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1

Susceptibility to Frost-Bite  

Directory of Open Access Journals (Sweden)

Full Text Available The body protects its susceptible parts e.g. hands and feet from cold injury by allowing a surge of blood to flow through them on exposure to severe cold. This occurs through alternate vasodilatation and vasoconstriction known as Lewis Hunting Reaction. This phenomenon is influenced by several factors, which indirectly may also affect individual susceptibility to cold injury. The role of nutrition, adequate insulation of the body and positive heat balance in relation to the protective mechanism have been reviewed and discussed. Available literature on various factors has been surveyed and discussed in the light of recent advances in the physiology of cold exposure. Certain tests based on the present knowledge, to be developed and standardised for screening susceptible individuals to frost-bite have been suggested.

Bal Krishna

2014-05-01

2

The effect of seasonal soil frost on the alpine groundwater recharge including climate change aspects  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In alpine areas, the snow cover plays an important role as a water reservoir. Water is stored as snow over the winter and released in spring, recharging mountain aquifers through infiltration. These aquifers are essential, especially for supplying water for human activities during dry seasons. Numerous studies have shown that locally soil frost can drastically reduce the water infiltration. However, we know much less about the hydrological impact of soil frost at a larger scale, in particular...

Bayard, Daniel

2003-01-01

3

Impacts of a water stress followed by an early frost event on beech (Fagus sylvatica L.) susceptibility to Scolytine ambrosia beetles - Research strategy and first results  

Science.gov (United States)

Climate change tends to induce more frequent abiotic and biotic extreme events, having large impacts on tree vitality. Weakened trees are then more susceptible to secondary insect outbreaks, as it happened in Belgium in the early 2000s: after an early frost event, secondary Scolytine ambrosia beetles attacks were observed on beech trees. In this study, we test if a combination of stress, i.e. a soil water deficit preceding an early frost, could render trees more attractive to beetles. An experimental study was set in autumn 2008. Two parcels of a beech forest were covered with plastic tents to induce a water stress by rain interception. The parcels were surrounded by 2-meters depth trenches to avoid water supply by streaming. Soil water content and different indicators of tree water use (sap flow, predawn leaf water potential, tree radial growth) were followed. In autumn 2010, artificial frost injuries will be inflicted to trees using dry ice. Trees attractivity for Scolytine insects, and the success of insect colonization will then be studied. The poster will focus on experiment setting and first results (impacts of soil water deficit on trees).

La Spina, Sylvie; de Cannière, Charles; Molenberg, Jean-Marc; Vincke, Caroline; Deman, Déborah; Grégoire, Jean-Claude

2010-05-01

4

Effects of freezing on soil temperature, frost propagation and moisture redistribution in peat: laboratory investigations  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of freezing on soil temperature and water movement were monitored in four peat Mesocosms subjected to bidirectional freezing. Temperature gradients were applied by bringing the Mesocosm tops in contact with sub-zero air temperature while maintaining a continuously frozen layer at the bottom (proxy permafrost. Soil water movement towards the freezing front (from warmer to colder regions was inferred from soil freezing curves and from the total water content of frozen core samples collected at the end of freezing cycle. This study illustrates how differences in initial water content influence the hydrologic functions of active layer in permafrost terrains covered with thick peat during soil freezing. A substantial amount of water, enough to raise the upper surface of frozen saturated soil within 15 cm of the soil surface at the end of freezing period, appeared to have moved upwards during freezing. Effects of temperature on soil matric potential, at least in the initial freezing period, appear to drive such movement as seen from analysis of soil freezing curves. Vapour movement from warmer to colder regions also appears to contribute in moisture movement. Frost propagation is controlled by latent heat for a long time during freezing. A simple conceptual model describing freezing of an organic active layer initially resembling a variable moisture landscape is proposed based upon the results of this study. The results of this study will help in understanding, and ultimately forecasting, the hydrologic response of wetland-dominated terrain underlain by discontinuous permafrost.

R. M. Nagare

2011-05-01

5

A preliminary synoptic assessment of soil frost on Marion Island and the possible consequences of climate change in a maritime sub-Antarctic environment  

Directory of Open Access Journals (Sweden)

Full Text Available Located in the sub-Antarctic, Marion Island (46° 54? S, 37° 45? E has a distinct periglacial environment that is sensitive to climate change. Diurnal soil frost is the most important geomorphic process occurring on the island and this paper aims to understand the synoptic weather circulation pattern associated with summer soil frost occurrence in a sub-Antarctic environment. Preliminary results from automated microclimate measurements in the interior of Marion Island show that summer soil frost is dependent on Antarctic air mass circulation. This occurs exclusively during post-cyclonic airflow after the passage of a cold front connected to a mid-latitudinal cyclone and subsequent ridging in of the South Atlantic Anticyclone behind the cold front, or when a series of low pressure systems passes over the island. The duration and intensity of soil frost cycles are dependent on the duration of post-cyclonic Antarctic air mass circulation. Summer soil frost on Marion Island is driven by a complex interaction between the latitudinal position of the passing cyclone, the latitudinal position of the ridging anticyclone as well as the trajectory of the air mass circulation. The data suggest that predicted trends in synoptic climate change in the sub-Antarctic may lead to non-linear responses in soil frost dynamics.

Werner Nel

2012-03-01

6

Water relation response to soil chilling of six olive (Olea europaea L.) cultivars with different frost resistance  

Energy Technology Data Exchange (ETDEWEB)

The relationship between the water relations of six olive cultivars exposed to different soil temperatures (14 0.1, 9.9 0.1 and 5.8 0.2 degree centigrade) and their inherent frost resistance (as determined by two different methods) was investigated. Soil chilling was achieved by introducing pots of olive plants into water baths. The water relations of these plants were compared to those of plants kept under conditions of room temperature. The cultivars Frantoio, Picual and Changlot Real began to show significant dehydration below 14 degree centigrade, while Cornicabra, Arbequina and Ascolana Tenera showed this below 10 degree centigrade. This response is probably due to delayed stomatal closure. Only Cornicabra and Picual showed a significant reduction in leaf conductance (below 10 degree centigrade and 6 degree centigrade respectively). This absence of stomatal control led to a significantly greater dehydration in Ascolana Tenera. These variations in response to the soil chilling temperature suggest that different mechanisms may be at work, and indicate that would be necessary to study the influence of rootstock in the frost resistance of olive plants. The variations recorded grouped the cultivars as either resistant (Cornicabra), tolerant (Picual, Ascolana Tenera and Arbequina), or sensitive (Frantoio and Changlot Real). This classification is in line with the frost resistance reported for these cultivars in the literature, and with the results obtained in the present work using the stomatal density and ion leakage methods of determining such resistance. (Author) 40 refs.

Perez-Lopez, D.; Gijon, M. C.; Marino, J.; Moriana, A.

2010-07-01

7

Full-scale chilled pipeline frost heave testing, Fairbanks, Alaska, USA  

Energy Technology Data Exchange (ETDEWEB)

This paper discussed a chilled pipeline frost-heave testing facility that was developed to simulate and record the rate of frost heave and frost-bulb growth for a buried, chilled pipeline in frost-susceptible soil and to determine the effectiveness of different mitigation techniques. The test facility, which was established near Fairbanks, Alaska, in 1979, has 10 test sections using 1.22-metre-diameter pipe. The testing involved un-insulated, insulated, and insulated with over-excavation and gravel berm configurations as well as the frost heave of the chilled pipeline. The test facility was described in detail. Frost heave and frost-bulb growth measurements from the first 10 months of testing were presented, as these are the first data to enter the public domain. The testing was undertaken to investigate the frost-heave relationships between sections, to better understand frost heave in permafrost, to explore possible mitigation options, and to advance the predicative capabilities of frost heave models. 12 refs., 1 tab., 17 figs.

Hazen, B. [Northern Engineering and Scientific, Anchorage, AK (United States); Isaacs, R.M. [RMI Associates, Camano Island, WA (United States); Myrick, J.E. [Myrick International, Tyler, TX (United States)

2010-07-01

8

Climate change impacts on hydrology of seasonal soil frost in the northern Midwestern United States  

Digital Repository Infrastructure Vision for European Research (DRIVER)

At global and regional scales, long-term changes in climate have been observed. Several studies have reported a sharp increase in global average air temperatures, with most of the warming happening in recent decades. Warming in air temperature has resulted in the reduction of frost days by up to two weeks and shorter winters in the Great Lakes region. Climate projections suggest that the Midwest will experience warmer air temperatures and a shift in precipitation from the summer into the wint...

Sinha, Tushar

2008-01-01

9

Non-stationary temporal characterization of the temperature profile of a soil exposed to frost in south-eastern Canada  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this work was to compare time and frequency fluctuations of air and soil temperatures (2-, 5-, 10-, 20- and 50-cm below the soil surface using the continuous wavelet transform, with a particular emphasis on the daily cycle. The analysis of wavelet power spectra and cross power spectra provided detailed non-stationary accounts with respect to frequencies (or periods and to time of the structure of the data and also of the relationships that exist between time series. For this particular application to the temperature profile of a soil exposed to frost, both the air temperature and the 2-cm depth soil temperature time series exhibited a dominant power peak at 1-d periodicity, prominent from spring to autumn. This feature was gradually damped as it propagated deeper into the soil and was weak for the 20-cm depth. Influence of the incoming solar radiation was also revealed in the wavelet power spectra analysis by a weaker intensity of the 1-d peak. The principal divergence between air and soil temperatures, besides damping, occurred in winter from the latent heat release associated to the freezing of the soil water and the insulation effect of snowpack that cease the dependence of the soil temperature to the air temperature. Attenuation and phase-shifting of the 1-d periodicity could be quantified through scale-averaged power spectra and time-lag estimations. Air temperature variance was only partly transferred to the 2-cm soil temperature time series and much less so to the 20-cm soil depth.

F. Anctil

2008-05-01

10

Frost heaving of planted tree seedlings in the boreal forest of northern Sweden  

International Nuclear Information System (INIS)

Frost heaving can be a leading cause of tree seedling mortality in many places in the boreal forest of Northern Sweden. The aim of this investigation was to improve our understanding of frost heaving of planted tree seedlings as related to snow cover, scarification, planting methods and soil types. The thesis is based on a review paper, three field experiments and one laboratory experiment. The experiments focus on different methods to control frost heaving of forest tree seedlings and on a number of factors affecting the extent of frost heaving. The review paper identifies the many aspects of frost heaving of forest tree seedlings and agricultural crops based on an intensive review of the research contributions made during the last century. Even if many investigations have been carried out with the aim to decrease the extent of frost heaving, very little quantitative results are available for tree seedlings. In a field experiment, the choice of planting positions was effective in decreasing frost heaving of planted seedlings following mounding or disc-trenching. Seedlings planted in the depressions were largely affected by frost heaving with a maximal vertical displacement of 5.4 cm while frost heaving did not occur on the top of the mound. On the other hand, the planting time and planting depth had no influence on the extent of frost heaving. In another field experiment the size of the scarified patches was strongly correlated to frost heaving which reached between 7.6 and 11.5 cm in 4 and 8-dm patches compared to between 4.4 and 5.3 in non-scarified soil and in a 1-dm patch. Ground vegetation probably decreases the diurnal temperature variation and the number of freezing-thawing cycles. The duration and magnitude of frost temperatures, the frost hour sum, increased with patch size. The difference between the 8-dm and 1-dm patch increased to 2064 hour-degrees at the end of the winter. In larger patches, the planting depth seemed to be effective in reducing the maximum frost heaving of the seedlings. In the third field experiment snow cover also showed to be an important factor in regard to frost heaving of tree seedlings. In a snow-free treatment combined with soil scarification, an uplift of 14.6 cm was measured during a winter season. In contrast no vertical displacement was observed under a simulated snow cover. The strong influence of snow on the extent of frost heaving indicates that further investigation should be focused on the interaction between maximum frost heaving and snow depth. In the laboratory freezing chamber experiment it was demonstrated that soil from spodic B horizon is less susceptible to frost heaving than soil from E horizon. Needle ice did not grow at all on soil samples from E horizon during a 3-day test, neither on fresh, nor on oven dried samples. On fresh samples of soil from Bs horizon, needle ices reached a maximum height of 9.7 cm in average. The use of theodolite and wooden dowels to estimate the extent of frost heaving in this study allowed to follow the process during the frost heaving period. A vertical uplift in millimetres could be recorded. A development of reliable measuring methods which allow a continuous estimation of the extent of frost heaving damage during the whole process, would undoubtedly represent an important step towards a better understanding of frost heaving of tree seedlings

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Frost heaving of planted tree seedlings in the boreal forest of northern Sweden  

Energy Technology Data Exchange (ETDEWEB)

Frost heaving can be a leading cause of tree seedling mortality in many places in the boreal forest of Northern Sweden. The aim of this investigation was to improve our understanding of frost heaving of planted tree seedlings as related to snow cover, scarification, planting methods and soil types. The thesis is based on a review paper, three field experiments and one laboratory experiment. The experiments focus on different methods to control frost heaving of forest tree seedlings and on a number of factors affecting the extent of frost heaving. The review paper identifies the many aspects of frost heaving of forest tree seedlings and agricultural crops based on an intensive review of the research contributions made during the last century. Even if many investigations have been carried out with the aim to decrease the extent of frost heaving, very little quantitative results are available for tree seedlings. In a field experiment, the choice of planting positions was effective in decreasing frost heaving of planted seedlings following mounding or disc-trenching. Seedlings planted in the depressions were largely affected by frost heaving with a maximal vertical displacement of 5.4 cm while frost heaving did not occur on the top of the mound. On the other hand, the planting time and planting depth had no influence on the extent of frost heaving. In another field experiment the size of the scarified patches was strongly correlated to frost heaving which reached between 7.6 and 11.5 cm in 4 and 8-dm patches compared to between 4.4 and 5.3 in non-scarified soil and in a 1-dm patch. Ground vegetation probably decreases the diurnal temperature variation and the number of freezing-thawing cycles. The duration and magnitude of frost temperatures, the frost hour sum, increased with patch size. The difference between the 8-dm and 1-dm patch increased to 2064 hour-degrees at the end of the winter. In larger patches, the planting depth seemed to be effective in reducing the maximum frost heaving of the seedlings. In the third field experiment snow cover also showed to be an important factor in regard to frost heaving of tree seedlings. In a snow-free treatment combined with soil scarification, an uplift of 14.6 cm was measured during a winter season. In contrast no vertical displacement was observed under a simulated snow cover. The strong influence of snow on the extent of frost heaving indicates that further investigation should be focused on the interaction between maximum frost heaving and snow depth. In the laboratory freezing chamber experiment it was demonstrated that soil from spodic B horizon is less susceptible to frost heaving than soil from E horizon. Needle ice did not grow at all on soil samples from E horizon during a 3-day test, neither on fresh, nor on oven dried samples. On fresh samples of soil from Bs horizon, needle ices reached a maximum height of 9.7 cm in average. The use of theodolite and wooden dowels to estimate the extent of frost heaving in this study allowed to follow the process during the frost heaving period. A vertical uplift in millimetres could be recorded. A development of reliable measuring methods which allow a continuous estimation of the extent of frost heaving damage during the whole process, would undoubtedly represent an important step towards a better understanding of frost heaving of tree seedlings.

Goulet, France

2000-07-01

12

Susceptibility of ectomycorrhizal fungi to soil heating.  

Science.gov (United States)

Ectomycorrhizal (EcM) fungi are an important biotic factor for successful tree recruitment because they enhance plant growth and alleviate drought stress of their hosts. Thus, EcM propagules are expected to be a key factor for forest regeneration after major disturbance events such as stand-replacing forest fires. Yet the susceptibility of soil-borne EcM fungi to heat is unclear. In this study, we investigated the heat tolerance of EcM fungi of Scots pine (Pinus sylvestris L., Pinaceae). Soil samples of three soil depths were heated to the temperature of 45, 60 and 70 °C, respectively, and surviving EcM fungi were assessed by a bioassay using Scots pine as an experimental host plant. EcM species were identified by a combination of morphotyping and sequencing of the ITS region. We found that mean number of species per sample was reduced by the 60 and 70 °C treatment, but not by the 45 °C treatment. Species composition changed due to heat. While some EcM fungi species did not survive heating, the majority of species was also found in the heated samples. The most frequent species in the heat treatment were Rhizopogon roseolus, Cenococcum geophilum and several unidentified species. PMID:20943157

Kipfer, Tabea; Egli, Simon; Ghazoul, Jaboury; Moser, Barbara; Wohlgemuth, Thomas

2010-01-01

13

Frost evolution in tailings  

International Nuclear Information System (INIS)

A review was carried out on the physical and thermal mechanisms of permafrost evaluation in soils and uranium tailings. The primary mechanism controlling permafrost evolution is conductive heat transfer with the latent heat of fusion of water being liberated as phase change occurs. Depending on the soil properties and freezing rate, pore water can be expelled from the frost front or pore water can migrate towards the frost front. Solute redistribution may occur as the frost front penetrates into the soil. The rate of frost penetration is a function of the thermal properties of the tailings and the climatic conditions. Computer modelling programmes capable of modelling permafrost evolution were reviewed. The GEOTHERM programme was selected as being the most appropriate for this study. The GEOTHERM programme uses the finite element method of thermal analysis. The ground surface temperature is determined by solving the energy balance equations a the ground surface. The GEOTHERM programme was used to simulate the permafrost evolution in the Key Lake Mine tailings located in north central Saskatchewan. The analyses indicated that the existing frozen zones in the tailing pond will eventually thaw if an average snow depth covers the tailings. Hundreds of years are required to thaw the tailings. If minimal snow cover is present the extent of the frozen zone in the tailings will increase

14

Effect of soil frost on growing season nitrogen uptake by fine roots of mature trees in northern hardwood forests of the United States  

Science.gov (United States)

Forests of the northeastern United States are predicted to experience a decrease in the depth and duration of the winter snowpack over the next 100 years. Even when coupled with warmer winter air temperatures, the absence of snow as insulation can increase soil frost during the winter months. Past research has determined that there are species-level effects of soil frost on dominant forest trees. For example, in stands dominated by sugar maple (Acer saccharum), induced soil frost led to increased fine root mortality and soil nitrate leaching. Soil frost also increased fine root mortality in stands dominated by yellow birch (Betula allegheniensis), but there was no significant change in leaching of soil nitrate. We hypothesized that greater nitrogen (N) losses from stands dominated by sugar maple may be due to reduced N uptake by fine roots of this tree species. To determine the impact of increased soil freezing on fine root uptake of N, we established a snow manipulation experiment in mixed sugar maple/American beech (Fagus grandifolia) forests at the Hubbard Brook Experimental Forest in New Hampshire (n=4 paired snow-removal and reference plots; each 13m X 13m). Snow removal occurred during the first six weeks of winter over two years. During each growing season following snow removal, we used the N depletion technique to measure in situ rates of uptake of ammonium and nitrate by fine roots of sugar maple during the early, peak and late growing season. Among all sampling dates and plots, we observed significantly lower uptake of N as nitrate compared to ammonium. During the first growing season, at moderate ammonium availability (35 ?M N) we observed significantly less uptake of ammonium by fine roots of sugar maple in the snow removal plots relative to the reference plots during the early growing season (April-May), with no significant differences in uptake of ammonium during the peak (July) and late (September) growing season. We observed no differences in uptake of ammonium among the snow removal and references plots at higher ammonium availability (200 ?M N), nor nitrate at either concentration throughout the growing season. Results of our study suggest that the observed increase in N losses following periods of soil frost could be due to a decrease in N uptake by fine roots of mature trees, especially in the early growing season. Our study shows the effects of vegetation responses to climate change on ecosystem nitrogen cycling.

Socci, A. M.; Templer, P. H.

2010-12-01

15

The influence of soil type on the magnetic susceptibility measured throughout soil profiles  

Science.gov (United States)

The interpretation of soil susceptibility measurements depends on knowledge of a reference value. This reference value will be influenced by the type of soil. In the present study, data of various soil types, which formed on diverse parent material, are analysed. As the same data set has been used in a soil pollution study, we are able to estimate and exclude the influence of pollution. Susceptibility values of unpolluted soils turn out to significantly depend on the soil type. Chernozem samples yield the highest susceptibility values of the analysed soil types (50-90 × 10-8 m3 kg-1). Cambisol displays intermediate values (20-60 × 10-8 m3 kg-1) and waterlogged soils have the lowest values (5-20 × 10-8 m3 kg-1). The enrichment of topsoil susceptibility (0-20 cm depth) compared to subsoil susceptibility (40-50 cm depth) depends more on the parent material than on the soil type. Given the comparability of soil type and parent material, the values of this study can be used to identify soils with unusual susceptibility values, which may be further analysed in order to pinpoint soil pollution.

Hanesch, M.; Scholger, R.

2005-04-01

16

Investigation of effects of moisture on soil temperature regimes and frost depth in a laboratory model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Freezing depth is one the most important climatic parameters for indices applied in various fields such as agriculture and civil engineering. The parameter of freezing depth depends on different factors including astronomical, surface air temperature, humidity; soil characteristics such as texture, heat capacity, thermal conductivity and specific heat. This study investigated the effect of air temperature on freezing depth. Apparatus able to reach temperatures of -16 ?C was set up to test so...

Et Al, Rahnama Yami E.

2012-01-01

17

Soil susceptibility to acidification; 1 : 1 000 000  

International Nuclear Information System (INIS)

The capacity of soils to resist to acidification depends on the content of carbonates, humus, clayey minerals, and salts. The least prone to acidification are the carbonate and alkaline soils where the pH does not significantly change (the carbonate controlling system). The soils pertaining to different soil units (carbonate Chernozems, Histi-Mollic Gleysols, Fluvisols, Rendzinas, Solonchals and Solonetzs) are in this group. On the other side, there are the very washed out (leached) soils of mountain areas where pH does not change significantly due to their extreme acidity (aluminium controlling system). Four classes of soils with different susceptibility to acidification depending on their buffer capacities controlled by the content of clay, humus and basic ions are classified into this group. Very sensitive (prone to acidification) are the light sandy soils with low content of humus and clay where pH in slightly acid to neutral areas is maintained by calcification and fertilisation. (author)

18

Reduction in soil loss from erosion-susceptible soils amended with humic substances from oxidized coal  

International Nuclear Information System (INIS)

Soils that pose high risk of erosion require amendment with either natural or synthetic soil conditioners to reduce soil loss hazards. The objective of this study was to evaluate the potential of using coal-derived humic substances (as soil conditioners) to reduce runoff erosion on erosion-susceptible soils. Surface samples of severely degraded soils from Principina in Tuscany and Bovolone in Venice in Italy were used to assess the effects of five rates (0, 0.05, 0.01, 0.50 and 1.00 g/kg) of humic acids (HA) on soil loss and other hydrological parameters. The results showed that amending erosion-susceptible soils with low rates of coal-derived humic substances is a potentially effective soil management practice for reducing erosion rates

19

Frost formation and ice adhesion on superhydrophobic surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study frost formation and its impact on icephobic properties of superhydrophobic surfaces. Using an environmental scanning electron microscope, we show that frost nucleation occurs indiscriminately on superhydrophobic textures without any particular spatial preference. Ice adhesion measurements on superhydrophobic surfaces susceptible to frost formation show increased adhesion over smooth surfaces with a strong linear trend with the total surface area. These studies indicate that frost for...

Varanasi, Kripa K.; Deng, Tao; Hsu, Ming; Bhate, Nitin; Smith, Jonathan David

2010-01-01

20

Magnetic susceptibility properties of pesticide contaminated volcanic soil  

Science.gov (United States)

Pesticides, unfortunately, are still widely used in many countries as way to eradicate agricultural pests. As they are being used continuously over a long period of time, they accumulate as residues in soils posing serious threats to the environment. In this study, we study the changes in magnetite-rich volcanic soils that were deliberately contaminated by pesticide. Such changes, in any, would be useful in the detection of pesticide residue in contaminated soils. Two different types of magnetically strong volcanic soil from the area near Lembang, West Java, Indonesia were used in this study where they were contaminated with varying concentrations of pesticide. The samples were then measured for magnetic susceptibility at two different frequencies. The measurements were then repeated after a period of three months. We found a reduction of magnetic susceptibility as well as a reduction in SP (superparamagnetic) grains proportion in contaminated soil. These might be caused by pesticide-induced magnetic dissolution as supported by SEM analyses. However the impact of pesticide concentration as well as exposure time on magnetic dissolution is still inconclusive.

Agustine, Eleonora; Fitriani, Dini; Safiuddin, La Ode; Tamuntuan, Gerald; Bijaksana, Satria

2013-09-01

 
 
 
 
21

Machine learning modelling for predicting soil liquefaction susceptibility  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study describes two machine learning techniques applied to predict liquefaction susceptibility of soil based on the standard penetration test (SPT) data from the 1999 Chi-Chi, Taiwan earthquake. The first machine learning technique which uses Artificial Neural Network (ANN) based on multi-layer perceptions (MLP) that are trained with Levenberg-Marquardt backpropagation algorithm. The second machine learning technique uses the Support Vector machine (SVM) that is firmly based on the theor...

Samui, P.; Sitharam, T. G.

2011-01-01

22

Soil Liquefaction Susceptibility and Site Class Maps of Washington State  

Science.gov (United States)

In response to the Nisqually earthquake of 2001, the Washington State Division of Geology and Earth Resources (DGER) developed two types of earthquake hazard maps for every county in the state: liquefaction susceptibility maps, which outline areas where water-saturated sandy soil loses strength during earthquake shaking, and National Earthquake Hazards Reduction Program (NEHRP) site class maps, which outline areas where soils amplify ground shaking. The maps will be used by state and local governments in Washington to update existing hazard mitigation plans and to delineate geologically hazardous areas for emergency planning and response, planning of local zoning ordinances, and building code enforcement. A link is provided to an ftp site where the maps are stored in folders.

23

Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes  

Science.gov (United States)

Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 ?? 10-5 SI) than adjacent to floodplain or lowland tree species (17 ?? 10-5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species' flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species' flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation. ?? 2007 Elsevier B.V. All rights reserved.

Wang, J.-S.; Grimley, D.A.; Xu, C.; Dawson, J.O.

2008-01-01

24

Machine learning modelling for predicting soil liquefaction susceptibility  

Directory of Open Access Journals (Sweden)

Full Text Available This study describes two machine learning techniques applied to predict liquefaction susceptibility of soil based on the standard penetration test (SPT data from the 1999 Chi-Chi, Taiwan earthquake. The first machine learning technique which uses Artificial Neural Network (ANN based on multi-layer perceptions (MLP that are trained with Levenberg-Marquardt backpropagation algorithm. The second machine learning technique uses the Support Vector machine (SVM that is firmly based on the theory of statistical learning theory, uses classification technique. ANN and SVM have been developed to predict liquefaction susceptibility using corrected SPT [(N160] and cyclic stress ratio (CSR. Further, an attempt has been made to simplify the models, requiring only the two parameters [(N160 and peck ground acceleration (amax/g], for the prediction of liquefaction susceptibility. The developed ANN and SVM models have also been applied to different case histories available globally. The paper also highlights the capability of the SVM over the ANN models.

P. Samui

2011-01-01

25

Frost risks in the Mantaro river basin  

Directory of Open Access Journals (Sweden)

Full Text Available As part of the study on the Mantaro river basin's (central Andes of Perú current vulnerability to climate change, the temporal and spatial characteristics of frosts were analysed. These characteristics included intensity, frequency, duration, frost-free periods, area distribution and historical trends. Maps of frost risk were determined for the entire river basin, by means of mathematical algorithms and GIS (Geographic Information Systems tools, using minimum temperature – 1960 to 2002 period, geomorphology, slope, land-use, types of soils, vegetation and life zones, emphasizing the rainy season (September to April, when the impacts of frost on agriculture are most severe. We recognized four categories of frost risks: low, moderate, high and critical. The critical risks (with a very high probability of occurrence were related to high altitudes on the basin (altitudes higher than 3800 m a.s.l., while the low (or null probability of occurring risks were found in the lower zones (less than 2500 m a.s.l.. Because of the very intense agricultural activity and the high sensitivity of the main crops (Maize, potato, artichoke in the Mantaro valley (altitudes between 3100 and 3300 m a.s.l., moderate to high frost risks can be expected, with a low to moderate probability of occurrence. Another significant result was a positive trend of 8 days per decade in the number of frost days during the rainy season.

G. Trasmonte

2008-04-01

26

Frost/Nixon  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This project investigates power relations’ constitution through interaction in an institutionalised news interview setting. Two objects, The Nixon Interviews and Frost/Nixon, have been analysed to explore this. The objects are an interview with former President Richard Nixon, conducted by the British journalist David Frost and the film, adapted from a stage play, based on said interviews. Comparing these two concludes how participants in both the original and fictionalised interviews consti...

Hvid, Amanda Boie; Rasmussen, Lasse Duus; Birkemose, Liv; Myssen, Martin; Augoustakis, Louisa Dikea

2013-01-01

27

Mapping soil erosion using magnetic susceptibility. A case study in Ukraine  

Directory of Open Access Journals (Sweden)

Full Text Available The intrinsic element grouping of the magnetic susceptibility (MS values is conducted. The relation between MS values and erosion index is shown. The objective of the investigation is study of the information about magnetic susceptibility of soils as a diagnostic criterion to erodibility. The investigations were conducted in the limits of Tcherkascy Tishki territory, Kharkiv district. The soils of the territory are presented by catenary row of chernozems. The study area was used in the field crop rotation. The soil conservation technologies have not been applied. The data analyze confirmed high correlation of the MS, erosive index and humus content. The possibility of MS cartogram using at the soil erodibility map is presented. The magnetic methods can be extensively used at the soil erosion investigations thanks to the speed and low cost.

P. Nazarok

2014-03-01

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Tints, Shades and Frost  

Science.gov (United States)

This article describes a classroom art project inspired by the work of Robert Frost, one of the most acclaimed and beloved American poets of all time. Using tints and shades in a composition, this project demonstrates how quality literature may be incorporated into elementary art lessons in a very useful way, making art an important complement to…

Sterling, Joan

2009-01-01

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A passive solar water heating system for vineyard frost protection  

Energy Technology Data Exchange (ETDEWEB)

The threat of frost during spring time (after 'bud burst') is an ever present danger to the vineyard owner. To minimise the risk, in addition to good site selection and vineyard management, a number of active frost protection systems are available. Most active methods of frost protection are costly in monetary terms and can also have a detrimental effect on the environment. This work presents the design and performance of a passive solar water heating quilt system under real vineyard operating conditions. Two vineyard sites were selected, and the solar water heating quilt design was evaluated over a three-month period. Detailed measurements of the temperature below and above the soil surface, levels of incident solar radiation and the wind direction and speed were recorded. Field study results indicate that the quilts can improve the solar collection and heat retention of the soil, resulting in increased temperatures during frost events of up to 1 C in air space immediately adjacent to the solar quilts when compared to conditions off the protected area. In addition, the time period during which the frost remains a danger to the vine is also reduced. When heat collection, storage and extraction rates are investigated, simplified calculations indicate that the solar quilt can improve collection by 38.5% over bare soil, resulting in the release of 32% more heat. Extrapolated to vineyard coverage, this could result in an extra 3500 MJ of heat per hectare per (typical frost event condition) day. (author)

Smyth, M. [Centre for Sustainable Technologies, School of the Built Environment, University of Ulster, Newtownabbey BT37 0QB (Ireland); Skates, H. [Environmental Engineering Research Centre, School of Planning, Architecture and Civil Engineering, Queen' s University, Belfast BT9 5AG (Ireland)

2009-03-15

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Hydrocarbon microseepage and magnetic susceptibility of soils: Field tests and magnetic mineralogy  

Energy Technology Data Exchange (ETDEWEB)

Field and rock magnetic studies are undertaken to test the hypothesis that hydrocarbon microseepage can cause anomalous increases in soil magnetic susceptibility and to investigate the nature of the magnetic phases involved. A soil magnetic survey in southern Michigan in the vicinity of the Albion-Scipio and Stoney Point fields indicates a persistent elongate ring anomaly extending for several miles. This anomaly was drilled in 1993 without encountering adequate reservoir rock although gas shows were noted. The soils over a gas storage field in Michigan contain a marked positive anomaly which closely follows the edge of the storage field in many areas. Gas storage or other pressure production than older partially depleted fields which may show a muted seepage profile. Rock magnetic studies indicate that magnetite and possibly pyhrrotite are the magnetic carriers for some soils with susceptibility anomalies. Hysteresis loops indicate that most soil samples contain very fine grained superparamagnetic phases. The results of these studies as well as other previously completed investigations indicate that microseeping hydrocarbons can cause soil susceptibility anomalies that reside in magnetite. The mechanism of magnetite formation is still open to question and could involve inorganic processes and/or bacterial activity.

Fruit, D.; Downing, R.K. [Tier Hydrocarbon Exploration, Oklahoma City, OK (United States); Elmore, R.D. [Univ. of Oklahoma, Norman, OK (United States)] [and others

1995-06-01

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The influence of flat residue loss by wind on soil wind erosion susceptibility  

Science.gov (United States)

Flat crop residue often contributes to wind erosion control, but it may be rearranged or removed from fields during high wind events. This paper reports the influence of flat residue loss on soil wind erosion susceptibility when standing stems co-existed. Data were collected in laboratory wind tunne...

32

Frost resistance of reproductive tissues during various stages of development in high mountain plants.  

Science.gov (United States)

Frost resistance of reproductive vs aboveground vegetative structures was determined for six common European high alpine plant species that can be exposed to frosts throughout their whole reproductive cycle. Freezing tests were carried out in the bud, anthesis and fruit stage. Stigma and style, ovary, placenta, ovule, flower stalk/peduncle and, in Ranunculus glacialis, the receptacle were separately investigated. In all species, the vegetative organs tolerated on an average 2-5 K lower freezing temperatures than the most frost-susceptible reproductive structures that differed in their frost resistance. In almost all species, stigma, style and the flower stalk/peduncle were the most frost-susceptible reproductive structures. Initial frost damage (LT??) to the most susceptible reproductive structure usually occurred between -2 and -4°C independent of the reproductive stage. The median LT?? across species for stigma and style ranged between -3.4 and -3.7°C and matched the mean ice nucleation temperature (-3.7 ± 1.4°C). In R. glacialis, the flower stalk was the most frost-susceptible structure (-5.4°C), and was in contrast to the other species ice-tolerant. The ovule and the placenta were usually the most frost-resistant structures. During reproductive development, frost resistance (LT??) of single reproductive structures mostly showed no significant change. However, significant increases or decreases were also observed (2.1 ± 1.2 K). Reproductive tissues of nival species generally tolerated lower temperatures than species occurring in the alpine zone. The low frost resistance of reproductive structures before, during and shortly after anthesis increases the probability of frost damage and thus, may restrict successful sexual plant reproduction with increasing altitude. PMID:22420836

Neuner, Gilbert; Erler, Agnes; Ladinig, Ursula; Hacker, Jürgen; Wagner, Johanna

2013-01-01

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GEMAS: A unique data set to define magnetic susceptibility variability of European agricultural soil  

Science.gov (United States)

The GEMAS data set provides the first comprehensive overview of magnetic susceptibility in European soil. Samples from the upper 20cm were taken in large agricultural fields (Ap-sample). After air drying and sieving to chromic luvisols (terra rossa). On the European scale a unique signal of anthropogenic enhancement of k in Ap soil cannot be distinguished. All major features of the k distribution can be related to geology. Thereby, the GEMAS data set of magnetic susceptibility provides a continent wide reference of the natural background of k in Ap soil. It can be used to define the geological background variability for national and local studies, where this knowledge is needed to distinguish between anthropogenic and geogenic sources of observed k anomalies.

Fabian, Karl; Reimann, Clemens

2014-05-01

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Magnetic susceptibility and heavy metals contamination in soils of Southern Poland  

Science.gov (United States)

The anthropogenic character of the increase in magnetic susceptibility of Silesian soils is doubtless. The dependence between the magnetic susceptibility of industrial dust and the concentration of heavy metals was investigated. Correlation coefficients between those two parameters range for metallurgic dust from 0.911 to 0.998 for Ni and Zn, for fly ashes from 0.710 to 0.820, for Pb and Zn, for cement dust from 0.261 to 0.519 for Ni and Pb, respectively. The anthropogenic character of this dependence is also confirmed by the values of the correlation coefficients between magnetic susceptibility and dust emission, fly ash, metallurgic dust, cement dust, are 0.903, 0.867, 0.918 and 0.365, respectively. For immission the correlation coefficients are as follow: 0.817, 0.656, 0.440 for dustfall, suspended dust and iron fall, respectively. In magnetic particles selected from fly ashes high concentrations of Pb, Zn, Ni and Cu were found. Regarding dependence of magnetic susceptibility on concentration of heavy metals in soils Upper Silesian Industrial Region the correltion coefficients were: between 0.616 - 0.986 for Zn, 0.724 - 0.979 for Pb, and 0.175 - 0.581 for Cd. These values were lower for 90 soil profiles collected from an area of 22 000 km 2 (Katowice Forest State Directorate) resulting from varying conditions of emission and immission of industrial pollutants.

Strzyszcz, Z.; Magiera, T.

35

Magnetic susceptibility and the spatial variability of heavy metals in soils developed on basalt  

Science.gov (United States)

Topsoil magnetic susceptibility (?) is a fast and convenient method used to detect potentially polluted areas by heavy metals. Topsoil measurements are carried out in situ with Bartington MS2D loop sensor, designed to measure the magnetic susceptibility of top 10 cm of soil and detect 90% of the total signal from a depth of 6 cm. However, soils developed on basalt are difficult to assess due to their large amounts of ferrimagnetic minerals. The aim of this study was evaluate the applicability of ? to discriminate anthropogenic/lithogenic environments characterized by different parent materials in the city of Maringá/Brazil. In this paper, topsoil susceptibility (?) was measured in 66 urban soils using a Bartington MS2D loop sensor. To investigate the magnetic background levels, samples of a Rhodic Ferralsol profile were measured using a laboratory MS2B sensor. X-ray diffractometry (XRD) analysis was carried out to verify the mineralogical composition of the different lithology. Cu, Fe, Ni, Mn, Pb and Zn concentrations were measured in 29 topsoil samples. The ? values ranged from 316 × 10- 5 SI in a sandstone region to 6,945 × 10- 5 SI in soils developed on basalt. The ?fd values of urban topsoil varied from 2% to 11.3%. Lower values of ? and ?fd in the sandstone region indicated that the lithogenic contribution is of primary significance. Significant positive correlations between ? and Cu, Fe and Mn are related to the parent material, enriched in iron oxides, as verified by XRD. The background values (mean of 4,235 × 10- 8 m3 kg- 1) were higher in subsoil, suggesting the inexistence of anthropogenic pollution. The topsoil susceptibility was efficient for distinguish different lithogenic environments. Although anthropogenic pollution in soils developed on basalt is difficult to assess due to the high natural background, our results suggest that heavy metal contents are not related to the human activity.

Cervi, Eduardo Cimino; da Costa, Antonio Carlos Saraiva; de Souza Junior, Ivan Granemann

2014-12-01

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Magnetic Susceptibility and Geochemistry of Soils and Alluvial Sediments in the Area of Vistula River Delta (N Poland).  

Science.gov (United States)

Magnetic iron minerals, whose presence in soils can easily be detected by magnetic susceptibility measurements, are components of numerous industrial dusts. There is a linear dependence between magnetic particles content and content of heavy metals like: Cu, Fe, Pb and Zn (in urban dusts). A similar dependence was observed in atmospheric dusts (for Pb, Cu, Zn, and Cd). If the origin of magnetic particles and a considerable part of heavy metals permeating into soils as a result of industrial emission or imission is the same, the application of magnetic susceptibility measurements for the detection of potential high risk-areas is possible. Studies of magnetic susceptibility of alluvial sediments, beach sands, soils and subsoils were conducted in the area of Vistula river delta (N Poland). Maps of magnetic susceptibility were prepared basing on laboratory measurements, using Bartington MS2 device. The magnetic susceptibility pattern was compared and correlated with available geochemical determinations that were elaborated for the same sample set. Positive correlation is observed between magnetic susceptibility of topsoils and such elements as Ba, Co, Mg, Mn and Ni. Differential map, constructed as a difference between maps of topsoils and subsoils, might be a useful tool for preliminary detection of heavy metal pollution in soils. Negative anomaly observed at this kind of map suggests natural origin of increased susceptibility. A direct link between lithology of surrounding bedrocks and susceptibility values of soils and alluvial sediments is evident. A very high values of magnetic susceptibility reflect anthropogenic pollution of soils in the areas of big cities and industrial centrums. There is no such relationship in the case of magnetic susceptibility of alluvial sediments. The anthropogenic pressure is cumulated in the coastal zone of the Baltic Sea, where alluvial and beach sediments display the highest values of magnetic susceptibility.

Nawrocki, J.; Polechoñska, O.

2007-12-01

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ISOLATION AND ANTIBIOTIC SUSCEPTIBILITY TESTING OF RAPIDLY-GROWING MYCOBACTERIA FROM GRASSLAND SOILS  

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Full Text Available Rapidly growing mycobacteria (RGM are common soil saprophytes, but certain strains cause infections in human and animals. The infections due to RGM have been increasing in past decades and are often difficult to treat. The susceptibility to antibiotics is regularly evaluated in clinical isolates of RGM, but the data on soil RGM are missing. The objectives of this study was to isolate RGM from four grassland soils with different impact of manuring, and assess their resistance to antibiotics and the ability to grow at 37°C and 42°C. Since isolation of RGM from soil is a challenge, a conventional decontamination method (NaOH/malachite green/cycloheximide and a recent method based on olive oil/SDS demulsification were compared. The olive oil/SDS method was less efficient, mainly because of the emulsion instability and plate overgrowing with other bacteria. Altogether, 44 isolates were obtained and 23 representatives of different RGM genotypes were screened. The number of isolates per soil decreased with increasing soil pH, consistently with previous findings that mycobacteria were more abundant in low pH soils. Most of the isolates belonged to the Mycobacterium fortuitum group. The majority of isolates was resistant to 2-4 antibiotics. Multiresistant strains occurred also in a control soil that has a long history without the exposure to antibiotic-containing manure. Seven isolates grew at 37°C, including the species M. septicum and M. fortuitum known for infections in humans. This study shows that multiresistant RGM close to known human pathogens occur in grassland soils regardless the soil history of manuring.

Martina Kyselková

2013-08-01

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Susceptibility of coarse-textured soils to soil erosion by water in the tropics  

International Nuclear Information System (INIS)

The application of soil physics for the evaluation of factors of soil erosion in the tropics received considerable attention in the last four decades. In Nigeria, physical characteristics of rainfall such as drop size and drop-size distribution, rainfall intensity at short intervals and kinetic energy of rainfall were evaluated using different methods. Thus, compound erosivity indices were evaluated which showed a similar trend in annual rainfall erosivity with annual rainfall amounts. Attempts have also been made to use geostatistical tools and fractal theory to describe temporal variability in rainfall erosivity. High erosivity aggravates the vulnerability of coarse-textured soils to erosion. These soils, high in sand content were poorly aggregated and structurally weak. Thus, they were easily detached and transported by runoff. Long-term data are needed to describe factors of soil erosion in the tropics but quite often, equipment are not available or poorly maintained where available such that useful data are not collected. A greater cooperation of pure physicists, soil physicists and engineers in the developing nations is needed to improve or design equipment and methods for the characterization of factors of soil erosion in the tropics. (author)

39

Identification of soil bacteria susceptible to TiO2 and ZnO nanoparticles.  

Science.gov (United States)

Because soil is expected to be a major sink for engineered nanoparticles (ENPs) released to the environment, the effects of ENPs on soil processes and the organisms that carry them out should be understood. DNA-based fingerprinting analyses have shown that ENPs alter soil bacterial communities, but specific taxon changes remain unknown. We used bar-coded pyrosequencing to explore the responses of diverse bacterial taxa to two widely used ENPs, nano-TiO(2) and nano-ZnO, at various doses (0, 0.5, 1.0, and 2.0 mg g(-1) soil for TiO(2); 0.05, 0.1, and 0.5 mg g(-1) soil for ZnO) in incubated soil microcosms. These ENPs significantly altered the bacterial communities in a dose-dependent manner, with some taxa increasing as a proportion of the community, but more taxa decreasing, indicating that effects mostly reduced diversity. Some of the declining taxa are known to be associated with nitrogen fixation (Rhizobiales, Bradyrhizobiaceae, and Bradyrhizobium) and methane oxidation (Methylobacteriaceae), while some positively impacted taxa are known to be associated with the decomposition of recalcitrant organic pollutants (Sphingomonadaceae) and biopolymers including protein (Streptomycetaceae and Streptomyces), indicating potential consequences to ecosystem-scale processes. The latter was suggested by a positive correlation between protease activity and the relative abundance of Streptomycetaceae (R = 0.49, P = 0.000) and Streptomyces (R = 0.47, P = 0.000). Our results demonstrate that some metal oxide nanoparticles could affect soil bacterial communities and associated processes through effects on susceptible, narrow-function bacterial taxa. PMID:22798374

Ge, Yuan; Schimel, Joshua P; Holden, Patricia A

2012-09-01

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Differential susceptibility of some sunflower genotypes to phosphorus deficiency in a black soil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In a pot culture study, using phosphorus deficient black soil, four promising sunflower genotypes (KBSH-1, DSH-1, Sungene-85 and PAC-36) were tested for their differential susceptibility to the deficiency of this nutrient. Phosphorus deficiency symptoms were noticed in the hybrids KBSH-1 and DSH-1 while PAC-36 was almost free from these. The maximum grain yield response to phosphorus was recorded in KBSH-1 and the minimum in PAC- 36. Dry matter yield followed a similar trend. On the basis of ...

Dharudu Murali Y.; Murthy I.Y.L.N.; Ch, Haripriya V.

2003-01-01

 
 
 
 
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Mapping soil erosion susceptibility using GIS techniques within the Danube floodplain, the Calafat - Turnu M?gurele sector (Romania  

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Full Text Available The Danube floodplain, the Calafat - Turnu M?gurele sector, through its main features (topographic and climatic characteristics, land use and soil type and human activities, constitutes an area exposed to soil erosion. The main objective of the present research is to map soil erosion susceptibility using the GIS techniques for the computation and representation of areas, which are exposed to soil erosion correlated with the field data for the validation. Analyzing the entire model, the relatively simple methodology, the database consistence, the comparability of the results with the existent soil erosion values at national and local scale, we can say that the model was applied with success in the studied area (areas and classes of water erosion susceptibility: very low, low, moderate, high - Ciupercenii Noi, Desa, M?ce?u de Jos, Grojdibodu, Orlea, very high - Rast, Negoi, Catane, Bistre?, Goicea; areas and classes of wind erosion susceptibility: very low, low, moderate - Ciupercenii Noi, D?buleni, Ianca, high - Calafat, Poiana Mare, Desa, Goicea, Piscu Vechi, very high - Poiana Mare, Rast, Negoi, Bistre?, Gighera, Orlea. The soil erosion susceptibility map can be useful for planning erosion control measures and for selecting suitable sites for runoff plot experiments.

Ionu? Oana

2013-01-01

42

Tolerância de frutos de pessegueiro a geadas / Fruit frost tolerance in peach  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho teve como objetivo avaliar a tolerância de frutos de pessegueiro aos danos ocasionados pela geada. A geada ocorreu no dia 5 de setembro de 2006, sendo que a temperatura mínima, a 1,5 m do solo, foi de - 1,06ºC. Foram avaliados 28 genótipos de pessegueiro em diferentes estádios fenológi [...] cos. O delineamento experimental foi o inteiramente casualizado, com três repetições (plantas de pessegueiro), procedendo-se à avaliação em seis ramos por planta. No dia em que ocorreu a geada, foram mensurados o número de frutos por ramo, diâmetro sutural médio dos frutos, número total de gemas vegetativas, percentual de brotação e percentual de brindilas formadas a partir das gemas brotadas. Uma segunda avaliação foi realizada 15 dias após a primeira, para avaliar o percentual de queda de frutos e o diâmetro sutural médio dos frutos remanescentes. Genótipos bem enfolhados e cujos frutos apresentavam endocarpo endurecido, no momento da ocorrência da geada, foram tolerantes ao dano ocasionado pelo frio; frutos com diâmetro sutural inferior a 20 mm foram suscetíveis à geada, enquanto frutos com diâmetro sutural superior a 30 mm apresentaram boa tolerância, independentemente do genótipo avaliado. Abstract in english The aim of this work was to evaluate the fruit damage tolerance in different peach tree genotypes after natural freeze. The frost happened on September 5, 2006, and the minimum temperature, 1.5 meters over soil, was -1.06ºC. Twenty- eight peach tree genotypes, in different stages of development, wer [...] e evaluated, in a completely random design, in three replication (plants) and six branches by plants. Immediately after frost, we measured the number of fruits per branches, average fruit suture diameter, percentage of sprouts and percentage of twigs in formation. A second evaluation was accomplished fifteen days after the first one in order to assess the percentage of fruit drop and the average remaining fruit suture diameter. Genotypes with good leafing and hard pit (endocarp) during frost have freeze tolerance; fruits with suture diameter lass than 20 mm are susceptible to frost damage, while fruits with suture diameter superior to 30 mm are tolerant.

André Paulo, Assmann; Idemir, Citadin; Mauro Cristovão, Locatelli; Silvia, Scariot; Moeses Andrigo, Danner; Maria do Carmo Bassols, Raseira.

1030-10-01

43

Tolerância de frutos de pessegueiro a geadas Fruit frost tolerance in peach  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho teve como objetivo avaliar a tolerância de frutos de pessegueiro aos danos ocasionados pela geada. A geada ocorreu no dia 5 de setembro de 2006, sendo que a temperatura mínima, a 1,5 m do solo, foi de - 1,06ºC. Foram avaliados 28 genótipos de pessegueiro em diferentes estádios fenológicos. O delineamento experimental foi o inteiramente casualizado, com três repetições (plantas de pessegueiro, procedendo-se à avaliação em seis ramos por planta. No dia em que ocorreu a geada, foram mensurados o número de frutos por ramo, diâmetro sutural médio dos frutos, número total de gemas vegetativas, percentual de brotação e percentual de brindilas formadas a partir das gemas brotadas. Uma segunda avaliação foi realizada 15 dias após a primeira, para avaliar o percentual de queda de frutos e o diâmetro sutural médio dos frutos remanescentes. Genótipos bem enfolhados e cujos frutos apresentavam endocarpo endurecido, no momento da ocorrência da geada, foram tolerantes ao dano ocasionado pelo frio; frutos com diâmetro sutural inferior a 20 mm foram suscetíveis à geada, enquanto frutos com diâmetro sutural superior a 30 mm apresentaram boa tolerância, independentemente do genótipo avaliado.The aim of this work was to evaluate the fruit damage tolerance in different peach tree genotypes after natural freeze. The frost happened on September 5, 2006, and the minimum temperature, 1.5 meters over soil, was -1.06ºC. Twenty- eight peach tree genotypes, in different stages of development, were evaluated, in a completely random design, in three replication (plants and six branches by plants. Immediately after frost, we measured the number of fruits per branches, average fruit suture diameter, percentage of sprouts and percentage of twigs in formation. A second evaluation was accomplished fifteen days after the first one in order to assess the percentage of fruit drop and the average remaining fruit suture diameter. Genotypes with good leafing and hard pit (endocarp during frost have freeze tolerance; fruits with suture diameter lass than 20 mm are susceptible to frost damage, while fruits with suture diameter superior to 30 mm are tolerant.

André Paulo Assmann

2008-12-01

44

Cave development by frost weathering  

Science.gov (United States)

This paper deals with the description and genesis of a special type of shelter cave. In German they are termed Auswitterungshöhlen which goes back to the 19th century and the genesis is supposed to be related to frost weathering, but to our knowledge, detailed studies are missing so far. This type of cave is very common in the area of investigation that comprises pre-Alpine and Alpine regions in the north-eastern part of the Eastern Alps: They make up 32% of the 5138 registered caves but surprisingly they entirely developed in carbonate rocks. Although most of them are smaller than a dozen metres, some have lengths of more than 50 m and entrances can be more than 100 m wide or similarly high. Besides general observations that lead to a list of characteristics for these caves, two of them in a pre-Alpine setting were studied in-depth. A detailed map, descriptions, and measurements concerning cave morphology, host rock geology, and climate are given. The thickness and composition of clastic sediments were investigated by small trenches and electric resistivity measurements. Sediment thicknesses reach up to 2 m inside the caves and below the entrances. For one year nets were installed to measure rockfall in both caves. In warm periods generally less than 5 g/month of debris could be collected, but a few 100 g/month for frost periods. This strong correlation and the significant amount of debris together with other observations suggest that frost weathering is an on-going and very important process for the formation of these caves. Grain-size distribution of the collected debris argues for the activity of both microgelivation and ice segregation. Therefore we suggest that the term frost weathering caves should be used for shelter caves whose genesis is related to frost weathering. As dissolution seems to be of marginal importance for the genesis they are a paradox as they develop in karstic rock but have pseudokarst features.

Oberender, Pauline; Plan, Lukas

2015-01-01

45

Neural Network-Based Model for Landslide Susceptibility and Soil Longitudinal Profile Analyses : two case studies  

DEFF Research Database (Denmark)

The purpose of this study was to create an empirical model for assessing the landslide risk potential at Savadkouh Azad University, which is located in the rural surroundings of Savadkouh, about 5 km from the city of Pol-Sefid in northern Iran. The soil longitudinal profile of the city of Babol, located 25 km from the Caspian Sea, also was predicted with an artificial neural network (ANN). A multilayer perceptron neural network model was applied to the landslide area and was used to analyze specific elements in the study area that contributed to previous landsliding events. The ANN models were trained with geotechnical data obtained from an investigation of the study area. The quality of the modeling was improved further by the application of some controlling techniques involved in ANN. The observed >90% overall accuracy produced by the ANN technique in both cases is promising for future studies in landslide susceptibility zonation.

Farrokhzad, F.; Barari, Amin

2011-01-01

46

Susceptibility of polysiloxane and colloidal silica to degradation by soil microorganisms  

Energy Technology Data Exchange (ETDEWEB)

This report is a description of the laboratory study undertaken to determine the biodegradability of Colloidal Silica (CS) and PolySiloXane (PSX), a new generation of barrier liquids employed by the Viscous Liquid Barrier (VLB) technology in the containment of subsurface contaminants. Susceptibility of either material to microbial degradation would suggest that the effectiveness of a barrier in the subsurface may deteriorate over time. Degradation may result from several different biological events. Organisms may consume the material as a carbon and/or energy source, organisms may chemically change the material as a detoxification mechanism, or organisms may erode the material by their physical penetration of the material during growth. To determine if degradation occurs, physical interactions between soil microbes and the barrier materials were analyzed, and the metabolic activity of individual organisms in the presence of CS and PSX was measured.

Lundy, D.Z.; Hunter-Cevera, J.C.; Moridis, G.J. [Lawrence Berkeley National Lab., CA (United States). Earth Sciences Div.

1997-11-01

47

Mapping Statistical Characteristics of Frosts in Iran  

Science.gov (United States)

To model and map the statistical characteristics of frost in Iran, the data related to the minimum daily temperature for a 15-year period (1990-2005) was obtained from Iran Meteorological Organization. Then using multivariate regression models, the relationship among five statistical characteristics, i.e. the mean Julian day of the first frost, mean Julian day of the last frost, mean number of frost days per year, mean length of the frost period and mean length of growing season were modeled by three geo - climate factors: elevation, longitude and latitude. The precision of each model was explored using four hypotheses: linearity of the relationship between independent variables and the dependent variable, normality of errors, constancy of error variance and lake of correlation of errors were tested, and their precisions were confirmed. At the second stage, contour lines resulting from STRM were converted to the point features class. Altogether, 661 474 points were gathered from all over Iran. Then, the studied five frost characteristics were generalized to 661 474 points; then, the regionalization maps of statistical characteristics of frost were obtained for Iran using Kriging interpolation method. The results showed that the temperature of highland areas above 4200 m above sea level always was at least zero and below zero during the year, and also the coastal strip of southern Iran had no frost. Elevation was the most effective factor in the spatial arrangement for the frequency of occurrence of Julian day of the first frost. The most effective factors in spatial arrangement for the frequency of occurrence of Julian day of the last frost, length of frost period and length of growing season were elevation and latitude. Finally, spatial arrangement for the frequency of occurrence of the frost days was also a function of three factors of elevation, longitude and latitude. The dominant role of elevation in spatial arrangement for the occurrence of the first frost day in Iran showed that the occurrence of the first frost day in Iran could be of the type of radiation frosts and the dominant role of elevation and latitude demonstrated that late-winter frosts can be mostly of the type of advection frosts. Therefore, arrangement of statistical features of frost in Iran is both a function of geo - climate factors and the synoptic systems which have entered the country.

Mahmoudi, P.

2014-10-01

48

EVALUATION OF FROST HEAVE ON WASTE TRANSFER LINES WITH SHALLOW DEPTHS IN DST (DOUBLE SHELL TANK) FARMS  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this document is to evaluate the effect of frost heave on waste transfer lines with shallow depths in DST farms. Because of the insulation, well compacted sandy material around waste transfer lines, the type of sandy and gravel soil, and relatively low precipitation at Hanford site, it is concluded that waste transfer lines with one foot of soil covers (sandy cushion material and insulation) are not expected to undergo frost heave damaging effects.

HAQ MA

2009-05-12

49

Suscetibilidade de dois tipos de solo à compactação Compaction susceptibility of two classes of soil  

Directory of Open Access Journals (Sweden)

Full Text Available Com vistas ao aumento da produção agrícola, optou-se no Brasil, pelo acréscimo de área cultivada; para tal o uso indiscriminado da motomecanização mostrou-se eficiente em um primeiro momento, porém acarretando problemas à física do solo no decorrer dos anos. Paralelamente, práticas conservacionistas se fazem presentes, vide semeadura sob a palha (Plantio Direto, uma realidade no sul do Brasil. Sendo assim, avaliou-se a suscetibilidade de compactação de dois tipos de solo, ambos com sistema de semeadura sob a palha. Para dimensionar a suscetibilidade a compactação, utilizou-se ensaio de Proctor. Os solos foram ensaiados com e sem a presença de matéria orgânica livre. Os resultados demonstraram que para o Cambissolo, textura média, não houve diferença nos valores que representam a suscetibilidade, enquanto no Latossolo Vermelho, textura argilosa, não houve diferença entre a máxima densidade aparente, porém houve diferença significativa no conteúdo de água para a máxima densidade, o mesmo alterou-se de 0,249 g g-1 no ponto de máxima compactação no ensaio sem a presença de matéria orgânica livre, para 0,283 g g-1 no ponto de máxima compactação, quando da presença da matéria orgânica livre.For increasing agricultural production, Brazil opted to enlarge the cultivated area, and indiscriminate mechanization was efficient at the first moment, although it altered adversely the soil properties with the passage of time. At the same time, conservation practices, like the direct sowing under the straw (No Tillage were adopted which is a reality in Southern Brazil. Considering this, the susceptibility for compaction of two classes of soil was evaluated under no tillage system, with and without free organic matter. The Proctor test was used to measure the degree of compaction. The results of a medium texture Cambissol showed there was no difference in susceptibility for compaction. The clay textured Red Latossol, showed no difference in the maximum apparent density, although there was significant difference in water content at maximum density. The values altered from 0.249 g g-1, at a maximum compaction point without free organic matter to 0.283 g g-1 with free organic matter.

Pedro H. Weirich Neto

2002-01-01

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Improvement of frost tolerance in potato. Use of hydroxyproline reistant cell cultures.  

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This thesis describes investigations on a new method aimed at the development of a new method to produce potato plants less susceptible to frost. The essential part of this method was the selection of cells from cell cultures, followed by regeneration into intact plants. Zie: Summary and general conclusions

Swaaij, Arnoldus Carolus Petrus Maria

1986-01-01

51

Soil ecosystem health and services – Evaluation of ecological indicators susceptible to chemical stressors  

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The paper presents a methodological framework for quantifying soil ecosystem health with special focus on chemical stressors and ecological integrity as determinant for biological productivity of soil ecosystems. Ecological risk assessment is needed to facilitate the assessment of soil health and the capability of a soil to provide ecosystem services such as e.g. detoxification and decomposition of wastes, soil formation and renewal of soil fertility. We have developed such an approach that i...

Thomsen, M.; Faber, J. H.; Sorensen, P. B.

2012-01-01

52

Using magnetic susceptibility to assess soil degradation in the Eastern Rif, Morocco  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The soil in the Rif, Morocco, is at serious risk because increasing anthropogenic pressures are gradually transforming large natural areas into farmland. The distribution of magnetic minerals within the soil profile can be used to assess soil development and degradation. The soils in the study area are severely eroded because of a combination of highly erodible soils, intense rainstorms and scarce vegetation cover. To sample of representative soil profiles, lithology, slope gradient and land ...

Sadiki, Abdelhamid; Faleh, Ali; Navas Izquierdo, Ana; Bouhlassa, Saidati

2009-01-01

53

Evaluation of Cover Crops with Potential for Use in Anaerobic Soil Disinfestation (ASD) for Susceptibility to Three Species of Meloidogyne.  

Science.gov (United States)

Several cover crops with potential for use in tropical and subtropical regions were assessed for susceptibility to three common species of root-knot nematode, Meloidogyne arenaria, M. incognita, and M. javanica. Crops were selected based on potential use as organic amendments in anaerobic soil disinfestation (ASD) applications. Nematode juvenile (J2) numbers in soil and roots, egg production, and host plant root galling were evaluated on arugula (Eruca sativa, cv. Nemat), cowpea (Vigna unguiculata, cv. Iron & Clay), jack bean (Canavalia ensiformis, cv. Comum), two commercial mixtures of Indian mustard and white mustard (Brassica juncea & Sinapis alba, mixtures Caliente 61 and Caliente 99), pearl millet (Pennisetum glaucum, cv. Tifleaf III), sorghum-sudangrass hybrid (Sorghum bicolor × S. bicolor var. sudanense, cv. Sugar Grazer II), and three cultivars of sunflower (Helianthus annuus, cvs. 545A, Nusun 660CL, and Nusun 5672). Tomato (Solanum lycopersicum, cv. Rutgers) was included in all trials as a susceptible host to all three nematode species. The majority of cover crops tested were less susceptible than tomato to M. arenaria, with the exception of jack bean. Sunflower cv. Nusun 5672 had fewer M. arenaria J2 isolated from roots than the other sunflower cultivars, less galling than tomato, and fewer eggs than tomato and sunflower cv. 545A. Several cover crops did not support high populations of M. incognita in roots or exhibit significant galling, although high numbers of M. incognita J2 were isolated from the soil. Arugula, cowpea, and mustard mixture Caliente 99 did not support M. incognita in soil or roots. Jack bean and all three cultivars of sunflower were highly susceptible to M. javanica, and all sunflower cultivars had high numbers of eggs isolated from roots. Sunflower, jack bean, and both mustard mixtures exhibited significant galling in response to M. javanica. Arugula, cowpea, and sorghum-sudangrass consistently had low numbers of all three Meloidogyne species associated with roots and are good selections for use in ASD for root-knot nematode control. The remainder of crops tested had significant levels of galling, J2, and eggs associated with roots, which varied among the Meloidogyne species tested. PMID:24379486

Kokalis-Burelle, Nancy; Butler, David M; Rosskopf, Erin N

2013-12-01

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OECI TuBaFrost tumor biobanking.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

OECI TuBaFrost harbors a complete infrastructure for the exchange of frozen tumor samples between European countries. OECI TuBaFrost consists of: * A code of conduct on how to exchange human residual samples in Europe, * A central database application accessible over the Internet (www.tubafrost.org) where data can be uploaded and searched from samples that can be selected and ordered, * Access rules with incentives for collectors, * Standardization needed to enable the analysis of high qualit...

Riegman, Ph; Bosch, Al

2008-01-01

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AVALIAÇÃO DA SUSCEPTIBILIDADE DE SOLOS GNAISSICOS À EROSÃO SUBSUPERFICIAL / Evaluation of piping erosion susceptibility in gnaissic soils  

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Full Text Available The basement rock areas of the Maracujá hydrographic basin show great incidence of hugegullies. This work aims to investigate the influence of the underground erosive processes inthe evolution of these features and to understand how the mineralogical and textural factorscould affect soil erodibility, specially of the saprolites, since the lateric soils of this basin aremore resistant to erosion. So, basic characterization and erodibility essays were carried out in representative soil samples. Soil susceptibility to piping and seepage erosion were investigatedthrough current and modified pin-hole-essays. Laboratory physical models were used in orderto observe these and other possible underground erosion mechanisms, especially the slides.However, piping erosion only occurs in the unsaturated portion of gully slopes, provoked bythe concentration of superficial water, since pipes are not stable under total saturation, whentheir roofs tend to collapse, because of the low cohesion of these saprolites. In the other hand,slumps are very common in the saturated portion of gullies, affecting saprolites even in smalland low declivity slopes.

Frederico Garcia Sobreira

2007-12-01

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Frost Growth and Densification in Laminar Flow Over Flat Surfaces  

Science.gov (United States)

One-dimensional frost growth and densification in laminar flow over flat surfaces has been theoretically investigated. Improved representations of frost density and effective thermal conductivity applicable to a wide range of frost circumstances have been incorporated. The validity of the proposed model considering heat and mass diffusion in the frost layer is tested by a comparison of the predictions with data from various investigators for frost parameters including frost thickness, frost surface temperature, frost density and heat flux. The test conditions cover a range of wall temperature, air humidity ratio, air velocity, and air temperature, and the effect of these variables on the frost parameters has been exemplified. Satisfactory agreement is achieved between the model predictions and the various test data considered. The prevailing uncertainties concerning the role air velocity and air temperature on frost development have been elucidated. It is concluded that that for flat surfaces increases in air velocity have no appreciable effect on frost thickness but contribute to significant frost densification, while increase in air temperatures results in a slight increase the frost thickness and appreciable frost densification.

Kandula, Max

2011-01-01

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Identification of Soil Bacteria Susceptible to TiO2 and ZnO Nanoparticles  

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Because soil is expected to be a major sink for engineered nanoparticles (ENPs) released to the environment, the effects of ENPs on soil processes and the organisms that carry them out should be understood. DNA-based fingerprinting analyses have shown that ENPs alter soil bacterial communities, but specific taxon changes remain unknown. We used bar-coded pyrosequencing to explore the responses of diverse bacterial taxa to two widely used ENPs, nano-TiO2 and nano-ZnO, at various doses (0, 0.5,...

Ge, Yuan; Schimel, Joshua P.; Holden, Patricia A.

2012-01-01

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Rapid frost weathering and its potential role as a periglacial buzzsaw  

Science.gov (United States)

Icy Bay, in the Chugach-St.Elias mountains of southern Alaska, provides an excellent opportunity to 1) document exceptionally rapid breakdown of cobbles on surfaces recently exposed by glacial retreat, 2) examine frost-induced breakdown in light of recent advances in theory, and 3) explore the potential role of periglacial processes in limiting the height of mountain ranges. The latter adds to the current interest in the interactions between topography, tectonics and climate, and in particular, the so-called glacial buzzsaw (Egholm, et al. 2009. Nature, 460, p 884; doi:10.1038/nature08263). This is the notion that the growth of mountains is curtailed by erosion and related effects of glaciers with little or no dependence on the factors that are generally thought to control the height of mountains; height increases with the elevation of the snow line, with little or no influence of uplift and exhumation rates, rock type, and precipitation. A well-documented retreat of tidewater glaciers in Icy Bay has resulted in a succession of outwash surfaces on which cobbles of diverse lithology were exposed to atmospheric conditions sequentially. Following deposition, initial breakdown rates were determined for each of four distinct lithologies: siltstone, sandstone, greenschist, and granite/gneiss. These rates decrease to negligible values after 10-15 years of exposure. Breakdown is significantly enhanced adjacent to the current shoreline with the fraction of surface cobbles fractured after 30 years ranging from 20% for granite/gneiss to 90% for siltstone. Theoretical considerations suggest that the susceptibility of a rock type to frost weathering is dictated by its specific surface area and resistance to fracture. These parameters define a threshold zone for frost weathering specific to ambient thermal and moisture conditions in Icy Bay, a conclusion substantiated by independent experimental evidence. This result, coupled with the fact that this and other studies have shown enhanced rock breakdown under relatively mild climatic conditions, suggests the importance of unfrozen water migration in frost weathering under natural conditions and a significantly greater spatial importance of frost weathering than previously recognized. The rate of frost weathering should be maximized for temperatures between -3 to -10°C and in the presence of abundant moisture. These conditions ought to define an elevation interval in mountainous landscapes most conducive to frost weathering. Climatic fluctuations ought to drive large altitudinal changes in this interval causing variations in affected land area. Frost weathering appears to be significantly faster than other subaerial weathering mechanisms, and probably contributes significantly to the rapid exhumation documented in the Icy Bay region (Berger, A.L., et al. 2008. Nature Geoscience,1, 793-802.)

Hallet, Bernard; Roche, James

2010-05-01

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Avaliação da susceptibilidade de solos gnaissicos à erosão subsuperficial / Evaluation of piping erosion susceptibility in gnaissic soils  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese As áreas com rochas do embasamento cristalino da bacia do rio Maracujá apresentam grande incidência de voçorocas de grandes dimensões. O presente trabalho objetivou investigar a influência dos processos erosivos subsuperficiais na evolução destas formas de erosão, além de compreender quais os fatore [...] s mineralógicos e texturais que poderiam influenciar na erodibilidade dos solos da bacia, especialmente dos saprolitos. Para tanto, foram realizados ensaios de caracterização básica e de avaliação da erodibilidade em amostras representativas, sendo o principal destes o ensaio de pin-hole, que avalia a suscetibilidade dos solos à erosão por piping e, com modificações, também por erosão por carreamento. Foram construídos em laboratório modelos físicos a fim de se observar estes e outros possíveis mecanismos de erosão atuantes nos taludes das voçorocas, especialmente os escorregamentos. Os resultados mostram que as voçorocas da bacia não sofrem influência significativa dos pipings em seu avanço, tendo em vista que estes só ocorrem na parte não saturada dos taludes das voçorocas, quando são formados pela ação da concentração de águas superficiais. Isto se dá porque os saprolitos colapsam quando saturados em função de sua baixa coesão, fazendo com que os pipings não se preservem. Por outro lado, as experiências com modelagem física e os dados de campo evidenciam que os saprolitos, quando saturados, instabilizam-se por meio de escorregamentos rotacionais (slumps), mesmo em taludes baixos e pouco íngremes. Abstract in english The basement rock areas of the Maracujá hydrographic basin show great incidence of huge gullies. This work aims to investigate the influence of the underground erosive processes in the evolution of these features and to understand how the mineralogical and textural factors could affect soil erodibil [...] ity, specially of the saprolites, since the lateric soils of this basin are more resistant to erosion. So, basic characterization and erodibility essays were carried out in representative soil samples. Soil susceptibility to piping and seepage erosion were investigated through current and modified pin-hole-essays. Laboratory physical models were used in order to observe these and other possible underground erosion mechanisms, especially the slides. However, piping erosion only occurs in the unsaturated portion of gully slopes, provoked by the concentration of superficial water, since pipes are not stable under total saturation, when their roofs tend to collapse, because of the low cohesion of these saprolites. In the other hand, slumps are very common in the saturated portion of gullies, affecting saprolites even in small and low declivity slopes.

Fernando, Morais; Luis Almeida Prado, Bacellar; Frederico Garcia, Sobreira.

2007-12-01

60

Assessment of Liquefaction Susceptibility of Kutahya Soils Based on Recent Earthquakes in Turkey  

Science.gov (United States)

The plate tectonic setting of Turkey resulted many destructive earthquakes having magnitude higher than 7 in several cities situated close to faulting system. The city of Kutahya and its surrounding counties are notable examples to be located in the earthquake prone region and therefore, several earthquakes have been recently recorded particularly in its Simav district. A significant part of the residential area of Kutahya is found on alluvial deposits dominated by silt and fine sand size materials, and its southern boundary is controlled by Kutahya fault zone (KFZ) extending parallel to the city settlement. In this study, considering the possibility of a potential destructive earthquake in future as well as increasing population dependent further demand for new building in this city, investigation liquefaction potential of these soils is aimed for using in earthquake risk mitigation strategies. For this purpose, physical, ground water condition and standard penetration test (SPT) results from 283 different boreholes spreading over a wide area were examined to understand the behaviour this soil under earthquake induced dynamic loading. The total assessed drilling depth is about 2140 m. Required corrections were applied to all SPT data for obtaining SPT-(N1)60 values for liquefaction analyses. The estimation representative magnitude, depth of epicentre and maximum ground acceleration (amax) based on previous earthquakes and faulting characteristics of KFZ were initial targets for accurately assessment liquefaction phenomena of this city. For determination of amax in this region, in addition to attenuation relationship based on Turkish strong ground motion data, individual measurements from earthquakes stations closing to study site were also collected. As a result of all analyses and reviewing previous earthquakes records in this region, earthquake magnitudes vary between 5.0 and 7.4, and amax values changing between 400 and 800 gal were used in liquefaction analyses and in liquefaction hazard maps. Considering the variation physical properties, particularly relative density and grain size of soil with depth, these maps were prepared for the depth of 1.5 m, 3.0 m, 4.5 m, 6.0 m, 7.5 m and 9.0 m. In addition, three different maps were designed based on the concept of liquefaction index for M-amax data pairs of 6.5- 400 gal, 7.2-400 gal and 7.2-800 gal, respectively. It may be concluded that these maps can be used better tools for the general public as well as land-use planners to provide more secure and planned urbanization in the city of Kutahya.

Zengin, Enes; Abiddin Erguler, Zeynal

2014-05-01

 
 
 
 
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Nutritional Status and Susceptibility of Advanced Chickpea Germplasm to Low Soil Zinc and Boron  

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Full Text Available Shoot samples at preflowering stage and grains at maturity from four replicated field trials on advanced germplasm of chickpea along with some of the commercial varieties were collected. Three trials consisted of Desi germplasm with 12, 12, and 8 entries while the fourth one had 11 entries of Kabuli material. The advanced lines appeared to be highly promising as they gave maximum increase over the old check varieties in grain yield upto 60 percent in first trial followed by 58 percent in second, 53 percent in third and 43 percent in the 4th one. On the overall basis, the whole germplasm under study contained sufficient B and Cu, while Zn and P (in grain were marginal if not deficient. Almost all the material had relatively higher B in the grain than that of cereals like wheat. After field survey, a followup soil pot culture study was conducted employing 5 varieties and 2 lines on a soil with marginal Zn and B. Variety 6153 responded to 5 mg kg -1 Zn application by 39, CM 72 by 26, NIFA 95 by 17 and mutant CM 1571-1-A by 11 percent, while remaining responded negligibly. Mutant CM 31-1 responded to 1 mg kg -1 B application by 30, CM 1571-1-A, C 44 and 6153 shared the response by 27 percent. Remaining three did not respond or responded negatively. All the entries in the four trials contained marginal Zn i.e.,<20 mg kg-1 and sufficient B i.e., >30 mg kg-1, yet some of them responded to the applications markedly indicating their high B and Zn requirement than reported in the literature.

M.A.Kausar

2000-01-01

62

Ecophysiological study of frost hardening in trees.  

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The impact of the contrasted summer conditions of growth (defoliation, drought, nitrogen deficiency, ...) on the freezing tolerance of different tissues and organs, in relation to their carbohydrate status, is studied in walnut trees (Juglans regia). Comparison of several methods for estimate the freezing tolerance (electrolyte leakage test, GélistaTM method, optical microscopy, whole plant freeze test) showed that GélistaTM method, a new tool for testing frost hardiness by stem diameter va...

Poirier, Magali

2008-01-01

63

An improved model for predicting performance of finned tube heat exchanger under frosting condition, with frost thickness variation along fin  

Energy Technology Data Exchange (ETDEWEB)

Frost accumulation on a heat exchanger, a direct result of combined heat and mass transfer between the moist air flowing across a cold surface, causes heat transfer performance degradation due to the insulating effect of frost layer and the coil blockage as the frost grows. The complex geometry of finned tube heat exchangers leads to uneven wall and air temperature distribution inside the coil, and causes variations of frost growth rate and densification along the coil. In this study, a general distributed model with frost formation was developed. The equations for finned tube heat exchanger were derived in non-steady-state manner and quasi-steady state in the frost model. In order to make the model more realistic, the variation of frost along fin due to uneven temperature distribution was included. The presented model is able to predict the dynamic behavior of an air cooler both under non-frost and frost condition. Comparisons were made based on the frost mass accumulation, pressure drop across coil and energy transfer coefficient, and results were found to agree well with reported experimental results. (author)

Tso, C.P. [Multimedia University, Jalan Ayer Keroh Lama, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore (Singapore). School of Mechanical and Aerospace Engineering

2006-01-15

64

Gamma-ray spectrometry, electrical resistivity, and magnetic susceptibility of agricultural soils in the Northwest region of the Parana State, Brazil  

International Nuclear Information System (INIS)

Gamma-ray spectrometry, electrical resistivity, and magnetic susceptibility measurements were taken from agricultural areas near the City of Maringa, in the Northwest region of the Parana state, south Brazil, in order to characterize the spatial distribution of radionuclides (K, eU, and eTh), the apparent resistivity, and the magnetic susceptibility determined for soils. Three different types of soils are present in this agricultural area: Alfisoil, clayey texture Oxisoil, both deriving from Lower Cretaceous basalts of the Serra Geral Formation; and medium texture Oxisoil from reworked Serra Geral and Goio-Ere formations, the latter deriving from sandstones of the Upper Cretaceous Caiua Group. It could be observed that in more clayey soils both concentration of radionuclides and susceptibility values are higher than in more sandy soils, especially due to the higher adsorption in the former and to the higher availability of magnetic minerals in the latter. The average ppm and Bq Kg-1 grades for K, eU, and eTh in the areas under anthropic activity are of 1766-54.75, 0.83-10.22, and 1.78-7.27, respectively. These grades are significantly higher than those of non-occupied or non-fertilized areas (1101-34.15 K, 0.14-1.69 eU, and 1.31-5.36 eTh in ppm and Bq Kg-1, respectively.) Correlations were observed between uranium and clay, uranium and magnetic susceptibility, uranium and organic matter, and between electric resistivity and clay grades. Varied concentrationvity and clay grades. Varied concentrations of radionuclides were also observed in different fertilizer formulations applied to soy and wheat cultures. Apparent electric resistivity values between 25 and 647 Ohm.m and magnetic susceptibility values between 0.28 e 1.10 x 10-3 SI due to clay and magnetic minerals represented important soil discrimination factors in the study area that can be incorporated as easy, low-cost soil mapping tools. (author)

65

Frost Formation and Defrosting for Heat Pump Systems  

Science.gov (United States)

Recently, frost formation becomes an more important phenomenon not only in the cryogenic equipment but also in the air conditioner equipped with heat pump systems. When heat pump systems are used to supply thermal energy from air for the purpose of space heating in winter, the surface temperature of the evaporator often falls below 0°C and then frost deposition occurs there because it gains heat from the cold outdoor air. Frost formation cannot be treated easily as a growth of uniform substances such as ice because of the complicated nature of a frost layer. Accordingly, frost formation has been studied from the various points of view. This paper will give a review of studies on frost fomation and defrosting connected with heat pump systems.

Aoki, Kazuo

66

Suitability aero-geophysical methods for generating conceptual soil maps and their use in the modeling of process-related susceptibility maps  

Science.gov (United States)

In the past years, several times large-scale disasters occurred in Austria, which were characterized not only by flooding, but also by numerous shallow landslides and debris flows. Therefore, for the purpose of risk prevention, national and regional authorities also require more objective and realistic maps with information about spatially variable susceptibility of the geosphere for hazard-relevant gravitational mass movements. There are many and various proven methods and models (e.g. neural networks, logistic regression, heuristic methods) available to create such process-related (e.g. flat gravitational mass movements in soil) suszeptibility maps. But numerous national and international studies show a dependence of the suitability of a method on the quality of process data and parameter maps (f.e. Tilch & Schwarz 2011, Schwarz & Tilch 2011). In this case, it is important that also maps with detailed and process-oriented information on the process-relevant geosphere will be considered. One major disadvantage is that only occasionally area-wide process-relevant information exists. Similarly, in Austria often only soil maps for treeless areas are available. However, in almost all previous studies, randomly existing geological and geotechnical maps were used, which often have been specially adapted to the issues and objectives. This is one reason why very often conceptual soil maps must be derived from geological maps with only hard rock information, which often have a rather low quality. Based on these maps, for example, adjacent areas of different geological composition and process-relevant physical properties are razor sharp delineated, which in nature appears quite rarly. In order to obtain more realistic information about the spatial variability of the process-relevant geosphere (soil cover) and its physical properties, aerogeophysical measurements (electromagnetic, radiometric), carried out by helicopter, from different regions of Austria were interpreted. Previous studies show that, especially with radiometric measurements, the two-dimensional spatial variability of the nature of the process-relevant soil, close to the surface can be determined. In addition, the electromagnetic measurements are more important to obtain three-dimensional information of the deeper geological conditions and to improve the area-specific geological knowledge and understanding. The validation of these measurements is done with terrestrial geoelectrical measurements. So both aspects, radiometric and electromagnetic measurements, are important and subsequently, interpretation of the geophysical results can be used as the parameter maps in the modeling of more realistic susceptibility maps with respect to various processes. Within this presentation, results of geophysical measurements, the outcome and the derived parameter maps, as well as first process-oriented susceptibility maps in terms of gravitational soil mass movements will be presented. As an example results which were obtained with a heuristic method in an area in Vorarlberg (Western Austria) will be shown. References: Schwarz, L. & Tilch, N. (2011): Why are good process data so important for the modelling of landslide susceptibility maps?- EGU-Postersession "Landslide hazard and risk assessment, and landslide management" (NH 3.6), Vienna. [http://www.geologie.ac.at/fileadmin/user_upload/dokumente/pdf/poster/poster_2011_egu_schwarz_tilch_1.pdf] Tilch, N. & Schwarz, L. (2011): Spatial and scale-dependent variability in data quality and their influence on susceptibility maps for gravitational mass movements in soil, modelled by heuristic method.- EGU-Postersession "Landslide hazard and risk assessment, and landslide management" (NH 3.6); Vienna. [http://www.geologie.ac.at/fileadmin/user_upload/dokumente/pdf/poster/poster_2011_egu_tilch_schwarz.pdf

Tilch, Nils; Römer, Alexander; Jochum, Birgit; Schattauer, Ingrid

2014-05-01

67

Winter frost resistance of Pinus cembra measured in situ at the alpine timberline as affected by temperature conditions.  

Science.gov (United States)

Winter frost resistance (WFR), midwinter frost hardening and frost dehardening potential of Pinus cembra L. were determined in situ by means of a novel low-temperature freezing system at the alpine timberline ecotone (1950 m a.s.l., Mt Patscherkofel, Innsbruck, Austria). In situ liquid nitrogen (LN?)-quenching experiments should check whether maximum WFR of P. cembra belonging to the frost hardiest conifer group, being classified in US Department of Agriculture climatic zone 1, suffices to survive dipping into LN? (-196 °C). Viability was assessed in a field re-growth test. Maximum in situ WFR (LT??) of leaves was water contents. In midwinter, in situ freezing exotherms of leaves, buds and the xylem were often not detectable. Ice formed in the xylem at a mean of -2.8 °C and in leaves at -3.3 °C. In situ WFR of P. cembra was higher than that obtained on detached twigs, as reported earlier. In situ LN?-quenching experiments were lethal in all cases even when twigs of P. cembra were exposed to an in situ frost hardening treatment (12 days at -20 °C followed by 3 days at -50 °C) to induce maximum WFR. Temperature treatments applied in the field significantly affected the actual WFR. In January a frost hardening treatment (21 days at -20 °C) led to a significant increase of WFR (buds: -62 °C to <-?70 °C; leaves: -59.6 °C to -65.2 °C), showing that P. cembra was not at its specific maximum WFR. In contrast, simulated warm spells in late winter led to premature frost dehardening (buds: -32.6 °C to -10.2 °C; leaves: -32.7 to -16.4 °C) followed by significantly earlier bud swelling and burst in late winter. Strikingly, both temperature treatments, either increased air temperature (+10.1 °C) or increased soil temperature (+6.5 °C), were similarly effective. This high readiness to frost harden and deharden in winter in the field must be considered to be of great significance for future winter survival of P. cembra. Determination of WFR in field re-growth tests appears to be a valuable tool for critically judging estimates of WFR obtained on detached twigs in an ecological context. PMID:22011966

Buchner, Othmar; Neuner, Gilbert

2011-11-01

68

Identificación de suelos susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua / Identification of soils susceptible to risk erosion and with hight capacity of water storage  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish La investigación se basó en el desarrollo de siete etapas metodológicas con criterios de integralidad, análisis holístico, secuencia lógica, participación y sencillez, destacándose los siguientes aspectos: Conceptualización y contextualización, muestreo de suelos, procesamiento de la información, es [...] pacialización de la información, identificación de zonas susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua, recomendaciones de manejo y socialización de la investigación. La propuesta metodológica se validó y ajustó mediante un caso de estudio en la vereda Chicoral, subcuenca del río Bitaco, municipio de La Cumbre, Valle del Cauca, Colombia. Mediante procesos de participación y concertación con los actores socioeconómicos del área de estudio se lograron diagnosticar las causas y consecuencias que intervienen en procesos de degradación física del suelo y a la vez se localizaron los sitios con mayor potencialidad de almacenamiento de agua, factores importantes para la planificación y uso racional de los recursos naturales en una cuenca hidrográfica. Abstract in english The investigation was carried out in seven methodological steps under integral approaches, holistic analysis, logical sequence, participation and simplicity. The following aspects were highlighted: Conceptualization and contextualizacion, soil sampling , data processing, data spacializatión of the i [...] nformation, identification of susceptible areas to risk erosion with higher capacity of water storage, management norms and socialization of the investigation. The methodological proposal was validated and adjusted by a case of study in the rural areas of Chicoral, watershed of the Bitaco river, Municipality of La Cumbre, Cauca Valley, Colombia. Using participation processes and agreement with the communities of the study area, the diagnostic of the causes and consequences that intervene in processes of physical soil degradation were reached. At the same time, the places with higher potentiality of water storage were localized. All of these factors are important for planning and rational use of the natural resources in a watershed.

Velásquez Valencia, Henry; Juan Carlos, Menjivar; Carlos Alberto, Escobar.

2007-09-15

69

Identification of soils susceptible to risk erosion and with hight capacity of water storage Identificación de suelos susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua  

Directory of Open Access Journals (Sweden)

Full Text Available The investigation was carried out in seven methodological steps under integral approaches, holistic analysis, logical sequence, participation and simplicity. The following aspects were highlighted: Conceptualization and contextualizacion, soil sampling , data processing, data spacializatión of the information, identification of susceptible areas to risk erosion with higher capacity of water storage, management norms and socialization of the investigation. The methodological proposal was validated and adjusted by a case of study in the rural areas of Chicoral, watershed of the Bitaco river, Municipality of La Cumbre, Cauca Valley , Colombia. Using participation processes and agreement with the communities of the study area, the diagnostic of the causes and consequences that intervene in processes of physical soil degradation were reached. At the same time, the places with higher potentiality of water storage were localized. All of these factors are important for planning and rational use of the natural resources in a watershed.La investigación se basó en el desarrollo de siete etapas metodológicas con criterios de integralidad, análisis holístico, secuencia lógica, participación y sencillez, destacándose los siguientes aspectos: Conceptualización y contextualización, muestreo de suelos, procesamiento de la información, espacialización de la información, identificación de zonas susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua, recomendaciones de manejo y socialización de la investigación. La propuesta metodológica se validó y ajustó mediante un caso de estudio en la vereda Chicoral, subcuenca del río Bitaco, municipio de La Cumbre, Valle del Cauca, Colombia. Mediante procesos de participación y concertación con los actores socioeconómicos del área de estudio se lograron diagnosticar las causas y consecuencias que intervienen en procesos de degradación física del suelo y a la vez se localizaron los sitios con mayor potencialidad de almacenamiento de agua, factores importantes para la planificación y uso racional de los recursos naturales en una cuenca hidrográfica.

Escobar Chalarca Carlos Alberto

2007-09-01

70

Identificación de suelos susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua Identification of soils susceptible to risk erosion and with hight capacity of water storage  

Directory of Open Access Journals (Sweden)

Full Text Available La investigación se basó en el desarrollo de siete etapas metodológicas con criterios de integralidad, análisis holístico, secuencia lógica, participación y sencillez, destacándose los siguientes aspectos: Conceptualización y contextualización, muestreo de suelos, procesamiento de la información, espacialización de la información, identificación de zonas susceptibles a riesgos de erosión y con mayor capacidad de almacenamiento de agua, recomendaciones de manejo y socialización de la investigación. La propuesta metodológica se validó y ajustó mediante un caso de estudio en la vereda Chicoral, subcuenca del río Bitaco, municipio de La Cumbre, Valle del Cauca, Colombia. Mediante procesos de participación y concertación con los actores socioeconómicos del área de estudio se lograron diagnosticar las causas y consecuencias que intervienen en procesos de degradación física del suelo y a la vez se localizaron los sitios con mayor potencialidad de almacenamiento de agua, factores importantes para la planificación y uso racional de los recursos naturales en una cuenca hidrográfica.The investigation was carried out in seven methodological steps under integral approaches, holistic analysis, logical sequence, participation and simplicity. The following aspects were highlighted: Conceptualization and contextualizacion, soil sampling , data processing, data spacializatión of the information, identification of susceptible areas to risk erosion with higher capacity of water storage, management norms and socialization of the investigation. The methodological proposal was validated and adjusted by a case of study in the rural areas of Chicoral, watershed of the Bitaco river, Municipality of La Cumbre, Cauca Valley, Colombia. Using participation processes and agreement with the communities of the study area, the diagnostic of the causes and consequences that intervene in processes of physical soil degradation were reached. At the same time, the places with higher potentiality of water storage were localized. All of these factors are important for planning and rational use of the natural resources in a watershed.

Velásquez Valencia Henry

71

Evaluation of host susceptibility, pathogen aggressiveness and sporangial survival in soil as factors affecting incidence of potato tuber infection by Phytophthora infestans in Ecuador  

Directory of Open Access Journals (Sweden)

Full Text Available Incidence of potato tuber infection by Phytophthora infestans is low in Ecuador. Factors considered to potentially affect the incidence of tuber infection include pathogen aggressiveness, host resistance, direct suppression from biological and chemical characteristics of soil acting on pathogen propagules, and exclusion resulting from soil structure and high ridging. In this study, we tested the hypothesis that low incidence could be due to reduced pathogen aggressiveness and/or low host susceptibility by comparing several pathogen isolates and commonly grown potato cultivars from Ecuador with isolates and cultivars from Europe, where tuber blight is known to be a problem. Additionally, in Ecuador, whole tubers and slices of common varieties were inoculated with local isolates of P. infestans to test for potential infection under Ecuadorian conditions. All isolates, regardless of origin, caused tuber infection. The aggressiveness of isolates varied, but this was both between and among Ecuadorian and Swedish isolates and it was not possible to establish a clear difference in the degree of infection based on isolate origin, or origin of potato variety. In general, we found no evidence to suggest that low aggressiveness of the pathogen or extreme resistance of the host explains low incidence of tuber blight in Ecuador. Therefore, we conclude that low incidence of tuber blight in Ecuador is probably caused by soil factors. Furthermore, exclusion due to soil structure and high hilling may play an important role as a preliminary soil infectivity study demonstrated that P. infestans sporangia were infective in six Ecuadorian field soils for at least 15 days.

Pedro J. Oyarzún

2011-06-01

72

Evaluation of host susceptibility, pathogen aggressiveness and sporangial survival in soil as factors affecting incidence of potato tuber infection by Phytophthora infestans in Ecuador  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Incidence of potato tuber infection by Phytophthora infestans is low in Ecuador. Factors considered to potentially affect the incidence of tuber infection include pathogen aggressiveness, host resistance, direct suppression from biological and chemical characteristics of soil acting on pathogen prop [...] agules, and exclusion resulting from soil structure and high ridging. In this study, we tested the hypothesis that low incidence could be due to reduced pathogen aggressiveness and/or low host susceptibility by comparing several pathogen isolates and commonly grown potato cultivars from Ecuador with isolates and cultivars from Europe, where tuber blight is known to be a problem. Additionally, in Ecuador, whole tubers and slices of common varieties were inoculated with local isolates of P. infestans to test for potential infection under Ecuadorian conditions. All isolates, regardless of origin, caused tuber infection. The aggressiveness of isolates varied, but this was both between and among Ecuadorian and Swedish isolates and it was not possible to establish a clear difference in the degree of infection based on isolate origin, or origin of potato variety. In general, we found no evidence to suggest that low aggressiveness of the pathogen or extreme resistance of the host explains low incidence of tuber blight in Ecuador. Therefore, we conclude that low incidence of tuber blight in Ecuador is probably caused by soil factors. Furthermore, exclusion due to soil structure and high hilling may play an important role as a preliminary soil infectivity study demonstrated that P. infestans sporangia were infective in six Ecuadorian field soils for at least 15 days.

Pedro J., Oyarzún; Anna-Karin, Krijger; Carla D., Garzón; Diego, Leon; Peter, Kromann; Jonathan E., Yuen; Gregory A., Forbes.

2011-06-01

73

Prediction of Frost Risks and Plagues using WRF model: a Port Wine region case study  

Science.gov (United States)

In viticulture where the quality of the wine, the selection of the grapevines or even the characteristics of the farming soil, also depending from local soil features like topography, proximity of a river or water body, will act locally on the weather. Frosts are of significant concern to growers of many cultures crops such as winegrapes. Because of their high latitude and some altitude, the vineyards of the Demarcated Douro Region (DDR) are subjected to the frost, which cause serious damages. But the hazards of vineyard don't confine to the incidents of the fortuitous and meteorological character. The illnesses and plagues affect frequently the vineyards of Demarcated Douro Region due, namely to the weather, to the high power of the regional stocks, to the dense vegetation badly drained and favourable to the setting of numberless fungi, viruses and/or poisonous insects. In the case of DDR it is worth noticing the meteorological conditions due to the weather characteristics. Although there are several illnesses and plagues the most important enemies for the vine in the DDR are the mildew, oidium, grey rottenness, grape moth,. . . , if the climatic conditions favour their appearance and development. For this study, we selected some months for different periods, at the 16 weather stations of the Region of Douro. We use the Weather Research and Forecast Model (WRF) to study and possibly predict the occurrence of risk and plagues (mildew) episodes. The model is first validated with the meteorological data obtained at the weather stations. The knowledge of frost and plagues occurrence allows one to decrease its risks not only by selecting the cultural species and varieties but also the places of growth and the planting and sowing dates.

Rodrigues, M. A.; Rocha, A.; Monteiro, A.; Quénol, H.; de Freitas, J. R.

2012-04-01

74

Landslide susceptibility assessment in ash-fall pyroclastic deposits surrounding Mount Somma-Vesuvius: Application of geophysical surveys for soil thickness mapping  

Science.gov (United States)

Along the steep slopes of the carbonate mountains that surround the Campanian Plain and Mount Somma-Vesuvius, rainfall-triggered debris slides occur in unconsolidated ash-fall pyroclastic deposits. The initial debris slides evolve into debris flows that often cause significant property damage and loss of human life in the towns located at the foot of the slopes. In this particular geological situation, the pyroclastic soil thickness, the slope angle, and the morphological variations of the slope profile are the most important factors that contribute to landslide susceptibility. In this paper, the results of an experimental application of shallow resistivity and refraction seismic soundings in mapping the thickness of pyroclastic soils are presented. These geophysical methods are proposed as low-cost and versatile methods to be used in the difficult morphological conditions of the steep slopes in which debris-slides initiate. The methods have been used experimentally in a sample area located on the upper slope of Mount Pizzo d'Alvano, from which debris flows initiated that dramatically hit the town of Sarno on 5-6 May 1998. The inversion of geoelectrical soundings has been calibrated with resistivity values measured directly on pyroclastic outcrops and with soil thickness estimations derived from refraction seismic soundings and from the application of a mobile dynamic penetrometer. The results of the field experimentation can be summarised as follows: (i) unconsolidated ash-fall pyroclastic deposits, ranging in particle size from fine ash to lapilli, can be differentiated from fractured carbonate bedrock by means of electrical resistivity and velocity values of longitudinal seismic waves; (ii) thickness of ash-fall pyroclastic soils can be empirically related to the slope angle using an inverse relationship; and (iii) the empirical model has been applied to Digital Elevation Model data, allowing pyroclastic soil thickness mapping in the sample area.

De Vita, P.; Agrello, D.; Ambrosino, F.

2006-06-01

75

Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces  

Energy Technology Data Exchange (ETDEWEB)

Self-propelled jumping drops are continuously removed from a condensing superhydrophobic surface to enable a micrometric steady-state drop size. Here, we report that subcooled condensate on a chilled superhydrophobic surface are able to repeatedly jump off the surface before heterogeneous ice nucleation occurs. Frost still forms on the superhydrophobic surface due to ice nucleation at neighboring edge defects, which eventually spreads over the entire surface via an inter-drop frost wave. The growth of this inter-drop frost front is shown to be up to three times slower on the superhydrophobic surface compared to a control hydrophobic surface, due to the jumping-drop effect dynamically minimizing the average drop size and surface coverage of the condensate. A simple scaling model is developed to relate the success and speed of inter-drop ice bridging to the drop size distribution. While other reports of condensation frosting on superhydrophobic surfaces have focused exclusively on liquid-solid ice nucleation for isolated drops, these findings reveal that the growth of frost is an inter-drop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser was found to be superior to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by minimizing the success of interdrop ice bridge formation.

Boreyko, Jonathan B [ORNL; Collier, Pat [ORNL

2013-01-01

76

Frost-related dieback of Swedish and Estonian Salix plantations due to pathogenic and ice nucleation-active bacteria  

Energy Technology Data Exchange (ETDEWEB)

During the past decade, important dieback has been observed in short-rotation forestry plantations of Salix viminalis and S. dasyclados in Sweden and Estonia, plantations from which the isolation of ice nucleation-active (INA) and pathogenic bacteria has also been reported. This thesis investigates the connection between bacterial infection and frost as a possible cause for such damage, and the role played by internal and external factors (e.g. plant frost sensitivity, fertilisation) in the dieback observed. Bacterial floras isolated from ten Salix clones growing on fertilised/unfertilised mineral soil or nitrogen-rich organic soil, were studied. Culturable bacterial communities present both in internal necrotic tissues and on the plant surface (i.e. epiphytes) were isolated on two occasions (spring and autumn). The strains were biochemically characterised (with gram, oxidase and fluorescence tests), and tested for ice nucleation-activity. Their pathogenic properties were studied with and without association to a freezing stress. Certain strains were eventually identified with BIOLOG plates and 16S rRNA analysis. A high number of culturable bacterial strains was found in the plant samplings, belonging mainly to Erwinia and Sphingomonas spp.; pathogenic and INA communities being mostly Erwinia-, Sphingomonas- and Xanthomonas-like. The generally higher plant dieback noted in the field on nutrient-rich soils and for frost sensitive clones was found connected to higher numbers of pathogenic and INA bacteria in the plants. We thus confirm Salix dieback to be related to a synergistic effect of frost and bacterial infection, possibly aggravated by fertilisation.

Cambours, M.A.

2004-07-01

77

Susceptibilidad del suelo a la degradación en parcelas con manejo agroforestal Quesungual en Nicaragua / Susceptibility to soil degradation in plots under Quesungual agroforestry management in Nicaragua  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Durante tres años se establecieron en un Andisol del municipio de Somotillo (Nicaragua) los sistemas de usos de tierra: tradicional del productor (tala, quema, fertilización y siembra de maíz + fríjol); agroforestal Quesungual (SAQ) (no quema, árboles nativos en regeneración natural y siembra de maí [...] z + fríjol); residuos de cultivos (manejo de cobertura con residuos de cultivos); y testigo bosque secundario (tacotal) de aproximadamente cinco años de edad no cultivado. Se hicieron muestreos de suelos a profundidades de 0-5, 5-10 y 10-20 cm para caracterización física y de fertilidad y estimación de la erosión hídrica por simulación. Los sistemas Quesungal y Residuos de Cultivo, mantuvieron la susceptibilidad del suelo a la erosión en niveles tan bajos como los del bosque natural secundario. Abstract in english In an andisol tt was placed for three years land uses systems like: farmer traditional (slash and burn, fertilization and sowing of bean and maiz); Quesungual Agroforestry System-SAQ (no burn, natural regeneration of native trees, bean and maiz sowing); crop residues as management cover, and a fi ve [...] years secundary forest (tacotal) as a control. It was considered soil samples at 0-5, 5-10 y 10-20 for physical and fertility characterization and field measurement of soil erosion by rain simulation. Quesungal and crop residues systems, remained soil erosión susceptibility at levels as low as the natural secondary forest.

Jellín del Carmen, Pavón T; Edgar, Madero M; Edgar, Amézquita C.

2010-01-01

78

Susceptibilidad del suelo a la degradación en parcelas con manejo agroforestal Quesungual en Nicaragua Susceptibility to soil degradation in plots under Quesungual agroforestry management in Nicaragua  

Directory of Open Access Journals (Sweden)

Full Text Available Durante tres años se establecieron en un Andisol del municipio de Somotillo (Nicaragua los sistemas de usos de tierra: tradicional del productor (tala, quema, fertilización y siembra de maíz + fríjol; agroforestal Quesungual (SAQ (no quema, árboles nativos en regeneración natural y siembra de maíz + fríjol; residuos de cultivos (manejo de cobertura con residuos de cultivos; y testigo bosque secundario (tacotal de aproximadamente cinco años de edad no cultivado. Se hicieron muestreos de suelos a profundidades de 0-5, 5-10 y 10-20 cm para caracterización física y de fertilidad y estimación de la erosión hídrica por simulación. Los sistemas Quesungal y Residuos de Cultivo, mantuvieron la susceptibilidad del suelo a la erosión en niveles tan bajos como los del bosque natural secundario.In an andisol tt was placed for three years land uses systems like: farmer traditional (slash and burn, fertilization and sowing of bean and maiz; Quesungual Agroforestry System-SAQ (no burn, natural regeneration of native trees, bean and maiz sowing; crop residues as management cover, and a fi ve years secundary forest (tacotal as a control. It was considered soil samples at 0-5, 5-10 y 10-20 for physical and fertility characterization and field measurement of soil erosion by rain simulation. Quesungal and crop residues systems, remained soil erosión susceptibility at levels as low as the natural secondary forest.

Jellín del Carmen Pavón T

2010-01-01

79

Modelos de paisagem e susceptibilidade magnética na identificação e caracterização do solo / Landscape models and magnetic susceptibility on soil identification and characterization  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O conhecimento detalhado do solo e de seus atributos, ao longo da paisagem, é uma demanda permanente dos sistemas urbanos e agroindustriais, para o planejamento sustentável de uso e ocupação. O presente trabalho objetivou estudar o potencial de modelos de paisagem e susceptibilidade magnética na ide [...] ntificação e caracterização de latossolos, em Guariba (SP). Foram coletadas 514 amostras de solo, em 110,0 ha, às profundidades de 0,0-0,20 m e 0,60-0,80 m. Foram identificados diferentes compartimentos de paisagem, com base no modelo de superfície geomórfica e segmento de vertente. Em cada compartimento de paisagem, foram abertas trincheiras, para classificação do solo. As amostras foram analisadas quanto à granulometria e atributos químicos, pH (água, CaCl2 e KCl), matéria orgânica, P extraível, K+, Ca2+, Mg2+ e H+ + Al3+. Também foram determinados os teores de SiO2, Al2O3, Fe2O3 e óxidos de Fe livres (Fe d) e pouco cristalizados (Fe o), nas amostras das trincheiras, além da susceptibilidade magnética (SM). Solos taxonomicamente iguais, porém em diferentes compartimentos da paisagem, apresentaram valores distintos, para os atributos estudados, indicando que os modelos de paisagem e a susceptibilidade magnética podem ser viáveis, como técnica de campo, para auxiliar no detalhamento da variação dos atributos do solo. A susceptibilidade magnética demonstrou ter potencial para delimitação das superfícies geomórficas mapeadas no campo, o que indica o seu potencial de uso, na identificação e caracterização de áreas mais homogêneas. Abstract in english The detailed knowledge of soils and their attributes, across the landscape, is a permanent demand of urban and agro-industrial systems, for planning their sustainable use and occupation. This study aimed at evaluating the potential of landscape models and the magnetic susceptibility in the identific [...] ation and characterization of oxisols, in Guariba, São Paulo State, Brazil. A total of 514 soil samples were collected in 110.0 ha, at the depths of 0.0-0.20 m and 0.60-0.80 m. Different landscape compartments, based on the geomorphic surface and segment slope models, were identified. In each landscape compartment, trenches were opened for soil classification. The samples were analyzed for particle size and chemical properties, pH (water, CaCl2 and KCl), organic matter, extractable P, K+, Ca2+, Mg2+ and H+ + Al3+. The contents of SiO2, Al2O3, Fe2O3 and free (Fe d) and slightly crystallized (Fe o) Fe oxides were determined in samples from the trenches, as well as the magnetic susceptibility (MS). Taxonomically similar soils, but in different landscape compartments, presented different values for the attributes studied, indicating that the landscape models and magnetic susceptibility may be viable, as a field technique, to help detailing the variation of soil attributes. The magnetic susceptibility showed potential for delimiting geomorphic surfaces mapped in the field, emphasizing its potential use for identifying and characterizing homogeneous areas.

Sammy Sidney Rocha, Matias; José, Marques Júnior; Diego Silva, Siqueira; Gener Tadeu, Pereira.

2013-03-01

80

24 CFR 3285.404 - Severe climatic conditions.  

Science.gov (United States)

...3285.404 Severe climatic conditions. In frost-susceptible soil locations, ground anchor augers must be installed below the frost line, unless the foundation system is frost-protected to prevent the effects of...

2010-04-01

 
 
 
 
81

On the Effective Thermal Conductivity of Frost Considering Mass Diffusion and Eddy Convection  

Science.gov (United States)

A physical model for the effective thermal conductivity of water frost is proposed for application to the full range of frost density. The proposed model builds on the Zehner-Schlunder one-dimensional formulation for porous media appropriate for solid-to-fluid thermal conductivity ratios less than about 1000. By superposing the effects of mass diffusion and eddy convection on stagnant conduction in the fluid, the total effective thermal conductivity of frost is shown to be satisfactorily described. It is shown that the effects of vapor diffusion and eddy convection on the frost conductivity are of the same order. The results also point out that idealization of the frost structure by cylindrical inclusions offers a better representation of the effective conductivity of frost as compared to spherical inclusions. Satisfactory agreement between the theory and the measurements for the effective thermal conductivity of frost is demonstrated for a wide range of frost density and frost temperature.

Kandula, Max

2010-01-01

82

Frost Multidimensional Perfectionism Scale: the portuguese version / Frost Multidimensional Perfectionism Scale: versão portuguesa  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese CONTEXTO: A Escala Multidimensional de Perfeccionismo de Frost (FMPS) é uma das escalas mais usadas em todo o mundo para avaliar o perfeccionismo. OBJETIVO: Analisar as características psicométricas da versão portuguesa da FMPS. MÉTODOS: A amostra foi constituída por 217 estudantes do ensino superio [...] r (178 mulheres). Um subgrupo (n = 166) completou o reteste após quatro semanas. RESULTADOS: A consistência interna da escala mostrou ser elevada (alfa de Cronbach = ,857). As correlações item-total corrigido variaram entre ,019 e ,548. Os resultados também sugeriram uma boa estabilidade temporal da escala, sendo a correlação teste-reteste de ,765. Foi realizada a análise das componentes principais com rotação Varimax e com base no Scree plot foram extraídas duas soluções fatoriais robustas (quatro e seis fatores). A análise paralela (Monte Carlo PCA) confirmou a solução de seis fatores. A validade concorrente com a escala MPS de Hewitt e Flett foi elevada, assim como a sua capacidade discriminante dos afetos positivos e negativos (Perfil de Estados de Humor - POMS). CONCLUSÃO: As duas estruturas fatoriais (quatro e seis fatores) encontradas na versão portuguesa da Escala Multidimensional de Perfeccionismo de Frost replicam os resultados obtidos por diferentes autores, em diferentes amostras e culturas. Esse fato sugere que essa escala é um instrumento robusto para a avaliação do perfeccionismo em vários contextos, clínicos e de investigação, bem como em estudos transculturais. Abstract in english BACKGROUND: The Frost Multidimensional Perfectionism Scale is one of the most world widely used measures of perfectionism. OBJECTIVE: To analyze the psychometric properties of the Portuguese version of the Frost Multidimensional Perfectionism Scale. METHODS: Two hundred and seventeen (178 females) s [...] tudents from two Portuguese Universities filled in the scale, and a subgroup (n = 166) completed a retest with a four weeks interval. RESULTS: The scale reliability was good (Cronbach alpha = .857). Corrected item-total correlations ranged from .019 to .548. The scale test-retest reliability suggested a good temporal stability with a test-retest correlation of .765. A principal component analysis with Varimax rotation was performed and based on the Scree plot, two robust factorial structures were found (four and six factors). The principal component analyses, using Monte Carlo PCA for parallel analyses confirmed the six factor solution. The concurrent validity with Hewitt and Flett MPS was high, as well as the discriminant validity of positive and negative affect (Profile of Mood Stats-POMS). DISCUSSION: The two factorial structures (of four and six dimensions) of the Portuguese version of Frost Multidimensional Perfectionism Scale replicate the results from different authors, with different samples and cultures. This suggests this scale is a robust instrument to assess perfectionism, in several clinical and research settings as well as in transcultural studies.

Ana Paula Monteiro, Amaral; Maria João, Soares; Ana Telma, Pereira; Sandra Carvalho, Bos; Mariana, Marques; José, Valente; Vasco, Nogueira; Maria Helena, Azevedo; António, Macedo.

83

Frost-resistance of red ceramic products  

Directory of Open Access Journals (Sweden)

Full Text Available The present work is a study about degradation occurring with red ceramics whenever they are exposed to the environmental conditions of a cold and humid climate. Four different types of clay from Rio Grande do Sul were studied: two of them from the Serra Geral formation, and the other two from the formation of Strada Nova, which are commonly used to make roof tiles. The clay was characterised to identify its chemical and mineralogical composition. Also the physical properties were researched. In the ceramic processing, the pressure with four different sintering temperatures (850ºC, 900ºC, 950ºC, and 1000ºC at three different intervals (3, 12, and 24 hours were used. The ceramic materials thus obtained were characterised according to their physical properties (water absorption, total density, porosity, and porous size, and mechanical (mechanical resistance over four points. For the characterisation of the degradation mechanism, some trials were carried out to obtain the coefficient of saturation and on frost and defrost cycles. The microstructural analysis was made with a scanning electronic microscopy. On the basis of the results obtained, a model for the degradation mechanism is presented, and a degradation factor which relates the total volume of mesopores to the standard size of mesopores is suggested. It was concluded that the red ceramic products more prone to be frost-resistant are those presenting a degradation factor below 100.

Se estudia la degradación que sufre la cerámica roja cuando se expone a la acción de los climas fríos e húmedos. La experimentación se ha realizado con cuatro arcillas de la son expuestas a los climas fríos y húmedos. Se investigaron cuatro diferentes arcillas de la provincia del Rio Grande do Sul, que se emplean tradicionalmente en la fabricación de tejas. Dos de ellas pertenecen a la formación de la Serra Geral y las otras dos de la formación Estrada Nova. La caracterización de las arcillas ha incuido: composición química y mineralógica, granulometría, plasticidad, humedad de moldeo, contracción lineal de secado e resistencia a la flexión de piezas secas. Las probetas han sido moldeadas por prensado, y cocidas a 850º, 900º, 950º y 1000ºC con tres tiempos de permanencia a la temperatura máxima (3, 12 y 24 horas. En las probetas cocidas se ha determinada la capacidad de absorción de agua, la densidad total, la porosidad abierta, la distribución del tamaño de los poros y la resistencia a la flexión en cuatro puntos. En el estudio del comportamiento a los ciclos de congelación-descongelación, ha incluido, además de la ciclación de las probetas, la determinación de sus coeficientes de saturación y el análisis microestructural, por microscopia electrónica de barrido, de probetas de probetas que han sufrido la ciclación. Apoyándose en los datos obtenidos, los autores presentan un modelo para el mecanismo de degradación, y sugieren un factor de degradación, que relaciona el volumen total de mesoporos con su tamaño medio. Según este modelo, los productos cerámicos de arcilla, que tienen una lata probabilidad de ser resistentes a los ciclos de congelación - descongelación, son aquellos cuyo factor de degradación es menor de 100.

Ramires, M. V. V.

2000-02-01

84

General frost growth mechanism on solid substrates with different stiffness.  

Science.gov (United States)

Preventing or delaying frost formation on surfaces is of significant importance in many aspects of our daily life. Despite many efforts and improvements recently achieved in the design of new icephobic materials and substrates, not all proposed solutions are universally applicable and frost formation still remains a problem in need of further flexible solutions. In this respect, we propose to take benefit from the tunable viscoelastic properties of soft polymer gel substrates, since they are known to strongly influence the dropwise condensation process of water, and to investigate condensation frosting on them. Using polymer gels with different stiffness and a hard substrate as a reference, we demonstrate their ability to delay frost formation compared to recent results reported in the literature on other solid substrates and in particular on superhydrophobic surfaces. By investigating the frost front propagation we singled out a general behavior of its dynamic evolution consisting of two processes presenting two different time scales. This general growth appears to be independent of experimental conditions as well as substrate stiffness. PMID:24456462

Petit, Julien; Bonaccurso, Elmar

2014-02-01

85

The Rockfall Buzzsaw: Quantifying the role of frost processes on mountain evolution  

Science.gov (United States)

The height and relief of high mountains reflects a balance between uplift, caused by tectonic and isostatic forces, and erosion, by fluvial, glacial, periglacial, and hillslope processes. Recently, models of mountain evolution have focused on the importance of glaciers in eroding deep valleys, a process referred to as the "glacial buzzsaw". Little attention has been paid to the role of periglacial processes, despite large scree slopes and rubble-covered glaciers being common in mountains. Frost cracking induced rockfall erosion has wide acceptance in the literature and a number of local studies have calculated high rockfall erosion rates in cold environments; but the question remains, how important is frost cracking in eroding bedrock in mountainous environments? We quantify how and where ice-driven mechanical erosion occurs in cold, bedrock-dominated landscapes using a simple one-dimensional numerical heat flow model. In our model, ice grows by water migration to colder regions in shallow rock by the reduction in chemical potential associated with intermolecular forces between ice and mineral surfaces, a process called segregation ice growth. Positive MAT sites are characterized by intense cracking in the top meter of the rock mass and a maximum frost penetration of ~4m. In contrast, negative MAT areas have an order of magnitude less intense cracking that primarily occurs at depths between 50 and 800 cm. This suggests that periglacial erosion may be concentrated in a narrow elevation range (corresponding to areas with a MAT between 0 and 2°C). At higher MATs ice growth is limited to very shallow depths. As MATs dip below zero, frost cracking intensity is reduced considerably resulting in a high and frozen condition. These results suggest that rocks with a fracture spacing of less than 400cm provide more sites for the nucleation and growth of segregation ice, and are therefore more susceptible to frost-induced bedrock weathering. To quantify the effect of ice weathering, we compared the elevation, rock fracture spacing, and the rockfall erosion rate for three areas, the eastern Southern Alps, New Zealand (fracture spacing of scree slopes, rapid rockfall erosion rates (~0.1 mm/yr), and rounded peaks whose maximum elevation corresponds with the ~0°C isotherm. The eastern Sierra Nevada has small scree slopes and steep pinnacled ridges and peaks above the -5°C isotherm, consistent with the high and frozen scenario. In Utah the highest rockfall frequencies occur in coincidence with the 0.5°C isotherm. These results hint at an interplay between mountain height and rock fracture spacing, such that the height of mountains with highly fractured rocks may be limited by the intense frost processes coincident with the 1°C isotherm. In this case, mountain elevations may be limited by a rockfall buzzsaw, which efficiently erodes bedrock within a narrow elevation band, the location of which is controlled by glacial- interglacial climate cycles.

Hales, T.; Roering, J. J.

2006-12-01

86

Far-infrared spectra of CO2 clathrate hydrate frosts  

Science.gov (United States)

As a product of our interest in remote sensing of planetary ices, frost samples of CO2 clathrate hydrate were grown by depositing water vapor on a cooled surface and pressurizing the resulting water frost with CO2 gas. At pressures above the dissociation pressure of the clathrate, the samples exhibit an absorption peak at 75 cm (sup -1). At pressures below the dissociation pressure, the peak disappears. Since the free CO2 molecule does not have rotational or vibrational absorption in this region, the absorption is attributed to a CO2 rattling mode within a clathrate cage.

Landry, J. C.; England, A. W.

1993-01-01

87

Soils  

Science.gov (United States)

The purpose of the handout is to identify the three major types of soils: pedalfer, pedocal, and laterite, and to understand the soil profile. This is accomplished with brief descriptions of the soil horizons and the designation of common elements to pedalfers, pedocals, and laterite soils. The handout is concluded with a discussion of soil erosion. Links are provided to the online Physical Geology resources at Georgia Perimeter College.

Pamela Gore

1995-08-29

88

Statistical Examination of Frost Characterization: A Case of Global Warming Impact in Jordan  

Directory of Open Access Journals (Sweden)

Full Text Available Radiation and advection frost are common in Jordan as well as other neighboring countries as they face several frost waves each year during the late months of winter. Recently, many frost episodes hit the valley and damaged the crops that were compensated by millions of dollars by the Jordanian Government. This manuscript addresses and characterizes frost, and assesses the role of global warming in impacting frost in terms of its frequency, severity, and total number of frost days per year. A comprehensive statistical approach was used. The paper indicates that frost waves will continue to hit in the near future regardless of the fact that Earth is moving towards warmer conditions. Agricultural and financial authorities should be urged to minimize frost damage by considering installing wind fans in Jordan valley as an active method in addition to implementing good farm practices (as a passive methods where deemed necessary.

Moshrik R Hamdi

2011-08-01

89

Quantitative trait loci of frost tolerance and physiologically related trait in faba bean (Vicia faba L.)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In faba bean, field based winter-hardiness is a complex trait that is significantly correlated to frost tolerance. Frost tolerance could be used to indirectly select for faba bean winter-hardiness. The aim of this study was to identify putative QTL associated with frost tolerance and auxiliary traits and to quantify the efficiency of marker assisted selection. Thus, 101 recombinant inbred lines derived from the cross between two frost tolerant lines were tested for their hardened and unharden...

Arbaoui, Mustapha; Link, Wolfgang; Satovic, Zlatko; Torres, Ana-maria

2008-01-01

90

Martian Seasonal CO2 Frost Indicating Decameter-Scale Variability in Buried Water Ice  

Science.gov (United States)

Several new lines of evidence indicate that subsurface water ice (ground ice) on Mars is more complexly distributed, and in variable concentrations, than had been previously envisioned. Understanding the current distribution of ground ice is a fundamental part of understanding how this ice was emplaced and the recent past climate conditions under which icy deposits formed and subsequently evolved. In this work we examine the seasonal defrosting of CO2 observed by HiRISE as an indicator of decameter-scale ground-ice heterogeneity. It is well known that CO2 dry ice accumulates on the martian surface in winter. The amount of dry ice and the time it spends on the ground depends strongly on surface properties. A readily observable attribute is the "crocus date", the season (Ls) when CO2 completely sublimates, exposing the soil surface. Many factors can affect the crocus date, but perhaps most important are the properties of CO2 frost and of the surface soil. We examine HiRISE observations, spanning more than a martian year, for decameter-scale patterns of CO2 frost and the crocus date. Year-to-year repeatability of CO2 ice patterns, both in polygon troughs and decameter-size patches, along with a lack of topography nor aeolian redistribution, suggests that differences in the surface substrate is the root cause for these patterns. In addition, only CO2 slab ice (solid, non-porous dry ice) is indicated throughout the observed seasons and at all spatial scales (down to meter scale), as evidenced by albedo (HiRISE and TES) and IR spectra (CRISM). In addition, the low emissivity and high albedo of fine-grained particulate CO2 frost would result in a crocus date much earlier than even the earliest observed. We present two scenarios of substrate differences which explain the observations: (i) the ice-table depth varies away from atmospheric equilibrium, such that a thicker "dry-soil" layer occurs in disequilibrium where the CO2 ice lingers longest; and (ii) the H2O concentration at the ice table and below is less than pore filling (or that subsurface pure-water-ice deposits contain substantial open porosity) in these same lingering CO2-ice locations. In the later case these CO2 ice patches may be outlining deposits of the light-toned, friable, pure water ice as was discovered by Phoenix. Neither of these two ground-ice scenarios is predicted by the current models of ground ice stability and dynamics. These results indicate substantial decameter-scale heterogeneity in the ground ice distribution and local disequilibrium with the current martian climate.

Mellon, M. T.; Hansen, C. J.; Cull, S.; Arvidson, R. E.; Searls, M.

2011-12-01

91

Annual variations of frost table in Kangerlussuaq Airport, western Greenland  

DEFF Research Database (Denmark)

Ground-penetrating radar (GPR) has been used to study the annual variations of the frost table beneath the southern parking area at Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white in order to reduce further development of depressions in the asphalt pavement initiated by permafrost degradation. One of these white painted areas has been used in the investigations to compare the annual variations of the frost table underneath a normal black asphalt surface to with that below a more reflective surface. The investigations were carried out from July 2005 until August 2006. The GPR measurements have shown a clear correlation between the use of the reflective surface and a reduced depth in the annual variations to the frost table. In late summer (August) the difference in the depths to the frost table is almost 20 ns, which corresponds to approximately 0.9 m. This constitutes a major difference in the thermal conditions below the reflective surface and the normal black asphalt surface.

JØrgensen, Anders Stuhr; Ingeman-Nielsen, Thomas

2007-01-01

92

Genetic Architecture of Winter Hardiness and Frost Tolerance in Triticale  

Science.gov (United States)

Abiotic stress experienced by autumn-sown crops during winter is of great economic importance as it can have a severe negative impact on yield. In this study, we investigated the genetic architecture of winter hardiness and frost tolerance in triticale. To this end, we used a large mapping population of 647 DH lines phenotyped for both traits in combination with genome-wide marker data. Employing multiple-line cross QTL mapping, we identified nine main effect QTL for winter hardiness and frost tolerance of which six were overlapping between both traits. Three major QTL were identified on chromosomes 5A, 1B and 5R. In addition, an epistasis scan revealed the contribution of epistasis to the genetic architecture of winter hardiness and frost tolerance in triticale. Taken together, our results show that winter hardiness and frost tolerance are complex traits that can be improved by phenotypic selection, but also that genomic approaches hold potential for a knowledge-based improvement of these important traits in elite triticale germplasm. PMID:24927281

Liu, Wenxin; Maurer, Hans Peter; Li, Guoliang; Tucker, Matthew R.; Gowda, Manje; Weissmann, Elmar A.; Hahn, Volker; Würschum, Tobias

2014-01-01

93

Increasing the frost resistance of facade glazed tiles  

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the protective properties of a coating of boron oxides and zirconium oxides applied as a glaze to ceramic tiles by conducting a series of tests to determine the frost resistance, the propensity to absorb water, the moisture expansion coefficient, the fracture behavior, and the effect of thermal cycling on the oxides. Results are graphed and tabulated.

Egerev, V.M.; Zotov, S.N.; Romanova, G.P.

1986-09-01

94

Soils  

...Directive:Identification of areas at risk of soil erosion, organic matter decline, compaction, salinisation and landslides and for Member States to establish programmes of measuresMeasures to address soil contamination...

95

?Determination of Frost Free Season by Using Dates of First and Last Advection and Radiation Frosts in Zanjan, Gazvin and Tehran Regions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dates of start and end of frost based on minimum shelter temperature equal to or less than 0°C were studied in Zanjan, Ghazvin and Tehran during 1961-2000. The cause of these frosts was determined by weather parameter values at observation hours and the aid of synoptic maps. Frost series based upon last spring or first fall advection are defined and found to be random and normally distributed. The "potential growing season", defined as the interval between spring last and f...

Noohi, K.; Sahraeian, F.; Pedram, M.; Sedaghat Kerdar, A.

2009-01-01

96

Susceptibility Testing  

Science.gov (United States)

... this page helpful? Also known as: Sensitivity Testing; Drug Resistance Testing; Culture and Sensitivity; C & S; Antimicrobial Susceptibility Formal name: Bacterial and Fungal Susceptibility Testing Related tests: Urine Culture ; Blood Culture ; Bacterial Wound Culture ; AFB Testing ; ...

97

Soils  

International Nuclear Information System (INIS)

For Austria there exists a comprehensive soil data collection, integrated in a GIS (geographical information system). The content values of pollutants (cadmium, mercury, lead, copper, mercury, radio-cesium) are given in geographical charts and in tables by regions and by type of soil (forests, agriculture, greenland, others) for the whole area of Austria. Erosion effects are studied for the Austrian region. Legal regulations and measures for an effective soil protection, reduction of soil degradation and sustainable development in Austria and the European Union are discussed. (a.n.)

98

TuBaFrost: European virtual tumor tissue banking.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

TuBaFrost is a consortium responsible for the task to create a virtual European human frozen tumor tissue bank, composed of high quality frozen tumor tissue collections with corresponding accurate diagnosis stored in European cancer centers and universities, searchable on the Internet, providing rules for access and use and a code of conduct to comply with the various legal and ethical regulations in European countries. Such infrastructure would enlarge tissue availability and accessibility i...

Riegman, Ph; Oomen, Mh; Dinjens, Wn; Oosterhuis, Jw; Lam, Kh; Spatz, A.; Ratcliffe, C.; Knox, K.; Mager, R.; Kerr, D.; Pezzella, F.; Damme, B.; Vijver, M.; Boven, H.; Morente, Mm

2006-01-01

99

The frost peat production; Routapalaturpeen tuotantoketjun tekniikka, talous ja ympaeristoevaikutukset  

Energy Technology Data Exchange (ETDEWEB)

The frost peat production means the cutting of frozen peat in the winter time. The aim of this study is to test the possibilities to prolong the peat production season and to produce peat pieces for the horticultural peat industry. In the frost peat production method the frozen peat field is sawed throughout the length and breadth of by a circle saw. The sawed peat pieces are loosened from the field by a so-called `splitter`. The circle saw is equipped with the five circle saw blades (diameter 90 cm). The distance of the blades is adjustable. The splitter is equipped with a horizontal position blade (width 35 cm). The dimensions of the peat pieces are changeable, but from the point of drying the upper limit of the side of the peat cube can be 15-20 cm. The frost peat production method is technically suitable for production of slightly decomposed (H1-5) energy and horticultural peat. The energy peat pieces are allowed to dry up 70-75 % moisture content on the cutting field and then the pieces can be ridged by the screening ridger. If necessary, the ridges can be turned over. In the frost peat production, the conventional sod peat winning machines can be used in the following stages of the working tasks: harrowing, ridging, loading, turning of ridges and stockpiling. The measured output of the circle saw was about 45-50 m{sup 3}/h of energy peat and 58-63 m{sup 3}/h of horticultural peat. The output of the splitter was 120-150 m{sup 3}/h. Theoretically, the output of circle saw and the splitter can easily be doubled. Thereafter the production costs will be about 19 FIM/MWh of energy peat and 18,6 FIM/m{sup 3} of horticultural peat

Nyroenen, T. [Vapo Oy, Jyvaeskylae (Finland); Leiviskae, V. [Oulu Univ. (Finland). Thule Inst.

1997-12-01

100

Frost resistance of concrete with crushed brick as aggregate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The investigation included concrete made by using recycled brick as aggregate. Experimental work included several types of concrete made with the same cement content (385 kg/m3), and same consistency (slump about 1 cm). Recycled brick and combination of natural river aggregate and recycled brick were used as aggregates. The influence of percentage and grain size of crushed brick aggregate on concrete compressive strength, water absorption and frost resistance were observed. On the basis of th...

Jankovi? Ksenija; Bojovi? Dragan; Nikoli? Dragan; Lon?ar Ljiljana; Romakov Zoran

2010-01-01

 
 
 
 
101

Portrayal of Realism and Rationalism in the Selected Poems of Robert Frost  

Directory of Open Access Journals (Sweden)

Full Text Available Robert Frost (1874-1963 is a famous American Poet. As most of his poems are autobiographical in subject, it is evident that he has been mostly influenced by the environment around him in composing his masterpieces. Frost’s themes are very simple in the surface meaning endowed with an easily understandable diction and a liberal style of writing. Yet, a careful study of his works vividly reveals his greatness as a ‘true’ judge of various critical aspects associated with the everyday experiences of the humans. His major characters- the narrators in “Stopping by Woods on a Snowy Evening”, “Mending wall” and “The Road not Taken” are viewed as the real people with real struggles in real life. It is seen that Frost’s poetry is highly connotative and the same reader can interpret the poetry of Robert Frost in multiple ways in multiple settings. The present article aims at critically examining Frost’s ‘realistic’ and ‘rationalistic’ approaches in the elevation of human nature under the broad spectrum of human life. This article also aims at proving that no poem of Frost ends in an absolute imagination because Frost himself seems to believe in realism as the ultimate fate of the individuals though fancy and imagination provides a temporary relief to the disturbed soul.

Sathi Veerraghava Reddy

2014-06-01

102

Frosting and defrosting of air-coils - results from laboratory testing  

Energy Technology Data Exchange (ETDEWEB)

Frosting of air-coils is an important factor in the design and operation of air-source heat pumps, heat recovery ventilators, cooling and refrigeration equipment etc. This report presents results from laboratory testing of two brine-cooled air-coils under frosting conditions. The coils have the same number of plane, continuous fins, 4 tube rows with 12 tubes in each row, tube spacing of 50 mm and fin spacing of 3 and 6 mm respectively. The original purpose of the test program was to compare various possible indicators of coil frosting and to analyze the possible effects of different control strategies on coil capacity and the COP of the system (the analysis will be presented in a separate report). Tests involved inlet air temperatures of -7 and +2 degC, variation of humidity between 70 and 100% RH (including simulated rain), velocities in the range 1 to 4 m/s, and specific cooling loads from 50 to 150 W/m{sup 2}. Test results include variations due to frosting of e.g. cooling capacity, COP, air flow and pressure drop, fan power, air outlet temperature and humidity, coil temperature, frost mass, and frosting time. Results also include the subsequently required defrost time, defrost energy and collected mass of defrost water. The frosting process was interrupted when the air flow had decreased to 30% of the original value with a non-frosted coil. The results clearly show the advantage of demand controlled defrosting with variations in frosting time between 2 h with high humidity/high specific cooling load up to, for practical purposes, infinite frosting times with low humidity/low specific cooling load. The accumulated frost mass during one frosting cycle varied from less than 0.02 kg/m{sup 2} up to approximately 0.4 kg/m{sup 2}. 23 refs, 93 figs, 89 tabs

Fahlen, P.

1996-12-31

103

Frost Formation Problem in the Development of a Hypersonic Turbojet Engine  

Science.gov (United States)

The Japan Aerospace Exploration Agency has developed a hypersonic aircraft flying at Mach 5. A precooled turbojet engine is the candidate of the engine for the hypersonic aircraft. The precooled turbojet engine has a heat exchanger(precooler) which cools the breathed air by using cryogenic propellant, such as liquid hydrogen. The precooler has a problem that frost forms on the cooling tubes of the precooler, and the frost decrease the engine performance. Some approaches to deal with the frost formation problem have employed in the development. In this paper, those approaches are introduced and the results of some fundamental studies about frost are also shown.

Fukiba, Katsuyoshi; Sato, Tetsuya; Kobayashi, Hiroaki; Ohkubo, Hidetoshi

104

Experimental assessment on the frost sensitivity during leaf development of juvenile Fagus sylvatica L.  

Science.gov (United States)

Late frost events in spring shape species distribution as well as reduce productivity. Till now, it is still not clear if future warming will lead to more frequent / stronger / more harmful frost damages in forestry and agriculture or not. Since the variability of extremes is increasing it seems that the risk of late frost damages in many regions may not decrease, even if the mean air temperature in general is increasing. A late frost event is only harmful if plants have initiated their leaf / flower development. Closed buds are usually very frost tolerant. However, once leaves develop after mild and warm spring periods, the new tissue is especially sensitive to freezing temperatures. Therefore not only the date of the last frost but also the weather history of the late winter / early spring determines if a frost event might result in frost damage or not. Tissue sensitivity to frost varies among species, but even within species there might be differences in frost tolerance during the different stages in leaf development. We set up an experiment to identify the frost risk in connection with the developmental stage of the leaves of juvenile beech. In order to vary the timing of frost events, we placed 1-year old potted beech trees 7times overnight in a climate chamber, in which the air temperature was cooled down to - 3° for five hours. For each tree the phenological stages were observed before and after the frost, the percent of damage was estimated after two days; additionally phenology of the damaged plants was observed weekly to document the recovery of their damage till May 23, 2013. Only about 30% of the plants were damaged. In general it can be stated if damage occurred it was a severe damage, only very few plants sustained little damage. We observed dependence on the date of the freezing event, rather than on specific phenological phases - the later the frost was applied the more plants were damaged. Damaged plants recovered relatively rapidly from the frost damage; three to six weeks after the event most of the damage plants were foliated equally to non-damaged plants. Only a few plants did not recover at all from the frost event.

Estrella, Nicole; Menzel, Annette

2014-05-01

105

Evaluation of the blackberry germplasm (Rubus spp. frost resistance at the Research Institute for Fruit Growing Pitesti  

Directory of Open Access Journals (Sweden)

Full Text Available The study concerns the evaluation of damage caused by strong frosts in the winter 2009-2010 to the blackberry plants in the experimental field of the RIFG Pitesti-M ? r ? cineni. There were taken under study 42 blackberry genotypes of the Institute collection, 11 selections originated from 6 hybrid combinations made in 2000 and 350 hybrids resulted from the 15 hybrid combinations, made in 2002. The objective of the work was to evaluate and identify genotypes with genetic resistance to negative temperatures extremely severe (-24.4 ? C in air and -25.5°C on snow surface knowing that the threshold resistance of the thornfree blackberry is the minimum temperature -14° .. -15°C and of the thorny ones -17°.. -18°C. The goal was to introduce the most resistant genotypes as basic genitors in the breeding program for the improving the frost resistance of the varieties and to promote them in culture. The evaluation was done on the stems, buds and shoots of plants in the bud-break and growth of fruiting shoots phenophases. It was found that the most varieties, selections and hybrids with semierect and erect habit were strongly damaged, with some exceptions that will be presented below, while the least affected were those with creeping habit and stems bent to the ground soil. Of all the genotypes Wilson Early variety, selections ARK 613 and ARK 609, 2 / 21 and hybrids : N x A-T 12, H -N1, H T4-R3, N x H-2/11 ? i N x H 2/T 13 were found to have high degree resistance to the extremely frosts of the 2009-2010 winter.

Gheorghe Mladin

2010-01-01

106

Nowcasting in the FROST-2014 Sochi Olympic project  

Science.gov (United States)

FROST (Forecast and Research: the Olympic Sochi Testbed) 2014 is a WMO WWRP international project aimed at development, implementation, and demonstration of capabilities of short-range numerical weather prediction and nowcasting technologies for mountainous terrain in winter season. Sharp weather contrasts and high spatial and temporal variability are typical for the region of the Sochi-2014 Olympics. Steep mountainous terrain and an intricate mixture of maritime sub-tropical and Alpine environments make weather forecasting in this region extremely challenging. Goals of the FROST-2014 project: • To develop a comprehensive information resource of Alpine winter weather observations; • To improve and exploit: o Nowcasting systems of high impact weather phenomena (precipitation type and intensity, snow levels, visibility, wind speed, direction and gusts) in complex terrain; o High-resolution deterministic and ensemble mesoscale forecasts in winter complex terrain environment; • To improve the understanding of physics of high impact weather phenomena in the region; • To deliver forecasts (Nowcasts) to Olympic weather forecasters and decision makers and assess benefits of forecast improvement. 46 Automatic Meteorological Stations (AMS) were installed in the Olympic region by Roshydromet, by owners of sport venues and by the Megafon corporation, provider of mobile communication services. The time resolution of AMS observations does not exceed 10 minutes. For a subset of the stations it is even equal to 1 min. Data flow from the new dual polarization Doppler weather radar WRM200 in Sochi was organized at the end of 2012. Temperature/humidity and wind profilers and two Micro Rain Radars (MRR) will supplement the network. Nowcasting potential of NWP models participating in the project (COSMO, GEM, WRF, AROME, HARMONIE) is to be assessed for direct and post-processed (e.g. Kalman filter, 1-D model, MOS) model forecasts. Besides the meso-scale models, the specialized nowcasting systems are expected to be used in the project - ABOM, CARDS, INCA, INTW, STEPS, MeteoExpert. FROST-2014 is intended as an 'end-to-end' project. Its products will be used by local forecasters for meteorological support of the Olympics and preceding test sport events. The project is open for new interested participants. Additional information is available at http://frost2014.meteoinfo.ru.

Bica, Benedikt; Wang, Yong; Joe, Paul; Isaac, George; Kiktev, Dmitry; Bocharnikov, Nikolai

2013-04-01

107

Frost resistance of concrete with crushed brick as aggregate  

Directory of Open Access Journals (Sweden)

Full Text Available The investigation included concrete made by using recycled brick as aggregate. Experimental work included several types of concrete made with the same cement content (385 kg/m3, and same consistency (slump about 1 cm. Recycled brick and combination of natural river aggregate and recycled brick were used as aggregates. The influence of percentage and grain size of crushed brick aggregate on concrete compressive strength, water absorption and frost resistance were observed. On the basis of the results obtained during experimental research, a general conclusion can be drawn that the application of recycled concrete as aggregate can lead to new composites with satisfactory physical-mechanical properties.

Jankovi? Ksenija

2010-01-01

108

Fatores relacionados à suscetibilidade da erosão em entressulcos sob condições de uso e manejo do solo Factors influencing susceptibility to interrill soil erosion under different land use and management conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Neste trabalho foram avaliados fatores relacionados com a suscetibilidade a erosão em entressulcos de um Neossolo Litólico submetido a diferentes intensidades de uso e manejo do solo. O experimento foi realizado em condições de laboratório, utilizando-se amostras deformadas de solo colocadas em parcelas experimentais (0,23 m2 e declividade de 0,09 m m-1. O delineamento experimental utilizado foi em blocos casualizados, em que foram aplicadas chuvas simuladas com intensidade de 100 mm h-1 para os seguintes tratamentos: (I solo cultivado com fumo sob preparo convencional (PC; (II solo cultivado com fumo sob plantio direto (PD e (III solo sob mata nativa (MN. Para avaliar a suscetibilidade a erosão em entressulcos utilizaram-se índices referentes à relação energia cinética total (chuva e escoamento sobre perda de solo, taxa média de desagregação e índice de estabilidade de agregados, cujos resultados mostraram que os fatores relacionados com a suscetibilidade a erosão em entressulcos estão associados não apenas com características e propriedades que conferem coesividade ao solo, mas, também, com condicionantes que afetam a hidráulica do escoamento e, consequentemente, a fase de transporte dos sedimentos.This study evaluated factors related to the suscetibility to the interrill soil erosion in an Entisol subjected to different degrees of soil use and management. The experiment was carried out under laboratory conditions using samples collected from tobacco fields and disturbed soil placed in erosion pans measuring (0.23 m2 with a slope of 0.09 m m-1. The experimental design was in randomized blocks. Simulated rainfall intensity of 100 mm h-1 was applied to the following treatments: (I conventionally tilled soil; (II no-till soil; and (III native forest soil. Total kinetic energy (rainfall and runoff to soil loss, average rate of detachment, and aggregate stability indexes were used to assess susceptibility to interrill erosion. Results show that the factors related with the susceptibility to interrill erosion are associated not just to the characteristics and properties that confer cohesivity to soil, but also to those factors that affect runoff hydraulics and therefore the sediment transport phase as well.

Flávio P. de Oliveira

2012-04-01

109

Fatores relacionados à suscetibilidade da erosão em entressulcos sob condições de uso e manejo do solo / Factors influencing susceptibility to interrill soil erosion under different land use and management conditions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Neste trabalho foram avaliados fatores relacionados com a suscetibilidade a erosão em entressulcos de um Neossolo Litólico submetido a diferentes intensidades de uso e manejo do solo. O experimento foi realizado em condições de laboratório, utilizando-se amostras deformadas de solo colocadas em parc [...] elas experimentais (0,23 m2) e declividade de 0,09 m m-1. O delineamento experimental utilizado foi em blocos casualizados, em que foram aplicadas chuvas simuladas com intensidade de 100 mm h-1 para os seguintes tratamentos: (I) solo cultivado com fumo sob preparo convencional (PC); (II) solo cultivado com fumo sob plantio direto (PD) e (III) solo sob mata nativa (MN). Para avaliar a suscetibilidade a erosão em entressulcos utilizaram-se índices referentes à relação energia cinética total (chuva e escoamento) sobre perda de solo, taxa média de desagregação e índice de estabilidade de agregados, cujos resultados mostraram que os fatores relacionados com a suscetibilidade a erosão em entressulcos estão associados não apenas com características e propriedades que conferem coesividade ao solo, mas, também, com condicionantes que afetam a hidráulica do escoamento e, consequentemente, a fase de transporte dos sedimentos. Abstract in english This study evaluated factors related to the suscetibility to the interrill soil erosion in an Entisol subjected to different degrees of soil use and management. The experiment was carried out under laboratory conditions using samples collected from tobacco fields and disturbed soil placed in erosion [...] pans measuring (0.23 m2) with a slope of 0.09 m m-1. The experimental design was in randomized blocks. Simulated rainfall intensity of 100 mm h-1 was applied to the following treatments: (I) conventionally tilled soil; (II) no-till soil; and (III) native forest soil. Total kinetic energy (rainfall and runoff) to soil loss, average rate of detachment, and aggregate stability indexes were used to assess susceptibility to interrill erosion. Results show that the factors related with the susceptibility to interrill erosion are associated not just to the characteristics and properties that confer cohesivity to soil, but also to those factors that affect runoff hydraulics and therefore the sediment transport phase as well.

Flávio P. de, Oliveira; Diogo C., Buarque; Ana C., Viero; Gustavo H., Merten; Elemar A., Cassol; Jean P. G., Minella.

2012-04-01

110

Air-cooler with frosting and defrosting; Luftkylare med paafrysning och avfrostning  

Energy Technology Data Exchange (ETDEWEB)

This report summarizes experience from SP research and assignments in the field of frosted air-coolers. It presents the fundamentals of frost growth and describes the pros and cons of alternative methods of defrosting and its control. The material has been compiled for educational purposes in the Masters program at Chalmers Technical University.

Fahlen, Per

2000-07-01

111

[Association of microsatellite loci alleles of the group-5 chromosomes with frost resistance of winter wheat].  

Science.gov (United States)

Analysis of frost resistance and microsatellite analysis of the group-5 chromosomes were performed on parental varieties and recombinant-inbred lines F7 Luzanovka odesskaya/Odesskaya krasnokolosaya. Allelic differences for Xcfd7-5B Xwmc415-5B and Xgwm 182-5D microsatellite loci were associated with the level of frost resistance of the lines. PMID:24228492

Halaieva, M V; Fa?t, V I; Chebotar, S V; Halaiev, O V; Syvolap, Iu M

2013-01-01

112

Simulating transmission and control of Taenia solium infections using a reed-frost stochastic model  

DEFF Research Database (Denmark)

The transmission dynamics of the human-pig zoonotic cestode Taenia solium are explored with both deterministic and stochastic versions of a modified Reed-Frost model. This model, originally developed for microparasitic infections (i.e. bacteria, viruses and protozoa), assumes that random contacts occur between hosts and that hosts can be either susceptible, infected or ‘recovered and presumed immune'. Transmission between humans and pigs is modelled as susceptible roaming pigs scavenging on human faeces infected with T. solium eggs. Transmission from pigs to humans is modelled as susceptible humans eating under-cooked pork meat harbouring T. solium metacestodes. Deterministic models of each scenario were first run, followed by stochastic versions of the models to assess the likelihood of infection elimination in the small population modelled. The effects of three groups of interventions were investigated using the model: (i) interventions affecting the transmission parameters such as use of latrines, meat inspection, and cooking habits; (ii) routine interventions including rapid detection and treatment of human carriers or pig vaccination; and (iii) treatment interventions of either humans or pigs. It is concluded that mass-treatment can result in a short term dramatic reduction in prevalence, whereas interventions targeting interruption of the life cycle lead to long-term reduction in prevalence.

Kyvsgaard, Niels Chr.; Johansen, Maria Vang

2007-01-01

113

Frost flower influence on springtime boundary-layer ozone depletion events and atmospheric bromine levels  

Science.gov (United States)

Springtime boundary layer ozone depletion events have been observed in both the Arctic and Antarctic. It has been suggested that these bromine-catalyzed depletion events may be caused by bromine released from frost flowers. We have measured the pH and ion concentrations of snow and frost flowers in the Ross Island, Antarctica area and find that if these are representative, frost flowers are unlikely to be a direct source of atmospheric bromine. The pH of the sampled frost flowers is too alkaline to support the release of molecular bromine resulting from the heterogeneous reaction of HOBr with Br ions. It is more likely that frost flowers are a source of aerosol bromine from which gas-phase bromine can be released through subsequent reactions in aerosol form or on the snow pack.

Kalnajs, Lars E.; Avallone, Linnea M.

2006-05-01

114

Frost as a first wall for the ICF Laboratory Microfusion Facility  

International Nuclear Information System (INIS)

We introduce the concept of using frost as the first wall of the ICF Laboratory Microfusion Facility being designed to produce 200--1000 MJ of thermonuclear yield. We present one design incorporating 2 cm of frost deposited at 0.1 g/cm3 on an LN-cooled fiber-reinforced polymer substrate. We calculate that such a frost layer will protect the substrate from ablation by target x rays and debris, and from shock-induced spallation. Postshot washdown with water should permit low-activation operation, and should preserve the original wall properties. We expect the impact of the frost on laser optics to be minimal, and expect the preshot lifetime of thermally unprotected cryogenic targets to be extended by operating the wall at 100-150 K. Moreover, we believe that such a frost first wall will involve little technical risk, and will be inexpensive to construct and operate. 4 refs., 1 fig

115

Evaluation and improvement of frost durability of clay bricks  

Science.gov (United States)

In cold regions like Canada, frost action was reported to be the major cause of disintegration of brick veneer. Two approaches to ensure frost durability of clay bricks were studied in this research. One involved the evaluation of durability, while the other studied the improvement of durability through impregnation. In order to carry out these studies, three major objectives were set out for this research. They were: (1) to develop an index to evaluate frost durability, (2) to investigate the feasibility of using nondestructive methods to evaluate durability, and (3) to study the effect of impregnation with different materials on improving durability. It was intended in this research to develop a general durability index for clay bricks, irrespective of the manufacturing process adopted. The performance of the brick was studied using laboratory freeze-thaw test. As the time and facility requirements necessary for the unidirectional freezing test were beyond the constraints which existed in this research, an accelerated omnidirectional freeze-thaw test was used. This fact must be considered while interpreting the results from the freeze-thaw test. The study carried out to compare the performance of existing durability indices showed that they had limitations in reliably assessing durability. Therefore new durability indices were developed based on water absorption properties of bricks. These indices were found to overcome the limitations of existing indices. The feasibility study on nondestructive evaluation of durability was carried out using ultrasonic pulse velocity. New durability provisions were derived based on pulse velocity, using ASTM C216 specifications. At this stage it can be used only along with the ASTM method but it can avoid the time consuming ASTM procedure in many cases. Studies on impregnated bricks showed that there was a general shifting of pore sizes towards lower diameter region. Paraffin impregnated brick showed excellent freeze-thaw performance. The bond between brick and mortar was found to have been adversely affected due to impregnation. But more studies using brick wall component are recommended before final conclusions are drawn on brick-mortar bond strength. Paraffin was found to be the most cost effective among the impregnating materials studied.

Koroth, Surej Raghavan

116

Growth of C02 frost thickness near Chasma Borealis during northern winter and spring.  

Energy Technology Data Exchange (ETDEWEB)

Epithermal neutron fluxes measured using the Neutron Spectrometer component of the Mars OdysscNGamma-Ray Spectrometer suite of instruments were studied to determ i ne the spatial and temporal dependence of CO2 frost cover of the nor t h polar cap for L, between 329 and 99 arcoccntric longitude. This time period spans the la t e northern xvinter through summer solstice . In the absence of a CO, cuvcr, the entire basement terrain p o l eward of about +55 latitude is vm, rich in I1 :0 . The consequent enhanced abundance of hydrogen in near-surface soils leads to an anomaluusly low flux of oumardly leaking cpithcrmal ncutrons, wh i ch is a prominent signatu r e of epi t hermal neutron maps measured after about L, = 90 . Because the epithermal neutron flux rises monotonically w i t h increasing thickness of t h e CO . fros t cover, it provides a robust measure of the CO2 thickness in space and time .

Feldman, W. C. (William C.); Boynton, W. V. (William V.); Prettyman, T. H. (Thomas H.); Kelly, N.; Maurice, S. (Sylvestre)

2003-01-01

117

Evaluación de la susceptibilidad a la compactación en cuatro series de suelo bajo uso agrícola en Venezuela Evaluation of the compaction susceptibility in four series of soil under agricultural use in Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available La compactación de suelos es uno de los procesos de degradación física más común en suelos agrícolas altamente productivos y una de las causas de la reducción de la productividad. Bajo esta perspectiva, se justifica el desarrollo de metodologías que permitan estimar los riesgos de compactación de los suelos, para así prevenir o mitigar sus efectos adversos. En el presente estudio se construyeron las curvas de compactación de suelos representativos de cuatro series bajo uso agrícola en Venezuela: Valle Lindo y Valle de Quíbor (Lara, Turén (Portuguesa y El Patillal (Falcón, utilizando la metodología del Proctor estándar, con el propósito de estimar el grado de susceptibilidad de los suelos a compactarse, estimando los contenidos de humedad en los cuales presentan mayores riesgos de compactación. Asimismo, se estimaron las relaciones de las variables de la curva de compactación, humedad crítica y densidad aparente máxima, con las propiedades del suelo, distribución de tamaño de partículas y materia orgánica, y se encontró que mayores contenidos de partículas gruesas y bajos contenidos de materia orgánica originaron mayores niveles de densidad a menores contenidos de humedad, mientras que el predominio de partículas finas y altos contenidos de materia orgánica produjeron menores niveles de densidad a mayores contenidos de humedad. Los suelos FL de la serie Quíbor presentaron mayor susceptibilidad a la compactación que los suelos de similar granulometría de la serie Turén. Por otra parte, los suelos arenosos de la serie El Patillal presentaron mayor susceptibilidad que los suelos del mismo grupo textural de Quíbor y Valle Lindo.Soil compaction is one of the most common physic degradation processes in highly productive agricultural lands and one of the reasons of productivity reduction. In this situation it is justified the development of methodologies that allows estimating the soil compaction risk, and so, prevent or mitigate its adverse effects. In this study, the compaction representative curves of the soil series Valle Lindo and Valle de Quíbor (Lara State, Turén (Portuguesa State, and El Patillal (Falcón State, Venezuela, were developed, using the standard Proctor methodology, with the purpose of using it as a tool to estimate the susceptibility degree of the soil to get compaction, estimating the humidity contents in which the soil present greatest risks of compaction. There were also estimated the relationship of the variables of the compaction curve (critic moisture and maximum bulk density with the soil properties (particles size distribution and organic matter and it was found that greatest contents of thick particles and low organic matter content originated largest densities at lowest humidity contents, while the prevalence of fine particles and high organic matter content produced lower densities at higher humidity content. The FL soils of Quíbor presented greater susceptibility to compaction that soils with similar texture of Turén. On the other hand, the sandy soils of the El Patillal presented greater risks of compaction than the soils of same textural group of Quíbor and Valle Lindo.

Willians J Reyes R

2010-04-01

118

Micrometeorological and thermal control of frost flower growth on young sea ice  

DEFF Research Database (Denmark)

Frost flowers are transient crystal structures that form on new and young sea ice surfaces. They have been implicated in a variety of biological, chemical and physical processes and interactions with the atmosphere at the sea ice surface. We describe the atmospheric and radiative conditions and the physical and thermal properties of the sea ice and atmosphere that form, decay and destroy frost flowers on young sea ice. Frost flower formation occurred during a high-pressure system that caused air temperatures to drop to -30°C, with relative humidity of 70% (an under saturated atmosphere), and very calm wind conditions. The sea ice surface temperature at the time of frost flower initiation was 10-13°C warmer than the air temperature. Frost flowers grew on nodules raised above the mean surface height by 5 mm, which were 4-6°C colder than the bare, brine-wetted, highly saline sea ice surface that provided the necessary moisture. The cold nodules created potential water vapour super saturation zones abovethem with respect to air over the brine skim. Frost flowers formed and grew overnight in the absence of shortwave radiation, while the net long wave radiation was negative and dominated the net all-wave radiation balance at the surface. The observed crystal habits of the frost flowers were long needles, betraying their origin from the vapour phase at temperatures between -20°C and -30°C. After a night of growth, frost flowers decayed associated with increased solar radiation, a net surface radiation balance of 0 W m-2, increased air and surface temperatures, increased wind speed, and decreased relative humidity. We hypothesize that these conditions increased vertical mixing, which eroded near-surface water vapour saturation and initiated sublimation. The frost flowers were finally rapidly destroyed by snowfall.

Galley, R.J.; Else, B.G.T.

2015-01-01

119

Evaluation of host susceptibility, pathogen aggressiveness and sporangial survival in soil as factors affecting incidence of potato tuber infection by Phytophthora infestans in Ecuador  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Incidence of potato tuber infection by Phytophthora infestans is low in Ecuador. Factors considered to potentially affect the incidence of tuber infection include pathogen aggressiveness, host resistance, direct suppression from biological and chemical characteristics of soil acting on pathogen propagules, and exclusion resulting from soil structure and high ridging. In this study, we tested the hypothesis that low incidence could be due to reduced pathogen aggressiveness and/or low host susc...

Oyarzu?n, Pedro J.; Anna-Karin Krijger; Garzo?n, Carla D.; Diego Leon; Peter Kromann; Yuen, Jonathan E.; Forbes, Gregory A.

2011-01-01

120

Elevated Bacterial Abundance in Laboratory-Grown and Naturally Occurring Frost Flowers Under Late Winter Conditions  

Science.gov (United States)

Sea ice has been identified as an important microbial habitat, with bacteria and other microbes concentrated in the brine inclusions between ice crystals. Frost flowers, thought to draw brine from underlying sea ice, have not been characterized from a microbial standpoint. To test whether frost flowers serve as an upward vector of bacteria contained within sea ice brines we grew frost flowers in a freezer laboratory (air temperature of -21°C) from saline water spiked with the mesophilic (and thus passive under experimental conditions) bacterium Halomonas pacifica. Salinity of melted samples was measured and bacterial abundance determined by epifluorescent microscopy. Bacterial counts scaled to ice-melt volume averaged 2.82 x 106 ml-1 for frost flowers, compared to 9.47 x 105 ml-1 for underlying ice (3 x higher). Bacterial counts also correlated significantly with salinity (maximum value of 62.5 psu) for frost flowers, brine skim, and ice (df = 17, r = 0.59, p < 0.0001). Segregation coefficients were calculated to describe the efficiency of transport of both cells and salt from the starting solution into frost flowers. From these coefficients an enrichment index was calculated to test for bacterial concentration into frost flowers at a different rate than salt. Analysis with a Student’s T-test (df = 24, t = 0.306, p = .76) indicated that cells and salt were not transported into frost flowers with a significantly different efficiency. To test these findings in the field we then collected frost flowers (and related samples) from new sea ice near Barrow, Alaska in April 2009. Bacterial counts were significantly elevated (again, a 3-fold increase) in natural frost flowers (mean = 2.73 x 105 ml-1) compared to underlying sea ice (mean = 8.46 x 104 cells ml-1). For all field samples collected (frost flowers, underlying brine skim and sea ice, as well as snow), bacterial abundance correlated significantly with salinity (maximum value 124 psu, df = 40, r = 0.60, p < 0.0001). The presence of elevated numbers of bacteria in frost flowers may have implications for the previously observed chemical reactions that take place in them, especially if microbial activity can be shown to occur in this unique low temperature, low water activity microbial habitat.

Bowman, J. S.; Deming, J. W.

2009-12-01

 
 
 
 
121

The geochemical composition of frost flowers in the Alaskan Arctic and their role in mercury deposition  

Science.gov (United States)

Frost flowers are small (centimeters long) intricate crystals that form on newly formed sea ice. They grow from a combination of water vapor deposition and wicking of brine upward from the sea ice surface. Frost flowers are generally two to three times the salinity of seawater and they have a depleted sulfate to sodium ratio that is believed to be caused by the precipitation of mirabilite during their growth. They are a link between the lower atmosphere and sea ice and thus may play a role in the physical and chemical processes that deposit mercury to the Arctic. Reactive halogen radicals oxidize gaseous elemental mercury to reactive gaseous mercury in the lower atmosphere of the Arctic. The resulting reactive gaseous mercury is deposited to snow and ice during spring time Atmospheric Mercury Deposition events (AMDEs). Since frost flowers are halogen rich they are implicated in AMDE chemistry. We collected frost flowers, brine, snow and seawater from the Arctic Ocean north of Barrow, Alaska during three field seasons. Most recently, we participated in the sea ice component of the Ocean-Atmosphere-Sea Ice-Snow (OASIS) campaign in Barrow in 2009. All of our frost flowers yield sulfate to sodium ratios of less than 0.15 which is roughly half that of seawater (0.24). Brine collected from the sea ice surface yields sulfate to sodium ratios close to seawater values. Over an 11 day period all major elements but sulfate decreased in the frost flowers. This suggests that: 1) vapor phase deposition of ice to frost flowers continues long after they initially form, and 2) mirabilite precipitation continues after initial flower growth. Stable oxygen isotope values of the frost flowers became increasingly lower over time with ?18O values evolving from roughly -3‰ to -10‰ over the 11 day period. This further suggests vapor phase deposition onto exposed frost flower surfaces is a continual process following initial flower growth. Brine yielded ?18O values ranging between -0.1‰ and +4‰ suggesting oxygen-18 is preferentially fractionated out of the sea ice crystal lattice more than oxygen-16. Dissolved organic carbon concentrations were below 15 mg/L for all brine and frost flower samples but DOC was detected in seawater (10-11 mg/L). Mercury concentrations in frost flowers range between 25 and 200 ng/L. Some frost flowers were less than eight hours old which suggests that mercury deposition chemistry occurs on the timescale of hours. This geochemical information will be presented in reference to arctic atmospheric chemical processes that promote AMDEs.

Douglas, T. A.; Sturm, M.; Blum, J. D.; Sherman, L. S.; Steffen, A.; Simpson, W. R.

2009-12-01

122

Laboratory studies of the diffuse reflectance spectra of frosts and minerals occurring on astronomical objects  

Science.gov (United States)

A vacuum monochromator was integrated into the system and optics chosen to increase data collection in the infrared spectral region. Using a InSb detector, good reflectance data was obtained to 5.5 micron from a variety of samples including magnesium oxide, barium sulfate, water frost and Bloedite. Magnesium oxide was found to be a poorer reflector than the barium sulfate throughout the visible and near infrared region. The barium sulfate material was shown to be a Lambert reflector in the visible region and over an angular range of 60 deg. Several samples of water frost were prepared and in reflectance measured from 0.3 micron to 5.5 microm. The fine grained frosts were better reflectors than the coarse grained frosts, usually by 20 percent or more, over the entire spectral range. The minerals Bloedite and sulfur were also investigated further.

Glaser, F. M.

1978-01-01

123

Siim Nestor soovitab : Ben Frost ja Alexander Robotnik Eclectical / Siim Nestor  

Index Scriptorium Estoniae

Austraalia muusik ja helilooja Ben Frost projektiga "6 guitars" esinemas festivali Eclectica raames 6. sept. Tartu klubis Rock ja Roll ja itaalia diskor Alexander Robotnik 7. sept. klubis Trehv, esinejatest

Nestor, Siim, 1974-

2007-01-01

124

Frost flowers growing in the Arctic ocean-atmosphere-sea ice-snow interface: 2. Mercury exchange between the atmosphere, snow, and frost flowers  

Science.gov (United States)

Frost flowers are ice crystals that grow on refreezing sea ice leads in Polar Regions by wicking brine from the sea ice surface and accumulating vapor phase condensate. These crystals contain high concentrations of mercury (Hg) and are believed to be a source of reactive halogens, but their role in Hg cycling and impact on the fate of Hg deposited during atmospheric mercury depletion events (AMDEs) are not well understood. We collected frost flowers growing on refreezing sea ice near Barrow, Alaska (U.S.A.) during an AMDE in March 2009 and measured Hg concentrations and Hg stable isotope ratios in these samples to determine the origin of Hg associated with the crystals. We observed decreasing ?199Hg values in the crystals as they grew from new wet frost flowers (mean ?199Hg = 0.77 ± 0.13‰, 1 s.d.) to older dry frost flowers (mean ?199Hg = 0.10 ± 0.05‰, 1 s.d.). Over the same time period, mean Hg concentrations in these samples increased from 131 ± 6 ng/L (1 s.d.) to 180 ± 28 ng/L (1 s.d.). Coupled with a previous study of Hg isotopic fractionation during AMDEs, these results suggest that Hg initially deposited to the local snowpack was subsequently reemitted during photochemical reduction reactions and ultimately accumulated on the frost flowers. As a result of this process, frost flowers may lead to enhanced local retention of Hg deposited during AMDEs and may increase Hg loading to the Arctic Ocean.

Sherman, Laura S.; Blum, Joel D.; Douglas, Thomas A.; Steffen, Alexandra

2012-07-01

125

Trends of spring time frost events and phenological dates in Central Europe  

Science.gov (United States)

Over large parts of the Northern Hemisphere's continents temperature has been increasing during the last century. Particularly minimum temperatures show a more pronounced increase than maximum temperatures. Not only the phenological seasons, but also the potentially plant damaging late frost events are governed by the atmosphere. In case of a rise of minimum temperatures one would expect phenological phases and spring late frost events to occur earlier. In this work the question is elucidated whether plant phenology shifts at a higher or lower rate towards earlier occurrences than potential plant damaging events, like spring late frost events. Frost events based on the last occurrence of daily minimum temperatures below a certain threshold have been moving faster to earlier occurrence dates than phenological phases during the last decades at 50 climate stations in Central Europe. Trend values of frost time series range around -0.2 days/year and of phenological time series are between -0.2 and 0.0 days/year over the period from 1951-1997. `Corylus avellana beginning of pollination' is the only one of the 13 phases considered here with a lower trend value of -0.28 days/year. Early phases are more adapted to below zero temperatures and therefore follow more closely the temperature variability. Later phases seem to have more reason to be concerned about possible late frost events and react more cautiously towards higher spring temperatures and earlier last frost dates. The risk of late frost damage for plants should have been lower during the last decade as compared to the previous decades.

Scheifinger, H.; Menzel, A.; Koch, E.; Peter, Ch.

126

Winter climate controls soil carbon dynamics during summer in boreal forests  

International Nuclear Information System (INIS)

Boreal forests, characterized by distinct winter seasons, store a large proportion of the global terrestrial carbon (C) pool. We studied summer soil C-dynamics in a boreal forest in northern Sweden using a seven-year experimental manipulation of soil frost. We found that winter soil climate conditions play a major role in controlling the dissolution/mineralization of soil organic-C in the following summer season. Intensified soil frost led to significantly higher concentrations of dissolved organic carbon (DOC). Intensified soil frost also led to higher rates of basal heterotrophic CO2 production in surface soil samples. However, frost-induced decline in the in situ soil CO2 concentrations in summer suggests a substantial decline in root and/or plant associated rhizosphere CO2 production, which overrides the effects of increased heterotrophic CO2 production. Thus, colder winter soils, as a result of reduced snow cover, can substantially alter C-dynamics in boreal forests by reducing summer soil CO2 efflux, and increasing DOC losses. (letter)

127

Experimental study on frosting control of mobile air conditioning system with microchannel evaporator  

International Nuclear Information System (INIS)

In this paper, a newly developed frost control system is proposed. System bench tests and vehicle test in wind tunnel have been carried out to explore the anti-frosting performance of automotive air conditioning system with microchannel evaporator. The experimental results are compared with the baseline conventional laminated evaporator system. The test results show that the installation position of temperature sensor can dramatically affect the anti-frosting performance. The clutch switching on/off temperature range of the microchannel evaporator is also experimentally studied. The test results show that, with a proper installation position and on/off temperature range, the system COP can be improved, and meanwhile the panel vents' air off temperature can be reduced, and temperature swing can be reduced. - Highlights: ? The frost control systems were tested with microchannel and laminated evaporators separately. ? The installation position of temperature sensor affects the anti-frosting performance. ? Temperature control range affects the anti-frosting performance. ? The panel vents' air off temperature and swing can be reduced by proper control parameters. ? The system COP can be improved by proper control parameters.

128

Magnetic susceptibility in the prediction of soil attributes in two sugarcane harvesting management systems / Suscetibilidade magnética na predição de atributos do solo em dois sistemas de manejo na colheita de cana de açúcar  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O presente trabalho teve como objetivo investigar o potencial de uso da suscetibilidade magnética (SM) como componente da função de pedotransferência para predição de atributos do solo, sob dois sistemas de manejo na colheita de cana-de-açúcar. Para cada uma das duas áreas de 1 ha (uma com colheita [...] mecanizada de cana crua e outra com colheita manual de cana queimada), foram coletadas 126 amostras de solo que foram submetidas às análises de laboratório, para determinação dos atributos físicos, químicos e mineralógicos do solo e para medição da SM. Os dados foram submetidos à estatística descritiva, calculando-se a média e o coeficiente de variação. Para comparar as médias nos diferentes sistemas de manejo, foi realizado o teste de Tukey, ao nível de significância de 5%. Foram realizados o teste de correlação simples para averiguar a correlação da SM com outros atributos do solo e a regressão múltipla linear a fim de avaliar o quanto a SM contribui para a predição de atributos complexos do solo. Os resultados demonstram que a SM apresentou, em ambos os sistemas de manejo de colheita da cana-de-açúcar, correlação estatística com atributos químicos, físicos e mineralógicos do solo e apresentou potencial para ser utilizada como componente da função de pedotransferência para predição de atributos do Latossolo estudado. Abstract in english This study aimed to investigate the potential use of magnetic susceptibility (MS) as pedotransfer function to predict soil attributes under two sugarcane harvesting management systems. For each area of 1 ha (one with green sugarcane mechanized harvesting and other one with burnt sugarcane manual har [...] vesting), 126 soil samples were collected and subjected to laboratory analysis to determine soil physical, chemical and mineralogical attributes and for measuring of MS. Data were submitted to descriptive statistics by calculating the mean and coefficient of variation. In order to compare the means in the different harvesting management systems it was carried out the Tukey test at a significance level of 5%. In order to investigate the correlation of the MS with other soil properties it was made the correlation test and aiming to assess how the MS contributes to the prediction of soil complex attributes it was made the multiple linear regressions. The results demonstrate that MS showed, in both sugarcane harvesting management systems, statistical correlation with chemical, physical and mineralogical soil attributes and it also showed potential to be used as pedotransfer function to predict attributes of the studied oxisol.

Rafael G., Peluco; José, Marques Júnior; Diego S., Siqueira; Lucas A., Cortez; Gener T., Pereira.

1134-11-01

129

Susceptibility of the eggs of the field slug Deroceras reticulatum to contact with pesticides and substances of biological origin on artificial soil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The toxicity of 14 substances, including a number of pesticides, to the eggs of the pest slug Deroceras reticulatum was determined in laboratory experiments. Eggs were kept in contact with a precisely defined artificial soil to which a range of concentrations of the test substances had been applied. Mortality of the eggs was assessed every 24 h and the median lethal doses (LD50) were determined. The herbicides bromoxynil, ioxynil and pyridate + bromoxynil, the insecticides thiocyclam, diflube...

Iglesias, J.; Castillejo, J.; Ester, A.; Castro, R.; Lombardia, M. J.

2002-01-01

130

The effects of design and operating factors on the frost growth and thermal performance of a flat plate fin-tube heat exchanger under the frosting condition  

International Nuclear Information System (INIS)

An experimental study of the effects of various factors(fin pitch, fin arrangement, air temperature, air humidity, and air velocity) on the frost growth and thermal performance of a fin-tube heat exchanger has been conducted under the frosting condition. It is found that the thermal performance of a heat exchanger is closely related to the blockage ratio of the air flow passages due to the frost growth. The maximum allowable blockage ratio is used to determine the criteria for the optimal operating conditions of a fin-tube heat exchanger. It is also shown that heat transfer rate of heat exchanger with staggered fin arrangement increases about 17% and the time required for heat transfer rate to reach a maximum value becomes longer, compared with those of an inline fin-tube heat exchanger under the frosting condition. The energy transfer resistance between the air and coolant decreases with the increase of inlet air temperature and velocity and with decreasing inlet air humidity

131

Experimental Study on Frost Height of Round Plate Fin-Tube Heat Exchangers for Mobile Heat Pumps  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective of this study was to provide experimental data that could be used to predict frost growth and frost performance of a round plate fin-tube heat exchanger for low temperature heat pumps used in zero emission vehicles under cold weather conditions. In this study, round plate fin-tube heat exchangers were tested with variation of the fin space, air flow rate, relative humidity, and inlet air temperature. Frost height was measured and considered with the boundary layer interruption b...

Dong-Yeon Lee; Moo-Yeon Lee; Yongchan Kim

2012-01-01

132

Germination and seedling frost tolerance differ between the native and invasive range in common ragweed.  

Science.gov (United States)

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. The characterization of differences between populations in native and invasive ranges may improve our understanding of range expansion and adaptation. Here, we investigated germination characteristics of Ambrosia artemisiifolia L., a successful invader in Europe, under a temperature gradient between 5 and 25 °C. Besides rate and speed of germination we determined optimal, minimal and maximal temperature for germination of ten North American and 17 European populations that were sampled along major latitudinal and longitudinal gradients. We furthermore investigated the frost tolerance of seedlings. Germination rate was highest at 15 °C and germination speed was highest at 25 °C. Germination rate, germination speed, frost tolerance of seedlings, and the temperature niche width for germination were significantly higher and broader, respectively, for European populations. This was partly due to a higher seed mass of these populations. Germination traits lacked evidence for adaptation to climatic variables at the point of origin for both provenances. Instead, in the native range, seedling frost tolerance was positively correlated with the risk of frosts which supports the assumption of local adaptation. The increased frost tolerance of European populations may allow germination earlier in the year which may subsequently lead to higher biomass allocation--due to a longer growing period--and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and enhance the existing public health problems associated with this species. PMID:24197990

Leiblein-Wild, Marion Carmen; Kaviani, Rana; Tackenberg, Oliver

2014-03-01

133

Structural Analysis of the Redesigned Ice/Frost Ramp Bracket  

Science.gov (United States)

This paper describes the interim structural analysis of a redesigned Ice/Frost Ramp bracket for the Space Shuttle External Tank (ET). The proposed redesigned bracket consists of mounts for attachment to the ET wall, supports for the electronic/instrument cables and propellant repressurization lines that run along the ET, an upper plate, a lower plate, and complex bolted connections. The eight nominal bolted connections are considered critical in the summarized structural analysis. Each bolted connection contains a bolt, a nut, four washers, and a non-metallic spacer and block that are designed for thermal insulation. A three-dimensional (3D) finite element model of the bracket is developed using solid 10-node tetrahedral elements. The loading provided by the ET Project is used in the analysis. Because of the complexities associated with accurately modeling the bolted connections in the bracket, the analysis is performed using a global/local analysis procedure. The finite element analysis of the bracket identifies one of the eight bolted connections as having high stress concentrations. A local area of the bracket surrounding this bolted connection is extracted from the global model and used as a local model. Within the local model, the various components of the bolted connection are refined, and contact is introduced along the appropriate interfaces determined by the analysts. The deformations from the global model are applied as boundary conditions to the local model. The results from the global/local analysis show that while the stresses in the bolts are well within yield, the spacers fail due to compression. The primary objective of the interim structural analysis is to show concept viability for static thermal testing. The proposed design concept would undergo continued design optimization to address the identified analytical assumptions and concept shortcomings, assuming successful thermal testing.

Phillips, D. R.; Dawicke, D. S.; Gentz, S. J.; Roberts, P. W.; Raju, I. S.

2007-01-01

134

Increasing frost risk associated with advanced citrus flowering dates in Kerman and Shiraz, Iran: 1960-2010  

Science.gov (United States)

Flowering dates and the timing of late season frost are both driven by local ambient temperatures. However, under climatic warming observed over the past century, it remains uncertain how such impacts affect frost risk associated with plant phenophase shifts. Any increase in frost frequency or severity has the potential to damage flowers and their resultant yields and, in more extreme cases, the survival of the plant. An accurate assessment of the relationship between the timing of last frost events and phenological shifts associated with warmer climate is thus imperative. We investigate spring advances in citrus flowering dates (orange, tangerine, sweet lemon, sour lemon and sour orange) for Kerman and Shiraz, Iran from 1960 to 2010. These cities have experienced increases in both T max and T min, advances in peak flowering dates and changes in last frost dates over the study period. Based on daily instrumental climate records, the last frost dates for each year are compared with the peak flowering dates. For both cities, the rate of last frost advance lags behind the phenological advance, thus increasing frost risk. Increased frost risk will likely have considerable direct impacts on crop yields and on the associated capacity to adapt, given future climatic uncertainty.

Fitchett, Jennifer M.; Grab, Stefan W.; Thompson, Dave I.; Roshan, Gholamreza

2014-10-01

135

Parámetros cuantitativos para la evaluación de la suscepti­bilidad a la erosión de suelos tropicales dominicanos / Quantitative parameters for assessing susceptibility to erosion in tropical Dominican soils  

Scientific Electronic Library Online (English)

Full Text Available SciELO Portugal | Language: Spanish Abstract in spanish La capa superficial de los suelos de dife­rentes tipos de bosques tropicales húmedos y secos presentes en la provincia de Peder­nales (República Dominicana), ha sido eva­luada mediante diferentes parámetros rela­cionados con el proceso de erosión: tamaño de partículas, cociente limo/arcilla y un es­ [...] timador de la posibilidad de pérdida de sue-lo. Algunos de los ecosistemas más valiosos están amenazados por talas y quemas y por la implantación de cafetales, de ahí el interés y objetivo de este trabajo, para ver como es­tos usos y manejos afectan a los suelos. Los resultados se presentan comparando los pa­rámetros estudiados en 79 muestras analiza­das según las unidades paisajísticas (bos­ques con y sin usos agropascícolas), así co­mo según las litologías predominantes en las mismas: calizas cristalinas, calizas car­bonatadas sobre alteritas y calizas coralinas. El trabajo muestra por vez primera para esta región, parámetros cuantitativos respecto a procesos edáficos vinculados a la erosión en dicho territorio. Otro dato relativamente no­vedoso es el utilizar la metodología láser para los análisis del tamaño de partículas. Abstract in english The topsoil layers (0-20 cm) of different types of wet and dry tropical forests of the Pedernales province (Dominican Republic), both natural and cultivated, were assessed in terms of different parameters related to the erosion processes: particle size, silt/clay ra­tio, and an estimate of the possi [...] ble soil loss. Some of the soils of the most valuable eco­systems are threatened by the introduction of coffee and hence the interest and objec­tive of this work. We present these data for 79 soil samples according to the corresponding landscape units (forests) along with their dominant lithologies (crystalline limestones, carbon­ated limestones on alterites and coral lime­stones). The novelty of this study is that it uses quantitative variables to describe ed­aphic processes linked to erosion in this re­gion, that had never been quantitatively studied the soils. Another relatively new fact is the methodology uses of the laser for par­ticle size analysis.

A. J., Hernández; C., Vizcayno; S., Alexis; J., Pastor.

2010-01-01

136

Parámetros cuantitativos para la evaluación de la suscepti­bilidad a la erosión de suelos tropicales dominicanos Quantitative parameters for assessing susceptibility to erosion in tropical Dominican soils  

Directory of Open Access Journals (Sweden)

Full Text Available La capa superficial de los suelos de dife­rentes tipos de bosques tropicales húmedos y secos presentes en la provincia de Peder­nales (República Dominicana, ha sido eva­luada mediante diferentes parámetros rela­cionados con el proceso de erosión: tamaño de partículas, cociente limo/arcilla y un es­timador de la posibilidad de pérdida de sue-lo. Algunos de los ecosistemas más valiosos están amenazados por talas y quemas y por la implantación de cafetales, de ahí el interés y objetivo de este trabajo, para ver como es­tos usos y manejos afectan a los suelos. Los resultados se presentan comparando los pa­rámetros estudiados en 79 muestras analiza­das según las unidades paisajísticas (bos­ques con y sin usos agropascícolas, así co­mo según las litologías predominantes en las mismas: calizas cristalinas, calizas car­bonatadas sobre alteritas y calizas coralinas. El trabajo muestra por vez primera para esta región, parámetros cuantitativos respecto a procesos edáficos vinculados a la erosión en dicho territorio. Otro dato relativamente no­vedoso es el utilizar la metodología láser para los análisis del tamaño de partículas.The topsoil layers (0-20 cm of different types of wet and dry tropical forests of the Pedernales province (Dominican Republic, both natural and cultivated, were assessed in terms of different parameters related to the erosion processes: particle size, silt/clay ra­tio, and an estimate of the possible soil loss. Some of the soils of the most valuable eco­systems are threatened by the introduction of coffee and hence the interest and objec­tive of this work. We present these data for 79 soil samples according to the corresponding landscape units (forests along with their dominant lithologies (crystalline limestones, carbon­ated limestones on alterites and coral lime­stones. The novelty of this study is that it uses quantitative variables to describe ed­aphic processes linked to erosion in this re­gion, that had never been quantitatively studied the soils. Another relatively new fact is the methodology uses of the laser for par­ticle size analysis.

A. J. Hernández

2010-01-01

137

Electoral Susceptibility  

CERN Document Server

In the United States electoral system, a candidate is elected indirectly by winning a majority of electoral votes cast by individual states, the election usually being decided by the votes cast by a small number of "swing states" where the two candidates historically have roughly equal probabilities of winning. The effective value of a swing state in deciding the election is determined not only by the number of its electoral votes but by the frequency of its appearance in the set of winning partitions of the electoral college. Since the electoral vote values of swing states are not identical, the presence or absence of a state in a winning partition is generally correlated with the frequency of appearance of other states and, hence, their effective values. We quantify the effective value of states by an {\\sl electoral susceptibility}, $\\chi_j$, the variation of the winning probability with the "cost" of changing the probability of winning state $j$. We study $\\chi_j$ for realistic data accumulated for the 201...

Levine, G C; Cerise, J E

2012-01-01

138

Numerical analysis on the frosting performance of a fin-tube evaporator for a refrigerator  

International Nuclear Information System (INIS)

The objective of this study is to provide numerical and experimental data that can be used to investigate the performance characteristics of a flat plate fin-tube evaporator in household and commercial refrigerators under frosting conditions. Computer simulations with variations of operating conditions such as air inlet temperature, relative humidity, and geometries were performed to find out optimal design parameters of a fin-tube evaporator for household and commercial refrigerators. The tube-by-tube method was used in the simulation and the frost growth model was considered under frosting conditions. The developed analytical model predicted the decreasing rates of heat transfer capacity and air flow rate ratio within ± 10% compared to the experimental results for a refrigerator under real operating conditions. As a result, the frost thickness at 3 .deg. C and 80% is increased 40% than that of -3 .deg. C and 80%, and the frost thickness at 3 .deg. C and 90% is increased 30% than that of 3 .deg. C and 60%. Accordingly, the operating time of the evaporator in the refrigerator was reduced with the increase of the decreasing rate of air flow rate ratio at each condition

139

A frost “buzzsaw” mechanism for erosion of the eastern Southern Alps, New Zealand  

Science.gov (United States)

In the Southern Alps, New Zealand, large gradients in precipitation (scree slopes, cosmogenic radionuclide dating of headwalls, paleo-climate data, and a numerical model of headwall temperature. Currently, active scree slopes occur at a relatively uniform mean elevation (˜ 1450 m) and their distribution is independent of hillslope aspect and rock type, consistent with the notion that frost cracking (which is maximized between - 3 and - 8 °C) may control rockfall erosion. Headwall erosion rates of 0.3 to 0.9 mm year - 1 , measured using in-situ 10Be and 26Al in the Cragieburn Range, confirm that rockfall erosion is active in the late Holocene at rates that roughly balance rock uplift. Models of the predicted depth of frost activity are consistent with the scale of fractures and scree blocks in our field sites. Also, vegetated, paleo-scree slopes are ubiquitous at elevations lower than active scree slopes, consistent with the notion that lower temperatures during the last glacial advance induced pervasive rockfall erosion due to frost cracking. Our modeling suggests temporally-averaged peak frost cracking intensity occurs at 2300 m a.s.l., the approximate elevation of the highest peaks in the central Southern Alps, suggesting that the height of these peaks may be limited by a "frost buzzsaw."

Hales, T. C.; Roering, J. J.

2009-06-01

140

Micromechanics models and innovative sensor technologies to evaluate internal-frost damage of concrete  

Science.gov (United States)

Internal-frost damage is one of the major problems affecting the durability of concrete in cold regions. This paper presents micromechanics models and innovative sensor technologies to study the fundamental mechanisms of frost damage in concrete. The crystallization pressure due to ice nucleation with capillary pores is the primary cause of internal-frost damage of concrete. The crystallization pressure of a cylinder pore was formulated using interface energy balance with thermodynamics equations. The obtained crystallization pressure on the pore wall was input for the fracture simulation with the developed Extended Finite Element Model (XFEM). The XFEM fracture simulation on a homogeneous beam sample with a vertical cylinder pore leads to a straight line. The XFEM simulation was also conducted on the generated digital sample. The simulation results were favorable compared with the middle-notched single edge beam bending specimen due to the open-mode fracture behavior in both cases. An innovative Time-Domain Reflectometry (TDR) sensor was developed to nondestructively monitor the freezing process. The experimental data shows that the TDR sensor signals can detect the freezing degree, an important input parameter to micromechanics models. These studies indicate that the developed micromechanics models and TDR sensor techniques can be used by the practitioners to evaluate internal-frost damage of concrete. Future work will incorporate the TDR sensor measurements into micromechanics models to real-time predict the internal-frost damage process in concrete specimens. The predicted freeze-thaw damage process will be verified with acoustic emission detection.

Dai, Qingli; Yu, Xiong; Ng, Kenny; Zhou, Jun

2011-04-01

 
 
 
 
141

Erodibilidade e suscetibilidade à erosão dos solos de cerrado com plantio de Acacia mangium em Roraima.= Erodibility and susceptibility to erosion of the savannah (cerrado soils planted with Acacia mangium in the State of Roraima.  

Directory of Open Access Journals (Sweden)

Full Text Available Com o objetivo de avaliar erodibilidade e suscetibilidade à erosão de solos sob cerrados e plantios de Acácia mangium no estado de Roraima, foram realizadas visitas nas áreas objeto de estudo para identifi cação geomorfopedológica e feito coleta de solo representativo de 121 perfi s distribuídos nas áreas de plantio de Acacia mangium pertencentes ao projeto Ouro Verde Agrosilvopastoril Ltda. Os perfi s descritos e coletados foram georreferenciados através de GPS e plotados sobre mapas de declividades no software ARCMAPE 8.0 permitindo cruzar os valores de R com a declividade. Foi avaliada as relações do tipo de solo, sua posição na paisagem e suscetibilidade a erosão. Os resultados revelaram que as áreas de estudo estão inseridas em duas unidades geomorfopedológicas distintas: Jacitara/Mucajaí/Santa Cecília (JMSta e Serra da Lua (SL, apresentando suscetibilidade à erosão bem contrastantes; As unidades JMSta apresentam maiores valores de R, inseridas em relevo plano, com declividade entre 1% a 3%, os solos da unidade SL, apresentam menores valores de R e estão posicionados em relevo com declividade entre 3 a 13%, o que a torna mais vulneráveis a erosão; as classes de solos em ordem decrescente em valores de R são: Neossolos (RQo, Argissolos (PAd, Gleissolos (GXbd, Latossolos (LAd, LVd, LVAd, LVA Plintico, Plintossolos (FFCd, concluindo-se então, a necessidade da adoção de práticas simples de conservação de solos, tais como plantio em curva de nível e até terraceamento. = With the objective to evaluate the erodibility and susceptibility to erosion of the cerrado and plantations with Acacia mangium in the State of Roraima, visits to the areas were done for geomorfopedologic identifi cation and collection of soils representative of 121 profi les distributed in the areas pertaining to the plantation of Acacia mangium of the Ouro Verde Agrosilvopastoril Ltda project. The described and collected profiles were geo-referenced through GPS and located on maps of declivities by the software ARCMAPE 8,0 allowing to cross the values of R with the declivity. There were evaluate the relations of the type of soils, its position in the landscape and susceptibility the erosion. The results obtained indicated that the areas studiedy are inserted in two distinct geomorphopedologic units: Jacitara/Mucajai/Santa Cecilia (JMSta and Serra da Lua (SL, and demonstrated distinct susceptibility to erosion; The JMSta units presented the most elevated values of R, inserted in plain relief, with declivity between 1% and 3%. The ground of unit SL, presented small values of R and is located in terrain with declivity between 3% and 13%, which becomes it more vulnerable to erosion; The types of soils decreasing order of values of R are: Neossolos (RQo, Argissolos (PAd, Gleissolos (GXbd, Latossolos (LAd, LVd, LVAd, LVA Plintico, Plintossolos (FFCd. In conclusion, there is the necessity to adopt simple practices of ground conservation, varying from plantation on the curve of level to terracing.

José Frutuoso do Vale Júnior

2009-07-01

142

Susceptibility to shallow landslides of soil in the municipality of Temoaya, Mexico: multicriteria analysis / Susceptibilidad a deslizamientos superficiales de suelo en el Municipio de Temoaya, México: aplicación del análisis multicriterio  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Debido al carácter montañoso del espacio geográfico mexicano, así como del impacto ecológico generado por los cambios de uso de suelo, efectuados particularmente en las últimas décadas, y de la ocurrencia de fenómenos hidrometeorológicos de gran intensidad o frecuencia, la inestabilidad de laderas d [...] esencadenada por precipitación constituye uno de los peligros de mayor impacto en diversas regiones del país, entre ellas el municipio de Temoaya, Estado de México. En este municipio, donde el relieve montañoso formado por depósitos vulcanoclásticos poco consolidados y afallados favorece la inestabilidad, existen 33 procesos de remoción en masa activos, de los cuales treinta -los más importantes-, son deslizamientos de suelo superficiales de tipo traslacional (DSST), un deslizamiento de derrubios y dos caídas de rocas. La ocurrencia de los DSST está controlada por el carácter de los depósitos vulcanoclásticos, específicamente flujos piroclásticos de bloques, cenizas y pómez, los cuales al ser materiales permeables favorecen la infiltración, por lo que si el material subyacente es impermeable o de menor permeabilidad, se presenta una acumulación de agua sobre el contacto litológico subhorizontal que se transforma en un flujo que conduce a la inestabilidad del material sobreyacente. En este trabajo se presenta la aplicación del Método de Análisis Multicriterio para la generación de un mapa de susceptibilidad a deslizamientos de suelo superficiales de tipo traslacional para dicha zona. De acuerdo con el mapa elaborado, el 15% del territorio municipal presenta muy alta susceptibilidad a deslizamientos, mientras que la zona de alta susceptibilidad ocupa el 35% del área en cuestión. El nivel de susceptibilidad medio se concentra en el 30% del territorio, y en el restante 20% de la zona de interés, la susceptibilidad a deslizamientos es baja y muy baja. Abstract in english Owing to the mountainous character of the Mexican terrain, as well as the ecological effects of changes in land use, particularly in recent decades, and the occurrence of severe and frequent hydro-meteorological phenomena, the instability of slopes dislodged by precipitation constitutes a major haza [...] rd in various regions of the country, among them the municipality of Temoaya in the State of Mexico. In this municipality, where the mountainous relief formed by poorly consolidated and faulting volcaniclastic deposits favours instability, there are 33 active processes of mass movement, of which thirty -the most important- are shallow soil translational landslides (SSTL), one is a debris slide and two are rock falls. The occurrence of SSTLs is controlled by the character of the volcaniclastic deposits, specifically pyroclastic flows of blocks, ash and pumice; because these are permeable materials they favour infiltration; if the subjacent material is impermeable or of low permeability, water accumulates on the sub-horizontal lithological contact and transforms into a flow that leads to the instability of the overlying material. A map of susceptibility to SSTLs was generated by means of a multicriteria analysis. According to the map produced, 15% of the municipality is very highly susceptible to landslides, 35% is highly susceptible, 30% shows medium susceptibility, and the remaining 20% has low or very low susceptibility.

Patricia, Flores; Irasema, Alcántara Ayala.

2012-04-01

143

Delineation of frost characteristics on cold walls by using a new formula for psychrometrics demarcation boundary  

International Nuclear Information System (INIS)

In this study, a direct formula that predicts either the frost formation on cold walls is correspondence to psychrometric-subsaturated or supersaturated regions is presented. The developed formula uses the data of the entering air dry-bulb temperature and absolute humidity, and the absolute humidity of the air at saturation corresponding to the coil surface temperature. Cases studies of demarcation criteria for frost formation on evaporator coil using experimental measured data, and on walls of cold storage freezer using measured data from literature are used to validate the formula and it is found that results are completely matches to the graphic plot of the data on the psychrometric chart. In case of cold storage freezers, the result clearly shows that a greater demarcation criteria value indicates frost formation under sever condition that is characterized as snow-like with low density and thermal conductivity.

144

Delineation of frost characteristics on cold walls by using a new formula for psychrometrics demarcation boundary  

Energy Technology Data Exchange (ETDEWEB)

In this study, a direct formula that predicts either the frost formation on cold walls is correspondence to psychrometric-subsaturated or supersaturated regions is presented. The developed formula uses the data of the entering air dry-bulb temperature and absolute humidity, and the absolute humidity of the air at saturation corresponding to the coil surface temperature. Cases studies of demarcation criteria for frost formation on evaporator coil using experimental measured data, and on walls of cold storage freezer using measured data from literature are used to validate the formula and it is found that results are completely matches to the graphic plot of the data on the psychrometric chart. In case of cold storage freezers, the result clearly shows that a greater demarcation criteria value indicates frost formation under sever condition that is characterized as snow-like with low density and thermal conductivity. (author)

Ali, Ahmed Hamza H. [Department of Mechanical Engineering, Faculty of Engineering, Assiut University, Assiut 71516 (Egypt)

2009-06-15

145

Effect of sodium monofluorophosphate treatment on microstructure and frost salt scaling durability of slag cement paste  

International Nuclear Information System (INIS)

Sodium-monofluorophosphate (Na-MFP) is currently in use as a surface applied corrosion inhibitor in the concrete industry. Its basic mechanism is to protect the passive layer of the reinforcement steel against disruption due to carbonation. Carbonation is known as the most detrimental environmental effect on blast furnace slag cement (BFSC) concrete with respect to frost salt scaling. In this paper the effect of Na-MFP on the microstructure and frost salt scaling resistance of carbonated BFSC paste is presented. The results of electron microscopy, mercury intrusion porosimetry (MIP) and X-ray diffraction (XRD) are discussed. It is found that the treatment modifies the microstructure and improves the resistance of carbonated BFSC paste against frost salt attack

146

Void structure of concrete with superabsorbent polymers and its relation to frost resistance of concrete  

DEFF Research Database (Denmark)

Superabsorbent polymers (SAP) can be used to control air void formation in concrete. However, due to surfactant left on suspension polymerized SAP particles during production, they may not only create SAP voids but also entrain extra air. In the present investigation, a method is tested to remove surfactant prior to concrete mixing. The method comprises rinsing of the SAP with ethanol. This effectively removes the surfactant. Freeze-thaw testing of concrete with rinsed and non-rinsed SAP shows that for equal dosages of SAP, the extra air entrained due to surfactant is considerable and can make the difference between poor and satisfactory frost-resistance. Furthermore, the results indicate that voids created directly by SAP protect concrete against frost deterioration just like other air voids; if the concrete contains enough SAP voids, these alone can provide sufficient frost resistance. © 2013 RILEM.

Hasholt, Marianne Tange; Jensen, Ole Mejlhede

2013-01-01

147

North Polar Surfaces of the Uranian Moons: Coated with CO2 Frost?  

Science.gov (United States)

We propose to investigate the near-surface composition of the Uranian moons Ariel, Umbriel, Titania, and Oberon by using the Infrared Array Camera (IRAC) onboard the Spitzer Space Telescope. Previous IRAC observations of these objects in Program 71 (2003 - 2005) indicate that the surfaces of their southern hemispheres are dominated by pure water ice (sub-observer latitudes 7 - 18 degree S). The observations we propose here are of these objects' now observable northern hemispheres (sub-observer latitudes 25 - 33 degree N). Unlike the Program 71 observations, which collected data near the end of southern summer when any seasonal CO2 frost would have migrated to the winter hemisphere, we are proposing to observe these moons at the beginning of northern summer when seasonal CO2 frost should still be present. Therefore, the 2015 - 2016 Cycle 11 opportunity window represents an ideal time frame to search for seasonal CO2 frost on these objects.

Cartwright, Richard; Emery, Joshua; Rivkin, Andy; Trilling, David; Pinilla-Alonso, Noemi

2014-12-01

148

Influence of low temperature and frost duration on Phytophthora alni subsp. alni viability  

Energy Technology Data Exchange (ETDEWEB)

Limits on the survival of P. alni subsp. alni (PAA) due to low temperature can be expected based on previously published laboratory and field studies. This study presents a laboratory experiment to test the influence of low temperature and frost duration on PAA viability. Ten PAA isolates were incubated at different temperatures (-0.1, -2.5, -5.0, -7.5, and -10.0 degree centigrade) and frost durations (0 - 7, 14, 21, and 28 days). A regression analysis confirmed the significant influence of both factors (low temperature and frost duration, and their interaction) on the survival of the pathogen under laboratory conditions. The survival and failure time analysis showed that the survival of the pathogen differs significantly after mild frost (all the isolates tested survived temperatures between -0.1 and -5.0 degree centigrade during the entire testing period) and heavy frost (the pathogen died after 21 days of incubation at -7.5 degree centigrade and after 2 days at -10.0 degree centigrade). Moreover, the viability of the pathogen decreased significantly if the temperature of -5.0 degree centigrade was maintained for at least 1 week and the temperature of -7.5 degree centigrade persisted in laboratory conditions for at least 4 days. The results of the study proved the pathogen to be very sensitive to heavy frost. The low-temperature limits for PAA occur regularly in Central Europe in January. It is probable that these temperatures can reduce PAA populations in diseased black alder stems. The climate change characterised by increases in the lowest minimum winter temperatures in Central Europe (as hypothesised by IPCC) may pose a significant risk for affected alder population in the area. (Author) 21 refs.

Cerny, K.; Filipova, N.; Strnadova, V.

2012-11-01

149

Mineralogia e susceptibilidade magnética dos óxidos de ferro do horizonte B de solos do Estado do Paraná Mineralogy and magnetic susceptibility of iron oxides of B horizon of Paraná state soils  

Directory of Open Access Journals (Sweden)

Full Text Available Os solos tropicais altamente intemperizados tendem a acumular residualmente óxidos de ferro e alumínio. Entre os óxidos e hidróxidos de ferro presentes na fração argila, a goethita (Gt e a hematita (Hm são os mais abundantes e estudados. No entanto, há poucos estudos acerca da identificação e quantificação da maghemita (Mh, um mineral ferrimagnético que está na fração argila dos solos, principalmente naqueles desenvolvidos de rochas máficas. A Mh e a magnetita (Mt são responsáveis pela magnetização espontânea dos solos. Esse atributo mineralógico pode ser medido nos solos e sedimentos pela susceptibilidade magnética por unidade de massa (?BF, cuja magnitude é proporcional à concentração dos minerais ferrimagnéticos e é objeto de estudos em todo mundo. O objetivo deste trabalho foi identificar e quantificar, por ?BF, os minerais ferrimagnéticos de 32 amostras do horizonte B de solos do Estado do Paraná. As formas minerais presentes na fração argila concentrada de óxidos de ferro foram identificadas e semiquantificadas por difratometria de raios-X (DRX. Nessa fração, os minerais mais abundantes são a Gt e a Hm. A Mh foi detectada em 31 amostras por ?BF e em apenas 17 por DRX. Os valores de ?BF variaram de 16 a 8.077 na TFSA, de 12 a 7.953 na fração argila e de 0 a 18.737x10-8 m³ kg-1 na fração argila, após concentração dos óxidos de ferro. A Mh dos solos estudados apresentou valor médio de ?BF em 62.728x10-8m³ kg-1 e sua presença nos difratogramas de raios-X só foi verificada em amostras com valores de ?BF acima de 1.000x10-8m³ kg-1.Highly weathered tropical soils tend to accumulate iron and aluminum oxy-hydroxides. Among the iron oxy-hydroxides found in the clay fraction, goethite (Gt and hematite (Hm are the most abundant and studied. A smaller number of investigations have been publish to identify and to quantify maghemite (Mh, a ferrimagnetic mineral present in the clay size fraction of the soils, mainly in those developed from mafic rocks. Maghemite, along with magnetite (Mt is responsible for the spontaneous magnetic behavior of the soils. This mineralogical attribute can be easy measured, in soils and sediments by mass magnetic susceptibility (?LF, which magnitude is proportional to the concentration of ferrimagnetic minerals and it has been object of studies worldwide. The purpose of this research was to identify and quantify, by ?LF, the ferrimagnetic minerals of 32 samples from B-horizons of Paraná state soils. The mineral species present in the iron oxides concentrated clay size fractions were identified and semiquantified by x-rays diffraction (XRD. In this fraction the most abundant minerals are Gt and Hm. Maghemite was detected in 31 samples by ?LF and in only 17 samples by XRD. The ?LF values ranged from 16 to 8.077x10-8m³ kg-1 in the fine earth; from 12 to 7.953x10-8m³ kg-1 in clay fraction and from 0 to 18.737x10-8m³ kg-1 in clay fraction, after concentration of the iron oxides. The Mh of the soils presented an average value of 62.728x10-8m³ kg-1 and their presence in the X-rays diffractograms was only observed in samples with ?LF values above 1.000x10-8m³ kg-1.

Ivan Granemann de Souza Junior

2010-03-01

150

Mineralogia e susceptibilidade magnética dos óxidos de ferro do horizonte B de solos do Estado do Paraná / Mineralogy and magnetic susceptibility of iron oxides of B horizon of Paraná state soils  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os solos tropicais altamente intemperizados tendem a acumular residualmente óxidos de ferro e alumínio. Entre os óxidos e hidróxidos de ferro presentes na fração argila, a goethita (Gt) e a hematita (Hm) são os mais abundantes e estudados. No entanto, há poucos estudos acerca da identificação e quan [...] tificação da maghemita (Mh), um mineral ferrimagnético que está na fração argila dos solos, principalmente naqueles desenvolvidos de rochas máficas. A Mh e a magnetita (Mt) são responsáveis pela magnetização espontânea dos solos. Esse atributo mineralógico pode ser medido nos solos e sedimentos pela susceptibilidade magnética por unidade de massa (?BF), cuja magnitude é proporcional à concentração dos minerais ferrimagnéticos e é objeto de estudos em todo mundo. O objetivo deste trabalho foi identificar e quantificar, por ?BF, os minerais ferrimagnéticos de 32 amostras do horizonte B de solos do Estado do Paraná. As formas minerais presentes na fração argila concentrada de óxidos de ferro foram identificadas e semiquantificadas por difratometria de raios-X (DRX). Nessa fração, os minerais mais abundantes são a Gt e a Hm. A Mh foi detectada em 31 amostras por ?BF e em apenas 17 por DRX. Os valores de ?BF variaram de 16 a 8.077 na TFSA, de 12 a 7.953 na fração argila e de 0 a 18.737x10-8 m³ kg-1 na fração argila, após concentração dos óxidos de ferro. A Mh dos solos estudados apresentou valor médio de ?BF em 62.728x10-8m³ kg-1 e sua presença nos difratogramas de raios-X só foi verificada em amostras com valores de ?BF acima de 1.000x10-8m³ kg-1. Abstract in english Highly weathered tropical soils tend to accumulate iron and aluminum oxy-hydroxides. Among the iron oxy-hydroxides found in the clay fraction, goethite (Gt) and hematite (Hm) are the most abundant and studied. A smaller number of investigations have been publish to identify and to quantify maghemite [...] (Mh), a ferrimagnetic mineral present in the clay size fraction of the soils, mainly in those developed from mafic rocks. Maghemite, along with magnetite (Mt) is responsible for the spontaneous magnetic behavior of the soils. This mineralogical attribute can be easy measured, in soils and sediments by mass magnetic susceptibility (?LF), which magnitude is proportional to the concentration of ferrimagnetic minerals and it has been object of studies worldwide. The purpose of this research was to identify and quantify, by ?LF, the ferrimagnetic minerals of 32 samples from B-horizons of Paraná state soils. The mineral species present in the iron oxides concentrated clay size fractions were identified and semiquantified by x-rays diffraction (XRD). In this fraction the most abundant minerals are Gt and Hm. Maghemite was detected in 31 samples by ?LF and in only 17 samples by XRD. The ?LF values ranged from 16 to 8.077x10-8m³ kg-1 in the fine earth; from 12 to 7.953x10-8m³ kg-1 in clay fraction and from 0 to 18.737x10-8m³ kg-1 in clay fraction, after concentration of the iron oxides. The Mh of the soils presented an average value of 62.728x10-8m³ kg-1 and their presence in the X-rays diffractograms was only observed in samples with ?LF values above 1.000x10-8m³ kg-1.

Ivan Granemann de, Souza Junior; Antonio Carlos Saraiva da, Costa; Cesar Crispim, Vilar; Allan, Hoepers.

2010-03-01

151

Frost flower surface area and chemistry as a function of salinity and temperature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Frost flowers play a role in air-ice exchange in polar regions, contribute to tropospheric halogen chemistry, and affect ice core interpretation. Frost flowers were observed and collected on the Hudson Bay in March 2008. Their specific surface area (SSA) was measured using CH4 adsorption at 77 K. The Brunauer-Emmett-Teller analysis produced SSA values between 63 and 299 cm(2) g(-1) (mean 162 cm(2) g(-1), accuracy and reproducibility 5%). This range is very similar to that of Domine et al. (20...

Obbard, Rachel W.; Roscoe, Howard K.; Wolff, Eric W.; Atkinson, Helen M.

2009-01-01

152

A nano-frost array technique to prepare nanoporous PVDF membranes  

Science.gov (United States)

Frost, the solid deposition of water vapor from humid air, forms on the surface of a solid substrate when its temperature drops below the freezing point of water. In this study, we demonstrate how this natural phenomenon can be applied to develop novel nanoporous materials. The solvent annealing of polyvinylidene fluoride (PVDF) infiltrated into nanopores induced template-directed dewetting thus preparing nanoembossing films. Then, water nanodroplets formed on the cold polymer nanopatterned surfaces following the embossing patterns, similar to dew formation on the ground. Subsequently, the nanodroplets were frozen and then removed by freeze-drying. This nano-frost array technique produced nanoporous PVDF membranes with an average thickness of 250 (+/-48) nm. It was revealed that the nanopatterned surface formed by solvent annealing played an important role in achieving a nano-frost array with an adjustable size. Additionally, the freezing process led to significant changes of the PVDF crystallinity and polymorphism. Our results prove that the nano-frost array technique can be broadly used to design ordered nanoporous structures and provide new prospects in nanomaterial fields.Frost, the solid deposition of water vapor from humid air, forms on the surface of a solid substrate when its temperature drops below the freezing point of water. In this study, we demonstrate how this natural phenomenon can be applied to develop novel nanoporous materials. The solvent annealing of polyvinylidene fluoride (PVDF) infiltrated into nanopores induced template-directed dewetting thus preparing nanoembossing films. Then, water nanodroplets formed on the cold polymer nanopatterned surfaces following the embossing patterns, similar to dew formation on the ground. Subsequently, the nanodroplets were frozen and then removed by freeze-drying. This nano-frost array technique produced nanoporous PVDF membranes with an average thickness of 250 (+/-48) nm. It was revealed that the nanopatterned surface formed by solvent annealing played an important role in achieving a nano-frost array with an adjustable size. Additionally, the freezing process led to significant changes of the PVDF crystallinity and polymorphism. Our results prove that the nano-frost array technique can be broadly used to design ordered nanoporous structures and provide new prospects in nanomaterial fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00951g

Lee, Min Kyung; Lee, Jonghwi

2014-07-01

153

David Sanders. A Divided Poet: Robert Frost, North of Boston, and the Drama of Disappearance.  

Directory of Open Access Journals (Sweden)

Full Text Available David Sanders in his monograph entitled A Divided Poet: Robert Frost, North of Boston, and the Drama of Disappearance (2011 sheds light on the dilemmas, doubts and personal conflicts Frost confronted while composing his poetic collection North of Boston in which some of his most well-known lyrics, such as “Mending Wall,” “After Apple-Picking,” and “The Wood-Pile,” are contained. This book should be considered alongside a number of other publications either in monograph or essay form that app...

Tatiani G. Rapatzikou

2012-03-01

154

The potential importance of frost flowers, recycling on snow, and open leads for Ozone Depletion Events  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present model studies with the one-dimensional model MISTRA to investigate the potential role of frost flowers, recycling on snow, and open leads in the depletion of tropospheric ozone in the Arctic spring. In our model, we assumed frost flower aerosols to be the major source of bromine. We show that a major ozone depletion event can be satisfactorily reproduced only if the recycling on snow of deposited bromine into gas phase bromine is assumed. In the model, this cycling is more efficien...

Piot, M.; Von Glasow, R.

2007-01-01

155

Carbon-Dioxide Frost Settling from Seasonal Outbursts on Mars (Movie)  

Science.gov (United States)

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Frame #1 FRT00004959, Ls 195 Frame #2 FRT000049C2, Ls 196 [figure removed for brevity, see original site] [figure removed for brevity, see original site] Frame #3 FRT00004B45, Ls 199 Frame #4 FRT000059E2, Ls 226 Mars' seasonal caps consist of frozen carbon dioxide mixed with smaller amounts of water ice frost and dust. The different composition of Mars' seasonal caps than Earth's seasonal caps (water-ice snow), plus the lower pressure of the Martian atmosphere, inevitably make springtime recession of the seasonal cap different than the snowmelt that characterizes retreat of Earth's seasonal cap. To monitor Mars' seasonal changes, CRISM repeatedly targets specific regions as Mars' seasons change. Results shown here are evidence that as warming carbon-dioxide ice vaporizes, some is trapped under the ice slab from which pressurized outbursts occur. The released gas expands, cools, and some of it refreezes and falls back to the surface as bright fans. The region shown in this movie, known informally as Manhattan, is located at 86.3 degrees south latitude, 99 degrees east longitude. To represent the content of the spectral images, two versions of the data are shown side-by-side. The left image was constructed from extended visible wavelengths, to look similar to color images from the High Resolution Imaging Science Experiment (HiRISE) camera. The right image is infrared false-color, with red being the reflectance at 1.30 micrometers, green being depth of the water ice absorption centered at 1.5 micrometers, and blue being depth of the carbon dioxide ice absorption centered at 1.435 micrometers. In this color scheme, surfaces with higher water ice content will appear greenish, while bright carbon dioxide ice will appear magenta. Areas covered by dust will appear dark. In both images, north is to the right. The four time steps in the movie were taken at solar longitudes (Ls) ranging from 195 through 226. (Solar longitude is a measure of seasons, where 180 is southern spring equinox and 270 is southern summer solstice.) The first frame (image FRT00004959, Ls 195) shows a number of spots and dark fan-shaped features, with a higher concentration of spots on a slope in the middle of the scene. The dark fans show multiple directions, generally indicating wind coming out of the east. The second frame (image FRT000049C2, Ls 196) was taken just a few days after the prior one and starts to show color variations in the fans. The third frame (image FRT00004B45, Ls 199) records appearance of bright (bluish) fans in addition to the dark fans. The bright fans are slightly more bluish in the false-color image at right, indicating enrichment in carbon dioxide ice. The tails of the dark fans are more greenish, indicated a slight enhancement of water ice. The fourth and final frame (image FRT000059E2, Ls 226) shows distinct bright fans that appear magenta in the false-color image, indicating carbon dioxide ice with little evidence of water ice. However the surrounding surface is greenish, suggesting small amounts of water ice contamination. The tails of the dark fans appear to be more greenish in the infrared than the surrounding ice, suggesting a slight enhancement of the water ice contamination. The difference between the directions of dark and bright fans suggests changes in the wind direction, perhaps as part of a diurnal cycle or pattern. CRISM science team members working with these data believe that they are seeing evidence for a process first proposed based on data from the Thermal Imaging System (THEMIS) instrument on Mars Odyssey. In this hypothesis, sunlight penetrating the ice warms the underling soil and causes carbon dioxide frost to vaporize at its base. At first the gas is trapped under the frost; when it is released, the e

2007-01-01

156

Climate warming and the risk of frost damage to boreal forest trees : identification of critical ecophysiological traits  

Energy Technology Data Exchange (ETDEWEB)

Eco-physiological traits critical to the occurrence of frost damage in trees in the boreal zone were identified. Two computer simulations were used to examine why 1 simulation predicted heavy frost damage as a consequence of climate warming, while another closely related model did not. The 2 models were developed and parametrized to predict the annual cycle of frost hardiness of trees in central Finland. Model{sub 1} was developed for a theoretical generalized tree species. Model{sub 2} was developed and parametrized to predict needle frost hardiness of Scots pine. Four conceptual traits were used to describe the environmental regulation of ontogenetic development during the ontogenetic phases of growth, lignification, rest and quiescence. The cycle of frost hardiness was developed as a 2-step process. Annual ontogenetic development was modelled with air temperature and night length as the driving forces. The rate of frost hardening and dehardening was then modelled as a function of air temperature, night length and the prevailing phase of the annual ontogenetic cycle. The process was carried out in both models by calculating the rate of change of frost hardiness as a first-order dynamic process. Examination of the risk of frost damage was based on mean values rather than the corresponding maxima of needle damage over the 92 cycles examined. The modelling comparison indicated that the response rates of ontogenetic development during quiescence to air temperature is a critical trait for the risk of frost damage following climate warming. It was suggested that determining the form of the non-linear response is crucial to the assessment of climate warming impacts. Results indicated that predictions of the risk of increased frost damage to trees in response to climate warming remain equivocal. It was concluded that further experimental work with a variety of tree species is needed. 57 refs., 1 tab., 7 figs.

Hanninen, H. [Helsinki Univ., Helsinki (Finland). Plant Ecophysiology and Climate Change Group

2006-07-15

157

Frost flowers on young Arctic sea ice: The climatic, chemical, and microbial significance of an emerging ice type  

DEFF Research Database (Denmark)

Ongoing changes in Arctic sea ice are increasing the spatial and temporal range of young sea ice types over which frost flowers can occur, yet the significance of frost flowers to ocean-sea ice-atmosphere exchange processes remains poorly understood. Frost flowers form when moisture from seawater becomes available to a cold atmosphere and surface winds are low, allowing for supersaturation of the near-surface boundary layer. Ice grown in a pond cut in young ice at the mouth of Young Sound, NE Greenland, in March 2012, showed that expanding frost flower clusters began forming as soon as the ice formed. The new ice and frost flowers dramatically changed the radiative and thermal environment. The frost flowers were about 5°C colder than the brine surface, with an approximately linear temperature gradient from their base to their upper tips. Salinity and ?18O values indicated that frost flowers primarily originated from the surface brine skim. Ikaite crystals were observed to form within an hour in both frost flowers and the thin pond ice. Average ikaite concentrations were 1013?µmol?kg?1 in frost flowers and 1061?µmol?kg?1 in the surface slush layer. Chamber flux measurements confirmed an efflux of CO2 at the brine-wetted sea ice surface, in line with expectations from the brine chemistry. Bacteria concentrations generally increased with salinity in frost flowers and the surface slush layer. Bacterial densities and taxa indicated that a selective process occurred at the ice surface and confirmed the general pattern of primary oceanic origin versus negligible atmospheric deposition.

Barber, D.; Ehn, J.

2014-01-01

158

Morning Frost in Trench Dug by Phoenix, Sol 113 (False Color)  

Science.gov (United States)

This image from the Surface Stereo Imager on NASA's Phoenix Mars Lander shows morning frost inside the 'Snow White' trench dug by the lander, in addition to subsurface ice exposed by use of a rasp on the floor of the trench. The camera took this image at about 9 a.m. local solar time during the 113th Martian day of the mission (Sept. 18, 2008). Bright material near and below the four-by-four set of rasp holes in the upper half of the image is water-ice exposed by rasping and scraping in the trench earlier the same morning. Other bright material especially around the edges of the trench, is frost. Earlier in the mission, when the sun stayed above the horizon all night, morning frost was not evident in the trench. This image is presented in false color that enhances the visibility of the frost. The trench is 4 to 5 centimeters (about 2 inches) deep, about 23 centimeters (9 inches) wide. Phoenix landed on a Martian arctic plain on May 25, 2008. The mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is led by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

2008-01-01

159

The asymptotic final size distribution of reducible multitype Reed-Frost processes.  

Science.gov (United States)

The asymptotic final size distribution of a multitype Reed-Frost process, a chain-binomial model for the spread of infection in a finite, closed multitype population, is derived in the case of reducible contact pattern between types. The results are obtained using techniques developed for the irreducible case. PMID:3711737

Scalia-Tomba, G

1986-01-01

160

Selective inverted sink efficiency for spring frost protection in almond orchards northwest of Isfahan, Iran  

Science.gov (United States)

A so-called selective inverted sink (SIS) was validated in frost protection of a 20-ha almond orchard. Daily counts of flower buds were made for two branches of some selected almond trees in every plot to determine frost damage percentage. Temperatures increased due to the SIS system, but there was an average gradient of temperature decrease of about 0.4°C per 100 m with distance from the SIS. The minimum air temperature increased from 0.5 to 2.8°C, with the highest increase closest to the SIS. The percent of frost-damaged flower buds of almond relative to the control plot with distance to the SIS system had its maximum gradient (8% per 100 m ) in 100-200-m distance from the SIS, but this gradient decreased to a minimum (4% per 100 m) in 500-700-m distance from the SIS. The ANOVA and Duncan's multiple-range test of air temperature and frost damage data confirm that the significant influence zone of this local SIS was about 500 m.

Yazdanpanah, H.; Stigter, C. J.

2011-08-01

 
 
 
 
161

Evaluation of frost damage in cement-based materials by a nonlinear elastic wave technique  

Science.gov (United States)

Frost resistance of concrete is a major concern in cold regions. RILEM (International union of laboratories and experts in construction materials, systems and structures) recommendations provide two alternatives for evaluating frost damage by nondestructive evaluation methods for concrete like materials. The first method is based on the ultrasonic pulse velocity measurement, while the second alternative technique is based on the resonant vibration test. In this study, we monitor the frost damage in Portland cement mortar samples with water to cement ratio of 0.5 and aggregate to cement ratio of 3. The samples are completely saturated by water and are frozen for 24 hours at -25°C. The frost damage is monitored after 0, 5, 10, 15 and 20 freezing-thawing cycles by nonlinear impact resonance acoustic spectroscopy (NIRAS). The results obtained are compared with those obtained by resonant vibration tests, the second alternative technique recommended by RILEM. The obtained results show that NIRAS is more sensitive to early stages of damage than the standard resonant vibration tests.

Eiras, J. N.; Kundu, T.; Popovics, J. S.; Monzó, J.; Soriano, L.; Payá, J.

2014-03-01

162

Climatic controls on frost cracking and implications for the evolution of bedrock landscapes  

Science.gov (United States)

In mountainous landscapes the role of periglacial processes in producing sediment is poorly defined, despite evidence of abundant talus slopes. Ice growth in rock has long been recognized as an efficient erosion mechanism, but the effects have not been readily applied to landscape evolution in response to tectonic and climatic forcing. Here, we quantify how and where ice-driven mechanical erosion occurs in cold, bedrock-dominated landscapes using a simple one-dimensional numerical heat flow model. In our model, ice grows by water migration to colder regions in shallow rock by the reduction in chemical potential associated with intermolecular forces between ice and mineral surfaces, a process called segregation ice growth. The depth and intensity of frost cracking is primarily dependent on mean annual temperature (MAT), with positive MAT sites characterized by intense cracking in the top meter of the rock mass and a maximum frost penetration of ˜4 m. In contrast, negative MAT areas have less intense cracking that primarily occurs at depths between 50 and 800 cm. We compare the depth and intensity of frost cracking predicted by our model with measures of the intensity of frost processes determined in three studies: The first measured the timing of rockfall in the Canadian Rockies, Niagara Escarpment, and Japanese Alps; the second analyzed scree deposits in the Southern Alps, New Zealand; and the third documented rockfall frequency in Utah. These natural examples show that rockfalls tend to nucleate at elevations that coincide with zones of intense frost cracking predicted by our model. As such, climatic variations associated with interglacial-glacial cycles may impart a significant influence on the denudation of mountainous landscapes.

Hales, T. C.; Roering, Joshua J.

2007-06-01

163

Developing a phenological model for grapevine to assess future frost risk in Luxembourg  

Science.gov (United States)

Late frost damage represents a significant hazard to grape production in cool climate viticulture regions such as Luxembourg. The main aim of our study is to analyze the frequency of these events for the Luxembourg's winegrowing region in the future. Spring frost injuries on grape may occur when young green parts are exposed to air temperature below 0°C. The potential risk is determined by: (i) minimum air temperature conditions and the (ii) the timing of bud burst. Therefore, we developed and validated a model for budburst of the grapevine (*Vitis vinifera)* cultivar Rivaner, the most grown local variety, based on multi-annual data from 7 different sites across Europe and the US. An advantage of this approach is, that it could be applied to a wide range of climate conditions. Higher spring temperatures were projected for the future and could lead to earlier dates of budburst as well as earlier dates of last frost events in the season. However, so far it is unknown if this will increase or decrease the risk of severe late frost damages for Luxembourg's winegrowing region. To address this question results of 10 regional climate change projections from the FP6 ENSEMBLES project (spatial resolution = 25km; A1B emission scenario) were combined with the new bud burst model. The use of a multi model ensemble of climate change projections allows for a better quantification of the uncertainties. A bias corrections scheme, based on local observations, was applied to the model output. Projected daily minimum air temperatures, up to 2098, were compared to the projected date of bud burst in order to quantify the future frost risk for Luxembourg.

Caffarra, A.; Molitor, D.; Pertot, I.; Sinigoy, P.; Junk, J.

2012-04-01

164

Sensitivity of frost occurrence to temperature variability in the European Alps  

Science.gov (United States)

In this study, we set out to investigate the linkage of frost frequency to monthly mean temperature and its sensitivity to temperature changes. According to other related studies, the linkage between frost frequency and monthly mean temperature is approximated month per month via hyperbolic tangent functions. These models are validated using three validation experiments including split sample tests and temporal cross-validation. As there are quality-checked station data in Austria, whose temporal resolution and length allow for such a validation procedure, the validation experiments are conducted there.After the performance of the empirical models is evaluated and found adequate, the hyperbolic tangent approach is applied to about 500 stations within the so called Greater Alpine region (GAR), which extends from about 4 °E to 18 °E and from 44 °N to 49 °N. Using these models, it is possible to derive the sensitivity of frost frequency for any location for which the annual temperature cycle is known. This strategy is explicitly demonstrated for the Po Plain, where vertical temperature profiles on a monthly base are on hand as well as in Austria, where spatially high resolved maps of monthly mean temperature are available. Moreover, at stations for which long-term homogenised series of monthly mean temperature are available, reconstructions of frost frequency via the empirical models are done, returning to historical periods where no measurements of minimum temperature exist.On the basis of these findings, the impact of a possible future warming can be assessed, which is essential with regard to glaciers, permafrost and avalanches. Reduction in frost might bring positive economic aspects for agriculture, but negative consequences for low level skiing areas. Copyright

Auer, Ingeborg; Matulla, Christoph; Böhm, Reinhard; Ungersböck, Markus; Maugeri, Maurizio; Nanni, Teresa; Pastorelli, Rossella

2005-11-01

165

Laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance  

Directory of Open Access Journals (Sweden)

Full Text Available Chilled mirror hygrometers (CMH are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios (<5 ppm in the upper troposphere and lower stratosphere (UT/LS. Understanding the source of the measurement discrepancies is important for a more accurate and reliable determination of water vapour abundance in this region. We have conducted a laboratory study to investigate the potential interference of gas-phase nitric acid (HNO3 with the measurement of frost point temperature, and consequently the water vapour mixing ratio, determined by CMH under conditions representative of operation in the UT/LS. No detectable interference in the measured frost point temperature was found for HNO3 mixing ratios of up to 4 ppb for exposure times up to 150 min. HNO3 was observed to co-condense on the mirror frost, with the adsorbed mass increasing linearly with time at constant exposure levels. Over the duration of a typical balloon sonde ascent (90–120 min, the maximum accumulated HNO3 amounts were comparable to monolayer coverage of the geometric mirror surface area, which corresponds to only a small fraction of the actual frost layer surface area. This small amount of co-condensed HNO3 is consistent with the observed lack of HNO3 interference in the frost point measurement because the CMH utilizes significant reductions (>10% in surface reflectivity by the condensate to determine H2O.

T. Thornberry

2011-02-01

166

Laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance  

Directory of Open Access Journals (Sweden)

Full Text Available Chilled mirror hygrometers (CMH are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios (<5 ppm in the upper troposphere and lower stratosphere (UT/LS. Understanding the source of the measurement discrepancies is important for a more accurate and reliable determination of water vapour abundance in this region. We have conducted a laboratory study to investigate the potential interference of gas-phase nitric acid (HNO3 with the measurement of frost point temperature, and consequently the water vapour mixing ratio, determined by CMH under conditions representative of operation in the UT/LS. No detectable interference in the measured frost point temperature was found for HNO3 mixing ratios of up to 4 ppb for exposure times up to 150 min. HNO3 was observed to co-condense on the mirror frost, with the adsorbed mass increasing linearly with time at constant exposure levels. Over the duration of a typical balloon sonde ascent (90–120 min, the maximum accumulated HNO3 amounts were comparable to monolayer coverage of the geometric mirror surface area, which corresponds to only a small fraction of the actual frost layer surface area. This small amount of co-condensed HNO3 is consistent with the observed lack of HNO3 interference in the frost point measurement because the CMH utilizes significant reductions (>10% in surface reflectivity by the condensate to determine H2O.

T. Thornberry

2010-08-01

167

Effects of complete deep-soil cultivation on initial forest stand development  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Long-term effects of complete deep-soil cultivation on forest growth and yield were evaluated in an experiment initiated in 1988 on six different sites in Sweden. Complete deep-soil cultivation was compared with less intensive site preparation. Ten years after the start. growth. stand structure. damage and survival were evaluated. Conifer seedling growth and survival on sandy sites, frost-prone sites or both. generally increased following deep-soil cultivation compared to patch scarification....

O?rlander, Go?ran; Nordborg, Fredrik; Gemmel, Per

2002-01-01

168

Microbial communities and activities in alpine and subalpine soils.  

Science.gov (United States)

Soil samples were collected along two slopes (south and north) at subalpine (1500-1900 m, under closed vegetation, up to the forest line) and alpine altitudes (2300-2530, under scattered vegetation, above the forest line) in the Grossglockner mountain area (Austrian central Alps). Soils were analyzed for a number of properties, including physical and chemical soil properties, microbial activity and microbial communities that were investigated using culture-dependent (viable heterotrophic bacteria) and culture-independent methods (phospholipid fatty acid analysis, FISH). Alpine soils were characterized by significantly (Ptemperatures, more frost and ice days and higher precipitation, compared with subalpine soils. Microbial activity (soil dehydrogenase activity) decreased with altitude; however, dehydrogenase activity was better adapted to cold in alpine soils compared with subalpine soils, as shown by the lower apparent optimum temperature for activity (30 vs. 37 degrees C) and the significantly (Ptemperature range. With increasing altitude, i.e. in alpine soils, a significant (Paltitude. PMID:19049494

Margesin, Rosa; Jud, Melanie; Tscherko, Dagmar; Schinner, Franz

2009-02-01

169

The potential importance of frost flowers, recycling on snow, and open leads for Ozone Depletion Events  

Directory of Open Access Journals (Sweden)

Full Text Available We present model studies with the one-dimensional model MISTRA to investigate the potential role of frost flowers, recycling on snow, and open leads in the depletion of tropospheric ozone in the Arctic spring. In our model, we assumed frost flower aerosols to be the major source of bromine. We show that a major ozone depletion event can be satisfactorily reproduced only if the recycling on snow of deposited bromine into gas phase bromine is assumed. In the model, this cycling is more efficient than the bromine explosion process and maintains sufficiently high levels of bromine to deplete ozone down to few nmol mol?1 within four days. We assessed the influence of different surface combinations (open lead/frost flowers on the chemistry in the model. Results showed noticeable modifications affecting the composition of aerosols and the deposition velocities. A model run with a series of coupled frost flower fields and open leads, separated by large areas of snow, showed results comparable with field observations. In addition, we studied the effects of modified temperature of either the frost flower field or the ambient airmass. A warmer frost flower field increases the relative humidity and the aerosol deposition rate. The deposition/re-emission process gains in importance, inducing more reactive bromine in the gas phase, and a stronger ozone depletion. A decrease of 1 K in airmass temperature shows in our model that the aerosol uptake capacities of all gas phase species substantially increases, leading to enhanced uptake of acids from the gas phase. Consequently, the so-called bromine explosion accelerated and O3 mixing ratios decreased. In our model representation, variations in wind speed affected the aerosol source function and influenced the amount of bromine in the atmosphere and thus the ozone depletion strength. Recent studies have suggested the important role of the precipitation of calcium carbonate (CaCO3 out of the brine layer for the possible acidification of the liquid phase by acid uptake. Our investigation showed that this precipitation is a crucial process for the timing of the bromine explosion in aerosols. Nevertheless, model runs with either 50% precipitation or complete precipitation displayed a relatively weak difference in ozone mixing ratios after four simulated days. By considering conditions typical for "Arctic Haze" pollution events at the start of the run we obtained a low pH in frost flower aerosols due to a greater mixing ratio of SO2, and a strong recycling efficiency via large aerosol number concentration. The aerosol acidification during a haze event most likely intensifies the ozone depletion strength and occurrence. The comparison between our modeled deposition on snow and sampled snow at Barrow (Alaska shows that approximately 75% of deposited bromine may be re-emitted into the gas phase as Br2/BrCl. Among several non-halogen fluxes from the snow, model simulations showed that only HONO affects the chemistry. Finally, we investigated the release of Br2 potentially produced by heterogeneous reactions directly on frost flowers. In this case, we obtained unrealistic results of aerosol compositions and deposition rates on snow compared to observations in the Arctic.

M. Piot

2007-04-01

170

The potential importance of frost flowers, recycling on snow, and open leads for ozone depletion events  

Directory of Open Access Journals (Sweden)

Full Text Available We present model studies with the one-dimensional model MISTRA to investigate the potential role of frost flowers, recycling on snow, and open leads in the depletion of tropospheric ozone in the Arctic spring. In our model, we assumed frost flower aerosols to be the major source of bromine. We show that a major ozone depletion event can be satisfactorily reproduced only if the recycling on snow of deposited bromine into gas phase bromine is assumed. In the model, this cycling is more efficient than the bromine explosion process and maintains sufficiently high levels of bromine to deplete ozone down to few nmol mol?1 within four days. We assessed the influence of different surface combinations (open lead/frost flowers on the chemistry in the model. Results showed noticeable modifications affecting the composition of aerosols and the deposition velocities. A model run with a series of coupled frost flower fields and open leads, separated by large areas of snow, showed results comparable with field observations. In addition, we studied the effects of modified temperature of either the frost flower field or the ambient airmass. A warmer frost flower field increases the relative humidity and the aerosol deposition rate. The deposition/re-emission process gains in importance, inducing more reactive bromine in the gas phase, and a stronger ozone depletion. A decrease of 1K in airmass temperature shows in our model that the aerosol uptake capacities of all gas phase species substantially increases, leading to enhanced uptake of acids from the gas phase. Consequently, the so-called bromine explosion accelerated and O3 mixing ratios decreased. In our model representation, variations in wind speed affected the aerosol source function and influenced the amount of bromine in the atmosphere and thus the ozone depletion strength. Recent studies have suggested the important role of the precipitation of calcium carbonate (CaCO3 out of the brine layer for the possible acidification of the liquid phase by acid uptake. Our investigation showed that this precipitation is a crucial process for the timing of the bromine explosion in aerosols. Nevertheless, model runs with either 50% precipitation or complete precipitation displayed a relatively weak difference in ozone mixing ratios after four simulated days. By considering conditions typical for "Arctic Haze" pollution events at the start of the run we obtained a low pH in frost flower aerosols due to a greater mixing ratio of SO2, and a strong recycling efficiency via large aerosol number concentration. The aerosol acidification during a haze event most likely intensifies the ozone depletion strength and occurrence. The comparison between our modeled deposition on snow and sampled snow at Barrow (Alaska shows that approximately 75% of deposited bromine may be re-emitted into the gas phase as Br2/BrCl. Among several non-halogen fluxes from the snow, model simulations showed that only HONO affects the chemistry. Finally, we investigated the release of Br2 potentially produced by heterogeneous reactions directly on frost flowers. In this case, we obtained unrealistic results of aerosol compositions and deposition rates on snow compared to observations in the Arctic.

M. Piot

2008-05-01

171

Effects of Condensate and Initial Formation of Thin Frost Layer on Evaporator Coil Performance of Room Air-Conditioners  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigated experimentally and theoretically, how condensate and initial formation of a thin frost layer on thesurface of the evaporator affects the evaporator performance of room air-conditioners compared to dry coil conditions. The theoretically obtained results were validated with the measured values in both wet and initial frost formation conditions and a good correlation was found. The results indicated that, at the same range of change in face velocity value, the total condu...

Ali, Ahmed Hamza H.; Ismail, Ibrahim M.

2007-01-01

172

Air void structure and frost resistance : A challenge to Powers’ spacing factor  

DEFF Research Database (Denmark)

This article compiles results from 4 independent laboratory studies. In each study, the same type of concrete is tested at least 10 times, the air void structure being the only variable. For each concrete mix both air void analysis of the hardened concrete and a salt frost scaling test are conducted. Results were not originally presented in a way, which made comparison possible. Here the amount of scaled material is depicted as function of air voids parameters: total air content, specific surface, spacing factor, and total surface area of air voids. The total surface area of air voids is proportional to the product of total air content and specific surface. In all 4 cases, the conclusion is concurrent that the parameter of total surface area of air voids performs equally well or better than the spacing factor when linking air void characteristics to frost resistance (salt frost scaling). This observation is interesting as the parameter of total surface area of air voids normally is not included in air void analysis. The following reason for the finding is suggested: In the air voids conditions are favourable for ice nucleation. When a capillary pore is connected to an air void, ice formation will take place in the air void, being feed from the capillary, but without pressure build-up in the capillary. If the capillary is not connected to an air void, ice formation will take place in the capillary pore, where it can generate substantial pressure. Like this, frost resistance depends on that capillary pores are connected to air voids. The chance that a capillary pore is connected to an air void depends on the total surface area of air voids in the system, not the spacing factor.

Hasholt, Marianne Tange

2014-01-01

173

ASSESSMENT OF CERAMIC TILE FROST RESISTANCE BY MEANS OF THE FREQUENCY INSPECTION METHOD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper presents some results of our experimental analysis of ceramic cladding element frost resistance, particular attention being paid to the application of the frequency inspection method. Three different sets of ceramic tiles of the Ia class to EN 14 411 B standard made by various manufacturers have been analyzed. The ceramic tiles under investigation have been subjected to freeze-thaw-cycle-based degradation in compliance with the relevant ?SN EN ISO 10545-12 standard. Furthermore, ac...

MICHAL MATYSÍK; ZDEN?K CHOBOLA; IVETA PLŠKOVÁ

2011-01-01

174

Penetration of chlorides in hardened concrete during frost salt scaling cycles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sixty samples from three concrete mixes (same components) were prepared and subjected to frost salt scaling cycles. A set of 20 samples from the same mix was tested according to the French standard XP P18-420. Another set was exposed to different chloride concentrations. Different numbers of freeze/thaw cycles were applied to the last set. The mass of scaled-off particles follows a lognormal distribution. Despite high standard deviation, this scaling test enables to separate high resist...

Moral N.; Dangla P.; Dierkens M.; Fen Chong T.; Bouteille S.; Boulanger S.

2010-01-01

175

Flower bud drop and pre-blossom frost damage in apricot (Prunus armeniaca L.)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Apricot (Prunus armeniaca L.) is a species particularly prone to erratic fruit set and flower bud drop has been repeatedly reported in different cultivars and growing conditions. A number of potential causes have been explored, but a clear main cause remains elusive. However, the fact that bud drop can vary depending on the year or site suggests that the process is somehow environmentally influenced. In this work bud development and bud damage have been related with frost temperatures during ...

Julia?n Lagunas, Carmen; Herrero Romero, Mari?a; Rodrigo, Javier

2007-01-01

176

Impact of low temperature on superoxide dismutase (SOD) activity of frost resistant hybrids of potatoes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The isoenzymes changes of superoxide dismutase (SOD) and photosynthetic pigments in frost resistant somatic hybrids of Solanum tuberosum L. and S. commersonii Dun. in vitro culture after low (+6°C) temperature adaptation were investigated. There have discovered interspecific differences of SOD isoenzyme profiles in paternal forms – S. commersonii, S. tuberosum. The hybrids inherited the SOD profiles with 6 isoforms from the recipient S. tuberosum cv. ‘Matilda’, while from donor, a wild...

Vys?niauskiene?, Regina; Janc?ys, Zenonas; Spalinskas, Rapolas

2006-01-01

177

Germination and seedling frost tolerance differ between the native and invasive range in common ragweed  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. The characterization of differences between populations in native and invasive ranges may improve our understanding of range expansion and adaptation. Here, we investigated germination characteristics of Ambrosia artemisiifolia L., a successful invader in Europe, under a temperature gradient between 5 and 25 °C. Besides rate and speed of germination we determi...

Leiblein?wild, Marion Carmen; Kaviani, Rana; Tackenberg, Oliver

2013-01-01

178

Phenology of pear cultivars and resistance of their blossoms to spring frosts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

161 pear cultivars in the collection at Lithuanian institute of Horticulture were investigated. Phenological phases, their beginning and duration, blossom injuries caused by spring frosts and the end of vegetation were evaluated. The latter two characters were estimated according to the scale 0-5: 0 – flowers not injured, 5 – all flowers injured in inflorescence; at the end of vegetation: 0 – leaf fall not started, 5 – all leaves are fallen. It was ascertained that 6.1% of investigate...

Gelvonauskis, Bronislovas; Gelvonauskiene?, Dalia; Banyte?, Irma

2005-01-01

179

On the Relation between Air void system parameters and Salt frost scaling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An attempt to develop a tool based on analysis of the air void system in concrete for an early assessment of salt frost scaling resistance of concrete is presented. Relations between the air void system parameters and scaling are discussed. A new technique based on the accumulated surface area of all air voids is presented. This is a short description of the project. The full report is available from our division and also includes a) a study of the rate of...

Lindmark, Sture

2010-01-01

180

Efek Watermelon Frost Terhadap Penurunan Prostaglandin E2(PGE2) Pada Inflamasi Jaringan Pulpa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pada inflamasi pulpa dapat ditandai dengan peninggian level Prostaglandin E2 (PGEz) bila dibandingkan dengan pulpa normal. Peningkatan level PGEz dapat menyebabkan vasodilatasi pembuluh darah, peningkatan permeabilitas vaskuler, menimbulkan rasa nyeri dan resorpsi tulang. Level PGEz pada kasus-kasus simptomatis lebih tinggi daripada kasus-kasus yang asimptomatis. Watermelon frost telah lama diketahui oleh masyarakat Chinese dapat menurunkan rasa nyeri daninflamasi pada gigi dan rongga mulut. ...

Dennis

2008-01-01

 
 
 
 
181

Simulación del depósito de Escarcha en superficies frías / Simulation of Frost Deposit in Cold Surfaces  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se presenta un código computacional que simula la formación y crecimiento de escarcha sobre una placa mantenida a baja temperatura, por ablimación del vapor de agua de una corriente de aire húmedo que fluye sobre ella. La modelación se basa en ecuaciones de conservación de masa, energía, cantidad de [...] movimiento y especies aplicadas a la escarcha, mezcla aire-vapor e interfase aire-escarcha. El sistema de ecuaciones resulta no lineal acoplado por la fracción volumétrica del hielo, que es calculada iterativamente. El modelo es validado frente a datos experimentales, permitiendo reproducir la evolución de propiedades termofísicas de la escarcha formada y predecir comportamientos para otras condiciones de operación. Los resultados revelan mejor concordancia con datos experimentales que la obtenida por otros autores, y levemente inferior a la del modelo de sobresaturación. Abstract in english The development of a computational code that simulates the formation and frost growth on a cool plate, for the vapor-water ablimation of a humid air current that flows on it, is presented. The numeric modeling is based on the conservation equations of mass, energy, momentum and species applied to th [...] e frost, air-vapor mixtures and air-frost interface. The system of equations is not linear and is coupled by the ice volumetric fraction which is calculated by iteration. The model is validated by comparing the numerical results with experimental data, reproducing the thermophysical properties evolution of the frost formed and predicting the behavior for other operating conditions. The results reveal better agreement with experimental data that those obtained by other authors, and slightly inferior to that of the supersaturation model.

Jorge A, Gatica; Vicente A, Pita; Nisio de C, Lobo.

182

Comparison of heat pump performance using fin-and-tube and microchannel heat exchangers under frost conditions  

International Nuclear Information System (INIS)

Vapor compression heat pumps are drawing more attention in energy saving applications. Microchannel heat exchangers can provide higher performance via less core volume and reduce system refrigerant charge, but little is known about their performance in heat pump systems under frosting conditions. In this study, the system performance of a commercial heat pump using microchannel heat exchangers as evaporator is compared with that using conventional finned-tube heat exchangers numerically and experimentally. The microchannel and finned-tube heat pump system models used for comparison of the microchannel and finned-tube evaporator performance under frosting conditions were developed, considering the effect of maldistribution on both refrigerant and air sides. The quasi-steady-state modeling results are in reasonable agreement with the test data under frost conditions. The refrigerant-side maldistribution is found remarkable impact on the microchannel heat pump system performance under the frost conditions. Parametric study on the fan speed and the fin density under frost conditions are conducted as well to figure out the best trade-off in the design of frost tolerant evaporators. (author)

183

Anthocyanins and glutathione S-transferase activities in response to low temperature and frost hardening in Vaccinium myrtillus (L.).  

Science.gov (United States)

Anthocyanin (Acy) contents and GST activities of bilberry (Vaccinium myrtillus L.) were investigated in two experiments conducted in June (Exp. I: active growth) and in August September (Exp. II: beginning of frost hardening) in Northern Finland (65 degrees N). Bilberry plants were subjected to +2 degrees C and +18 degrees C in Exp. I or +5/0 degrees C (day/night) and +18/+13 degrees C (day/night) in Exp. II. GST activities were assessed using either 1-chloro-2,4-dinitrobenzene (CDNB) or trans-cinnamic acid (tCA) as substrates. We found temperature to have no effect on Acy during either active growth or frost hardening. Acy increased several-fold from active growth to the beginning of frost hardening, but no increment was observed during the development of frost hardening. This suggests a role of Acy in photoprotection at low temperatures rather than their direct involvement in the development of freezing tolerance. The lack of response of GST activity to frost hardening and to temperature in autumn may indicate an indirect role of GSTs in frost hardening as protective enzymes. GST activity was the same with the two substrates studied (CDNB, tCA), supporting the assumption that GSTs could catalyze reactions with endogenous phenylpropanoids. PMID:15384401

Taulavuori, Erja; Tahkokorpi, Marjaana; Taulavuori, Kari; Laine, Kari

2004-08-01

184

Analysis of heat transfer and frost layer formation on a cryogenic tank wall exposed to the humid atmospheric air  

International Nuclear Information System (INIS)

In this paper heat transfer characteristics and frost layer formation are investigated numerically on the surface of a cryogenic oxidizer tank for a liquid propulsion rocket, where a frost layer could be a significant factor in maintaining oxidizer temperature within a required range. Frost formation is modeled by considering mass diffusion of water vapor in the air into the frost layer and various heat transfer modes such as natural and forced convection, latent heat, solar radiation of short wavelength, and ambient radiation of long wavelength. Computational results are first compared with the available measurements and show favorable agreement on thickness and effective thermal conductivity of the frost layer. In the case of the cryogenic tank, a series of parametric studies is presented in order to examine the effects of important parameters such as temperature and wind speed of ambient air, air humidity, and tank wall temperature on the frost layer formation and the amount of heat transfer into the tank. It is found that the heat transfer by solar radiation is significant and also that heat transfer strongly depends on air humidity, ambient air temperature, and wind speed but not tank wall temperature.

185

Mechanism of delayed frost growth on superhydrophobic surfaces with jumping condensates: more than interdrop freezing.  

Science.gov (United States)

Delayed frost growth on superhydrophobic surfaces (SHSs) with jumping condensates has been found by many researchers recently. However, the mechanism of this phenomenon has not been elucidated clearly. In this study, copper SHSs with or without jumping condensates were selected as the substrates for observing condensation icing at a relative humidity (RH) of 60%. The results showed that only SHS with jumping condensates showed delayed condensation icing. Moreover, when such SHSs were placed upward and the surface temperature was held at -10 °C, some discrete frozen drops first appeared on the SHSs. The following icing mainly occurred on these discrete global crystals and then expanded around them until covering the entire surface. Little macroscopic interdrop freezing phenomenon was found. The growth of the frost front is mainly dominated by jumping freezing (the condensed droplets jumped onto the ice crystals and were frozen) or direct vapor-ice deposition. Using microscopy, we found interdrop freezing occurred, in addition to the two mechanisms mentioned above. By placing the SHS downward at -10 °C and intentionally introducing or eliminating tiny dusts, we confirmed that there were no superhydrophobic defects on our SHSs. The discrete frozen drops first appearing on the SHSs were triggered by tiny dusts falling on the surface before or during condensation icing. The key approach in delaying or resisting frost growth on SHSs with jumping condensates is to retard initial ice crystal formation, e.g., eliminating the edge effect and keeping the SHSs clean. PMID:25466489

Hao, Quanyong; Pang, Yichuan; Zhao, Ying; Zhang, Jing; Feng, Jie; Yao, Shuhuai

2014-12-30

186

Decadal predictability of frost days in the MPI-ESM-LR model  

Science.gov (United States)

The number of frost days (days with minimum temperature below 0°C) is a typical index for cold temperature extremes defined by the Joint CCl/CLIVAR/JCOMM Expert Team on Climate Change Detection and Indices (ETCCDI). It's predictability on inter-annual to decadal time scales bears economic and societal relevance, e.g. as basis for energy or agricultural policy planning. As part of the MiKlip initiative for decadal prediction, annually initialised ensemble hindcast experiments with the Max-Planck-Institute Earth System Model in a low resolution configuration (MPI-ESM-LR, T63L47) have been carried out. For a period of 35 years (1961-1995) we analyze the number of frost days per season and grid point on a 5° x 5° longitude-latitude grid for the northern hemisphere stemming from ten/three ensemble member hindcasts produced with two different initialisation strategies. The ensembles are interpreted as probabilistic predictions of historically equiprobable three-category events (below normal, normal, above normal) and as such are compared to frost day counts from HadEx2 and the 20th Century Reanalysis. Prediction skill over climatological forecasts and uninitialised climate projections is assessed for various lead times using the Ranked Probability Skill Score (RPSS).

Kröner, Igor; Kruschke, Tim; Rust, Henning W.; Ulbrich, Uwe

2014-05-01

187

Tier-based approaches for landslide susceptibility assessment in Europe  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the framework of the European Soil Thematic Strategy and the associated proposal of a Framework Directive on the protection and sustainable use of soil, landslides were recognised as a soil threat requiring specific strategies for priority area identification, spatial hazard assessment and management. This contribution outlines the general specifications for nested, Tier-based geographical landslide zonings at small spatial scales to identify priority areas susceptible to landslides (Tier ...

Gunther, Andreas; Reichenbach, Paola; Malet, Jean-philippe; Den Eeckhaut, Miet; Hervas, Javier; Dashwood, Claire; Guzzetti, Fausto

2013-01-01

188

Two loci on wheat chromosome 5A regulate the differential cold-dependent expression of the cor14b gene in frost-tolerant and frost-sensitive genotypes.  

Science.gov (United States)

Although cold acclimation in cereals involves the expression of many cold-regulated genes, genetic studies have shown that only very few chromosomal regions carry loci that play an important role in frost tolerance. To investigate the genetic relationship between frost tolerance and the expression of cold-regulated genes, the expression and regulation of the wheat homolog of the barley cold-regulated gene cor14b was studied at various temperatures in frost-sensitive and frost-tolerant wheat genotypes. At 18/15 degrees C (day/night temperatures) frost-tolerant plants accumulated cor14b mRNAs and expressed COR14b proteins, whereas the sensitive plants did not. This result indicates that the threshold temperature for induction of the wheat cor14b homolog is higher in frost-resistant plants, and allowed us to use this polymorphism in a mapping approach. Studies made with chromosome substitution lines showed that the polymorphism for the threshold induction temperature of the wheat cor14b homolog is controlled by a locus(i) located on chromosome 5A of wheat, while the cor14b gene was mapped in Triticum monococcum on the long arm of chromosome 2Am. The analysis of single chromosome recombinant lines derived from a cross between Chinese Spring/Triticum spelta 5A and Chinese Spring/Cheyenne 5A identified two loci with additive effects that are involved in the genetic control of cor14b mRNA accumulation. The first locus was tightly linked to the marker psr911, while the second one was located between the marker Xpsr2021 and Frost resistance 1 (Fr1). PMID:10778737

Vágújfalvi, A; Crosatti, C; Galiba, G; Dubcovsky, J; Cattivelli, L

2000-03-01

189

Genetic Susceptibility to Atherosclerosis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Atherosclerosis is a complex multifocal arterial disease involving interactions of multiple genetic and environmental factors. Advances in techniques of molecular genetics have revealed that genetic ground significantly influences susceptibility to atherosclerotic vascular diseases. Besides further investigations of monogenetic diseases, candidate genes, genetic polymorphisms, and susceptibility loci associated with atherosclerotic diseases have been identified in recent years, and their numb...

Mirjana Bakran; Sanja Kovacic

2012-01-01

190

Experimental Study on Frost Height of Round Plate Fin-Tube Heat Exchangers for Mobile Heat Pumps  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to provide experimental data that could be used to predict frost growth and frost performance of a round plate fin-tube heat exchanger for low temperature heat pumps used in zero emission vehicles under cold weather conditions. In this study, round plate fin-tube heat exchangers were tested with variation of the fin space, air flow rate, relative humidity, and inlet air temperature. Frost height was measured and considered with the boundary layer interruption between fins. Frost height for 8.0 mm of fin space was increased by approximately 91.9% with an increase of relative humidity from 50.0% to 80.0%. The growth rate of frost height at 1.2 m3/min was observed to be 13.0% greater than that at 0.8 m3/min. Finally, the variation of the blockage ratio with fin space would be an important reference for designing advanced heat exchangers that operate under cold weather conditions.

Dong-Yeon Lee

2012-09-01

191

Liquid-infused nanostructured surfaces with extreme anti-ice and anti-frost performance.  

Science.gov (United States)

Ice-repellent coatings can have significant impact on global energy savings and improving safety in many infrastructures, transportation, and cooling systems. Recent efforts for developing ice-phobic surfaces have been mostly devoted to utilizing lotus-leaf-inspired superhydrophobic surfaces, yet these surfaces fail in high-humidity conditions due to water condensation and frost formation and even lead to increased ice adhesion due to a large surface area. We report a radically different type of ice-repellent material based on slippery, liquid-infused porous surfaces (SLIPS), where a stable, ultrasmooth, low-hysteresis lubricant overlayer is maintained by infusing a water-immiscible liquid into a nanostructured surface chemically functionalized to have a high affinity to the infiltrated liquid and lock it in place. We develop a direct fabrication method of SLIPS on industrially relevant metals, particularly aluminum, one of the most widely used lightweight structural materials. We demonstrate that SLIPS-coated Al surfaces not only suppress ice/frost accretion by effectively removing condensed moisture but also exhibit at least an order of magnitude lower ice adhesion than state-of-the-art materials. On the basis of a theoretical analysis followed by extensive icing/deicing experiments, we discuss special advantages of SLIPS as ice-repellent surfaces: highly reduced sliding droplet sizes resulting from the extremely low contact angle hysteresis. We show that our surfaces remain essentially frost-free in which any conventional materials accumulate ice. These results indicate that SLIPS is a promising candidate for developing robust anti-icing materials for broad applications, such as refrigeration, aviation, roofs, wires, outdoor signs, railings, and wind turbines. PMID:22680067

Kim, Philseok; Wong, Tak-Sing; Alvarenga, Jack; Kreder, Michael J; Adorno-Martinez, Wilmer E; Aizenberg, Joanna

2012-08-28

192

Scattering properties of natural snow and frost - Comparison with icy satellite photometry  

Energy Technology Data Exchange (ETDEWEB)

The Hapke (1986) equation is presently fit to ascertain the single-scattering albedo of the icy satellites of Uranus and Neptune and the one-term Henyey-Greenstein particle-phase function g for each of the Middleton and Mungall (1952) goniophotometric data samples. There emerge both very high single-scattering albedos and strongly forward-scattering particle phase functions; while these are in keeping with Mie theory-based theoretical considerations, they contrast with the observed backscattering behavior of icy satellites. It is suggested the icy satellite frost grains are aggregated into particles of complex texture, which produce the unusual backscattering behavior. 26 refs.

Verbiscer, A.J.; Veverka, J. (Cornell Univ., Ithaca, NY (USA))

1990-12-01

193

Scattering properties of natural snow and frost - Comparison with icy satellite photometry  

International Nuclear Information System (INIS)

The Hapke (1986) equation is presently fit to ascertain the single-scattering albedo of the icy satellites of Uranus and Neptune and the one-term Henyey-Greenstein particle-phase function g for each of the Middleton and Mungall (1952) goniophotometric data samples. There emerge both very high single-scattering albedos and strongly forward-scattering particle phase functions; while these are in keeping with Mie theory-based theoretical considerations, they contrast with the observed backscattering behavior of icy satellites. It is suggested the icy satellite frost grains are aggregated into particles of complex texture, which produce the unusual backscattering behavior. 26 refs

194

Scattering properties of natural snow and frost - Comparison with icy satellite photometry  

Science.gov (United States)

The Hapke (1986) equation is presently fit to ascertain the single-scattering albedo of the icy satellites of Uranus and Neptune and the one-term Henyey-Greenstein particle-phase function g for each of the Middleton and Mungall (1952) goniophotometric data samples. There emerge both very high single-scattering albedos and strongly forward-scattering particle phase functions; while these are in keeping with Mie theory-based theoretical considerations, they contrast with the observed backscattering behavior of icy satellites. It is suggested the icy satellite frost grains are aggregated into particles of complex texture, which produce the unusual backscattering behavior.

Verbiscer, Anne J.; Veverka, Joseph

1990-01-01

195

Further laboratory study of the diffuse reflectance spectra of frosts occurring on astronomical objects  

Science.gov (United States)

Oligoclase and bloedite, two mined samples, have been investigated, and the diffuse reflectance spectra are presented. These data are for powdered material, 50 microns to 5 microns size mixture, cooled to 160 K. The reflectivity of the oligoclase sample was also measured at room temperature, about 290 K, and the results at these two temperatures do indicate some tentative differences. A frost of ordinary water was prepared and its spectral reflectance is presented. This result compares reasonably well with measurements made by other investigators.

Glaser, F. M.

1976-01-01

196

Free convection oxygen vaporizer heat transfer as a function of relative humidity and frost buildup  

Science.gov (United States)

A series of free convection heat transfer tests were made to simulate oxygen vaporizer fintube performance as a function of controlled levels of relative humidity. Test runs were made for relative humidity values set at 20, 40, 60 and 80%. Each test started with a bare fintube and continued until approximately steady state conditions were reached. Frost buildup on the aluminum fintubes was tracked by a continuous video of each test. Plots of heat transfer rates measured in these tests provide data for designing the two-phase portions of liquid oxygen vaporizers for varying ambient humidity conditions.

McIntosh, G. E.; Haaf, K. L.; Moyers, J. A.

2014-01-01

197

Determination of E and G Observables in n Photoproduction on the CLAS Frozen Spin Target (FROST)  

Energy Technology Data Exchange (ETDEWEB)

Polarization observables are vital for disentangling overlapping resonances in the baryon spectrum. Extensive data have been collected at Jefferson Lab in Hall B with circularly and linearly polarized tagged photon beam incident on longitudinally polarized protons provided by the Frozen Spin Target (FROST). The focus of the described work is on ? photoproduction, which acts as an "isospin filter", isolating the N*(I = 1/2) resonances. Preliminary results for the double-polarization observables E and G are presented. There are currently no data on these in the world database for ? photoproduction.

Senderovich, Igor [University of Connecticut, Storrs, CT (United States); Morrison, Brian T. [Arizona State University, Tempe, AZ (United States); Dugger, Michael R. [Arizona State University, Tempe, AZ (United States); Ritchie, Barry G. [Arizona State University, Tempe, AZ (United States); Tucker, Ross J. [Arizona State University, Tempe, AZ (United States)

2014-01-01

198

Extreme values in the water rivers flow evolution, caused by extreme variations of precipitation, water frost or karst  

International Nuclear Information System (INIS)

In this work, there are presented special situations occurred in the evolution of the water rivers flow, caused by different factors: extreme variations of precipitation, important volumes of ice stored in thick ice layers, raising of large levels determined by the presence of the ice jams, infiltrations, strong exsurgence from the karstic area. For every situation are presented concrete examples met on some rivers of Romania. The studies led to the specification of the factors that determined these extreme situations. This specification was made quantitatively on the basis of the relations established between these extreme values of the flow and the characteristics of the factors that determined them. Thus, in the case of small rivers from the eastern part of Romania, with areas till 15-20 km2 is presented first the flow regime, characterized through long periods of drought, over 100-50 days per year, on which there are overlapped rare but very strong floods. There are also presented situations when in melt snow periods, of only 10-15 days, are realised water volumes, which represent 70-75% of the annual stock of the flow. This is the direct effect of the excessive continental climate specific to this area. The analysis was materialized through the establishment of the dependence of drought phenomenon moment and duration to the precipitation quantity, taking into consideration the soil humidity before the drought phenomenon occurrence. The characteristics henomenon occurrence. The characteristics of the maximum flow were determined on the basis of precipitation characteristics in the context of their torrential regime, especially in the framework of small hydrographic basins conditions. For illustrating the remarkable diminishing of the water discharge due to the freezing on some rivers from Transylvania and Northern Moldavia, there were first established the sectors the most affected by the frost. In this purpose, there were obtained relations between the maximum thickness of the ice layers and the characteristics of the air temperature. Depending on the thickness of these layers and the time intervals in which they were formed, there were established the water volumes and, implicitly, the water discharges stored in ices. The results demonstrate that the water volumes stored in ices could lead to decreases of the discharges till almost the total frost, even on some large rivers of the country. The ice jams represent a problem analysed in detail in the framework of this work, as well. First, there are presented the most favourable sectors of ice jams forming on some rivers and even on the Danube. The analysis results highlight the producing of levels rising of over 3m, in the case of some inland rivers and of more than 5 m on the Danube, as it has happened in some severe winters of years. Regarding the karst influence upon the surface flow variation, the analysis points out its radical role, namely the total disappearance of some rivers in the underground but also the appearance of some very strong rivers in this kind of areas. The used methods-discharges measurements in characteristic points, the marking with tracers or with hydrological methods-gave the possibility to establish the direction of the ground water flow and, on the whole, the quantitative influence of various karst areas upon the surface flow in some hydrographic basins.(Author)

199

Evaluación de daños por heladas tardías en ensayos de procedencias de pino oregón introducidos en el norte de la Región Andino Patagónica Argentina / Evaluation of damage by late frosts in provenances trials of Douglas-fir introduced in Argentinian North Patagonia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish La susceptibilidad a las heladas tardías de la fuente de semilla actualmente utilizada es una de las principales características adaptativas que limitan la ampliación del área de plantación de pino oregón (Pseudotsuga menziesii (Mirb.) Franco) en la Región Norpatagónica de la Argentina. En dos ensay [...] os de procedencias de esta especie se registró el daño provocado por heladas de primavera de hasta -7º C de mínima absoluta. En ambos ensayos se encontraron diferencias significativas entre los tratamientos. En el ensayo en el que se registraron mínimas más rigurosas pudieron establecerse correlaciones altamente significativas entre el porcentaje de daño por heladas con la longitud (r = 0,86) y altitud (r = - 0,75) del origen de la semilla, y una menor asociación con la altura media de las plantas en vivero (r = 0,55) y la latitud de origen (r = 0,44). Considerando que los orígenes costeros son los de mayor potencial de crecimiento, estos resultados indican que la selección en base a ese único criterio podría producir una selección indirecta de genotipos susceptibles. Finalmente se recomienda la evaluación simultánea de rendimiento y susceptibilidad para extender el cultivo de la especie hacia áreas de mayor riesgo de heladas. Abstract in english The susceptibility to late frost of the seed source used for afforestations at the moment it is one of the main adaptatives characteristic limiting the increase of the planted area of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Argentinien North Patagonia Region. In two provenances trials [...] of this species we registered frost injury caused by absolute minimum temperature of -7º C during spring. In both sites we found significant differences among treatments. We found a strong correlation between the percentage of frost injury and seed source longitude (r = 0.86) and with seed source altitude (r = 0.75) in the trail that registered the most rigorous minimum. In this trial we found also a weaker association with nursery mean heights (r = 0.55) and the origin latitude (r = 0.44). Considering that coastal origins are those of better potential growth, selection based only growth criteria could produce an indirect selection of susceptible genotypes. Finally we recommend the simultaneous evaluation of yield and susceptibility to be able to extend the specie cultivation towards other areas with increased frost risks.

ALEJANDRO, MARTINEZ MEIER; VICTOR, MONDINO; LEONARDO, GALLO.

2005-12-01

200

Heat transfer characteristics of spirally-coiled circular fin-tube heat exchangers operating under frosting conditions  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to investigate the heat transfer characteristics of spirally-coiled circular fin-tube heat exchangers under frosting conditions. The heat transfer rate, pressure drop, frost thickness, and Nusselt number of the heat exchanger were measured and analyzed by varying the fin pitch and number of tube rows under frosting conditions. In addition, the Nusselt number of the spirally-coiled circular fin-tube exchanger was compared with those of flat plate fin-tube heat exchangers with discrete fins. An empirical correlation of the Nusselt number was developed as a function of the Reynolds number, dimensionless fin pitch normalized by the hydraulic diameter, i.e., D{sub h}/F{sub p}, Fourier number, and number of tube rows. The measured Nusselt number was consistent with the predicted value with mean and average deviations of 3.5% and 0.3%, respectively. (author)

Lee, Mooyeon; Kang, Taehyung; Joo, Youngju [Graduate School of Mechanical Engineering, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713 (Korea, Republic of); Kim, Yongchan [Department of Mechanical Engineering, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713 (Korea, Republic of)

2011-01-15

 
 
 
 
201

Effects of fin pitch and array of the frost layer growth on extended surface of a heat exchanger  

International Nuclear Information System (INIS)

This paper presents the effects of the fin array and pitch on the frost layer growth of a heat exchanger. The numerical results are compared with experimental data of a cold plate to validate the present model, and agree well with experimental data within a maximum error of 8%. The characteristics of the frost formation on staggered fin array are somewhat different from those of in-line array. For fin pitch below 10 mm, the frost layer growth of second fin in the staggered array is affected by that of first fin. The heat transfer of single fin deteriorate with decreasing fin pitch regardless of fin array, however, the thermal performance of a heat exchanger, considering increase of heat surface area, becomes better

202

Soil physical properties affecting soil erosion in tropical soils  

International Nuclear Information System (INIS)

The total vegetated land area of the earth is about 11,500 hectare. Of this, about 12% is in South America. Of this, about 14% is degraded area. Water erosion, chemical degradation, wind erosion, and physical degradation have been reported as main types of degradation. In South America water erosion is a major process for soil degradation. Nevertheless, water erosion can be a consequence of degradation of the soil structure, especially the functional attributes of soil pores to transmit and retain water, and to facilitate root growth. Climate, soil and topographic characteristics determine runoff and erosion potential from agricultural lands. The main factors causing soil erosion can be divided into three groups: Energy factors: rainfall erosivity, runoff volume, wind strength, relief, slope angle, slope length; Protection factors: population density, plant cover, amenity value (pressure for use) and land management; and resistance factors: soil erodibility, infiltration capacity and soil management. The degree of soil erosion in a particular climatic zone, with particular soils, land use and socioeconomic conditions, will always result from a combination of the above mentioned factors. It is not easy to isolate a single factor. However, the soil physical properties that determine the soil erosion process, because the deterioration of soil physical properties is manifested through interrelated problems of surface sealing, crusting, soil compaction, poor drainage, impeded root growth, excessive runoff and accelerated erosion. When an unprotected soil surface is exposed to the direct impact of raindrops it can produce different responses: Production of smaller aggregates, dispersed particles, particles in suspension and translocation and deposition of particles. When this has occurred, the material is reorganized at the location into a surface seal. Aggregate breakdown under rainfall depends on soil strength and a certain threshold kinetic energy is needed to start detachment. Studies on necessary kinetic energy to detach one kilogram of sediments by raindrop impact have shown that the minimum energy is required for particles of 0.125 mm. Particles between 0.063 to 0.250 mm are the most vulnerable to detachment. This means that soils with high content of particles into vulnerable range, for example silty loam, loamy, fine sandy, and sandy loam are the most susceptible soils to detachment. Many aspects of soil behaviour in the field such as hydraulic conductivity water retention, soil crusting, soil compaction, and workability are influenced strongly by the primary particles. In tropical soils also a negative relation between structure stability and particles of silt, fine sand and very fine sand has been found, this is attributed to low cohesiveness of these particles. The ability of a structure to persist is known as its stability. There are two principal types of stability: the ability of the soil to retain its structure under the action of water, and the ability of the soil to retain its structure under the action of external mechanical stresses. (e.g. by wheels). Both types of stability are related with susceptibility to erosion

203

CRYOLINK - Permafrost and seasonal frost in Southern Norway: understanding and modelling the atmosphere-ground temperature  

Science.gov (United States)

Recent years have witnessed a growing interest in Arctic and high-mountain regions. Above the natural tree line Norway is characterised by a modern Arctic environment, and the modern southern boundary for Scandinavian permafrost is located in the mountains of Southern Norway. Permafrost and seasonal frost are considered key components of the cryosphere, and the climate-permafrost relation has acquired added importance with the increasing awareness and concern of rising temperatures. CRYOLINK aims at improving knowledge on past and present ground temperatures, seasonal frost, permafrost distribution and related periglacial processes in Southern Norway and adjoining regions of the North Atlantic region (Greenland and Iceland), by addressing the fundamental problem of heat transfer between the atmosphere and the ground surface. Methodologically, the project develops functional thermal offset models linking air temperatures to ground and permafrost temperatures through seasonal surface transfer functions and subsurface thermal properties based on field observations. The project further develops and apply transient heat transfer models in 1D and 2D to address past and future heat transport into the ground. The project ultimately develops regionally distributed models to address the distributions of surface and ground temperatures in space, and annual thaw and freezing depths. This poster presents the borehole monitoring network established in summer 2008 in Southern Norway, and provides first results.

Etzelmueller, B.; Humlum, O.; Isaksen, K.; Schuler, T. V.; Skaugen, T.; Ødegård, R. S.; Farbrot, H.; Hipp, T.; Lilleøren, K. S.

2009-04-01

204

Frost Growth and Densification on a Flat Surface in Laminar Flow with Variable Humidity  

Science.gov (United States)

Experiments are performed concerning frost growth and densification in laminar flow over a flat surface under conditions of constant and variable humidity. The flat plate test specimen is made of aluminum-6031, and has dimensions of 0.3 mx0.3 mx6.35 mm. Results for the first variable humidity case are obtained for a plate temperature of 255.4 K, air velocity of 1.77 m/s, air temperature of 295.1 K, and a relative humidity continuously ranging from 81 to 54%. The second variable humidity test case corresponds to plate temperature of 255.4 K, air velocity of 2.44 m/s, air temperature of 291.8 K, and a relative humidity ranging from 66 to 59%. Results for the constant humidity case are obtained for a plate temperature of 263.7 K, air velocity of 1.7 m/s, air temperature of 295 K, and a relative humidity of 71.6 %. Comparisons of the data with the author's frost model extended to accommodate variable humidity suggest satisfactory agreement between the theory and the data for both constant and variable humidity.

Kandula, M.

2012-01-01

205

Pumping of gaseous helium using argon frosted liquid helium cryo-condensation pumps  

International Nuclear Information System (INIS)

It has been demonstrated in the Neutral Injection Test Bed that the JET neutral injectors are capable of producing 10 s He beams repetitively with a rate of 7 min per shot without a prohibitive pressure rise. This can be achieved without modifications to the JET liquid helium (LHe) cryo-condensation pumps. The He is pumped by cryo-sorption on Ar, which is frosted onto the LHe temperature panels before each pulse. The measured effective pumping speed is about 0.25 times the value for H2. The measurements involved 3 cryo-pumps, 2 of the JET open structure type and one with a conventional type of liquid nitrogen (LN2) cooled baffle. The tests show that the Ar/He coverage ratio and the thickness of the Ar layer seem to be important. The sticking coefficients for He on Ar frost derived for the 3 pumps agree with each other within the errors. 8 refs., 6 figs., 1 tab

206

Performance comparison of air source heat pump with R407C and R22 under frosting and defrosting  

International Nuclear Information System (INIS)

The dynamic performance characteristics of the air source heat pump (ASHP) with refrigerants R22 and R407C during frosting and defrosting are studied. The results show that both refrigerant systems have similar performance characteristics, except that the performance of the R407C system deteriorated faster than that of the R22 system under frosting, and the performance of the R407C system attains its steady state faster than that of the R22 system after defrosting. R407C refrigerant can be used in either existing systems or in new systems that were originally designed for R22

207

Performance comparison of air source heat pump with R407C and R22 under frosting and defrosting  

Energy Technology Data Exchange (ETDEWEB)

The dynamic performance characteristics of the air source heat pump (ASHP) with refrigerants R22 and R407C during frosting and defrosting are studied. The results show that both refrigerant systems have similar performance characteristics, except that the performance of the R407C system deteriorated faster than that of the R22 system under frosting, and the performance of the R407C system attains its steady state faster than that of the R22 system after defrosting. R407C refrigerant can be used in either existing systems or in new systems that were originally designed for R22. (author)

Liu, Zhiqiang; Wang, Hanqing [School of Civil Engineering, Hunan University of Technology, Zhuzhou 412008 (China); Li, Xiaolin; Peng, Wangming [School of Energy Science and Engineering, Central South University, Changsha 410083 (China)

2008-02-15

208

Performance comparison of air source heat pump with R407C and R22 under frosting and defrosting  

Energy Technology Data Exchange (ETDEWEB)

The dynamic performance characteristics of the air source heat pump (ASHP) with refrigerants R22 and R407C during frosting and defrosting are studied. The results show that both refrigerant systems have similar performance characteristics, except that the performance of the R407C system deteriorated faster than that of the R22 system under frosting, and the performance of the R407C system attains its steady state faster than that of the R22 system after defrosting. R407C refrigerant can be used in either existing systems or in new systems that were originally designed for R22.

Liu Zhiqiang [School of Civil Engineering, Hunan University of Technology, Zhuzhou 412008 (China)], E-mail: liuzq@csu.edu.cn; Li Xiaolin [School of Energy Science and Engineering, Central South University, Changsha 410083 (China); Wang Hanqing [School of Civil Engineering, Hunan University of Technology, Zhuzhou 412008 (China); Peng Wangming [School of Energy Science and Engineering, Central South University, Changsha 410083 (China)

2008-02-15

209

An Innovative Application for SMOS: Characterization of Seasonal Soil Freezing  

Science.gov (United States)

Soil freezing and thawing, including the winter-time evolution of soil frost, are important characteristics influencing hydrological and climate processes at the regions of seasonal frost and permafrost, which include major land areas of North America and northern Eurasia. Changes in the seasonal behaviour of soil frost have a major effect on the surface energy balance, as well as on the intensity of CO2 and CH4 fluxes. The monitoring of seasonal frost and the permafrost active layer is currently based mostly on sparse in-situ observations. Some research using satellite observations for global and continuous coverage has been conducted in the past using active and passive microwave data. The European Space Agency's (ESA) SMOS satellite (Soil Moisture and Ocean Salinity) is the first passive instrument using a low microwave frequency band (1.403 - 1.424 GHz) for Earth remote sensing. The output signal of the SMOS payload instrument MIRAS (Microwave Imaging Radiometer with Aperture Synthesis) is highly sensitive to changes in soil permittivity (i.e. soil liquid water content), with relatively low influence of surface vegetation. Due to the instrument's low operating frequency, information on the soil processes can be achieved from deeper layers than from previously available satellite instruments. SMOS sensitivity to changes in soil permittivity and the deeper soil layer monitoring capabilities ensure new possibilities for soil freeze/thaw cycle monitoring. Within the frame of SMOS programme, ESA has initialized several innovation projects to extend the applicability of SMOS data. One such project is SMOS+ Innovation Permafrost, coordinated by the Finnish Meteorological Institute (FMI) with GAMMA Remote Sensing as a Swiss partner. The main objectives of the project are (1) to develop methods and algorithms for detection and monitoring of soil freezing/thawing processes using L-band passive microwave data and (2) to demonstrate the developed methods with soil frost maps derived from SMOS observations representing the whole Northern Hemisphere. To meet these objectives we have applied data from an experimental three-year campaign using the SMOS reference radiometer, ELBARA-II, for monitoring the seasonal behaviour of the L-band emission signature of boreal soil. In addition, we have developed emission models for various soil systems, and collected in situ data from various locations in Finland, Canada and Siberia for use as reference to SMOS observations. The main regional test site is located in Sodankylä, Northern Finland. The site supports numerous in situ observations of soil, snow and atmosphere properties. Results indicate that the event and development of soil freezing can be monitored with SMOS. However, vegetation, land cover and soil type have a significant effect on the soil freezing processes and need to be taken into account. More future work is needed to improve the algorithms from the present experimental demonstration to an operational product.

Rautiainen, Kimmo; Lemmetyinen, Juha; Schwank, Mike; Pulliainen, Jouni; Mätzler, Christian; Kontu, Anna; Wiesmann, Andreas

2013-04-01

210

Soil management practices for sustainable crop production  

International Nuclear Information System (INIS)

In a sustainable system, the soil is viewed as a fragile and living medium that must be protected and nurtured to ensure its long-term productivity and stability. However, due to high demand for food brought about by high population as well as the decline in agricultural lands, the soil is being exploited beyond its limit thus, leading to poor or sick soils. Sound soil management practices in the Philippines is being reviewed. The technologies, including the advantages and disadvantages are hereby presented. This includes proper cropping systems, fertilizer program, soil erosion control and correcting soil acidity. Sound soil management practices which conserve organic matter for long-term sustainability includes addition of compost, maintaining soil cover, increasing aggregates stability, soil tilt and diversity of soil microbial life. A healthy soil is a key component to sustainability as a health soil produce healthy crop plants and have optimum vigor or less susceptible to pests. (author)

211

REDES NEURONALES PARA MODELAR PREDICCIÓN DE HELADAS / Neural networks for modeling frost prediction  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish En este trabajo se desarrollaron modelos basados en redes neuronales del tipo "backpropagation", para predecir la ocurrencia de heladas, a partir de datos meteorológicos de temperatura, humedad relativa, nubosidad, dirección y velocidad del viento. El entrenamiento y la validación de las redes se re [...] alizaron utilizando 24 años de datos meteorológicos correspondientes a la estación de Río Cuarto, Córdoba, Argentina, separados en 10 años como conjunto de datos de entrenamiento y 14 como conjunto de datos de validación. Se construyeron diferentes modelos para evaluar el comportamiento de las redes cuando se usan distintos números de variables de entrada y/o neuronas en la capa oculta y las probabilidades de aciertos en los resultados de predicción para los mismos, al considerar distintas variables de entrada. En los modelos realizados, el porcentaje de días con error de pronóstico fue de 2%, aproximadamente, para 14 años de aplicación; cuando se consideran días de heladas efectivas no pronosticadas los porcentajes oscilan entre un 10% y un 23%, para el mismo período. Los resultados de la simulación muestran el buen desempeño y la pertinencia general de esta metodología en la estimación de fenómenos de comportamiento no lineal como las heladas Abstract in english In this work models based on neural networks of the backpropagation type were developed in order to predict the occurrence of frosts from meteorological data such as temperature, relative humidity, cloudiness and wind direction and speed. The training and the validation of the networks were made on [...] the basis of 24 years of meteorological data corresponding to the Río Cuarto station, Córdoba, Argentina. These data were grouped as follows: 10 years for the training data set and 14 years for the validation data set. Different models were built to evaluate the performance of the networks when different numbers of input variables and/or neurons in the hidden layer are used, and the probabilities of success in the prediction results on considering different input variables. In the models used, the percentage of days with prediction error was 2%, approximately, for the 14 years of application; when effective frosts days are considered the percentage varies between 10 and 23%, for the same period. The simulation results demonstrated the good performance and the relevance of this methodology for the estimation of the behavior of non-linear phenomena like frosts.

Gustavo, Ovando; Mónica, Bocco; Silvina, Sayago.

2005-03-01

212

REDES NEURONALES PARA MODELAR PREDICCIÓN DE HELADAS Neural networks for modeling frost prediction  

Directory of Open Access Journals (Sweden)

Full Text Available En este trabajo se desarrollaron modelos basados en redes neuronales del tipo "backpropagation", para predecir la ocurrencia de heladas, a partir de datos meteorológicos de temperatura, humedad relativa, nubosidad, dirección y velocidad del viento. El entrenamiento y la validación de las redes se realizaron utilizando 24 años de datos meteorológicos correspondientes a la estación de Río Cuarto, Córdoba, Argentina, separados en 10 años como conjunto de datos de entrenamiento y 14 como conjunto de datos de validación. Se construyeron diferentes modelos para evaluar el comportamiento de las redes cuando se usan distintos números de variables de entrada y/o neuronas en la capa oculta y las probabilidades de aciertos en los resultados de predicción para los mismos, al considerar distintas variables de entrada. En los modelos realizados, el porcentaje de días con error de pronóstico fue de 2%, aproximadamente, para 14 años de aplicación; cuando se consideran días de heladas efectivas no pronosticadas los porcentajes oscilan entre un 10% y un 23%, para el mismo período. Los resultados de la simulación muestran el buen desempeño y la pertinencia general de esta metodología en la estimación de fenómenos de comportamiento no lineal como las heladasIn this work models based on neural networks of the backpropagation type were developed in order to predict the occurrence of frosts from meteorological data such as temperature, relative humidity, cloudiness and wind direction and speed. The training and the validation of the networks were made on the basis of 24 years of meteorological data corresponding to the Río Cuarto station, Córdoba, Argentina. These data were grouped as follows: 10 years for the training data set and 14 years for the validation data set. Different models were built to evaluate the performance of the networks when different numbers of input variables and/or neurons in the hidden layer are used, and the probabilities of success in the prediction results on considering different input variables. In the models used, the percentage of days with prediction error was 2%, approximately, for the 14 years of application; when effective frosts days are considered the percentage varies between 10 and 23%, for the same period. The simulation results demonstrated the good performance and the relevance of this methodology for the estimation of the behavior of non-linear phenomena like frosts.

Gustavo Ovando

2005-03-01

213

Enceladus' CO2 Frost comes from Near-Surface Gas Pockets  

Science.gov (United States)

CO2 frost has been detected on the surface of Enceladus [1]. It was noted by Brown et al. [1] that the frost deposits are not likely permanent and that an active replenishment processes for the gas might be necessary. We suggest that the CO2 that forms the frost originates in shallow gas pockets below the surface. These pockets are a consequence of the ocean water circulation hypothesis [2]. They differ from the plume chambers [3] and are a previously unrecognized structure in the near-surface ice. Enceladus’ oceanic circulation is driven by gas bubbles that make seawater buoyant and bring up water, chemicals, and heat from the depths of a warm ocean [2]. The ocean water ascends through the icy crust and, near the surface, it spreads out laterally beneath a relatively thin ice cap, following the pattern of the thermal anomalies identified in Cassini data [4,5]. Topographic recesses on the bottom of the ice cap act as pockets that collect gas. As the ocean water flows horizontally, the gas bubbles in it continue to rise vertically. Rising bubbles reach the pockets and, over time, pop and release gas. The gas pockets can be ruptured by the regular tidally-controlled fissuring of ice in the South Polar Region (Hurford et al. [6]), forming rifts. If a rift reaches a gas pocket, CO2 gas may escape to the surface. The tortuosity and other properties along the escape route will determine if the gas vents as a seep or a jet. If enough gas is vented to form a cloud, some of the gas will freeze on the surface. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. 2006. [2] Matson D. L. et al., Icarus 221, 53-62, 2012. (also see Matson et al. LPS 44 Abstract 1371, 2013). [3] Schmidt J. et al., Nature 451, 685-688, 2008. [4] Spencer J. R. et al., Science 311, 1401-1405, 2006. [5] Howett C. et al., JGR 116, E03003, 2011. [6] Hurford T. A. et al., Nature 447, 292-294, 2007.

Matson, Dennis L.; Johnson, Torrence; Castillo-Rogez, Julie; Davies, Ashley; Lunine, Jonathan; Radebaugh, Jani

214

Clay mineralogy and magnetic susceptibility of Oxisols in geomorphic surfaces  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Studies analyzing the variability of clay minerals and magnetic susceptibility provide data for the delineation of site-specific management areas since many of their attributes are important to agronomy and the environment. This study aimed to evaluate the spatial variability of clay minerals, magne [...] tic susceptibility, adsorbed phosphorus and physical attributes in Oxisols of sandstones in different geomorphic surfaces. For that purpose, soil samples were collected every 25 m along a transect located within the area where the geomorphic surfaces were identified and mapped. The transect occupied the central portion of 500 ha, where it was also sampled for density purposes with one sample per six hectares. Soil samples were collected at a depth of 0.0-0.2 m. The results of the physical, chemical, mineralogical and magnetic susceptibility analyses were subjected to statistical and geostatistical analyses. The nature of the clay minerals and magnetic susceptibility was dependent on the variation of the soil parent material. High values of magnetic susceptibility were associated with the presence of maghemite and magnetite of coarse size. The spatial variability of crystallinity and the content of Fe oxides, as well as magnetic susceptibility, were dependent on the age of the geomorphic surfaces. The youngest surface had greater spatial variability of these attributes. The iron (goethite and hematite) and aluminum (gibbsite) oxides in the youngest geomorphic surface influenced the low values of soil density and high values of total pore volume, micropores and P adsorption. The characterization of the spatial variability of Fe oxides and susceptibility allowed for the delineation of homogeneous areas.

Livia Arantes, Camargo; José, Marques Júnior; Gener Tadeu, Pereira; Angélica Santos Rabelo de Souza, Bahia.

2014-06-01

215

Psychometric Properties of the Frost Multidimensional Perfectionism Scale with Australian Adolescent Girls: Clarification of Multidimensionality and Perfectionist Typology  

Science.gov (United States)

The psychometric properties of the Frost, Marten, Lahart, and Rosenblate Multidimensional Perfectionism Scale (1990) are investigated to determine its usefulness as a measurement of perfectionism with Australian secondary school girls and to find empirical support for the existence of both healthy and unhealthy types of perfectionist students.…

Hawkins, Colleen C.; Watt, Helen M. G.; Sinclair, Kenneth E.

2006-01-01

216

Peripheral capillary nonperfusion and full-field electroretinographic changes in eyes with frosted branch-like appearance retinal vasculitis  

Directory of Open Access Journals (Sweden)

Full Text Available Yoshitsugu Matsui, Hideyuki Tsukitome, Eriko Uchiyama, Yuko Wada, Tatsuya Yagi, Hisashi Matsubara, Mineo KondoDepartment of Ophthalmology, Mie University Graduate School of Medicine, Tsu, JapanAbstract: We report a patient with frosted branch-like appearance retinal vasculitis associated with peripheral capillary nonperfusion and full-field electroretinographic changes. A 62-year-old man presented with sudden bilateral decreased vision accompanied by headaches. His best-corrected visual acuity was 0.01 in both eyes. Fundus examination and fluorescein angiography showed bilateral frosted branch-like appearance retinal vasculitis, and spectral-domain optical coherence tomography showed severe macular edema in both eyes. The cerebrospinal fluid analyses showed an increased lymphocyte count and protein levels. He was treated with systemic corticosteroid therapy, and his best-corrected visual acuity improved to 0.8 OD and 1.0 OS at 6 months after onset. However, fluorescein angiography showed a lack of capillary perfusion in the periphery, and the oscillatory potentials on full-field electroretinography were severely reduced in both eyes. These findings indicated extensive retinal ischemia and inner retinal dysfunction, and that fluorescein angiography and full-field electroretinograms can be useful during follow-up of eyes with frosted branch-like appearance retinal vasculitis.Keywords: frosted branch angiitis, aseptic meningitis, optical coherence tomography, electroretinogram, oscillatory potentials

Matsui Y

2013-01-01

217

Effects of Condensate and Initial Formation of Thin Frost Layer on Evaporator Coil Performance of Room Air-Conditioners  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigated experimentally and theoretically, how condensate and initial formation of a thin frost layer on thesurface of the evaporator affects the evaporator performance of room air-conditioners compared to dry coil conditions. The theoretically obtained results were validated with the measured values in both wet and initial frost formation conditions and a good correlation was found. The results indicated that, at the same range of change in face velocity value, the total conductivity of a dry coil (UA dry is increased by 38.8%. However, when it is combined with an increase in latent heat to the evaporator total cooling capacity ratio value (Qlat/Q of 10.6%, the total conductivity of wet coil (UA wet is 45.4%. These results clearly indicate that the evaporator coil is characterized by higher performance under wet conditions compared to dry coil conditions. The results also show that the total conductivity after initial formation of a thin frost layer (UA Fr has a higher value by about 8.2% than the dry coil condition. Moreover, the degradation in the evaporator coil performance underthin frost with a thickness up to one mm is only about 6.7%.

Ahmed Hamza H. Ali

2007-12-01

218

The European landslide susceptibility map ELSUS 1000 Version 1  

Science.gov (United States)

With the increase in availability of environmental data sets at global and continental scale and the adoption of the Thematic Strategy for Soil Protection in 2006, small scale risk assessments of soil threats received increasing attention in Europe. We focus on landslides and present an approach for landslide susceptibility evaluation at the continental scale (1 km resolution) over the European territory covered by the EU member states and adjacent countries. Different to previous continental and global scale landslide susceptibility studies, we start with collecting more than 102,000 landslides in 22 European countries. These landslides are heterogeneously distributed over Europe, but are indispensable for the evaluation and classification of Pan-European datasets that can be used as spatial predictors for landslide susceptibility, and the validation of respective assessments. We further attempted a subdivision of the European territory into seven different climato-physiographic zones by combining morphometric and climatic data sets for terrain differentiation, and additionally defining coastal areas as a 1km inland from the coastline. Landslide susceptibility modelling was performed for the individual zones involving heuristic spatial multicriteria evaluations, and validated with the inventory data using receiver operating characteristics. The reliability of the resulting susceptibility map ELSUS 1000 Version 1 was examined on an administrative terrain unit level in areas with landslide information. ELSUS 1000 was further evaluated through comparisons with available national and regional landslide susceptibility maps. These evaluations suggest that although the first version of ELSUS 1000 is capable for a correct synoptic assessment of landslide susceptibility in the majority of the area, it needs further improvement in terms of data used. These should also consider differentiated susceptibility evaluations with respect to different landslide types. ELSUS 1000 Version 1 can be downloaded together with auxiliary data from the European Soil Data Centre (ESDAC) hosted at JRC.

Günther, Andreas; Van Den Eeckhaut, Miet; Malet, Jean-Philippe; Reichenbach, Paola; Hervás, Javier

2013-04-01

219

Frost protection for wind energy installations; Frostschutz fuer Windenergieanlagen. Eisfreie Oberflaechen der Natur abgeschaut  

Energy Technology Data Exchange (ETDEWEB)

This article discusses how naidered intural materials can be used to prevent wind energy installations in exposed alpine locations from icing up. The problems encountered with wind turbines in Scandinavia and in the Swiss Alps due to icing-up are discussed. The mechanisms involved in the formation of hoar frost and clear ice on the rotors of the wind turbines are discussed. Techniques and materials for fighting the icing-up of the rotors are examined. Various special 'ice-phobic' coatings for the rotor blades are listed and discussed. These must adhere to the rotor blades but be repellent to ice. Teflon is quoted as being the most tested material. So-called 'anti-freeze' proteins that can be found in fish and insects are also being examined as a possible coating for the rotors.

Siegmann, K.; Meola, G.; Hirayama, M.

2009-07-01

220

Elevated mercury measured in snow and frost flowers near Arctic sea ice leads  

Science.gov (United States)

Elevated mercury concentrations have been reported in arctic coastal snow far from emission sources. The mercury is deposited during mercury depletion events (MDEs), a set of photochemical atmospheric reactions involving reactive halogens. The highest mercury concentrations are clustered near the coast, leading to speculation that sea ice or sea ice leads play a role in MDEs. The nature of this connection is not fully understood. We report mercury concentrations up to 820 ng/L in snow and frost flowers along sea ice leads near Barrow, Alaska. These concentrations are nine times higher than values from nearby coastal snow and are almost half of the mercury maximum contaminant level in United States drinking water. The high values were found only near leads that had convective plumes above open water suggesting that the same processes that produce a supersaturated environment for water vapor near sea ice leads may be instrumental in mercury deposition.

Douglas, T. A.; Sturm, M.; Simpson, W. R.; Brooks, S.; Lindberg, S. E.; Perovich, D. K.

2005-02-01

 
 
 
 
221

Chinese Frost Multidimensional Perfectionism Scale: a validation and prediction of self-esteem and psychological distress.  

Science.gov (United States)

Recent research has shown that perfectionism is an important psychological variable in explaining various disorders. This study evaluated (a) the factor structure and psychometric properties of the Chinese Frost Multidimensional Perfectionism Scale (CFMPS) and (b) the relative predictive power of its subscales for self-esteem and psychological distress, including depressive, anxiety, and stress symptoms. Nine hundred and forty-seven Chinese adolescents from Hong Kong between 13 and 18 years of age participated in the study. Results indicated that five of the original six factors emerged in the factor analysis. The CFMPS and its subscales were found to have satisfactory internal consistencies. Replicating and extending previous findings, the factors "Concern over Mistakes" and "Doubt about Action" accounted for most of the variances of self-esteem and psychological distress. The factor "Organization" might have positive value on psychological health. Possible cultural influence on the development of perfectionism and limitations of the study are discussed. PMID:10576320

Cheng, S K; Chong, G H; Wong, C W

1999-09-01

222

Research on frost formation in air source heat pump at cold-moist conditions in central-south China  

International Nuclear Information System (INIS)

Highlights: ?A dynamic evaporator model is built up. ? The model involves the ratio of the latent heat to sensible heat of wet air. ?A correlation considering deq is shown below to predict frost accumulation: (Mfrv3)/(?deq2) =((Ta)/(Tw) )0.1((v?)/(deq) )0.7(l/(deq) )1.378Xa1.228. ?The changing ratio can characterize the early development of system performance. ?The changing ratio can characterize the early development of frost accumulation. -- Abstract: A dynamic evaporator model of air source heat pump (ASHP), considering the ratio of the latent heat to sensible heat of wet air, is presented to analyze the performance of ASHP under frosting. The performance parameters, such as the heating capacity, COP and the outlet temperature of compressor, are simulated with CYCLEPAD. Then a semi-empirical correlation that predicts frost accumulation on the air-side of fin-tube heat exchanger is developed with dimensionless analysis and also modified by a test conducted under cold-moist conditions in winter. In addition, eight influence factors are considered involving the ambient conditions and structures of heat exchanger, whose effects are analyzed as well. Among them, the equivalent diameter of air flow cross-section in fin-tube deq is especially proposed. Lastly, the relationships between the ratio, the performance parameters and the frost accumulation are discussed in this paper, followed by an evaluation of an optimal defrosting time interval to improve the ASHP’s energy efficiency and operational reliability at cold-moist conditions in central-south China.

223

Chilling and frost tolerance in Miscanthus and Saccharum genotypes bred for cool temperate climates.  

Science.gov (United States)

Miscanthus hybrids are leading candidates for bioenergy feedstocks in mid to high latitudes of North America and Eurasia, due to high productivity associated with the C4 photosynthetic pathway and their tolerance of cooler conditions. However, as C4 plants, they may lack tolerance of chilling conditions (0-10 °C) and frost, particularly when compared with candidate C3 crops at high latitudes. In higher latitudes, cold tolerance is particularly important if the feedstock is to utilize fully the long, early-season days of May and June. Here, leaf gas exchange and fluorescence are used to assess chilling tolerance of photosynthesis in five Miscanthus hybrids bred for cold tolerance, a complex Saccharum hybrid (energycane), and an upland sugarcane variety with some chilling tolerance. The chilling treatment consisted of transferring warm-grown plants (25/20 °C day/night growth temperatures) to chilling (12/5 °C) conditions for 1 week, followed by assessing recovery after return to warm temperatures. Chilling tolerance was also evaluated in outdoor, spring-grown Miscanthus genotypes before and after a cold front that was punctuated by a frost event. Miscanthus×giganteus was found to be the most chilling-tolerant genotype based on its ability to maintain a high net CO2 assimilation rate (A) during chilling, and recover A to a greater degree following a return to warm conditions. This was associated with increasing its capacity for short-term dark-reversible photoprotective processes (?REG) and the proportion of open photosystem II reaction centres (qL) while minimizing photoinactivation (?NF). Similarly, in the field, M.×giganteus exhibited a significantly greater A and pre-dawn F v/F m after the cold front compared with the other chilling-sensitive Miscanthus hybrids. PMID:24642848

Friesen, Patrick C; Peixoto, Murilo M; Busch, Florian A; Johnson, Daniel C; Sage, Rowan F

2014-07-01

224

SHG & WHH - OVERCOMING SUSCEPTIBILITY  

Directory of Open Access Journals (Sweden)

Full Text Available The WHH (Women Headed Households who belong to poor socio-economicstatus, are trapped in the vicious circle of poverty, violence, exploitation and abuses.These families can be stated as especially susceptible group, who are prone todependency, inequality and exploitation. In the absence of the male spouse in the family;the young and adult women have trying hard to cope-up with the society. Whether theinvolvement of the women in the groups has reduced the susceptibility is the prime searchof this study.

A. THOMAS WILLIAM

2013-05-01

225

Simulation of spring snowmelt runoff by considering micro-topography and phase changes in soil layer  

Directory of Open Access Journals (Sweden)

Full Text Available The NICE model was extended to include the effect of the micro-topography in slope and shading characteristics and the phase changes in soil moisture on snow/frost depths and snowmelt runoff by combining the land-surface, the multi-layer runoff, and the groundwater flow models (NICE-SNOW. The model was applied to the upstream regions of shrinking Kushiro Mire in the invasion of alder, where the spring runoff affects greatly the annual sediment and nutrient transports because the spring flood continues in longer time than that in typhoon seasons. The simulation reproduced excellently the observed values of annual river discharge including snowmelt runoff with the greater time-to-peak of runoff than in snow-free period, in addition to snow depth, frost depth, soil temperature, soil moisture, and groundwater level, by conducting the quantitative assessment of goodness-of-fit and parameter sensitivity analysis. We quantified that the mechanism of spring snowmelt runoff is related to changes in micro-topography, soil structure, soil temperature, soil moisture, and groundwater flow. The model shows that the local effect of snow depth and the frost depth disappears in the snowmelt runoff discharge of catchment in the same way as some previous researches though they are very important as water resources of catchment. After the frozen soil restricts the infiltration in the coldest part of winter, the thawed soil increases the pore size in the early spring. The NICE-SNOW could explain the snowmelt flood continues a longer time than that in the typhoon period because some part of meltwater flows as an intermediate flow in the partially-thawed hillslope soil layer. This is also related to the simulation result that more than half of total soil moisture stays unfrozen at some places even in winter periods, which indicates that there is a high degree of spatial heterogeneity of frozen ground.

T. Nakayama

2006-08-01

226

Multi-Model R-Tool for uncertainty assessment in landslides susceptibility analysis  

Science.gov (United States)

The evaluation of landslide susceptibility requires understanding of the spatial distribution of the factors that control slope instability. It is known that the behavior of landslides is difficult to evaluate because of the various factors that trigger mass movements. The methodology used is very diverse, based on statistical methods, probabilistic methods, deterministic methods, empirical methods or a combination of them and the main factors used for landslide susceptibility assessment are composed from basic morphometric parameters, such as slope gradient, curvature, aspect, solar radiation etc. in combination with lithology, land-use/land-cover, soil types or soil properties. The reliability of susceptibility maps is mostly estimated by a comparison with ground truth and visualized as charts and statistical tables and less by maps for landslides susceptibility uncertainty. Due to similarity of inputs required by numerous susceptibility models, we have developed a Multi-Model tool for R, a free software environment for statistical computing and graphics, combines several landslides susceptibility models into one forecast, thereby improving the forecast accuracy even further. The tool uses as inputs all the predisposing factors and generates susceptibility maps for each model; it combines the resulted susceptibility maps in just one and assesses the uncertainty as a function of susceptibility levels from each map. The final results are susceptibility and uncertainty maps as a function of several susceptibility models. The Multi-Model R-Tool was tested in different areas from Romanian Subcarpathians with very good results

Cosmin Sandric, Ionut; Chitu, Zenaida; Jurchescu, Marta; Micu, Mihai

2014-05-01

227

Effect of surface conditions on runoff and soil loss for chernozem soil  

Directory of Open Access Journals (Sweden)

Full Text Available Rainfall simulation tests were conducted to determine the effect of the initial water content and surface micro-relief changes on runoff, and soil loss for chernozem soil. The studies showed that soil loss by wash was mostly affected by the surface micro-relief, whereas soil loss by splash by the initial water content. Runoff amount was less dependent than the soil loss upon the initial surface conditions and was mostly affected by the seal formation. The highest amount of splash and wash suggest that the time of seal formation at the soil surface was most susceptible to soil erosion.

Dębicki R.

2001-03-01

228

Detection of Soil Freeze/thaw Processes with Smos  

Science.gov (United States)

Soil freezing and thawing processes in the arctic region have a significant impact on the climate both regionally and globally. A frozen soil layer stores temporarily large amounts of carbon and methane. The monitoring of seasonal frost and the permafrost active layer is currently based mostly on sparse in-situ observations. Some research using satellite observations for global and continuous coverage has been conducted in the past using active and passive microwave data. However, the main limitation of directly monitoring the soil freezing/thawing processes has been the lack of a dedicated sensor. The European Space Agency's (ESA) SMOS satellite (Soil Moisture and Ocean Salinity), launched November 2009, is the first passive instrument using a low microwave frequency band (1.403 - 1.424 GHz) for Earth observation. The low L-band frequency acquires information on the top layer soil state below the soil surface. With the SMOS satellite, new soil freezing/thawing algorithms can be developed for global soil frost monitoring. The Finnish Meteorological Institute (FMI) together with GAMMA Remote Sensing (Switzerland) have studied the use of the SMOS satellite for detecting and monitoring soil freeze/thaw processes inthe frame of the ESA SMOS+ Innovation initiative. The main test site is located in Sodankylä, Northern Finland. The site supports numerous in-situ observations of soil, snow and atmosphere properties. FMI also operates an official SMOS reference radiometer at the site; the ESA owned, tower-based ELBARA-II instrument. ELBARA-II has continuously measured a site with typical northern latitude mineral soil since October 2009. Based on these measurements and co-incident in situ observations, FMI has developed a soil frost detection algorithm. The algorithm is based on two characteristics found from the annual behavior of the L-band signal; (1) increase in brightness temperature from summer to winter, and (2) decreased brightness temperature polarization difference during winter. The developed algorithm to derive the first daily soil freezing maps based on SMOS of the Northern Hemisphere.. A validation process of the maps is currently under way. This includes comparisons of the derived maps to in-situ reference measurements over selected test sites in Finland, Canada and Siberia, including comparisons over single observation grid cells and larger areas. For the latter, the soil freezing maps over Finland created from SMOS data were compared to distributed frost tube network observations operated by Finnish Environment Institute (the network consists of over 100 observation locations over Finland). Results indicate that the soil freezing development can be observed with SMOS. However, vegetation, land cover and soil type have a significant effect on the soil freezing process and need to be taken into account. The algorithm is being further developed by investigating these effects both experimentally using tower-based observations and by creating novel emission models for the most typical soil types.

Rautiainen, K.; Pulliainen, J. T.; Menard, C.; Ikonen, J.; Lemmetyinen, J.; Kontu, A.; Mätzler, C.; Schwank, M.; Wiesmann, A.; Drusch, M.

2012-12-01

229

QGP susceptibilities from PNJL model  

International Nuclear Information System (INIS)

An improved version of the PNJL model is used to calculate various thermodynamical quantities including Quark Number Susceptibility, Isospin susceptibility, specific heat, speed of sound and conformal measure. Comparison with Lattice data is found to be encouraging. (author)

230

Electron spin susceptibility of superconductors  

International Nuclear Information System (INIS)

The effect of spin polarization due to the Meissner currents on the electron spin susceptibility of a superconductor is studied. This effect accounts for a susceptibility considerably stronger than that of a normal metal. The spin distribution is discussed

231

QGP Susceptibilities from PNJL Model  

CERN Document Server

An improved version of the PNJL model is used to calculate various thermodynamical quantities, {\\it viz.}, quark number susceptibility, isospin susceptibility, specific heat, speed of sound and conformal measure. Comparison with Lattice data is found to be encouraging.

Ghosh, Sanjay K; Mustafa, Munshi G; Ray, Rajarshi

2008-01-01

232

Role of Changes in Cell Fatty Acids Composition in the Increasing of Frost Resistance of Winter Wheat Suspension Culture  

Directory of Open Access Journals (Sweden)

Full Text Available Influences of low temperatures (4 and 8 ° ? on the frost tolerance and fatty acid compositions of cells in a winter wheat suspension culture have been studied. It has been found that treatment of the culture with 4 °C (7 days did not protect cells from subsequent freezing temperature action (-8 °?, 6 h and was not accompanied significant changes in the fatty acid composition. On the contrary, the treatment of the culture with the temperature 8 °C (7 days prevented the death caused by freezing temperature and the content of saturated fatty acids decreased: pentadecanoic acid (by 35,0%, palmitic acid (by 19,9% and stearic acid (by 65,4%, and the content of ?-linolenic acid increased by 94%. That was the cause of the double bond index (DBI increase by 16%. The role of fatty acids composition changes in the process of increasing frost tolerance in plants are discussed.

I.V. Lyubushkina

2013-11-01

233

The characterisation, improvement and modelling aspects of Frost Salt Scaling of Cement-Based Materials with a High Slag Content:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Blast furnace slag cement concrete is used extensively in a number of countries. In comparison with OPC, it is particularly well known for its excellent performance in marine environments. One dis-advantage of slag cement is its vulnerability to scaling under the combined load of freezing-thawing and de-icing salts. The current investigation was triggered by positive observations regard-ing certain grinding agents used in slag cement production to improve frost salt scaling resistance. The in...

Copuroglu, O.

2006-01-01

234

Efficient non-destructive method of control over the frost-resistance of concretes designated for hydraulic engineering structures ????????????? ??????????? ????? ???????? ??????????????? ??????? ???????????????? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available The author considers the problem of control over the frost resistance as the most important characteristic of concretes designated for hydraulic engineering structures. His method is based on the identification of correlation between the frost resistance and the Poisson ratio. The value of the Poisson ratio is measurable through the employment of the ultra-sound method. The proposed methodology contemplates the following sequence of acts. First, the value of the Poisson ratio of air-dried samples of concrete is identified through the employment of the ultrasound method. Thereafter, samples are exposed to cyclic freezing and thawing. Based on the testing results, correlation between the Poisson ratio values and the frost resistance of the concrete is identified. Further, the same ultrasound method is used to find out the values of the Poisson ratio of the hydraulic engineering structures on site to identify the value of the frost resistance of the concrete on the basis of the correlation identified earlier. Mass produced ultrasound testing devices are to be used for the above purposes. They must have screens, and their ultrasound range must fit concretes. Poisson ratio values are identified through the penetration of the ultrasound signal through the thickness of a concrete element under control. Sensors are to be positioned at the angle of 45°, and the time of travel of longitudinal and shear (lateral ultra-sound waves through the thickness of a concrete sample or a concrete element is measured. The time of travel of longitudinal waves is measured on the basis of the value of the first signal, while shear waves are measured on the basis of the phase transition of ultrasound waves. Thereafter, velocities of waves are calculated pursuant to the methodology proposed by the author. It is noteworthy that the accuracy of the proposed method is quite high, and the margin of error does not exceed 3 %.??????????? ???? ?? ????????? ????????????? ?????? ???????????????? ?????????? - ??? ???????????????. ????????? ???????? ? ??????????? ??????? ??????????? ??????????????? ?????? ? ???????????? ???????? ? ?? ???????????. ?????????? ????????????????? ??????????????? ? ???????????? ????????. ??????? ????????????? ???????? ???????????? ??????????? ??????????????? ?????? ??????????? ??????????????? ???????????????? ??????????.

Popov Valeriy Petrovich

2012-08-01

235

Using Synchrotron Radiation-Based Infrared Microspectroscopy to Reveal Microchemical Structure Characterization: Frost Damaged Wheat vs. Normal Wheat  

Directory of Open Access Journals (Sweden)

Full Text Available This study was conducted to compare: (1 protein chemical characteristics, including the amide I and II region, as well as protein secondary structure; and (2 carbohydrate internal structure and functional groups spectral intensities between the frost damaged wheat and normal wheat using synchrotron radiation-based Fourier transform infrared microspectroscopy (SR-FTIRM. Fingerprint regions of specific interest in our study involved protein and carbohydrate functional group band assignments, including protein amide I and II (ca. 1774–1475 cm?1, structural carbohydrates (SCHO, ca. 1498–1176 cm?1, cellulosic compounds (CELC, ca. 1295–1176 cm?1, total carbohydrates (CHO, ca. 1191–906 cm?1 and non-structural carbohydrates (NSCHO, ca. 954–809 cm?1. The results showed that frost did cause variations in spectral profiles in wheat grains. Compared with healthy wheat grains, frost damaged wheat had significantly lower (p < 0.05 spectral intensities in height and area ratios of amide I to II and almost all the spectral parameters of carbohydrate-related functional groups, including SCHO, CHO and NSCHO. Furthermore, the height ratio of protein amide I to the third peak of CHO and the area ratios of protein amide (amide I + II to carbohydrate compounds (CHO and SCHO were also changed (p < 0.05 in damaged wheat grains. It was concluded that the SR-FTIR microspectroscopic technique was able to examine inherent molecular structure features at an ultra-spatial resolution (10 × 10 ?m between different wheat grains samples. The structural characterization of wheat was influenced by climate conditions, such as frost damage, and these structural variations might be a major reason for the decreases in nutritive values, nutrients availability and milling and baking quality in wheat grains.

Xuewei Zhang

2013-08-01

236

Development of Fractal Ultra-Hydrophobic Coating Films to Prevent Water Vapor Dewing and to Delay Frosting  

Science.gov (United States)

Superhydrophobic films fabricated on copper and aluminum surfaces have potential applications to solve water condensation and frosting problems on chilled ceiling system. The rough surfaces of copper foils obtained by solution immersion method exhibit the existence of fractal structures. The hydrophobicity of copper surfaces is enhanced with fractal structures. The relationship between contact angles (CAs) and the fractal dimensions (FDs) for surface roughness of Cu samples with different etching time is investigated. Moisture condensation and frosting experiments on the two kinds of surfaces are conducted in natural environment under different chilling temperatures. During condensation, micro water condensate droplets drift down the surface like dust floating in the air. Several larger condensate droplets about 1-2 mm appear on the substrates after 3 h condensation. This continuous jumping motion of the condensate will be beneficial in delaying frosting. The results demonstrate that dense nanostructures on copper surfaces are superior to loose lattice-like microstructures on aluminum surfaces for preventing the formation of large droplets condensate and in delaying the icing. The large water droplets of 2-3 mm in diameter that would form on a common metal foil are sharply decreased to dozens of microns and small droplets are formed on a modified surface, which will then drift down like a fog.

Quan, Yun-Yun; Jiang, Pei-Guo; Zhang, Li-Zhi

2014-09-01

237

Side-effects of formulations of permethrin and fenvalerate insecticides on frost resistance and field performance of Picea abies seedlings  

Energy Technology Data Exchange (ETDEWEB)

Side-effects of the permethrin formulations Gori 920 and Gori 920 L, the fenvalerate formulation Sumicidin 10 FW and the emulsifier of the Gori formulations were studied in seedlings of Norway spruce [Picea abies (L.) Karst.]. Whole plant treatment with the Gori formulations in early autumn resulted in a 5-10 deg C poorer frost tolerance (TDI) later in the autumn. Moreover, this treatment increased mortality by 30% within 2 yrs of testing in field trials. In contrast, a basal part treatment with the Gori formulations and whole plant treatment with Sumicidin 10 FW containing 10% fenvalerate had no negative effects during 2 yrs of field testing. Late autumn treatment with Gori 920 and Gori 920 L, followed by cold storage for 6 months, revealed poorer frost tolerance (3-4 deg C) in the spring than that in the control. These treatments also reduced leader shoot growth in the first year and increased the frequency of seedlings lacking a dominant leader after 2 yrs by 20-40%. The detrimental agent in Gori 920 L was found to be the emulsifier, ethoxylated nonylphenol, alone and in combination with the dispersal agent, linseed oil. The linseed oil had no significant additional negative effect on frost resistance and growth after the cold storage during the winter. The investigation demonstrates the necessity of testing for possible side-effects before practical use of any commercial pesticide formulation 12 refs, 4 figs, 2 tabs

Kohmann, Ketil [Norwegian Forest Research Inst., Aas (Norway)

1999-10-01

238

24 CFR 3285.404 - Severe climatic conditions.  

Science.gov (United States)

...Section 3285.404 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued...DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED... In frost-susceptible soil locations, ground anchor...

2010-04-01

239

Penetration of chlorides in hardened concrete during frost salt scaling cycles  

Directory of Open Access Journals (Sweden)

Full Text Available Sixty samples from three concrete mixes (same components were prepared and subjected to frost salt scaling cycles. A set of 20 samples from the same mix was tested according to the French standard XP P18-420. Another set was exposed to different chloride concentrations. Different numbers of freeze/thaw cycles were applied to the last set. The mass of scaled-off particles follows a lognormal distribution. Despite high standard deviation, this scaling test enables to separate high resistant from very low resistant concrete. A combined analysis reveals that the scaling and the chloride penetration front are independent from a phenomenological point of view and that the chloride concentration on the exposed surface directly influences the amount of scaled mass according to the typical pessimum effect. These results raise two main questions: is the amount of chloride on the surface solution a direct or indirect parameter and what happens to this pessimum effect if we take into account the scaling test dispersion?

Moral N.

2010-06-01

240

Alate susceptibility in ants.  

Science.gov (United States)

Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

Ho, Eddie K H; Frederickson, Megan E

2014-11-01

 
 
 
 
241

Alate susceptibility in ants  

Science.gov (United States)

Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

Ho, Eddie K H; Frederickson, Megan E

2014-01-01

242

The diagonal Ising susceptibility  

International Nuclear Information System (INIS)

We use the recently derived form factor expansions of the diagonal two-point correlation function of the square Ising model to study the susceptibility for a magnetic field applied only to one diagonal of the square lattice, for the isotropic Ising model. We exactly evaluate the one and two particle contributions ?(1)d and ?(2)d of the corresponding susceptibility, and obtain linear differential equations for the three and four particle contributions, as well as the five particle contribution ?(5)d, but only modulo a given prime. We use these exact linear differential equations to show that not only the Russian-doll structure but also the direct sum structure on the linear differential operators for the n-particle contributions ?(n)d are quite directly inherited from the direct sum structure on the form factors f(n). We show that the nth particle contributions ?(n)d have their singularities at roots of unity. These singularities become dense on the unit circle |sinh 2Ev/kTsinh 2Eh/kT| = 1 as n ? ?

243

Soil erodibility for water erosion: A perspective and Chinese experiences  

Science.gov (United States)

Erodibility is a key indicator to evaluate soil’s susceptibility to erosion and crucial for predicting and evaluating soil loss and its environmental effects. This review aims to synthesize almost a century’s worth of research progress on the concept, indicators, and spatio-temporal variations of so...

244

Soil enzyme activities, bacterial biomass and bacterial community structure. Changes through soil profile due to different managements  

International Nuclear Information System (INIS)

Dry climate regions are particularly susceptible to impacts from soil-degradation. In these areas, deteriorating soil quality is mainly related to inappropriate farming techniques, but the use of environmental friendly agriculture practices has proven to be effective in restoring or improving soil quality. (Author)

245

Genetic susceptibility to occupational exposures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Because of their high prevalence in the general population, genetic variants that determine susceptibility to environmental exposures may contribute greatly to the development of occupational diseases in the setting of specific exposures occurring in the workplace. Studies investigating genetic susceptibilities in the workplace may: (1) provide mechanistic insight into the aetiology of disease, in particular the determination of environmentally responsive genes; (2) identify susceptible subpo...

Christiani, D. C.; Mehta, A. J.; Yu, C-l

2008-01-01

246

Atmospheric circulation associated with extreme generalized frosts persistence in central-southern South America  

Energy Technology Data Exchange (ETDEWEB)

Generalized frosts (GF) in central-southern South America have a strong impact due to their spatial extension, and they are especially important when they become persistent. This paper aims at identifying the atmospheric circulation features that determine the extreme GF persistence, i.e. very persistent and without persistence, and the differences between them, during the 1961-1990 winters. Since the GF without persistence group outnumbers the other one, two subgroups are composed with events selected from winters with maximum and minimum frequency of GF occurrence, respectively. Additionally, the individual event of July 1988 within the very persistent GF group is analyzed due to its exceptional persistence. GF persistence is mainly conditioned by two large-scale dynamic factors. One is the Rossby wave train propagation across the Pacific Ocean, and the other one is the location with respect to the continent and the magnitude of the confluence in the jet entrance region in subtropical latitudes. A predominantly meridional Rossby wave train propagation with a confluence region to the west of the continent prior to the event favors GF with intermediate (null) persistence depending on the greater (lesser) jet acceleration. This is conditioned by the magnitude of the confluence, which, in turn, depends on the disposition of the wave train propagation pattern. Instead, an essentially zonal propagation with a confluence region to the east of the continent favors the GF persistence for several days, yet if there is no confluence the event does not persist. The greatest persistence of an event combines the confluence/diffluence of the jet entrance/exit region, which depends on the disposition with respect to the continent of the zonally propagating Rossby wave trains. (orig.)

Mueller, Gabriela V. [Centro de Investigaciones Cientificas y Transferencia de Tecnologia a la Produccion, Diamante (CICYTTTP-CONICET), Diamante, Entre Rios (Argentina); Berri, Guillermo J. [Servicio Meteorologico Nacional - CONICET, Buenos Aires (Argentina)

2012-03-15

247

Agricultural losses related to frost events: use of the 850 hPa level temperature as an explanatory variable of the damage cost  

Science.gov (United States)

The objective of this study is the analysis of damaging frost events in agriculture, by examining the relationship between the daily minimum temperature in the lower atmosphere (at an isobaric level of 850 hPa) and crop production losses. Furthermore, the study suggests a methodological approach for estimating agriculture risk due to frost events, with the aim of estimating the short-term probability and magnitude of frost-related financial losses for different levels of 850 hPa temperature. Compared with near-surface temperature forecasts, temperature forecasts at the level of 850 hPa are less influenced by varying weather conditions or by local topographical features; thus, they constitute a more consistent indicator of the forthcoming weather conditions. The analysis of the daily monetary compensations for insured crop losses caused by weather events in Greece shows that, during the period 1999-2011, frost caused more damage to crop production than any other meteorological phenomenon. Two regions of different geographical latitudes are examined further, to account for the differences in the temperature ranges developed within their ecological environment. Using a series of linear and logistic regressions, we found that minimum temperature (at an 850 hPa level), grouped into three categories according to its magnitude, and seasonality, are significant variables when trying to explain crop damage costs, as well as to predict and quantify the likelihood and magnitude of damaging frost events.

Papagiannaki, K.; Lagouvardos, K.; Kotroni, V.; Papagiannakis, G.

2014-09-01

248

The interplay between inner and outer frost damage and its implication for accelerated freeze-thaw testing  

DEFF Research Database (Denmark)

In the present project salt frost scaling was registered during an accelerated freeze-thaw test (CEN/TS 12390-9). After the test, inner damage was evaluated by observing the crack patterns on fluorescence impregnated plane sections. The results indicate that the developments of inner and outer damage are linked processes. The link is related to the moisture transport in the concrete, as both inner cracking and scaling change if a moisture barrier is implemented parallel to the test surface, 25 mm below the test surface.

Hasholt, Marianne Tange

2014-01-01

249

Heat recovery in air conditioning systems in frost-free season with using adiabatic cooling. Capacities overview  

Directory of Open Access Journals (Sweden)

Full Text Available In article the review of the information on possibilities of use of recuperators of heat is presented for the warm period of year for air-conditioning system. Aim of heat exchanger work in frost-free season is indirect cooling of incoming air before its input into maintainable premises. It is possible if exhaust air is cooled before its input into heat exchanger . In the article the operational principle of air conditioning system with using of adiabatic air cooling is considered. The data concerned system functioning depending on parameters of microclimate in maintainable premises are given.

S.V. Chuduk

2011-01-01

250

Heat recovery in air conditioning systems in frost-free season with using adiabatic cooling. Capacities overview  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In article the review of the information on possibilities of use of recuperators of heat is presented for the warm period of year for air-conditioning system. Aim of heat exchanger work in frost-free season is indirect cooling of incoming air before its input into maintainable premises. It is possible if exhaust air is cooled before its input into heat exchanger . In the article the operational principle of air conditioning system with using of adiabatic air cooling is considered. The data c...

Chuduk, S. V.

2011-01-01

251

Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rock-wall induced by natural thermal cycling and freezing/thawing. The analysis of the large catalog of events ...

Amitrano, David; Gruber, Stephan; Girard, Lucas

2012-01-01

252

Relevant magnetic and soil parameters as potential indicators of soil conservation status of Mediterranean agroecosystems  

Science.gov (United States)

The main sources of magnetic minerals in soils unaffected by anthropogenic pollution are iron oxides and hydroxides derived from parent materials through soil formation processes. Soil magnetic minerals can be used as indicators of environmental factors including soil forming processes, degree of pedogenesis, weathering processes and biological activities. In this study measurements of magnetic susceptibility are used to detect the presence and the concentration of soil magnetic minerals in topsoil and bulk samples in a small cultivated field, which forms a hydrological unit that can be considered to be representative of the rainfed agroecosystems of Mediterranean mountain environments. Additional magnetic studies such as isothermal remanent magnetization (IRM), anhysteretic remanent magnetization (ARM) and thermomagnetic measurements are used to identify and characterize the magnetic mineralogy of soil minerals. The objectives were to analyse the spatial variability of the magnetic parameters to assess whether topographic factors, soil redistribution processes, and soil properties such as soil texture, organic matter and carbonate contents analysed in this study, are related to the spatial distribution pattern of magnetic properties. The medians of mass specific magnetic susceptibility at low frequency (?lf) were 36.0 and 31.1 × 10-8 m3 kg-1 in bulk and topsoil samples respectively. High correlation coefficients were found between the ?lf in topsoil and bulk core samples (r = 0.951, p soil layers suggests enrichment in pedogenic minerals. The finer soil particles, the organic matter content and the magnetic susceptibility values are statistically correlated and their spatial variability is related to similar physical processes. Runoff redistributes soil components including magnetic minerals and exports fine particles out the field. This research contributed to further knowledge on the application of soil magnetic properties to derive useful information on soil processes in Mediterranean cultivated soils.

Quijano, Laura; Chaparro, Marcos A. E.; Marié, Débora C.; Gaspar, Leticia; Navas, Ana

2014-09-01

253

FLOOD SUSCEPTIBILITY ASSESSMENT IN THE NIRAJ BASIN  

Directory of Open Access Journals (Sweden)

Full Text Available Flood susceptibility assessment in the Niraj basin. In the context of global warming and the increasing frequency of extreme weather events, it becomes evident that we have to face natural hazards, such as floods. In the area of Niraj basin this phenomenon is specific both in the spring, because of the snow melting and of the precipitations which come along with the season, and then in the summer because of the torrential precipitations but rarely in autumn and winter. The aim of this paper is to determinate the susceptibility of the zone and obtain a map which will take into consideration the possibility of a flooding. Defining vulnerability can help us understand this type of natural disasters and find the best ways to reduce it. For this purpose we use thematic layers, morphological characteristics (slope and depth fragmentation, hydrological characteristics, geology, pedology (permeability and soil texture, landuse, precipitation data, and human interventions because in this way we have the possibility to use data mining for this purpose. Data mining will allow us to extract new information based on the existing sets of data.The final result will be a thematic map that highlights the areas which are exposed to the flood. Therefore, this map can be used as a support decision for local government or business purposes.

SANDA RO?CA

2012-03-01

254

Soil organic carbon projections in Mediterranean soils under climate change conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Soil organic carbon (SOC) plays a vital role in ecosystem function determining soil fertility, water holding capacity and susceptibility to land degradation. In addition, SOC is related to atmospheric CO2 levels with soils having the potential for C release or sequestration, depending on land use, land management, and climate. The Mediterranean region is expected to be highly affected by climate change, and it is expected that SOC decreases under climate warming conditions. Esti...

Sirca, Costantino Battista; Carta, M.; Salis, Michele; Spano, Donatella Emma Ignazia

2012-01-01

255

Soil Composition  

Science.gov (United States)

Soil is essential for life on Earth. It is needed for food, air, clothing and so much more. Discussion topics include the terms 'soil', 'dirt', and 'sediment', factors affecting the formation of soils, soil horizons, and the twelve orders of soils. In a hands-on activity, students will collect soil samples from three different locations, use online resources to determine texture and particle makeup, and record their observations.

Chris Fox

256

Aggregate-cement paste transition zone properties affecting the salt-frost damage of high-performance concretes  

International Nuclear Information System (INIS)

The influence of the cement paste-aggregate interfacial transition zone (ITZ) on the frost durability of high-performance silica fume concrete (HPSFC) has been studied. Investigation was carried out on eight non-air-entrained concretes having water-to-binder (W/B) ratios of 0.3, 0.35 and 0.42 and different additions of condensed silica fume. Studies on the microstructure and composition of the cement paste have been made by means of environmental scanning electron microscope (ESEM)-BSE, ESEM-EDX and mercury intrusion porosimetry (MIP) analysis. The results showed that the transition zone initiates and accelerates damaging mechanisms by enhancing movement of the pore solution within the concrete during freezing and thawing cycles. Cracks filled with ettringite were primarily formed in the ITZ. The test concretes having good frost-deicing salt durability featured a narrow transition zone and a decreased Ca/Si atomic ratio in the transition zone compared to the bulk cement paste. Moderate additions of silica fume seemed to densify the microstructure of the ITZ

257

The genetic potential for key biogeochemical processes in Arctic frost flowers and young sea ice revealed by metagenomic analysis.  

Science.gov (United States)

Newly formed sea ice is a vast and biogeochemically active environment. Recently, we reported an unusual microbial community dominated by members of the Rhizobiales in frost flowers at the surface of Arctic young sea ice based on the presence of 16S gene sequences related to these strains. Here, we use metagenomic analysis of two samples, from a field of frost flowers and the underlying young sea ice, to explore the metabolic potential of this surface ice community. The analysis links genes for key biogeochemical processes to the Rhizobiales, including dimethylsulfide uptake, betaine glycine turnover, and halocarbon production. Nodulation and nitrogen fixation genes characteristic of terrestrial root-nodulating Rhizobiales were generally lacking from these metagenomes. Non-Rhizobiales clades at the ice surface had genes that would enable additional biogeochemical processes, including mercury reduction and dimethylsulfoniopropionate catabolism. Although the ultimate source of the observed microbial community is not known, considerations of the possible role of eolian deposition or transport with particles entrained during ice formation favor a suspended particle source for this microbial community. PMID:24673287

Bowman, Jeff S; Berthiaume, Chris T; Armbrust, E Virginia; Deming, Jody W

2014-08-01

258

Plant survival of barbados cherry genotypes after frost injury in northern Parana State/
Recuperação de plantas de genótipos de aceroleira afetadas por geada no norte do Paraná
 

Digital Repository Infrastructure Vision for European Research (DRIVER)

Barbados cherry is a tropical fruit that when cultivated in subtropical areas is exposed to frosts which cause considerable damages to the leaves and can kill plants. The frosts of July 2000 in Northern Paraná State made possible the evaluation of 19 Barbados cherry genotypes propagated through cuttings. A minimum air temperature of –1,3°C was recorded on 17 July at the meteorological station; the minimum ground temperature was around –5,4°C. All plants were severely injured in 100% of...

Inês Cristina Batista de Fonseca; Andrey Vetorelli Borges; Fernando Tsuyoshi Aida; Ives Massanori Murata; Carmen Silvia Vieira Janeiro Neves

2002-01-01

259

Soil Moisture  

Science.gov (United States)

NOAA's Climate Prediction Center offers this useful data site on soil moisture across the US. Soil moisture data are provided here as color contour maps that represent calculated soil moisture, anomalies, and percentiles for the most recent day, monthly, and twelve-month time periods. Also provided here are 25-year average soil moisture & soil wetness summaries. In addition to providing recent and historical data, the Soil Moisture site features soil moisture forecasts for two-week, monthly, and seasonal intervals, based on the National Weather Service Medium Range Forecast (MRF) and the Constructed Analog on Soil Moisture (CAS).

2000-01-01

260

Estimation of the susceptibility at erosion and desertification in wet areas with VNIR radiometry  

International Nuclear Information System (INIS)

A multispectral technology as tool for assessing the susceptibility to erosion and desertification in humid zones from the European Mediterranean was applied by means of the use of spectral reflectance data to determine the contents of different attributes of the soils. A collection of field electromagnetic spectrums were obtained from 25 covers of soil, a derivative analysis was applied to electromagnetic spectrums and finally a PCS was made. The results showed good correlations (R2>0,5) between properties of soil and electromagnetic spectrum, therefore it is possible to determine the content of these soil attributes with spectral analysis, which minimizes cost and time. (Author) 8 refs.

 
 
 
 
261

Rossby wave propagation tracks in southern hemisphere mean basic flows associated to generalized frosts over southern South America  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish A partir de los estudios observacionales previos acerca de los eventos extremos fríos en el sudeste de América del Sur, surge la hipótesis la cual plantea que los patrones de gran escala condicionan la frecuencia de ocurrencia de heladas, a través de la propagación de ondas de Rossby excitadas remot [...] amente. Aplicando los conceptos de la teoría lineal de propagación de ondas de Rossby, el objetivo en este artículo es analizar la propagación de tales ondas en dos estados básicos diferentes referidos a los inviernos con una máxima y mínima frecuencia de ocurrencia de heladas generalizadas en la Pampa Húmeda (centro-noreste de Argentina). Basado en los conceptos teóricos acerca de la dispersión de onda y el trazo de trayectorias, se identifican los caminos preferenciales de las ondas de Rossby que alcanzan América del Sur a través de la técnica conocida como trazado de rayos. El análisis del flujo básico desde una perspectiva teórica, basado en los cálculos de las trayectorias, permite comprobar que las ondas de Rossby excitadas en forma remota son el mecanismo que favorece la máxima ocurrencia de heladas generalizadas. Siendo los lugares de excitación de tales ondas condicionados por el estado básico en que se propagan. Ellas son excitadas en lugares determinados de la atmósfera, desplazándose hasta América del Sur a lo largo de los jets que actúan como guías de dichas ondas, propiciando la generación de heladas generalizadas. En suma, este artículo presenta una revisión de la técnica de trazado de rayos y como puede ser usada para investigar la ocurrencia de importantes eventos sinópticos tales como las heladas en una región específica y su relación con la propagación de ondas planetarias de gran escala. Abstract in english Based on previous observational studies on cold extreme events over southern South America, some recent studies suggest a possible relationship between Rossby wave propagation remotely triggered and the occurrence of frost. Using the concept of linear theory of Rossby wave propagation, this paper an [...] alyzes the propagation of such waves in two different basic states that correspond to austral winters with maximum and minimum generalized frost frequency of occurrence in the Wet Pampa (central-northwest Argentina). In order to determine the wave trajectories, the ray tracing technique is used in this study. Some theoretical discussion about this technique is also presented. The analysis of the basic state, from a theoretical point of view and based on the calculation of ray tracings, corroborates that remotely excited Rossby waves is the mechanism that favors the maximum occurrence of generalized frosts. The basic state in which the waves propagate is what conditions the places where they are excited. The Rossby waves are excited in determined places of the atmosphere, propagating towards South America along the jet streams that act as wave guides, favoring the generation of generalized frosts. In summary, this paper presents an overview of the ray tracing technique and how it can be used to investigate an important synoptic event, such as frost in a specific region, and its relationship with the propagation of large scale planetary waves.

G. V., MÜLLER; T., AMBRIZZI.

2010-01-01

262

Toll-like receptor 4 region genetic variants are associated with susceptibility to melioidosis.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Melioidosis is a tropical infection caused by the Gram-negative soil saprophyte Burkholderia pseudomallei. Despite broad exposure of northeastern Thais, disease develops in only a small proportion of individuals. Although diabetes is a risk factor, the mechanisms of host susceptibility to melioidosis are still poorly understood. We postulated that Toll-like receptors (TLRs) regulate host susceptibility to disease, and that genetic variation in TLRs is associated with melioidosis. We analyzed ...

West, Te; Chierakul, W.; Chantratita, N.; Limmathurotsakul, D; Wuthiekanun, V.; Emond, Mj; Hawn, Tr; Peacock, SJ; Skerrett, Sj

2012-01-01

263

IDENTIFYING AREAS SUSCEPTIBLE TO EROSION OF EMPLOYMENT FROM USLE – UNIVERSAL SOIL LOSS EQUATION IN RIACHÃO DAS NEVES - BA. IDENTIFICAÇÃO DAS ÁREAS VULNERÁVEIS À EROSÃO A PARTIR DO EMPREGO DA EUPS – EQUAÇÃO UNIVERSAL DE PERDAS DE SOLOS NO MUNICÍPIO DE RIACHÃO DAS NEVES – BA.  

Directory of Open Access Journals (Sweden)

Full Text Available Due to agricultural expansion in the last decades, there was a considerable reduction of the Brazilian Biomes. The Bioma Cerrado, specifically, has lost 42% of its original vegetation for agricultural activities (SANO et al.,2002 , resulting in irreparable environmental damage depending on the degree of environmental degradation. Therefore the present study is to apply the EUPS - Equation Universal Soil Loss (Wischmeier & Smith, 1978 to qualitatively identify areas susceptible to erosion laminar in the city of Riachão das Neves- BA. The municipality is part of the agricultural hub of the west of Bahia in recent decades witnessed the advancement of agriculture in the region while the reduction of vegetation in places that should be preserved, especially along watercourses, thus accelerating the erosion process. Keywords: USLE, Topographic Factor, Use and Occupation of the Land.Devido à expansão agrícola das últimas décadas, houve uma redução considerável dos Biomas brasileiro. O Bioma Cerrado, especificamente, já perdeu 90% de sua vegetação original para as atividades agrícolas, tendo como consequencia perdas ambientais irreparáveis dependendo do grau de degradação do ambiente. Portanto o presente estudo faz-se a aplicação da EUPS - Equação Universal de Perdas de Solos (Wischmeier & Smith, 1978 para identificar qualitativamente áreas susceptíveis à erosão laminar no município de Riachão das Neves-BA. O município faz parte do polo agrícola do oeste baiano que nas últimas décadas presenciou o avanço da agricultura na região e ao mesmo tempo a redução da vegetação em locais que deveriam estar preservado, principalmente ao longo dos cursos d’água, acelerando assim os processos erosivos.

Rosana Sumiya Gurgel

2012-01-01

264

Magnetic susceptibility of protactinium monocarbide  

International Nuclear Information System (INIS)

The magnetic susceptibility of f.c.c. protactinium monocarbide was measured by the Faraday method between 4K and room temperature. In this temperature range, the magnetic susceptibility of PaC is very weak (about - 50.10-6 u.e.m. c.g.s/mole) and essentially temperature independent, indicating the absence of 5f electrons and the pentavalent character of Pa in this compound

265

Magnetic susceptibility of protactinium monocarbide  

International Nuclear Information System (INIS)

The magnetic susceptibility of f.c.c. protactinium monocarbide was measured by the Faraday method between 4 K and room temperature. In this temperature range, the magnetic susceptibility of PaC is very weak (about -50.10-6 u.e.m. c.g.s./mole) and essentially temperature independent, indicating the absence of 5f electrons and the pentavalent character of Pa in this compound. (author)

266

Antimicrobial susceptibility of Aeromonas hydrophila.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Minimal inhibitory concentration determinations and disk diffusion and Autobac 1 susceptibility tests were performed on 22 strains of Aeromonas hydrophila. Eleven of the strains had discrepancies between Autobac and disk diffusion or minimal inhibitory concentration results. These discrepancies occurred with the beta-lactam antibiotics, primarily carbenicillin and cephalothin. It is recommended that any strain of A. hydrophila found to be susceptible to any of the beta-lactam antibiotics by u...

Overman, T. L.

1980-01-01

267

Genetic diversity and disease susceptibility.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The range of genetic diversity within human populations is enormous. Genetic susceptibility to common chronic disease is a significant part of this genetic diversity, which also includes a variety of rare clear-cut inherited diseases. Modern DNA-based genomic analysis can now routinely lead to the identification of genes involved in disease susceptibility, provides the basis for genetic counselling in affected families, and more widely for a genetically targeted approach to disease prevention...

Bodmer, W. F.

1997-01-01

268

GIS Supported Landslide Susceptibility Modeling at Regional Scale: An Expert-Based Fuzzy Weighting Method  

Directory of Open Access Journals (Sweden)

Full Text Available The main aim of this paper is landslide susceptibility assessment using fuzzy expert-based modeling. Factors that influence landslide occurrence, such as elevation, slope, aspect, lithology, land cover, precipitation and seismicity were considered. Expert-based fuzzy weighting (EFW approach was used to combine these factors for landslide susceptibility mapping (Peloponnese, Greece. This method produced a landslide susceptibility map of the investigated area. The landslides under investigation have more or less same characteristics: lateral based and downslope shallow movement of soils or rocks. The validation of the model reveals, that predicted susceptibility levels are found to be in good agreement with the past landslide occurrences. Hence, the obtained landslide susceptibility map could be acceptable, for landslide hazard prevention and mitigation at regional scale.

Christos Chalkias

2014-04-01

269

Overview of different aspects of climate change effects on soils.  

Energy Technology Data Exchange (ETDEWEB)

Climate change [i.e., high atmospheric carbon dioxide (CO2) concentrations (?400 ppm); increasing air temperatures (2-4°C or greater); significant and/or abrupt changes in daily, seasonal, and inter-annual temperature; changes in the wet/dry cycles; intensive rainfall and/or heavy storms; extended periods of drought; extreme frost; heat waves and increased fire frequency] is and will significantly affect soil properties and fertility, water resources, food quantity and quality, and environmental quality. Biotic processes that consume atmospheric CO2 and create organic carbon (C) that is either reprocessed to CO2 or stored in soils, are the subject of active current investigations with great concern over the influence of climate change. In addition, abiotic C cycling and its influence on the inorganic C pool in soils is a fundamental global process in which acidic atmospheric CO2 participates in the weathering of carbonate and silicate minerals, ultimately delivering bicarbonate and Ca2+ or other cations that precipitate in the form of carbonates in soils or are transported to the rivers, lakes, and oceans. Soil responses to climate change will be complex, and there are many uncertainties and unresolved issues. The objective of the review is to initiate and further stimulate a discussion about some important and challenging aspects of climate-change effects on soils, such as accelerated weathering of soil minerals and resulting C and elemental fluxes in and out of soils, soil/geo-engineering methods used to increase C sequestration in soils, soil organic matter (SOM) protection, transformation and mineralization, and SOM temperature sensitivity. This review reports recent discoveries and identifies key research needs required to understand the effects of climate change on soils.

Qafoku, Nikolla

2014-08-01

270

Mediterranean soils  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mediterranean soils are soils which form under a Mediterranean climate. They are variously called Terra Rossa (on hard limestone) and Red Mediterranean Soils. Not all soils in a Mediterranean environment are, however, qualified as such because normal pedogenetic development may be hampered by erosion (rejuvenation of the profile), lack of time, lack of water or unfavorable parent material characteristics.

Verheyen, Willy; La Rosa, Diego

2005-01-01

271

Landslide susceptibility analysis using Probabilistic Certainty Factor Approach: A case study on Tevankarai stream watershed, India  

Science.gov (United States)

This paper reports the use of a GIS based Probabilistic Certainty Factor method to assess the geo-environmental factors that contribute to landslide susceptibility in Tevankarai Ar sub-watershed, Kodaikkanal. Landslide occurrences are a common phenomenon in the Tevankarai Ar sub-watershed, Kodaikkanal owing to rugged terrain at high altitude, high frequency of intense rainfall and rapidly expanding urban growth. The spatial database of the factors influencing landslides are compiled primarily from topographical maps, aerial photographs and satellite images. They are relief, slope, aspect, curvature, weathering, soil, land use, proximity to road and proximity to drainage. Certainty Factor Approach is used to study the interaction between the factors and the landslide, highlighting the importance of each factor in causing landslide. The results show that slope, aspect, soil and proximity to roads play important role in landslide susceptibility. The landslide susceptibility map is classified into five susceptible classes - low, very low, uncertain, high and very high - 93.32% of the study area falls under the stable category and 6.34% falls under the highly and very highly unstable category. The relative landslide density index (R index) is used to validate the landslide susceptibility map. R index increases with the increase in the susceptibility class. This shows that the factors selected for the study and susceptibility mapping using certainty factor are appropriate for the study area. Highly unstable zones show intense anthropogenic activities like high density settlement areas, and busy roads connecting the hill town and the plains.

Sujatha, Evangelin Ramani; Rajamanickam, G. Victor; Kumaravel, P.

2012-10-01

272

Geotechnical characteristics of residual soils  

Energy Technology Data Exchange (ETDEWEB)

Residual soils are products of chemical weathering and thus their characteristics are dependent upon environmental factors of climate, parent material, topography and drainage, and age. These conditions are optimized in the tropics where well-drained regions produce reddish lateritic soils rich in iron and aluminum sesquioxides and kaolinitic clays. Conversely, poorly drained areas tend towards montmorillonitic expansive black clays. Andosols develop over volcanic ash and rock regions and are rich in allophane (amorphous silica) and metastable halloysite. The geological origins greatly affect the resulting engineering characteristics. Both lateritic soils and andosols are susceptible to property changes upon drying, and exhibit compaction and strength properties not indicative of their classification limits. Both soils have been used successfully in earth dam construction, but attention must be given to seepage control through the weathered rock. Conversely, black soils are unpopular for embankments. Lateritic soils respond to cement stabilization and, in some cases, lime stabilization. Andosols should also respond to lime treatment and cement treatments if proper mixing can be achieved. Black expansive residual soils respond to lime treatment by demonstrating strength gains and decreased expansiveness. Rainfall induced landslides are typical of residual soil deposits.

Townsend, F.C.

1985-01-01

273

Impact of climate change, seedling type and provenance on the risk of damage to Norway spruce (Picea abies (L.) Karst.) seedlings in Sweden due to early summer frosts  

Energy Technology Data Exchange (ETDEWEB)

A model including site-specific microclimate-affecting properties of a forest regeneration area together with seedling characteristics was used to evaluate the accumulated risk of frost damage to Norway spruce (Picea abies (L.) Karst.) seedlings. Climate change in Sweden was simulated on the basis of the regional climate model RCA3. The daily average temperature, the driving factor for bud burst in the model, was adjusted using the difference between the mean of the climate model data for the years 1961-1990 and 2036-2065. The model was run for a highly frost prone, clear-cut site in which bare-rooted Norway spruce seedlings of mid-Swedish provenance were planted. Alternate runs were conducted with data for containerized seedlings and seedlings of Belarusian origin. The study showed that bud burst will occur at earlier dates throughout Sweden in the period 2036-2065 if the climate changes according to either of the climate scenarios examined, compared to the reference period 1961-1990. Furthermore, the risk of damage to Norway spruce seedlings as a result of frost events during summer will increase in southern Sweden and be unaffected or decrease in northern Sweden. The risk of frost damage was exacerbated in containerized seedlings, while the risk was lower for the seedlings of Belarusian provenance when compared with bare-rooted seedlings or seedlings of mid-Swedish origin

Langvall, Ola (Swedish Univ. of Agricultural Sciences, Unit for Field-based Forest Research, Asa Forest Research Station, Lammhult (Sweden))

2011-04-15

274

Cement mortar-degraded spinney waste composite as a matrix for immobilizing some low and intermediate level radioactive wastes: Consistency under frost attack  

International Nuclear Information System (INIS)

Highlights: ? Spinney fiber is one of the wastes generated from spinning of cotton raw materials. ? Cement mortar composite was hydrated by using the degraded slurry of spinney wastes. ? Frost resistance was assessed for the mortar-degraded spinney waste composite specimens. ? SEM image, FT-IR and XRD patterns were performed for samples subjected to frost attack. - Abstract: The increasing amounts of spinning waste fibers generated from cotton fabrication are problematic subject. Simultaneous shortage in the landfill disposal space is also the most problem associated with dumping of these wastes. Cement mortar composite was developed by hydrating mortar components using the waste slurry obtained from wet oxidative degradation of these spinney wastes. The consistency of obtained composite was determined under freeze–thaw events. Frost resistance was assessed for the mortar composite specimens by evaluating its compressive strength, apparent porosity and mass loss at the end of each period of freeze–thaw up to 45 cycles. Scanning electron microscopy, infrared spectroscopy and X-ray diffraction analyses were performed for samples subjected to frost attack aiming at evaluating the cement mortar in the presence of degraded spinney waste. The cement mortar composite exhibits acceptable resistance and durability against the freeze–thaw treatment that could be chosen in radioactive waste management as immobilizing agent for some low and intermediate level radioand intermediate level radioactive wastes.

275

Identification and frequency of atmospheric circulation patterns causing spring frost in the northern French vineyards using the objective version of the Hess-Brezowsky classification  

Science.gov (United States)

The possible impacts of climate change at small spatial scales are still very little known. The knowledge of the climate risks at small scales is yet essential for agricultural activities and productions like vine growing, because of their serious economic impacts. Because of their relatively high latitude, the vineyards of the northern Half of France are subjected to spring frost, which can cause serious damages e.g. in the Champagne area on April the 8th, 2003. A detailed study of the variability and frequency of spring frost events in four vineyards (Loire Valley, Champagne, Burgundy and Alsace) was carried out within the framework of the RICLIM-CNRS 2663 multidisciplinary Research Group "Climate Risks" and was supported by the research program TERVICLIM (ANR-JC07-194103) and by the MAIF Foundation (program about air-mass circulation dynamics and climate risks). The northern Half of France is included in the Cfb type of climate (according to the Köppen's classification) of northwestern and central Europe. However, the combined effects of the latitude, the continentality and the topography involve varied regional climates. Among the four studied wine-producing areas, the Loire Valley area is the warmest, the Champagne area is the coolest in summer, and eastern Burgundy and especially Alsace are the most subjected to the continentality effect (highest annual temperature oscillation and highest rainfall amounts in summer). Therefore, these areas are not equally subjected to the frost risk. Spring is a key season for the vine growing and during frost-producing weather patterns, northern France is subjected to a high spatial variability of temperature at regional and local scales. During the period 1960-2007, the number of spring frost day events was three times as high in Colmar (Alsace) than in Saumur (Loire Valley). Among the four wine-producing areas, Alsace records the most hard and frequent frosts in early spring, while the Champagne area records the latest frosts (until June). In the Loire Valley area, frost is rare as early as April. The combined effects of the continentality and the topographical features of the Upper Rhine Graben explain the hard frosts in early spring at Colmar, but also higher temperature at Colmar than at Reims from April. The Champagne area is the most exposed to frost-producing North-Westerly and Northerly atmospheric circulations in late spring (e.g. on May the 5th, 1996: minimum temperature of -1°C at Reims / Champagne and +3.8°C at Colmar). The identification and frequency of atmospheric circulation patterns causing spring frost (daily minimum temperature below 0°C) and hard frost (daily minimum temperature below -5°C) were carried out using the objective computational version of the 29-type Hess and Brezowsky Grosswetterlagen system of classifying European synoptic regimes (James, 2007). Minimum temperature data were got from the Meteo-France database (Climathèque), for the spring months (March, April and May) and for the period 1960-2007, at the weather stations of Saumur (Loire Valley), Reims (Champagne), Dijon (Burgundy) and Colmar (Alsace). More than 40% of the frost days occurring at all weather stations were associated with North-Westerly and Northerly circulation types, 27% with North-Easterly and Easterly circulation types and 16% with a main high or low pressure area over central Europe. More precisely, the cyclonic circulations involving a northerly flow over western Europe (15.6%) and Anticyclonic North-Easterly circulations (9,3%) are the most frequent circulations types associated with frost days. These circulation types bring air-masses favourable to radiation cooling, under clear sky and light wind, or cold air-masses from northern or eastern Europe causing advection cooling. The stations of eastern France can be subjected to frost events even during Westerly or Southerly circulations, while frost occurrence in the Saumur area requires a higher ratio of North-Easterly and Easterly circulations (10% at Colmar ; 37% at Saumur). Because of the location of Saum

Quénol, H.; Planchon, O.; Wahl, L.

2009-04-01

276

Soil erodibility degree assessment on hilly terrain  

International Nuclear Information System (INIS)

A study was initiated to classify and predict potential landslide locations of occurrence at both well known highland resort areas of Malaysia namely Fraser Hill and Genting Highlands. The classification was done by determining the soil susceptibility for failure in terms of its soil erodibility index value with regards to the ROM Scale. Soil samples were taken on slopes at every 1 km stretch along the main road leading to both highlands. Concurrently, daily rainfall data of both areas were thoroughly examined to determine the erosion risk frequency. From the soil samples analysis, Km 13-14 in Genting Highlands had been identified as the most susceptible location to landslide risk, while for Fraser Hill, Km 4-5 tops the ranking. The analyzed rainfall data however, had shown that the erosion frequency is at the highest risk in the month of November and September for both Genting Highlands and Fraser Hill respectively. (Author)

277

Susceptibility of Aeromonas Hydophila Isolates to Antimicrobial Drugs  

Directory of Open Access Journals (Sweden)

Full Text Available Aeromonas hydrophila is a microorganism widely distributed in nature: in water, soil, food. It is also part of the normal bacterial flora of many animals. As an opportune microorganism it is a secondary biological agent that contributes to the occurrence of a fish disease and its deterioration. Frequently, its presence is an indication of bad zoohygiene and zootechnical conditions in fish ponds. Reduced quality and quantity of feed, mechanical injuries, parasitosis, seasonal oscillation in temperature present some of the factors that produce favorable conditions for bacterial proliferation of aeromonas in fish ponds, so clinical symptoms of the disease occur. Aeromonas is almost always present in clinical isolates and may be unjustly accused for bad health of fish. Antibiotic therapy is applied even when the clinical findings are clear, what certainly effects the susceptibility to chemotherapeutics. The subject of our work was bacteriological examination of the material obtained from the carps with the observed skin changes and the carps without these changes. Also, antimicrobial susceptibility of Aeromonas hydrophila was tested. The aim of this research was to determined the presence of Aeromonas hydrophilia in the carp ponds and to test antibiotic susceptibility. The material consisted of the samples from the fish ponds where the carps were with and without changed skin. The method the isolation of Aeromonas hydrophila was used. The diffusion disk technique was used for testing antibiotic susceptibility. The isolates were tested for their susceptibility to Florephenikol, Flumequine, Olaqindox and Oxitetracycline. The obtained results point that antimicrobial susceptibility was the same regardless of the origin of the samples, i.e. the resistance was the same for both groups of samples (the strains isolated from the fish with skin changes and the strains from fish without changes on skin. The strains were highly resistant: 35% were resistant to flumequine and 40% to Oxitetracycline.

Igor Stojanov

2010-05-01

278

Manifestation of a neuro-fuzzy model to produce landslide susceptibility map using remote sensing data derived parameters  

Science.gov (United States)

Landslides are the most common natural hazards in Malaysia. Preparation of landslide suscep-tibility maps is important for engineering geologists and geomorphologists. However, due to complex nature of landslides, producing a reliable susceptibility map is not easy. In this study, a new attempt is tried to produce landslide susceptibility map of a part of Cameron Valley of Malaysia. This paper develops an adaptive neuro-fuzzy inference system (ANFIS) based on a geographic information system (GIS) environment for landslide susceptibility mapping. To ob-tain the neuro-fuzzy relations for producing the landslide susceptibility map, landslide locations were identified from interpretation of aerial photographs and high resolution satellite images, field surveys and historical inventory reports. Landslide conditioning factors such as slope, plan curvature, distance to drainage lines, soil texture, lithology, and distance to lineament were extracted from topographic, soil, and lineament maps. Landslide susceptible areas were analyzed by the ANFIS model and mapped using the conditioning factors. Furthermore, we applied various membership functions (MFs) and fuzzy relations to produce landslide suscep-tibility maps. The prediction performance of the susceptibility map is checked by considering actual landslides in the study area. Results show that, triangular, trapezoidal, and polynomial MFs were the best individual MFs for modelling landslide susceptibility maps (86

Pradhan, Biswajeet; Lee, Saro; Buchroithner, Manfred

279

Air-side performance evaluation of three types of heat exchangers in dry, wet and periodic frosting conditions  

Energy Technology Data Exchange (ETDEWEB)

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)

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

280

Susceptibility Genes in Thyroid Autoimmunity  

Directory of Open Access Journals (Sweden)

Full Text Available The autoimmune thyroid diseases (AITD are complex diseases which are caused by an interaction between susceptibility genes and environmental triggers. Genetic susceptibility in combination with external factors (e.g. dietary iodine is believed to initiate the autoimmune response to thyroid antigens. Abundant epidemiological data, including family and twin studies, point to a strong genetic influence on the development of AITD. Various techniques have been employed to identify the genes contributing to the etiology of AITD, including candidate gene analysis and whole genome screening. These studies have enabled the identification of several loci (genetic regions that are linked with AITD, and in some of these loci, putative AITD susceptibility genes have been identified. Some of these genes/loci are unique to Graves' disease (GD and Hashimoto's thyroiditis (HT and some are common to both the diseases, indicating that there is a shared genetic susceptibility to GD and HT. The putative GD and HT susceptibility genes include both immune modifying genes (e.g. HLA, CTLA-4 and thyroid specific genes (e.g. TSHR, Tg. Most likely, these loci interact and their interactions may influence disease phenotype and severity.

Yaron Tomer

2005-01-01

 
 
 
 
281

Subsoil compaction caused by heavy sugarbeet harvesters in southern Sweden; III. risk assessment using a soil water model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Due to its persistence, subsoil compaction should be avoided, which can be done by setting stress limits depending on the strength of the soil. Such limits must take into account soil moisture status at the time of traffic. The objective of the work presented here was to measure soil water changes during the growing period, use the data to calibrate a soil water model and simulate the soil susceptibility to compaction using meteorological data for a 25-year period. Measurements of soil water ...

Arvidsson, J.; Sjo?berg, E.; Akker, J. J. H.

2003-01-01

282

A next generation sequencing of Arctic bacteria in snow and frost flowers: identification, abundance and freezing nucleation  

Science.gov (United States)

During the spring of 2009, as part of the Ocean-Atmosphere-Sea Ice-Snowpack (OASIS) campaign in Barrow, Alaska, USA, we examined the identity, population, freezing nucleation ability of the microbial communities of five different snow types and frost flowers. In addition to the conventional culture-based PCR identification approach, we deployed a state-of-the-art genomic Next Generation Sequencing (NGS) technique to examine diverse bacterial communities in Arctic samples. 11-18 known phyla or candidate divisions were identified with the great majority of sequences (12.3-83.1%) belonging to one of the five major phyla: Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Cyanobacteria. At the genus level, 101-245 different genera were detected. The highest number of cultivable bacteria in cultured samples was observed in frost flowers (FF) and accumulated snow (AS) with 325 ± 35 and 314 ± 142 CFU mL-1, respectively; and for cultivable fungi 5 ± 1 CFU mL-1 in windpack (WP) and blowing snow (BS). Complementary morphology and ice-nucleating abilities of the identified taxa were obtained using high resolution electron microscopy and ice nucleation cold-plate, respectively. Freezing point temperatures for bacterial isolate ranged from -20.3 ± 1.5 to -15.7 ± 5.6 °C, and for melted samples from 9.5 ± 1.0 to 18.4 ± 0.1 °C. An isolate belonging to the Bacillus species (96% similarity) had ice nucleation activity of -6.8 ± 0.2 °C. Comparison with Montreal urban snow, revealed a seemingly diverse community of bacteria exists in the Arctic with many originating from distinct ecological environments, and we discuss the potential impact of microbial snow in the freezing and melting process of the snowpack in the Arctic.

Mortazavi, R.; Attiya, S.; Ariya, P. A.

2014-12-01

283

Efficacy of cervicothoracic sympathectomy versus conservative management in patients suffering from incapacitating raynaud,s syndrome after frost bite  

International Nuclear Information System (INIS)

Raynaud's syndrome is a known complication of cold injuries. Stress, smoking and metabolic diseases may further aggravate the disease course. The purpose of this study was to determine the efficacy of Cervico-thoracic sympathectomy as compared to conservative management in severe Raynaud's syndrome after frostbite. This non-randomized controlled trial was conducted at Railway Hospital, Rawalpindi and Islamic International Medical Complex, Islamabad between January 1999 and June 2006. All patients sustained severe cold trauma in the mountain ridges of Himalayas in Kashmir. In all cases, an informed consent was obtained from patients and families. All operations performed were free of charges. Out of the total 48 patients who developed incapacitating Raynaud's syndrome of the upper limbs after frost bite, 17 patients underwent thoracic sympathectomy through anterior supraclavicular route. Remaining 31 patients were treated conservatively and were placed in the control group. Data was collected on pre-designed proforma and assessed using SPSS (version 11). Chi-square test was applied to assess the effectiveness of the two treatment modalities. All operated cases initially showed improvement in symptoms and incapacitation. Among sympathectomised patients, 11 patients became symptom free and 3 patients showed mild but improved symptoms. Two patients after initial transient improvement developed incapacitating symptoms requiring further treatment, one patient developed gangther treatment, one patient developed gangrene of distal phalanx nine month after sympathectomy requiring amputation of the finger. Frequency of attacks and duration between the attacks reduced in all operated patients of cervical sympathectomy (p<0.05) as compared to conservative management. Cervical sympathectomy is a very effective modality of treatment in patients having severe Raynaud's disease of upper limbs secondary to frost bite. (author)

284

Soil Texture  

Science.gov (United States)

This University of Florida website educates the public about soil texture, which is the distribution of sizes of mineral particles found in soils. After learning the basics about soil separates, students and educators can learn about the USDA textural triangle and the characteristics of the twelve textural classes. Researchers can discover how to determine the correct soil texture in the field. The website addresses the important role soil textures play in the determination of proper land use activities and management practices. Visitors will also find a short discussion about other factors that affect the behavior and qualities of soils.

2008-01-04

285

Magnetic Susceptibility of Multiorbital Systems  

CERN Document Server

Effects of orbital degeneracy on magnetic susceptibility in paramagnetic phases are investigated within a mean-field theory. Under certain crystalline electric fields, the magnetic moment consists of two independent moments, e.g., spin and orbital moments. In such a case, the magnetic susceptibility is given by the sum of two different Curie-Weiss relations, leading to the deviation from the Curie-Weiss law. Such behavior may be observed in d- and f-electron systems with t_{2g} and Gamma_8 ground states, respectively. As a potential application of our theory, we attempt to explain the difference in the temperature dependence of magnetic susceptibilities of UO_2 and NpO_2.

Kubo, K; Kubo, Katsunori; Hotta, Takashi

2006-01-01

286

Magnetic susceptibility of multiorbital systems  

International Nuclear Information System (INIS)

Effects of orbital degeneracy on magnetic susceptibility in parametric phases are investigated within a mean-field theory. Under certain crystalline electric fields, the magnetic moment consists of two independent moments, e.g., spin and orbital moments. In such a case, the magnetic susceptibility is given by the sum of two different Curie-Weiss relations, leading to deviation from the Curie-Weiss law. Such behavior may be observed in d- and f-electron systems with t2g and ?8 ground states, respectively. As a potential application of our theory, we attempt to explain the difference in the temperature dependence of magnetic susceptibilities of UO2 and NpO2. (author)

287

Identifying areas susceptible to desertification in the Brazilian Northeast  

Science.gov (United States)

Approximately 57% of the Brazilian Northeast region is recognized as semiarid land and has been undergoing intense land use processes in the last decades, which have resulted in severe degradation of its natural assets. Therefore, the objective of this study is to identify the areas that are susceptible to desertification in this region based on the eleven driving factors of desertification (pedology, geology, geomorphology, topography data, land use and land cover change, aridity index, livestock density, rural population density, fire hot spot density, human development index (HDI), conservation units) which were model-simulated for two different periods: 2000 and 2010. Each indicator were assigned weights ranging from 1 to 2 (representing the best and the worst conditions), representing classes indicating low, moderate and high susceptibility to desertification. The result indicates that 94% of the Brazilian Northeast region is under moderate to high susceptibility to desertification. The areas that were susceptible to soil desertification increased by approximately 4.6% (83.35 km2) from 2000 to 2010. The implementation of the methodology provide the technical basis for decision making that involves mitigating actions, as well as the first comprehensive national assessment within the United Nations Convention to Combat Desertification framework.

da Silva Pinto Vieira, R. M.; Tomasella, J.; dos Santos Alvalá, R. C.; Sestini, M. F.; Affonso, A. G.; Rodriguez, D. A.; Barbosa, A. A.; do Amaral Cunha, A. P. M.; de Fátima Valles, G.; Crepani, E.; de Oliveira, S. B. P.; Benício de Souza, M. S.; Calil, P. M.; de Carvalho, M. A.; de Morisson Valeriano, D.; Campello, F. C. B.; Santana, M. O.

2014-12-01

288

Inherited susceptibility and radiation exposure  

International Nuclear Information System (INIS)

There is continuing concern that some people in the general population may have genetic makeups that place them at particularly high risk for radiation-induced cancer. The existence of such a susceptible subpopulation would have obvious implications for the estimation of risks of radiation exposure. Although it has been long known that familial aggregations of cancer do sometimes occur, recent evidence suggests that a general genetic predisposition to cancer does not exist; most cancers occur sporadically. On the other hand, nearly 10% of the known Mendelian genetic disorders are associated with cancer. A number of these involve a familial predisposition to cancer, and some are characterized by an enhanced susceptibility to the induction of cancer by various physical and chemical carcinogens, including ionizing radiation. Such increased susceptibility will depend on several factors including the frequency of the susceptibility gene in the population and its penetrance, the strength of the predisposition, and the degree to which the cancer incidence in susceptible individuals may be increased by the carcinogen. It is now known that these cancer-predisposing genes may be responsible not only for rare familial cancer syndromes, but also for a proportion of the common cancers. Although the currently known disorders can account for only a small fraction of all cancers, they serve as models for genetic predisposition to carcinogen-induced cancer in the general population. Induced cancer in the general population. In the present report, the author describes current knowledge of those specific disorders that are associated with an enhanced predisposition to radiation-induced cancer, and discusses how this knowledge may bear on the susceptibility to radiation-induced cancer in the general population and estimates of the risk of radiation exposure

289

Análisis de la distribución de raíces de 12 patrones injertados con naranja "frost valencia" Citrus sinensis L. oesbeck de 14 años de edad, en condiciones climáticas de Palmira, Valle del Cauca Analysis of root distribution in 12 citrus rootstocks grown in Palmira, the Cauca Valley  

Directory of Open Access Journals (Sweden)

Full Text Available

En el Centro Nacional de Investigaciones del ICA, Palmira, se estudió el sistema de raíces de 12 patrones injertados con naranja Frost Valencia, de 14 años de edad, sembrados en un suelo Franco-Arcilloso. Se tomaron muestras a 1.0, 1,5, 2.0 y 3.0 m de distancia de la base del árbol y a profundidades de 0-20, 20-40, 40-60, 60-80 Y 80-100 cm, considerando cada distancia. Los patrones que mostraron la mayor densidad de raíces fueron: Amblycarpa, Citrange Carrizo y Mandarina Cleopatra. Se encontró correlación directa y altamente significativa entre el sistema de raíces menores de 2 mm de diámetro con la altura y diámetro del árbol, lo mismo que con el volumen de la copa. Estos aspectos son de especial importancia para evaluar el grado de adaptación a diferentes condiciones de suelo, al momento de plantar un huerto.

At the ICA National Research Center in Palmira a study of the root system of 12 rootstocks grafted with "Frost Valencia" orange 14 years old grown on clay-loam soil was conducted. Root samples were taken at distances of 1.0, 1.5, 2.0 and 3.0 m from stem and a depth of 0-20, 20-40, 40-60, 60-80 and 80-100 cm in each distances. The rootstocks Amblycarpa, Citrange Carrizo and Cleopatra Mandarin presented the greater root densities. The height, diameter and the foliage tree volume showed positive correlation whit a diameter lesser than two millimeter. That's special importance for the adaptation several soil's conditions.

Escobar T. William

1992-12-01

290

The use of magnetic susceptibility as a forensic search tool.  

Science.gov (United States)

There are various techniques available for forensic search teams to employ to successfully detect a buried object. Near-surface geophysical search methods have been dominated by ground penetrating radar but recently other techniques, such as electrical resistivity, have become more common. This paper discusses magnetic susceptibility as a simple surface search tool illustrated by various research studies. These suggest magnetic susceptibility to be a relatively low cost, quick and effective tool, compared to other geophysical methods, to determine disturbed ground above buried objects and burnt surface remains in a variety of soil types. Further research should collect datasets over objects of known burial ages for comparison purposes and used in forensic search cases to validate the technique. PMID:25460105

Pringle, Jamie K; Giubertoni, Matteo; Cassidy, Nigel J; Wisniewski, Kristopher D; Hansen, James D; Linford, Neil T; Daniels, Rebecca M

2015-01-01

291

Coupled Water Flow and Heat Transport in Seasonally Frozen Soils with Snow Accumulation  

Science.gov (United States)

A numerical model is developed to calculate coupled water flow and heat transport in seasonally frozen soil and snow. Separate equations are used to describe both unsaturated and saturated soil water flow. The effect of dissolved ions on soil water freezing point depression is included by combining an expression for osmotic head with the Clapeyron equation and the van Genuchten soil water retention function. The coupled water flow and heat transport equations are solved using the Thomas algorithm and Picard iteration. Ice pressure is always assumed zero and frost heave is neglected. The new model is tested using data from an existing laboratory soil column freezing experiment and an ongoing field experiment in a high-elevation rangeland soil. A dimensionless impedance factor describing the effect of ice pore blocking on soil hydraulic conductivity is treated as a calibration parameter for both cases. Calculated values of total water content for the laboratory soil column freezing experiment compare well with measured values, especially during the early stages of the experiment, as is also found by others. Modeling statistics for the rangeland field experiment show varied performance for soil water content and excellent performance for soil temperature, in accordance with earlier results with an older version of the model.

King, J. M.; Kasurak, A.; Kelly, R. E.; Duguay, C. R.; Derksen, C.

2011-12-01

292

Solarization soil  

International Nuclear Information System (INIS)

Solar energy could be used in pest control, in soil sterilization technology. The technique consists of covering humid soils by plastic films steadily fixed to the soil. Timing must be in summer during 4-8 weeks, where soil temperature increases to degrees high enough to control pests or to produce biological and chemical changes. The technique could be applied on many pests soil, mainly fungi, bacteria, nematods, weeds and pest insects. The technique could be used in greenhouses as well as in plastic film covers or in orchards where plastic films present double benefits: soil sterilization and production of black mulch. Mechanism of soil solarization is explained. Results show that soil solarization can be used in pest control after fruit crops cultivation and could be a method for an integrated pest control. 9 refs

293

Soil Erosion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data of the Soil Erosion. The word "erosion" is derived from the Latin "erosio", meaning to "to gnaw away". In general terms soil erosion implies the physical removal of topsoil by various agents, including rain, water flowing over and through the soil profile, wind, ice or gravitational pull. This part of the CIVCAL project introduces the processes and control of soil erosion, includi...

Kumaraswamy, Mohan

2002-01-01

294

Susceptibility of a Heisenberg antiferromagnet  

International Nuclear Information System (INIS)

The spin-wave Hamiltonian for the two sublattice Heisenberg antiferromagnet is obtained using a Maleev transformation. The dipole-dipole interaction is restricted to nearest neighbours. The double-time Green function formulation is used to obtain the expression, up to first order, of the sixteen elementary two-operator Green functions. These are used to obtain the frequency-dependent susceptibility. (author)

295

Insecticide susceptibility of cimex hemipterus  

Directory of Open Access Journals (Sweden)

Full Text Available The susceptibility of the bed bug, cimex hemiptelus fabricius, to certain synthetic contact insecticides, viz., DDT, lindane dieldrin, diazinon and malathion was investigated. The fifth nymphal stage of the insect was found to be more tolerant to insecticides than other nymphal instars or the adult bed bug.

S. L. Perti

2014-05-01

296

Antimicrobial susceptibilities of Erysipelothrix rhusiopathiae.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The in vitro susceptibilities of 10 isolates of Erysipelothrix rhusiopathiae to 16 antimicrobial agents were determined. Penicillin and imipenem were the most active agents, followed by piperacillin, cefotaxime, ciprofloxacin, pefloxacin, and clindamycin. Some resistance was observed with erythromycin, tetracycline, and chloramphenicol. Activity was poor or absent with vancomycin, teicoplanin, daptomycin, trimethoprim-sulfamethoxazole, gentamicin, and netilmicin.

Venditti, M.; Gelfusa, V.; Tarasi, A.; Brandimarte, C.; Serra, P.

1990-01-01

297

Evaluación de poblaciones nativas de maíz en ambientes con heladas en Valles Altos de Puebla / Evaluation of maize native population in environments with frosts in High Valleys, Puebla  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish En México la superficie sembrada con maíz es de ocho millones de hectáreas, de las cuales 1.2% es siniestrada por heladas. En el estado de Puebla este porcentaje es 0.8% y en Valles Altos 1.7%. El objetivo de este estudio, fue evaluar el efecto de las heladas en rendimiento de grano y seleccionar po [...] blaciones nativas con mayor rendimiento en ambientes con presencia de heladas. Para ello se evaluaron 61 poblaciones nativas y tres variedades mejoradas, mediante un diseño experimental látice simple 8*8 con dos repeticiones. Los experimentos se establecieron en tres localidades del estado de Puebla. Las fechas de siembra fueron el 30 de marzo en Emiliano Zapata, Cuyoaco, el 7 de abril en Santa Inés Borbolla, Chalchicomula de Sesma y el 4 de mayo en Santa Cruz Coyotepec, San Juan Atenco; estas localidades se caracterizan por ser de temporal y con presencia de heladas en 2007. El análisis de varianza combinado indicó que las heladas afectaron el rendimiento de grano de las poblaciones nativas y mejoradas; pero hubo variedades como la CPue-131, CPue-448 y CPue-134 que mostraron mayor rendimiento promedio y mayor estabilidad ambiental que las mejoradas. La prueba de medias para localidades en el análisis combinado, indicó que Emiliano Zapata fue el ambiente menos afectado por heladas con 3 510 kg ha-1. Abstract in english In Mexico, the maize planted area is eight million hectares, out of which 1.2% is stricken by frost. In Puebla State, this percentage is 0.8% and 1.7% in High Valleys. The aim of this study was to evaluate the effect of frost on grain yield and to select native populations with higher performance in [...] presence of frost. 61 native populations and three improved varieties were evaluated, through a simple lattice design 8*8 with two repetitions. The experiments were established at three locations in Puebla State. Planting dates were March 30th in Emiliano Zapata, Cuyoaco; April 7th in Santa Inés Borbolla, Chalchicomula de Sesma and May 4th in Santa Cruz Coyotepec, San Juan Atenco; these locations are characterized by its rainfed conditions and frosts in 2007. The combined analysis of variance indicated that the frosts affected grain yield of native and improved populations; but there were varieties such as CPue-131, CPue-448 and CPue-134 that showed a higher average yield and environmental stability that improved varieties. Mean test for locations in the combined analysis indicated that Emiliano Zapata was the least affected by frost with 3 510 kg ha-1.

Ricardo, Pérez-de la Luz; Higinio, López-Sánchez; Pedro Antonio, López; Abel, Gil-Muñoz; Amalio, Santacruz-Varela; Juan de Dios, Guerrero-Rodríguez.

2011-10-01

298

Evaluación de poblaciones nativas de maíz en ambientes con heladas en Valles Altos de Puebla Evaluation of maize native population in environments with frosts in High Valleys, Puebla  

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Full Text Available En México la superficie sembrada con maíz es de ocho millones de hectáreas, de las cuales 1.2% es siniestrada por heladas. En el estado de Puebla este porcentaje es 0.8% y en Valles Altos 1.7%. El objetivo de este estudio, fue evaluar el efecto de las heladas en rendimiento de grano y seleccionar poblaciones nativas con mayor rendimiento en ambientes con presencia de heladas. Para ello se evaluaron 61 poblaciones nativas y tres variedades mejoradas, mediante un diseño experimental látice simple 8*8 con dos repeticiones. Los experimentos se establecieron en tres localidades del estado de Puebla. Las fechas de siembra fueron el 30 de marzo en Emiliano Zapata, Cuyoaco, el 7 de abril en Santa Inés Borbolla, Chalchicomula de Sesma y el 4 de mayo en Santa Cruz Coyotepec, San Juan Atenco; estas localidades se caracterizan por ser de temporal y con presencia de heladas en 2007. El análisis de varianza combinado indicó que las heladas afectaron el rendimiento de grano de las poblaciones nativas y mejoradas; pero hubo variedades como la CPue-131, CPue-448 y CPue-134 que mostraron mayor rendimiento promedio y mayor estabilidad ambiental que las mejoradas. La prueba de medias para localidades en el análisis combinado, indicó que Emiliano Zapata fue el ambiente menos afectado por heladas con 3 510 kg ha-1.In Mexico, the maize planted area is eight million hectares, out of which 1.2% is stricken by frost. In Puebla State, this percentage is 0.8% and 1.7% in High Valleys. The aim of this study was to evaluate the effect of frost on grain yield and to select native populations with higher performance in presence of frost. 61 native populations and three improved varieties were evaluated, through a simple lattice design 8*8 with two repetitions. The experiments were established at three locations in Puebla State. Planting dates were March 30th in Emiliano Zapata, Cuyoaco; April 7th in Santa Inés Borbolla, Chalchicomula de Sesma and May 4th in Santa Cruz Coyotepec, San Juan Atenco; these locations are characterized by its rainfed conditions and frosts in 2007. The combined analysis of variance indicated that the frosts affected grain yield of native and improved populations; but there were varieties such as CPue-131, CPue-448 and CPue-134 that showed a higher average yield and environmental stability that improved varieties. Mean test for locations in the combined analysis indicated that Emiliano Zapata was the least affected by frost with 3 510 kg ha-1.

Ricardo Pérez-de la Luz

2011-10-01

299

Soil, resilience, and state and transition models  

Science.gov (United States)

State and transition models are based on the assumption that less resilient systems are more susceptible to state changes. The objective of this paper is to show how two different types of soil properties contribute to resilience through their direct and indirect effects on ecosystem processes, and ...

300

Landslide susceptibility mapping using a neuro-fuzzy  

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This paper develops and applied an adaptive neuro-fuzzy inference system (ANFIS) based on a geographic information system (GIS) environment using landslide-related factors and location for landslide susceptibility mapping. A neuro-fuzzy system is based on a fuzzy system that is trained by a learning algorithm derived from the neural network theory. The learning procedure operates on local information, and causes only local modifications in the underlying fuzzy system. The study area, Boun, suffered much damage following heavy rain in 1998 and was selected as a suitable site for the evaluation of the frequency and distribution of landslides. Boun is located in the central part of Korea. Landslide-related factors such as slope, soil texture, wood type, lithology, and density of lineament were extracted from topographic, soil, forest, and lineament maps. Landslide locations were identified from interpretation of aerial photographs and field surveys. Landslide-susceptible areas were analyzed by the ANFIS method and mapped using occurrence factors. In particular, we applied various membership functions (MFs) and analysis results were verified using the landslide location data. The predictive maps using triangular, trapezoidal, and polynomial MFs were the best individual MFs for modeling landslide susceptibility maps (84.96% accuracy), proving that ANFIS could be very effective in modeling landslide susceptibility mapping. Various MFs were used in this study, and after verification, the difference in accuracy according to the MFs was small, between 84.81% and 84.96%. The difference was just 0.15% and therefore the choice of MFs was not important in the study. Also, compared with the likelihood ratio model, which showed 84.94%, the accuracy was similar. Thus, the ANFIS could be applied to other study areas with different data and other study methods such as cross-validation. The developed ANFIS learns the if-then rules between landslide-related factors and landslide location for generalization and prediction. It is easy to understand and interpret, therefore it is a good choice for modeling landslide susceptibility mapping, which are also of great help for planners and engineers in selecting highly susceptible areas for further detail surveys and suitable locations to implement development. Although they may be less useful at the site-specific scale, where local geological and geographic heterogeneities may prevail, the results herein may be used as basic data to assist slope management and land use planning. For the method to be more generally applied, more landslide data are needed and more case studies should be conducted.

Lee, S.; Choi, J.; Oh, H.

2009-12-01

 
 
 
 
301

Physically-based modifications to the Sacramento Soil Moisture Accounting model. Part A: Modeling the effects of frozen ground on the runoff generation process  

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This paper presents the first of two physically-based modifications to a widely-used and well-validated hydrologic precipitation-runoff model. Here, we modify the Sacramento Soil Moisture Accounting (SAC-SMA) model to include a physically-based representation of the effects of freezing and thawing soil on the runoff generation process. This model is called the SAC-SMA Heat Transfer model (SAC-HT). The frozen ground physics are taken from the Noah land surface model which serves as the land surface component of several National Center for Environmental Prediction (NCEP) numerical weather prediction models. SAC-HT requires a boundary condition of the soil temperature at the bottom of the soil column (a climatic annual air temperature is typically used, and parameters derived from readily available soil texture data). A noteworthy feature of SAC-HT is that the frozen ground component needs no parameter calibration. SAC-HT was tested at 11 sites in the U.S. for soil temperature, one site in Russia for soil temperature and soil moisture, eight basins in the upper Midwest for the effects of frozen-ground on streamflow, and one location for frost depth. High correlation coefficients for simulated soil temperature at three depths at 11 stations were achieved. Multi-year simulations of soil moisture and soil temperature agreed very well at the Valdai, Russia test location. In eight basins affected by seasonally frozen soil in the upper Midwest, SAC-HT provided improved streamflow simulations compared to SAC-SMA when both models used a priori parameters. Further improvement was gained through calibration of the non-frozen ground a priori parameters. Frost depth computed by SAC-HT compared well with observed values in the Root River basin in Minnesota.

Koren, Victor; Smith, Michael; Cui, Zhengtao

2014-11-01

302

Susceptibility of Shallow Landslide in Fraser Hill Catchment, Pahang Malaysia  

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Full Text Available In tropical areas especially during monsoon seasons intense precipitation is the main caused that trigger the natural shallow landslide phenomena. This phenomenon can be disastrous and widespread in occurrence even in undisturbed forested catchment. In this paper, an attempt has been made to evaluate the susceptibility of natural hill slopes to failure for a popular hill resort area, the Fraser Hill Catchment under different rainfall regimes and soil thickness. A Digital Elevation Model (DEM was prepared for the 8.2 km2 catchment. A GIS based deterministic model was then applied to predict the spatial landslide occurrence within catchment. Model input parameters include bulk density, friction angle, cohesion and hydraulic conductivity were gathered through in situ and lab analysis as well as from previous soil analysis records. Landslides locations were recorded using GPS as well as previous air photos and satellite imagery to establish landslide source areas inventory. The landslide susceptibility map was produced under different precipitation event’s simulation to see the effects of precipitation to stability of the hill slopes of the catchment. The results were categorized into naturally unstable (Defended, Upper Threshold, Lower Threshold, marginal instability (Quasi Stable and stable area (Moderately Stable and Stable. Results of the simulation indicated notable change in precipitation effect on Defended area is between 10mm to 40mm range in a single storm event. However, when storm event is exceeded 120mm, the result on Defended area produced by the model tends to be constant further on. For area categorized as naturally unstable (Factor of Safety, SF<1, with 110 mm of precipitation in a single storm event and soil depth at 2 meters and 4 meters could affect 69.51% and 69.88% respectively of the catchment area fall under that class. In addition, the model was able to detect 4% more of the landslide inventory under shallower soil depth of 2 meters.

Wan Nor Azmin Sulaiman

2010-01-01

303

Soil Enzymes Research: A Review  

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Full Text Available Enzymes are biologically produced proteinic substances having specific activation in which they combine with their substrates in such a stereoscopic position that they cause changes in the electronic configuration around certain susceptible bonds. Their significance in all spheres including soil, is worth tested and reported. In plant nutrition their role cannot be substituted by any other substance and its function is quite pragmatic in solubilizing and dissolving the much needed food in ionic forms for the very survival of animal and plant kingdom. World over, innumerable researchers have contributed their efforts in exploring enzymes. This paper reviews some of the important factors affecting its behaviour, reactions in soil environment, correlation with other enzymes and soil properties, preceded by its historical perspective and sources of production.

Zahir Ahmad Zahir

2001-01-01

304

[The differences of the effects of Vrd1 and Ppd-D1 gene alleles on winterhardiness, frost resistance, and yield in winter wheat].  

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The influence of allelic differences of Vrd1 and Ppd-D1 genes on winterhardiness, frost resistance, yield and its components was studied in recombinant-inbred F5 lines of Odesskaya 16/Bezostaya 1. From 9 to 15% differences in the resistance of recombinant-inbred lines were determined by alternative alleles of Vrd1 gene and 10-16% of Ppd-D1 gene. Interaction of vrd1 and Ppd-D1a alleles led to the higher winterhardiness and frost resistance of tillered plants during the winter. At the same time the significant increase of the period to heading, plant height and the tendency of yield reduction were revealed for vrd1 vrd1 Ppd-D1a Ppd-D1a lines when compared to the lines of Vrd1 Vrd1 Ppd-D1a Ppd-D1a genotype. PMID:19253752

Mokanu, N V; Fa?t, V I

2008-01-01

305

The Relationships Among an Activity of the Alternative Pathway Respiratory Flux, a Content of Carbohydrates and a Frost-Resistance of Winter Wheat  

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Full Text Available A content of carbohydrates and dehydrins in the leaves, activities of the alternative (AP and the cytochrome (CP pathways of respiration in mitochondria, isolated from leaves, during cold hardening continuous light (5 °C and dark conditions with sucrose (2 °C and relationships among these parameters and a frost-resistance of winter wheat have been investigated. The direct relationship among the content of carbohydrates, the activity of AP and frost-resistance of winter wheat has been detected. It has been concluded that the activity of the alternative oxidase during cold hardening of winter wheat depends on the content of soluble carbohydrates and is necessary to maintain metabolic (red/ox homeostasis in the cell at low temperatures.

O.A. Borovik

2013-11-01

306

Snippets from the past: the evolution of Wade Hampton Frost's epidemiology as viewed from the American Journal of Hygiene/Epidemiology.  

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Wade Hampton Frost, who was a Professor of Epidemiology at Johns Hopkins University from 1919 to 1938, spurred the development of epidemiologic methods. His 6 publications in the American Journal of Hygiene, which later became the American Journal of Epidemiology, comprise a 1928 Cutter lecture on a theory of epidemics, a survey-based study of tonsillectomy and immunity to Corynebacterium diphtheriae (1931), 2 papers from a longitudinal study of the incidence of minor respiratory diseases (1933 and 1935), an attack rate ratio analysis of the decline of diphtheria in Baltimore (1936), and a 1936 lecture on the age, time, and cohort analysis of tuberculosis mortality. These 6 American Journal of Hygiene /American Journal of Epidemiology papers attest that Frost's personal evolution mirrored that of the emerging "early" epidemiology: The scope of epidemiology extended beyond the study of epidemics of acute infectious diseases, and rigorous comparative study designs and their associated quantitative methods came to light. PMID:24022889

Morabia, Alfredo

2013-10-01

307

Contribution to the edaphic components definition in the desertification susceptibility index  

International Nuclear Information System (INIS)

Many of the biophysical processes involved in the scope of desertification depend on the hydric characteristics of the soils the impact on vegetation cover. To protect soils against desertification, it is necessary to understand how some of these characteristics (such as water storage) interact in a complex and integrated chain of degradation processes. Several works have been developed to contribute to the definition of a Index of Desertification Susceptibility (DSI) expressed as a function of several components, climatic, edaphic, vegetative and slope. However, the various built-in edaphic components already defined, leave aside the water retention in soil. Furthermore, these components only focus on the characteristics of the uppermost surface soil layer (A-layer). In fact, desertification is simultaneously cause and consequence of the depleted soil water retention with a positive feedback of the plant life and on the hydrological cycle. (Author) 10 refs.

308

Genetic susceptibility to childhood leukaemia  

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The aetiology of leukaemias among children is believed to be distinct from that of adults, mainly due to the clearer role for early life exposures, including those in utero. However, few risk factors have been established, because of the challenge of studying a disease with relatively low incidence. Identified risk factors, including ionizing radiation, chemotherapeutic agents and specific genetic abnormalities, explain <10% of incidence. Although the causes for the remaining 90% are unknown, it is possible that genetic susceptibility factors, either alone or in conjunction with environmental factors, may be involved. In this paper, the authors (a) review the evidence surrounding genetic susceptibility factors, with emphasis on the genes' main effects; (b) review some recent developments in the Northern California Childhood Leukaemia Study (NCCLS) as a case study of design and practical considerations in genetic epidemiology research and (c) highlight both challenges and future directions in this exciting research area. (authors)

309

AC susceptibility study of YBCO  

Science.gov (United States)

The temperature dependence of ac susceptibility of YBCO bulk samples was measured as a function of ac field amplitude and frequency. Analysis of the temperature dependence of the ac susceptibility near the transition temperature ( T c ) has been done employing the simplified Kim model. We have obtained an empirical function for the penetration field H p = H ? (1- t) ? , t = T= T c . Best fitting to data was obtained with parameters H ? ? 6:2 × 103 A/m and ? ? 1.50. The experimental value agrees well with the model calculations. In addition, as the frequency increases, the peak temperature ( T p ) shifts to higher temperature. This effect can be interpreted in terms of flux creep. The field dependence of activation energy obtained from the Arrhenius plots for the frequency ( f) and ( T p ) can be described as U ? ( H ac )- ?' with ?' ? 0:38 for YBCO.

Güçlü, N.; Kölemen, U.

2011-09-01

310

Genetic susceptibility to Candida infections.  

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Candida spp. are medically important fungi causing severe mucosal and life-threatening invasive infections, especially in immunocompromised hosts. However, not all individuals at risk develop Candida infections, and it is believed that genetic variation plays an important role in host susceptibility. On the one hand, severe fungal infections are associated with monogenic primary immunodeficiencies such as defects in STAT1, STAT3 or CARD9, recently discovered as novel clinical entities. On the other hand, more common polymorphisms in genes of the immune system have also been associated with fungal infections such as recurrent vulvovaginal candidiasis and candidemia. The discovery of the genetic susceptibility to Candida infections can lead to a better understanding of the pathogenesis of the disease, as well as to the design of novel immunotherapeutic strategies. This review is part of the review series on host-pathogen interactions. See more reviews from this series. PMID:23629947

Smeekens, Sanne P; van de Veerdonk, Frank L; Kullberg, Bart Jan; Netea, Mihai G

2013-06-01

311

Association analysis of frost tolerance in rye using candidate genes and phenotypic data from controlled, semi-controlled, and field phenotyping platforms  

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Full Text Available Abstract Background Frost is an important abiotic stress that limits cereal production in the temperate zone. As the most frost tolerant small grain cereal, rye (Secale cereale L. is an ideal cereal model for investigating the genetic basis of frost tolerance (FT, a complex trait with polygenic inheritance. Using 201 genotypes from five Eastern and Middle European winter rye populations, this study reports a multi-platform candidate gene-based association analysis in rye using 161 single nucleotide polymorphisms (SNPs and nine insertion-deletion (Indel polymorphisms previously identified from twelve candidate genes with a putative role in the frost responsive network. Results Phenotypic data analyses of FT in three different phenotyping platforms, controlled, semi-controlled and field, revealed significant genetic variations in the plant material under study. Statistically significant (P ScCbf15 and one in ScCbf12, all leading to amino acid exchanges, were significantly associated with FT over all three phenotyping platforms. Distribution of SNP effect sizes expressed as percentage of the genetic variance explained by individual SNPs was highly skewed towards zero with a few SNPs obtaining large effects. Two-way epistasis was found between 14 pairs of candidate genes. Relatively low to medium empirical correlations of SNP-FT associations were observed across the three platforms underlining the need for multi-level experimentation for dissecting complex associations between genotypes and FT in rye. Conclusions Candidate gene based-association studies are a powerful tool for investigating the genetic basis of FT in rye. Results of this study support the findings of bi-parental linkage mapping and expression studies that the Cbf gene family plays an essential role in FT.

Li Yongle

2011-10-01

312

Influence of cosistency, air entraining agent and moist curing period on salt-frost scaling resistance of concrete with higher content of limestone filer  

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The aim of the diploma work was to examine resistance of self-compacting and control vibrated concrete to the salt frost scaling. Self-compacting concrete (SCC) contained limestone powder as additional fine material. The highest number of experimental tests was made on aerated SCC mixtures with air content of 8%. Control concrete mixtures were non- aerated SCC, aerated vibrated concretes, with and without additional limestone powder, as well as non-aerated vibrated concretes, also with and wi...

Z?nidars?ic?, Mitja

2007-01-01

313

A GIS analysis of the relationship between sinkholes, dry-well complaints and groundwater pumping for frost-freeze protection of winter strawberry production in Florida.  

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Florida is riddled with sinkholes due to its karst topography. Sometimes these sinkholes can cause extensive damage to infrastructure and homes. It has been suggested that agricultural practices, such as sprinkler irrigation methods used to protect crops, can increase the development of sinkholes, particularly when temperatures drop below freezing, causing groundwater levels to drop quickly during groundwater pumping. In the strawberry growing region, Dover/Plant City, Florida, the effects have caused water shortages resulting in dry-wells and ground subsidence through the development of sinkholes that can be costly to maintain and repair. In this study, we look at how frost-freeze events have affected West Central Florida over the past 25 years with detailed comparisons made between two cold-years (with severe frost-freeze events) and a warm year (no frost-freeze events). We analyzed the spatial and temporal correlation between strawberry farming freeze protection practices and the development of sinkholes/dry well complaints, and assessed the economic impact of such events from a water management perspective by evaluating the cost of repairing and drilling new wells and how these compared with using alternative crop-protection methods. We found that the spatial distribution of sinkholes was non-random during both frost-freeze events. A strong correlation between sinkhole occurrence and water extraction and minimum temperatures was found. Furthermore as temperatures fall below 41°F and water levels decrease by more than 20 ft, the number of sinkholes increase greatly (N >10). At this time alternative protection methods such as freeze-cloth are cost prohibitive in comparison to repairing dry wells. In conclusion, the findings from this study are applicable in other agricultural areas and can be used to develop comprehensive water management plans in areas where the abstraction of large quantities of water occur. PMID:23326518

Aurit, Mark D; Peterson, Robert O; Blanford, Justine I

2013-01-01

314

Transgenic mice susceptible to poliovirus.  

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Poliovirus-sensitive transgenic mice were produced by introducing the human gene encoding cellular receptors for poliovirus into the mouse genome. Expression of the receptor mRNAs in tissues of the transgenic mice was analyzed by using RNA blot hybridization and the polymerase chain reaction. The human gene is expressed in many tissues of the transgenic mice just as in tissues of humans. The transgenic mice are susceptible to all three poliovirus serotypes, and the mice inoculated with poliov...

Koike, S.; Taya, C.; Kurata, T.; Abe, S.; Ise, I.; Yonekawa, H.; Nomoto, A.

1991-01-01

315

Antimicrobial susceptibility of Haemophilus ducreyi.  

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The susceptibility of 19 isolates of Haemophilus ducreyi from a recent chancroid outbreak and four reference strains was determined in vitro to 13 antimicrobial agents. The rabbit intradermal test for virulence was positive for all of the local isolates, but not for the reference strains. The “nonvirulent” reference strains were inhibited by lower minimum inhibitory concentrations (MICs) of most agents tested. For the virulent isolates, the range of MICs (in micrograms per milliliter) of ...

Dangor, Y.; Ballard, R. C.; Miller, S. D.; Koornhof, H. J.

1990-01-01

316

Developmental reprogramming of cancer susceptibility  

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Gene–environment interactions have been traditionally understood to promote the acquisition of mutations that drive multistage carcinogenesis, and, in the case of inherited defects in tumour suppressor genes, additional mutations are required for cancer development. However, the developmental origins of health and disease (DOHAD) hypothesis provides an alternative model whereby environmental exposures during development increase susceptibility to cancer in adulthood, not by inducing genetic...

Walker, Cheryl Lyn; Ho, Shuk-mei

2012-01-01

317

Tuberculosis Susceptibility of Diabetic Mice  

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Increased susceptibility to infections, including tuberculosis (TB), is a major cause of morbidity and mortality in patients with diabetes. Despite the clinical importance of this problem, little is known about how diabetes impairs protective immunity. We modeled this phenomenon by infecting acute (? 1 mo) or chronic (? 3 mo) diabetic mice with a low aerosol dose of Mycobacterium tuberculosis (Mtb) Erdman. Diabetes was induced by streptozotocin (STZ) treatment of C57BL/6 mice, while anoth...

Martens, Gregory W.; Arikan, Meltem Cevik; Lee, Jinhee; Ren, Fucheng; Greiner, Dale; Kornfeld, Hardy

2007-01-01

318

Antibiotic susceptibility of Atopobium vaginae  

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Full Text Available Abstract Background Previous studies have indicated that a recently described anaerobic bacterium, Atopobium vaginae is associated with bacterial vaginosis (BV. Thus far the four isolates of this fastidious micro-organism were found to be highly resistant to metronidazole and susceptible for clindamycin, two antibiotics preferred for the treatment of BV. Methods Nine strains of Atopobium vaginae, four strains of Gardnerella vaginalis, two strains of Lactobacillus iners and one strain each of Bifidobacterium breve, B. longum, L. crispatus, L. gasseri and L. jensenii were tested against 15 antimicrobial agents using the Etest. Results All nine strains of A. vaginae were highly resistant to nalidixic acid and colistin while being inhibited by low concentrations of clindamycin (range: G. vaginalis strains were also susceptible for clindamycin ( 256 ?g/ml but susceptible to clindamycin (0.023 – 0.125 ?g/ml. Conclusion Clindamycin has higher activity against G. vaginalis and A. vaginae than metronidazole, but not all A. vaginae isolates are metronidazole resistant, as seemed to be a straightforward conclusion from previous studies on a more limited number of strains.

Verschraegen Gerda

2006-03-01

319

Development of Paving Material for Footpath and CAR Park Pavement Using Granite Soil  

Science.gov (United States)

It is required to develop new paving materials for pavements, such as footpaths, car parks, etc., in parks, having good landscape. Such paving materials have been already developed, but these do not have sufficient strength, abrasion resistance and frost resistance. In this study, a new paving was examined material using cement, sand and granite soil. The mix proportion of this material tested was 2:4:4 of cement, sand and granite soil by mass. The maximum flexural and compressive strength were both obtained at a water content of 14% of the total mass, and the strength were several times larger than that of paving material on the market consisting of 10% of cement and 90% granite soil. The abrasion resistance was tested according to ASTM C 779, and this resistance was about four times greater than that of the paving material on the market. The frost resistance was obtained high value compared with the concrete of 72% in water cement ratio by a new simple resisting test method for freezing and thawing using liquid nitrogen and warm water. It is considered that this new paving material is applicable to pavement for footpath, car park, etc.

Nagamachi, Masaharu; Mizuguchi, Hiroyuki; Inoue, Kentaro; Kamada, Koichi

320

Influencia de 46 porta-injertos para cítricos en la precocidad o retardo de maduración de la naranja "Frost valencia" (Citrus sinensis (L. Osbeck  

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Full Text Available Of 46 graft carrier influence in citrics on ripe precocity or retardation from "Frost Valencia" Citrus sinensis (L Osbeck was studied looking for to guaranter a fruit constant supply toward market. Graft carrier influence was tested in orange blosson, fruiting ripeness season. Stock influence to induce early intermediate or later blossoms was observed, related with period and intensity so them same ocurr. Stock influence on solubles solids content, juici volume, ripeness index, ripe fruit, mantenence on tree also was found . Early of later yields are feasible to obtain using trifoliado x Ruby Or (1437 and "Garcia Valencia" stock markedly, or which highly significant ripeness gains were found with "Frost Valencia" Orange respectively.Se estudió la influencia de los portainjertos para cítricos buscando la obtención de producciones tempranas o tardías para garantizar un suministro continuo de fruta fresca al mercado. Se analizó por espacio de dos años la influencia de los porta-injertos en el período de floración, fructificación y maduración de la naranja. Se observó influencia del patrón para inducir floraciones precoces, intermedias o tardías haciendo referencia al período de intensidad con que ocurren las mismas. También se encontró influencia del patrón en contenido de sólidos solubles, volumen de jugo, acidez, índice de marez y mantenimiento de la fruta madura en el árbol. Es posible obtener producciones tempranas o tardías con la utilización de los patrones trifoliados x Ruby Or (1437 Y García Valencia, sobre las cuales se encontró adelantos altamente significativos de maduración de la naranja "Frost Valencia" respectivamente.

Caselles N. Álvaro A.

1987-03-01

 
 
 
 
321

Far-UV, visible, and near-IR reflectance spectra of frosts of H2O, CO2, NH3 and SO2  

Science.gov (United States)

Measurements in the 0.1-2.5 micron range are presented for the reflectance spectra of the frosts of several volatiles pertinent to the study of comet nuclei. The frost spectra have distinctive features permitting their identification by spectroscopic reflectance remote sensing, notably in the far UV. It is found that: (1) H2O has a minimum at 0.16 microns and a maximum at 0.13 microns; (2) CO2 has minima near 0.21, 0.18 and 0.125 microns, with maxima at 0.19, 0.135 and 0.120 microns; (3) NH3 is bright at wavelengths longer than 0.21 microns, where reflectance drops to a value of only a few per cent at shorter wavelengths; (4) SO2 has a sharp drop at 0.32 microns, with a minimum at 0.18 microns and a maximum at 0.13 microns. The features in the frost spectra largely correspond to absorption line bands in the gas phase.

Hapke, B.; Wells, E.; Wagner, J.; Partlow, W.

1981-01-01

322

Combined landslide inventory and susceptibility assessment based on different mapping units: an example from the Flemish Ardennes, Belgium  

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For a 277 km2 study area in the Flemish Ardennes, Belgium, a landslide inventory and two landslide susceptibility zonations were combined to obtain an optimal landslide susceptibility assessment, in five classes. For the experiment, a regional landslide inventory, a 10 m × 10 m digital representation of topography, and lithological and soil hydrological information obtained from 1:50 000 scale maps, were exploited. In the study area, the regional inventory sho...

Den Eeckhaut, M.; Reichenbach, P.; Guzzetti, F.; Rossi, M.; Poesen, J.

2009-01-01

323

Effect of Heterodera glycines on Charcoal Rot Severity in Soybean Cultivars Resistant and Susceptible to Soybean Cyst Nematode  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Field experiments were conducted in two soil types in northeastern Kansas to evaluate the influence of Heterodera glycines on the severity of charcoal rot in group III soybean cultivars resistant and susceptible to soybean cyst nematode race 3. Resistant cultivars Asgrow 3307 and Fayette and susceptible cultivars Asgrow 3127, Harper, Pella, Sprite, and Williams 82 were planted in carbofuran-treated and nontreated plots. Heterodera glycines and the charcoal rot fungus, Macrophomina phaseolina,...

Todd, T. C.; Pearson, C. A. S.; Schwenk, F. W.

1987-01-01

324

Fungal communities associated with degradation of polyester polyurethane in soil.  

Science.gov (United States)

Soil fungal communities involved in the biodegradation of polyester polyurethane (PU) were investigated. PU coupons were buried in two sandy loam soils with different levels of organic carbon: one was acidic (pH 5.5), and the other was more neutral (pH 6.7). After 5 months of burial, the fungal communities on the surface of the PU were compared with the native soil communities using culture-based and molecular techniques. Putative PU-degrading fungi were common in both soils, as Phoma sp. were the dominant species recovered by culturing from the PU buried in the acidic and neutral soils, respectively. Both fungi degraded Impranil and represented >80% of cultivable colonies from each plastic. However, PU was highly susceptible to degradation in both soils, losing up to 95% of its tensile strength. Therefore, different fungi are associated with PU degradation in different soils but the physical process is independent of soil type. PMID:17660302

Cosgrove, Lee; McGeechan, Paula L; Robson, Geoff D; Handley, Pauline S

2007-09-01

325

CFD Assessment of Forward Booster Separation Motor Ignition Overpressure on ET XT 718 Ice/Frost Ramp  

Science.gov (United States)

Computational fluid dynamics assessment of the forward booster separation motor ignition over-pressure was performed on the space shuttle external tank X(sub T) 718 ice/frost ramp using the flow solver OVERFLOW. The main objective of this study was the investigation of the over-pressure during solid rocket booster separation and its affect on the local pressure and air-load environments. Delta pressure and plume impingement were investigated as a possible contributing factor to the cause of the debris loss on shuttle missions STS-125 and STS-127. A simplified computational model of the Space Shuttle Launch Vehicle was developed consisting of just the external tank and the solid rocket boosters with separation motor nozzles and plumes. The simplified model was validated by comparison to full fidelity computational model of the Space Shuttle without the separation motors. Quasi steady-state plume solutions were used to calibrate the thrust of the separation motors. Time-accurate simulations of the firing of the booster-separation motors were performed. Parametric studies of the time-step size and the number of sub-iterations were used to find the best converged solution. The computed solutions were compared to previous OVERFLOW steady-state runs of the separation motors with reaction control system jets and to ground test data. The results indicated that delta pressure from the overpressure was small and within design limits, and thus was unlikely to have contributed to the foam losses.

Tejnil, Edward; Rogers, Stuart E.

2012-01-01

326

Soil suction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Suction is pore water pressure in unsaturated soils and influences other soil characteristics. Suction measurements for 4 different soils (bentonite, stone flour, gray clay “sivica” and brown clay “flysch”) are presented. Measurements were performed on compacted and loose material at different water contents using 4 different methods: WP4 dewpoint potentiometer, filter paper, tenziometer and pressure plate apparatus. Additionally the water adsorption was determined for ...

Mac?ek, Matej

2006-01-01

327

A LANDSLIDE SUSCEPTIBILITY ANALYSIS FOR BUZAU COUNTY, ROMANIA  

Directory of Open Access Journals (Sweden)

Full Text Available Landslides are one of the most common hazards in the Romanian Curvature Carpathians and Subcarpathians, covering a wide range of geomorphic mass wasting forms and processes. The purpose of this paper is to present a susceptibility analysis at regional scale for the Buzau County (Romania, focusing on shallow and medium-seated (sensu B?lteanu 1983 landslides. The susceptibility map was obtained using the weights-ofevidence modeling technique that allows understanding the significance of predisposing factors of shallow and medium-seated failures. The model was run considering eight environmental factors: slope, altitude, internal relief, planar and profile curvature, aspect, soil, land-use. A landslide inventory derived from archive data, literature review, field mapping and aerial imagery interpretation was divided into a training and a prediction set and was used to prepare and validate the model. The model performance was evaluated using the area under the ROC and the success rate curve. The susceptibility map represents an important step for landslide hazard and risk assessment, crucial components for the definition of adequate risk management strategies.

VERONICA ZUMPANO

2014-06-01

328

Resistência inicial de quatro espécies arbóreas em diferentes espaçamentos após ocorrência de geada / Initial resistance of four arboreal species in different spacing after frost occurrence  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A ocorrência de geada, dependendo do grau de dano, pode se tornar um fator limitante para a condução de florestas de curta rotação. O presente trabalho teve como objetivo avaliar o comportamento após ocorrências de geadas das espécies florestais Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex [...] Maiden, Mimosa scabrella Benth e Ateleia glazioveana Baill submetidas a níveis de espaçamento de 2,0x1,0m; 2,0x1,5m; 3,0x1,0 e 3,0x1,5m um ano após o plantio, na região Norte do Rio Grande do Sul. Os danos (resistência a geada) foram avaliados segundo o sistema de notas de 0 a 10, conforme a intensidade do dano na planta. Os graus de resistência à geada foram determinados em função da intensidade do dano na planta. Os níveis de espaçamento estudados não afetaram respostas das espécies em relação ao dano ocasionado por geada. A espécie Mimosa scabrella apresentou ser resistente, enquanto que Eucalyptus grandis e Ateleia glazioveana, tolerantes. Já a Acacia mearnsii apresentou ser moderadamente tolerante a tolerante. Abstract in english The frost occurrence depending on the damage degree, can become a limit factor for the transport of forests of short rotation. The present research has as objective evaluate the behavior after occurrences of frosts of the species forest Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex Maiden, [...] Mimosa scabrella Benth and Ateleia glazioveana Baill were submitted to levels of spacing of 2.0 x 1.0m; 2.0x1.5m; 3.0x1.0m and 3.0x1.5m one year after the planting, in the North of Rio Grande do Sul. The damages (resistance to frost) were appraised according to scale 0 to 10 according to the intensity of the damage in the plant. The frost resistance degrees were certain in function of the intensity of the damage in the plant. The spacing levels studied didn't affect the species answers in relation to the damage caused by frost. The species Mimosa scabrella presented to be resistant, while Eucalyptus grandis and Ateleia glazioveana tolerant. Already the Acacia mearnsii was moderately tolerant to tolerant.

Braulio Otomar, Caron; Velci Queiróz de, Souza; Elder, Eloy; Alexandre, Behling; Denise, Schmidt; Rômulo, Trevisan.

2011-05-01

329

Impacts of soil erosion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

3.1 Definition of soil functions, soil quality and quality targets The identification of soil functions, properties and processes which are affected by soil erosion is needed to evaluate the impacts of erosion on the soil system. Definition of soil loss tolerance according to soil types and environmental characteristics. 3.2 Development of criteria and indicators to assess soil sustainable use and soil protection measures What are the impacts of soil erosion on soil...

Dorren, Luuk; La Rosa, Diego; Theocharopoulos, Sid P.

2004-01-01

330

Use of Satellite Remote Sensing Data in the Mapping of Global Landslide Susceptibility  

Science.gov (United States)

Satellite remote sensing data has significant potential use in analysis of natural hazards such as landslides. Relying on the recent advances in satellite remote sensing and geographic information system (GIS) techniques, this paper aims to map landslide susceptibility over most of the globe using a GIs-based weighted linear combination method. First , six relevant landslide-controlling factors are derived from geospatial remote sensing data and coded into a GIS system. Next, continuous susceptibility values from low to high are assigned to each of the six factors. Second, a continuous scale of a global landslide susceptibility index is derived using GIS weighted linear combination based on each factor's relative significance to the process of landslide occurrence (e.g., slope is the most important factor, soil types and soil texture are also primary-level parameters, while elevation, land cover types, and drainage density are secondary in importance). Finally, the continuous index map is further classified into six susceptibility categories. Results show the hot spots of landslide-prone regions include the Pacific Rim, the Himalayas and South Asia, Rocky Mountains, Appalachian Mountains, Alps, and parts of the Middle East and Africa. India, China, Nepal, Japan, the USA, and Peru are shown to have landslide-prone areas. This first-cut global landslide susceptibility map forms a starting point to provide a global view of landslide risks and may be used in conjunction with satellite-based precipitation information to potentially detect areas with significant landslide potential due to heavy rainfall. 1

Hong, Yang; Adler, Robert F.; Huffman, George J.

2007-01-01

331

Shallow soil moisture – ground thaw interactions and controls – Part 2: Influences of water and energy fluxes  

Directory of Open Access Journals (Sweden)

Full Text Available The companion paper (Guan et al., 2010 demonstrated variable interactions and correlations between shallow soil moisture and ground thaw in soil filled areas along a wetness spectrum in a subarctic Canadian Precambrian Shield landscape. From wetter to drier, these included a wetland, peatland and soil filled valley. Herein, water and energy fluxes were examined for these same subarctic study sites to discern the key controlling processes on the found patterns. Results showed the presence of surface water was the key control in variable soil moisture and frost table interactions among sites. At the peatland and wetland sites, accumulated water in depressions and flow paths maintained soil moisture for a longer duration than at the hummock tops. These wet areas were often locations of deepest thaw depth due to the transfer of latent heat accompanying lateral surface runoff. Although the peatland and wetland sites had large inundation extent, modified Péclet numbers indicated the relative influence of external and internal hydrological and energy processes at each site were different. Continuous inflow from an upstream lake into the wetland site caused advective and conductive thermal energies to be of equal importance to ground thaw. The absence of continuous surface flow at the peatland and valley sites led to dominance of conductive thermal energy over advective energy for ground thaw. The results suggest that the modified Péclet number could be a very useful parameter to differentiate landscape components in modeling frost table heterogeneity. The calculated water and energy fluxes, and the modified Péclet number provide quantitative explanations for the shallow soil moisture-ground thaw patterns by linking them with hydrological processes and hillslope storage capacity.

X. J. Guan

2010-07-01

332

Soils electroremediation  

International Nuclear Information System (INIS)

This paper presents data on decontamination experiments performed with soils contaminated by long-lived radioactive caesium isotopes. The contamination was formed about 30 years ago during an accident in the first nuclear power station in the former Czechoslovakia. Because of the large soil quantities that make excavation and storage of these soils in nuclear waste repositories inconvenient from economical and spatial point of view, various methods for in situ or ex situ remediation were sought and tested. For soil contamination by caesium, the time of contact of caesium with the soil is crucial because the caesium ions diffuse inside the crystalline structures of clay minerals where they are virtually irreversibly bound. For such materials, the efficiency of the classic 'soft' decontamination methods, such as leaching, phytoremediation etc., is rather low. Electrochemical decontamination was proposed as the decontamination technique for ex situ application. The method is based on electrolysis at a relatively high current density in a suitable electrolyte. The soil is kept in suspension close to the anode, and owing to the high acidity together with both the high temperature and ion flux, the soil structures are opened or partially disrupted and caesium ions are released. The ions can be separated from the solution, e.g., by using selective ion exchangers. The experimental electrolytic cell was designed for the treatment of thin soil layers containing about 3 g of thein soil layers containing about 3 g of the soil and about 100 mL of electrolyte. The influence of various system parameters, such as electrolyte composition, current-voltage, temperature, and time, on the decontamination efficiency was examined. In the most efficient configuration, a 99+% decontamination level was achieved. For the next step, a bench-scale apparatus was designed that should allow treatment of batches of up to 0.5 kg of soil in one step. (author)

333

Soil Science Education for Primary and Secondary Students  

Science.gov (United States)

Soils is one of the science investigation areas in the Global learning and Observations to Benefit the Environment (GLOBE), an international science and education program (112 countries) that teaches primary and secondary students to learn science by doing science. For each area of investigation GLOBE provides background information, measurement protocols and learning activities compiled as a chapter in the GLOBE Teacher's Guide. Also provided are data sheets and field guides to assist in the accurate collection of data as well as suggestions of scientific instruments and calibration methods. Teachers learn GLOBE scientific measurement protocols at professional development workshops led by scientists and educators, who then engage their students in soil studies that also contribute to ongoing science investigations. Students enter their data on the GLOBE website and can access their data as well as other data contributed by students from other parts of the world. Soil characterization measurements carried out in the field include site description, horizon depths, soil structure, soil color, soil consistence, soil texture, roots, rocks and carbonates. Other field measurements are soil temperature and soil moisture monitoring while the following measurements are carried out in the classroom or laboratory: gravimetric soil moisture, bulk density, particle density, particle size distribution, pH and soil fertility (nitrogen, phosphorus and potassium). Learning activities provide support for preparing students to do the measurements and for better understanding of science concepts. Many countries in GLOBE have adopted standards for education including science education with commonalities among them. For the Teacher's Guide, the National Science Education Standards published by the US National Academy of Sciences, selected additional content standards that GLOBE scientists and educators feel are appropriate and the National Geography Standards prepared by the (US) National Education Standards Project, are being used. Educational objectives for students include gaining scientific inquiry abilities in addition to understanding scientific concepts. The Soils chapter also includes some suggestions for managing students in the field and classroom. A new protocol has also been developed by the Seasons and Biomes project, one of the GLOBE earth system science projects. Active Layer monitoring uses a Frost Tube that measures when and how deeply soil freezes and is currently being used in more than 200 sites in Alaska. Teachers have successfully implemented soil studies in their curriculum and have used it to teach about the science process.

Sparrow, Elena; Yoshikawa, Kenji; Kopplin, Martha

2013-04-01

334

Colloid Release From Differently Managed Loess Soil  

DEFF Research Database (Denmark)

The content of water-dispersible colloids (WDC) in a soil can have a major impact on soil functions, such as permeability to water and air, and on soil strength, which can impair soil fertility and workability. In addition, the content of WDC in the soil may increase the risk of nutrient loss and of colloid-facilitated transport of strongly sorbing compounds. In the present study, soils from the Bad Lauchstädt long-term static fertilizer experiment with different management histories were investigated to relate basic soil properties to the content of WDC, the content of water-stable aggregates (WSA), and aggregate tensile strength. Our studies were carried out on soils on identical parent material under controlled management conditions, enabling us to study the long-term effects on soil physical properties with few explanatory variables in play. The content of WDC and the amount of WSA were measured at a series of time steps giving a colloid release and aggregate disaggregation rate and a quantification of the content of WDC and WSA at a given time for each of the six investigated experimental field plots. The content of WDC in the moist soil was linearly correlated (r = 0.82* [P < 0.05]) to the part of the total clay not associated with organic matter. No significant difference in release rate was found for air-dry aggregates. The low-carbon soils initially had a higher content of WSA but were more susceptible to disaggregation than the high-carbon soils. Furthermore, the application of NPK fertilizer had a destabilizing effect on the WSA and also caused a decrease in the cation exchange capacity of the soils. The mean tensile strength was positively correlated to the colloid release rate and the content of WDC after 2 min of shaking and therefore to the amount of clay not associated with organic carbon.

Vendelboe, Anders Lindblad; SchjØnning, Per

2012-01-01

335

Susceptibility of the strawberry crown moth (Lepidoptera: Sesiidae) to entomopathogenic nematodes.  

Science.gov (United States)

The objective of this study was to determine the susceptibility of the strawberry crown moth, Synanthedon bibionipennis (Boisduval) (Lepidoptera: Sesiidae) larvae to two species of entomopathogenic nematodes. The entomopathogenic nematodes Steinernema carpocapsae (Weiser) strain Agriotos and Heterorhabditis bacteriophora (Steiner) strain Oswego were evaluated in laboratory soil bioassays and the field. Both nematode species were highly infective in the laboratory bioassays. Last instars were extremely susceptible to nematode infection in the laboratory, even in the protected environment inside the strawberry (Fragaria x ananassa Duch.) crown. Infectivity in the laboratory was 96 and 94% for S. carpocapsae and H. bacteriophora, respectively. Field applications in late fall (October) were less effective with S. carpocapsae and H. bacteriophora, resulting in 51 and 33% infection, respectively. Larval mortality in the field from both nematode treatments was significantly greater than the control, but treatments were substantially less efficacious than in the laboratory. Soil temperature after nematode applications in the field (11 degrees C mean daily temperature) was below minimum establishment temperatures for both nematode species for a majority of the post-application period. It is clear from laboratory data that strawberry crown moth larvae are extremely susceptible to nematode infection. Improved control in the field is likely if nematode applications are made in late summer to early fall when larvae are present in the soil and soil temperatures are more favorable for nematode infection. PMID:18459385

Bruck, Denny J; Edwards, David L; Donahue, Kelly M

2008-04-01

336

Soil structure and microbial activity dynamics in 20-month field-incubated organic-amended soils  

DEFF Research Database (Denmark)

Soil structure formation is essential to all soil ecosystem functions and services. This study aims to quantify changes in soil structure and microbial activity during and after field incubation and examine the effect of carbon, organic amendment and clay on aggregate characteristics. Five soils dominated by illites, one kaolinitic soil and one smectitic soil were sieved to 2?mm, and each soil was divided into two parts and one part amended with ground rape shoots (7.5?t?ha?1) as an organic amendment. Samples were incubated in the field for 20?months with periodic sampling to measure water-dispersible clay (WDC) and fluorescein diacetate activity (FDA). After incubation, WDC and FDA were measured on air-dried 1–2-mm aggregates. Tensile strength was measured on four aggregate classes (1–2, 1–4, 4–8 and 8–16?mm) and results used to assess soil friability and workability. Intact cores were also sampled to determine compressive strength. During incubation, the amount of WDC depended on soil carbon content while the trends correlated with moisture content. Organic amendment only yielded modest decreases (mean of 14% across all sampling times and soils) in WDC, but it was sufficient to stimulate the microbial community (65–100% increase in FDA). Incubation led to significant macroaggregate formation (>2?mm) for all soils. Friability and strength of newly-formed aggregates were negatively correlated with clay content and carbon content, respectively. Soil workability was best for the kaolinite-rich soil and poorest for the smectite-rich soil; for illitic soils, workability increased with increasing organic carbon content. Organic amendment decreased the compression susceptibility of intact, incubated samples at smaller stress values (<200?kPa).

Arthur, Emmanuel; SchjØnning, Per

2014-01-01

337

Topological susceptibility from the overlap  

DEFF Research Database (Denmark)

The chiral symmetry at finite lattice spacing of Ginsparg-Wilson fermionic actions constrains the renormalization of the lattice operators; in particular, the topological susceptibility does not require any renormalization, when using a fermionic estimator to define the topological charge. Therefore, the overlap formalism appears as an appealing candidate to study the continuum limit of the topological susceptibility while keeping the systematic errors under theoretical control. We present results for the SU(3) pure gauge theory using the index of the overlap Dirac operator to study the topology of the gauge configurations. The topological charge is obtained from the zero modes of the overlap and using a new algorithm for the spectral flow analysis. A detailed comparison with cooling techniques is presented. Particular care is taken in assessing the systematic errors. Relatively high statistics (500 to 1000 independent configurations) yield an extrapolated continuum limit with errors that are comparable with other methods. Our current value from the overlap is $\\chi^{1/4} = 188 \\pm 12 \\pm 5 \\MeV$.

Del Debbio, Luigi; Pica, Claudio

2003-01-01

338

Arctic organic aerosol measurements show particles from mixed combustion in spring haze and from frost flowers in winter  

Science.gov (United States)

Submicron atmospheric aerosol particles were collected between 1 March 2008 and 1 March 2009 at Barrow, Alaska, to characterize the organic mass (OM) in the Arctic aerosol. Organic functional group concentrations and trace metals were measured with FTIR on submicron particles collected on Teflon filters. The OM varied from 0.07 ?g m-3 in summer to 0.43 ?g m-3 in winter, and 0.35 ?g m-3 in spring, showing a transition in OM composition between spring and winter. Most of the OM in spring could be attributed to anthropogenic sources, consisting primarily of alkane and carboxylic acid functional groups and correlated to elemental tracers of industrial pollution, biomass burning, and shipping emissions. PMF analysis associated OM with two factors, a Mixed Combustion factor (MCF) and an Ocean-derived factor (ODF). Back trajectory analysis revealed that the highest fractions of the MCF were associated with air masses that had originated from northeastern Asia and the shipping lanes south of the Bering Straits. The ODF consisted of organic hydroxyl groups and correlated with organic and inorganic seawater components. The ODF accounted for more than 55% of OM in winter when the sampled air masses originated along the coastal and lake regions of the Northwest Territories of Canada. Frost flowers with organic-salt coatings that arise by brine rejection during sea ice formation may account for this large source of carbohydrate-like OM during the ice-covered winter season. While the anthropogenic sources contributed more than 0.3 ?g m-3 of the springtime haze OM, ocean-derived particles provided comparable OM sources in winter.

Shaw, P. M.; Russell, L. M.; Jefferson, A.; Quinn, P. K.

2010-05-01

339

Comparing temporal and spatial change of pore water pressure and slope stability between wet soil condition and unsaturated soil condition  

Science.gov (United States)

Intense rainfall event during short duration is the most significant reason of landslide in South Korea. Typically, it increases pore water pressure in soil and reduces soil effective stress, which cause landslide. In rainfall-induced landslide, saturation rate of soil at initial condition can affect whether landslide occurs. The objective of this study is to compare temporal and spatial pore water pressure and slope stability between in wet soil and in unsaturated soil under same rainfall condition. Two different infiltration models of TRIGRS 2 (Fortran Program for Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis) were employed to analyze difference of pore water pressure and soil stability under different soil initial conditions. The study site was two small watersheds of Mt. Umyeon in South Korea, where several landslides occurred under an extreme rainfall event on July 27, 2011. Topographical data were generated based on 1 m x 1 m-LiDAR data, and parameters of soil and water characteristics were measured in-situ for TRIGRS 2 simulation. In addition, soil water characteristic curve of the site for the unsaturated soil condition was estimated by the pressure plate method and the filter paper method. The simulation results showed that pore water pressure differently responded between the different water conditions of soil. Ground water table rise appeared relatively faster and higher in the wet soil condition than in the unsaturated soil condition. Moreover, in the wet soil condition, pore water pressure increased with depth while in the unsaturated soil condition, vertical distribution of pore water pressure varied in time. In terms of slope stability, lower factor of safety (FS) were estimated in the wet soil condition than in the unsaturated soil condition. Comparing with landslide initiation positions in reality, FS were calculated more reasonably in the wet soil condition while FS were under-estimated in the unsaturated soil condition. These results indicate that estimating accurate initial water condition of landslide site is important for assessing landslide susceptibility.

Kim, Dongyeob; Im, Sangjun; Lee, Eun Jai; Ahn, Byungkyu

2013-04-01

340

Landslide susceptibility on selected slopes in Dzanani, Limpopo Province, South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available Inherent soil properties and anthropogenic activities on slope faces are considered potential recipes for landslide occurrence. The objectives of this study were to physically characterise unconsolidated soils and identify on-going anthropogenic activities on selected slopes in Dzanani in order to appraise their role as contributory factors in enhancing landslide susceptibility. Methods employed for this study comprised mapping, description of soil profile, identification of anthropogenic activities, as well as experimental determination of soil colour, particle size distribution and Atterberg limits. Geologically, the study area comprised rocks of the Fundudzi, Sibasa and Tshifhefhe Formations, ascribed to the Soutpansberg Group. Digging of foundations for construction purposes and subsistence agriculture were identified as the main anthropogenic activities. The soils were predominantly reddish-yellow in colour, texturally variable (silty clay – clayey – silty clay loam and clay loam and of medium plasticity. Compared to soils from other parts of the world developed on volcanic cones or associated with a landslide event, those from Dzanani were qualified as generally inactive and not prone to landslides. Although the physical attributes suggested the soils were not at a critical state, on-going anthropogenic activities may enhance deep weathering and ultimately alter current soil physical characteristics to a critical state.

Makia L. Diko

2014-03-01

 
 
 
 
341

Genetics and genomics of infectious disease susceptibility.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Human genetic variation is a major determinant of susceptibility to many common infectious diseases. Malaria was the first disease to be studied extensively and many susceptibility and resistance loci have been identified. However, genes for other diseases such as HIV/AIDS and mycobacterial infections are now being identified using a variety of approaches. A large number of genes appear to influence susceptibility to infectious pathogens and defining these can provide insights into pathogenic...

Hill, Av

1999-01-01

342

Real-Time Optical Antimicrobial Susceptibility Testing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rapid antibiotic susceptibility testing is in high demand in health care fields as antimicrobial-resistant bacterial strains emerge and spread. Here, we describe an optical screening system (oCelloScope) which, based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time, introduces real-time detection of bacterial growth and antimicrobial susceptibility with imaging material to support the automatically generated graphs. Automated antibiotic susceptibility tests of a monocult...

Fredborg, Marlene; Andersen, Klaus R.; Jørgensen, Erik; Droce, Aida; Olesen, Tom; Jensen, Bent B.; Rosenvinge, Flemming S.; Sondergaard, Teis E.

2013-01-01

343

Nonequilibrium spin noise and noise of susceptibility  

Science.gov (United States)

We analyze out-of-equilibrium fluctuations in a driven spin system and relate them to the noise of spin susceptibility. In the spirit of the linear response theory we further relate the noise of susceptibility to a 4-spin correlation function in equilibrium. We show that, in contrast to the second noise (noise of noise), the noise of susceptibility is a direct measure of non-Gaussian fluctuations in the system. We develop a general framework for calculating the noise of susceptibility using the Majorana representation of spin-1/2 operators. We illustrate our approach by a simple example of noninteracting spins coupled to a dissipative (Ohmic) bath.

Schad, P.; Narozhny, B. N.; Schön, Gerd; Shnirman, A.

2014-11-01

344

Eolian additions to late Quaternary alpine soils, Indian Peaks Wilderness Area, Colorado Front Range  

Science.gov (United States)

Surface horizons of many alpine soils on Quaternary deposits in high-mountain settings are enriched in silt. The origin of these particles has been debated, particularly in the Rocky Mountain region of North America. The most common explanations are frost shattering of coarser particles and eolian additions from distant sources. We studied soil A horizons on alpine moraines of late-glacial (Satanta Peak) age in the Colorado Front Range. Surface horizons of soils on these moraines are enriched in silt and have a particle size distribution that resembles loess and dust deposits found elsewhere. The compositions of sand and silt fractions of the soils were compared to possible local source rocks, using immobile trace elements Ti, Nb, Zr, Ce, and Y. The sand fractions of soils have a wide range of trace element ratios, similar to the range of values in the local biotite gneiss bedrock. In contrast, silt fractions have narrower ranges of trace element ratios that do not overlap the range of these ratios in biotite gneiss. The particle size and geochemical results support an interpretation that silts in these soils are derived from airborne dust. Eolian silts were most likely derived from distant sources, such as the semiarid North Park and Middle Park basins to the west. We hypothesize that much of the eolian influx to soils of the Front Range occurred during an early to mid-Holocene warm period, when sediment availability in semiarid source basins was at a maximum.

Muhs, D.R.; Benedict, J.B.

2006-01-01

345

Frost ring distribution in Araucaria araucana trees from the xeric forests of Patagonia, Argentina Distribución de anillos de heladas en árboles de Araucaria araucana en bosques xéricos de la Patagonia argentina  

Directory of Open Access Journals (Sweden)

Full Text Available Frost rings are defined as anatomically abnormal and ecophysiologically pathological structures. We studied frost injuries in tree-rings of Araucaria araucana trees growing at the northern limit of its natural distribution. We recorded 121 frost injuries at two sites in the northern xeric distribution of A. Araucana forests. Frost rings at both sites were primarily restricted to the middle frost ring section of the rings. These results represent the first attempt to report and describe the occurrence of these events for this species and region. These proxy records represent important indicators of extreme temperature conditions.Las lesiones de heladas en los anillos de crecimiento de árboles son definidas como estructuras anatómicamente anómalas y ecofisiológicamente patológicas. En este trabajo se estudiaron estos anillos de heladas en árboles de Araucaria araucana creciendo al límite norte de su distribución natural. Se registraron 121 marcas de heladas para los dos sitios estudiados. En ambos sitios el mayor porcentaje de heladas se ubicaron en la mitad del anillo. Estos resultados representan un primer intento de informar y describir la ocurrencia de marcas de heladas en anillos de crecimiento para esta especie y la región. Registros de esta naturaleza representan importantes indicadores de eventos extremos en la temperatura.

Martín Ariel Hadad

2012-01-01

346

Frost ring distribution in Araucaria araucana trees from the xeric forests of Patagonia, Argentina / Distribución de anillos de heladas en árboles de Araucaria araucana en bosques xéricos de la Patagonia argentina  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Las lesiones de heladas en los anillos de crecimiento de árboles son definidas como estructuras anatómicamente anómalas y ecofisiológicamente patológicas. En este trabajo se estudiaron estos anillos de heladas en árboles de Araucaria araucana creciendo al límite norte de su distribución natural. Se [...] registraron 121 marcas de heladas para los dos sitios estudiados. En ambos sitios el mayor porcentaje de heladas se ubicaron en la mitad del anillo. Estos resultados representan un primer intento de informar y describir la ocurrencia de marcas de heladas en anillos de crecimiento para esta especie y la región. Registros de esta naturaleza representan importantes indicadores de eventos extremos en la temperatura. Abstract in english Frost rings are defined as anatomically abnormal and ecophysiologically pathological structures. We studied frost injuries in tree-rings of Araucaria araucana trees growing at the northern limit of its natural distribution. We recorded 121 frost injuries at two sites in the northern xeric distributi [...] on of A. Araucana forests. Frost rings at both sites were primarily restricted to the middle frost ring section of the rings. These results represent the first attempt to report and describe the occurrence of these events for this species and region. These proxy records represent important indicators of extreme temperature conditions.

Martín Ariel, Hadad; Mariano Martín, Amoroso; Fidel Alejandro, Roig Juñent.

347

Viscoelastic ferrogel: dynamic magnetic susceptibilities  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Theoretical model to describe magnetodynamics of a ferrogel, i.e., an assembly of ferromagnetic nanoparticles embedded in a gel, is proposed. The reorientations of the particles are determined by the influence of the elastic matrix and the rotational Brownian motion. The set of essential parameters, [...] on which the components of the dynamic magnetic susceptibility tensor depend, is discussed. In the framework of the model, absorption of the energy of an ac field is studied. With allowance for the interaction of elastic and Brownian forces, the effective relaxation times and eigenfrequencies for the longitudinal and transverse components of the ferrogel magnetization are evaluated.

Yu. L., Raikher; V. V., Rusakov.

2001-09-01

348

Plant survival of barbados cherry genotypes after frost injury in northern Parana State/ Recuperação de plantas de genótipos de aceroleira afetadas por geada no norte do Paraná  

Directory of Open Access Journals (Sweden)

Full Text Available Barbados cherry is a tropical fruit that when cultivated in subtropical areas is exposed to frosts which cause considerable damages to the leaves and can kill plants. The frosts of July 2000 in Northern Paraná State made possible the evaluation of 19 Barbados cherry genotypes propagated through cuttings. A minimum air temperature of –1,3°C was recorded on 17 July at the meteorological station; the minimum ground temperature was around –5,4°C. All plants were severely injured in 100% of leaves. The evaluation was made the following year to the frost, through sprouts status. It was observed that Barbados cherry genotypes present differences in cold hardiness. Some genotypes were killed and others survived, with good vegetation on the next year. The following genotypes presented the best recovery: ‘Cícero’, ‘Roseli’, ‘Carolina’ and ‘Lígia.’ The findings are discussed in relation to temperature limits reported in the literature.A aceroleira é uma planta de clima tropical que também tem sido cultivada em áreas subtropicais, ficando com isso sujeita à ocorrência de geadas, que causam danos consideráveis à folhagem e podem levar as plantas à morte. As geadas de julho de 2000 no Norte do Paraná possibilitaram a avaliação de 19 genótipos de acerola, propagados vegetativamente. A temperatura mínima foi de –1,3° C no abrigo meteorológico em 17 de julho, que corresponde a – 5,4 °C na relva. Todas as plantas tiveram danos em 100% das folhas. No ano seguinte à geada, avaliou-se a recuperação das plantas com base na brotação apresentada. Com os resultados obtidos, conclui-se que os genótipos de aceroleira apresentam respostas diferentes à geada, sendo que alguns são levados à morte e outros conseguem se recuperar na estação de crescimento seguinte. Os genótipos que apresentaram melhor recuperação foram: ‘Cícero’, ‘Roseli’, ‘Carolina’ e ‘Lígia’. Os resultados são discutidos em relação às temperaturas-limite relatadas na literatura.

Inês Cristina de Batista Fonseca

2002-05-01

349

Effect of extra-fine slag replacement on carbonation and frost salt scaling resistance of mortars[ACI SP-234-8  

Energy Technology Data Exchange (ETDEWEB)

This study examined the effects of extra-fine slag (EFS) on the carbonation and frost salt scaling resistance of mortars at different replacement levels for 2 types of cements. In the first part of the examination, EFS replaced a certain amount of European CEM 3/B cement composed of 67 per cent slag with ordinary fineness. The second part examined the effect of EFS on microstructure and frost salt scaling resistance of mortars at different replacement levels in European normal portland cement CEM 1 32,5R. The average Blaine fineness of EFS was 500 m{sup 2}/kg. The water to cement ratio was maintained at 0.45. The carbonation resistance and pore structure of the cement mortars was examined. Carbonation resistance was measured using the phenolphthalein method after accelerated carbonation tests in a 3 per cent carbon dioxide chamber. Mercury intrusion porosimetry was used to study the pore structures. The chemical and physical properties of this cement were presented along with the obtained cement blends. The first part of the study showed that increasing the average fineness and total amount of slag results in a higher degrees of water uptake compared to the control sample. Therefore, it was claimed that the critical amount of normal portland cement clinker is important in terms of carbonation and frost salt scaling durability. It was concluded that an increasing EFS content lowers the scaling resistance. The effect is most evident when the replacement percentage is increased from 50 to 75 per cent. It was suggested that future studies should focus on the content of normal portland cement clinker, the hydration rate of clinker and slag, as well as the related activation of the slag. 10 refs., 5 tabs., 12 figs.

Copuroglu, O.; Fraaij, A.; Schlangen, E. [Delft Univ. of Technology, Delft (Netherlands). Dept. of Civil Engineering; Bijen, J. [INTRON (Netherlands)

2006-07-01

350

Linking soil biodiversity and agricultural soil management  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Soil biodiversity vastly exceeds aboveground biodiversity, and is prerequisite for ecosystem stability and services. This review presents recent findings in soil biodiversity research focused on interrelations with agricultural soil management. Richness and community structure of soil biota depend on plant biodiversity and vice versa. Soil biota govern nutrient cycling and storage, soil organic matter (SOM) formation and turnover. Agriculture manipulates plants, soils and SOM. With intensific...

Thiele-bruhn, S.; Bloem, J.; Vries, F. T.; Kalbitz, K.; Wagg, C.

2012-01-01

351

LOREF: Air cooler optimisation with reduction of ice and frost formation - Optimisation of lamella air-coolers/evaporators of air/water heat pumps - Part 2: mathematical-physical simulation of the lamella air-coolers with condensate and frost formation; LOREF: Luftkuehler-Optimierung mit Reduktion von Eis- und Frostbildung - Optimierung des Lamellenluftkuehlers/Verdampfers von Luft/Wasser-Waermepumpen - Teil 2: mathematisch-physikalische Simulation des Lamellenluftkuehlers mit Kondensat- und Frostbildung  

Energy Technology Data Exchange (ETDEWEB)

The average coefficient of performance (COP) of air/water heat pumps shall be further improved over the next decade. Its success will strongly depend on two measures: by altering the characteristic of the heat pump through continuous operation instead of on/off operation, and further, by reducing the formation of frost and ice. Frost significantly reduces the air flow, and consequently also the heat and mass transfer in the fin tube evaporator. The formation of frost and ice is influenced by a complex interaction between the fin tube evaporator, the characteristic of the fan and of the heat pump itself. An accurate prediction of these processes is required to optimize the design of the fin tube evaporator in combination with fan and heat pump to further improve the overall efficiency. Based on the theory of simultaneous heat and mass transfer combined with partial condensation and desublimation, a simulation program for the prediction of frost and ice formation has been developed, being valid over the wide range of the ambient air (from -10 {sup o}C to 15 {sup o}C and dry to saturated air). The humidity is deposited either as condensate, frost, ice or as a combination of them on the fins and tubes of the evaporator. It was a major challenge to create a correlation for the physical properties of the frost and ice layer in the unsteady processes. By numerous experiments, four regions of physical properties are distinguished, depending on the temperature at the boundary layer between air and frost or ice: condensate above -2.7 {sup o}C, condensate and ice between -3.5 {sup o}C to -2.7 {sup o}C, ice and frost between -5.2 {sup o}C to -3.5 {sup o}C and frost formed directly by desublimation below -5.2 {sup o}C. A high reliability has been obtained with the mathematical-physical simulation program proven over the entire applicable range of air temperature and humidity, temperature difference for heat transfer, air velocity and geometry of the fin tube evaporator. (author)

Sahinagic, R.; Gasser, L.; Wellig, B.; Hilfiker, K.

2008-04-15

352

Efeitos de geadas em mudas de espécies arbóreas de mata ciliar utilizadas em ensaios de campo / Frost effect on galery forest arboreal species seedings used in field test  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Indivíduos de espécies arbóreas ocorrentes em matas ripárias, plantadas com idades entre 1 e 2 anos, foram investigadas quanto à sensibilidade a geadas a partir de junho/agosto de 1990, quando estas ocorreram no município de Moji-Guaçu, SP. Dessas, pelo menos duas atingiram as mudas na área experime [...] ntal. Cerca de 2.750 indivíduos de 13 espécies, plantados numa área de 2,5 ha, situada à margem direita do rio Moji-Guaçu, foram avaliados mensalmente quanto à variação de altura total e dos seus rebrotes. Atribuíram-se notas de 1 a 5, conforme critérios pré-estabelecidos e observaram-se: aspectos da morfologia geral; início do brotamento das gemas vegetativas e o comportamento dos indivíduos de acordo com a proximidade do rio. Os efeitos mais evidentes nas plantas foram: modificação da cor e textura das folhas, que ficaram enegrecidas ou avermelhadas, seguida de abscisão e morte total ou parcial da parte aérea. Os resultados indicam que das espécies estudadas, apenas Platycyamus regnelli Benth. (Leguminosae), Hymenaea courbaril L. (Leguminosae) e Alchornea sp. (Euphorbiaceae), apresentaram restrições quanto ao plantio por mudas, em regiões sujeitas à geadas periódicas. As demais espécies demonstraram grande capacidade de recuperação, sugerindo resistência e/ou tolerância, quando sob açáo de geadas. Abstract in english One to two-year-old seedlings of tree species found in riparian forests were investigated for frost sensibility as of June/August 1990, in Moji-Guaçu Municipality. São Paulo State. At least two frost affected the seedlings in the experimental area during this period. Around 2750 seedlings from 13 sp [...] ecies were planted in a 2.5-hectare area on the shores of the Moji-Guaçu river. Variations in total height and budding were recorded monthly. Scores from to 5 were given based on pre-stablished criteria. General morphology, initiation of vegetative growth and seedling behavior were observed in relation to riverbank proximity. The most obvious effects on seedlings were changes in leaf color and texture; the leaves turned blackish or reddish, followed by abscission and total or partial death of aerial parts. Of the species investigated, planting restrictions on seedlings in frost-prone areas should be applied only to Platycyamus regnelli Benth. (Leguminosae), Hymenaea courbaril L. (Leguminosae) and Alchornea s (Euphorbiaceae). The other species showed considerable capacity for recuperation, suggesting resistance and/or tolerance to frost damage.

Luiz Mauro, Barbosa; José Marcos, Barbosa; Cristina, Bedinelli; Lilian Maria, Asperti; Evelyn de Freitas, Belasque; Eduardo Amaral, Batista.

1993-07-01

353

Helium Exhaust Studies in H-Mode Discharges in the DIII-D Tokamak Using an Argon-Frosted Divertor Cryopump  

International Nuclear Information System (INIS)

The first experiments demonstrating exhaust of thermal helium in a diverted, H-mode deuterium plasma have been performed on the DIII-D tokamak. The helium, introduced via gas puffing, is observed to reach the plasma core, and then is readily removed from the plasma with a time constant of ?10--20 energy-confinement times by an in-vessel cryopump conditioned with argon frosting. Detailed analysis of the helium profile evolution suggests that the exhaust rate is limited by the exhaust efficiency of the pump (?5%) and not by the intrinsic helium-transport properties of the plasma

354

Impact of broom, Cytisus scoparius (Fabaceae), in naturally treeless sub-alpine frost-hollow vegetation communities at the Barrington Tops, south-eastern Australia  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The exotic shrub Cytisus scoparius (L.) Link (family Fabaceae), known as broom, is having a major impact on native vegetation in naturally treeless sub-alpine frost-hollow areas (c. 32o 01’ 37” S, 151o 26’ 12” E’, 1440 m elevation) at the Barrington Tops, New South Wales, in south-eastern Australia. This vegetation is of limited extent and has significant biogeographical and ecological importance. Nine paired 10 m line transects were compared, with one of the pair in areas of almost...

Hosking, John R.; Schroder, Mellesa; Mccorkell, Bruce

2013-01-01

355

Resistência de espécies arbóreas submetidas a extremos climáticos de geada em diferentes sistemas agroflorestais / Resistance of arboreal species submitted to extreme frost in different agroforestry systems  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O presente trabalho teve como objetivo avaliar a resposta das espécies arbóreas Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafístula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) e o híbrido Eucalyptus uroph [...] ylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) em consórcio com a cana-de-açúcar (Saccharum spp.) em dois arranjos de sistemas agroflorestais (faixa - 3x3m + 12m e linha - 6x1,5m) submetidos a extremos climáticos de geada, na região Noroeste do Rio Grande do Sul. Os danos (resistência á geada) foram avaliados segundo o sistema de notas utilizado por HIGA et al. (2000) no qual atribuiu-se uma nota de 0 a 10 conforme a intensidade do dano na planta. Para os graus de resistência à geada, adaptou-se metodologia utilizada por CARVALHO (1981), a qual também é em função da intensidade do dano na planta. Diante da condição de geada estudada, observa-se que os diferentes arranjos de sistemas agroflorestais afetam a resistência da espécie guapuruvu, sendo sensível no sistema agroflorestal faixa e moderadamente tolerante no sistema linha. Em ambos os sistemas, as espécies angico-vermelho, bracatinga e eucalipto mostram-se resistentes, enquanto que a canafístula demonstra ser tolerante. Abstract in english The present research had the aim to evaluate the answers of the arboreal species Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafístula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) and the hybrid Eucalyptus u [...] rophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) in consortium with sugar cane (Saccharum spp.) in two agroforestry arrangement systems (strip - 3x3m + 12m and line - 6x1,5m) submitted to climatic extreme frost conditions, in the Northwest of Rio Grande do Sul. The damages (resistance to frost) were appraised according to the system of notes used by HIGA et al. (2000) in which a note from 0 to 10 was attributed according to the intensity of the damage to the plant. For the resistance degrees to frost, it was adapted the methodology used by CARVALHO (1981), which is also in function of the intensity of the damage to the plant. Upon the frost condition studied, it was observed that the results demonstrated that different of agroforest system arrangements damaged the resistance of the guapuruvu specie, being sensitive in the agroforest system strip and moderatelly tolerant in the system line. In both systems, the species angico-vermelho, bracatinga e eucalipto showed resistance, while the canafístula demonstrated to be tolerant.

Velci Queiróz de, Souza; Braulio Otomar, Caron; Denise, Schmidt; Alexandre, Behling; Rogério, Bamberg; Andre Luis, Vian.

2011-06-01

356

?-Lactamase Genes of the Penicillin-Susceptible Bacillus anthracis Sterne Strain  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Susceptibility to penicillin and other ?-lactam-containing compounds is a common trait of Bacillus anthracis. ?-lactam agents, particularly penicillin, have been used worldwide to treat anthrax in humans. Nonetheless, surveys of clinical and soil-derived strains reveal penicillin G resistance in 2 to 16% of isolates tested. Bacterial resistance to ?-lactam agents is often mediated by production of one or more types of ?-lactamases that hydrolyze the ?-lactam ring, inactivating the antimi...

Chen, Yahua; Succi, Janice; Tenover, Fred C.; Koehler, Theresa M.

2003-01-01

357

Magnetic properties of alluvial soils polluted with heavy metals  

Science.gov (United States)

Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (P?íbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on magnetic extracts indicated the presence of magnetite/maghemite in the uppermost layers, and strong mineralogical transformation of iron oxyhydroxides during heating. Magnetic techniques give valuable information about the soil Fe oxides, which are useful for investigation of the environmental effects in soil. Key words: magnetic methods, Fe oxides, pollution, alluvial soils.

Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

2012-04-01

358

Antibiotic Susceptibilities of Parachlamydia acanthamoeba in Amoebae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Parachlamydia acanthamoeba are intracellular bacteria of amoebae and are considered potential etiological agents of human pneumonia. We have determined the in vitro antibiotic susceptibilities of two strains (strain Bn9 and Hall's coccus) in Acanthamoeba polyphaga. The two strains were susceptible to tetracyclines, macrolides, and rifampin, but resistant to fluoroquinolones.

Maurin, M.; Bryskier, A.; Raoult, D.

2002-01-01

359

Resistance of soil microorganisms to starvation.  

Science.gov (United States)

Most groups of soil microorganisms died when exposed to prolonged starvation in a carbon-free solution, but the relative abundance of Bacillus and actinomycetes increased with time. Certain nonspore-forming bacteria also persisted. The ability of individual soil isolates to endure starvation in solution was not correlated with their glycogen content or rate of endogenous respiration. However, cells of the resistant populations were rich in poly-beta-hydroxybutyrate, whereas the starvation-susceptible bacteria generally contained little of this substance. Poly-beta-hydroxybutyrate was used rapidly in cells deprived of exogenous sources of carbon.

Chen, M.; Alexander, M.

1972-01-01

360

Chiral susceptibility and the scalar Ward identity  

International Nuclear Information System (INIS)

The chiral susceptibility is given by the scalar vacuum polarization at zero total momentum. This follows directly from the expression for the vacuum quark condensate so long as a nonperturbative symmetry preserving truncation scheme is employed. For QCD in-vacuum the susceptibility can rigorously be defined via a Pauli-Villars regularization procedure. Owing to the scalar Ward identity, irrespective of the form or Ansatz for the kernel of the gap equation, the consistent scalar vertex at zero total momentum can automatically be obtained and hence the consistent susceptibility. This enables calculation of the chiral susceptibility for markedly different vertex Ansaetze. For the two cases considered, the results were consistent and the minor quantitative differences easily understood. The susceptibility can be used to demarcate the domain of coupling strength within a theory upon which chiral symmetry is dynamically broken. Degenerate massless scalar and pseudoscalar bound-states appear at the critical coupling for dynamical chiral symmetry breaking

 
 
 
 
361

Evolution and significance of soil magnetism of basalt-derived chronosequence soils in tropical southern China  

Directory of Open Access Journals (Sweden)

Full Text Available Soil samples were collected from eight basalt- derived chronosequence soils with the ages of 0.01, 0.58, 0.92, 1.33, 2.04, 3.04, 3.76 and 6.12 Ma respectively from Leizhou Peninsula and northern Hainan Island of tropical southern China. Magnetic parameters of magnetic susceptibility (MS, percentage of frequency-dependent magnetic susceptibility (FDS%, anhysteretic remanent magnetization (ARM, saturation isothermal remanent magnetization (SIRM, soft and hard isothermal remanent magnetization (IRMs and IRMh of the collected samples were measured to study the evolution and the significance of the magnetism with soil age. The results show that the magnetic parameters changed fast from Primosols to Ferrosols (0.01 ~ 0.92 Ma but slowly at Ferralosols stage (1.33 Ma~, it suggests a stable phase occurred for soil magnetism at Ferralosols, the existence of this phase could be supported by the little changes in the contents of clay, Fet and Fed. Obvious differences existed in the values of magnetic parameters between Ferralosols and other soil types (Primosols and Ferrosols, FDS%: Ferralosols > 10%, Primosols and Ferrosols < 10%; ARM, Ferralosols < 7000 × 10–8· SIm3·kg–1, Primosols and Ferrosols > 8000 × 10–8 SIm3·kg–1, thus, it is possible to differentiate Ferralosols from other soil types in tropical region by using magnetic indices.

Decheng Li

2011-11-01

362

Application of likelihood ratio and logistic regression models to landslide susceptibility mapping using GIS.  

Science.gov (United States)

For landslide susceptibility mapping, this study applied and verified a Bayesian probability model, a likelihood ratio and statistical model, and logistic regression to Janghung, Korea, using a Geographic Information System (GIS). Landslide locations were identified in the study area from interpretation of IRS satellite imagery and field surveys; and a spatial database was constructed from topographic maps, soil type, forest cover, geology and land cover. The factors that influence landslide occurrence, such as slope gradient, slope aspect, and curvature of topography, were calculated from the topographic database. Soil texture, material, drainage, and effective depth were extracted from the soil database, while forest type, diameter, and density were extracted from the forest database. Land cover was classified from Landsat TM satellite imagery using unsupervised classification. The likelihood ratio and logistic regression coefficient were overlaid to determine each factor's rating for landslide susceptibility mapping. Then the landslide susceptibility map was verified and compared with known landslide locations. The logistic regression model had higher prediction accuracy than the likelihood ratio model. The method can be used to reduce hazards associated with landslides and to land cover planning. PMID:15559946

Lee, Saro

2004-08-01

363

SOIL STRUCTURAL DEGRADATION RISK IN HOROIATA BASIN (TUTOVA HILLS  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study is to investigate a component of the physical soil quality, this being the structural degradation risk. The study area has been the basin of Horoiata River. The profile database used in the study consists of over 140 profile samples, dispersed all over the basin. The indexes used have been soil crusting index, the compaction degree and the susceptibility to cracking

Ionu? Vasiliniuc

2009-10-01

364

Fabrication and anti-frosting performance of super hydrophobic coating based on modified nano-sized calcium carbonate and ordinary polyacrylate  

Energy Technology Data Exchange (ETDEWEB)

Nano-sized calcium carbonate (CaCO{sub 3}) particles were modified by heptadecafluorodecyl trimethoxysilane under acidic water condition. An ordinary polyacrylate prepared via radical copolymerization of methyl methacrylate, butyl acrylate, acrylic acid and {beta}-hydroxyethyl methacrylate was used as the binder to form hydrophobic coatings with the modified CaCO{sub 3}. Super hydrophobic coating with water contact angle of 155{sup o} was obtained from modified CaCO{sub 3} and the polyacrylate at their weight ratio of 8/2 by a simple procedure. Based on surface analysis by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the super hydrophobicity can be attributed to both the surface microstructure and surface enrichment of fluoroalkyl chains. Due to a low water sliding angle, carbon black powder on super hydrophobic surface was easily removed by rolling water droplet. Furthermore, the anti-frosting performance of different surfaces was investigated, which indicated that the frost formed on superhydrophobic surface was greatly retarded compared with that on bare copper surface. The surface kept super hydrophobicity even after freezing-thawing treatment for 10 times.

Wang Hao [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Tang Liming [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: tanglm@mail.tsinghua.edu.cn; Wu Xiaomin; Dai Wantian [Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Qiu Yipeng [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2007-09-15

365

Fabrication and anti-frosting performance of super hydrophobic coating based on modified nano-sized calcium carbonate and ordinary polyacrylate  

Science.gov (United States)

Nano-sized calcium carbonate (CaCO 3) particles were modified by heptadecafluorodecyl trimethoxysilane under acidic water condition. An ordinary polyacrylate prepared via radical copolymerization of methyl methacrylate, butyl acrylate, acrylic acid and ?-hydroxyethyl methacrylate was used as the binder to form hydrophobic coatings with the modified CaCO 3. Super hydrophobic coating with water contact angle of 155° was obtained from modified CaCO 3 and the polyacrylate at their weight ratio of 8/2 by a simple procedure. Based on surface analysis by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), the super hydrophobicity can be attributed to both the surface microstructure and surface enrichment of fluoroalkyl chains. Due to a low water sliding angle, carbon black powder on super hydrophobic surface was easily removed by rolling water droplet. Furthermore, the anti-frosting performance of different surfaces was investigated, which indicated that the frost formed on superhydrophobic surface was greatly retarded compared with that on bare copper surface. The surface kept super hydrophobicity even after freezing-thawing treatment for 10 times.

Wang, Hao; Tang, Liming; Wu, Xiaomin; Dai, Wantian; Qiu, Yipeng

2007-09-01

366

Elevated CO{sub 2} and development of frost hardiness in Norway spruce (picea abies (L.) Karst.); Oekt CO{sub 2} og utvikling av frostherdighet i gran  

Energy Technology Data Exchange (ETDEWEB)

This thesis discusses controlled laboratory experiments carried out to study the effects of CO{sub 2} pollution on Norwegian spruce. It was found that elevated CO{sub 2} increased height growth and biomass production. It slightly increased frost hardiness, but only at high nitrogen values. There was no evidence of adverse effects of elevated CO{sub 2} on the phenology of bud set and the development of frost hardiness. Although not statistically significant, there seemed to be a consistently higher concentration of soluble carbohydrates in one-season-old Norway spruce seedlings treated with elevated CO{sub 2}. This was not found in three-year-old seedlings grown in open top chambers, possibly indicating a down-regulation of photosynthesis or a transition from free to predetermined growth, and change in allocation of photosynthates with age. Treatment with high or low concentrations of CO{sub 2} and nitrogen fertilizer did not affect apoplastic chitinolytic activity during cold acclimation, nor were there any effects on antifreeze activity in these apoplastic extracts from cold acclimated needles. 149 refs., 21 figs., 8 tabs.

Dalen, Lars Sandved

1998-09-01

367

Effect of Ice and Frost Formations on Drag of NACA 65(sub 1) -212 Airfoil for Various Modes of Thermal Ice Protection  

Science.gov (United States)

The effects of primary and. runback icing and frost formations on the drag of an 8-foot-chord NACA 651-212 airfoil section were investigated over a range of angles of attack from 20 to 80 and airspeeds up to 260 miles per hour for icing conditions with liquid-water contents ranging from 0.25 to 1.4 grams per cubic meter and datum air temperatures of -30 to 30 F. The results showed that glaze-ice formations, either primary or runback, on the u