose. The water activity of the irradiated samples were 0.92, 0.945, 0.958, 0.969, 0.979 with the irradiation doses of 0, 2, 5, 8, 10 kGy, respectively. The hot air drying rate, surface temperature and water activity of sweet potato are significantly impacted by irradiation. The conclusion provides a theoretical foundation for further processing technology of combined radiation and hot air drying sweet potato. (authors)

  5. Thermohydraulic modeling of the dry air passive containment cooling system process in the Westinghouse AP-600 ALWR

    Energy Technology Data Exchange (ETDEWEB)

    Harari, R; Weis, Y; Barnea, Y [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    Following postulated events of a LOCA, the passive Containment Cooling System (PCCS) uses dry air to transfer the residual heat by natural circulation. The air flow path, designed between the steel reactor containment hot shell and the concrete shield building, creates an open thermosyphon. The purpose of this inherently safe process is to assure the long term steady-state cooling of the nuclear core after an emergency shutdown (authors).

  6. Wheel traffic effect on air-filled porosity and air permeability in a soil catena across the wheel rut

    DEFF Research Database (Denmark)

    Berisso, Feto Esimo; Schjønning, Per; Lamandé, Mathieu

    might induce different effects on soil physical properties. The objective of this study was to investigate the impact of vehicle traffic on soil physical properties and air permeability by systematic collection of samples in a transect running from the center to the outside of the wheel rut. A field...... catena running from center of the wheel rut to un wheeled part of the field ( 0, 20, 40, 50,60 and 400 cm horizontal distance). We measured water retention and air permeability (ka) at -30, -100 and -300 hPa matric potentials. At -100 hPa, we obtained consistently lower air filled under the wheel rut......The impact of wheel traffic on soil physical properties is usually quantified by randomly collecting soil cores at specific depths below the wheeled surface. However, modeling studies as well as few measurements indicated a non-uniform stress distribution in a catena across the wheel rut, which...

  7. Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model.

    Science.gov (United States)

    Garcia, L; Bedos, C; Génermont, S; Braud, I; Cellier, P

    2011-09-01

    Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization

  8. Drying characteristics of whole Musa AA group ‘Kluai Leb Mu Nang’ using hot air and infrared vacuum

    Science.gov (United States)

    Kulketwong, C.; Thungsotanon, D.; Suwanpayak, N.

    2017-06-01

    Dried Musa AA group ‘Kluai Leb Mu Nang’ are the famous processing goods of Chumphon province, the south of Thailand. In this paper, we improved the qualities of whole Musa AA group ‘Kluai leb Mu Nang’ by using the hot air and infrared vacuum (HA and infrared vacuum) drying method which has two stages. The first stage of the method is the hot air (HA) and hot air-infrared (HAI) drying for rapidly reducing the moisture content and the drying times at atmospheric pressure, and the second stage, the moisture content, and color of the samples can be controlled by the HA and infrared vacuum drying. The experiment was evaluated by the terms of firmness, color change, moisture content, vacuum pressure and energy consumption at various temperatures. The results were found that the suitable temperature of the HAI and HA and infrared vacuum drying stages at 70°C and 55°C, respectively, while the suitable vacuum pressure in the second process was -0.4 bar. The samples were dried in a total of 28 hrs using 13.83 MJ/kg of specific energy consumption (stage 1 with 8.8 MJ/kg and stage 2 of 5.03 MJ/kg). The physical characteristics of the 21% (wb) of dried bananas can be measured the color change, L*=38.56, a*=16.47 and b*=16.3, was approximate the goods from the local market, whereas the firmness of them was more tender and shown a value of 849.56 kN/m3.

  9. CFD Analysis on the Passive Heat Removal by Helium and Air in the Canister of Spent Fuel Dry Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Do Young; Jeong, Ui Ju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2016-05-15

    In the current commercial design, the canister of the dry storage system is mainly backfilled with helium gas. Helium gas shows very conductive behavior due to high thermal conductivity and small density change with temperature. However, other gases such as air, argon, or nitrogen are expected to show effective convective behavior. Thus these are also considered as candidates for the backfill gas to provide effective coolability. In this study, to compare the dominant cooling mechanism and effectiveness of cooling between helium gas and air, a computational fluid dynamics (CFD) analysis for the canister of spent fuel dry storage system with backfill gas of helium and air is carried out. In this study, CFD simulations for the helium and air backfilled gas for dry storage system canister were carried out using ANSYS FLUENT code. For the comparison work, two backfilled fluids were modeled with same initial and boundary conditions. The observed major difference can be summarized as follows. - The simulation results showed the difference in dominant heat removal mechanism. Conduction for helium, and convection for air considering Reynolds number distribution. - The temperature gradient inside the fuel assembly showed that in case of air, more effective heat mixing occurred compared to helium.

  10. Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

    Science.gov (United States)

    Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

    2018-02-01

    While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs. Copyright © 2017 Elsevier Ltd. All

  11. Performance of a solar dryer using hot air from roof-integrated solar collectors for drying herbs and spices

    Energy Technology Data Exchange (ETDEWEB)

    Janjai, S.; Tung, P. [Silpakorn University, Pathom (Thailand). Dept. of Physics

    2005-11-01

    A solar dryer for drying herbs and spices using hot air from roof-integrated solar collectors was developed. The dryer is a bin type with a rectangular perforated floor. The bin has a dimension of 1.0 m x 2.0 m x 0.7 m. Hot air is supplied to the dryer from fiberglass-covered solar collectors, which also function as the roof of a farmhouse. The total area of the solar collectors is 72 m{sup 2}. To investigate its performance, the dryer was used to dry four batches of rosella flowers and three batches of lemon-grasses during the year 2002-2003. The dryer can be used to dry 200 kg of rosella flowers and lemon-grasses within 4 and 3 days, respectively. The products being dried in the dryer were completely protected from rains and insects and the dried products are of high quality. The solar air heater has an average daily efficiency of 35% and it performs well both as a solar collector and a roof of a farmhouse. (author)

  12. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    Science.gov (United States)

    Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  13. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    Directory of Open Access Journals (Sweden)

    Guo-Liang Xu

    Full Text Available Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm increased, but the percentage of large mites (body length >0.40 mm decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  14. Seasonal Exposure to Drought and Air Warming Affects Soil Collembola and Mites

    Science.gov (United States)

    Xu, Guo-Liang; Kuster, Thomas M.; Günthardt-Goerg, Madeleine S.; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4°C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type. PMID:22905210

  15. Soil-based filtration technology for air purification: potentials for environmental and space life support application

    Science.gov (United States)

    Nelson, Mark; Bohn, Hinrich

    Soil biofiltration, also known as Soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and seen numerous improvements, for example, by the use of high-organic compost beds to maximize microbial processes. This paper reviews the basic mechanisms which underlay soil processes involved in air purification, advantages and limitations of the technology and the cur-rent research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. SBR technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with air pumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop produc-tion, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, improvement of industrial air emissions and prevention of accidental release of toxic gases.

  16. Do Reductions in Dry Season Transpiration Allow Shallow Soil Water Uptake to Persist in a Tropical Lower Montane Cloud Forest?

    Science.gov (United States)

    Munoz Villers, L. E.; Holwerda, F.; Alvarado-Barrientos, M. S.; Goldsmith, G. R.; Geissert Kientz, D. R.; González Martínez, T. M.; Dawson, T. E.

    2016-12-01

    Tropical montane cloud forests (TMCF) are ecosystems particularly sensitive to climate change; however, the effects of warmer and drier conditions on TMCF water cycling remain poorly understood. To investigate the plant functional response to reduced water availability, we conducted a study during the mid to late dry season (2014) in the lower limit (1,325 m asl) of the TMCF belt (1200-2500 m asl) in central Veracruz, Mexico. The temporal variation of transpiration rates of dominant upper canopy and mid-story tree species, depth of water uptake, as well as tree water sources were examined using micrometeorological, sapflow and soil moisture measurements, in combination with data on stable isotope (δ18O and δ2H) composition of rain, tree xylem, soil (bulk and low suction-lysimeter) and stream water. The sapflow data suggest that crown conductances decreased as temperature and vapor pressure deficit increased, and soil moisture decreased from the mid to late dry season. Across all samplings (January 21, April 12 and 26), upper canopy species (Quercus spp.) showed more depleted (negative) isotope values compared to mid-story trees (Carpinus tropicalis). Overall, we found that the evaporated soil water pool was the main source for the trees. Furthermore, our MixSIAR Bayesian mixing model results showed that the depth of tree water uptake changed over the course of the dry season. Unexpectedly, a shift in water uptake from deeper (60-120 cm depth) to shallower soil water (0-30 cm) sources was observed, coinciding with the decreases in transpiration rates towards the end of the dry season. A larger reduction in deep soil water contributions was observed for upper canopy trees (from 70±14 to 22±15%) than for mid-story species (from 10±13 to 7±10%). The use of shallow soil water by trees during the dry season seems consistent with the greater root biomass and higher macronutrient concentrations found in the first 10 cm of the soil profiles. These findings are an

  17. Effects of human trampling on populations of soil fauna in the McMurdo Dry Valleys, Antarctica.

    Science.gov (United States)

    Ayres, Edward; Nkem, Johnson N; Wall, Diana H; Adams, Byron J; Barrett, J E; Broos, Emma J; Parsons, Andrew N; Powers, Laura E; Simmons, Breana L; Virginia, Ross A

    2008-12-01

    Antarctic ecosystems are often considered nearly pristine because levels of anthropogenic disturbance are extremely low there. Nevertheless, over recent decades there has been a rapid increase in the number of people, researchers and tourists, visiting Antarctica. We evaluated, over 10 years, the direct impact of foot traffic on the abundance of soil animals and soil properties in Taylor Valley within the McMurdo Dry Valleys region of Antarctica. We compared soils from minimally disturbed areas with soils from nearby paths that received intermediate and high levels of human foot traffic (i.e., up to approximately 80 passes per year). The nematodes Scottnema lindsayae and Eudorylaimus sp. were the most commonly found animal species, whereas rotifers and tardigrades were found only occasionally. On the highly trampled footpaths, abundance of S. lindsayae and Eudorylaimus sp. was up to 52 and 76% lower, respectively, than in untrampled areas. Moreover, reduction in S. lindsayae abundance was more pronounced after 10 years than 2 years and in the surface soil than in the deeper soil, presumably because of the longer period of disturbance and the greater level of physical disturbance experienced by the surface soil. The ratio of living to dead Eudorylaimus sp. also declined with increased trampling intensity, which is indicative of increased mortality or reduced fecundity. At one site there was evidence that high levels of trampling reduced soil CO(2) fluxes, which is related to total biological activity in the soil. Our results show that even low levels of human traffic can significantly affect soil biota in this ecosystem and may alter ecosystem processes, such as carbon cycling. Consequently, management and conservation plans for Antarctic soils should consider the high sensitivity of soil fauna to physical disturbance as human presence in this ecosystem increases.

  18. Induction of genetic changes in Saccharomyces cerevisiae by partial drying in air of constant relative humidity and by UV

    International Nuclear Information System (INIS)

    Hieda, K.

    1981-01-01

    It was investigated whether there was a critical degree of dryness for induction of genetic changes by drying. Saccharomyces cerevisiae cells were dried in air of 0.33, 53 and 76% relative humidity (RH). The frequencies of mitotic recombination at ade2, of gene conversion at leu1, and of gene mutation at can1 were measured in X2447, XS1473 and S288C strains, respectively. After the cells had been dried at 0% RH for 4 h the frequencies of the genetic changes at ade2, leu1 and can1 were, respectively, 56, 7 and 3.5 times higher than each spontaneous frequency. Induction rates, defined as the frequencies of the induced genetic changes per unit time (1 h) of drying, were greatly decreased with increase in RH. Partial drying in air of 76% RH up to 4 and 8 h induced no genetic change at ade2 and leu1, respectively. It was concluded, therefore, that drying at a certain RH between 53 and 76% gave the critical degreee of dryness of cells for the induction of the genetic changes. The water contents of cells (g water per g dry material) were 12% at 53% RH and 21% at 76% RH, whereas the water content of native cells was 212%. Removal of a large amount of cellular water had no effect on the induction of the genetic changes. UV sensitivity of partially dried cells of X2447 for the induction of the genetic change at ade2 drastically increased with decrease in RH between 76 and 53%. The drastic change in the UV sensitivity suggested that photochemical reactivity of DNA of chromosome XV, in which the ade2 locus is located, changed between 76 and 53% RH. It seems that the genetic changes were induced only in the low RH region where DNA in vivo had a different photochemical reactivity. (orig.)

  19. Radioactivity in soil and air near the Sillamaee tailings depository

    International Nuclear Information System (INIS)

    Realo, E.

    2002-01-01

    Radiological situation outside the Sillamaee plant and U/Th tailings depository is studied by soil monitoring and modelling methods. In the Sillamaee region, the reliable monitoring and assessment of the technological impact to public exposure is significantly interfered with the complex nature of natural background (e.g., elevated and variable soil concentrations of 226 Ra in the range of 40 .. 320 Bq kg -1 , high outdoor 222 Rn levels, etc.). The releases of radionuclides from the tailing depository to the ground and tap water are negligible. The major water pathway is the release to the Gulf of Finland and specifically the consumption of fish. The isotopes 234 U, 238 U (about 6.2 GBq a -1 or 0.025 % of the total U per year) and 210 Pb (∼ 0.05 GBq a -1 ) dominate in the source term. A compartmental modelling of this pathway has demonstrated a low radiological impact to the population with the individual and collective committed doses of 1 μSv and 1 manSv, respectively, for both current leakage and sudden dam collapse scenarios. We have determined the depth distribution of radionuclides in soil profiles to find an evidence for airborne radionuclide deposition. Samples collected in the Sillamaee town (up to 1 .. 2 km from the depository) have been analysed by using low background Ge(Li) and HPGe gamma spectrometry. The results demonstrate an enhanced (relative to the bottom layers) 226 Ra and 238 U content in the surface soil layers. A similar observation has been found near the oil-shale-fired power plants in NE Estonia, which we attributed to the long term deposition of fly-ash radionuclides. It should be noted that in the non-polluted locations over Estonia the 226 Ra concentration in the uppermost 0 .. 3 cm layer is about 11 % less than in the next 3 cm thick soil layers. In the ground level air, the mean dust loads of 0.23 mg m -3 (0.02 to 1.6 mg m -3 ) have been measured (V. Nossov, SILMET, 1997, private communication and [6]) with the aerosol beta

  20. Influence of prevailing disturbances on soil biology and biochemistry of montane habitats at Nanda Devi Biosphere Reserve, India during wet and dry seasons

    DEFF Research Database (Denmark)

    Singh, S.K.; Singh, Anoop; Rai, J.P.N.

    2011-01-01

    The impact of prevailing disturbances in montane habitats of Nanda Devi Biosphere Reserve (NDBR) was studied on soil microbial population, biomass, soil respiration and enzyme activities during wet and dry seasons. The physico-chemical characteristics of soils exhibited conspicuous variation in t...

  1. Nuclear thermal source transfer unit, post-blast soil sample drying system

    International Nuclear Information System (INIS)

    Wiser, Ralph S.; Valencia, Matthew J

    2017-01-01

    Los Alamos National Laboratory states that its mission is ''To solve national security challenges through scientific excellence.'' The Science Undergraduate Laboratory Internship (SULI) programs exists to engage undergraduate students in STEM work by providing opportunity to work at DOE facilities. As an undergraduate mechanical engineering intern under the SULI program at Los Alamos during the fall semester of 2016, I had the opportunity to contribute to the mission of the Laboratory while developing skills in a STEM discipline. I worked with Technology Applications, an engineering group that supports non-proliferation, counter terrorism, and emergency response missions. This group specializes in tool design, weapons engineering, rapid prototyping, and mission training. I assisted with two major projects during my appointment Los Alamos. The first was a thermal source transportation unit, intended to safely contain a nuclear thermal source during transit. The second was a soil drying unit for use in nuclear postblast field sample collection. These projects have given me invaluable experience working alongside a team of professional engineers. Skills developed include modeling, simulation, group design, product and system design, and product testing.

  2. Physiological genomics of response to soil drying in diverse Arabidopsis accessions.

    Science.gov (United States)

    Des Marais, David L; McKay, John K; Richards, James H; Sen, Saunak; Wayne, Tierney; Juenger, Thomas E

    2012-03-01

    Arabidopsis thaliana, like many species, is characterized by abundant genetic variation. This variation is rapidly being cataloged at the sequence level, but careful dissection of genetic variation in whole-organism responses to stresses encountered in the natural environment are lacking; this functional variation can be exploited as a natural mutant screen to determine gene function. Here, we document physiological and transcriptomic response to soil drying in 17 natural accessions of Arabidopsis. By imposing ecologically realistic stress conditions, we found that acclimation in Arabidopsis involved a strong signature of increased investment in photosynthesis, carbohydrate turnover, and root growth. Our results extend previous work in the Columbia accession suggesting that abscisic acid signaling pathways play an important role in drought stress response. We also identified several mechanisms, including an increase in leaf nitrogen concentration and upregulation of two-component signaling relays, that were common to most natural accessions but had not been identified in studies using only the Columbia accession. Principal component analysis reveals strong correlations between suites of genes and specific physiological responses to stress. The functional variants we identified may represent adaptive mutations in natural habitats and useful variants for agronomic improvement of crop species.

  3. Nuclear thermal source transfer unit, post-blast soil sample drying system

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ralph S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Valencia, Matthew J [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-03

    Los Alamos National Laboratory states that its mission is “To solve national security challenges through scientific excellence.” The Science Undergraduate Laboratory Internship (SULI) programs exists to engage undergraduate students in STEM work by providing opportunity to work at DOE facilities. As an undergraduate mechanical engineering intern under the SULI program at Los Alamos during the fall semester of 2016, I had the opportunity to contribute to the mission of the Laboratory while developing skills in a STEM discipline. I worked with Technology Applications, an engineering group that supports non-proliferation, counter terrorism, and emergency response missions. This group specializes in tool design, weapons engineering, rapid prototyping, and mission training. I assisted with two major projects during my appointment Los Alamos. The first was a thermal source transportation unit, intended to safely contain a nuclear thermal source during transit. The second was a soil drying unit for use in nuclear postblast field sample collection. These projects have given me invaluable experience working alongside a team of professional engineers. Skills developed include modeling, simulation, group design, product and system design, and product testing.

  4. Groundwater contamination by chlorinated hydrocarbons in the soil vapour phase - risk assessment at a former dry cleaner site

    Energy Technology Data Exchange (ETDEWEB)

    Danzer, J. [Boden-und-Grundwasser GbR, Sonthofen (Germany)

    2002-07-01

    Chlorinated hydrocarbons, e.g. Perchloroethene (PCE) were commonly used for dry cleaning purposes among other ones. Since they have a significant toxic potential they impose a serious risk to groundwater quality. Due to their physico-chemical properties - particularly high volatility and medium to high water solubility - and their low biodegradation potential they are highly mobile within the unsaturated soil (vapour phase) as well as within the groundwater. This poster (paper) presents data and calculations of a consultant's ''virtual every day'' work in order to assess the risk of groundwater contamination at a former dry cleaner site. (orig.)

  5. Seasonal dynamics of CO2 efflux in soils amended with composted and thermally-dried sludge as affected by soil tillage systems in a semi-arid agroecosystem

    Science.gov (United States)

    García-Gil, Juan Carlos; Soler-Rovira, Pedro; López-de-Sa, Esther G.; Polo, Alfredo

    2014-05-01

    In semi-arid agricultural soils, seasonal dynamic of soil CO2 efflux (SCE) is highly variable. Based on soil respiration measurements the effects of different management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) was investigated in a long-term field experiment (28 years) conducted on a sandy-loam soil at the experimental station 'La Higueruela' (40o 03'N, 4o 24'W). Both organic amendments were applied at a rate of 30 Mg ha-1 prior to tillage practices. Unamended soils were used as control for each tillage system. SCE was moderate in late spring (2.2-11.8 μmol CO2 m-2 s-1) when amendments were applied and tillage was performed, markedly decreased in summer (0.4-3.2 μmol CO2 m-2 s-1), following a moderate increase in autumn (3.4-14.1 μmol CO2 m-2 s-1), rising sharply in October (5.6-39.8 μmol CO2 m-2 s-1 ). In winter, SCE was low (0.6-6.5 μmol CO2 m-2 s-1). In general, SCE was greater in chisel and moldboard tilled soils, and in CS and particularly TSS-amended soils, due to the addition of labile C with these amendments, meanwhile no-tillage soils exhibited smaller increases in C efflux throughout the seasons. Soil temperature controlled the seasonal variations of SCE. In summer, when drought occurs, a general decrease of SCE was observed due to a deficit in soil water content. After drought period SCE jumped to high values in response to rain events ('Birch effect') that changed soil moisture conditions. Soil drying in summer and rewetting in autumn may promotes some changes on the structure of soil microbial community, affecting associated metabolic processes, and enhancing a rapid mineralization of water-soluble organic C compounds and/or dead microbial biomass that acts as an energy source for soil microorganisms. To assess the effects of tillage and amendments on SCE, Q10 values were calculated. Data were grouped into three groups according to soil moisture (0

  6. Influence of operating conditions on the air gasification of dry refinery sludge in updraft gasifier

    International Nuclear Information System (INIS)

    Ahmed, R; Sinnathambi, C M

    2013-01-01

    In the present work, details of the equilibrium modeling of dry refinery sludge (DRS) are presented using ASPEN PLUS Simulator in updraft gasifier. Due to lack of available information in the open journal on refinery sludge gasification using updraft gasifier, an evaluate for its optimum conditions on gasification is presented in this paper. For this purpose a Taguchi Orthogonal array design, statistical software is applied to find optimum conditions for DRS gasification. The goal is to identify the most significant process variable in DRS gasification conditions. The process variables include; oxidation zone temperature, equivalent ratio, operating pressure will be simulated and examined. Attention was focused on the effect of optimum operating conditions on the gas composition of H 2 and CO (desirable) and CO 2 (undesirable) in terms of mass fraction. From our results and finding it can be concluded that the syngas (H 2 and CO) yield in term of mass fraction favors high oxidation zone temperature and at atmospheric pressure while CO 2 acid gas favor at a high level of equivalent ratio as well as air flow rate favoring towards complete combustion.

  7. Remediation of muddy tidal flat sediments using hot air-dried crushed oyster shells.

    Science.gov (United States)

    Yamamoto, Tamiji; Kondo, Shunsuke; Kim, Kyung-Hoi; Asaoka, Satoshi; Yamamoto, Hironori; Tokuoka, Makoto; Hibino, Tadashi

    2012-11-01

    In order to prove that hot air-dried crushed oyster shells (HACOS) are effective in reducing hydrogen sulfide in muddy tidal flat sediments and increasing the biomass, field experiments were carried out. The concentration of hydrogen sulfide in the interstitial water, which was 16 mg SL(-1) before the application of HACOS, decreased sharply and maintained almost zero in the experimental sites (HACOS application sites) for one year, whereas it was remained at ca. 5 mg SL(-1) in the control sites. The number of macrobenthos individuals increased to 2-4.5 times higher than that in the control site. Using a simple numerical model, the effective periods for suppression of hydrogen sulfide were estimated to be 3.2-7.6 and 6.4-15.2 years for the experimental sites with 4 and 8 tons per 10 × 10 × 0.2m area, respectively. From these results, it is concluded that HACOS is an effective material to remediate muddy tidal flats. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Microparticle charging in dry air plasma created by an external ionization source

    International Nuclear Information System (INIS)

    Derbenev, I N; Filippov, A V

    2015-01-01

    In the present paper the dust particle charging is studied in a dry air plasma created by an external ionization source. The ionization rate is changed in the range 10 1 -10 20 cm -3 s -1 . It is found that the main positive ion of the plasma is O + 4 and the main negative ones are O − 2 and O − 4 . The point sink model based on the diffusion-drift approach shows that the screening potential distribution around a dust particle is a superposition of four Debye-like exponentials with four different spatial scales. The first scale almost coincides with the Debye radius. The second one is the distance, passed by positive and negative plasma components due to ambipolar diffusion in their recombination time. The third one is defined by the negative ion conversion and diffusion. The fourth scale is described by the electron attachment, recombination and diffusion at low gas ionization rates and by the recombination and diffusion of negative diatomic ions at high ionization rates. It is also shown that the electron flux defines the microparticle charge at high ionization rates, whereas the electron number density is much less than the ion one. (paper)

  9. Final report on CCQM-P151: Halocarbons in dry whole air

    Science.gov (United States)

    Rhoderick, George; Guenther, Franklin; Duewer, David; Lee, Jeongsoon; Seog Kim, Jin; Hall, Bradley; Weiss, Ray; Harth, Christina; Reimann, Stefan; Vollmer, Martin

    2014-01-01

    The growing awareness of climate change/global warming and continuing concerns regarding stratospheric ozone depletion will require future measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track and control the emissions of these species globally in the atmosphere, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. This report describes the results of a pilot study between National Metrology Institutes and atmospheric research laboratories for several of the more important halocarbons at atmospheric concentration levels. The comparison includes the chlorofluorocarbons (CFCs) dichlorodifluoromethane (CFC 12), trichlorofluoromethane (CFC 11), and 1,1,2-trichlorotrifluoroethane (CFC 113); the hydrochlorofluorocarbons (HCFCs) chlorodifluoromethane (HCFC 22) and 1-chloro-1,1-difluoroethane (HCFC 142b); and the hydrofluorocarbon (HFC) 1,1,1,2-tetrafluoroethane (HFC 134a), all in a dried whole air sample. The objective of this key comparison is to compare the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM.

  10. Comparison of halocarbon measurements in an atmospheric dry whole air sample.

    Science.gov (United States)

    Rhoderick, George C; Hall, Bradley D; Harth, Christina M; Kim, Jin Seog; Lee, Jeongsoon; Montzka, Stephen A; Mühle, Jens; Reimann, Stefan; Vollmer, Martin K; Weiss, Ray F

    The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance. A common source of standards/scales and/or well-documented agreement of different scales used to calibrate the measurement instrumentation are key to understanding many sets of data reported by researchers. This report describes the results of a comparison study among National Metrology Institutes and atmospheric research laboratories for the chlorofluorocarbons (CFCs) dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), and 1,1,2-trichlorotrifluoroethane (CFC-113); the hydrochlorofluorocarbons (HCFCs) chlorodifluoromethane (HCFC-22) and 1-chloro-1,1-difluoroethane (HCFC-142b); and the hydrofluorocarbon (HFC) 1,1,1,2-tetrafluoroethane (HFC-134a), all in a dried whole air sample. The objective of this study is to compare calibration standards/scales and the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. The results of this study show agreement among four independent calibration scales to better than 2.5% in almost all cases, with many of the reported agreements being better than 1.0%.

  11. Final report on international comparison CCQM-K83: Halocarbons in dry whole air

    Science.gov (United States)

    Rhoderick, George; Guenther, Franklin; Duewer, David; Lee, Jeongsoon; Moon, Dongmin; Lee, Jinbok; Lim, Jeongsik; Seog Kim, Jin

    2014-01-01

    The growing awareness of climate change/global warming and continuing concerns regarding stratospheric ozone depletion will require future measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track and control the emissions of these species globally in the atmosphere, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. This report describes the results of a key comparison for several of the more important halocarbons at atmospheric concentration levels. The comparison includes the chlorofluorocarbons (CFCs) dichlorodifluoromethane (CFC 12), trichlorofluoromethane (CFC 11), and 1,1,2 trichlorotrifluoroethane (CFC 113); the hydrochlorofluorocarbons (HCFCs) chlorodifluoromethane (HCFC 22) and 1-chloro-1,1-difluoroethane (HCFC 142b); and the hydrofluorocarbon (HFC) 1,1,1,2 tetrafluoroethane (HFC 134a), all in a dried whole air sample. The objective of this key comparison is to compare the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Comparison of halocarbon measurements in an atmospheric dry whole air sample

    Directory of Open Access Journals (Sweden)

    George C. Rhoderick

    2015-11-01

    Full Text Available Abstract The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance. A common source of standards/scales and/or well-documented agreement of different scales used to calibrate the measurement instrumentation are key to understanding many sets of data reported by researchers. This report describes the results of a comparison study among National Metrology Institutes and atmospheric research laboratories for the chlorofluorocarbons (CFCs dichlorodifluoromethane (CFC-12, trichlorofluoromethane (CFC-11, and 1,1,2-trichlorotrifluoroethane (CFC-113; the hydrochlorofluorocarbons (HCFCs chlorodifluoromethane (HCFC-22 and 1-chloro-1,1-difluoroethane (HCFC-142b; and the hydrofluorocarbon (HFC 1,1,1,2-tetrafluoroethane (HFC-134a, all in a dried whole air sample. The objective of this study is to compare calibration standards/scales and the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. The results of this study show agreement among four independent calibration scales to better than 2.5% in almost all cases, with many of the reported agreements being better than 1.0%.

  13. Co-combustion of low rank coal/waste biomass blends using dry air or oxygen

    International Nuclear Information System (INIS)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S.

    2013-01-01

    Biomass species such as the rice husk and the olive milling residue, and a low quality Turkish coal, Soma Denis lignite, were burned in a thermal analyzer under pure oxygen and dry air up to 900 °C, and differential thermal analysis (DTA) and derivative thermogravimetric (DTG) analysis profiles were obtained. Co-combustion experiments of lignite/biomass blends containing 5–20 wt% of biomass were also performed. The effects of the oxidizer type and the blending ratio of biomass were evaluated considering some thermal reactivity indicators such as the maximum burning rate and its temperature, the maximum heat flow temperature, and the burnout levels. FTIR (Fourier transform infrared) spectroscopy and SEM (scanning electron microscopy) were used to characterize the samples, and the variations in the combustion characteristics of the samples were interpreted based on the differences in the intrinsic properties of the samples. - Highlights: ► Co-combustion of lignite/biomass blends. ► The effects of the oxidizer type and the blending ratio. ► Effects of intrinsic properties on combustion characteristics.

  14. Comparison of halocarbon measurements in an atmospheric dry whole air sample

    Science.gov (United States)

    Hall, Bradley D.; Harth, Christina M.; Kim, Jin Seog; Lee, Jeongsoon; Montzka, Stephen A.; Mühle, Jens; Reimann, Stefan; Vollmer, Martin K.; Weiss, Ray F.

    2015-01-01

    The growing awareness of climate change/global warming, and continuing concerns regarding stratospheric ozone depletion, will require continued measurements and standards for many compounds, in particular halocarbons that are linked to these issues. In order to track atmospheric mole fractions and assess the impact of policy on emission rates, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards. Precise measurements of these species aid in determining small changes in their atmospheric abundance. A common source of standards/scales and/or well-documented agreement of different scales used to calibrate the measurement instrumentation are key to understanding many sets of data reported by researchers. This report describes the results of a comparison study among National Metrology Institutes and atmospheric research laboratories for the chlorofluorocarbons (CFCs) dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), and 1,1,2-trichlorotrifluoroethane (CFC-113); the hydrochlorofluorocarbons (HCFCs) chlorodifluoromethane (HCFC-22) and 1-chloro-1,1-difluoroethane (HCFC-142b); and the hydrofluorocarbon (HFC) 1,1,1,2-tetrafluoroethane (HFC-134a), all in a dried whole air sample. The objective of this study is to compare calibration standards/scales and the measurement capabilities of the participants for these halocarbons at trace atmospheric levels. The results of this study show agreement among four independent calibration scales to better than 2.5% in almost all cases, with many of the reported agreements being better than 1.0%. PMID:26753167

  15. [Influence of Different Straws Returning with Landfill on Soil Microbial Community Structure Under Dry and Water Farming].

    Science.gov (United States)

    Lan, Mu-ling; Gao, Ming

    2015-11-01

    Based on rice, wheat, corn straw and rape, broad bean green stalk as the research object, using phospholipid fatty acid (PLFA) method, combining principal component analysis method to study the soil microbial quantity, distribution of flora, community structure characteristics under dry and water farming as two different cultivated land use types. The PLFA analysis results showed that: under dry farming, total PLFA quantity ranged 8.35-25.15 nmol x g(-1), showed rape > broad bean > corn > rice > wheat, rape and broad bean significantly increased total PLFA quantity by 1.18 and 1.08 times compared to the treatment without straw; PLFA quantity of bacterial flora in treatments with straws was higher than that without straw, and fungal biomass was significantly increased, so was the species richness of microbial community. Under water faming, the treatments of different straws returning with landfill have improved the PLFA quantity of total soil microbial and flora comparing with the treatment without straw, fungi significantly increased, and species richness of microbial communities value also increased significantly. Total PLFA quantity ranged 4.04-22.19 nmol x g(-1), showed rice > corn > wheat > broad bean > rape, which in rape and broad bean treatments were lower than the treatment without straw; fungal PLFA amount in 5 kinds of straw except broad bean treatment was significantly higher than that of the treatment without straw, bacteria and total PLFA quantity in broad bean processing were significantly lower than those of other treatments, actinomycetes, G+, G- had no significant difference between all treatments; rice, wheat, corn, rape could significantly increase the soil microbial species richness index and dominance index under water faming. The results of principal component analysis showed that broad bean green stalk had the greatest impact on the microbial community structure in the dry soil, rape green stalk and wheat straw had the biggest influence on

  16. Green Remediation Best Management Practices: Soil Vapor Extraction & Air Sparging

    Science.gov (United States)

    Historically, approximately one-quarter of Superfund source control projects have involved soil vapor extraction (SVE) to remove volatile organic compounds (VOCs) sorbed to soil in the unsaturated (vadose) zone.

  17. Dry flue gas desulfurization by-product application effects on plant uptake and soil storage changes in a managed grassland.

    Science.gov (United States)

    Burgess-Conforti, Jason R; Brye, Kristofor R; Miller, David M; Pollock, Erik D; Wood, Lisa S

    2018-02-01

    Environmental regulations mandate that sulfur dioxide (SO 2 ) be removed from the flue gases of coal-fired power plants, which results in the generation of flue gas desulfurization (FGD) by-products. These FGD by-products may be a viable soil amendment, but the large amounts of trace elements contained in FGD by-products are potentially concerning. The objective of this study was to evaluate the effects of land application of a high-Ca dry FGD (DFGD) by-product on trace elements in aboveground biomass and soil. A high-Ca DFGD by-product was applied once at a rate of 9 Mg ha -1 on May 18, 2015 to small plots with mixed-grass vegetation. Soil and biomass were sampled prior to application and several times thereafter. Aboveground dry matter and tissue As, Co, Cr, Hg, Se, U, and V concentrations increased (P  0.05) from pre-application levels or the unamended control within 3 to 6 months of application. Soil pH in the amended treatment 6 months after application was greater (P by-product application compared to the unamended control. High-Ca DFGD by-products appear to be useful as a soil amendment, but cause at least a temporary increase in tissue concentrations of trace elements, which may be problematic for animal grazing situations.

  18. A measurement of summertime dry deposition of ambient air particulates and associated metallic pollutants in Central Taiwan.

    Science.gov (United States)

    Fang, Guor-Cheng; Chiang, Hung-Che; Chen, Yu-Cheng; Xiao, You-Fu; Wu, Chia-Ming; Kuo, Yu-Chen

    2015-04-01

    The purpose of this study is to characterize metallic elements associated with atmospheric particulate matter in the dry deposition plate, total suspended particulate, fine particles, and coarse particles at Taichung Harbor and Gong Ming Junior High School (airport) in central Taiwan at a sampling site from June 2013 to August 2013. The results indicated that: (1) the average concentrations of the metallic elements Cr and Cd were highest at the Gong Ming Junior High School (airport), and the average concentrations of the metallic elements Ni, Cu, and Pb were highest at the Taichung Harbor sampling site. (2) The high smelting industry density and export/import rate of heavily loaded cargos were the main reasons leading to these findings. (3) The average metallic element dry deposition and metallic element PM(2.5-10) all followed the order of Pb > Cr > Cu > Ni > Cd at the two sampling sites. However, the average metallic elements Cu and Pb were found to have the highest dry deposition velocities and concentrations in PM(2.5) for the two sampling sites in this study. (4) The correlation coefficients of ambient air particle dry deposition and concentration with wind speed at the airport were higher than those from the harbor sampling site. The wind and broad open spaces at Taichung Airport were the possible reasons for the increasing correlation coefficients for ambient air particle concentration and dry deposition with wind speed at the Taichung Airport sampling site.

  19. Shrinkage and porosity evolution during air-drying of non-cellular food systems: Experimental data versus mathematical modelling.

    Science.gov (United States)

    Nguyen, Thanh Khuong; Khalloufi, Seddik; Mondor, Martin; Ratti, Cristina

    2018-01-01

    In the present work, the impact of glass transition on shrinkage of non-cellular food systems (NCFS) during air-drying will be assessed from experimental data and the interpretation of a 'shrinkage' function involved in a mathematical model. Two NCFS made from a mixture of water/maltodextrin/agar (w/w/w: 1/0.15/0.015) were created out of maltodextrins with dextrose equivalent 19 (MD19) or 36 (MD36). The NCFS made with MD19 had 30°C higher Tg than those with MD36. This information indicated that, during drying, the NCFS with MD19 would pass from rubbery to glassy state sooner than NCFS MD36, for which glass transition only happens close to the end of drying. For the two NCFS, porosity and volume reduction as a function of moisture content were captured with high accuracy when represented by the mathematical models previously developed. No significant differences in porosity and in maximum shrinkage between both samples during drying were observed. As well, no change in the slope of the shrinkage curve as a function of moisture content was perceived. These results indicate that glass transition alone is not a determinant factor in changes of porosity or volume during air-drying. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Numerical characterisation of one-step and three-step solar air heating collectors used for cocoa bean solar drying.

    Science.gov (United States)

    Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel; La Madrid, Raúl

    2017-12-01

    In the northern coastal and jungle areas of Peru, cocoa beans are dried using artisan methods, such as direct exposure to sunlight. This traditional process is time intensive, leading to a reduction in productivity and, therefore, delays in delivery times. The present study was intended to numerically characterise the thermal behaviour of three configurations of solar air heating collectors in order to determine which demonstrated the best thermal performance under several controlled operating conditions. For this purpose, a computational fluid dynamics model was developed to describe the simultaneous convective and radiative heat transfer phenomena under several operation conditions. The constructed computational fluid dynamics model was firstly validated through comparison with the data measurements of a one-step solar air heating collector. We then simulated two further three-step solar air heating collectors in order to identify which demonstrated the best thermal performance in terms of outlet air temperature and thermal efficiency. The numerical results show that under the same solar irradiation area of exposition and operating conditions, the three-step solar air heating collector with the collector plate mounted between the second and third channels was 67% more thermally efficient compared to the one-step solar air heating collector. This is because the air exposition with the surface of the collector plate for the three-step solar air heating collector former device was twice than the one-step solar air heating collector. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of production methods and protective ingredients on the viability of probiotic Lactobacillus rhamnosus R0011 in air-dried alginate beads.

    Science.gov (United States)

    Champagne, Claude P; Raymond, Yves; Arcand, Yves

    2017-01-01

    The goal of this study was to use a microencapsulation technology to prepare air-dried concentrated cultures of Lactobacillus rhamnosus R0011. The cultures were microencapsulated in alginate beads, which were added to a growth medium to allow cell multiplication inside the matrix; the beads were recovered, dipped in protective solutions, and air-dried. The effects of fermentation technology and of the composition of the protective solutions on subsequent survival during air-drying were examined. The cells prepared under a constant pH of 6.2 had only 2.5% survival to air-drying at 25 °C when the protective solution was composed of sucrose and phosphate. Allowing the pH to drop to 4.2 during the biomass production step and using a protective medium composed of glycerol, maltodextrin, yeast extract, and ascorbate increased survival to 20%. If the ingredients of the protective medium at the beginning of drying were concentrated at a water activity of 0.96 rather than 0.98, survival during air-drying increased further to 56%. This rate was similar to that of a traditional freeze-drying process. These data suggest that applying a combination of acid and osmotic stresses to L. rhamnosus R0011 cells improves their subsequent stability during the air-drying process. Dried microencapsulated cultures having 2.6 × 10 11 CFU·g -1 were obtained.

  2. Bench-scale feasibility testing of pulsed-air technology for in-tank mixing of dry cementitious solids with tank liquids and settled solids

    International Nuclear Information System (INIS)

    Whyatt, G.A.; Hymas, C.R.

    1997-09-01

    This report documents the results of testing performed to determine the feasibility of using a pulsed-air mixing technology (equipment developed by Pulsair Systems, Inc., Bellevue, WA) to mix cementitious dry solids with supernatant and settled solids within a horizontal tank. The mixing technology is being considered to provide in situ stabilization of the open-quotes Vclose quotes tanks at the Idaho National Engineering and Environmental Laboratory (INEEL). The testing was performed in a vessel roughly 1/6 the scale of the INEEL tanks. The tests used a fine soil to simulate settled solids and water to simulate tank supernatants. The cementitious dry materials consisted of Portland cement and Aquaset-2H (a product of Fluid Tech Inc. consisting of clay and Portland cement). Two scoping tests were conducted to allow suitable mixing parameters to be selected. The scoping tests used only visual observations during grout disassembly to assess mixing performance. After the scoping tests indicated the approach may be feasible, an additional two mixing tests were conducted. In addition to visual observations during disassembly of the solidified grout, these tests included addition of chemical tracers and chemical analysis of samples to determine the degree of mixing uniformity achieved. The final two mixing tests demonstrated that the pulsed-air mixing technique is capable of producing slurries containing substantially more cementitious dry solids than indicated by the formulations suggested by INEEL staff. Including additional cement in the formulation may have benefits in terms of increasing mobilization of solids, reducing water separation during curing, and increasing the strength of the solidified product. During addition to the tank, the cementitious solids had a tendency to form clumps which broke down with continued mixing

  3. The Influence of Different Air-Drying Conditions on Bioactive Compounds and Antioxidant Activity of Berries.

    Science.gov (United States)

    Bustos, Mariela C; Rocha-Parra, Diego; Sampedro, Ines; de Pascual-Teresa, Sonia; León, Alberto E

    2018-03-21

    The aim of the present research was to study the effect of convective drying on color, bioactive compounds, and antioxidant activity of berry fruits and to chemically characterize the polyphenolic composition of raspberry, boysenberry, redcurrants, and blackcurrants fruit. Drying berries at 65 °C provoked the best conservations of color, particularly for boysenberry and blackcurrant. Drying at 65 °C was also the condition that showed higher level of polyphenols, while drying at 50 or 130 °C showed above % degradation of them due to the long time or high temperature drying. Radical scavenging activity was the predominant antioxidant mechanism in all samples, with 65 °C dried berries being the most active ones possibly because of polyphenol depolymerization. The anthocyanin profile showed that delphinidin and cyanidin derivatives were the most abundant anthocyanidins with different predominance between berry genera. Degradation of anthocyanins was increased with drying temperature been Cy 3-glucoside and Cy 3-rutinoside the most abundant.

  4. 222Rn flux and soil air concentration profiles in West-Germany. Soil 222Rn as tracer for gas transport in the unsaturated soil zone

    International Nuclear Information System (INIS)

    Doerr, H.; Muennich, K.O.

    1990-01-01

    Measurements of the 222 Rn activity concentration profile in the soil and the 222 Rn flux in West-Germany are presented. The spatial pattern of the 222 Rn flux depends more on soil type than on the 226 Ra activity of the soil material. The average 222 Rn flux from sandy soils is 1000-2000 dpm m -2 h -1 and 4000-6000 dpm m -2 h -1 froam loamy and clayey soils. Weekly 222 Rn flux measurements during a period of 1 year at a sandy site show no significant temporal variations. At a clayey site, the 222 Rn flux tends to be higher in summer than in winter. The permeability coefficient P Rn , obtained from simultaneous 222 Rn flux and concentration profile measurements in various soils, can be expressed as a function of the soil parameters total porosity ε 0 , soil moisture F, tortuosity k and the molecular diffusion coefficient D 0 of 222 Rn in air: P = D 0 ((ε 0 -F)/k-const.). The flux of any other gas into or out of the soil can thus be calculated from its measured concentration profile in the soil and from the 222 Rn permeability coefficient, replacing the molecular diffusion coefficient of 222 Rn by that of the specific gas under consideration. As an example, this method of flux determination is demonstrated for the soil CO 2 flux to the atmosphere and for the flux of atmospheric CH 4 into the soil. (author) 14 refs

  5. Influence of diesel contamination in soil on growth and dry matter partitioning of Lactuca sativa and Ipomoea batatas.

    Science.gov (United States)

    Fatokun, Kayode; Zharare, Godfrey Elijah

    2015-09-01

    Phytotoxic effect of diesel contaminated soil was investigated on growth and dry matter partitioning in Lactuca sativa and Ipomoea batatas in greenhouse pot experiment at two concentration range (0-30 ml and 0-6 ml diesel kg(-1) soil) for 14 weeks. The results indicated thatwhole plant biomass, stem length, root length, number of leaves and leaf chlorophyll in two plants were negatively correlated with increasing diesel concentrations. The critical concentration of diesel associated with 10% decrease in plant growth was 0.33 ml for lettuce and 1.50 ml for sweet potato. Thus, growth of lettuce in diesel contaminated soil was more sensitive than sweet potato. The pattern of dry matter partitioning between root and shoot in both plants were similar. In 0-6 ml diesel contamination range, allocation of dry matter to shoot system was favoured resulting in high shoot: root ratio of 4.54 and 12.91 for lettuce and sweet potato respectively. However, in 0-30 ml diesel contamination range, allocation of dry matter to root was favoured, which may have been an adaptive mechanism in which the root system was used for storage in addition to increasing the capacity for foraging for mineral nutrients and water. Although lettuce accumulated more metals in its tissue than sweet potato, the tissue mineral nutrients in both species did not vary to great extent. The critical diesel concentration for toxicity suggested that the cause of mortality and poor growth of sweet potato and lettuce grown in diesel contaminated soil was due to presence of hydrocarbons in diesel.

  6. Application of a 2D air flow model to soil vapor extraction and bioventing case studies

    International Nuclear Information System (INIS)

    Mohr, D.H.; Merz, P.H.

    1995-01-01

    Soil vapor extraction (SVE) is frequently the technology of choice to clean up hydrocarbon contamination in unsaturated soil. A two-dimensional air flow model provides a practical tool to evaluate pilot test data and estimate remediation rates for soil vapor extraction systems. The model predictions of soil vacuum versus distance are statistically compared to pilot test data for 65 SVE wells at 44 sites. For 17 of 21 sites where there was asphalt paving, the best agreement was obtained for boundary conditions with no barrier to air flow at the surface. The model predictions of air flow rates and stream lines around the well allow an estimate of the gasoline removal rates by both evaporation and bioremediation. The model can be used to quickly estimate the effective radius of influence, defined here as the maximum distance from the well where there is enough air flow to remove the contaminant present within the allowable time. The effective radius of influence is smaller than a radius of influence defined by soil vacuum only. For a case study, in situ bioremediation rates were estimated using the air flow model and compared to independent estimates based on changes in soil temperature. These estimate bioremediation rates for heavy fuel oil ranged from 2.5 to 11 mg oil degraded per kg soil per day, in agreement with values in the literature

  7. Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems.

    Science.gov (United States)

    Campo, Julio; Merino, Agustín

    2016-05-01

    The effect of precipitation regime on the C cycle of tropical forests is poorly understood, despite the existence of models that suggest a drier climate may substantially alter the source-sink function of these ecosystems. Along a precipitation regime gradient containing 12 mature seasonally dry tropical forests growing under otherwise similar conditions (similar annual temperature, rainfall seasonality, and geological substrate), we analyzed the influence of variation in annual precipitation (1240 to 642 mm) and duration of seasonal drought on soil C. We investigated litterfall, decomposition in the forest floor, and C storage in the mineral soil, and analyzed the dependence of these processes and pools on precipitation. Litterfall decreased slightly - about 10% - from stands with 1240 mm yr(-1) to those with 642 mm yr(-1), while the decomposition decreased by 56%. Reduced precipitation strongly affected C storage and basal respiration in the mineral soil. Higher soil C storage at the drier sites was also related to the higher chemical recalcitrance of litter (fine roots and forest floor) and the presence of charcoal across sites, suggesting an important indirect influence of climate on C sequestration. Basal respiration was controlled by the amount of recalcitrant organic matter in the mineral soil. We conclude that in these forest ecosystems, the long-term consequences of decreased precipitation would be an increase in organic layer and mineral soil C storage, mainly due to lower decomposition and higher chemical recalcitrance of organic matter, resulting from changes in litter composition and, likely also, wildfire patterns. This could turn these seasonally dry tropical forests into significant soil C sinks under the predicted longer drought periods if primary productivity is maintained. © 2016 John Wiley & Sons Ltd.

  8. Impacts of soil incorporation of pre-incubated silica-rich rice residue on soil biogeochemistry and greenhouse gas fluxes under flooding and drying.

    Science.gov (United States)

    Gutekunst, Madison Y; Vargas, Rodrigo; Seyfferth, Angelia L

    2017-09-01

    Incorporation of silica-rich rice husk residue into flooded paddy soil decreases arsenic uptake by rice. However, the impact of this practice on soil greenhouse gas (GHG) emissions and elemental cycling is unresolved particularly as amended soils experience recurrent flooding and drying cycles. We evaluated the impact of pre-incubated silica-rich rice residue incorporation to soils on pore water chemistry and soil GHG fluxes (i.e., CO 2 , CH 4 , N 2 O) over a flooding and drying cycle typical of flooded rice cultivation. Soils pre-incubated with rice husk had 4-fold higher pore water Si than control and 2-fold higher than soils pre-incubated with rice straw, whereas the pore water As and Fe concentrations in soils amended with pre-incubated straw and husk were unexpectedly similar (maximum ~0.85μM and ~450μM levels, respectively). Pre-incubation of residues did not affect Si but did affect the pore water levels of As and Fe compared to previous studies using fresh residues where straw amended soils had higher As and Fe in pore water. The global warming potential (GWP) of soil GHG emissions decreased in the order straw (612±76g CO 2 -eqm -2 )>husk (367±42gCO 2 -eqm -2 )>ashed husk=ashed straw (251±26 and 278±28gCO 2 -eqm -2 )>control (186±23gCO 2 -eqm -2 ). The GWP increase due to pre-incubated straw amendment was due to: a) larger N 2 O fluxes during re-flooding; b) smaller contributions from larger CH 4 fluxes during flooded periods; and c) higher CH 4 and CO 2 fluxes at the onset of drainage. In contrast, the GWP of the husk amendment was dominated by CO 2 and CH 4 emissions during flooded and drainage periods, while ashed amendments increased CO 2 emissions particularly during drainage. This experiment shows that ashed residues and husk addition minimizes GWP of flooded soils and enhances pore water Si compared to straw addition even after pre-incubation. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Air-side performance evaluation of three types of heat exchangers in dry, wet and periodic frosting conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ping [Zhejiang Vocational College of Commerce, Hangzhou, Binwen Road 470 (China); Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States); Hrnjak, P.S. [Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States)

    2009-08-15

    The performances of three types of heat exchangers that use the louver fin geometry: (1) parallel flow parallel fin with extruded flat tubes heat exchanger (PF{sup 2}), (2) parallel flow serpentine fin with extruded flat tubes heat exchanger (PFSF) and (3) round tube wave plate fin heat exchanger (RTPF) have been experimentally studied under dry, wet and frost conditions and results are presented. The parameters quantified include air-side pressure drop, water retention on the surface of the heat exchanger, capacity and overall heat transfer coefficient for air face velocity 0.9, 2 and 3 m/s, air humidity 70% and 80% and different orientations. The performances of three types of heat exchanger are compared and the results obtained are presented. The condensate drainage behavior of the air-side surface of these three heat exchanger types was studied using both the dip testing method and wind tunnel experiment. (author)

  10. Relative Efficacy of On-Farm Weeds as Soil-Amendement for Managing Dry Root Rot of Clusterbean in an Arid Environment

    Directory of Open Access Journals (Sweden)

    R. Mawar

    2006-12-01

    Full Text Available The effectiveness of certain on-farm weeds as soil amendments was ascertained against Macrophomina phaseolina, a soil-borne pathogen causing dry root rot of crops grown under rainfed conditions in arid regions. Population changes in M. phaseolina were determined in soils amended separately with residues (1%, w:w of Aerva persica, Celosia argentea, Corchorus depressus, Euphorbia hirta, Heliotropium subulatum and Polycarpaea corymbosa, for a period of 90 days. Significant reductions by 90.4–100% in the population of M. phaseolina were achieved with all the weed residues except P. corymbosa. Celosia and Euphorbia residues completely eradicated viable propagules of M. phaseolina. A strong increase (44–61% in the population of antagonistic actinomycetes was also found in soil amended with Corchorus and Euphorbia. In field tests, soil amended (50 g m2 with Euphorbia, Aerva and Celosia residues significantly reduced dry root rot incidence on clusterbean and also reduced M. phaseolina propagules in the soil. However, dry root rot incidence in Polycarpaea-amended soil (5.8–24.6% was not significantly different from that in non-amended soil (4.3–25.3% in both years of the experiment. P. corymbosa also increased the number of propagules of M. phaseolina in the soil. The results demonstrate that dry root rot of rainfed-cultivated annual crops in arid land can be managed with certain weeds as a soil amendment.

  11. Combined in-situ and ex-situ bioremediation of petroleum hydrocarbon contaminated soils by closed-loop soil vapor extraction and air injection

    International Nuclear Information System (INIS)

    Hu, S.S.; Buckler, M.J.

    1993-01-01

    Treatment and restoration of petroleum hydrocarbon contaminated soils at a bulk petroleum above-ground storage tank (AST) site in Michigan is being conducted through in-situ and ex-situ closed-loop soil vapor extraction (SVE), soil vapor treatment, and treated air injection (AI) processes. The soil vapor extraction process applies a vacuum through the petroleum hydrocarbon affected soils in the ex-situ bio-remediation pile (bio-pile) and along the perimeter of excavated area (in-situ area) to remove the volatile or light petroleum hydrocarbons. This process also draws ambient air into the ex-situ bio-pile and in-situ vadose zone soil along the perimeter of excavated area to enhance biodegradation of light and heavy petroleum hydrocarbons in the soil. The extracted soil vapor is treated using a custom-designed air bio-remediation filter (bio-filter) to degrade the petroleum hydrocarbon compounds in the soil vapor extraction air streams. The treated air is then injected into a flush grade soil bed in the backfill area to perform final polishing of the air stream, and to form a closed-loop air flow with the soil vapor extraction perforated pipes along the perimeter of the excavated area

  12. Numerical modelling of the effect of dry air traces in a helium parallel plate dielectric barrier discharge

    Science.gov (United States)

    Lazarou, C.; Belmonte, T.; Chiper, A. S.; Georghiou, G. E.

    2016-10-01

    A validated numerical model developed for the study of helium barrier discharges in the presence of dry air impurities is presented in this paper. The model was used to numerically investigate the influence of air traces on the evolution of the helium dielectric barrier discharge (DBD). The level of dry air used as impurity was in the range from 0 to 1500 ppm, which corresponds to the most commonly encountered range in atmospheric pressure discharge experiments. The results presented in this study clearly show that the plasma chemistry and consequently the discharge evolution is highly affected by the concentration level of impurities in the mixture. In particular, it was observed that air traces assist the discharge ignition at low concentration levels (~55 ppm), while on the other hand, they increase the burning voltage at higher concentration levels (~1000 ppm). Furthermore, it was found that the discharge symmetry during the voltage cycle highly depends on the concentration of air. For the interpretation of the results, a detailed analysis of the processes that occur in the discharge gap is performed and the main reaction pathways of ion production are described. Thanks to this approach, useful insight into the physics behind the evolution of the discharge is obtained.

  13. Influence of carbon monoxide additions on the sensitivity of the dry hydrogen-air mixtures to detonation

    International Nuclear Information System (INIS)

    Magzumov, A.E.; Kirillov, I.A.; Fridman, A.A.; Rusanov, V.D.

    1995-01-01

    Under severe accident conditions of water cooled nuclear reactors the hydrogen-air detonation represents one of the most hazardous events which can result in the reactor containment damage. An important factor related with the measure of gas mixture detonability is the detonation cell size which correlates with the critical tube diameter and detonation initiation energy. A numerical kinetic study is presented of the influence of carbon monoxide admixtures (from 0 vol.% to 40 vol.%) upon the sensitivity (detonation cell size) of the dry hydrogen-air gas mixtures to detonation in post-accident containment atmosphere. (author). 3 refs., 3 figs

  14. Effects of precipitation regime and soil nitrogen on leaf traits in seasonally dry tropical forests of the Yucatan Peninsula, Mexico.

    Science.gov (United States)

    Roa-Fuentes, Lilia L; Templer, Pamela H; Campo, Julio

    2015-10-01

    Leaf traits are closely associated with nutrient use by plants and can be utilized as a proxy for nutrient cycling processes. However, open questions remain, in particular regarding the variability of leaf traits within and across seasonally dry tropical forests. To address this, we considered six leaf traits (specific area, thickness, dry matter content, N content, P content and natural abundance (15)N) of four co-occurring tree species (two that are not associated with N2-fixing bacteria and two that are associated with N2-fixing bacteria) and net N mineralization rates and inorganic N concentrations along a precipitation gradient (537-1036 mm per year) in the Yucatan Peninsula, Mexico. Specifically we sought to test the hypothesis that leaf traits of dominant plant species shift along a precipitation gradient, but are affected by soil N cycling. Although variation among different species within each site explains some leaf trait variation, there is also a high level of variability across sites, suggesting that factors other than precipitation regime more strongly influence leaf traits. Principal component analyses indicated that across sites and tree species, covariation in leaf traits is an indicator of soil N availability. Patterns of natural abundance (15)N in foliage and foliage minus soil suggest that variation in precipitation regime drives a shift in plant N acquisition and the openness of the N cycle. Overall, our study shows that both plant species and site are important determinants of leaf traits, and that the leaf trait spectrum is correlated with soil N cycling.

  15. Analysis of the NASA AirMOSS Root Zone Soil Water and Soil Temperature from Three North American Ecosystems

    Science.gov (United States)

    Hagimoto, Y.; Cuenca, R. H.

    2015-12-01

    Root zone soil water and temperature are controlling factors for soil organic matter accumulation and decomposition which contribute significantly to the CO2 flux of different ecosystems. An in-situ soil observation protocol developed at Oregon State University has been deployed to observe soil water and temperature dynamics in seven ecological research sites in North America as part of the NASA AirMOSS project. Three instrumented profiles defining a transect of less than 200 m are installed at each site. All three profiles collect data for in-situ water and temperature dynamics employing seven soil water and temperature sensors installed at seven depth levels and one infrared surface temperature sensor monitoring the top of the profile. In addition, two soil heat flux plates and associated thermocouples are installed at one of three profiles at each site. At each profile, a small 80 cm deep access hole is typically made, and all below ground sensors are installed into undisturbed soil on the side of the hole. The hole is carefully refilled and compacted so that root zone soil water and temperature dynamics can be observed with minimum site disturbance. This study focuses on the data collected from three sites: a) Tonzi Ranch, CA; b) Metolius, OR and c) BERMS Old Jack Pine Site, Saskatchewan, Canada. The study describes the significantly different seasonal root zone water and temperature dynamics under the various physical and biological conditions at each site. In addition, this study compares the soil heat flux values estimated by the standard installation using the heat flux plates and thermocouples installed near the surface with those estimated by resolving the soil heat storage based on the soil water and temperature data collected over the total soil profile.

  16. Effect of dry mycelium of Penicillium chrysogenum fertilizer on soil microbial community composition, enzyme activities and snap bean growth.

    Science.gov (United States)

    Wang, Bing; Liu, Huiling; Cai, Chen; Thabit, Mohamed; Wang, Pu; Li, Guomin; Duan, Ziheng

    2016-10-01

    The dry mycelium fertilizer (DMF) was produced from penicillin fermentation fungi mycelium (PFFM) following an acid-heating pretreatment to degrade the residual penicillin. In this study, it was applied into soil as fertilizer to investigate its effects on soil properties, phytotoxicity, microbial community composition, enzyme activities, and growth of snap bean in greenhouse. As the results show, pH, total nitrogen, total phosphorus, total potassium, and organic matter of soil with DMF treatments were generally higher than CON treatment. In addition, the applied DMF did not cause heavy metal and residual drug pollution of the modified soil. The lowest GI values (<0.3) were recorded at DMF8 (36 kg DMF/plat) on the first days after applying the fertilizer, indicating that severe phytotoxicity appeared in the DMF8-modified soil. Results of microbial population and enzyme activities illustrated that DMF was rapidly decomposed and the decomposition process significantly affected microbial growth and enzyme activities. The DMF-modified soil phytotoxicity decreased at the late fertilization time. DMF1 was considered as the optimum amount of DMF dose based on principal component analysis scores. Plant height and plant yield of snap bean were remarkably enhanced with the optimum DMF dose.

  17. Drying characteristics of garlic ( Allium sativum L) slices in a convective hot air dryer

    Science.gov (United States)

    Demiray, Engin; Tulek, Yahya

    2014-06-01

    The effects of drying temperatures on the drying kinetics of garlic slices were investigated using a cabinet-type dryer. The experimental drying data were fitted best to the Page and Modified Page models apart from other theoretical models to predict the drying kinetics. The effective moisture diffusivities varied from 4.214 × 10-10 to 2.221 × 10-10 m2 s-1 over the temperature range studied, and activation energy was 30.582 kJ mol-1.

  18. Dry deposition models for radionuclides dispersed in air: a new approach for deposition velocity evaluation schema

    Science.gov (United States)

    Giardina, M.; Buffa, P.; Cervone, A.; De Rosa, F.; Lombardo, C.; Casamirra, M.

    2017-11-01

    In the framework of a National Research Program funded by the Italian Minister of Economic Development, the Department of Energy, Information Engineering and Mathematical Models (DEIM) of Palermo University and ENEA Research Centre of Bologna, Italy are performing several research activities to study physical models and mathematical approaches aimed at investigating dry deposition mechanisms of radioactive pollutants. On the basis of such studies, a new approach to evaluate the dry deposition velocity for particles is proposed. Comparisons with some literature experimental data show that the proposed dry deposition scheme can capture the main phenomena involved in the dry deposition process successfully.

  19. Radon as a tracer for soil-gas entry into a house located next to a contaminated dry-cleaning property; Radon som sporgas for jordluftindtraengning til hus ved forurenet renserigrund

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, C.E

    2001-07-01

    This study applies the naturally occurring radioactive gas radon-222 as a tracer for soil-gas entry into a house located next to a dry-cleaners shop. This is possible because the concentration of radon in the soil below the house is about 1000 times higher than the concentration in outdoor air. The study is based on continuous indoor measurement of radon, differential pressures, barometric pressure and temperatures and grab samples of radon below the slab and in the soil in the vicinity of the house. During the investigation, vacuum extraction were used to remove chlorinated solvents (perchloroethylene, PCE) from the unsaturated zone. The study shows that the vacuum extraction influences the radon concentration in and below the house. When the vacuum pump is on, the indoor radon concentration is only 10 Bq/m{sup 3} corresponding to the contribution from radon in outdoor air and exhalation from building materials. When the vacuum pump is set off, the average indoor radon concentration increases to 30 Bq/m{sup 3}. It is believed that the increase is caused by radon entry from the soil. Regression analysis demonstrates that changes in the indoor radon concentration can be explained by changes in indoor-outdoor pressure differences and changes in the atmospheric pressure. This suggests that advection is the primary mode of entry. Under some highly simplifying assumptions the soil-gas entry is found to be around 1 m{sup 3}/h. This, however, is most likely an overestimate. Based on the measured radon concentration in the exhaust air from the vacuum system and a typical radon emanation rate for Danish soil, it is estimated that the soil vapor extraction system ventilates about 10000 m{sup 3} of soil. The investigation is supported by numerical model calculations with the finite-volume model Rnmod3d. (au)

  20. Drying of fruits and vegetables using a flat plate solar collector with convective air flow

    International Nuclear Information System (INIS)

    Mansoor, K.K.; Hanif, M.

    2011-01-01

    This paper presents the analysis of drying of different fruits and vegetables dried by a flat plate solar collector developed at the Department of Agricultural Mechanization, Khyber PukhtunKhwa Agricultural University Peshawar, Pakistan. A small flat plate solar collector is designed and tested for its maximum performance in terms of efficiency with different convective flow rates. The collector assembly is divided into two parts. The flat plate solar collector and the drying chamber. The materials used for flat plate solar collector are wood, steel sheet, Insulation materials, and glass sheet as covering material. The insulation box (0.9 x 1.8 x 0.3 meter) is made up of wood of popular and deodar, to be fully isolated with the help of polystyrene. The absorber is black painted v-corrugated steel sheet. Collector has a tilt angle of 34 deg. (Equivalent to the latitude of Peshawar). The covering material is (0.9 x 1.8 meter) and 5 mm thick glass sheet placed at the top of the wooden box. The collector is supported and tilted with the help of a frame made up of iron angled arms. While the drying chamber is a (1 X 0.5 x 0.3 meter) wooden box connected to the outlet duct of the collector with the help of polyvinylchloride pipe. Experiments were conducted different fruits and vegetables and different parameters like moisture lost by the products in each hour, drying rate at each hour of drying, humidity and temperature of the drying chamber. It was observed that the products such as bitter guard and onion were dried in 10 to 2 hours up to moisture content less then 8%. These two product lost 8% to 10% moisture during each hour of drying. While grapes and Green chili are dried in 24 to 25 hours up to moisture content less then 8%. These two products lost 4% to 5% moisture in each hour of drying. The drying rate of all the products dried was very much consistent. It was observed that onion and bitter guard showed a good drying rate of 0.03[g(H/sub 2/O)/g(d.m).cm/ 2 hr] to

  1. Increasing thermal drying temperature of biosolids reduced nitrogen mineralisation and soil N2O emissions

    DEFF Research Database (Denmark)

    Case, Sean; Gomez Muñoz, Beatriz; Magid, Jakob

    2016-01-01

    Previous studies found that thermally dried biosolids contained more mineralisable organic nitrogen (N) than the raw or anaerobically digested (AD) biosolids they were derived from. However, the effect of thermal drying temperature on biosolid N availability is not well understood. This will be o......Previous studies found that thermally dried biosolids contained more mineralisable organic nitrogen (N) than the raw or anaerobically digested (AD) biosolids they were derived from. However, the effect of thermal drying temperature on biosolid N availability is not well understood...

  2. Air-drying paint compositions comprising carbohydrate-based polyesters and polyester preparation

    NARCIS (Netherlands)

    Oostveen, E.A.; Weijnen, J.; Haveren, van J.; Gillard, M.

    2003-01-01

    The invention relates to a polyester obtainable by transesterification or interesterification of:(i) a carbohydrate or an acyl ester thereof, (ii) an alkyl ester of a drying fatty acid, semi-drying fatty acid or mixture thereof; and (iii) an alkyl ester of a non aromatic polycarboxylic acid. The

  3. Moisture Distribution in Broccoli: Measurements by MRI Hot Air Drying Experiments

    NARCIS (Netherlands)

    Jin, X.; Sman, van der R.G.M.; Gerkema, E.; Vergeldt, F.J.; As, van H.; Boxtel, van A.J.B.

    2011-01-01

    ABSTRACT The internal moisture distribution that arise in food products during drying, is a key factor for the retention of quality attributes. To reveal the course of moisture content in a product, internal moisture profiles in broccoli florets are measured by MRI imaging during drying experiments

  4. Moisture distribution in broccoli: measurements by MRI hot air drying experiments

    NARCIS (Netherlands)

    Jin, X.; Sman, van der R.G.M.; Gerkema, E.; Vergeldt, F.J.; As, van H.; Boxtel, van A.J.B.

    2011-01-01

    The internal moisture distribution that arise in food products during drying, is a key factor for the retention of quality attributes. To reveal the course of moisture content in a product, internal moisture profiles in broccoli florets are measured by MRI imaging during drying experiments with

  5. Postharvest monitoring of organic potato (cv. Anuschka) during hot-air drying using visible-NIR hyperspectral imaging.

    Science.gov (United States)

    Moscetti, Roberto; Sturm, Barbara; Crichton, Stuart Oj; Amjad, Waseem; Massantini, Riccardo

    2018-05-01

    The potential of hyperspectral imaging (500-1010 nm) was evaluated for monitoring of the quality of potato slices (var. Anuschka) of 5, 7 and 9 mm thickness subjected to air drying at 50 °C. The study investigated three different feature selection methods for the prediction of dry basis moisture content and colour of potato slices using partial least squares regression (PLS). The feature selection strategies tested include interval PLS regression (iPLS), and differences and ratios between raw reflectance values for each possible pair of wavelengths (R[λ 1 ]-R[λ 2 ] and R[λ 1 ]:R[λ 2 ], respectively). Moreover, the combination of spectral and spatial domains was tested. Excellent results were obtained using the iPLS algorithm. However, features from both datasets of raw reflectance differences and ratios represent suitable alternatives for development of low-complex prediction models. Finally, the dry basis moisture content was high accurately predicted by combining spectral data (i.e. R[511 nm]-R[994 nm]) and spatial domain (i.e. relative area shrinkage of slice). Modelling the data acquired during drying through hyperspectral imaging can provide useful information concerning the chemical and physicochemical changes of the product. With all this information, the proposed approach lays the foundations for a more efficient smart dryer that can be designed and its process optimized for drying of potato slices. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  6. Variation in the sugar yield in response to drying-off of sugarcane before harvest and the occurrence of low air temperatures

    Directory of Open Access Journals (Sweden)

    Renato Araújo

    2016-03-01

    Full Text Available ABSTRACT The need to irrigate sugarcane in the Brazilian Savanna is due to the lack of rain from April to September. For efficient sugar accumulation, the crop needs water stress or heat stress at the maturation stage. However, when the water deficit is intense at this stage, it occurs the reduction in crop production. The objective of this study was: (i to assess the quality of the raw material of sugarcane in different drying-off seasons before harvest; (ii to evaluate the influence of heat stress on the culture. The experiment was conducted in Santo Antônio de Goiás (GO, Brazil, in Oxisol, with CTC4 variety in cane-plant cycle. A randomized block design in a split-plot array in time was used. The treatments of the plots were five drying-off times (90, 60, 30, 15 and 0 days before harvest and, in the subplots, five seasons of the yield evaluation. Irrigation was carried out by surface drip method, which provided 50% of crop water requirement. The best results for sugar yield occurred 30 days before harvest, period in which the crop irrigation could be interrupted. The water deficit of 37.76 mm appears to be the critical limit of water shortage in the soil, from which the sugarcane yield starts to be reduced. The sugar concentration in the stalk was more influenced by low air temperatures than sugarcane yield.

  7. Mathematical modeling of convective air drying of quinoa-supplemented feed for laboratory rats

    Directory of Open Access Journals (Sweden)

    Antonio Vega-Gálvez

    2011-02-01

    Full Text Available Drying kinetics of quinoa-supplemented feed for laboratory rats during processing at 50, 60, 70, 80 and 90ºC was studied and modeled in this work. Desorption isotherm was obtained at 60ºC giving a monolayer moisture content of 0.04 g water/g d.m. The experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying equations available in the literature were evaluated based on determination coefficient (r², sum squared errors (SSE and Chi-square (χ2 statisticals. In comparison to the experimental moisture values, the values estimated with the Logarithmic model gave the best fit quality (r² >0.994, SSE < 0.00015 and χ2 < 0.00018, showing this equation could predict very accurately the drying time of rat feed under the operative conditions applied.

  8. Simple Laboratory Experiment for Illustrating Soil Respiration.

    Science.gov (United States)

    Hattey, J. A.; Johnson, G. V.

    1997-01-01

    Describes an experiment to illustrate the effect of food source and added nutrients (N) on microbial activity in the soil. Supplies include air-dried soil, dried plant material, sources of carbon and nitrogen, a trap such as KOH, colored water, and a 500-mL Erlenmeyer flask. Includes a diagram of an incubation chamber to demonstrate microbial…

  9. Air-soil exchange of organochlorine pesticides in a sealed chamber.

    Science.gov (United States)

    Yang, Bing; Han, Baolu; Xue, Nandong; Zhou, Lingli; Li, Fasheng

    2015-01-01

    So far little is known about air-soil exchange under any sealed circumstances (e.g., in plastic and glass sheds), which however has huge implications for the soil-air-plant pathways of persistent organic pollutants including organochlorine pesticides (OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs (hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air-soil exchange of persistent organic pollutants in any sealed conditions is discussed. Copyright © 2014. Published by Elsevier B.V.

  10. Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya

    NARCIS (Netherlands)

    Muniafu, M.M.; Macharia, J.N.M.; Stigter, C.J.; Coulson, G.L.

    1999-01-01

    Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. cv GLP-2 under two soil moisture levels in two contrasting seasons near Nairobi, Kenya were investigated. The experiment confirms that dry weights and yields of Phaseolus vulgaris are

  11. Warm Dry Weather Conditions Cause of 2016 Fort McMurray Wild Forest Fire and Associated Air Quality

    Science.gov (United States)

    de Azevedo, S. C.; Singh, R. P.; da Silva, E. A., Sr.

    2016-12-01

    The climate change is evident from the increasing temperature around the world, day to day life and increasing frequency of natural hazards. The warm and dry conditions are the cause of frequent forest fires around the globe. Forest fires severely affect the air quality and human health. Multi sensor satellites and dense network of ground stations provide information about vegetation health, meteorological, air quality and atmospheric parameters. We have carried out detailed analysis of satellite and ground data of wild forest fire that occurred in May 2016 in Fort McMurray, Alberta, Canada. This wild forest fire destroyed 10 per cent of Fort McMurray's housing and forced more than 90,000 people to evacuate the surrounding areas. Our results show that the warm and dry conditions with low rainfall were the cause of Fort McMurray wild fire. The air quality parameters (particulate matter, CO, ozone, NO2, methane) and greenhouse gases measured from Atmospheric Infrared Sounder (AIRS) satellite show enhanced levels soon after the forest fire. The emissions from the forest fire affected health of population living in surrounding areas up to 300 km radius.

  12. Growth and death of bacteria and fungi underlie rainfall-induced carbon dioxide pulses from seasonally dried soil.

    Science.gov (United States)

    Blazewicz, Steven J; Schwartz, Egbert; Firestone, Mary K

    2014-05-01

    The rapid increase in microbial activity that occurs when a dry soil is rewetted has been well documented and is of great interest due to implications of changing precipitation patterns on soil C dynamics. Several studies have shown minor net changes in microbial population diversity or abundance following wet-up, but the gross population dynamics of bacteria and fungi resulting from soil wet-up are virtually unknown. Here we applied DNA stable isotope probing with H218O coupled with quantitative PCR to characterize new growth, survival, and mortality of bacteria and fungi following the rewetting of a seasonally dried California annual grassland soil. Microbial activity, as determined by CO2 production, increased significantly within three hours of wet-up, yet new growth was not detected until after three hours, suggesting a pulse of nongrowth activity immediately following wet-up, likely due to osmo-regulation and resuscitation from dormancy in response to the rapid change in water potential. Total microbial abundance revealed little change throughout the seven-day post-wet incubation, but there was substantial turnover of both bacterial and fungal populations (49% and 52%, respectively). New growth was linear between 24 and 168 hours for both bacteria and fungi, with average growth rates of 2.3 x 10(8) bacterial 16S rRNA gene copies x [g dry mass](-1) x h(-1) and 4.3 x 10(7) fungal ITS copies x [g dry mass](-1) x h(-1). While bacteria and fungi differed in their mortality and survival characteristics during the seven-day incubation, mortality that occurred within the first three hours was similar, with 25% and 27% of bacterial and fungal gene copies disappearing from the pre-wet community, respectively. The rapid disappearance of gene copies indicates that cell death, occurring either during the extreme dry down period (preceding five months) or during the rapid change in water potential due to wet-up, generates a significant pool of available C that likely

  13. Adaptive transgenerational plasticity in an annual plant: grandparental and parental drought stress enhance performance of seedlings in dry soil.

    Science.gov (United States)

    Herman, Jacob J; Sultan, Sonia E; Horgan-Kobelski, Tim; Riggs, Charlotte

    2012-07-01

    Stressful parental (usually maternal) environments can dramatically influence expression of traits in offspring, in some cases resulting in phenotypes that are adaptive to the inducing stress. The ecological and evolutionary impact of such transgenerational plasticity depends on both its persistence across generations and its adaptive value. Few studies have examined both aspects of transgenerational plasticity within a given system. Here we report the results of a growth-chamber study of adaptive transgenerational plasticity across two generations, using the widespread annual plant Polygonum persicaria as a naturally evolved model system. We grew five inbred Polygonum genetic lines in controlled dry vs. moist soil environments for two generations in a fully factorial design, producing replicate individuals of each genetic line with all permutations of grandparental and parental environment. We then measured the effects of these two-generational stress histories on traits critical for functioning in dry soil, in a third (grandchild) generation of seedling offspring raised in the dry treatment. Both grandparental and parental moisture environment significantly influenced seedling development: seedlings of drought-stressed grandparents or parents produced longer root systems that extended deeper and faster into dry soil compared with seedlings of the same genetic lines whose grandparents and/or parents had been amply watered. Offspring of stressed individuals also grew to a greater biomass than offspring of nonstressed parents and grandparents. Importantly, the effects of drought were cumulative over the course of two generations: when both grandparents and parents were drought-stressed, offspring had the greatest provisioning, germinated earliest, and developed into the largest seedlings with the most extensive root systems. Along with these functionally appropriate developmental effects, seedlings produced after two previous drought-stressed generations had

  14. Diversity and production of Ethiopian dry woodlands explained by climate- and soil- stress gradients

    NARCIS (Netherlands)

    Eshete, A.; Sterck, F.J.; Bongers, F.

    2011-01-01

    Dry woodlands cover about 14% of the total African land surface and represent about 25% of the natural vegetation. They are characterized by a seasonal climate, with a dry season of 4–7 months. Large parts of these ecosystems are degrading due to grazing, fire or exploitation by people. We studied

  15. Elaboration of amniotic membrane dressing dried by air and irradiated - Peruvian experience

    International Nuclear Information System (INIS)

    Gamero, E.C.; Perez Caballero, N.

    1999-01-01

    The purpose of this work is to prepare dressings from the amniotic membrane to be used in cases of skin damage principally due to superficial and intermediate second-degree burns. The amnion is a transparent membrane that lines the chorion. It is resistant and rich in collagen. Due to these characteristics it can be well used as biological dressing as it diminishes the loss of fluids, electrolytes and proteins, it also protects the growing epithelium and adheres well to the surface of the wound, improves mobility of the patient, diminishing pain and stimulating neovascularization. The ISN-IPEN Tissue Bank promoted by IAEA has processed amniotic membrane since July 1997. Initially dressings were prepared using antibiotics, after IAEA training at the MINT of Malaysia, it is processed dried by air, lyophylized and in both presentations, sterilized by gamma-rays. Amniotic membranes are procured from Lima Maternity. Tissues must comply with VDRL, HIV, Hepatitis B and C exclusion tests. The process is held in a laminar flow hood and amnion already separated from the chorion is washed with sterile distilled water, a solution of 0.05% sodium hypochlorite, and normal saline. Then it is cut into appropriate sizes and double packed in PE films. The dressings are then carried to the Peruvian Institute of Nuclear Energy for irradiation, depending on the number of samples either irradiated with gamma-rays at the Gammacell 220 or at the Irradiation Facility located in Santa Anita. The delivered dose is 25 kGy. The product is only released if it complies with the end product quality controls. Meanwhile, microbiological tests are carried out during all the processing stages, in order to monitor the microbial load during production. In conclusion we can state that dressings prepared as above mentioned have the following advantages: not complicated preparation; reliable and safe for clinical use; diminish infection rates and days spent in the hospital; easy to storage; and can be

  16. Kinetics, mass transport characteristics, and structural changes during air-drying of purple yam (Dioscorea Alata L.) at different process conditions

    Science.gov (United States)

    De Vera, Flordeliza C.; Comaling, Leif Anthony B.; Lao, Iya Ray Alyanna M.; Caparanga, Alvin R.; Sauli, Zaliman

    2017-11-01

    This experiment was designed to follow the 2k factorial design to study the effects of the three drying parameters on the drying characteristics and effective moisture diffusivity and to fit each run performed on the best thin-layer drying kinetics model. Raw purple yam samples were pre-treated and undergone the designed drying procedures at which the weight of the samples were recorded every minute until such time that the sample weights become constant. Scanning Electron Microscopy (SEM) is utilized for qualitative analysis of the dried samples. The number of pores per unit area and the overall aesthetics of the surface of the dried samples were compared also using SEM. Considering the qualitative analysis conducted on the samples from the images of SEM, dried samples from run 2 has the most desirable conditions such as high temperature and low air velocity for drying because the samples from this run have large pore diameters with minimal cell breakages.

  17. Changes in soil water availability in vineyards can be traced by the carbon and nitrogen isotope composition of dried wines.

    Science.gov (United States)

    Spangenberg, Jorge E; Zufferey, Vivian

    2018-04-13

    The grapevine is one of the most important edible fruit plants cultivated worldwide, and it is highly sensitive to changes in the soil water content. We studied the total carbon and nitrogen contents and stable isotope compositions (C/N WSR , δ 13 C WSR and δ 15 N WSR values) of the solid residues obtained by freeze-drying wines produced from two white grapevine cultivars (Vitis vinifera L. cv Chasselas and Petite Arvine) field grown under different soil water regimes while maintaining other climatic and ecopedological conditions identical. These experiments simulated the more frequent and extended climate change-induced periods of soil water shortage. The wines were from the 2009-2014 vintages, produced using the same vinification procedure. The plant water status, reflecting soil water availability, was assessed by the predawn leaf water potential (Ψ pd ), monitored in the field during the growing seasons. For both wine varieties, the δ 13 C WSR values are highly correlated with Ψ pd values and record the soil water availability set by soil water holding capacity, rainfall and irrigation water supply. These relationships were the same as those observed for the carbon isotope composition of fruit sugars (i.e., must sugars) and plant water status. In Chasselas wines, the nitrogen content and δ 15 N WSR values decreased with soil water deficit, indicating control of the flux of soil-water soluble nutrients into plants by soil water availability. Such a correlation was not found for Petite Arvine, probably due to different N-metabolism processes in this genetically atypical cultivar. The results presented in this study confirm and generalize what was previously found for red wine (Pinot noir); the carbon isotope composition of wine solid residues is a reliable indicator of the soil and the plant water status and thus can be used to trace back local climatic conditions in the vineyard's region. In most wines (except Petite Arvine) the C/N WSR and δ 15 N WSR

  18. [Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain].

    Science.gov (United States)

    Vázquez, María B; Amodeo, Martín R; Bianchinotti, María V

    Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

    OpenAIRE

    Samuel Enahoro Agarry

    2017-01-01

    The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h a...

  20. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)

    Energy Technology Data Exchange (ETDEWEB)

    Mikes, Ondrej; Cupr, Pavel [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Trapp, Stefan [Department of Environmental Engineering, Technical University of Denmark, Miljoevej 113, DK-2800 Kgs. Lyngby (Denmark); Klanova, Jana [RECETOX, Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic)], E-mail: klanova@recetox.muni.cz

    2009-02-15

    Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for {beta}-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K{sub OW}. A negative correlation between BCF and log K{sub OW} was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K{sub OA}. - Uptake from air represented for majority of persistent organochlorines a dominant pathway into shoots while uptake from soil was dominant for roots.

  1. Wet-dry seasonal and vertical geochemical variations in soil water and their driving forces under different land covers in southwest China karst

    Science.gov (United States)

    Wang, Peng; Hu, Bill X.; Wu, Chuanhao; Xu, Kai

    2017-04-01

    Karst aquifers supply drinking water for 25% of the world's population, and they are, however, vulnerable to climate change. Bimonthly hydrochemical data in karst soil water samples from July 2010 to July 2011 were obtained to reveal the seasonal and vertical geochemical variations in soil water under five vegetation types in Qingmuguan, a small karst catchment in southwest China. Soil water chemistry was dominated by Ca2+, HCO3-, and SO42- because of the dissolution of limestone, dolomite, and gypsum minerals in the strata. The predominant hydrochemical types in soil water were Ca2+-HCO3-, Ca2+-SO42-, and mixed Ca2+-HCO3-SO42-. Ca2+ and HCO3- concentrations ranked in the following order: shrub land > dry land > afforestation farmland > bamboo land > grassland. In warm and wet seasons, the main ion concentrations in soil water from grasslands were low. Na+, K+, Ca2+, Mg2+, HCO3-, SO42-, and Cl- concentrations in soil water from other lands were high. An opposite trend was observed in cold and dry seasons. Marked seasonal variations were observed in Ca2+, HCO3-, and NO3- in soil water from dry land. The main ion concentrations in soil water from bamboo lands decreased as soil depth increased. By contrast, the chemistry of soil water from other lands increased as soil depth increased. Their ions were accumulated in depth. A consistent high and low variation between the main ions in soil water and the contents of carbonate and CO2 was found in the soil. Hydrochemical changes in soil water were regulated by the effects of dilution and soil CO2.

  2. Influence of temperature and soil drying on respiration of individual roots in citrus: integrating greenhouse observations into a predictive model for the field

    NARCIS (Netherlands)

    Bryla, D.R.; Bouma, T.J.; Hartmond, U.; Eissenstat, D.M.

    2001-01-01

    In citrus, the majority of fine roots are distributed near the soil surface - a region where conditions are frequently dry and temperatures fluctuate considerably. To develop a better understanding of the relationship between changes in soil conditions and a plant's below-ground respiratory costs,

  3. Contact angles at the water-air interface of hydrocarbon-contaminated soils and clay minerals

    Science.gov (United States)

    Sofinskaya, O. A.; Kosterin, A. V.; Kosterina, E. A.

    2016-12-01

    Contact angles at the water-air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic-hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1-3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil-water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.

  4. Coal mining activities change plant community structure due to air pollution and soil degradation.

    Science.gov (United States)

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  5. Dynamics of Soil Water Evaporation during Soil Drying in the Presence of a Shallow Water Table: Laboratory Experiment and Numerical Analysis

    Science.gov (United States)

    Han, J.; Lin, J.; Liu, P.; Li, W.

    2017-12-01

    Evaporation from a porous medium plays a key role in hydrological, agricultural, environmental, and engineering applications. Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68 cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71 cm during stage 3. Although the magnitude of condensation zone was much smaller than that for the evaporation zone, the importance of the contribution of condensation zone to soil water dynamics should not be underestimated. Results from our experiment and numerical simulation show that this condensation process resulted in an unexpected and apparent water content increase in the middle of vadose zone profile.

  6. Modeling aerosol suspension from soils and oceans as sources of micropollutants to air.

    Science.gov (United States)

    Qureshi, Asif; MacLeod, Matthew; Hungerbühler, Konrad

    2009-10-01

    Soil and marine aerosol suspension are two physical mass transfer processes that are not usually included in models describing fate and transport of environmental pollutants. Here, we review the literature on soil and marine aerosol suspension and estimate aerosol suspension mass transfer velocities for inclusion in multimedia models, as a global average and on a 1 x 1 scale. The yearly, global average mass transfer velocity for soil aerosol suspension is estimated to be 6 x 10(-10)mh(-1), approximately an order of magnitude smaller than marine aerosol suspension, which is estimated to be 8 x 10(-9)mh(-1). Monthly averages of these velocities can be as high as 10(-7)mh(-1) and 10(-5)mh(-1) for soil and marine aerosol suspension, respectively, depending on location. We use a unit-world multimedia model to analyze the relevance of these two suspension processes as a mechanism that enhances long-range atmospheric transport of pollutants. This is done by monitoring a metric of long-range transport potential, phi-one thousand (phi1000), that denotes the fraction of modeled emissions to air, water or soil in a source region that reaches a distance of 1000 km in air. We find that when the yearly, globally averaged mass transfer velocity is used, marine aerosol suspension increases phi1000 only fractionally for both emissions to air and water. However, enrichment of substances in marine aerosols, or speciation between ionic and neutral forms in ocean water may increase the influence of this surface-to-air transfer process. Soil aerosol suspension can be the dominant process for soil-to-air transfer in an emission-to-soil scenario for certain substances that have a high affinity to soil. When a suspension mass transfer velocity near the maximum limit is used, soil suspension remains important if the emissions are made to soil, and marine aerosol suspension becomes important regardless of if emissions are made to air or water compartments. We recommend that multimedia models

  7. Toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus changes under a global warming perspective: Variations in air temperature and soil moisture content

    NARCIS (Netherlands)

    Gonzalez Alcaraz, M.N.; van Gestel, C.A.M.

    2016-01-01

    This study aimed to assess how the current global warming perspective, with increasing air temperature (20 °C vs. 25 °C) and decreasing soil moisture content (50% vs. 30% of the soil water holding capacity, WHC), affected the toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus

  8. X-Ray Amorphous Phases in Antarctica Dry Valley Soils: Insight into Aqueous Alteration Processes on Mars?

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.; Rampe, E. B.; Golden, D. C.; Quinn, J. E.

    2015-01-01

    The Chemistry and Mineralogy (CheMin) instrument onboard the Mars Curiosity rover has detected abundant amounts (approx. 25-30 weight percentage) of X-ray amorphous materials in a windblown deposit (Rocknest) and in a sedimentary mudstone (Cumberland and John Klein) in Gale crater, Mars. On Earth, X-ray amorphous components are common in soils and sediments, but usually not as abundant as detected in Gale crater. One hypothesis for the abundant X-ray amorphous materials on Mars is limited interaction of liquid water with surface materials, kinetically inhibiting maturation to more crystalline phases. The objective of this study was to characterize the chemistry and mineralogy of soils formed in the Antarctica Dry Valleys, one of the driest locations on Earth. Two soils were characterized from different elevations, including a low elevation, coastal, subxerous soil in Taylor Valley and a high elevation, ultraxerous soil in University Valley. A variety of techniques were used to characterize materials from each soil horizon, including Rietveld analysis of X-ray diffraction data. For Taylor Valley soil, the X-ray amorphous component ranged from about 4 weight percentage in the upper horizon to as high as 15 weight percentage in the lowest horizon just above the permafrost layer. Transmission electron microscopy indicated that the presence of short-range ordered (SRO) smectite was the most likely candidate for the X-ray amorphous materials in the Taylor Valley soils. The SRO smectite is likely an aqueous alteration product of mica inherited from granitic materials during glaciation of Taylor Valley. The drier University Valley soils had lower X-ray amorphous contents of about 5 weight percentage in the lowest horizon. The X-ray amorphous materials in University Valley are attributed to nanoparticles of TiO2 and possibly amorphous SiO2. The high abundance of X-ray amorphous materials in Taylor Valley is surprising for one of the driest places on Earth. These materials

  9. The Influence of Sample Drying Procedures on Mercury Concentrations Analyzed in Soils

    Czech Academy of Sciences Publication Activity Database

    Hojdová, Maria; Rohovec, Jan; Chrastný, V.; Penížek, V.; Navrátil, Tomáš

    2015-01-01

    Roč. 94, č. 5 (2015), s. 570-576 ISSN 0007-4861 R&D Projects: GA ČR GP526/09/P404; GA ČR(CZ) GAP210/11/1369 Institutional support: RVO:67985831 Keywords : sample preparation * drying procedures * microbial activity * freeze-drying * contamination Subject RIV: DD - Geochemistry Impact factor: 1.191, year: 2015

  10. Effects of drying method, storage period and carbon: nitrogen ratio ...

    African Journals Online (AJOL)

    Taghwo

    2012-12-03

    Dec 3, 2012 ... African Journal of Environmental Science and Technology Vol. 6(12), pp. .... Drying method 2 (method 2) involved air drying field- fresh soil ... then packed in polyethylene bags and stored at -10°C until inorganic N extraction ...

  11. Liming efficacy and transport in soil of a dry PFBC by-product

    International Nuclear Information System (INIS)

    Dick, W.A.

    1995-01-01

    The by-products of pressurized fluidized-bed combustion (PFBC) systems are mixtures of coal ash, anhydrite (CaSO 4 ), and unspent alkaline sorbent. Because PFBC by-products are alkaline and contain large concentrations of readily soluble bases (Ca and in some cases Mg) and other essential plant nutrients such as S and K, they have potential use as soil amendments, especially in acidic soils. PFBC by-products (particularly those with large Mg contents) may cause excessively high soluble salt concentrations when applied to soil. This could be detrimental to plant growth and might also impact the release of trace elements from the coal ash component of the by-product. In field experiments on three acidic soils, the liming effectiveness of a PFBC by-product, its effects on corn and alfalfa growth, and its impacts on crop, soil, and water quality were investigated

  12. Modeling Air Permeability in Variably Saturated Soil from Two Natural Clay Gradients

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda T K K; Arthur, Emmanuel; Møldrup, Per

    2013-01-01

    measurements from two Danish arable fields, each located on natural clay gradients, this study presents a pore tortuosity–disconnectivity analysis to characterize the soil–gas phase. The main objective of this study is to investigate the effect of soil–moisture condition, clay content, and other potential......Understanding soil–gas phase properties and processes is important for finding solutions to critical environmental problems such as greenhouse gas emissions and transport of gaseous-phase contaminants in soils. Soil–air permeability, ka (μm2), is the key parameter governing advective gas movement...... in soil and is controlled by soil physical characteristics representing soil texture and structure. Models predicting ka as a function of air-filled porosity (ɛ) often use a reference-point measurement, for example, ka,1000 at ɛ1000 (where the measurement is done at a suction of –1000 cm H2O). Using ka...

  13. Utilization of air pollution control residues for the stabilization/solidification of trace element contaminated soil.

    Science.gov (United States)

    Travar, I; Kihl, A; Kumpiene, J

    2015-12-01

    The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30% APCR/70% soil and 50% APCR/50% soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39-93% in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca3(AsO4)2/4H2O) and incorporation of As in ettringite (Ca6Al2(SO4)3(OH)12 · 26H2O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter.

  14. determination of elemental composition of air particulates and soils

    African Journals Online (AJOL)

    Mgina

    Department of Physics, Faculty of Science. University ... collecting airborne particles with an aerodynamic diameter of 2.5 μm. Energy ... have elevated concentrations compared to the background air levels. ... part of the total mass of street dust,.

  15. Improved Formulations for Air-Surface Exchanges Related to National Security Needs: Dry Deposition Models

    Energy Technology Data Exchange (ETDEWEB)

    Droppo, James G.

    2006-07-01

    The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and

  16. The soil and air quality connection: abstracts of the 36. Alberta soil science workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    The workshop has the following general categories of papers (with abstracts only): plenary session, volunteer session I; volunteer session II; technical session I - soil reclamation, and soil fertility; technical session II - soil conservation, and soil information; and poster presentations. Twelve individual papers are abstracted/indexed as follows: (1) greenhouse gas emissions from Canadian prairie agriculture; (2) acid deposition, critical loads, soil sensitivity, and environmental responses; (3) the downwind health risks of intensive livestock production; (4) nitrous oxide emission as affected by tillage practices and fertilizer association; (5) a conceptual system for assigning sensitivities to potentially acidifying inputs to soils in the oil sands regions of Alberta; (6) a particle tracer method for soil aggregation and translocation studies; (7) DNA adduct quantification in Eisenia fetida after subchronic exposures to creosote contaminated soils; (8) the physical distribution of anthropogenic mercury in nine contaminated soils; (9) bioremediation of hydrocarbon-contaminated soils: are treatability and ecotoxicity endpoints related?; (10) land reclamation using oil sand processing tailings: a field study; (11) assessment of toxicity based criteria for disposal of drilling waste in oil and gas exploration; and (12) toxicity assessment of approved drilling mud additives in the oil and gas sector.

  17. Effect of water activity and protective solutes on growth and subsequent survival to air-drying of Lactobacillus and Bifidobacterium cultures.

    Science.gov (United States)

    Champagne, Claude P; Raymond, Yves; Simon, Jean-Paul

    2012-08-01

    Probiotic cultures of Lactobacillus plantarum, Lactobacillus rhamnosus, Bifidobacterium longum, Lactobacillus casei and Lactobacillus acidophilus were grown in media having water activities (a (w)) adjusted between 0.99 and 0.94 with NaCl or with a mixture of glycerol and sucrose in order to find conditions of osmotic stress which would still allow for good growth. Cultures grown at a (w) = 0.96 or 0.99 were then recovered by centrifugation, added to a sucrose-phosphate medium and air-dried. In some assays, a 2-h osmotic stress was applied to the cell concentrate prior to air-drying. Assays were also carried out where betaine, glutamate and proline (BGP) supplements were added as protective compounds to the growth or drying media. For most strains, evidence of osmotic stress and benefits of BGP supplementation on growth occurred at a (w) = 0.96. Growing the cells in complex media adjusted at a (w) = 0.96 did not enhance their subsequent survival to air-drying, but applying the 2-h osmotic stress did. Addition of the BGP supplements to the growth medium or in the 2-h stress medium did not enhance survival to air-drying. Furthermore, addition of BGP to a sucrose-phosphate drying medium reduced survival of the cultures to air-drying. This study provides preliminary data for producers of probiotics who wish to use air-drying in replacement of freeze-drying for the stabilization of cultures.

  18. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    Science.gov (United States)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

    2015-02-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

  19. Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

    Science.gov (United States)

    Defrere, D.; Hinz, P.; Downey, E.; Boehm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.; hide

    2016-01-01

    The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feed forward approach to stabilize the path length fluctuations seen by the LBTI nuller uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current

  20. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    International Nuclear Information System (INIS)

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-01-01

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial

  1. Calibration of Soil Available Nitrogen and Water Content with Grain Yield of Dry land Wheat

    Directory of Open Access Journals (Sweden)

    V. Feiziasl

    2017-01-01

    Full Text Available Introduction: Nitrogen (N is one of the most important growth-limiting nutrients for dryland wheat. Mineral nitrogen or ammonium (NH4+ and nitrate (NO3− are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. Nitrogen fertilization in dryland area can increase the use of soil moisture, and improve wheat yields to some extent. Many researchers have been confirmed interactions between water stress and nitrogen fertilizers on wheat, especially under field conditions. Because of water stress affects forms of nitrogen uptake that leads to disorder in plant metabolism, reduction in grain yield and crop quality in dryland condition. On the other hand, use of suitable methods for determining nitrogen requirement can increase dryland wheat production. However, nitrogen recommendations should be based on soil profile content or precipitation. An efficient method for nitrogen fertilizer recommendation involves choosing an effective soil extractant and calibrating soil nitrogen (Total N, NO3− andNH4+ tests against yield responses to applied nitrogen in field experiments. Soil testing enables initial N supply to be measured and N supply throughout the season due to mineralization to be estimated. This study was carried out to establish relationship between nitrogen forms (Total N, NO3− andNH4+ in soil and soil profile water content with plant response for recommendation of nitrogen fertilizer. Materials and Methods: This study was carried out in split-split plot in a RCBD in Dryland Agricultural Research Institute (DARI, Maragheh, Iranwhere N application times (fall, 2/3 in fall and 1/3 in spring were assigned to the main plots, N rates to sub plot (0, 30, 60 and 90 kg/ha, and 7 dryland wheat genotypes to sub-sub plots (Azar2, Ohadi, Rasad and 1-4 other genotypes in three replications in 2010-2011. Soil samples were collected from 0-20, 20-40, 40-60 and 60-80 cm in sub-sub plots in shooting stage (ZGS32. Ammonium

  2. Physicochemical characteristics of geophagic clayey soils from ...

    African Journals Online (AJOL)

    ONOS

    2010-09-06

    Sep 6, 2010 ... 3School of Health Technology, Central University of Technology, Bloemfontein, Free State, Private Bag X20539. Bloemfontein 9300 .... Table 1. The collected clayey soil samples were air-dried and their physicochemical ...

  3. Unsaturated soil moisture drying and wetting diffusion coefficient measurements in the laboratory.

    Science.gov (United States)

    2009-09-01

    ABSTRACTTransient moisture flow in an unsaturated soil in response to suction changes is controlled by the unsaturated moisture diffusion coefficient. The moisture diffusion coefficient can be determined by measuring suction profiles over time. The l...

  4. Heavy metals contamination of air and soil in Karak solid waste disposal site, Jordan

    International Nuclear Information System (INIS)

    Jiries, A. G.; Jaradat, Q. M.; Momani, K. A.

    1996-01-01

    The level of air and soil pollution in the municipal solid waste disposal site of Karak(Jordan) were investigated during spring of 1995 by monitoring the amounts of heavy metals. The concentration (mg/kg)of Cu, Pb, and Zn in the upper soil were found to have a range of 15.3-39.3, 21.2-38.0 and 60.0-127.0 respectively. However, for the lower soil, the ranges are 13.4-18.9, 18.5-23.7, and 50.6-90.4, respectively. The soil contamination with heavy metals was almost confined to the upper soil in the locations closely surrounding the burning site, which could be accounted to the arid climate conditions of the area. (authors). 20 refs., 3 tabs., 5 figs

  5. Modeling relationship between runoff and soil properties in dry-farming lands, NW Iran

    OpenAIRE

    Vaezi, A. R.; Bahrami, H. A.; Sadeghi, S. H. R.; Mahdian, M. H.

    2010-01-01

    The process of transformation of rainfall into runoff over a catchment is very complex and exhibits both temporal and spatial variability. However, in a semi-arid area this variability is mainly controlled by the physical and chemical properties of the soil surface. Developing an accurate and easily-used model that can appropriately determine the runoff generation value is of strong demand. In this study a simple, an empirically based model developed to explore effect of soil properties on ru...

  6. Impact of rainfall interception on hydrologic partitioning and soil erosion in natural and managed seasonally dry ecosystems

    Science.gov (United States)

    Moura, A. E.; Montenegro, S. M.; Silva, B. B.; Bartlett, M. S.; Porporato, A. M.; Antonino, A. C.

    2013-12-01

    Quantifying the effects of land use change and rainfall variability in seasonal, dry ecosystems is crucial to sustainable management of soil and water resources. In particular, changes in rainfall interception effects on hydrologic partitioning and soil erosion due to land use change are among the least known processes, despite their importance for water resource managements, in terms of water availability for ecosystem and society and water quality and erosion problems. In this work we quantify the interception losses in different types of vegetation (coffee, lemon and vegetation of natural forest) found in the Tapacurá basin in the Pernambuco state of NE Brazil, coupling field experiments and analytical models. The interception losses were measured with rain gauges installed in three types of vegetation along with stemflow collectors. Close to the coffee plantation, a meteorological station was also installed for measurement of the necessary variables for the model calibrations. As expected, the results show that rainfall events of smaller magnitude proportionally have larger relative interception losses, with larger differences in the wet season. The model results also allow us to quantify the nonlinear behavior of the interception process, at the same time providing a valuable tool to estimate the interception loss due to changes in vegetation and rainfall regime and thus to improve water resource management in seasonally dry tropics .

  7. UNDERGROUND AIR DUCT TO CONTROL RISING MOISTURE IN HISTORIC BUILDINGS: IMPROVED DESIGN AND ITS DRYING EFFICIENCY

    Directory of Open Access Journals (Sweden)

    Jiří Pazderka

    2017-10-01

    Full Text Available The underground air ducts along peripheral walls of a building are a remediation method, which principle is to enable an air flow along the moist building structure’s surface to allow a sufficient evaporation of moisture from the structure. This measure reduces the water transport (rising moisture into the higher parts of the wall where the high water content in masonry is undesirable. Presently, underground air ducts are designed as masonry structures, which durability in contact with ground moisture is limited. The article describes a new design of an underground air duct, which is based on specially shaped concrete blocks (without wet processes, because the blocks are completely precast. The air duct from concrete blocks is situated completely below the ground surface (exterior or below the floor (interior. Thanks to this, the system is invisible and does not disturb the authentic look of rehabilitated historic buildings. The efficiency of the air duct technical solution was verified by the results of tests (based on the measured moisture values conducted on a laboratory model. The experimental study showed that the moisture in the masonry equipped with the presented underground air duct had decreased considerably compared to the reference sample, namely by 43 % on average. The experimental study was numerically validated through numerical simulations performed with the program WUFI 2D.

  8. High accuracy measurements of dry mole fractions of carbon dioxide and methane in humid air

    Directory of Open Access Journals (Sweden)

    C. W. Rella

    2013-03-01

    Full Text Available Traditional techniques for measuring the mole fractions of greenhouse gases in the well-mixed atmosphere have required dry sample gas streams (dew point inter-laboratory compatibility goals (WMO, 2011a without drying the sample gas. In this paper, we present laboratory methodology for empirically deriving the water vapour correction factors, and we summarise a series of in-situ validation experiments comparing the measurements in humid gas streams to well-characterised dry-gas measurements. By using the manufacturer-supplied correction factors, the dry-mole fraction measurements have been demonstrated to be well within the GAW compatibility goals up to a water vapour concentration of at least 1%. By determining the correction factors for individual instruments once at the start of life, this water vapour concentration range can be extended to at least 2% over the life of the instrument, and if the correction factors are determined periodically over time, the evidence suggests that this range can be extended up to and even above 4% water vapour concentrations.

  9. Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.

    Science.gov (United States)

    William T. Simpson; Xiping. Wang

    2003-01-01

    Because dense stands of softwood trees are causing forest health problems in the western United States, new ways to use this material need to be found. One option is to use this material as logs rather than sawing it into lumber. For many applications, logs require some degree of drying. Even though these logs may be considered small diameter, they are large compared...

  10. A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air

    International Nuclear Information System (INIS)

    Zhang Yuzhong; Deng Shuxing; Liu Yanan; Shen Guofeng; Li Xiqing; Cao Jun; Wang Xilong; Reid, Brian; Tao Shu

    2011-01-01

    Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAH LMW4 ) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAH LMW4 within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. - Research highlights: → Design, field test and calibration of the novel passive air sampler, PAS-V-I. → Vertical concentration gradients of PAH LMW4 within a thin layer close to soil. → Comparison of results between PAS-V-I measurement and fugacity approach. → Potential application of PAS-V-I and further modifications. - A novel passive sampling device was developed and tested for measuring vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air.

  11. High accuracy measurements of dry mole fractions of carbon dioxide and methane in humid air

    Science.gov (United States)

    Rella, C. W.; Chen, H.; Andrews, A. E.; Filges, A.; Gerbig, C.; Hatakka, J.; Karion, A.; Miles, N. L.; Richardson, S. J.; Steinbacher, M.; Sweeney, C.; Wastine, B.; Zellweger, C.

    2013-03-01

    Traditional techniques for measuring the mole fractions of greenhouse gases in the well-mixed atmosphere have required dry sample gas streams (dew point < -25 °C) to achieve the inter-laboratory compatibility goals set forth by the Global Atmosphere Watch programme of the World Meteorological Organisation (WMO/GAW) for carbon dioxide (±0.1 ppm in the Northern Hemisphere and ±0.05 ppm in the Southern Hemisphere) and methane (±2 ppb). Drying the sample gas to low levels of water vapour can be expensive, time-consuming, and/or problematic, especially at remote sites where access is difficult. Recent advances in optical measurement techniques, in particular cavity ring down spectroscopy, have led to the development of greenhouse gas analysers capable of simultaneous measurements of carbon dioxide, methane and water vapour. Unlike many older technologies, which can suffer from significant uncorrected interference from water vapour, these instruments permit accurate and precise greenhouse gas measurements that can meet the WMO/GAW inter-laboratory compatibility goals (WMO, 2011a) without drying the sample gas. In this paper, we present laboratory methodology for empirically deriving the water vapour correction factors, and we summarise a series of in-situ validation experiments comparing the measurements in humid gas streams to well-characterised dry-gas measurements. By using the manufacturer-supplied correction factors, the dry-mole fraction measurements have been demonstrated to be well within the GAW compatibility goals up to a water vapour concentration of at least 1%. By determining the correction factors for individual instruments once at the start of life, this water vapour concentration range can be extended to at least 2% over the life of the instrument, and if the correction factors are determined periodically over time, the evidence suggests that this range can be extended up to and even above 4% water vapour concentrations.

  12. A comparison of measured and calculated values of air kerma rates from 137Cs in soil

    Directory of Open Access Journals (Sweden)

    V. P. Ramzaev

    2015-01-01

    Full Text Available In 2010, a study was conducted to determine the air gamma dose rate from 137Cs deposited in soil. The gamma dose rate measurements and soil sampling were performed at 30 reference plots from the south-west districts of the Bryansk region (Russia that had been heavily contaminated as a result of the Chernobyl accident. The 137Cs inventory in the top 20 cm of soil ranged from 260 kBq m–2 to 2800 kBq m–2. Vertical distributions of 137Cs in soil cores (6 samples per a plot were determined after their sectioning into ten horizontal layers of 2 cm thickness. The vertical distributions of 137Cs in soil were employed to calculate air kerma rates, K, using two independent methods proposed by Saito and Jacob [Radiat. Prot. Dosimetry, 1995, Vol. 58, P. 29–45] and Golikov et al. [Contaminated Forests– Recent Developments in Risk Identification and Future Perspective. Kluwer Academic Publishers, 1999. – P. 333–341]. A very good coincidence between the methods was observed (Spearman’s rank coefficient of correlation = 0.952; P<0.01; on average, a difference between the kerma rates calculated with two methods did not exceed 3%. The calculated air kerma rates agreed with the measured dose rates in air very well (Spearman’s coefficient of correlation = 0.952; P<0.01. For large grassland plots (n=19, the measured dose rates were on average 6% less than the calculated kerma rates. The tested methods for calculating the air dose rate from 137Cs in soil can be recommended for practical studies in radiology and radioecology. 

  13. Inhibition of water uptake after dry storage of cut flowers: Role of aspired air and wound-induced processes in Chrysanthemum

    NARCIS (Netherlands)

    Meeteren, van U.; Arévalo-Galarza, L.; Doorn, van W.G.

    2006-01-01

    We investigated the relative role of aspired air and a plant-induced reaction in the vascular occlusion of dry-stored cv. Cassa chrysanthemum flowers (Chrysanthemum × morifolium Ramat). Measurements of hydraulic capacity showed that the air that is aspired directly after cutting (into the opened

  14. Increases in soil water content after the mortality of non-native trees in oceanic island forest ecosystems are due to reduced water loss during dry periods.

    Science.gov (United States)

    Hata, Kenji; Kawakami, Kazuto; Kachi, Naoki

    2016-03-01

    The control of dominant, non-native trees can alter the water balance of soils in forest ecosystems via hydrological processes, which results in changes in soil water environments. To test this idea, we evaluated the effects of the mortality of an invasive tree, Casuarina equisetifolia Forst., on the water content of surface soils on the Ogasawara Islands, subtropical islands in the northwestern Pacific Ocean, using a manipulative herbicide experiment. Temporal changes in volumetric water content of surface soils at 6 cm depth at sites where all trees of C. equisetifolia were killed by herbicide were compared with those of adjacent control sites before and after their mortality with consideration of the amount of precipitation. In addition, the rate of decrease in the soil water content during dry periods and the rate of increase in the soil water content during rainfall periods were compared between herbicide and control sites. Soil water content at sites treated with herbicide was significantly higher after treatment than soil water content at control sites during the same period. Differences between initial and minimum values of soil water content at the herbicide sites during the drying events were significantly lower than the corresponding differences in the control quadrats. During rainfall periods, both initial and maximum values of soil water contents in the herbicided quadrats were higher, and differences between the maximum and initial values did not differ between the herbicided and control quadrats. Our results indicated that the mortality of non-native trees from forest ecosystems increased water content of surface soils, due primarily to a slower rate of decrease in soil water content during dry periods. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Short-term impact of dry olive mill residue addition to soil on the resident microbiota

    Czech Academy of Sciences Publication Activity Database

    Sampedro, I.; Giubilei, M. A.; Cajthaml, Tomáš; Federici, E.; Federici, F.; Petruccioli, M.; D´Annibale, A.

    2009-01-01

    Roč. 100, č. 23 (2009), s. 6098-6106 ISSN 0960-8524 R&D Projects: GA MŠk LC06066 Institutional research plan: CEZ:AV0Z50200510 Keywords : Dry olive mill residue * Microbial community profiling * Toxicity Subject RIV: EE - Microbiology, Virology Impact factor: 4.253, year: 2009

  16. Vertical profile measurements of soil air suggest immobilization of gaseous elemental mercury in mineral soil.

    Science.gov (United States)

    Obrist, Daniel; Pokharel, Ashok K; Moore, Christopher

    2014-02-18

    Evasion of gaseous elemental Hg (Hg(0)g) from soil surfaces is an important source of atmospheric Hg, but the volatility and solid-gas phase partitioning of Hg(0) within soils is poorly understood. We developed a novel system to continuously measure Hg(0)g concentrations in soil pores at multiple depths and locations, and present a total of 297 days of measurements spanning 14 months in two forests in the Sierra Nevada mountains, California, U.S. Temporal patterns showed consistent pore Hg(0)g concentrations below levels measured in the atmosphere (termed Hg(0)g immobilization), ranging from 66 to 94% below atmospheric concentrations throughout multiple seasons. The lowest pore Hg(0)g concentrations were observed in the deepest soil layers (40 cm), but significant immobilization was already present in the top 7 cm. In the absence of sinks or sources, pore Hg(0)g levels would be in equilibrium with atmospheric concentrations due to the porous nature of the soil matrix and gas diffusion. Therefore, we explain decreases in pore Hg(0)g in mineral soils below atmospheric concentrations--or below levels found in upper soils as observed in previous studies--with the presence of an Hg(0)g sink in mineral soils possibly related to Hg(0)g oxidation or other processes such as sorption or dissolution in soil water. Surface chamber measurements showing daytime Hg(0)g emissions and nighttime Hg(0)g deposition indicate that near-surface layers likely dominate net atmospheric Hg(0)g exchange resulting in typical diurnal cycles due to photochemcial reduction at the surface and possibly Hg(0)g evasion from litter layers. In contrast, mineral soils seem to be decoupled from this surface exchange, showing consistent Hg(0)g uptake and downward redistribution--although our calculations indicate these fluxes to be minor compared to other mass fluxes. A major implication is that once Hg is incorporated into mineral soils, it may be unlikely subjected to renewed Hg(0)g re-emission from

  17. Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid.

    Science.gov (United States)

    Padgett, Pamela E; Parry, Sally D; Bytnerowicz, Andrzej; Heath, Robert L

    2009-01-01

    Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric acid follow? We investigated the effects of dry deposition of nitric acid on the foliage of four tree species native to the western United States. A novel controlled environment, fumigation system enabled a four-week exposure at concentrations consistent with ambient diurnal patterns. Scanning electron microscopy and automated image analysis revealed changes in the epicuticular wax layer during fumigation. Exposure to nitric acid resulted in a reproducible suite of damage symptoms that increased with increasing dose. Each tree species tested exhibited a unique set of damage features, including cracks, lesions, and conformation changes to epicuticular crystallite structures. Dry deposition of atmospheric nitric acid caused substantial perturbation to the epicuticular surface of all four tree species investigated, consistent with the chemical oxidation of epicuticular waxes. Automated image analysis eliminated many biases that can trouble microscopy studies. Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.

  18. Ozone generation by negative direct current corona discharges in dry air fed coaxial wire-cylinder reactors

    International Nuclear Information System (INIS)

    Yehia, Ashraf; Mizuno, Akira

    2013-01-01

    An analytical study was made in this paper for calculating the ozone generation by negative dc corona discharges. The corona discharges were formed in a coaxial wire-cylinder reactor. The reactor was fed by dry air flowing with constant rates at atmospheric pressure and room temperature, and stressed by a negative dc voltage. The current-voltage characteristics of the negative dc corona discharges formed inside the reactor were measured in parallel with concentration of the generated ozone under different operating conditions. An empirical equation was derived from the experimental results for calculating the ozone concentration generated inside the reactor. The results, that have been recalculated by using the derived equation, have agreed with the experimental results over the whole range of the investigated parameters, except in the saturation range for the ozone concentration. Therefore, the derived equation represents a suitable criterion for expecting the ozone concentration generated by negative dc corona discharges in dry air fed coaxial wire-cylinder reactors under any operating conditions in range of the investigated parameters.

  19. Air sparging/high vacuum extraction to remove chlorinated solvents in groundwater and soil

    International Nuclear Information System (INIS)

    Phelan, J.M.; Gilliat, M.D.

    1998-01-01

    An air sparging and high vacuum extraction was installed as an alternative to a containment pump and treat system to reduce the long-term remediation schedule. The site is located at the DOE Mound facility in Miamisburg, Ohio, just south of Dayton. The air sparging system consists of 23 wells interspersed between 17 soil vapor extraction wells. The SVE system has extracted about 1,500 lbs of VOCs in five months. The air sparging system operated for about 6 weeks before shutdown due to suspected biochemical fouling. Technical data are presented on the operating characteristics of the system

  20. Detection of Bacillus anthracis in the air, soil and animal tissue

    Directory of Open Access Journals (Sweden)

    Kušar D.

    2012-01-01

    Full Text Available The objective of the present work was to establish effective and rapid diagnostic methods for the detection of Bacillus anthracis, a highly virulent zoonotic pathogen, in the air, soil and animal (or human tissue samples. Liquid culture of B. anthracis was aerosolized and four air sampling procedures were employed. Detection of B. anthracis in the air samples was successful with RCS High Flow sampler (culturebased detection and when sampling through the air filter (molecular detection using SmartHelix Complex Samples DNA Extraction Kit. Liquid B. anthracis culture was also employed for spiking the homogenised bovine lymphatic gland tissue and soil samples. DNA extraction was performed using three different commercial kits for each sample type. High Pure PCR Template Preparation Kit was the most effective for DNA extraction from animal tissue samples. Detection in the soil was successful when PowerSoil DNA Isolation Kit was used. Our results indicate that B. anthracis can be monitored in different matrices by rapid molecular methods when appropriate sampling and DNA extraction procedures are employed prior to PCR assay. The selected rapid protocols can be implemented in specialized veterinary or human diagnostic laboratories with moderate costs.

  1. Presence of Fusarium spp. in air and soil associated with sorghum fields

    Science.gov (United States)

    Sorghum grain, valuable for feed, food and bioenergy, can be colonized by several Fusarium species; therefore, it was of interest to identify possible sources of conidia. Analysis of air and soil samples provided evidence for the presence of propagules from Fusarium genotypes that may cause grain in...

  2. Effects of experimental warming of air, soil and permafrost on carbon balance in Alaskan tundra

    Science.gov (United States)

    S.M. Natali; E.A.G. Schuur; C. Trucco; C.E. Hicks Pries; K.G. Crummer; A.F. Baron Lopez

    2011-01-01

    The carbon (C) storage capacity of northern latitude ecosystems may diminish as warming air temperatures increase permafrost thaw and stimulate decomposition of previously frozen soil organic C. However, warming may also enhance plant growth so that photosynthetic carbon dioxide (C02) uptake may, in part, offset respiratory losses. To determine...

  3. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus)

    DEFF Research Database (Denmark)

    Mikes, Ondrej; Cupr, P.; Trapp, Stefan

    2009-01-01

    Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for beta-hexachlorocyclohexane. Bioconcentration factor (BCF, def...

  4. Air exposure induced characteristics of dry eye in conjunctival tissue culture.

    Directory of Open Access Journals (Sweden)

    Hui Lin

    Full Text Available There are several animal models illustrating dry eye pathophysiology. Current study would like to establish an ex vivo tissue culture model for characterizing dry eye. Human conjunctival explants were cultured under airlift or submerged conditions for up to 2 weeks, and only airlifted conjunctival cultures underwent increased epithelial stratification. Starting on day 4, the suprabasal cells displayed decreased K19 expression whereas K10 keratin became evident in airlift group. Pax6 nuclear expression attenuated already at 2 days, while its perinuclear and cytoplasmic expression gradually increased. MUC5AC and MUC19 expression dramatically decreased whereas the full thickness MUC4 and MUC16 expression pattern disappeared soon after initiating the airlift condition. Real time PCR showed K16, K10 and MUC16 gene up-regulated while K19, MUC5AC, MUC19 and MUC4 down-regulated on day 8 and day 14. On day 2 was the appearance of apoptotic epithelial and stromal cells appeared. The Wnt signaling pathway was transiently activated from day 2 to day 10. The inflammatory mediators IL-1β, TNF-α, and MMP-9 were detected in the conditioned media after 6 to 8 days. In conclusion, airlifted conjunctival tissue cultures demonstrated Wnt signaling pathway activation, coupled with squamous metaplasia, mucin pattern alteration, apoptosis and upregulation of proinflammatory cytokine expression. These changes mimic the pathohistological alterations described in dry eye. This correspondence suggests that insight into the pathophysiology of dry eye may be aided through the use of airlifted conjunctival tissue cultures.

  5. Effect of periodic wetting and drying on selective sorption of 137Cs by mixtures of soil and organomineral sorbent

    Science.gov (United States)

    Popov, V. E.; Maslova, K. M.; Stepina, I. A.

    2014-05-01

    The incubation of sandy soddy-podzolic soil with a three-component organomineral sorbent (OMS) on the basis of sapropel, neutralized hydrolysis lignin, and clay-salt slime under alternating wetting-drying (W-D) conditions for two years has increased the selective sorption of 137Cs by 2.5-5 times. The addition of 5% OMS increases the effect of periodic W-D cycles on the selective sorption of 137Cs compared to the addition of 10% OMS. The relationship between the 137Cs interception potential and the number of W-D cycles has been predicted on the basis of the additivity rule and under the assumption that this potential linearly depends on the number of W-D cycles. The predicted values of the 137Cs interception potential almost coincide with the experimental data for the mixtures of sandy soddy-podzolic soil with 10% OMS and are lower than the experimental values by 60% for the mixtures of soil with 10% OMS.

  6. Air pollution: Household soiling and consumer welfare losses

    Science.gov (United States)

    Watson, W.D.; Jaksch, J.A.

    1982-01-01

    This paper uses demand and supply functions for cleanliness to estimate household benefits from reduced particulate matter soiling. A demand curve for household cleanliness is estimated, based upon the assumption that households prefer more cleanliness to less. Empirical coefficients, related to particulate pollution levels, for shifting the cleanliness supply curve, are taken from available studies. Consumer welfare gains, aggregated across 123 SMSAs, from achieving the Federal primary particulate standard, are estimated to range from $0.9 to $3.2 million per year (1971 dollars). ?? 1982.

  7. Effect of biochar addition on short-term N2O and CO2 emissions during repeated drying and wetting of an anthropogenic alluvial soil.

    Science.gov (United States)

    Yang, Fang; Lee, Xinqing; Theng, Benny K G; Wang, Bing; Cheng, Jianzhong; Wang, Qian

    2017-06-01

    Agricultural soils are an important source of greenhouse gases (GHG). Biochar application to such soils has the potential of mitigating global anthropogenic GHG emissions. Under irrigation, the topsoils in arid regions experience repeated drying and wetting during the crop growing season. Biochar incorporation into these soils would change the soil microbial environment and hence affect GHG emissions. Little information, however, is available regarding the effect of biochar addition on carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) emissions from agricultural soils undergoing repeated drying and wetting. Here, we report the results of a 49-day aerobic incubation experiment, incorporating biochar into an anthropogenic alluvial soil in an arid region of Xinjiang Province, China, and measuring CO 2 and N 2 O emissions. Under both drying-wetting and constantly moist conditions, biochar amendment significantly increased cumulative CO 2 emission. At the same time, there was a significant reduction (up to ~20 %) in cumulative N 2 O emission, indicating that the addition of biochar to irrigated agricultural soils may effectively slow down global warming in arid regions of China.

  8. Research on Wetting-Drying Cycles’ Effect on the Physical and Mechanical Properties of Expansive Soil Improved by OTAC-KCl

    Directory of Open Access Journals (Sweden)

    Bao-tian Wang

    2015-01-01

    Full Text Available Expansive soil experiences periodic swelling and shrinkage during the alternate wet and dry environments, which will result in severe damage to the slope stability. In this study, a promising modifier OTAC-KCl is introduced, which has a good diffusivity and is soluble in water or other solvents easily. Firstly, a reasonable combination of ameliorant 0.3% STAC and 3% KCl is chosen referring to the free swell test. Then, the best curing period, 14 days, is gotten from UCS tests. The effect of wetting and drying cycles on engineering properties of expansive soil improved by OTAC-KCl admixtures after 14-day curing is also studied accordingly. Both treated and untreated expansive soil samples are prepared for the cyclic wetting-drying tests which mainly include cyclic swelling potential and cyclic strength tests. Experimental results show that the swelling potential of expansive soil samples stabilized with OTAC-KCl is suppressed efficiently, and the untreated soil specimens will collapse when immersed in water while the treated specimens keep in good conditions. Moreover, expansive soil samples modified with 0.3% OTAC + 3% KCl show enough durability on the swelling ability, shear strength, and unconfined compressive strength, which means, that both the physical and the mechanical properties of stabilized expansive soil have been improved effectively.

  9. HVAC--the importance of clean intake section and dry air filter in cold climate.

    Science.gov (United States)

    Hanssen, S O

    2004-01-01

    HVAC systems, if properly designed, installed, operated and maintained, will improve thermal conditions and air quality indoors. However, the success strongly depends on the design of the system and the quality of the components we use in our HVAC installations. Regrettably, several investigations have revealed that many HVAC installations have a lot of operational and maintenance problems, especially related to moisture, rain and snow entrainment. In short, it seems that too little attention is placed on the design of the intake section, despite the fact that there exists a large number of national and international guidelines and recommendations. This is a serious problem because the air intake is the initial component of the ventilation plant and as such the first line of defense against debris and other outdoor air pollutants. Unfortunately, the design is often an argued compromise between the architect, the civil engineer and the HVAC engineer. In the future, the technical, hygienic and microbiological feature of air intakes must be better ensured in order to avoid the air intake becoming a risk component as regards contamination and indoor air quality. Further, it seems that the magnitude of the problem is not well known, or recognized, by the building designers, engineers and professionals involved in the construction and operation of buildings. This fact needs to be addressed more seriously, because obviously there is a big difference between the idealistic architectonic design, engineering intentions and the real life situation. Several practical recommendations for design and operation of HVAC systems are presented. Following the recommendations will result in less pollution from the HVAC-system and increased indoor environmental quality.

  10. Dried gamma-irradiated sewage solids use on calcareous soils: crop yeilds and heavy metals uptake

    International Nuclear Information System (INIS)

    McCaslin, B.D.; Sivinski, J.S.

    1979-01-01

    Experiments designed to examine gamma-radiation effects on extractable and plant-available sludge elements and to examine the response of crops to sludge applications on two typical, calcareous soils in New Mexico are summarized. Information has been given indicating that the radiation process of reducing pathogens in sewage products being developed by Sandia Laboratories, does not significantly increase the chemical extractability and plant uptake of a broad range of nutrients and heavy metals. However, radiation treatment greatly facilitates handling sewage for experimentation, because pathogen contamination precautions are eliminated and weed seeds killed. Studies on the effects of sludge irradiation on plant nutrient uptake revealed no concentration increases, agreeing with results presented herein. Sewage products may have special potential for use on calcareous soils, such as in New Mexico. For instance, in New Mexico the lack of potassium in sewage products is not a problem and the naturally high pH of New Mexico soil greatly reduces plant availability of many problem heavy metals. Dramatic increases in yield are typified by the greenhouse and field results presented herein, especially for the known micronutrient deficient soils of New Mexico. Results indicate that sewage sludge is an excellent Zn and Fe fertilizer. More research needs to be done before the economics of sludge application can be calculated and more field information is needed before irradiated sewage products are used indiscriminately

  11. Impact of mechanized logging operations on wet and dry soils of ...

    African Journals Online (AJOL)

    Mechanization of timber harvesting operations in Tanzania involves use of machinery such as feller bunchers, skidders and tractors which are generally heavy in weight ranging from 12 to 16 tones in unloaded state. The movements of these machines induce soil compaction owing to the exerted normal pressure, vibrations ...

  12. Dried gamma-irradiated sewage solids use on calcareous soils: crop yeilds and heavy metals uptake

    Energy Technology Data Exchange (ETDEWEB)

    McCaslin, B.D.; Sivinski, J.S.

    1979-01-01

    Experiments designed to examine gamma-radiation effects on extractable and plant-available sludge elements and to examine the response of crops to sludge applications on two typical, calcareous soils in New Mexico are summarized. Information has been given indicating that the radiation process of reducing pathogens in sewage products being developed by Sandia Laboratories, does not significantly increase the chemical extractability and plant uptake of a broad range of nutrients and heavy metals. However, radiation treatment greatly facilitates handling sewage for experimentation, because pathogen contamination precautions are eliminated and weed seeds killed. Studies on the effects of sludge irradiation on plant nutrient uptake revealed no concentration increases, agreeing with results presented herein. Sewage products may have special potential for use on calcareous soils, such as in New Mexico. For instance, in New Mexico the lack of potassium in sewage products is not a problem and the naturally high pH of New Mexico soil greatly reduces plant availability of many problem heavy metals. Dramatic increases in yield are typified by the greenhouse and field results presented herein, especially for the known micronutrient deficient soils of New Mexico. Results indicate that sewage sludge is an excellent Zn and Fe fertilizer. More research needs to be done before the economics of sludge application can be calculated and more field information is needed before irradiated sewage products are used indiscriminately. (ERB)

  13. Drivers of soil drying in the Czech Republic between 1961 and 2012

    Czech Academy of Sciences Publication Activity Database

    Trnka, M.; Brázdil, R.; Balek, J.; Semerádová, D.; Hlavinka, P.; Možný, M.; Štepánek, P.; Dobrovolný, P.; Zahradníček, P.; Dubrovský, Martin; Eitzinger, J.; Fuchs, B.; Svoboda, M.; Hayes, M.; Žalud, Z.

    2015-01-01

    Roč. 35, č. 9 (2015), s. 2664-2675 ISSN 0899-8418 Institutional support: RVO:68378289 Keywords : pan evaporation * soil moisture * reference evapotranspiration * drought climatology * water balance * observed climate change Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.609, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/joc.4167/abstract

  14. Bryoid layer response to soil disturbance by fuel reduction treatments in a dry conifer forest

    Science.gov (United States)

    Amanda Hardman; Bruce McCune

    2010-01-01

    We investigated the response of the bryoid layer, bryophyte and lichen communities on the soil surface three years after fuel reduction treatment (logging and burning) in the central Blue Mountains of eastern Oregon. Both treatment and control areas had been decimated by spruce budworm and drought before the fuel reduction treatments. Treatments reduced overstory and...

  15. Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

    Directory of Open Access Journals (Sweden)

    Samuel Enahoro Agarry

    2017-01-01

    Full Text Available The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h and 1.67-7 h, respectively at temperature ranging from 75 to 35oC. The drying of red pepper and bitter leaf was both in the constant and falling rate period. Four semi-empirical mathematical drying models (Newton, Page, Henderson and Pabis, and Logarithmic models were fitted to the experimental drying curves. The models were compared using the coefficient of determination (R^2 and the root mean square error (RMSE. The Page model has shown a better fit to the experimental drying data of red pepper and bitter leaf, respectively as relatively compared to other tested models. Moisture transport during drying was described by the application of Fick’s diffusion model and the effective moisture diffusivity was estimated. The value ranges from 15.69 to 84.79 × 10-9 m2/s and 0.294 to 1.263 × 10-9 m2/s for red pepper and bitter leaf, respectively. The Arrhenius-type relationship describes the temperature dependence of effective moisture diffusivity and was determined to be 37.11 kJ/mol and 32.86 kJ/mol for red pepper and bitter leaf, respectively. A correlation between the drying time and the heat transfer area was also developed.

  16. Mathematical models and qualities of shredded Thai-style instant rice under a combined gas-fired infrared and air convection drying

    Science.gov (United States)

    Nachaisin, Mali; Teeta, Suminya; Deejing, Konlayut; Pharanat, Wanida

    2017-09-01

    Instant food is a product produced for convenience for consumer. Qualities are an important attribute of food materials reflecting consumer acceptance. The most problem of instant rice is casehardening during drying process resulted in the longer rehydration time. The objective of this research was to study the qualities of shredded Thai-style instant rice under a combined gas-fired infrared and air convection drying. Additionally, the mathematical models for gas-fired infrared assisted thin-layer drying of shredded Thai-style rice for traditional was investigated. The thin-layer drying of shredded Thai-style rice was carried out under gas-fired infrared intensities of 1000W/m2, air temperatures of 70°C and air velocities of 1 m/s. The drying occurred in the falling rate of drying period. The Page model was found to satisfactorily describe the drying behavior of shredded Thai-style rice, providing the highest R2 (0.997) and the lowest MBE and RMSE (0.01 and 0.18) respectively. A 9 point hedonic test showed in softness and color, but odor and overall acceptance were very similar.

  17. Antioxidant N-acetyltransferase Mpr1/2 of industrial baker's yeast enhances fermentation ability after air-drying stress in bread dough.

    Science.gov (United States)

    Sasano, Yu; Takahashi, Shunsuke; Shima, Jun; Takagi, Hiroshi

    2010-03-31

    During bread-making processes, yeast cells are exposed to multiple stresses. Air-drying stress is one of the most harmful stresses by generation of reactive oxygen species (ROS). Previously, we discovered that the novel N-acetyltransferase Mpr1/2 confers oxidative stress tolerance by reducing intracellular ROS level in Saccharomyces cerevisiae Sigma1278b strain. In this study, we revealed that Japanese industrial baker's yeast possesses one MPR gene. The nucleotide sequence of the MPR gene in industrial baker's yeast was identical to the MPR2 gene in Sigma1278b strain. Gene disruption analysis showed that the MPR2 gene in industrial baker's yeast is involved in air-drying stress tolerance by reducing the intracellular oxidation levels. We also found that expression of the Lys63Arg and Phe65Leu variants with enhanced enzymatic activity and stability, respectively, increased the fermentation ability of bread dough after exposure to air-drying stress compared with the wild-type Mpr1. In addition, our recent study showed that industrial baker's yeast cells accumulating proline exhibited enhanced freeze tolerance in bread dough. Proline accumulation also enhanced the fermentation ability after air-drying stress treatment in industrial baker's yeast. Hence, the antioxidant enzyme Mpr1/2 could be promising for breeding novel yeast strains that are tolerant to air-drying stress. Copyright 2010 Elsevier B.V. All rights reserved.

  18. Observed trends of soil fauna in the Antarctic Dry Valleys: early signs of shifts predicted under climate change.

    Science.gov (United States)

    Andriuzzi, W S; Adams, B J; Barrett, J E; Virginia, R A; Wall, D H

    2018-02-01

    Long-term observations of ecological communities are necessary for generating and testing predictions of ecosystem responses to climate change. We investigated temporal trends and spatial patterns of soil fauna along similar environmental gradients in three sites of the McMurdo Dry Valleys, Antarctica, spanning two distinct climatic phases: a decadal cooling trend from the early 1990s through the austral summer of February 2001, followed by a shift to the current trend of warming summers and more frequent discrete warming events. After February 2001, we observed a decline in the dominant species (the nematode Scottnema lindsayae) and increased abundance and expanded distribution of less common taxa (rotifers, tardigrades, and other nematode species). Such diverging responses have resulted in slightly greater evenness and spatial homogeneity of taxa. However, total abundance of soil fauna appears to be declining, as positive trends of the less common species so far have not compensated for the declining numbers of the dominant species. Interannual variation in the proportion of juveniles in the dominant species was consistent across sites, whereas trends in abundance varied more. Structural equation modeling supports the hypothesis that the observed biological trends arose from dissimilar responses by dominant and less common species to pulses of water availability resulting from enhanced ice melt. No direct effects of mean summer temperature were found, but there is evidence of indirect effects via its weak but significant positive relationship with soil moisture. Our findings show that combining an understanding of species responses to environmental change with long-term observations in the field can provide a context for validating and refining predictions of ecological trends in the abundance and diversity of soil fauna. © 2018 by the Ecological Society of America.

  19. The dependence of water potential in shoots of Picea abies on air and soil water status

    Directory of Open Access Journals (Sweden)

    A. Sellin

    Full Text Available Where there is sufficient water storage in the soil the water potential (Ψx in shoots of Norway spruce [Picea abies (L. Karst.] is strongly governed by the vapour pressure deficit of the atmosphere, while the mean minimum values of Ψx usually do not drop below –1.5 MPa under meteorological conditions in Estonia. If the base water potential (Ψb is above –0.62 MPa, the principal factor causing water deficiency in shoots of P. abies may be either limited soil water reserves or atmospheric evaporative demand depending on the current level of the vapour pressure deficit. As the soil dries the stomatal control becomes more efficient in preventing water losses from the foliage, and the leaf water status, in turn, less sensitive to atmospheric demand. Under drought conditions, if Ψb falls below –0.62 MPa, the trees' water stress is mainly caused by low soil water availability. Further declines in the shoot water potential (below –1.5 MPa can be attributed primarily to further decreases in the soil water, i.e. to the static water stress.Key words. Hydrology (evapotranspiration · plant ecology · soil moisture.

  20. Metal concentration in urban park soils of Sao Paulo 2. Buenos AiresPark

    International Nuclear Information System (INIS)

    Gumiero, Felipe C.; Figueiredo, Ana Maria G.; Camargo, Sonia P.; Pavese, Arthur; Sigolo, Joel B.

    2007-01-01

    As part of a project which aims metal concentration assessment in urban park soils of Sao Paulo, in the present paper the concentration of the elements As, Ba, Cr, Co, Cu, Pb, Sb and Zn were determined in surface soil samples (0-5 cm and 0-20 cm) from Buenos Aires park of Sao Paulo. This park is located in central region of the city, and is surrounded by avenues and streets, with different traffic volumes. Instrumental Neutron Activation Analysis (INAA) and X-ray Fluorescence (FRX) were used for metal analysis. Preliminary results showed concentration levels of the analyzed elements higher than the values considered as reference values for soils in Sao Paulo, according to the Environmental Protection Agency of the State of Sao Paulo (CETESB). These results suggest that these elements have anthropogenic origin and indicate a potential risk for soil quality. (author)

  1. Soil microarthropods are only weakly impacted after 13 years of repeated drought treatment in wet and dry heathland soils

    DEFF Research Database (Denmark)

    Holmstrup, Martin; Sørensen, Jesper G.; Schmidt, Inger Kappel

    2013-01-01

    Studies of biological responses in the terrestrial environment to rapid changes in climate have mostly been concerned with aboveground biota, whereas less is known of belowground organisms. The present study focuses on mites and springtails of heathland ecosystems and how the microarthropod...... and temperature. This approach provided an opportunity to study biological responses on a local (within sites) and regional scale. Warming treatments increasing night time temperature (0.3–1 °C higher than ambient at 5 cm soil depth) had no detectable effects on the microarthropod communities. Increased intensity...... and frequency of drought had only weak persistent effects on springtail species composition, but practically no effect on major mite groups (Oribatida, Prostigmata or Mesostigmata) suggesting that ecosystem functions of microarthropods may only be transiently impacted by repeated spring or summer drought....

  2. Novel Approach for the Remediation of Radioactive Cesium Contaminated Soil with nano-Fe/Ca/CaO Dispersion Mixture in Dry Condition

    Directory of Open Access Journals (Sweden)

    Mallampati S. R.

    2013-04-01

    Full Text Available Present study, first time we developed a nano-Fe/Ca/CaO dispersion mixture based remediation and volume reduction method of real radioactive cesium contaminated soils. After soil samples treated with 10wt% of nano-Fe/Ca/CaO dispersion mixtures, emitting radiation intensity was reduced from 4.00 μSv/h to 0.95 μSv/h in non-magnetic fraction soils. While, after treatment, about 30wt% magnetic and 70wt% nonmagnetic fraction soils were separated, and it’s condensed radioactive cesium concentration was about 80% and 20%, respectively. By this way, cesium contaminated soil volume can be reduced. These preliminary results appear to be very promising and the simple mixing with the addition of nano-Fe/Ca/CaO may be considered potentially applicable for the remediation and separation of radioactive Cs contaminated soil in dry conditions.

  3. Coupled heat and water flow dynamics in dry soils : application to a multilayer waste cover

    OpenAIRE

    Gran Esforzado, Meritxell

    2015-01-01

    Unsaturated flow plays an important role in numerous environmental phenomena. It is complex in arid regions, where liquid water fluxes are small and vapor fluxes become relevant, so that heat, water and solute mass transport are needed to understand evaporation. This thesis aims at gaining insight evaporation and vapor flow mechanisms and the relevance of matric potential, temperature and osmotic gradients. These issues are especially relevant for soil salinization, whose mechanisms are po...

  4. Polymer tensiometers with ceramic cones: direct observations of matric pressures in drying soils

    Directory of Open Access Journals (Sweden)

    M. J. van der Ploeg

    2010-10-01

    Full Text Available Measuring soil water potentials is crucial to characterize vadose zone processes. Conventional tensiometers only measure until approximately −0.09 MPa, and indirect methods may suffer from the non-uniqueness in the relationship between matric potential and measured properties. Recently developed polymer tensiometers (POTs are able to directly measure soil matric potentials until the theoretical wilting point (−1.6 MPa. By minimizing the volume of polymer solution inside the POT while maximizing the ceramic area in contact with that polymer solution, response times drop to acceptable ranges for laboratory and field conditions. Contact with the soil is drastically improved with the use of cone-shaped solid ceramics instead of flat ceramics. The comparison between measured potentials by polymer tensiometers and indirectly obtained potentials with time domain reflectometry highlights the risk of using the latter method at low water contents. By combining POT and time domain reflectometry readings in situ moisture retention curves can be measured over the range permitted by the measurement range of both POT and time domain reflectometry.

  5. Relationships between Hg Air-surface exchange, Soil Moisture and Precipitation at a Background Vegetated Site in South-Eastern Australia.

    Science.gov (United States)

    Macsween, K.; Edwards, G. C.

    2017-12-01

    Despite many decades of research, the controlling mechanisms of mercury (Hg) air-surface exhange are still poorly understood. Particularly in Australian ecosystems where there are few anthropogenic inputs. A clear understanding of these mechanisms is vital for accurate representation in the global Hg models, particularly regarding re-emission. Water is known to have a considerable influence on Hg exchange within a terrestrial ecosystem. Precipitation has been found to cause spikes is Hg emissions during the initial stages of rain event. While, Soil moisture content is known to enhance fluxes between 15 and 30% Volumetric soil water (VSW), above which fluxes become suppressed. Few field experiments exist to verify these dominantly laboratory or controlled experiments. Here we present work looking at Hg fluxes over an 8-month period at a vegetated background site. The aim of this study is to identify how changes to precipitation intensity and duration, coupled with variable soil moisture content may influence Hg flux across seasons. As well as the influence of other meteorological variables. Experimentation was undertaken using aerodynamic gradient micrometeorological flux method, avoiding disruption to the surface, soil moisture probes and rain gauge measurements to monitor alterations to substrate conditions. Meteorological and air chemistry variables were also measured concurrently throughout the duration of the study. During the study period, South-Eastern Australia experienced several intense east coast low storm systems during the Autumn and Spring months and an unusually dry winter. VSW rarely reached above 30% even following the intense rainfall experienced during the east coast lows. The generally dry conditions throughout winter resulted in an initial spike in Hg emissions when rainfall occurred. Fluxes decreased shortly after the rain began but remained slightly elevated. Given the reduced net radiation and cooler temperatures experienced during the winter

  6. Performance of artificially defected LWR fuel rods in an unlimited air dry storage atmosphere

    International Nuclear Information System (INIS)

    Einziger, R.E.; Knecht, R.L.; Cantley, D.A.; Cook, J.A.

    1983-09-01

    Thus far the tests are inconclusive as to whether breached LWR fuel can be stored at 230 0 C for long periods of time in air without fuel oxidation and dispersion. There is every indication, as expected, that there is no oxidation problem in an inert atmosphere. Only one of four defects exposed to unlimited air gave any indication of fuel oxidation. It has been suggested that this might be an incubation effect and continued operation would result in oxidation occurring at all four defects. As yet the destructive examination of the BWR rod has not been completed, so it is not possible to determine if cladding splitting was due to an anomoly in this test rod or something that can be expected in LWR rods in general. Thus far there is no indication of respirable particle dispersal even if fuel oxidation does occur

  7. Ozone production using a power modulated surface dielectric barrier discharge in dry synthetic air

    Czech Academy of Sciences Publication Activity Database

    Šimek, Milan; Pekárek, S.; Prukner, Václav

    2012-01-01

    Roč. 32, č. 4 (2012), s. 743-754 ISSN 0272-4324 R&D Projects: GA ČR(CZ) GA202/09/0176 Institutional research plan: CEZ:AV0Z20430508 Keywords : ozone * surface DBD * synthetic air * nitrogen oxides * production efficiency Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.728, year: 2012 http://www.springerlink.com/content/h7p1j46381150510/fulltext.pdf

  8. Effects of arbuscular mycorrhizal fungi and soil nutrient addition on the growth of Phragmites australis under different drying-rewetting cycles.

    Science.gov (United States)

    Liang, Jin-Feng; An, Jing; Gao, Jun-Qin; Zhang, Xiao-Ya; Yu, Fei-Hai

    2018-01-01

    The frequency of soil drying-rewetting cycles is predicted to increase under future global climate change, and arbuscular mycorrhizal fungi (AMF) are symbiotic with most plants. However, it remains unknown how AMF affect plant growth under different frequencies of soil drying-rewetting cycles. We subjected a clonal wetland plant Phragmites australis to three frequencies of drying-rewetting cycles (1, 2, or 4 cycles), two nutrient treatments (with or without), and two AMF treatments (with or without) for 64 days. AMF promoted the growth of P. australis, especially in the 2 cycles of the drying-rewetting treatment. AMF had a significant positive effect on leaf mass and number of ramets in the 2 cycles of the drying-rewetting treatment with nutrient addition. In the 2 cycles of drying-rewetting treatment without nutrient addition, AMF increased leaf area and decreased belowground to aboveground biomass ratio. These results indicate that AMF may assist P. australis in coping with medium frequency of drying-rewetting cycles, and provide theoretical guidance for predicting how wetland plants respond to future global climate change.

  9. Impact of clay mineral on air oxidation of PAH-contaminated soils.

    Science.gov (United States)

    Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

    2014-09-01

    This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2.

  10. Use of a horizontal air-dispersion system to enhance biodegradation of diesel fuel contaminated soils

    International Nuclear Information System (INIS)

    Baker, J.N.; Nickerson, D.A.; Guest, P.R.; Portele, T.E.

    1993-01-01

    A horizontal air-dispersion system was designed and installed to enhance the natural biodegradation of residual diesel fuel contaminated soils at an underground storage tank (UST) facility in Seattle, Washington. This system was designed to operate in conjunction with an existing free-product recovery system which exposes more heavily contaminated soils at the capillary fringe to injected air. Results of a pilot study conducted at the facility indicate that an initial biodegradation rate of 2,200 mg of total petroleum hydrocarbons (TPH) per kg of soil per year will be achieved, making in-situ biodegradation a feasible remedial alternative for contaminated site soils. Oxygen, carbon dioxide, and hydrocarbon vapor concentrations have been monitored since full-scale startup in September 1992, using a series of vapor monitoring points (VMPs) installed in the vicinity of the aerated beds and around the perimeter of the facility. Recent monitoring data indicate that the system is capable of aerating soils at distances greater than 80 feet from the aerated beds. Oxygen utilization and carbon dioxide production measured during post-startup respiration tests indicate microbial activity has increased as a result of seven months of full-scale system operation

  11. Numerical modeling studies on the alternately pulsed infiltration and subsequent evaporation of water in a dry high desert alluvial soil

    International Nuclear Information System (INIS)

    Cawlfield, D.E.; Lindstrom, F.T.; Weaver, H.

    1993-01-01

    The concept of no liquid-phase migration of low-level radionuclides is extremely important for the U.S. Department of Energy, Nevada Operations Office (USDOE/NV) Low-Level Radioactive Waste Management Sites (RWMS) in Areas 3 and 5 of the Nevada Test Site (NTS). Each site location is situated in an area known for its dry conditions. A series of computer modeling problems were set up to study the effects of pulsing the desert surface with large amounts of water, followed by intense evaporative conditions. The pulsed-water scenarios were run using an in-house model, named open-quotes ODRECHB,close quotes which is briefly described. ODRECHB is particularly adapted to model the dry desert alluvium and extreme evaporative conditions found at NTS. Comparable results were obtained using the well known Battelle NW code open-quotes UNSAT-H 2.0,close quotes by Fayer and Jones. The realistic-to-overly conservative water applications to a bare soil surface did not cause water to infiltrate below ten meters. The results are shown on the accompanying video tape

  12. Monitoring of the vegetable garden open air spinach and soil radioactivity in Beijing during the Japan Fukushima nuclear accident

    International Nuclear Information System (INIS)

    Zhou Qiang; Xu Cuihua; Tuo Fei; Zhang Jing; Li Wenhong; Zhang Qing; Zhang Weijun; Zhang Jianfeng; Su Xu

    2012-01-01

    Objective: To detect artificial radionuclide content in the spinach and soil in open air vegetable garden in Beijing during Fukushima nuclear accident and to study the radioactive contamination characteristics of the samples. Methods: 6 spinach samples and 3 soil samples in open air vegetable garden were obtained through continuously sampling. High-purity germanium (HPGe) γ spectrometry was used to analyze activity concentrations of artificial radionuclide 131 I etc in these samples. Results: Artificial radionuclide 131 I was detected in the 6 open air spinach samples. Artificial radionuclide 137 Cs was detected in 3 vegetable garden soil samples, trace amount of 131 I was detected in 1 open-air surface soil sample alone. Conclusions: Following the Fukushima nuclear accident, spinach in Beijing's open-air vegetable garden was slightly polluted by artificial radionuclide 131 I, with the highest values of pollution appeared around April 4, 2011, but it could not cause harm to human health. (authors)

  13. Detection of PAX8/PPARG and RET/PTC Rearrangements Is Feasible in Routine Air-Dried Fine Needle Aspiration Smears

    DEFF Research Database (Denmark)

    Ferraz, Carolina; Rehfeld, Christian; Krogdahl, Annelise

    2012-01-01

    Background: The diagnostic limitations of fine needle aspiration (FNA), like the indeterminate category, can be partially overcome by molecular analysis. As PAX8/PPARG and RET/PTC rearrangements have been detected in follicular thyroid carcinomas (FTCs) and papillary thyroid carcinomas (PTCs......), their detection in FNA smears could improve the FNA diagnosis. To date, these rearrangements have never been analyzed in routine air-dried FNA smears, but only in frozen tissue, formalin-fixed paraffin-embedded (FFPE) tissue, and in fresh FNA material. Fixed routine air-dried FNA samples have hitherto been judged...... as generally not suitable for testing these rearrangements in a clinical setting. Therefore, the objective of the present study was to investigate the feasibility of extracting RNA from routine air-dried FNA smears for the detection of these rearrangements with real-time polymerase chain reaction (RT...

  14. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    Science.gov (United States)

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications. © 2013.

  15. Nodulation, dry matter production and N2 fixation by fababean and chickpea as affected by soil moisture and potassium fertilizer

    International Nuclear Information System (INIS)

    Kurdali, F.; Al-Ain, F.; Al-Ahamma, M.

    2003-01-01

    The impact of three rates of K-fertilizer (0, 75, and 150 kg K 2 O/ha)on nodulation, dry matter production and N 2 fixation by fababean (Vicia faba L.) and chickpea (Cirer arietinum L.) was evaluated in a pot experiment. The plants were subjected to three soil moisture regimes (low, 45-50%; moderate, 55-60% and high 75-80% of field capacity). 15 N-isotope dilution method was employed to evaluate N 2 fixation using a non-fixing chickpea genotype as a reference crop. Water restriction drastically affected dry matter production, nodulation and N 2 fixation by both plant species. The negative effect of water stress on %N 2 fixed was more prominent in chickpea (11-58%) than in fababean (68-81%) under low and high % of field capacity, respectively. Plant species differed in their response to K-fertilizer as a mean to enhance growth and overcome the stress conditions. The higher level of K fertilizer increased both dry matter production and total N 2 fixed in fababean, but did not have any impact on chickpea. %N 2 fixed, however, appeared to be unaffected by K fertilizer as a mean of alleviating drought stress in both plant species. Therefore, it appears that, under the experimental conditions, the beneficial effect of potassium on water-stressed fababean resulted from stimulation the growth rather than improving the N 2 -fixation efficiency. However, under well-watered plants, a high requirement of the symbiotic system to potassium is needed to ensure and optimal growth and N 2 -fixation. (author)

  16. Measurement of radioactive soil contamination from the air

    International Nuclear Information System (INIS)

    Loman, A.C.; Kuile, C.R. ter; Slaper, H.

    1990-09-01

    In-situ gamma spectrometry can be used to determine the qualitative and quantitative deposition of radioactive materials on the ground surface. By applying the in-situ spectrometry method using either a helicopter or an airplane, large areas can be scanned in a short period of time. In this report the results of in-situ gamma spectroscopic measurements taken from a helicopter are described. Measurements were carried out using a single point source, a field of 36 point sources, and using the present ground contamination due to fall-out from the Chernobyl accident and atom bombs. The results of these measurements were used to determine calibration factors, which were in agreement with a calibration obtained using more simple (and less expensive) laboratory measurements in combination with flux calculations. Detection limits for the measurement of surface contamination were determined. At a height of 50 meters above the surface and using a measurement time of 2 minutes, the minimally detectable surface contamination was 1.1 kBqm -2 for a Cs-137 contamination and 2.1 kBqm -2 for I-131 contamination. Fall-out determinations based on measurements taken at a height of 50 meters were in agreement with determinations taken at a height of 1 meter, and with the results obtained measuring soil samples. The in-situ gamma spectroscopy, using helicopter or airplane, is a fast and powerful method for mapping surface contamination. (author). 13 refs.; 18 figs.; 13 tabs

  17. Techno-economic analysis of a roof-integrated solar air heating system for drying fruit and vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Sreekumar, A. [Dept. of Physics, Cochin University of Science and Technology, Kochi 682 022 (India)

    2010-11-15

    The solar air heater was 46 m{sup 2} and recorded a maximum temperature of 76.6 C. The dryer was loaded with 200 kg of fresh pineapple slices 5 mm thick. The initial moisture content of 82% was reduced to the desired level (<10%) within 8 h. The performance of the dryer was analyzed in detail by three methods namely annualized cost, present worth of annual savings, and present worth of cumulative savings. The cost of drying 1 kg pineapple worked out to Rs. 11 which was roughly half of that of an electric dryer. The payback period worked out to 0.54 year, much less than the estimated life of the system (20 years). (author)

  18. An economic optimization of evaporator and air collector area in a solar assisted heat pump drying system

    International Nuclear Information System (INIS)

    Rahman, S.M.A.; Saidur, R.; Hawlader, M.N.A.

    2013-01-01

    Highlights: • The optimum combination will provide around 89% of the total load. • The system has a savings during the life cycle with least payback period of 4.37 year. • The optimal system is insensitive to the variation in fuel inflation and discount rate. - Abstract: This paper presents an economic optimization of evaporator and air collector area of a solar assisted heat pump drying system. Economic viability of solar heating systems is usually made by comparing the cost flows recurring throughout the lifetime of the solar and conventional alternative systems. Therefore, identification of optimum variables by using a simulation program and an economic analysis based on payback period of the system are presented in this paper. FORTRAN language is used to run the simulation. Effect of load and different economic variables on payback period is also investigated. Economic analysis reveals that system has sufficient amount of savings during the life cycle with a minimum payback period of about 4 years

  19. Vibration and acoustic noise emitted by dry-type air-core reactors under PWM voltage excitation

    Science.gov (United States)

    Li, Jingsong; Wang, Shanming; Hong, Jianfeng; Yang, Zhanlu; Jiang, Shengqian; Xia, Shichong

    2018-05-01

    According to coupling way between the magnetic field and the structural order, structure mode is discussed by engaging finite element (FE) method and both natural frequency and modal shape for a dry-type air-core reactor (DAR) are obtained in this paper. On the basis of harmonic response analysis, electromagnetic force under PWM (Pulse Width Modulation) voltage excitation is mapped with the structure mesh, the vibration spectrum is gained and the consequences represents that the whole structure vibration predominates in the radial direction, with less axial vibration. Referring to the test standard of reactor noise, the rules of emitted noise of the DAR are measured and analyzed at chosen switching frequency matches the sample resonant frequency and the methods of active vibration and noise reduction are put forward. Finally, the low acoustic noise emission of a prototype DAR is verified by measurement.

  20. Grain-boundary oxidation of used CANDU fuel exposed to dry air at 150 degrees C for a prolonged period

    International Nuclear Information System (INIS)

    Hocking, W.H.; Behnke, R.; Duclos, A.M.

    1995-01-01

    The grain-boundary chemistry of used CANDU fuel exposed to dry air at 150 degrees C for a prolonged period has been investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). High degrees of surface oxidation have been determined using the chemical-shift effects for the uranium photoelectron emission, but these must be largely restricted to thin films. The observed distribution of segregated fission products implies an absence of major fuel restructuring and SEM examinations revealed mainly subtle changes in the UO 2 grain structure. These findings are consistent with metallographic evidence of pervasive grain-boundary attack, despite only slight bulk alteration of the fluorite-lattice structure. (author)

  1. Techno-economic analysis of a roof-integrated solar air heating system for drying fruit and vegetables

    International Nuclear Information System (INIS)

    Sreekumar, A.

    2010-01-01

    The solar air heater was 46 m 2 and recorded a maximum temperature of 76.6 deg. C. The dryer was loaded with 200 kg of fresh pineapple slices 5 mm thick. The initial moisture content of 82% was reduced to the desired level (<10%) within 8 h. The performance of the dryer was analyzed in detail by three methods namely annualized cost, present worth of annual savings, and present worth of cumulative savings. The cost of drying 1 kg pineapple worked out to Rs. 11 which was roughly half of that of an electric dryer. The payback period worked out to 0.54 year, much less than the estimated life of the system (20 years).

  2. Comparison study on biosynthesis of silver nanoparticles using fresh and hot air oven dried IMPERATA CYLINDRICA leaf

    Science.gov (United States)

    Najmi Bonnia, Noor; Fairuzi, Afiza Ahmad; Akhir, Rabiatuladawiyah Md.; Yahya, Sabrina M.; Rani, Mohd Azri Ab; Ratim, Suzana; Rahman, Norafifah A.; Akil, Hazizan Md

    2018-01-01

    The perennial rhizomatous grass; Imperata cylindrica (I. cylindrica) has been reported rich in various phytochemicals. In present study, silver nanoparticles were synthesized from aqueous leaf extract of I. cylindrica at two different leaf conditions; fresh leaves and hot-air oven dried leaves. Biosynthesized silver nanoparticles were characterized by UV-visible spectroscopy, field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). Maximum absorption was recorded between 400 nm to 500 nm. FESEM analysis revealed that the silver nanoparticles predominantly form spherical shapes. The particles sizes were ranging from 22-37 nm. The elemental composition of the synthesized silver nanoparticles was confirmed by using energy dispersive X-ray spectroscopy (EDX) analysis. Fourier transform infrared spectroscopy (FTIR) confirmed the reducing and stabilizing actions came from biomolecules associated with I. cylindrica leaf extract. Thus in this investigation, an environmentally safe method to synthesized silver nanoparticles using local plant extract was successfully established.

  3. Reference natural radionuclide concentrations in Australian soils and derived terrestrial air kerma rate.

    Science.gov (United States)

    Kleinschmidt, R

    2017-06-01

    Sediment from drainage catchment outlets has been shown to be a useful means of sampling large land masses for soil composition. Naturally occurring radioactive material concentrations (uranium, thorium and potassium-40) in soil have been collated and converted to activity concentrations using data collected from the National Geochemistry Survey of Australia. Average terrestrial air kerma rate data are derived using the elemental concentration data, and is tabulated for Australia and states for use as baseline reference information. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  4. Effect of hot air drying on volatile compounds of Flammulina velutipes detected by HS-SPME-GC-MS and electronic nose.

    Science.gov (United States)

    Yang, Wenjian; Yu, Jie; Pei, Fei; Mariga, Alfred Mugambi; Ma, Ning; Fang, Yong; Hu, Qiuhui

    2016-04-01

    Volatile compounds are important factors that affect the flavor quality of Flammulina velutipes, but the changes occurring during hot air drying is still unclear. To clarify the dynamic changes of flavor components during hot air drying, comprehensive flavor characterization and volatile compounds of F. velutipes were evaluated using electronic nose technology and headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS), respectively. Results showed that volatile components in F. velutipes significantly changed during hot air drying according to the principal component analysis and radar fingerprint chart of electronic nose. Volatile compounds of fresh F. velutipes consisted mainly of ketones, aldehydes and alcohols, and 3-octanone was the dominant compound. Drying process could significantly decrease the relative content of ketones and promoted the generation of alcohols, acids, and esters, which became the main volatile compounds of dried F. velutipes. These may provide a theoretical basis for the formation mechanism of flavor substances in dried F. velutipes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Drivers of soil drying in the Czech Republic between 1961 and 2012

    Czech Academy of Sciences Publication Activity Database

    Trnka, Miroslav; Brázdil, Rudolf; Balek, J.; Semerádová, Daniela; Hlavinka, Petr; Možný, M.; Štěpánek, Petr; Dobrovolný, Petr; Zahradníček, Pavel; Dubrovský, Martin; Eitzinger, Josef; Fuchs, B.; Svoboda, M.; Hayes, M.; Žalud, Zdeněk

    2015-01-01

    Roč. 35, č. 9 (2015), s. 2664-2675 ISSN 0899-8418 R&D Projects: GA MŠk(CZ) LD13030; GA MŠk(CZ) EE2.3.20.0248; GA MŠk(CZ) EE2.3.20.0256; GA ČR GA13-04291S; GA MZe QJ1310123 Institutional support: RVO:67179843 ; RVO:68378289 Keywords : pan evaporation * soil moisture * reference evapotranspiration * drought climatology * water balance * observed climate change Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.609, year: 2015

  6. Soil water retention, air flow and pore structure characteristics after corn cob biochar application to a tropical sandy loam

    DEFF Research Database (Denmark)

    Amoakwah, Emmanuel; Frimpong, Kwame Agyei; Okae-Anti, D

    2017-01-01

    Soil structure is a key soil physical property that affects soil water balance, gas transport, plant growth and development, and ultimately plant yield. Biochar has received global recognition as a soil amendment with the potential to ameliorate the structure of degraded soils. We investigated how...... corn cob biochar contributed to changes in soil water retention, air flow by convection and diffusion, and derived soil structure indices in a tropical sandy loam. Intact soil cores were taken from a field experiment that had plots without biochar (CT), and plots each with 10 t ha− 1 (BC-10), 20 t ha...... to significant increase in soil water retention compared to the CT and BC-10 as a result of increased microporosity (pores biochar had minimal impact. No significant influence of biochar was observed for ka and Dp/D0 for the BC treatments compared to the CT despite...

  7. Radioecological investigations in the food-chain air-soil-vine-wine. Pt. 2

    International Nuclear Information System (INIS)

    Wagner, A.

    1989-10-01

    This Part 2 presents all of the results, including the harvest of 1986 and 1987; it thus describes the consequences of the Chernobyl accident. H-3, C-14, Sr-90 and Cs-137 were determined in soil, vine leaves, grapes and wine at different locations. In some of the samples Cs-134, K-40 and Ra-226 were also measured. Site-specific transfer factors were calculated for Sr-90 and for the Cs radionuclides. The mean content of Cs-137 before Chernobyl (after Chernogyl) was about 4 (9) Bq/kg dry matter in soil (top 30 cm), 0.07 (3) Bq/kg fresh matter in leaves, 0.02 (0.4) Bq/kg FM in grapes, and 0.008 (0.9) Bq/l in wine. As comapred to 1986 distinctly lower levels were found in leaves, grapes and wine from 1987. The content of Cs-134 was about half that of Cs-137 in 1986. Due to its shorter half-life Cs-134 had fallen below detection limit in many of the 1987 samples. Mean Sr-90 levels were 1-2 Bq/kg in soil and in leaves (dry matter and fresh matter, respectively), 19-56 mBq/kg in grapes, and 3-11 mBq/l in wine. Samples obtained in the fall of 1986 showed no increase of Sr-90 in soil and leaves, whereas a slight increase was found in grapes and wine as a consequence of Chernobyl. Site-specific influences such als soil parameters, climate, cultivation, vinification and differences between years had no pronounced effects on transfer factors. No influence of the nuclear power station Neckarwestheim has been found in any of the radionuclides. (orig./HP) [de

  8. Radioecological investigations in the food-chain air-soil-vine-wine. Pt. 2

    International Nuclear Information System (INIS)

    Wagner, A.

    1989-01-01

    This Part 2 presents all of the results, including the harvest of 1986 and 1987; it thus describes the consequences of the Chernobyl accident. H-3, C-14, Sr-90 and Cs-137 were determined in soil, vine leaves, grapes and wine at different locations. In some of the samples Cs-134, K-40 and Ra-226 were also measured. Site-specific transfer factors were calculated for Sr-90 and for the Cs radionuclides. The mean content of Cs-137 before Chernobyl (after Chernobyl) was about 4 (9) Bq/kg dry matter in soil (top 30 cm), 0.07 (3) Bq/kg fresh matter in leaves, 0.02 (0.4) Bq/kg FM in grapes, and 0.008 (0.9) Bq/l in wine. As compared to 1986 distinctly lower levels were found in leaves, grapes and wine from 1987. The content of Cs-134 was about half that of Cs-137 in 1986. Due to its shorter half-life Cs-134 had fallen below detection limit in many of the 1987 samples. Mean Sr-90 levels were 1-2 Bq/kg in soil and in leaves (dry matter and fresh matter, respectively), 19-56 mBq/kg in grapes, and 3-11 mBq/l in wine. Samples obtained in the fall of 1986 showed no increase of Sr-90 in soil and leaves, whereas a slight increase was found in grapes and wine as a consequence of Chernobyl. Site-specific influences such als soil parameters, climate, cultivation, vinification and differences between years had no pronounced effects on transfer factors. No influence of the nuclear power station Neckarwestheim has been found in any of the radionuclides. (orig./HP) [de

  9. Solar heating of air used for the drying at medium and large scale, of forestry, fishery, agriculture, cattle and industrial products

    International Nuclear Information System (INIS)

    Gutierrez, F.

    1991-01-01

    The drying process and/or preservation of grains is improved through the previous heating of air. In many cases it is enough to raise the temperature only a few degrees (from 10 to 15 Centigrade), in order to increase their capacity to absorb dampness. This can be done using very simple solar captors. A massive use of solar energy in the drying process of products, by means of hot air, can only be done with very expensive equipment. For this reason, it is recommended the use of lower thermic heaters, which will have a lower cost too. (Author)

  10. Variations of radon volume activities in soil and indoor air and their correlation

    International Nuclear Information System (INIS)

    Mojzes, A.

    1998-01-01

    Some manual measurements of volume activity of 222 Rn ai soil air and in indoor air of building together with parallel measurements of some meteorological parameters (temperature, humidity and pressure) of both atmospheric and indoor air were carried out. The measurements were performed in the building of Faculty and in its subsoil which consists of slope loams of the base of SW slopes of granitic Male Karpaty Mountains in the area of confluence of the Vidrica Creek with an arm of the Donau river. The monitoring measurements lasted form more than one and a half year, from January 1977 to August 1998, with the frequency of approximately once a week in each object. The soil air was taken from a permanently set up and sealed pipe from the depth of 0.8 m which was placed approximately 10 m from the building at the open air. All measurements of 222 Rn volume activities were performed with a portable fully automatic scintillation detector based on exchangeable Lucas cells. There were also performed the parallel measurements of some meteorological parameters (temperature, humidity and pressure) of air in each object. The geological basement of building is a source of indoor radon. The volume activities of soil 222 Rn range from about 2 kBq/m 3 to about 20 kBq/m 3 with the average of 9.26 kBq/m 3 and the standard deviation of 2.95 kBq/m 3 . The volume activities of indoor air in basement room were form 150 Bq/m 3 to 225 Bq/m 3 and on the third story they were from 125 Bq/m 3 to 175 Bq/m 3 (approximately). The results of monitoring measurements during 20 months period point out the intensity of interaction of geological substrate with building interior through the values of the volume activity of 222 Rn. Therefore a method of building foundation is one of the most important factors which determines the quantity of radon in indoor air. In the light of quality, the fluctuation of radon presence in the bottom part of the buildings is strongly determined by the variations of

  11. Evaluation of the soil-to-indoor air exposure pathway at petroleum contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    Kindzierski, W. B. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil Engineering

    1997-12-31

    Results of two approaches for evaluating human exposure to benzene inside a former gasoline station converted into a strip mall were discussed. Using passive air sampling, benzene levels inside the mall were evaluated. It was found that contrary to expectations the levels inside the mall were lower than the average levels in Canadian homes. The second approach, i.e. modeling of soil vapour entry, confirmed the findings of the passive air test by showing that incremental exposure conditions for mall workers was no worse than what they receive by inhalation in their own homes. 14 refs., 2 figs.

  12. Evaluation of the soil-to-indoor air exposure pathway at petroleum contaminated sites

    International Nuclear Information System (INIS)

    Kindzierski, W. B.

    1997-01-01

    Results of two approaches for evaluating human exposure to benzene inside a former gasoline station converted into a strip mall were discussed. Using passive air sampling, benzene levels inside the mall were evaluated. It was found that contrary to expectations the levels inside the mall were lower than the average levels in Canadian homes. The second approach, i.e. modeling of soil vapour entry, confirmed the findings of the passive air test by showing that incremental exposure conditions for mall workers was no worse than what they receive by inhalation in their own homes. 14 refs., 2 figs

  13. Soil drying and wind erosion as affected by different types of shelterbelts planted in the desert region of western Rajasthan, India

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, J.P.; Rao, G.G.S.N.; Gupta, G.N.; Rao, B.V.R.

    1983-03-01

    Studies on the effects of 8-year-old shelterbelt plantations indicate a general reduction in wind velocity, wind erosion and evaporative loss of moisture from fields protected with Prosopis juliflora, Cassia siamea and Acacia tortilis. Cassia siamea shelterbelts are the most effective in checking wind erosion and delaying drying of the soil. (Refs. 13).

  14. Variable pore connectivity model linking gas diffusivity and air-phase tortuosity to soil matric potential

    DEFF Research Database (Denmark)

    Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

    2012-01-01

    information on soil functional pore structure, e.g., pore network tortuosity and connectivity, can also be revealed from Dp/Do–ψ relations. Based on Dp/Do measurements in a wide range of soil types across geographically remote vadose zone profiles, this study analyzed pore connectivity for the development...... of a variable pore connectivity factor, X, as a function of soil matric potential, expressed as pF (=log |−ψ|), for pF values ranging from 1.0 to 3.5. The new model takes the form of X = X* (F/F*)A with F = 1 + pF−1, where X* is the pore network tortuosity at reference F (F*) and A is a model parameter......- and intraaggregate pore regions of aggregated soils. We further suggest that the new model with parameter values of X* = 1.7 and A = 0 may be used for upper limit Dp/Do predictions in risk assessments of, e.g., fluxes of toxic volatile organics from soil to indoor air at polluted soil sites....

  15. Pecan drying with silica gel

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, S.R.; Chhinnan, M.S.

    1983-07-01

    High moisture in-shell pecans were dried by keeping them in direct and indirect contact with silica gel to investigate their drying characteristics. In-shell pecans were also dried with ambient air from a controlled environment chamber and with air dehumidified by silica gel. Direct contact and dehumidified air drying seemed feasible approaches.

  16. Numerical analysis of temperature and flow effects in a dry, two-dimensional, porous-media reservoir used for compressed air energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, L.E.

    1979-10-01

    The purpose of the work is to define the hydrodynamic and thermodynamic response of a CAES dry porous media reservoir subjected to simulated air mass cycling. The knowledge gained will provide, or will assist in providing, design guidelines for the efficient and stable operation of the air storage reservoir. The analysis and results obtained by two-dimensional modeling of dry reservoirs are presented. While the fluid/thermal response of the underground system is dependent on many parameters, the two-dimensional model was applied only to those parameters that entered the analysis by virtue of inclusion of the vertical dimension. In particular, the parameters or responses that were quantified or characterized include wellbore heat transfer, heat losses to the vertical boundaries of the porous zone, gravitationally induced flows, producing length of the wellbore, and the effects of nonuniform permeability. The analysis of the wellbore heat transfer included consideration of insulation, preheating (bubble development with heated air), and air mass flow rate.

  17. AirMOSS P-Band Radar Retrieval of Subcanopy Soil Moisture Profile

    Science.gov (United States)

    Tabatabaeenejad, A.; Burgin, M. S.; Duan, X.; Moghaddam, M.

    2013-12-01

    Knowledge of soil moisture, as a key variable of the Earth system, plays an important role in our under-standing of the global water, energy, and carbon cycles. The importance of such knowledge has led NASA to fund missions such as Soil Moisture Active and Passive (SMAP) and Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS). The AirMOSS mission seeks to improve the estimates of the North American Net Ecosystem Exchange (NEE) by providing high-resolution observations of the root zone soil moisture (RZSM) over regions representative of the major North American biomes. AirMOSS flies a P-band SAR to penetrate vegetation and into the root zone to provide estimates of RZSM. The flights cover areas containing flux tower sites in regions from the boreal forests in Saskatchewan, Canada, to the tropical forests in La Selva, Costa Rica. The radar snapshots are used to generate estimates of RZSM via inversion of a scattering model of vegetation overlying soils with variable moisture profiles. These retrievals will be used to generate a time record of RZSM, which will be integrated with an ecosystem demography model in order to estimate the respiration and photosynthesis carbon fluxes. The aim of this work is the retrieval of the moisture profile over AirMOSS sites using the collected P-band radar data. We have integrated layered-soil scattering models into a forest scattering model; for the backscattering from ground and for the trunk-ground double-bounce mechanism, we have used a layered small perturbation method and a coherent scattering model of layered soil, respectively. To estimate the soil moisture profile, we represent it as a second-order polynomial in the form of az2 + bz + c, where z is the depth and a, b, and c are the coefficients to be retrieved from radar measurements. When retrieved, these coefficients give us the soil moisture up to a prescribed depth of validity. To estimate the unknown coefficients of the polynomial, we use simulated

  18. Theoretical and Experimental Evaluation of the Temperature Distribution in a Dry Type Air Core Smoothing Reactor of HVDC Station

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2017-05-01

    Full Text Available The outdoor ultra-high voltage (UHV dry-type air-core smoothing reactors (DASR of High Voltage Direct Current systems are equipped with a rain cover and an acoustic enclosure. To study the convective heat transfer between the DASR and the surrounding air, this paper presents a coupled model of the temperature and fluid field based on the structural features and cooling manner. The resistive losses of encapsulations calculated by finite element method (FEM were used as heat sources in the thermal analysis. The steady fluid and thermal field of the 3-D reactor model were solved by the finite volume method (FVM, and the temperature distribution characteristics of the reactor were obtained. Subsequently, the axial and radial temperature distributions of encapsulation were investigated separately. Finally, an optical fiber temperature measurement scheme was used for an UHV DASR under natural convection conditions. Comparative analysis showed that the simulation results are in good agreement with the experimental data, which verifies the rationality and accuracy of the numerical calculation. These results can serve as a reference for the optimal design and maintenance of UHV DASRs.

  19. Environmental monitoring (water, soil, air, food) and some methodological aspects of radioactive decontamination

    International Nuclear Information System (INIS)

    Balanel, Vasile; Boldescu, Victoria; Mesina, Victor

    2013-01-01

    This paper presents research results of radiological samples taken from various media (water, soil, air and some food). The study showed that concentrations of radionuclides Cs 137 and Sr 90 did not exceed the maximum permissible. A high level of radionuclides but within the norm occurred in some imported food. The research describes methodology used in radioactive decontamination in practice of the modern world. (authors)

  20. Dragonfly (insecta: odonata) diversity in two use of soils in a tropical dry forest

    International Nuclear Information System (INIS)

    Altamiranda S, Mariano

    2009-01-01

    Dragonfly diversity was estimated in the Agricultural Center Cotove (Santafe de Antioquia-Colombia). Active capture using an entomological net was used. Each transect was located perpendicular to the water body, for a length of approximately 200 m and a lateral extension of 8 m. Twenty Odonata species were registered, from 5 families and 15 genus. Libellulidae showed the biggest abundance and richness, with 65 specimens that represent 53.7% of the total abundance, and 12 species that represent 60% of the registered community. The diversity was high in the forest in reference at crop; however, the low abundances register highlight the need for greater sampling effort in cultivating, for a better estimate of ? diversity; the diversity was of 12 species and the complementary index was of 0.6, it indicates that the Odonata's fauna is characteristic and distinctive for each use of soil.

  1. The behaviour of iodine in the compartments soil, plant and air

    International Nuclear Information System (INIS)

    Pel, E.

    1993-02-01

    Within the framework of this study, several investigations were carried out into the behaviour of iodine in the soil-plant-air system. Particular attention was given to the mechanisms determining iodine transfer from soil to plant. Measurements of iodine contents in the soil, plants and individual parts of plants were as important an aim of this study as was the identification of factors possibly contributing to an abundant iodine uptake into plants. In view of iodine's role as an element essential to the health of both humans and animals, widely cultured forage crops and useful plants were investigated in this connection. As the relevant literature quotes unusually high contents of the substance for a number of foodstuffs based on plants, these were included in the studies for iodine contents. (orig.) [de

  2. Effect of air turbulence on gas transport in soil; comparison of approaches

    Science.gov (United States)

    Pourbakhtiar, Alireza; Papadikis, Konstantinos; Poulsen, Tjalfe; Bridge, Jonathan; Wilkinson, Stephen

    2017-04-01

    Greenhouse gases are playing the key role in global warming. Soil is a source of greenhouse gases such as methane (CH4). Radon (Rn) which is a radioactive gas can emit form subsurface into the atmosphere and leads to health concerns in urban areas. Temperature, humidity, air pressure and vegetation of soil can affect gas emissions inside soil (Oertel et al., 2016). It's shown in many cases that wind induced fluctuations is an important factor in transport of gas through soil and other porous media. An example is: landfill gas emissions (Poulsen et al., 2001). We applied an experimental equipment for measuring controlled air turbulence on gas transport in soil in relation to the depth of sample. Two approaches for measurement of effect of wind turbulence on gas transport were applied and compared. Experiments were carried out with diffusion of CO2 and air as tracer gases with average vertical wind speeds of 0 to 0.83 m s-1. In approach A, Six different sample thicknesses from 5 to 30 cm were selected and total of 4 different wind conditions with different speed and fluctuations were applied. In approach B, a sample with constant depth was used. Five oxygen sensors were places inside sample at different depths. Total of 111 experiments were carried out. Gas transport is described by advection-dispersion equation. Gas transport is quantified as a dispersion coefficient. Oxygen breakthrough curves as a function of distance to the surface of the sample exposed to wind were derived numerically with an explicit forward time, central space finite-difference based model to evaluate gas transport. We showed that wind turbulence-induced fluctuations is an important factor in gas transport that can increase gas transport with average of 45 times more than molecular diffusion under zero wind condition. Comparison of two strategies for experiments, indicated that, constant deep samples (Approach B) are more reliable for measurement of gas transport under influence of wind

  3. Effect of dry land transformation and quality of water use for crop irrigation on the soil bacterial community in the Mezquital Valley, Mexico

    Science.gov (United States)

    Lüneberg, Kathia; Schneider, Dominik; Daniel, Rolf; Siebe, Christina

    2017-04-01

    Soil bacteria are important determinants of soil fertility and ecosystem services as they participate in all biogeochemical cycles. Until now the comprehension of compositional and functional response that bacterial communities have to land use change and management, specifically in dry land its limited. Dry lands cover 40% of the world's land surface and its crop production supports one third of the global population. In this regions soil moisture is limited constraining farming to the rainy season or oblige to irrigate, as fresh water resources become scarce, to maintain productivity, treated or untreated wastewater for field irrigation is used. In this study the transformation of semiarid shrubland to agriculture under different land systems regarding quantity and quality of water use for crop irrigation on bacterial communities was investigated. The land systems included maize rain-fed plantations and irrigation systems with freshwater, untreated wastewater stored in a dam and untreated wastewater during dry and rainy season. Bacterial community structure and function was heavily affected by land use system and soil properties, whereas seasonality had a slighter effect. A soil moisture, nutrient and contaminant-content increasing gradient among the land use systems, going from rain fed plantation over fresh water, dam wastewater to untreated wastewater irrigated plantations was detected, this gradient diminished the abundance of Actinobacteria and Cyanobacteria, but enhanced the one from Bacteroidetes and Proteobacteria. Discernible clustering of the dry land soil communities coincides with the moisture, nutrient and contaminant gradient, being shrubland soil communities closer to the rain-fed's system and farer to the one from untreated wastewater irrigated soil. Soil moisture together with sodium content and pH were the strongest drivers of the community structure. Seasonality promoted shifts in the composition of soil bacteria under irrigation with

  4. The application of in situ air sparging as an innovative soils and ground water remediation technology

    International Nuclear Information System (INIS)

    Marley, M.C.; Hazebrouck, D.J.; Walsh, M.T.

    1992-01-01

    Vapor extraction (soil venting) has been demonstrated to be a successful and cost-effective remediation technology for removing VOCs from the vadose (unsaturated) zone. However, in many cases, seasonal water table fluctuations, drawdown associated with pump-and-treat remediation techniques, and spills involving dense, non-aqueous phase liquids (DNAPLS) create contaminated soil below the water table. Vapor extraction alone is not considered to be an optimal remediation technology to address this type of contamination. An innovative approach to saturated zone remediation is the use of sparging (injection) wells to inject a hydrocarbon-free gaseous medium (typically air) into the saturated zone below the areas of contamination. The contaminants dissolved in the ground water and sorbed onto soil particles partition into the advective air phase, effectively simulating an in situ air-stripping system. The stripped contaminants are transported in the gas phase to the vadose zone, within the radius of influence of a vapor extraction and vapor treatment system. In situ air sparging is a complex multifluid phase process, which has been applied successfully in Europe since the mid-1980s. To date, site-specific pilot tests have been used to design air-sparging systems. Research is currently underway to develop better engineering design methodologies for the process. Major design parameters to be considered include contaminant type, gas injection pressures and flow rates, site geology, bubble size, injection interval (areal and vertical) and the equipment specifications. Correct design and operation of this technology has been demonstrated to achieve ground water cleanup of VOC contamination to low part-per-billion levels

  5. Prognostication of the radioactive contamination with iodine 131, strontium 90 and cesium 137 of the air and soil after commissioning the ''Kozloduj'' nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Khristova, M; Paskalev, Z [Nauchno-Izsledovatelski Inst. po Radiologiya i Radiatsionna Khigiena, Sofia (Bulgaria)

    1975-01-01

    The content of iodine 131, strontium 90 and cesium 137 in the air (curie/l) and soil (curie/m/sup 2/ sec) in the area of the Kozloduj atomic power station (at a distance from 3 to 75 km from the chimney-stack of the power station) was determined. The concentrations of these radionuclides are determined under different meteorologic conditions: air temperature from -20/sup 0/C to +20/sup 0/C and a wind speed from 2 m/sec to 30 m/sec. The data show that at -20/sup 0/C radionuclide concentrations in the air decrease with increasing distance from the chimney-stack, regardless of the speed of the wind. At +20/sup 0/C radionuclide concentrations in the air increase with the distance from the chimney-stack, peak at a definite distance and then decrease. At 2 m/sec and speed this maximum is at a distance of 50 km from station. As the speed of the air increases, the peak moves nearer and remains about 30 km from the power station. Results on ground surface concentrations show that a trend is observed toward persistent decrease with distance from the power station. In rainy weather they are almost four times higher than in dry weather. The radionuclide concentrations on the ground surface will be comparable to their global deposits.

  6. Assessment of heavy metal pollution in soils along major roadside ...

    African Journals Online (AJOL)

    EJIRO

    African Journal of Environmental Science and Technology Vol. 5(3), pp ... of Agricultural Engineering and Land Planning, Botswana College of Agriculture, Private Bag 0027, .... Collected soil samples were air-dried to constant weight and then ...

  7. Evaluation of short-term tracer fluctuations in groundwater and soil air in a two year study

    Science.gov (United States)

    Jenner, Florian; Mayer, Simon; Aeschbach, Werner; Weissbach, Therese

    2016-04-01

    The application of gas tracers like noble gases (NGs), SF6 or CFCs in groundwater studies such as paleo temperature determination requires a detailed understanding of the dynamics of reactive and inert gases in the soil air with which the infiltrating water equilibrates. Due to microbial gas consumption and production, NG partial pressures in soil air can deviate from atmospheric air, an effect that could bias noble gas temperatures estimates if not taken into account. So far, such an impact on NG contents in groundwater has not been directly demonstrated. We provide the first long-term study of the above mentioned gas tracers and physical parameters in both the saturated and unsaturated soil zone, sampled continuously for more than two years near Mannheim (Germany). NG partial pressures in soil air correlate with soil moisture and the sum value of O2+CO2, with a maximal significant enhancement of 3-6% with respect to atmospheric air during summer time. Observed seasonal fluctuations result in a mass dependent fractionation of NGs in soil air. Concentrations of SF6 and CFCs in soil air are determined by corresponding fluctuations in local atmospheric air, caused by industrial emissions. Arising concentration peaks are damped with increasing soil depth. Shallow groundwater shows short-term NG fluctuations which are smoothed within a few meters below the water table. A correlation between NG contents of soil air and of groundwater is observable during strong recharge events. However, there is no evidence for a permanent influence of seasonal variations of soil air composition on shallow groundwater. Fluctuating NG contents in shallow groundwater are rather determined by variations of soil temperature and water table level. Our data gives evidence for a further temperature driven equilibration of groundwater with entrapped air bubbles within the topmost saturated zone, which permanently occurs even some years after recharge. Local subsurface temperature fluctuations

  8. Electrical characterization of microdischarges produced by dielectric barrier discharge in dry air at atmospheric pressure

    International Nuclear Information System (INIS)

    Jidenko, N; Petit, M; Borra, J P

    2006-01-01

    This work addresses the case of millimetre sized plane-to-plane dielectric barrier discharge with sinusoidal voltage between 1 and 60 kHz for different configurations in air at atmospheric pressure. The first aim of this work is to achieve a representative statistical analysis of the electrical characteristics of the microdischarges. The numerical data treatment presented here enables us to determine the maximum current, the duration, the amount of charge and the triggering voltage for each current pulse. Both the average values as well as the deviations are checked. The relative influence of the operating parameters (voltage, gas flow rate, gap width, frequency) on the local surface polarization, electron attachment and temperature affecting microdischarge characteristics has been depicted in different arrangements. A special attention is paid to the influence of dielectric walls inside the discharge gap, perpendicular to the electrodes. Besides, this study allows the identification of the operating conditions for which all the microdischarges can be considered identical to study the local physical and chemical processes around each microdischarge

  9. Electrical characterization of microdischarges produced by dielectric barrier discharge in dry air at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Jidenko, N [Laboratoire de Physique des Gaz et des Plasmas (CNRS-Universite Paris XI), Equipe Decharges Electriques et Environnement, Supelec, 91190 Gif sur Yvette (France); Petit, M [Service Electrotechnique et Electronique Industrielle, SUPELEC Plateau de Moulon, 91192 Gif sur Yvette Cedex (France); Borra, J P [Laboratoire de Physique des Gaz et des Plasmas (CNRS-Universite Paris XI), Equipe Decharges Electriques et Environnement, Supelec, 91190 Gif sur Yvette (France)

    2006-01-21

    This work addresses the case of millimetre sized plane-to-plane dielectric barrier discharge with sinusoidal voltage between 1 and 60 kHz for different configurations in air at atmospheric pressure. The first aim of this work is to achieve a representative statistical analysis of the electrical characteristics of the microdischarges. The numerical data treatment presented here enables us to determine the maximum current, the duration, the amount of charge and the triggering voltage for each current pulse. Both the average values as well as the deviations are checked. The relative influence of the operating parameters (voltage, gas flow rate, gap width, frequency) on the local surface polarization, electron attachment and temperature affecting microdischarge characteristics has been depicted in different arrangements. A special attention is paid to the influence of dielectric walls inside the discharge gap, perpendicular to the electrodes. Besides, this study allows the identification of the operating conditions for which all the microdischarges can be considered identical to study the local physical and chemical processes around each microdischarge.

  10. Does the increased air humidity affect soil respiration and carbon stocks?

    Science.gov (United States)

    Kukumägi, Mai; Celi, Luisella; Said-Pullicino, Daniel; Kupper, Priit; Sõber, Jaak; Lõhmus, Krista; Kutti, Sander; Ostonen, Ivika

    2013-04-01

    Climate manipulation experiments at ecosystem-scale enable us to simulate, investigate and predict changes in carbon balance of forest ecosystems. Considering the predicted increase in air humidity and precipitation for northern latitudes, this work aimed at investigating the effect of increased air humidity on soil respiration, distribution of soil organic matter (SOM) among pools having different turnover times, and microbial, fine root and rhizome biomass. The study was carried out in silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.) stands in a Free Air Humidity Manipulation (FAHM) experimental facility containing three humidified (H; on average 7% above current ambient levels since 2008) and three control (C) plots. Soil respiration rates were measured monthly during the growing season using a closed dynamic chamber method. Density fractionation was adopted to separate SOM into two light fractions (free and aggregate-occluded particulate organic matter, fPOM and oPOM respectively), and one heavy fraction (mineral-associated organic matter, MOM). The fine root and rhizome biomass and microbial data are presented for silver birch stands only. In 2011, after 4 growing seasons of humidity manipulation soil organic carbon contents were significantly higher in C plots than H plot (13.5 and 12.5 g C kg-1, respectively), while soil respiration tended to be higher in the latter. Microbial biomass and basal respiration were 13 and 14% higher in H plots than in the C plots, respectively. Twice more fine roots of trees were estimated in H plots, while the total fine root and rhizome biomass (tree + understory) was similar in C and H plots. Fine root turnover was higher for both silver birch and understory roots in H plots. Labile SOM light fractions (fPOM and oPOM) were significantly smaller in H plots with respect to C plots (silver birch and hybrid aspen stands together), whereas no differences were observed in the

  11. X-ray CT-Derived Soil Characteristics Explain Varying Air, Water, and Solute Transport Properties across a Loamy Field

    DEFF Research Database (Denmark)

    Paradelo Pérez, Marcos; Katuwal, Sheela; Møldrup, Per

    2016-01-01

    -derived parameters by using a best subsets regression analysis. The regression coefficients improved using CTmatrix, limiting macroporosity, and genus density, while the best model for t0.05 used CTmatrix only. The scanning resolution and the time for soil structure development after mechanical activities could......The characterization of soil pore space geometry is important for explaining fluxes of air, water, and solutes through soil and understanding soil hydrogeochemical functions. X-ray computed tomography (CT) can be applied for this characterization, and in this study CT-derived parameters were used...... to explain water, air, and solute transport through soil. Forty-five soil columns (20 by 20 cm) were collected from an agricultural field in Estrup, Denmark, and subsequently scanned using a medical CT scanner. Nonreactive tracer leaching experiments were performed in the laboratory along with measurements...

  12. Effect of process parameters on energy performance of spray drying with exhaust air heat recovery for production of high value particles

    International Nuclear Information System (INIS)

    Julklang, Wittaya; Golman, Boris

    2015-01-01

    Highlights: • We study heat recovery from spray dryer using air-to-air heat exchanger. • We examine dryer energy performance using advanced mathematical model. • We use the response surface methodology to study the effect of process parameters. • Energy efficiency up to 43.3% is obtained at high flow rate of dilute slurry. • Energy saving up to 52.4% is obtained at high drying air temperature. - Abstract: Spray drying process has been widely used in various industries for many decades for production of numerous materials. This paper explores the energy performance of an industrial scale spray dryer equipped with an exhaust air heat recovery system for production of high value particles. Energy efficiency and energy saving were calculated using a comprehensive mathematical model of spray drying. The response surface methodology (RSM) was utilized to study the effect of process parameters on energy performance using a space-filling design. The meta model equations were formulated employing the well-fitted response surface equations with adjusted R 2 larger than 0.995. The energy efficiency as high as 43.3% was obtained at high flow rate of dilute slurry, while the highest energy saving of 52.4% was found by combination of positive effect of drying air temperature and negative effect of slurry mass flow rate. The utilization of efficient air-to-air heat exchanger leads to an increase in energy efficiency and energy savings. The detailed temperature and vapor concentration profiles obtained with the model are also valuable in determining final product quality when spray dryer is operated at energy efficient conditions

  13. Soil erosion and causative factors at Vandenberg Air Force Base, California

    Science.gov (United States)

    Butterworth, Joel B.

    1988-01-01

    Areas of significant soil erosion and unvegetated road cuts were identified and mapped for Vandenberg Air Force Base. One hundred forty-two eroded areas (most greater than 1.2 ha) and 51 road cuts were identified from recent color infrared aerial photography and ground truthed to determine the severity and causes of erosion. Comparison of the present eroded condition of soils (as shown in the 1986 photography) with that in historical aerial photography indicates that most erosion on the base took place prior to 1928. However, at several sites accelerated rates of erosion and sedimentation may be occurring as soils and parent materials are eroded vertically. The most conspicuous erosion is in the northern part of the base, where severe gully, sheet, and mass movement erosion have occurred in soils and in various sedimentary rocks. Past cultivation practices, compounded by highly erodible soils prone to subsurface piping, are probably the main causes. Improper range management practices following cultivation may have also increased runoff and erosion. Aerial photography from 1986 shows that no appreciable headward erosion or gully sidewall collapse have occurred in this area since 1928.

  14. Measurement of natural radioactivity contents in air and soil from Western, Haryana, India

    International Nuclear Information System (INIS)

    Mann, Nisha; Sushil Kumar; Amit Kumar; Garg, Ajay; Chauhan, R.P.

    2015-01-01

    Measurement of indoor radon and thoron is of importance because the radiation dose to human population due to inhalation of radon and its daughters contributes more than 50% of the total dose from natural sources. Thus it is important to study their levels in the dwellings and workplace. The gases are exhaled by soil and building materials due to presence of radium and thorium. One of the important index to find out the contribution of soil and building materials towards indoor radon is radon exhalation rates, which can be used for estimation of indoor radon levels. In present work the indoor radon and thoron levels from the air and radon exhalation rates from soil samples collected from the some districts (Sirsa, Hisar and Fatehabad) of North Haryana are reported. The indoor radon levels were measured by pin hole based radon thoron dosimeter and LR-115 solid state nuclear track detector while the radon exhalation rates from soil samples by well known canister techniques. The results show that indoor radon and thoron levels varied from 11 to 112 Bq/m 3 and 44 to 204 Bq/m 3 from the study area and within the ICRP safety limits. The radon mass exhalation rates from the soil sample varied from 12 to 37 mBq/kg/h. There exists a poor correlation between indoor radon and exhalation rates. An effort is made to explain the observed correlation. The results of the measurement are also compared with various National and International studies. (author)

  15. The correlations between Radon in soil gas and its exhalation and concentration in air in the southern part of Syria

    International Nuclear Information System (INIS)

    Shweikani, R.; Hushari, M.

    2005-01-01

    The aim of this work is to measure the concentration of the radon ( 222 Rn) in soil air, 222 Rn exhalation from soil and 222 Rn in outdoor air which may have great influence on 222 Rn levels in houses. 222 Ra activity concentrations were also determined in soil samples. The studied areas are located in southern part of Syria. The common bed rock of this area is black and massive granite which are poor in uranium content [Jubeli Y.M., 1990. Uranium exploration in Syria. Internal Technical Report, vol. 1 (in English), vol. 2 (in Arabic), SAEC, Damascus; Technoexport (USSR), 1966. In: Ponikarov (Ed.), The Geological Map of Syria Scale: 1:200.000, Ministry of Industry, Damascus, Syria]. Results showed that the maximum measurement in all areas was 32500Bqm -3 in soil air with an exhalation rate of 9Bqm -2 s -1 in Darra region and 66.43Bqm -3 of radon in open air, with 77Bqkg -1 of radium content in soil (Damascus suburb). In addition, correlations between Rn in soil and exhalation of Radon from soil and radon in houses were found in some areas (Sweda and Darra), while, no correlations were found in other studied areas. Moreover, no correlation between radon in houses and radon measurements in soil and in outdoors were found. This was attributed to the methodology used and the influence of building design and inhabitants behavior

  16. The effects of rice canopy on the air-soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers.

    Science.gov (United States)

    Wang, Yan; Wang, Shaorui; Luo, Chunling; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

    2015-05-01

    The rice canopy in paddy fields can influence the air-soil exchange of organic chemicals. We used paired passive air samplers to assess the exchange of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in a paddy field, South China. Levels of OCPs and light PAHs were generally higher under the canopy than above it. We found that the rice canopy can physically obstruct the evaporation of most OCPs and light PAHs, and can also act as a barrier to the gaseous deposition of p,p'-DDT and heavy PAHs. Paddy fields can behave as a secondary source of OCPs and light PAHs. The homolog patterns of these two types of chemical varied slightly between the air below and above the rice canopy, implying contributions of different sources. Paired passive air samplers can be used effectively to assess the in situ air-soil exchange of PAHs and OCPs in subtropical paddy fields. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. A passive air sampler for characterizing the vertical concentration profile of gaseous phase polycyclic aromatic hydrocarbons in near soil surface air.

    Science.gov (United States)

    Zhang, Yuzhong; Deng, Shuxing; Liu, Yanan; Shen, Guofeng; Li, Xiqing; Cao, Jun; Wang, Xilong; Reid, Brian; Tao, Shu

    2011-03-01

    Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAH(LMW4)) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAH(LMW4) within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Effects of land use change and seasonality of precipitation on soil nitrogen in a dry tropical forest area in the Western Llanos of Venezuela.

    Science.gov (United States)

    González-Pedraza, Ana Francisca; Dezzeo, Nelda

    2014-01-01

    We evaluated changes of different soil nitrogen forms (total N, available ammonium and nitrate, total N in microbial biomass, and soil N mineralization) after conversion of semideciduous dry tropical forest in 5- and 18-year-old pastures (YP and OP, resp.) in the western Llanos of Venezuela. This evaluation was made at early rainy season, at end rainy season, and during dry season. With few exceptions, no significant differences were detected in the total N in the three study sites. Compared to forest soils, YP showed ammonium losses from 4.2 to 62.9% and nitrate losses from 20.0 to 77.8%, depending on the season of the year. In OP, the ammonium content increased from 50.0 to 69.0% at the end of the rainy season and decreased during the dry season between 25.0 and 55.5%, whereas the nitrate content increased significantly at early rainy season. The net mineralization and the potentially mineralizable N were significantly higher (P forest and YP, which would indicate a better quality of the substrate in OP for mineralization. The mineralization rate constant was higher in YP than in forest and OP. This could be associated with a reduced capacity of these soils to preserve the available nitrogen.

  19. Clay Dispersibility and Soil Friability-Testing the Soil Clay-to-Carbon Saturation Concept

    DEFF Research Database (Denmark)

    Schjønning, Per; de Jonge, Lis Wollesen; Munkholm, Lars Juhl

    2012-01-01

    Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC...... as a predictor of clay dispersibility and soil friability. Soil was sampled 3 yr in a field varying in clay content (∼100 to ∼220 g kg−1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1- to 2-mm sized aggregates either air......-dried or rewetted to −100 hPa matric potential. Tensile strength of 1- to 2-, 2- to 4-, 4- to 8-, and 8- to 16-mm air-dried aggregates was calculated from their compressive strength, and soil friability estimated from the strength–volume relation. Crop rotation characteristics gave only minor effects on clay...

  20. Effects of hot air and freeze drying methods on antioxidant activity, colour and some nutritional characteristics of strawberry tree (Arbutus unedo L) fruit.

    Science.gov (United States)

    Orak, H H; Aktas, T; Yagar, H; İsbilir, S Selen; Ekinci, N; Sahin, F Hasturk

    2012-08-01

    Antioxidant activity, colour and some nutritional properties of hot air and freeze-dried strawberry tree (Arbutus unedo L.) fruits were investigated. Additionally, the effects of two pre-treatments, namely ethyl oleate and water blanching, were compared in terms of drying characteristics. For determination of antioxidant activities in ethanol extracts, two different analytical methods were used: 1,1-diphenyl-2-picrylhydrazyl scavenging activity and β-carotene bleaching activity. As a result, the ethyl oleate pre-treatment shortened the drying time by hot air method and gave a higher 1,1-diphenyl-2-picrylhydrazyl scavenging activity (82.16 ± 0.34%), total phenolic content (7.62 ± 1.09 µg GAE/g extract), ascorbic acid content (236.93 ± 20.14 mg/100 g), besides hydromethylfurfural was not observed. Freeze-dried fruits exhibited higher ascorbic acid content (368.63 ± 17.16 mg/100 g) than those fresh fruits (231.33 ± 19.51 mg/100 g) and nearly 1,1-diphenyl-2-picrylhydrazyl activity (93.52 ± 0.41 %) to fresh fruits (94.03 ± 1.18%). Colour characteristics, sugar content and mineral contents of fruits were significantly affected by pre-treatments and drying methods (p drying of strawberry tree fruits should bring a valuable and attractive foodstuff to food industry due to the rich nutritional components, antioxidant activity and colour. Another conclusion from this study is that the freeze-drying is the best drying method to keep the nutritional value, antioxidant activity and sensory properties of fruits.

  1. Linking air and water transport in intact soils to macro-porosity by combining laboratory measurements and X-ray Computed Tomography

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Norgaard, Trine; Møldrup, Per

    -porosity (R2 = 0.80 for air permeability: R2= 0.61 for 5% arrival time) and macro-porosity of the restricting layer (R2=0.83 for air permeability: R2= 0.71 for 5% arrival time) over air-filled porosity and all the correlations were positive. The high positive correlation these air and water transport...... functions with macro-porosity stressed the importance of continuity and tortuosity of pores in air, water and solute flow and transport through the soils. Negative correlations of air permeability, 5% arrival time of tracer and macro-porosity were obtained with bulk density whereas with other soil physical......With an objective to link the hydraulic properties of soil with the soil structural properties, air permeability and 5% arrival time of a conservative tracer was measured for large undisturbed soil columns from the same agricultural field. The same soil columns were scanned with a medical scanner...

  2. Assessing soil hydrological variability at the cm- to dm-scale using air permeameter measurements

    Science.gov (United States)

    Beerten, K.; Vandersmissen, N.; Rogiers, B.; Mallants, D.

    2012-04-01

    Soils and surficial sediments are crucial elements in the hydrological cycle since they are the medium through which infiltrating precipitation percolates to the aquifer. At the same time, soil horizons and shallow stratigraphy may act as hydraulic barriers that can promote runoff or interflow and hamper deep infiltration. For most catchments little is known about the small-scale horizontal and vertical variability of soil hydrological properties. Such information is however required to calculate detailed soil water flow paths and estimate small scale spatial variability in recharge and run-off. We present the results from field air permeameter measurements to assess the small-scale variability of saturated hydraulic conductivity in heterogeneous 2-D soil profiles. To this end, several outcrops in the unsaturated zone (sandy soils with podzolisation) of an interfluve in the Kleine Nete river catchment (Campine area, Northern Belgium) were investigated using a hand-held permeameter. Measurements were done each 10 cm on ~ 2 x 1 m or ~ 2 x 0.5 m grids. The initial results of the measurements (air permeability Kair; millidarcy) are recalculated to saturated hydraulic conductivity (Ks; m/s) using specific transfer functions (Loll et al., 1999; Iversen et al., 2003). Validation of the results is done with independent lab-based constant head Ks measurements. The results show that field based Ks values generally range between 10-3 m/s and 10-7 m/s within one profile, but extremely high values (up to 10-1 m/s) have been measured as well. The lowest values are found in the organic- and silt-rich Bh horizon of podzol soils observed within the profiles (~ 10-6-10-7m/s), while the highest values are observed in overlying dune sands less than 40 cm deep (up to 10-3 m/s with outliers to 10-1 m/s). Comparison of field and laboratory based Ks data reveals there is fair agreement between both methods, apart from several outliers. Scatter plots indicate that almost all points

  3. Radiative warming of the air observed near a bare-soil surface on calm clear nights

    International Nuclear Information System (INIS)

    Sang, N.; Kobayahsi, T.

    1999-01-01

    The radiative flux in the lowest three meters above a bare-soil surface was directly measured on calm nights with little cloud cover. Although divergence of upward radiative flux occurred above 1m, convergence was often observed between 0.2m and 1m all through the night. Almost the same results were obtained for the net flux except that the transitional height between divergence and convergence was some tens of centimeters, which means that radiative warming occurred just above the bare-soil surface during the night. This phenomenon can be explained by postulating that cold air is produced by conduction at the surface of small heat-insulated projections (HIPs) such as soil grains on the ground surface, while the ground releases the heat stored during the day by radiation through the pores between HIPs and warms the air immediately above the surface at night. This “HIP hypothesis” can also account for the so-called “raised minimum (RM)” phenomenon. (author)

  4. Mercury pollution of effluent, air, and soil near a battery factory in Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Semu, E.; Singh, B.R.; Selmer-Olsen, A.R.

    1986-01-01

    Effluent, air, and soil samples near a battery factory in Dar es Salaam, Tanzania, where HgCl/sub 2/ is used to prevent mold growth, were collected to explore the potential for pollution of the environment from industrial discharge of Hg. Flameless atomic absorption spectrophotometry was used for Hg determinations. The concentration of Hg in the effluent ranged from <0.2 to 5.2 mg L/sup -1/ and the Hg concentration varied greatly within and among sampling days, showing different peaks. Air contained a mean of 4.0 ..mu..g m /sup -3/ with little variation within and between sampling days. Soils near the factory contained high Hg levels, from 6.7 to 472 mg kg/sup -1/ in the immediate vicinity, the highest level being associated with disposal of solid waste (defective batteries). Downwind the concentration of Hg decreased with increasing distance from the factory resulting in a soil concentration of 1.0 mg Hg kg/sup -1/ about 2 km away. Upwind the Hg concentration decreased drastically within a distance of 100 to 200 m.

  5. Response of Surface Soil Hydrology to the Micro-Pattern of Bio-Crust in a Dry-Land Loess Environment, China.

    Science.gov (United States)

    Wei, Wei; Yu, Yun; Chen, Liding

    2015-01-01

    The specific bio-species and their spatial patterns play crucial roles in regulating eco-hydrologic process, which is significant for large-scale habitat promotion and vegetation restoration in many dry-land ecosystems. Such effects, however, are not yet fully studied. In this study, 12 micro-plots, each with size of 0.5 m in depth and 1 m in length, were constructed on a gentle grassy hill-slope with a mean gradient of 8° in a semiarid loess hilly area of China. Two major bio-crusts, including mosses and lichens, had been cultivated for two years prior to the field simulation experiments, while physical crusts and non-crusted bare soils were used for comparison. By using rainfall simulation method, four designed micro-patterns (i.e., upper bio-crust and lower bare soil, scattered bio-crust, upper bare soil and lower bio-crust, fully-covered bio-crust) to the soil hydrological response were analyzed. We found that soil surface bio-crusts were more efficient in improving soil structure, water holding capacity and runoff retention particularly at surface 10 cm layers, compared with physical soil crusts and non-crusted bare soils. We re-confirmed that mosses functioned better than lichens, partly due to their higher successional stage and deeper biomass accumulation. Physical crusts were least efficient in water conservation and erosion control, followed by non-crusted bare soils. More importantly, there were marked differences in the efficiency of the different spatial arrangements of bio-crusts in controlling runoff and sediment generation. Fully-covered bio-crust pattern provides the best option for soil loss reduction and runoff retention, while a combination of upper bio-crust and lower bare soil pattern is the least one. These findings are suggested to be significant for surface-cover protection, rainwater infiltration, runoff retention, and erosion control in water-restricted and degraded natural slopes.

  6. Bioindication of air pollution effects near a copper smelter in Brazil using mango trees and soil microbiological properties

    International Nuclear Information System (INIS)

    Klumpp, Andreas; Hintemann, Therese; Santana Lima, Josanidia; Kandeler, Ellen

    2003-01-01

    A field study near the copper smelter of a large industrial complex examined air pollution effects on vegetation and soil parameters in Camacari (northeast Brazil). Close to the smelter, soil pH-value was lower and total acidity as well as organic carbon contents were higher compared with a site far from the source and two reference sites. The acidification of top soil particularly and the drastically enhanced plant-available copper concentrations were caused by atmospheric deposition. High sulphur and copper deposition significantly reduced microbial biomass and altered functional diversity of soil microorganisms (arylsulphatase and xylanase). Large accumulations of sulphur, arsenic and copper were detected in mango leaves (Mangifera indica) growing downwind from the smelter suggesting potential food chain-mediated risk. - Atmospheric emissions in northeast Brazil have transformed soil pH, accumulated in soil and plants as sulphur and heavy metals, and affected the functional diversity of soil microorganisms

  7. Bioindication of air pollution effects near a copper smelter in Brazil using mango trees and soil microbiological properties

    Energy Technology Data Exchange (ETDEWEB)

    Klumpp, Andreas; Hintemann, Therese; Santana Lima, Josanidia; Kandeler, Ellen

    2003-12-01

    A field study near the copper smelter of a large industrial complex examined air pollution effects on vegetation and soil parameters in Camacari (northeast Brazil). Close to the smelter, soil pH-value was lower and total acidity as well as organic carbon contents were higher compared with a site far from the source and two reference sites. The acidification of top soil particularly and the drastically enhanced plant-available copper concentrations were caused by atmospheric deposition. High sulphur and copper deposition significantly reduced microbial biomass and altered functional diversity of soil microorganisms (arylsulphatase and xylanase). Large accumulations of sulphur, arsenic and copper were detected in mango leaves (Mangifera indica) growing downwind from the smelter suggesting potential food chain-mediated risk. - Atmospheric emissions in northeast Brazil have transformed soil pH, accumulated in soil and plants as sulphur and heavy metals, and affected the functional diversity of soil microorganisms.

  8. Using a passive air sampler to monitor air-soil exchange of organochlorine pesticides in the pasture of the central Tibetan Plateau.

    Science.gov (United Sta