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Sample records for frost susceptible soil

  1. Frost Susceptibility of Soil, Review of Index Tests,

    1981-12-01

    Schaible (1957) 36 36. Frost susceptibility criteria according to Floss 37 37 Ruhr University at Bo(hum frost susceptibility criteria according to I...freezing front causes ening can take place. alternating bands of soil and ice to form. The ex- It is important, then, that both kinds of frost ternal...particles and the uniformity early research concentrated on a narrow band of of the gradation of soil particle sizes less than heat extraction rates

  2. Susceptibility to Frost-Bite

    Bal Krishna

    1966-11-01

    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.

  3. Frost susceptibility of granular subbase materials contaminated by deicing chemicals

    Jørgensen, Anders Stuhr; Orlander, Tobias; Doré, Guy

    2013-01-01

    to be caused by ice segregation, but rather a volume increase by fusion caused by a small amount of pore water. The direction of the frost front could not be determined from the collected test results, and no reduction in bearing capacity or increase in frost susceptibility can be derived from the collected...... on roads and airfields enter the granular subbase materials and thereby makes the soil more frost-susceptible. In this project a series of isothermal frost heave tests has been carried out on granular subbase material from the runway at Kuujjuaq Airport, Québec, Canada. The tests have been carried out......, were used in order to determine any influence from the cooling ramp. The tests included settings that allowed the samples additional brine during freezing. Hence, the water and salinity were measured before and after the tests in order to determine the redistribution of water and salinity. The test...

  4. Frost Heave in Colloidal Soils

    Peppin, Stephen

    2011-01-01

    We develop a mathematical model of frost heave in colloidal soils. The theory accountsfor heave and consolidation while not requiring a frozen fringe assumption. Two solidificationregimes occur: a compaction regime in which the soil consolidates to accommodate the ice lenses, and a heave regime during which liquid is sucked into the consolidated soil from an external reservoir, and the added volume causes the soil to heave. The ice fraction is found to vary inversely with thefreezing velocity V , while the rate of heave is independent of V , consistent with field and laboratoryobservations. © 2011 Society for Industrial and Applied Mathematics.

  5. Influence of fines content on the anti-frost properties of coarse-grained soil

    TianLiang Wang; ZuRun Yue; TieCheng Sun; JinChuang Hua

    2015-01-01

    This paper aims to determine the optimal fines content of coarse-grained soil required to simultaneously achieve weaker frost susceptibility and better bearing capacity. We studied the frost susceptibility and strength properties of coarse-grained soil by means of frost heaving tests and static triaxial tests, and the results are as follows: (1) the freezing temperature of coarse-grained soil decreased gradually and then leveled off with incremental increases in the percent content of fines; (2) the fines content proved to be an important factor influencing the frost heave susceptibility and strength properties of coarse-grained soil. With incremental increases in the percent content of fines, the frost heave ratio increased gradually and the cohesion function of fines effectively enhanced the shear strength of coarse-grained soil before freeze-thaw, but the frost susceptibility of fines weakened the shear strength of coarse-grained soil after freeze-thaw; (3) with increasing numbers of freeze-thaw cycles, the shear strength of coarse-grained soil decreased and then stabilized after the ninth freeze-thaw cycle, and therefore the mechanical indexes of the ninth freeze-thaw cycle are recommended for the engi-neering design values; and (4) considering frost susceptibility and strength properties as a whole, the optimal fines content of 5% is recommended for railway subgrade coarse-grained soil fillings in frozen regions.

  6. Hydrological significance of soil frost for pre-alpine areas

    Stähli, Manfred

    2017-03-01

    Soil frost can have a substantial impact on water flows at the soil surface and-potentially-alter the dynamics of catchment runoff. While these findings are mainly based on studies from alpine and Northern-latitude areas (including permafrost areas), little is known about the significance of soil frost for hydrology in pre-alpine areas, i.e. the region at the transition from central European lowlands to high-alpine areas. Here I synthesize soil temperature data and soil frost observations from ten sites in Switzerland to assess the occurrence of soil frost and to determine its impact on catchment runoff. In addition, a well-established numerical model was used to reconstruct the presence of soil frost in two first-order catchments for single runoff events and winters. The data clearly demonstrates that shallow soil frost has formed regularly in this altitudinal range over the past decade. The presence of a frozen soil surface was found to be highly variable among the sites under study and did not significantly correlate with altitude or forest density. For the first-order catchments, it was not possible to relate important flood peaks or increased runoff coefficients to winter situations with substantial soil frost. Thus, the present analysis suggests that although soil frost is widespread and regularly occurring at this altitudinal range, it has no significant impact on winter runoff in pre-alpine watersheds.

  7. Frost susceptibility of sub-base gravel used in Pearl-Chain Bridges: an experimental investigation

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Andersen, Iben Brøndum

    2016-01-01

    This study investigates frost susceptibility of sub-base gravel determined by the ASTM D5918-13 standard as a conservative estimate of the frost heave risk of fill in overfilled arch bridges, particularly in Pearl-Chain Bridges. Frost heave of granular materials has been of great research interest...

  8. Optimum soil frost depth to alleviate climate change effects in cold region agriculture

    Yanai, Yosuke; Iwata, Yukiyoshi; Hirota, Tomoyoshi

    2017-03-01

    On-farm soil frost control has been used for the management of volunteer potatoes (Solanum tuberosum L.), a serious weed problem caused by climate change, in northern Japan. Deep soil frost penetration is necessary for the effective eradication of unharvested small potato tubers; however, this process can delay soil thaw and increase soil wetting in spring, thereby delaying agricultural activity initiation and increasing nitrous oxide emissions from soil. Conversely, shallow soil frost development helps over-wintering of unharvested potato tubers and nitrate leaching from surface soil owing to the periodic infiltration of snowmelt water. In this study, we synthesised on-farm snow cover manipulation experiments to determine the optimum soil frost depth that can eradicate unharvested potato tubers without affecting agricultural activity initiation while minimising N pollution from agricultural soil. The optimum soil frost depth was estimated to be 0.28–0.33 m on the basis of the annual maximum soil frost depth. Soil frost control is a promising practice to alleviate climate change effects on agriculture in cold regions, which was initiated by local farmers and further promoted by national and local research institutes.

  9. Prediction of soil frost penetration depth in northwest of Iran using air freezing indices

    Mohammadi, H.; Moghbel, M.; Ranjbar, F.

    2016-11-01

    Information about soil frost penetration depth can be effective in finding appropriate solutions to reduce the agricultural crop damage, transportations, and building facilities. Amongst proper methods to achieve this information are the statistical and empirical models capable of estimating soil frost penetration depth. Therefore, the main objective of this research is to calculate soil frost penetration depth in northwest of Iran during the year 2007-2008 to validate two different models accuracy. To do so, the relationship between air and soil temperature in different depths (5-10-20-30-50-100 cm) at three times of the day (3, 9, and 15 GMT) for 14 weather stations over 7 provinces was analyzed using linear regression. Then, two different air freezing indices (AFIs) including Norwegian and Finn AFI was implemented. Finally, the frost penetration depth was calculated by McKeown method and the accuracy of models determined by actual soil frost penetration depth. The results demonstrated that there is a significant correlation between air and soil depth temperature in all studied stations up to the 30 cm under the surface. Also, according to the results, Norwegian index can be effectively used for determination of soil frost depth penetration and the correlation coefficient between actual and estimated soil frost penetration depth is r = 0.92 while the Finn index overestimates the frost depth in all stations with correlation coefficient r = 0.70.

  10. Influence of soil frost on the character and degradability of dissolved organic carbon in boreal forest soils

    Panneer Selvam, B.; Laudon, H.; Guillemette, F.; Berggren, M.

    2016-03-01

    Recent studies suggest that increases in extent and duration of winter soil frost increases dissolved organic carbon (DOC) concentrations in boreal riparian soils and connected aquatic systems during the subsequent spring and summer. However, little is known about the impact of frost on DOC character and its degradability. We applied three experimental treatments to riparian soils in northern Sweden—shallow soil frost (insulated), deep soil frost (snow removed) and control plots—to test the effect of different soil frost regimes on the chemical characteristics and degradability of soil DOC. Soil pore water samples were analyzed using excitation-emission fluorescence (parallel factor analysis) combined with biological and photochemical degradation experiments. We found that the absolute bacterial metabolic rates were significantly lower in samples from the shallow soil frost treatments, compared with the other treatments. Explorative multivariate analyses indicate that increasing soil frost is contributing to increased protein-like fluorescence and to increased biological degradability of the DOC. Our study shows that decreases in riparian soil frost due to climate warming may not only contribute to decreased riparian DOC concentrations but also lead to shifts in the DOC composition, resulting in decreased biodegradability (yet similar photodegradability) of the DOC that is exported from riparian soils to streams.

  11. Significance of frost action and surface soil characteristics to wind erosion at Rocky Flats, Colorado. Second progress report, October 1, 1975--May 30, 1976

    Caine, N.; Morin, P.

    1976-01-01

    This report summarizes information on soil frost effects collected on Rocky Flats during the 1975-1976 winter. On a broad scale, work on soil textures at and just below the ground surface corroborates the conclusion reached earlier that the general frost susceptibility of the Rocky Flats soils is quite well keyed to topography. This is incorporated into a mapping procedure for potential soil frost activity which is applied to the northwestern part of the Rocky Flats area. On a site scale, instrumental records of weather conditions and soil responses have been maintained from October, 1975, to May, 1976, at the Lindsay Ranch study site, northwest of the Rocky Flats Plant. During that period, 33 needle ice events have been observed and recorded and are described in this report. A preliminary examination of wind data for the same period suggests that the soil in areas of natural vegetation on the site are not exposed to wind action. If, however, they were exposed, winds capable of eroding them are common.

  12. Enhanced winter soil frost reduces methane emission during the subsequent growing season in a boreal peatland.

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2016-02-01

    Winter climate change may result in reduced snow cover and could, consequently, alter the soil frost regime and biogeochemical processes underlying the exchange of methane (CH4 ) in boreal peatlands. In this study, we investigated the short-term (1-3 years) vs. long-term (11 years) effects of intensified winter soil frost (induced by experimental snow exclusion) on CH4 exchange during the following growing season in a boreal peatland. In the first 3 years (2004-2006), lower CH4 emissions in the treatment plots relative to the control coincided with delayed soil temperature increase in the treatment plots at the beginning of the growing season (May). After 11 treatment years (in 2014), CH4 emissions were lower in the treatment plots relative to the control over the entire growing season, resulting in a reduction in total growing season CH4 emission by 27%. From May to July 2014, reduced sedge leaf area coincided with lower CH4 emissions in the treatment plots compared to the control. From July to August, lower dissolved organic carbon concentrations in the pore water of the treatment plots explained 72% of the differences in CH4 emission between control and treatment. In addition, greater Sphagnum moss growth in the treatment plots resulted in a larger distance between the moss surface and the water table (i.e., increasing the oxic layer) which may have enhanced the CH4 oxidation potential in the treatment plots relative to the control in 2014. The differences in vegetation might also explain the lower temperature sensitivity of CH4 emission observed in the treatment plots relative to the control. Overall, this study suggests that greater soil frost, associated with future winter climate change, might substantially reduce the growing season CH4 emission in boreal peatlands through altering vegetation dynamics and subsequently causing vegetation-mediated effects on CH4 exchange.

  13. Magnetic susceptibility properties of polluted soils

    2000-01-01

    An investigation of magnetic properties using magnetic susceptibility (X) and frequency-dependent susceptibility (Xfd) was conducted on representative modern pollutants, which include smelted slag dust, automobile exhaust dust and coal ash. Their magnetic susceptibility values are more than 500×10-8 m3/kg, and frequency-dependent susceptibility values less than 3%, indicating that ample ferrimagnetic and scanty superparamagnetic grains occurred in the studied pollutants. Similar to the artificially synthetic polluted soils, the industrially-polluted soils display a negative relationship between magnetic susceptibility and frequency-dependent susceptibility. However, the unpolluted soils, e.g. the Quaternary loess in the Chinese Loess Plateau, show a positive relationship between them. In this note, we propose a convenient and effective approach for identifying the polluted soils.

  14. Significance of frost action and surface soil characteristics to wind erosion at Rocky Flats, Colorado. Final report

    Caine, N.

    1978-09-01

    This study of the potential links between soil freezing and wind erosion was conducted at Rocky Flats during 4 winters. Most of the study has involved the conditions leading to the growth of segregation ice in the surface soil and the ground heave which that produces. This occurs about 15 times in the average winter at Rocky Flats, always on a diurnal cycle. Such frost action is preferentially distributed in time and space and cannot be estimated from air temperatures alone. November and March are the months of most frequent frost heave, and then only in the days following precipitation or snowmelt. The most marked frost effects are found on exposed interfluve and hillcrest situations, where there are patches of bare soil. Almost no effects are found on the valley floors. Soil disturbance by segregation ice leads to a marked decrease in soil bulk density, and presumably in soil strength though this change has not been quantitatively defined. However, this does not lead to wind erosion of the soil at the study site because that surface is more influenced by the vegetation cover than by the soil characteristics.

  15. The magnetic susceptibility of European agricultural soils

    Fabian, K.; Reimann, C.

    2012-04-01

    The GEMAS (Geochemical mapping of agricultural soils) project, a cooperation project between EuroGeoSurveys and Eurometaux, aims at providing soil quality data for Europe. Samples of arable soil were taken during 2008 at an average density of 1 site/2500 km2 covering the member states of the European Union (except Malta and Romania) and several neighbouring countries (e.g., Norway, Serbia, Ukraine). While the primary aim of the GEMAS project is to produce REACH (Registration, Evaluation and Authorisation of CHemicals - EC, 2006) consistent soil geochemistry data at the continental scale, the data set is also optimally apt to provide the first continental scale overview of magnetic properties in European soils. Soil samples from the upper 20 cm were taken as composites from 5 sites spread over a ca. 100 m2 area in a large agricultural field (Ap-sample). The samples were air dried and sieved to pass a 2 mm nylon screen. Weight normalized magnetic susceptibility of these dried samples was measured using a Sapphire Instruments SI2B susceptibility meter with dynamic background removal. The here presented maps of magnetic susceptibility in relation to geochemical composition and geological structures for the first time allow to outline the large scale influence of tectonics and climate on magnetic mineral concentration in European soils. The data set also provides the background variability for regional studies aiming to relate magnetic susceptibility of soils to local contamination sources.

  16. Soil-frost-enabled soil-moisture-precipitation feedback over northern high latitudes

    Hagemann, Stefan; Blome, Tanja; Ekici, Altug; Beer, Christian

    2016-07-01

    Permafrost or perennially frozen ground is an important part of the terrestrial cryosphere; roughly one quarter of Earth's land surface is underlain by permafrost. The currently observed global warming is most pronounced in the Arctic region and is projected to persist during the coming decades due to anthropogenic CO2 input. This warming will certainly have effects on the ecosystems of the vast permafrost areas of the high northern latitudes. The quantification of such effects, however, is still an open question. This is partly due to the complexity of the system, including several feedback mechanisms between land and atmosphere. In this study we contribute to increasing our understanding of such land-atmosphere interactions using an Earth system model (ESM) which includes a representation of cold-region physical soil processes, especially the effects of freezing and thawing of soil water on thermal and hydrological states and processes. The coupled atmosphere-land models of the ESM of the Max Planck Institute for Meteorology, MPI-ESM, have been driven by prescribed observed SST and sea ice in an AMIP2-type setup with and without newly implemented cold-region soil processes. Results show a large improvement in the simulated discharge. On the one hand this is related to an improved snowmelt peak of runoff due to frozen soil in spring. On the other hand a subsequent reduction in soil moisture enables a positive feedback to precipitation over the high latitudes, which reduces the model's wet biases in precipitation and evapotranspiration during the summer. This is noteworthy as soil-moisture-atmosphere feedbacks have previously not been the focus of research on the high latitudes. These results point out the importance of high-latitude physical processes at the land surface for regional climate.

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

    Goulet, France

    2000-07-01

    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.

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

    F. Anctil

    2008-05-01

    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.

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

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

    2010-12-01

    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 μM 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

  20. Robert Frost on Writing.

    Barry, Elaine

    This book is a collection of Frost's letters, reviews, introductions, lectures, and interviews on writing dating back to 1913. It provides Frost's view of literature, and its relation to language and social order. Part one, "Frost as a Literary Critic," discusses the scope of Frost's criticism and Frost as both critical theorist and…

  1. Preliminary soil-slip susceptibility maps, southwestern California

    Morton, Douglas M.; Alvarez, Rachel M.; Campbell, Russell H.; Digital preparation by Bovard, Kelly R.; Brown, D.T.; Corriea, K.M.; Lesser, J.N.

    2003-01-01

    This group of maps shows relative susceptibility of hill slopes to the initiation sites of rainfall-triggered soil slip-debris flows in southwestern California. As such, the maps offer a partial answer to one part of the three parts necessary to predict the soil-slip/debris-flow process. A complete prediction of the process would include assessments of “where”, “when”, and “how big”. These maps empirically show part of the “where” of prediction (i.e., relative susceptibility to sites of initiation of the soil slips) but do not attempt to show the extent of run out of the resultant debris flows. Some information pertinent to “when” the process might begin is developed. “When” is determined mostly by dynamic factors such as rainfall rate and duration, for which local variations are not amenable to long-term prediction. “When” information is not provided on the maps but is described later in this narrative. The prediction of “how big” is addressed indirectly by restricting the maps to a single type of landslide process—soil slip-debris flows. The susceptibility maps were created through an iterative process from two kinds of information. First, locations of sites of past soil slips were obtained from inventory maps of past events. Aerial photographs, taken during six rainy seasons that produced abundant soil slips, were used as the basis for soil slip-debris flow inventory. Second, digital elevation models (DEM) of the areas that were inventoried were used to analyze the spatial characteristics of soil slip locations. These data were supplemented by observations made on the ground. Certain physical attributes of the locations of the soil-slip debris flows were found to be important and others were not. The most important attribute was the mapped bedrock formation at the site of initiation of the soil slip. However, because the soil slips occur in surficial materials overlying the bedrocks units, the bedrock formation can only serve as

  2. Soil susceptibility to accelerated hydric erosion: geotechnical evaluation of cut slopes in residual soil profiles

    Taciano Oliveira da Silva

    2015-10-01

    Full Text Available The experimental research program was developed in the Alto Paraopeba region, state of Minas Gerais, Southeastern Brazil. The main objective was to promote the geotechnical evaluation of soil samples from four cut slopes in residual soil profiles of highways and local secondary roads in order to assess the potential of the anthropic impact on the soil susceptibility to accelerated erosion processes. Soil samples were named: red residual soil (RRS; pink residual soil (PRS; yellow residual soil (YRS; and white residual soil (WRS. The methodology used consisted of geotechnical characterization tests, infiltration rate and modified mass loss by immersion tests performed on soil samples from these profiles, using the physical parameters and indirect assessment of erodibility proposed in 2000 by Bastos et al. The results of indirect assessment of erodibility, which were derived from tests based on the MCT methodology, highlighted the different susceptibility of the investigated soils to hydric erosion. The parameters proposed by the referred authors were complementary to conventional criteria for an adequate classification of tropical soils into their respective classes of erodibility. Among the tested soil samples, the highest erodibility was associated with the YRS and PRS, respectively, in the natural and pre-moistened conditions, as well as it was not detected erodibility in the RRS and WRS.

  3. Magnetic Susceptibility of Soil to Differentiate Soil Environments in Southern Brazil

    Priscila Vogelei Ramos

    Full Text Available ABSTRACT The interest in new techniques to support digital soil mapping (DSM is increasing. Numerous studies pointed out that the measure of magnetic susceptibility (MS can be extremely useful in the identification of properties related with factors and processes of soil formation, applied to soil mapping. This study addressed the effectiveness of magnetic soil susceptibility to identify and facilitate the distinction of different pedogenic environments of a representative hillslope in the highland Planalto Médio in the state of Rio Grande do Sul (RS, Brazil. In a 350-ha area in the municipality of Santo Augusto, RS, a representative transect was selected, trenches opened for soil characterization and 29 grid points marked at regular distances of 50 m, where soil samples were collected (layers 0.00-0.05, 0.05-0.15, 0.15-0.30, and 0.30-0.60 m to analyze soil properties. Data from the transect samples were subjected to descriptive statistics. Limits of the pedogenetic environments along the slope were identified by the Split Moving Window (SMW Boundary Analysis. The combined use of soil magnetic susceptibility and the SMW technique was effective in identifying different pedogenetic environments in the study area.

  4. Frost risks in the Mantaro river basin

    G. Trasmonte

    2008-04-01

    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.

  5. Frost on Utopia Planitia

    1977-01-01

    This Viking Lander 2 picture from Utopia Planitia shows the first clear indication of frost accumulation on the Martian surface seen by lander cameras. The picture, looking due north, was obtained with a blue filter at 12:59 p.m. local lander time, Sept. 13, 1977. The season is late winter. Frost appears as a white accumulation around the bottom of rocks, in a trench dug by the lander sampler arm, and in scattered patches on the darker surface. The shadow of the lander, including the camera (center) and the meteorology boom (left), appears in foreground. As the sun moves, the shadow is moving from left to right, exposing areas covered by frost and previously protected from the sun by the lander shadow. (Another image taken one-half hour later suggests the frost patches have become smaller.) Apparently frost, formed during the Martian night, at least partially disappears during the warmer daytime. The composition of the frost, whether carbon dioxide or water or a mixture of the two (CO2 clathrate), is not known. Measurements from the meteorology instrument indicate minimum nighttime temperatures of 160 Kelvin (-171 Fahrenheit). At the time the image was taken, the temperature had risen to 175 Kelvin (-144 Fahrenheit). The atmospheric pressure was 8.835 millibars. This combination of pressure and temperature are inconsistent with carbon dioxide frost formation, but plausible near-surface mechanisms might have resulted in conditions favorable for CO2 frost formation. Viking orbiter thermal mapping and water vapor instruments indicate temperatures might have been slightly lower than measured by the lander, suggesting that the frost is more likely CO2 than H20. A remote, but possible, explanation is that the material is an extremely bright dust deposit. Color images to be taken will be able to discount this interpretation. The mechanism for frost deposition is unknown. Possibilities include formation directly on the surface, precipitation as snow, or material blown to

  6. [Heavy Metals Accmultio in the Caofeidian Reclamation Soils: Indicated by Soil Magnetic Susceptibility].

    Xue, Yong; Zhou, Qian; Li, Yuan; Zhang, Hai-bo; Hu, Xue-feng; Luo, Yong-ming

    2016-04-15

    The environmental magnetism method has been widely applied to identify soil heavy metal pollution, which is characterized by simplicity, efficiency, non-destructivity and sensitivity. The present study used magnetic susceptibility to assess the accumulation of heavy metals in soils of the Caofeidian industrial zone which is a typical reclamation area in northern China. The study area was divided into three sub-zones based on the function, including industrial zone, living zone, natural tidal flat and wetland. A total of 35 topsoil samples (0-10 cm) and 3 soil profiles were collected from the three sub-zones. Magnetic susceptibility (X(lf)), iron oxide (Fe2O3) contents and heavy metals contents (Cr, Ni, Cu, Zn, As, Pb, Mn and V) of the samples were analyzed. The results showed that X(lf) values and heavy metals contents exhibited higher spatial variability in the top soil of the industrial zone, indicating the severe impacts of industrial activities. In the soil profiles of the industrial and living zones, all heavy metals were enriched to different degrees in the upper layer (0-20 cm). However, there was no significant change of heavy metal contents in the soil profiles of tidal flat which was far from the industrial area. The X(lf) value was significantly (P soil. This indicated that X(lf) could be used as an indicator for heavy metal accumulation in the industrial zone. However, the X(lf) value was not suitable to be an indicator to show the heavy metal accumulation in the soils of living zone and natural tidal flat. This might be associated with the different sources of magnetic materials among the different sub-zones and the special characteristics of the soils in the tidal flat and wetland.

  7. Infrared radiation method for measuring ice segregation temperature of artificially frozen soils

    Zhou Guoqing; Zhang Qi; Xu Zhiwei; Zhou Yang

    2012-01-01

    In order to study the evolution of the freezing fringe and final lenses of frost susceptible soils and advance the understanding of frost heave and mechanism of frost heave control,we used an open one-dimensional frost heave test system of infrared radiation technology,instead of a traditional thermistor method.Temperatures of the freezing fringe and segregated ice were measured in a non-contact mode.The results show that accurate and precise temperatures of ice segregation can be obtained by infrared thermal imaging systems.A self-developed inversion program inverted the temperature field of frozen soils.Based on our analysis of temperature variation in segregated ice and our study of the relationship between temperature and rate of ice segregation in cooling and warming processes during intermittent freezing,the mechanism of decreasing frost heave of frozen soils by controlling the growth of final lenses with an intermittent freezing mode,can be explained properly.

  8. Classification of soil magnetic susceptibility and prediction of metal detector performance: case study of Angola

    Preetz, Holger; Altfelder, Sven; Hennings, Volker; Igel, Jan

    2009-05-01

    Soil magnetic properties can seriously impede the performance of metal detectors used in landmine clearance operations. For a proper planning of clearance operations pre-existing information on soil magnetic susceptibility can be helpful. In this study we briefly introduce a classification system to assess soil magnetic susceptibilities from geoscientific maps. The classification system is based on susceptibility measurements conducted on archived lateritic soil samples from 15 tropical countries. The system is applied to a soil map of Angola, resulting in a map that depicts soil magnetic susceptibilities as a worst case scenario. An additional layer depicting the surveyed mine affected communities in Angola is added to the map, which demonstrates that a large number of those are located in areas where soil is expected to impede metal detector performance severely.

  9. Frost Effects Research Facility

    Federal Laboratory Consortium — Full-scale study in controlled conditionsThe Frost Effects Research Facility (FERF) is the largest refrigerated warehouse in the United States that can be used for a...

  10. Frost Effects Research Facility

    Federal Laboratory Consortium — Full-scale study in controlled conditions The Frost Effects Research Facility (FERF) is the largest refrigerated warehouse in the United States that can be used for...

  11. Determination of allowable subgrade frost heave with the pavement roughness index in numerical analysis

    HongYan Ma; Feng Zhang; DeCheng Feng; Bo Lin

    2015-01-01

    Frost heave is an upward swelling of soil during cryogenic conditions in cold regions. It is caused by the accumulation of ice crystals in subgrade soil, which grow upwards when freezing temperatures penetrate into the subgrade. This study establishes the allowable soil subgrade frost heave based on the roughness standard of asphalt pavement in China, and aims to balance the pavement design and frost heave resistance of subgrades in cold regions. We formulated a mechanical model of pavement supported by the boundary conditions of differential frost heave, based on the elastic layered system theory. The differential soil subgrade frost heave was modeled as a sinusoidal function, and the allowable frost heave and the roughness index were modeled as the displacement boundaries for the top and bottom of the pavement structure. Then the allowable frost heave was back-calculated according to the roughness standard. Numerical results show that the allowable frost heave depends on the pavement structure, material properties, the highway grade, and other factors. In order to ensure that the actual soil subgrade frost heave is lower than the allowable frost heave, pavement structures and materials need to be selected and designed carefully. The numerical method proposed here can be applied to establish the frost heave re-sistance of subgrade when the pavement structure and materials are determined.

  12. Frost hardiness of tree species is independent of phenology and macroclimatic niche

    M Hofmann; H Bruelheide

    2015-03-01

    The differences in timing in bud burst between species have been interpreted as an adaptation to late frost events in spring. Thus, it has been suggested that the degree of frost susceptibility of leaves is species-specific and depends on the species’ phenology and geographic distribution range. To test for relationships between frost tolerance and phenology as well as between frost tolerance and distribution range across Central European tree species, we studied the frost hardiness of closed buds before bud burst and of freshly opened buds at the time of bud burst. We hypothesized that species with early bud burst and species distributed in eastern and northern areas were more frost tolerant than species with late bud burst and species distributed in western and southern areas. Frost hardiness was estimated by exposing twigs to 11 frost temperatures between −4°C and −80°C and by assessing tissue damage by the electrolyte leakage method. In contrast to our hypotheses, neither frost hardiness of closed buds nor frost hardiness of freshly opened buds were related to any variable describing species’ macroclimatic niche. Furthermore, frost hardiness of freshly opened buds did not differ among species. Thus, the investigated species with early bud burst take higher risks of frost damage than the species with late bud bursts. These findings indicate that frost hardiness might not play the key role in limiting the geographic distribution ranges previously anticipated.

  13. Coatings to prevent frost

    Lusada, Ricardo; Holberg, Stefan; Bennedsen, Jeanette Marianne Dalgaard

    2016-01-01

    environment, on surfaces providing a water contact angle hysteresis of about 10° and receding water contact angles higher than 90°, a rate for the growth of the average radius of the frozen area of about 2 µm/s was observed. Submitting the surface to an airflow of 1 m/s led to faster frost spreading in flow...

  14. Crushed aggregates for roads and their properties for frost protection

    Kuznetsova, Elena; Willy Danielsen, Svein

    2015-04-01

    Crushed aggregates for roads and their properties for frost protection Elena Kuznetsova, NTNU and Svein Willy Danielsen, SINTEF With natural (fluvial, glaciofluvial) sand/gravel resources being rapidly depleted in many countries, the last decade has seen a significant trend towards using more alternative materials for construction purpose. In Norway the development and implementation of crushed aggregate technology has been the most important way to get around the problem with increased resource scarcity. Today Norway is one the European countries with the highest percentage of crushed/manufactured aggregates. A crushed product will reveal a different particle size distribution, a sharper, more angular particle shape, and not least - a significantly different mineral composition. The latter may often be characterised by more polymineral composition, and it will also much more depend on the local bedrock. When handled with care and knowledge, these differences can give the user a lot of new opportunities relating to materials design. Norwegian road construction practice has changed significantly during the last 40 years due to the replacement of gravel by crushed rock materials in the granular layers of the pavements. The use of non-processed rock materials from blasting was allowed in the subbase layer until 2012. This was a reason for a lot of problems with frost heaving due to inhomogeneity of this material, and in practice it was difficult to control the size of large stones. Since 2012 there is a requirement that rock materials for use in the subbase layer shall be crushed (Handbook N200, 2014). During the spring 2014 The Norwegian Public Roads Administration introduced a new handbook with requirements for roads construction in Norway, including new specifications for the frost protection layer. When pavements are constructed over moist and/or frost susceptible soils in cold and humid environments, the frost protection layer also becomes a very important part

  15. Frost formation with salt

    Guadarrama-Cetina, J.; Mongruel, A; González-Viñas, W; Beysens, D. A.

    2015-01-01

    The formation of frost in presence of salt (NaCl) crystal is experimentally investigated on a hydrophobic surface. It presents several remarkable features due to the interplay of salty-water saturation pressure evolution, initially lower than the saturation pressure of ice and water, and the percolating propagation of ice dendrites from defects throughout the supercooled water droplet pattern. In particular, it is remarkable that nucleation of supercooled water and/or ice is prevented around ...

  16. Pinhole test for identifying susceptibility of soils to piping erosion: effect water quality and hydraulic head

    Nadal Romero, E.; Verachtert, E.; Poesen, J.

    2009-07-01

    Piping has been observed in both natural and soils, as well as under different types of land uses and vegetation covers. Despite its importance, no standard widely-applied methodology exists to assess susceptibility of soils to piping. This study aims at evaluating the pinhole test for assessing the susceptibility of soils to piping under different conditions. More precisely, the effects of hydraulic head and water quality are being assessed. Topsoil samples (remoulded specimens) with a small range of water contents were taken in Central Belgium (Heverlee) and the susceptibility of these soil samples are investigated under standardized laboratory conditions with a pinhole test device. Three hydraulic heads (50,180 and 380 mm) and two water qualities (tap and distilled water) were used, reflecting dominant field conditions. (Author) 6 refs.

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

    P. Nazarok

    2014-03-01

    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.

  18. Influence of Soil Temperature on Meloidogyne incognita Resistant and Susceptible Cotton, Gossypium hirsutum

    Carter, William W.

    1982-01-01

    The degree of resistance by a cotton plant to Meloidogyne incognita is affected by soil temperature, particularly in moderately resistant cultivars, The total number of nematodes in the resistant and moderately resistant rools at 35 C was equal to, or greater than, the number in susceptible roots at 20, 25, or 30 C. A shift in numbers to developing and egg-bearing forms of nematodes in the susceptible cultivar as tentperature increased indicates development was affected by temperature rather ...

  19. Using magnetic susceptibility to discriminate between soil moisture regimes in selected loess and loess-like soils in northern Iran

    Valaee, Morteza; Ayoubi, Shamsollah; Khormali, Farhad; Lu, Sheng Gao; Karimzadeh, Hamid Reza

    2016-04-01

    This study used discriminant analysis to determine the efficacy of magnetic measures for discriminating between four soil moisture regimes in northern Iran. The study area was located on loess deposits and loess-like soils containing similar parent material. Four soil moisture regimes including aridic, xeric, udic, and aquic were selected. A total of 25 soil profiles were drug from each regime and composite soil samples were collected within the moisture control section. A set of magnetic measures including magnetic susceptibility at low (χlf) and high (χhf) frequencies, frequency-dependent magnetic susceptibility (χfd), saturation isothermal remnant magnetization (SIRM), and isothermal remnant magnetization (IRM100 mT, IRM 20 mT) were measured in the laboratory. Dithionite citrate bicarbonate (Fed) and acid oxalate (Feo) contents of all soil samples were also determined. The lowest and highest χlf and χhf were observed in aquic and udic moisture regimes, respectively. A similar trend was obtained for Fed and Fed-Feo. The significant positive correlation between Fed and SIRM (r = 0.60; P < 0.01) suggested the formation of stable single domains (SSD) due to pedogenic processes. The results of discriminant analysis indicated that a combination of magnetic measures could successfully discriminate between the selected moisture regimes in the study area (average accuracy = 80%). It can thus be concluded that magnetic measures could be applied as a powerful indicator for differentiation of soil moisture regimes in the study area.

  20. Experimental study of frost heaving force based on transient shock response using piezoceramic sensors

    Wang, Ruolin; Peng, Tongxiao; Wang, Ming L.

    2016-04-01

    In seasonally frozen soil regions, the frost heaving problem made it difficult to monitor or evaluate the pile safety for long term. So far, no mature tool can be utilized to monitor the frost heaving force, which was unevenly distributed along the pile. In this paper, a piezoceramic sensing based transient excitation response approach was proposed to monitor the frost heaving force in real time. Freeze-thaw cycles can result in great changes of soil engineering properties, including the frost heaving force. So, the freeze-thaw cycle was repeated fourth to study its effect. In the experiment, transient horizontal shock on the top of the pile will be detected by the 6 PZT sensors glued on the pile. The signal data received by the 6 PZT sensors can be used to illustrate the frost heaving force distribution along the pile. Moisture content effect is also one of the important reasons that cause the variation of soil mechanical properties. So three different moisture content (6%, 12%, 18%) testing soil were used in this experiment to detect the variance of the frost heaving force. An energy indicator was developed to quantitatively evaluate the frost heaving force applied on the pile. The experimental results showed that the proposed method was effective in monitoring the uneven distribution of frost heaving force along the pile.

  1. Study on preventing frost heave methods for highway foundation in seasonal frozen area

    Xin LI

    2006-01-01

    In order to resolve the frost-heave problem of highway foundation, firstly, the author discussed the law to frost heave of highway roadbed and gave an analysis on its influencing factors, such as soil, water and temperature. Meanwhile, sand clay and silt are given a classification according to frost heave ratio. Secondly, the roadbed frozen damage shows to frost heave and froze boiling based on the frost heave law and its influencing factors. In addition, taking some highway as an example and some principle suggestion was given through the theory on providing frostbite methods for highway foundation frost heave in seasonal frozen area. Specially, an effective method, STYROFOAM extruded polystyrene foam was introduced.

  2. Uncertainty of spatial distributions of soil magnetic susceptibility in areas of different type of land cover and anthropogenic pressure

    Zawadzki, Jaroslaw; Fabijańczyk, Piotr

    2016-04-01

    There is still a high interest in the improvement of soil magnetometry procedures that would increase its accuracy. Soil magnetometry is usually used as a fast screening method that is used to assess the degree of soil pollution. As the magnetometric measurements do not provide the exact information about the concentration of elements in soil, it is very important to determine the uncertainty of the spatial distributions of soil magnetic susceptibility. The goal of this study was to analyze and present geostatistical methods of assessing the uncertainty of spatial distribution of soil magnetic susceptibility in areas of different land cover and anthropogenic pressure. In particular, spatial distributions of magnetic susceptibility measured on the soil surface using a MS2D Bartington device were calculated using indicator methods that make it possible to calculate the probability of exceeding the critical levels of soil magnetic susceptibility. Measurements were performed in areas located in the Upper Silesian Industrial Area in Poland, and in Norway. In these areas soil magnetic susceptibility was measured on the soil surface using a MS2D Bartington device. Additionally, soil samples were taken in order to perform chemical measurements that included the determination of a concentration of selected elements. Acknowledgment The research leading to these results has received funding from the Polish-Norwegian Research Programme operated by the National Centre for Research and Development underthe Norwegian Financial Mechanism 2009-2014 in the frame of Project IMPACT - Contract No Pol-Nor/199338/45/2013.

  3. Mineralogy, size, morphology and porosity of aggregates and their relationship with soil susceptibility to water erosion

    Figueiredo, M. do A, E-mail: mucfig@hotmail.com; Augustin, C.H.R.R. [Instituto de Geociencias, Universidade Federal de Minas Gerais, Departamento de Geografia (Brazil)], E-mail: mucfig@hotmail.com; Fabris, J.D. [Universidade Federal de Minas Gerais, Departamento de Quimica, Instituto de Ciencias Exatas (Brazil)], E-mail: fabris@dedalus.lcc.ufmg.br

    1999-11-15

    Soil erosion has been considered as the main process related to losses of soil mass and decrease of productivity in cultivated lands as well as on e of the most important processes in landscape evolution. Attention has been paid to many pedological variables affecting intensity of erosion, but little to the influence of iron compounds on the type, size, shape and porosity of soil aggregates. In the present study, three lithopedodomains which were assumed to be closely related to the dominant lithology of the soil parent material, varying in the degree of water erosion intensity, were selected for further analysis which focused mainly on the influence of iron oxide mineralogy on the soil aggregation. Powder X-ray diffractometry, 80 K Moessbauer data and SEM images are used to correlate all these variables with observed erosion activity in the field. The present data indicate that the more the soil is rich in iron (hematite and/or goethite) or aluminium (gibbsite) (hydr)oxide, the smaller are its aggregates and is porous. Soils derived from metabasic rocks are much more susceptible to collapse under wetting than those from other lithologies. They have the highest iron and clay content. Schist-derived soil is richer in muscovite, has bigger aggregates and porous and are less prone to collapse, while the granite-derived soil presents relatively intermediate resistance, when humid.

  4. Influence of Soil Temperature on Meloidogyne incognita Resistant and Susceptible Cotton, Gossypium hirsutum.

    Carter, W W

    1982-07-01

    The degree of resistance by a cotton plant to Meloidogyne incognita is affected by soil temperature, particularly in moderately resistant cultivars, The total number of nematodes in the resistant and moderately resistant rools at 35 C was equal to, or greater than, the number in susceptible roots at 20, 25, or 30 C. A shift in numbers to developing and egg-bearing forms of nematodes in the susceptible cultivar as tentperature increased indicates development was affected by temperature rather than by genetic resistance mechanisms. However, the nematode resistant cultivar did not support maturation of nematodes until a soil tempurature of 35 C was attained. This indicated that resistance mechanisms are partially repressed at 35 C and differences in nematode development cannot be explained in terms of accumulated heat units. The moderately resistant cultivar was significantly more sensitive to the effects of high temperature than was the resistant cultivar.

  5. Subsoil compaction in Flanders: from soil map to susceptibility map and risk map for subsoil compaction

    van de Vreken, Philippe; van Holm, Lieven; Diels, Jan; van Orshoven, Jos

    2010-05-01

    In contrast to topsoil compaction, which can be remediated by normal soil tillage and natural loosening processes, subsoil compaction must be considered as a long term threat to soil productivity as this form of compaction is much more persistent and not easy to alleviate. Therefore we focused on subsoil compaction with a view to demarcate areas prone to soil compaction in Flanders, Belgium. The susceptibility of soil material to compaction is inversely related to its structural strength which can be expressed in terms of precompression stress (PCS). In order to construct maps of subsoil susceptibility we upgraded the soil map of Flanders, originally printed at a scale of 1:20.000, by attributing a ‘typical' PCS-value to the legend units. These PCS-values were estimated by means of pedotransfer functions (PTFs), valid either at pF 1.8 or pF 2.5, elaborated from PCS-measurements on soils in Germany by Lebert and Horn (1991). Predictor values for the PTFs were supplied by or derived by means of other PTFs from a historical database of georeferenced soil profiles, which were analysed between 1947 and 1971. After regional stratification, soil profiles with associated horizons were linked to soil map units based on corresponding classification units. Next, for each map unit the horizon at 40 cm of depth was selected and its characteristics retrieved for use in the PTFs. The two resulting PCS-maps (pF 1.8 or 2.5) show the susceptibility to compaction of almost uncompacted or little compacted arable soils as they were present in the period 1950-1970, when the wheel loads of the agricultural equipment of that time were much lower compared to the wheel loads that are common today. Both maps of inherent susceptibility at fixed pF were combined into a ‘hybrid map' of the inherent susceptibility to subsoil compaction in spring, when the groundwater table is at its highest level and correspondingly also the susceptibility to compaction is highest. Each soil map unit was

  6. Managing potato biodiversity to cope with frost risk in the high Andes: a modeling perspective.

    Condori, Bruno; Hijmans, Robert J; Ledent, Jean Francois; Quiroz, Roberto

    2014-01-01

    Austral summer frosts in the Andean highlands are ubiquitous throughout the crop cycle, causing yield losses. In spite of the existing warming trend, climate change models forecast high variability, including freezing temperatures. As the potato center of origin, the region has a rich biodiversity which includes a set of frost resistant genotypes. Four contrasting potato genotypes--representing genetic variability--were considered in the present study: two species of frost resistant native potatoes (the bitter Solanum juzepczukii, var. Luki, and the non-bitter Solanum ajanhuiri, var. Ajanhuiri) and two commercial frost susceptible genotypes (Solanum tuberosum ssp. tuberosum var. Alpha and Solanum tuberosum ssp. andigenum var. Gendarme). The objective of the study was to conduct a comparative growth analysis of four genotypes and modeling their agronomic response under frost events. It included assessing their performance under Andean contrasting agroecological conditions. Independent subsets of data from four field experiments were used to parameterize, calibrate and validate a potato growth model. The validated model was used to ascertain the importance of biodiversity, represented by the four genotypes tested, as constituents of germplasm mixtures in single plots used by local farmers, a coping strategy in the face of climate variability. Also scenarios with a frost routine incorporated in the model were constructed. Luki and Ajanhuiri were the most frost resistant varieties whereas Alpha was the most susceptible. Luki and Ajanhuiri, as monoculture, outperformed the yield obtained with the mixtures under severe frosts. These results highlight the role played by local frost tolerant varieties, and featured the management importance--e.g. clean seed, strategic watering--to attain the yields reported in our experiments. The mixtures of local and introduced potatoes can thus not only provide the products demanded by the markets but also reduce the impact of frosts

  7. Managing potato biodiversity to cope with frost risk in the high Andes: a modeling perspective.

    Bruno Condori

    Full Text Available Austral summer frosts in the Andean highlands are ubiquitous throughout the crop cycle, causing yield losses. In spite of the existing warming trend, climate change models forecast high variability, including freezing temperatures. As the potato center of origin, the region has a rich biodiversity which includes a set of frost resistant genotypes. Four contrasting potato genotypes--representing genetic variability--were considered in the present study: two species of frost resistant native potatoes (the bitter Solanum juzepczukii, var. Luki, and the non-bitter Solanum ajanhuiri, var. Ajanhuiri and two commercial frost susceptible genotypes (Solanum tuberosum ssp. tuberosum var. Alpha and Solanum tuberosum ssp. andigenum var. Gendarme. The objective of the study was to conduct a comparative growth analysis of four genotypes and modeling their agronomic response under frost events. It included assessing their performance under Andean contrasting agroecological conditions. Independent subsets of data from four field experiments were used to parameterize, calibrate and validate a potato growth model. The validated model was used to ascertain the importance of biodiversity, represented by the four genotypes tested, as constituents of germplasm mixtures in single plots used by local farmers, a coping strategy in the face of climate variability. Also scenarios with a frost routine incorporated in the model were constructed. Luki and Ajanhuiri were the most frost resistant varieties whereas Alpha was the most susceptible. Luki and Ajanhuiri, as monoculture, outperformed the yield obtained with the mixtures under severe frosts. These results highlight the role played by local frost tolerant varieties, and featured the management importance--e.g. clean seed, strategic watering--to attain the yields reported in our experiments. The mixtures of local and introduced potatoes can thus not only provide the products demanded by the markets but also reduce the

  8. Comparison of human and soil Candida tropicalis isolates with reduced susceptibility to fluconazole.

    Yun-Liang Yang

    Full Text Available Infections caused by treatment-resistant non-albicans Candida species, such as C. tropicalis, has increased, which is an emerging challenge in the management of fungal infections. Genetically related diploid sequence type (DST strains of C. tropicalis exhibiting reduced susceptibility to fluconazole circulated widely in Taiwan. To identify the potential source of these wildly distributed DST strains, we investigated the possibility of the presence in soil of such C. tropicalis strains by pulsed field gel electrophoresis (PFGE and DST typing methods. A total of 56 C. tropicalis isolates were recovered from 26 out of 477 soil samples. Among the 18 isolates with reduced susceptibility to fluconazole, 9 belonged to DST149 and 3 belonged to DST140. Both DSTs have been recovered from our previous studies on clinical isolates from the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (TSARY program. Furthermore, these isolates were more resistant to agricultural azoles. We have found genetically related C. tropicalis exhibiting reduced susceptibility to fluconazole from the human hosts and environmental samples. Therefore, to prevent patients from acquiring C. tropicalis with reduced susceptibility to azoles, prudent use of azoles in both clinical and agricultural settings is advocated.

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

    Martina Kyselková

    2013-08-01

    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.

  10. Effect of suction-dependent soil deformability on landslide susceptibility maps

    Lizarraga, Jose J.; Buscarnera, Giuseppe; Frattini, Paolo; Crosta, Giovanni B.

    2016-04-01

    This contribution presents a physically-based, spatially-distributed model for shallow landslides promoted by rainfall infiltration. The model features a set of Factor of Safety values aimed to capture different failure mechanisms, namely frictional slips with limited mobility and flowslide events associated with the liquefaction of the considered soils. Indices of failure associated with these two modes of instability have been derived from unsaturated soil stability principles. In particular, the propensity to wetting-induced collapse of unsaturated soils is quantified through the introduction of a rigid-plastic model with suction-dependent yielding and strength properties. The model is combined with an analytical approach (TRIGRS) to track the spatio-temporal evolution of soil suction in slopes subjected to transient infiltration. The model has been tested to reply the triggering of shallow landslides in pyroclastic deposits in Sarno (1998, Campania Region, Southern Italy). It is shown that suction-dependent mechanical properties, such as soil deformability, have important effects on the predicted landslide susceptibility scenarios, resulting on computed unstable zones that may encompass a wide range of slope inclinations, saturation levels, and depths. Such preliminary results suggest that the proposed methodology offers an alternative mechanistic interpretation to the variability in behavior of rainfall-induced landslides. Differently to standard methods the explanation to this variability is based on suction-dependent soil behavior characteristics.

  11. The periglacial engine of mountain erosion – Part 1: Rates of frost cracking and frost creep

    Andersen, Jane Lund; Egholm, David Lundbek; Knudsen, Mads Faurschou

    2015-01-01

    With accelerating climate cooling in the late Cenozoic, glacial and periglacial erosion became more widespread on the surface of the Earth. The resultant shift in erosion patterns significantly changed the large-scale morphology of many mountain ranges worldwide. Whereas the glacial fingerprint....... Here we investigate the important role that periglacial processes also play in less steep parts of mountain landscapes. Understanding the influences of frost-driven processes in low-relief areas requires a focus on the consequences of an accreting soil mantle, which characterises such surfaces. We...

  12. Identification of soil bacteria susceptible to TiO2 and ZnO nanoparticles.

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

    2012-09-01

    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.

  13. Neural Network-Based Model for Landslide Susceptibility and Soil Longitudinal Profile Analyses

    Farrokhzad, F.; Barari, Amin; Choobbasti, A. J.

    2011-01-01

    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...... studies in landslide susceptibility zonation....

  14. The Physics of Frost Heave and Ice-Lens Growth

    Peppin, Stephen S. L.

    2013-01-01

    The principle cause of frost heave is the formation of segregated ice-ice lenses-in freezing soil columns. Despite much experimental and theoretical work, there remain many questions about the fundamental process by which this occurs. Frost-heave models fall into two main classes: capillary and frozen-fringe models. Which model is appropriate depends on whether there is a frozen fringe; these are difficult to observe but some experimental evidence does exist. Recent advances have revitalized the capillary model, such as the engulfment model and the concept of geometrical supercooling. Key experimental and theoretical challenges remain to be resolved. © Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved.

  15. Morphometry and land cover based multi-criteria analysis for assessing the soil erosion susceptibility of the western Himalayan watershed.

    Altaf, Sadaff; Meraj, Gowhar; Romshoo, Shakil Ahmad

    2014-12-01

    Complex mountainous environments such as Himalayas are highly susceptibility to natural hazards particular those that are triggered by the action of water such as floods, soil erosion, mass movements and siltation of the hydro-electric power dams. Among all the natural hazards, soil erosion is the most implicit and the devastating hazard affecting the life and property of the millions of people living in these regions. Hence to review and devise strategies to reduce the adverse impacts of soil erosion is of utmost importance to the planners of watershed management programs in these regions. This paper demonstrates the use of satellite based remote sensing data coupled with the observational field data in a multi-criteria analytical (MCA) framework to estimate the soil erosion susceptibility of the sub-watersheds of the Rembiara basin falling in the western Himalaya, using geographical information system (GIS). In this paper, watershed morphometry and land cover are used as an inputs to the MCA framework to prioritize the sub-watersheds of this basin on the basis of their different susceptibilities to soil erosion. Methodology included the derivation of a set of drainage and land cover parameters that act as the indicators of erosion susceptibility. Further the output from the MCA resulted in the categorization of the sub-watersheds into low, medium, high and very high erosion susceptibility classes. A detailed prioritization map for the susceptible sub-watersheds based on the combined role of land cover and morphometry is finally presented. Besides, maps identifying the susceptible sub-watersheds based on morphometry and land cover only are also presented. The results of this study are part of the watershed management program in the study area and are directed to instigate appropriate measures to alleviate the soil erosion in the study area.

  16. Mapping Statistical Characteristics of Frosts in Iran

    P. Mahmoudi

    2014-10-01

    Full Text Available 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

  17. Spatial variability of soil magnetic susceptibility in an agricultural field located in Eastern Ukraine

    Menshov, Oleksandr; Pereira, Paulo; Kruglov, Oleksandr

    2015-04-01

    Magnetic susceptibility (MS) have been used to characterize soil properties. It gives an indirect information about heavy metals content and degree of human impacts on soil contamination derived from atmospheric pollution (Girault et al., 2011). This method is inexpensive in relation to chemical analysis and very useful to track soil pollution, since several toxic components deposited on soil surface are rich in particulates produced by oxidation processes (Boyko et al., 2004; Morton-Bernea et al., 2009). Thus, identify the spatial distribution of MS is of major importance, since can give an indirect information of high metals content (Dankoub et al., 2012). This allows also to distinguish the pedogenic and technogenic origin magnetic signal. For example Ukraine chernozems contain fine-grained oxidized magnetite and maghemite of pedogenic origin formed by weathering of the parent material (Jeleńska et al., 2004). However, to a correct understanding of variables distribution, the identification of the most accurate interpolation method is fundamental for a better interpretation of map information (Pereira et al., 2013). The objective of this work is to study the spatial variability of soil MS in an agricultural fields located in the Tcherkascy Tishki area (50.11°N, 36.43 °E, 162 m a.s.l), Ukraine. Soil MS was measured in 77 sampling points in a north facing slope. To estimate the best interpolation method, several interpolation methods were tested, as inverse distance to a weight (IDW) with the power of 1,2,3,4 and 5, Local Polynomial (LP) with the power of 1 and 2, Global Polynomial (GP), radial basis functions - spline with tension (SPT), completely regularized spline (CRS), multiquatratic (MTQ), inverse multiquatratic (IMTQ), and thin plate spline (TPS) - and some geostatistical methods as, ordinary kriging (OK), Simple Kriging (SK) and Universal Kriging (UK), used in previous works (Pereira et al., 2014). On average, the soil MS of the studied plot had 686

  18. Seasonal frost effects on the dynamic behavior of a twenty-story office building

    Yang, Z.; Dutta, U.; Xiong, F.; Biswas, N.; Benz, H.

    2008-01-01

    Studies have shown that seasonal frost can significantly affect the seismic behavior of a bridge foundation system in cold regions. However, little information could be found regarding seasonal frost effects on the dynamic behavior of buildings. Based on the analysis of building vibration data recorded by a permanent strong-motion instrumentation system, the objective of this paper is to show that seasonal frost can impact the building dynamic behavior and the magnitude of impact may be different for different structures. Ambient noise and seismic data recorded on a twenty-story steel-frame building have been analyzed to examine the building dynamic characteristics in relationship to the seasonal frost and other variables including ground shaking intensity. Subsequently, Finite Element modeling of the foundation-soil system and the building superstructure was conducted to verify the seasonal frost effects. The Finite Element modeling was later extended to a reinforced-concrete (RC) type building assumed to exist at a similar site as the steel-frame building. Results show that the seasonal frost has great impact on the foundation stiffness in the horizontal direction and a clear influence on the building dynamic behavior. If other conditions remain the same, the effects of seasonal frost on structural dynamic behavior may be much more prominent for RC-type buildings than for steel-frame buildings. ?? 2007 Elsevier B.V. All rights reserved.

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

    HAQ MA

    2009-05-12

    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.

  20. Frost resistance in alpine woody plants.

    Neuner, Gilbert

    2014-01-01

    This report provides a brief review of key findings related to frost resistance in alpine woody plant species, summarizes data on their frost resistance, highlights the importance of freeze avoidance mechanisms, and indicates areas of future research. Freezing temperatures are possible throughout the whole growing period in the alpine life zone. Frost severity, comprised of both intensity and duration, becomes greater with increasing elevation and, there is also a greater probability, that small statured woody plants, may be insulated by snow cover. Several frost survival mechanisms have evolved in woody alpine plants in response to these environmental conditions. Examples of tolerance to extracellular freezing and freeze dehydration, life cycles that allow species to escape frost, and freeze avoidance mechanisms can all be found. Despite their specific adaption to the alpine environment, frost damage can occur in spring, while all alpine woody plants have a low risk of frost damage in winter. Experimental evidence indicates that premature deacclimation in Pinus cembra in the spring, and a limited ability of many species of alpine woody shrubs to rapidly reacclimate when they lose snow cover, resulting in reduced levels of frost resistance in the spring, may be particularly critical under the projected changes in climate. In this review, frost resistance and specific frost survival mechanisms of different organs (leaves, stems, vegetative and reproductive over-wintering buds, flowers, and fruits) and tissues are compared. The seasonal dynamics of frost resistance of leaves of trees, as opposed to woody shrubs, is also discussed. The ability of some tissues and organs to avoid freezing by supercooling, as visualized by high resolution infrared thermography, are also provided. Collectively, the report provides a review of the complex and diverse ways that woody plants survive in the frost dominated environment of the alpine life zone.

  1. A New Method of Observing Delamination Frost heave Amount and Its Applicability in the Seasonal Frozen Area%一种新的分层冻胀量观测方法及其在季节冻土区的应用

    陈继; 张喜发; 王英梅

    2004-01-01

    Observation of delamination frost-heave is of significance in the study of foundation frost damage. The three main methods of observing delamination frost-heave, which are mono-frost-heave-ruler method, multi-frost-heave-ruler method and magnetic-loop method, are briefly introduced in this paper at first. Their respective advantages and disadvantages are analyzed. And then, according to the mechanism of frost-heave and the law of water migration and ice-forming in the freezing soil, a new approximate indirect method of observing the delamination frost-heave, which is antitheses, is brought forward by comparing surface frost-heave and frost-depth. On the basis of observation result in Chengyu Expressway and Daqing, its applicability is analyzed from three aspects under different groundwater level and soil property in seasonal frozen area. The result shows that this method is applicable for these two areas.

  2. Susceptibility of polysiloxane and colloidal silica to degradation by soil microorganisms

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

    1997-11-01

    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.

  3. Frost resistance of building materials

    Hansen, Ernst Jan De Place

    In this thesis it is shown that the critical degree of saturation is suitable as parameter for the frost resistance of porous building materials. A numerical model for prediction of critical degrees of saturation based on fracture mechanics and phase geometry of two-phase materials, e.g. porous...... materials, has been developed.The importance of the pore structure on the development of stresses in the material during freezing is emphasized. To verify the model, experimental investigations are made on various concretes without air-entrainment and brick tiles with different porosities...

  4. The Inharmonious Conflicts in Robert Frost's Poetry

    杨苗

    2015-01-01

    Robert Frost is one of the most distinguished poets,most of his poems are about the inharmonious relationship between nature and men,Conflicts are like a“thread”appearing in his poems.Frost’s true philosophy on men and life contributes to his wisdom and artistic poems.Frost tries to illustrate the conflict between nature and men in philosophy concern.

  5. Frost damage of concrete subject to confinement

    Hasholt, Marianne Tange

    2016-01-01

    When internal frost damage is observed in real concrete structures, the usual pattern is cracks with a preferred orientation parallel to the exposed surface. When exposing concrete with poor frost resistance to a standardised freeze/thaw test in the laboratory, the orientations of the resulting...

  6. Restoring sedges and mosses into frost heaving iron fens, San Juan Mountains, Colorado

    R.A. Chimner

    2011-08-01

    Full Text Available Rare iron fens in the San Juan Mountains of Colorado are frequently in poor condition due to mining, roads and ditches, which have left much of the fen completely bare of vegetation. Natural revegetation is slow to occur in the bare areas because of severe frost heave in the cold mountain climate. Therefore, experimental revegetation plots were conducted in a factorial design with mulching and no mulching, crossed with moss diaspores, sedge transplants, and moss and sedge combined. Mulching influenced surface soil temperatures by reducing the midday highs and increasing the night-time lows, which decreased the frequency and amount of frost heave. Peat moisture also modified frost heave, with the greatest frost heaving occurring near 75 % peat moisture content (water table 10–20 cm below the surface and the least when soils were either wetter or drier. Moss survival was dependent on mulch, with no moss surviving in plots without mulch. Mulching also increased sedge transplant survival. In summary, mulching significantly increased the success of vegetation restoration efforts for frost heave areas in mountain fens.

  7. Land use and Hydrological Characteristics of Volcanic Urban Soils for Flood Susceptibility Modeling, Ciudad de Colima (Mexico)

    Perez Gonzalez, M. L.; Capra, L.; Borselli, L.; Ortiz, A.

    2015-12-01

    The fast population rate growth and the unplanned urban development has created an increase of urban floods in the City of Colima. Land use change has transformed the hydrological behavior of the watersheds that participates on the runoff-infiltration processes that governs the pluvial concentrations. After the urban areas enlargement, 13% from 2010 to 2015, rainfall has caused significant damages to the downtown community. Therefore it is important to define the main hydraulic properties of the soils surrounding the city. The soil of the region is derived from the debris avalanche deposits of the Volcano of Colima. The volcanic soil cover is only 10 to 15 cm depth. To test the soils of the region, sampling locations were chosen after making a land use map from a Landsat image. The map was done by selecting and dividing similar surface images patterns into three main classifications: Natural (N1), Agricultural (N5) and Urban (N4) surfaces. Thirty-Three soil samples were collected and grouped in nine out of ten land use subdivisions. The 10thsubdivision, represents the completed urbanized area. The land use model is made using spot 4 1A images from the year 2010 up to year 2015. This land use evolutionary analysis will be a base to evaluate the change of the runoff-infiltration rate, direction, and concentration areas for the future flood susceptibility model. To get the parameters above, several soil analysis were performed. The results were that all the soil samples tested were classified as sandy soils. The water content values were from 7% (N4) to 45% (N1) while bulk density values for the same sample were form 0.65 (N1) to 1.50 (N4) g/cm3. The particle density and the porosity values were from 1.65 g/cm3 /5.5% (N4) - 2.65 g/cm3/ 75.40% (N1). The organic matter content was around 0.1% for urban soils and up to 6% on natural and agricultural soils. Some other test like electric conductivity and pH were performed. The obtained parameters were used to get other

  8. Impacts of geology and land use on magnetic susceptibility and selected heavy metals in surface soils of Mashhad plain, northeastern Iran

    Karimi, Alireza; Haghnia, Gholam Hosain; Ayoubi, Shamsollah; Safari, Tayebeh

    2017-03-01

    Magnetic susceptibility is a fast, inexpensive and reliable technique for estimating and monitoring the anthropogenic contamination of soil with heavy metals. However, it is essential to determine the factors affecting magnetic susceptibility before applying this technique to environmental studies. The objectives of this study were to investigate i) the effect of parent materials and land use on the magnetic susceptibility and concentrations of Fe, Ni, Pb and Zn, and ii) capability of magnetic susceptibility as an indicator of anthropogenic heavy metals contamination of soil in Mashhad plain, northeastern Iran. One hundred seventy-eight composite surface soil samples (0-10 cm) were taken. The aqua-regia extractable concentrations of Fe, Ni, Zn and Pb were determined by atomic absorption spectroscopy. Magnetic susceptibility at low and high frequency (χlf and χhf) were measured and frequency dependent susceptibility (χfd) was calculated. The average concentrations of Fe, Ni, Pb and Zn were 22,812, 61.4, 74.1 and 31.6 mg kg- 1, respectively. The highest contents of Pb (69.1 mg kg- 1) and Zn (149 mg kg- 1) were observed in urban area. The highest concentration of Ni was 41,538 mg kg- 1 observed in the soils developed from ultramafic rocks. Magnetic susceptibility varied from 20.3 on marly sediments to 311.8 × 10- 8 m3 kg- 1 on ultramafic rocks. A positive strong correlation (Pvalue < 0.01, r = 0.88) was obtained between Ni and χlf. There were no significant relationships between Zn and Pb with χlf, therefore it seems that magnetic susceptibility has not been affected significantly by anthropogenic activities which enhanced Pb and Zn concentrations in urban soils. The results indicated that magnetic susceptibility was mainly controlled by Ni containing minerals with lithogenic origin. Therefore, in the soils studied, magnetic susceptibility could not be employed as indicator of anthropogenic contamination of soil with heavy metals.

  9. A Comparative Study of Whitman and Frost

    田寨耕

    2014-01-01

    Walt Whitman and Robert Frost are both famous poets in American literary history. They share a great deal in common. This paper attempts to make a study of the two poets by means of comparing their similarities and differences.

  10. Assessing frost damages using dynamic models in walnut trees: exposure rather than vulnerability controls frost risks.

    Charrier, Guillaume; Chuine, Isabelle; Bonhomme, Marc; Améglio, Thierry

    2017-02-09

    Frost damages develop when exposure overtakes frost vulnerability. Frost risk assessment therefore needs dynamic simulation of frost hardiness using temperature and photoperiod in interaction with developmental stage. Two models, including or not the effect of photoperiod were calibrated using five years of frost hardiness monitoring (2007-2012), in two locations (low and high elevation) for three walnut genotypes with contrasted phenology and maximum hardiness (Juglans regia cv Franquette, Juglans regia x nigra 'Early' and 'Late'). The Photothermal model predicted more accurate values for all genotypes (Efficiency = 0.879; RMSEP = 2.55 °C) than the Thermal model (Efficiency = 0.801; RMSEP = 3.24 °C). Predicted frost damages were strongly correlated to minimum temperature of the freezing events (ρ = -0.983) rather than actual frost hardiness (ρ = -0.515), or ratio of phenological stage completion (ρ = 0.336). Higher frost risks are consequently predicted during winter, at high elevation, whereas spring is only risky at low elevation in early genotypes exhibiting faster dehardening rate. However, early frost damages, although of lower value, may negatively affect fruit production the subsequent year (R(2)  = 0.381, P = 0.057). These results highlight the interacting pattern between frost exposure and vulnerability at different scales and the necessity of intra-organ studies to understand the time course of frost vulnerability in flower buds along the winter.

  11. Mercury in mercury(II)-spiked soils is highly susceptible to plant bioaccumulation.

    Hlodák, Michal; Urík, Martin; Matúš, Peter; Kořenková, Lucia

    2016-01-01

    Heavy metal phytotoxicity assessments usually use soluble metal compounds in spiked soils to evaluate metal bioaccumulation, growth inhibition and adverse effects on physiological parameters. However, exampling mercury phytotoxicity for barley (Hordeum vulgare) this paper highlights unsuitability of this experimental approach. Mercury(II) in spiked soils is extremely bioavailable, and there experimentally determined bioaccumulation is significantly higher compared to reported mercury bioaccumulation efficiency from soils collected from mercury-polluted areas. Our results indicate this is not affected by soil sorption capacity, thus soil ageing and formation of more stable mercuric complexes with soil fractions is necessary for reasonable metal phytotoxicity assessments.

  12. Liquefaction Susceptibility of Soils With Clay Particles from Earthquake-induced Landslides

    CHEN Chuan-sheng; JIANG Xin; ZHANG Xu

    2007-01-01

    The main reason for earthquake-induced landslides is liquefaction of soil, a process considered to occur mostly in sandy soils. Liquefaction can occur in clayey soils has also been reported and proven in the recent literature, but liquefaction in clayey soils still remains unclear and there are many questions that need to be addressed. In order to address these questions, an depth study on the liquefaction potential of clayey soils was conducted on the basis of field investigation and a series of laboratory tests on the samples collected from the sliding surface of the landslides. The liquefaction potential of the soils was studied by means of undrained cyclic ring-shear tests. Research results show that the liquefaction potential of sandy soils is higher than that of clayey soils given the same void ratio;the soil resistance to liquefaction rises with an increase in plasticity for clayey soils; relation between plasticity index and the liquefaction potential of soil can be used in practical application to estimate the liquefaction potential of soil.

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

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

    2012-01-01

    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 th

  14. Using magnetic susceptibility to facilitate more rapid, reproducible and precise delineation of hydric soils in the midwestern USA

    Grimley, D.A.; Arruda, N.K.; Bramstedt, M.W.

    2004-01-01

    Standard field indicators, currently used for hydric soil delineations [USDA-NRCS, 1998. Field indicators of hydric soils in the United States, Version 4.0. In: G.W. Hurt et al. (Ed.), United States Department of Agriculture-NRCS, Fort Worth, TX], are useful, but in some cases, they can be subjective, difficult to recognize, or time consuming to assess. Magnetic susceptibility (MS) measurements, acquired rapidly in the field with a portable meter, have great potential to help soil scientists delineate and map areas of hydric soils more precisely and objectively. At five sites in Illinois (from 5 to 15 ha in area) with contrasting soil types and glacial histories, the MS values of surface soils were measured along transects, and afterwards mapped and contoured. The MS values were found to be consistently higher in well-drained soils and lower in hydric soils, reflecting anaerobic deterioration of both detrital magnetite and soil-formed ferrimagnetics. At each site, volumetric MS values were statistically compared to field indicators to determine a critical MS value for hydric soil delineation. Such critical values range between 22??10-5 and 33??10-5 SI in silty loessal or alluvial soils in Illinois, but are as high as 61??10-5 SI at a site with fine sandy soil. A higher magnetite content and slower dissolution rate in sandy soils may explain the difference. Among sites with silty parent material, the lowest critical value (22??10-5 SI) occurs in soil with low pH (4.5-5.5) since acidic conditions are less favorable to ferrimagnetic mineral neoformation and enhance magnetite dissolution. Because of their sensitivity to parent material properties and soil pH, critical MS values must be determined on a site specific basis. The MS of studied soil samples (0-5 cm depth) is mainly controlled by neoformed ultrafine ferrimagnetics and detrital magnetite concentrations, with a minor contribution from anthropogenic fly ash. Neoformed ferrimagnetics are present in all samples

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

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

    2013-12-01

    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

  16. Latest results from FROST at Jefferson Lab

    Ritchie B.G.

    2014-06-01

    Full Text Available The spectrum of broad and overlapping nucleon excitations can be greatly clarified by use of a polarized photon beam incident on a polarized target in meson photoproduction experiments. At Jefferson Lab, a program of such measurements has made use of the Jefferson Lab FROzen Spin Target (FROST. An overview of preliminary results are presented.

  17. Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands.

    Jassey, Vincent E J; Lamentowicz, Mariusz; Bragazza, Luca; Hofsommer, Maaike L; Mills, Robert T E; Buttler, Alexandre; Signarbieux, Constant; Robroek, Bjorn J M

    2016-09-01

    Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions due to osmotic stress, and changing temperature regimes. Using four European peatlands reflecting different frequencies of frost events, we show that peatland testate amoeba communities diverge among sites with different winter climates, and that this is reflected through contrasting functions. We found that exposure to harder soil frost promoted species β-diversity (species turnover) thus shifting the community composition of testate amoebae. In particular, we found that harder soil frost, and lower water-soluble phenolic compounds, induced functional turnover through the decrease of large species (-68%, >80μm) and the increase of small-bodied mixotrophic species (i.e. Archerella flavum; +79%). These results suggest that increased exposure to soil frost could be highly limiting for large species while smaller species are more resistant. Furthermore, we found that β-glucosidase enzymatic activity, in addition to soil temperature, strongly depended of the functional diversity of testate amoebae (R(2)=0.95, ANOVA). Changing winter conditions can therefore strongly impact peatland decomposition process, though it remains unclear if these changes are carried-over to the growing season.

  18. Soybean susceptibility to manufactured nanomaterials with evidence for food quality and soil fertility interruption.

    Priester, John H; Ge, Yuan; Mielke, Randall E; Horst, Allison M; Moritz, Shelly Cole; Espinosa, Katherine; Gelb, Jeff; Walker, Sharon L; Nisbet, Roger M; An, Youn-Joo; Schimel, Joshua P; Palmer, Reid G; Hernandez-Viezcas, Jose A; Zhao, Lijuan; Gardea-Torresdey, Jorge L; Holden, Patricia A

    2012-09-11

    Based on previously published hydroponic plant, planktonic bacterial, and soil microbial community research, manufactured nanomaterial (MNM) environmental buildup could profoundly alter soil-based food crop quality and yield. However, thus far, no single study has at once examined the full implications, as no studies have involved growing plants to full maturity in MNM-contaminated field soil. We have done so for soybean, a major global commodity crop, using farm soil amended with two high-production metal oxide MNMs (nano-CeO(2) and -ZnO). The results provide a clear, but unfortunate, view of what could arise over the long term: (i) for nano-ZnO, component metal was taken up and distributed throughout edible plant tissues; (ii) for nano-CeO(2), plant growth and yield diminished, but also (iii) nitrogen fixation--a major ecosystem service of leguminous crops--was shut down at high nano-CeO(2) concentration. Juxtaposed against widespread land application of wastewater treatment biosolids to food crops, these findings forewarn of agriculturally associated human and environmental risks from the accelerating use of MNMs.

  19. Air void structure and frost resistance

    Hasholt, Marianne Tange

    2014-01-01

    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...... 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....

  20. Frost-proof heat recovery; Frostsikker varmegjenvinning

    Groenbaek, Henning; Jenssen, Henning Bent

    2011-07-01

    Technical regulations (TEK10) sets high standards for temperature efficiency of ventilation systems. Heat recovery equipment should be selected from the risk of leakage. Rotating heat exchanger has normally no problem with icing before the temperature approaches -20 C. For the countercurrent heat exchanger bypass-icing is the best method of frost resistant heat exchanger. In addition to selecting the best frost protection method, it is also important how to monitor the formation of ice in the exchanger. The best way is to measure the pressure drop over the heat exchanger. Bypass deicing requires that the unit is designed so that outside air can be led outside heat exchanger and directly to the heater. (AG)

  1. Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L.) stand in south-eastern Germany based on repeated digital photographs

    Menzel, Annette; Helm, Raimund; Zang, Christian

    2015-04-01

    change points of the model almost perfectly matched the expected break points: i) start of the first greening between DOY (day of the year) 108 to 119 (mean 113), ii) end of greening and iii) visible frost damage after the frost on the night of May 3rd/4th (DOY 123/124), iv) re-sprouting 19 to 38 days after the frost, and v) full maturity around DOY 178 (166 to 184) when all beech crowns had fully recovered. Since frost damage was nearly 100%, individual susceptibility did not depend on the timing of first spring leaf unfolding. However, we could identify significant patterns in fitness linked to an earlier start of leaf unfolding.

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

    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

    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)

  3. How endangered is sexual reproduction of high-mountain plants by summer frosts? Frost resistance, frequency of frost events and risk assessment.

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

    2013-03-01

    In temperate-zone mountains, summer frosts usually occur during unpredictable cold spells with snow-falls. Earlier studies have shown that vegetative aboveground organs of most high-mountain plants tolerate extracellular ice in the active state. However, little is known about the impact of frost on reproductive development and reproductive success. In common plant species from the European Alps (Cerastium uniflorum, Loiseleuria procumbens, Ranunculus glacialis, Rhododendron ferrugineum, Saxifraga bryoides, S. moschata, S. caesia), differing in growth form, altitudinal distribution and phenology, frost resistance of reproductive and vegetative shoots was assessed in different reproductive stages. Intact plants were exposed to simulated night frosts between -2 and -14 °C in temperature-controlled freezers. Nucleation temperatures, freezing damage and subsequent reproductive success (fruit and seed set, seed germination) were determined. During all reproductive stages, reproductive shoots were significantly less frost resistant than vegetative shoots (mean difference for LT50 -4.2 ± 2.7 K). In most species, reproductive shoots were ice tolerant before bolting and during fruiting (mean LT50 -7 and -5.7 °C), but were ice sensitive during bolting and anthesis (mean LT50 around -4 °C). Only R. glacialis remained ice tolerant during all reproductive stages. Frost injury in reproductive shoots usually led to full fruit loss. Reproductive success of frost-treated but undamaged shoots did not differ significantly from control values. Assessing the frost damage risk on the basis of summer frost frequency and frost resistance shows that, in the alpine zone, low-statured species are rarely endangered as long as they are protected by snow. The situation is different in the subnival and nival zone, where frost-sensitive reproductive shoots may become frost damaged even when covered by snow. Unprotected individuals are at high risk of suffering from frost damage, particularly

  4. Time as An Important Soil-Forming Factor Influencing Modern and Ancient Magnetic Susceptibility Enhancement Along the Delaware River Valley, USA

    Stinchcomb, G. E.; Peppe, D. J.; Driese, S. G.

    2011-12-01

    Magnetic susceptibility is an increasingly popular low-cost method for rapidly assessing paleoclimate and paleoenvironmental impact on buried soils. The goal of this study is to determine the primary influence(s) on soil magnetic susceptibility along floodplain, terrace and upland soils in the middle Delaware River Valley, USA, using environmental magnetic, pedologic, and stratigraphic techniques. Two-hundred thirty samples were collected from age-constrained sandy, quartz-rich, floodplain, terrace, and upland soils (Entisols, Inceptisols). A Kruskal-Wallis (K-W) and post-hoc Tukey-Kramer (T-K) (α=0.05) multiple comparisons analysis on 176 mass-specific low-field susceptibility (Xlf) assays show that A and B horizons are magnetically enhanced compared to C and E horizons (p<0.0001). Results of descriptive soil micromorphology show that A and B horizons contain anywhere from 10-50% more amorphous organic matter and clay films along pores than do C and E horizons. Enhanced Xlf values also correlate positively (R^2=0.63) with the soil molecular weathering ratio of Alumina/Bases, suggesting that increased weathering likely results in the formation of pedogenic magnetic minerals and enhanced magnetic susceptibility signal. Additional K-W and T-K testing show that Xlf results, when grouped by floodplain-terrace designation (i.e., chronofunction) are significantly different (p<0.0001). The older T3 terrace and upland Xlf values (0.34±0.14 10^-6 m^3 kg^-1) are greater than the younger T2 terrace (0.18±0.06 10^-6 m^3 kg^-1) values, which are greater than modern floodplain (0.09±0.01 10^-6 m^3 kg^-1) Xlf values. These data suggest that longer intervals of soil formation enhance the Χlf value. This hypothesis is further supported when 159 Xlf values are plotted vs. age for the entire Holocene. A locally-weighted regression smoothing curve (LOESS) shows two distinct intervals of magnetic enhancement during previously established dry intervals, the early and late

  5. Evaluation and refinement of sprinkler application rate models used in frost protection

    Perry, K.B.

    1979-01-01

    Two models of the sprinkled orchard which predict the application rates required for successful frost protection were evaluated. A Sprinkling Application Rate (SPAR79) model, used the heat budget approach to determine the rate of heat lost by the plant part through radiative, convective, and latent heat transfer processes at the actual plant part temperature and at the plant part's critical temperature. The difference between these two rates of heat loss is the rate at which heat must be added by the latent heat of fusion liberated as the applied water freezes. This model added consideration of humidity and ice accumulation to a refinement of the heat budget configuration of earlier models. It showed that humidity is not a contributing factor in the determination of application rates. Ice accumulation was shown to decrease the required application rate by 67% when it increased the characteristic plant part size from 0.2 to 2.0 cm. A distribution factor, a component of a factor previously only estimated, was shown to increase by 30% (from 1.0 to 1.3) as blossom and leaf development progressed. Pulsed sprinkling for frost protection was carried out during six frost nights. Blossom temperatures, application rate, pulsing cycle, wind speed and air temperature were simultaneously recorded. These observations illustrated that in order to provide adequate protection an appropriate application rate and pulsing cycle must be provided by the model. It was concluded that by varying the distribution factor through the growing season and varying the application rate through a single frost night by pulsing, according to atmospheric parameters and ice accumulation, a significant decrease in amount of water applied may be realized. This decrease in water applied will alleviate ice buildup, water cost, soil drainage and nutrient leaching problems associated with sprinkling for frost protection.

  6. Robert Frost and his Poem The Way not Taken

    张晓珊

    2006-01-01

    Robert Frost is one of the most celebrated poets in America as well in the world. This article mainly concerned about his life, the subject matter of Frost' s poems and his writing style. Particularly, the article makes a detailed analysis of his poem "the road not taken which is the typical of the poet' s style and relate the poem with the whole life of Frost.

  7. 冻胀过程与冻结缘特性%Process of Frost Heave and Characteristics of Frozen Fringe

    何平; 邴慧; 张钊; 杨成松

    2004-01-01

    The complex process of soil freezing which relates to moisture field, temperature and stress field usually accompanies water migration and crystallization. The mechanism of water migration in the -frozen fringe is blurry though there have rather mature theory analyzing water migration in the unfrozen zone and fully-frozen zone. It is a visualized and easy method to calculate the potential gradient of frozen fringe by frost heave amount, the duration of the steady state of frost heaving and the coefficient of permeability based on the Darcy penetration theory, not directly considering water driving force, ice segregation temperature and the thickness of frozen fringe. The method is feasible by comparing the calculated amount of frost-heaving with the test data.

  8. Mechanisms discussion of frost heave and test verifications of moisture migration

    Chang Yuan; ChengSong Yang; LianHai Zhang

    2014-01-01

    Herein we review research on the structure of the frozen fringe and one of its key characteristics (unfrozen water content), and compare its current measurement methods, including pulsed nuclear magnetic resonance (NMR), time-domain re-flectometry (TDR), calorimetry, thermometry, the sublimation method, and CT imagery. A freeze-thaw cycle experiment with remolded soil was conducted inside to verify the mechanism of frost heave, measuring such variables as soil-water potential, temperature, water supplement, and the position of the freezing front. Conclusions from the analysis of the experiment data are:(1) The soil-water potential, the water supplement, and the position of the freezing front vary with temperature;and (2) the temperature gradient induces the soil-water potential, which in turn provides a stable driving force for moisture migration.

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

    Pedro H. Weirich Neto

    2002-01-01

    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

  10. Delayed frost growth on jumping-drop superhydrophobic surfaces.

    Boreyko, Jonathan B; Collier, C Patrick

    2013-02-26

    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 interdrop frost wave. The growth of this interdrop frost front is shown to be up to 3 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 interdrop 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 interdrop phenomenon that is strongly coupled to the wettability and drop size distribution of the surface. A jumping-drop superhydrophobic condenser minimized frost formation relative to a conventional dropwise condenser in two respects: preventing heterogeneous ice nucleation by continuously removing subcooled condensate, and delaying frost growth by limiting the success of interdrop ice bridge formation.

  11. Frost monitoring of fruit tree with satellite data

    Fan, Jinlong; Zhang, Mingwei; Cao, Guangzheng; Zhang, Xiaoyu; Liu, Chenchen; Niu, Xinzan; Xu, Wengbo

    2012-09-01

    The orchards are developing very fast in the northern China in recent years with the increasing demands on fruits in China. In most parts of the northern China, the risk of frost damage to fruit tree in early spring is potentially high under the background of global warming. The growing season comes earlier than it does in normal year due to the warm weather in earlier spring and the risk will be higher in this case. According to the reports, frost event in spring happens almost every year in Ningxia Region, China. In bad cases, late frosts in spring can be devastating all fruit. So lots of attention has been given to the study in monitoring, evaluating, preventing and mitigating frost. Two orchards in Ningxia, Taole and Jiaozishan orchards were selected as the study areas. MODIS data were used to monitor frost events in combination with minimum air temperature recorded at weather station. The paper presents the findings. The very good correlation was found between MODIS LST and minimum air temperature in Ningxia. Light, middle and severe frosts were captured in the study area by MODIS LST. The MODIS LST shows the spatial differences of temperature in the orchards. 10 frost events in April from 2000 to 2010 were captured by the satellite data. The monitoring information may be hours ahead circulated to the fruit farmers to prevent the damage and loss of fruit trees.

  12. Frost related dieback in Estonian energy plantations of willows in relation to fertilisation and pathogenic bacteria

    Cambours, M.A.; Nejad, P. [Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, 750 07 Uppsala (Sweden); Heinsoo, K. [Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu (Estonia); Granhall, U. [Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025, 750 07 Uppsala (Sweden)

    2006-03-15

    Two 9-year old Estonian Salix plantations suffering from dieback were studied: one situated on poor mineral soil and divided into fertilised and unfertilised plots (Saare plantation) and another growing on a well-decomposed and nitrogen-rich organic soil, without fertiliser application (Kambja plantation). Bacteria from internal tissues of visually damaged shoots from seven clones were isolated in spring and autumn. The strains were subsequently biochemically characterised and tested for ice nucleation activity and pathogenicity on Salix. Some strains were also analysed with 16S rRNA. High numbers of culturable bacteria were found, belonging mainly to Erwinia, Sphingomonas, Pseudomonas and Xanthomonas spp. Fertilised plots were significantly more colonised by bacteria than unfertilised plots and also more extensively damaged, showing a lower density of living plants after 7 years of culture. More ice nucleation active (INA) strains were found in Saare fertilised plots and at Kambja than in Saare unfertilised plots. Likewise, most pathogenic strains were isolated from Saare fertilised plots and from Kambja. For some of the willow clones studied, dieback appeared to be related to both clonal frost sensitivity and abundance of INA and pathogenic bacteria. The plantations probably suffered from the presence of high amounts of pathogens and from frost related injuries aggravated by INA bacteria. Most probably the fertilisation at Saare and the nitrogen-rich soil at Kambja created a favourable environment for bacterial development and led to high dieback levels after the first harvest. (author)

  13. Frost-protected shallow foundation: work in seasonally-freezing through grounds, practice of thermal calculation (rus

    Belyakov V.A.

    2011-12-01

    Full Text Available The object of research is frost-protected shallow foundations.The article focuses on a technique of solving the nonstationary and nonlinear problem of freezing/thawing of soil in a 2D target setting, using software based on the finite-element method. The COSMOS/M package from Structural Research & Analysis Corp. is used as an example. The article also mentions some peculiarities of data input, caused by the non-linearity and nonstationarity of the problem.

  14. Landslide susceptibility mapping using downscaled AMSR-E soil moisture: A case study from Cleveland Corral, California, US

    As soil moisture increases, slope stability decreases. Remotely sensed soil moisture data can provide routine updates of slope conditions necessary for landslide predictions. For regional scale landslide investigations, only remote sensing methods have the spatial and temporal resolution required to...

  15. Modelling of frost formation and growth on microstuctured surface

    Muntaha, Md. Ali; Haider, Md. Mushfique; Rahman, Md. Ashiqur

    2016-07-01

    Frost formation on heat exchangers is an undesirable phenomenon often encountered in different applications where the cold surface with a temperature below freezing point of water is exposed to humid air. The formation of frost on the heat transfer surface results in an increase in pressure drop and reduction in heat transfer, resulting in a reduction of the system efficiency. Many factors, including the temperature and moisture content of air, cold plate temperature, surface wettability etc., are known to affect frost formation and growth. In our present study, a model for frost growth on rectangular, periodic microgroove surfaces for a range of microgroove dimension (ten to hundreds of micron) is presented. The mathematical model is developed analytically by solving the governing heat and mass transfer equations with appropriate boundary conditions using the EES (Engineering Equation Solver) software. For temperature, a convective boundary condition at frost-air interface and a fixed cold plate surface temperature is used. Instead of considering the saturation or super-saturation models, density gradient at the surface is obtained by considering experimentally-found specified heat flux. The effect of surface wettability is incorporated by considering the distribution of condensed water droplets at the early stage of frost formation. Thickness, density and thermal conductivity of frost layer on the micro-grooved surfaces are found to vary with the dimension of the grooves. The variation of density and thickness of the frost layer on these micro-grooved surfaces under natural convection is numerally determined for a range of plate temperature and air temperature conditions and is compared with experimental results found in the open literature.

  16. Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces

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

    2013-01-01

    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.

  17. Bioinspired Antifreeze Secreting Frost-Responsive Pagophobic Coatings

    Sun, Xiaoda; Damle, Viraj; Rykaczewski, Konrad

    2014-11-01

    Prevention of ice and frost accumulation is of interest to transportation, power generation, and agriculture industries. Superhydrophobic and lubricant impregnated pagophobic coatings have been proposed, however, they both fail in frosting conditions. Inspired by functional liquid secretion in natural systems, such as toxin secretion by poison dart frost in response to predator presence, we developed frost-responsive antifreeze secreting pagophobic coatings. These are bi-layered coatings with an inner superhydrophilic ``dermis'' infused with antifreeze and an outer permeable superhydrophobic ``epidermis.'' The superhydrophobic epidermis separates the antifreeze from the environment and prevents ice accumulation by repelling impinging water droplets. In frosting conditions, the antifreeze is secreted from the dermis through pores in the epidermis either due to contact with condensed droplets or temporary switch of the epidermis wettability from hydrophobic to hydrophilic caused by surface icing. Here we demonstrate superior performance of this multifunctional coating in simulated frosting, freezing mist/fog, and freezing spray/rain conditions. KR acknowledges startup funding from ASU.

  18. Fractal model for simulation of frost formation and growth

    2010-01-01

    A planar fractal model for simulation of frost formation and growth was proposed based on diffusion limited aggregation(DLA)model and the computational simulation was carried out in this paper.By changing the times of program running circulation and the ratio of random particles generated,the simulation figures were gained under different conditions.A microscope is used to observe the shape and structure of frost layer and a digital camera with high resolution is used to record the pattern of frost layer at different time.Through comparing the simulation figures with the experimental images,we find that the simulation results agree well with the experimental images in shape and the fractal dimension of simulation figures is nearly equal to that of experimental images.The results indicate that it is reasonable to represent frost layer growth time with the program circulation times and to simulate the frost layer density variation during its growth process by reducing the random particle generation probability.The feasibility of using the suggested model to simulate the process of frost formation and growth was justified.The insufficiencies and its causes of this fractal model are also discussed.

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

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

    2012-04-01

    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.

  20. Geochemical association of Pu and Am in selected host-phases of contaminated soils from the UK and their susceptibility to chemical and microbiological leaching.

    Kimber, Richard L; Corkhill, Claire L; Amos, Sean; Livens, Francis R; Lloyd, Jonathan R

    2015-04-01

    Understanding the biogeochemical behaviour and potential mobility of actinides in soils and groundwater is vital for developing remediation and management strategies for radionuclide-contaminated land. Pu is known to have a high Kd in soils and sediments, however remobilization of low concentrations of Pu remains a concern. Here, some of the physicochemical properties of Pu and the co-contaminant, Am, are investigated in contaminated soils from Aldermaston, Berkshire, UK, and the Esk Estuary, Cumbria, UK, to determine their potential mobility. Sequential extraction techniques were used to examine the host-phases of the actinides in these soils and their susceptibility to microbiological leaching was investigated using acidophilic sulphur-oxidising bacteria. Sequential extractions found the majority of (239,240)Pu associated with the highly refractory residual phase in both the Aldermaston (63.8-85.5 %) and Esk Estuary (91.9-94.5%) soils. The (241)Am was distributed across multiple phases including the reducible oxide (26.1-40.0%), organic (45.6-63.6%) and residual fractions (1.9-11.1%). Plutonium proved largely resistant to leaching from microbially-produced sulphuric acid, with a maximum 0.18% leached into solution, although up to 12.5% of the (241)Am was leached under the same conditions. If Pu was present as distinct oxide particles in the soil, then (241)Am, a decay product of Pu, would be expected to be physically retained in the particle. The differences in geochemical association and bioleachability of the two actinides suggest that this is not the case and hence, that significant Pu is not present as distinct particles. These data suggest the majority of Pu in the contaminated soils studied is highly recalcitrant to geochemical changes and is likely to remain immobile over significant time periods, even when challenged with aggressive "bioleaching" bacteria.

  1. Outreach program by measurements of frost depth in Japan

    Harada, K.; Yoshikawa, K.; Iwahana, G.; Stanilovskaya, J. V.; Sawada, Y.

    2015-12-01

    In order to emphasis their interest for earth sciences, an outreach program through measurements of frost depth is conducting in Japan since 2011. This program is made at elementary, junior high and high schools in Hokkaido, northern part of Japan where seasonal ground freezing occurs in winter. At schools, a lecture was made and a frost tube was set at schoolyard, as the same tube and protocol as UAF's Permafrost Outreach Program, using clear tube with blue-colored water. Frost depth was measured directly once a week at each school by students during ground freezing under no snow-removal condition. In 2011 season, we started this program at three schools, and the number of participated school is extended to 29 schools in 2014 winter season, 23 elementary schools, 5 junior high schools and one high school. We visited schools summer time and just before frost season to talk about the method of measurement. After the end of measured period, we also visited schools to explain measured results by each school and the other schools in Japan, Alaska, Canada and Russia. The measured values of frost depth in Hokkaido were ranged between 0cm and more than 50cm. We found that the frost depth depends on air temperature and snow depth. We discussed with student why the frost depth ranged widely and explained the effect of snow by using the example of igloo. In order to validate the effect of snow and to compare frost depths, we tried to measure frost depths under snow-removal and no snow-removal conditions at one elementary school. At the end of December, depths had no significant difference between these conditions, 11cm and 10cm, and the difference went to 14cm, 27cm and 13cm after one month, with about 30cm of snow depth. After these measurements and lectures, students noticed snow has a role as insulator and affects the frost depth. The network of this program will be expected to expand, finally more than a hundred schools.

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

    Cambours, M.A.

    2004-07-01

    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.

  3. A Study on Monitoring Frost of Main Crop in the Area of Ningxia by Using Remote Sensing%宁夏主要作物霜冻遥感监测研究

    张晓煜; 陈豫英; 苏占胜; 周慧琴; 马玉平

    2001-01-01

    The frost occurred is lies on many factors, such as condition ofweather, landform, soil texture, bacterial population and vegetation itself etc. To monitor the frost by using remote sensing, we have to solve many problems, for example, the precision of temperature retrieval and distribution of vegetation by using NOAA data. In addition, we have to consider to both the aerosol and humidity effect on the temperature retrieval. Due to above mentioned reasons, monitoring the frost by remote sensing is rather complicated and difficult. Based on the analysis of the characteristic and the law of the frost, using the data of NOAA and weather station during 1991 to 2000,as well as using the data of the frost damage, there are three methods were introduced to monitor the frost in Ningxia in this paper. The first is difference vegetation index (DVI) which monitoring the frost by means of the difference of vegetation index between fore-frost and after-frost. The second is temperature reference (TR) which monitoring the frost by compare to the difference between the temperature retrieval and frost index of crops. The third is the area of cold valley (ACV) which obtained ACV by integral the temperature below the frost index. We have examined the monitoring precision of those methods, the results show that each is available to monitor the different type of frost in Ningxia.%利用1991~2000年NOAA卫星资料、宁夏各台站温度资料和霜冻调查资料,在分析宁夏霜冻发生规律和特点的基础上,利用植被指数差值(DVI)法(间接法)、温度指示(TR)法(直接法)和冷谷面积法(ACV)监测宁夏不同类型的霜冻,取得了良好效果。

  4. A model for nocturnal frost formation on a wing section: Aircraft takeoff performance penalties

    Dietenberger, M. A.

    1983-01-01

    The nocturnal frost formation on a wing section, to explain the hazard associated with frost during takeoff was investigated. A model of nocturnal frost formation on a wing section which predicts when the nocturnal frost will form and also its thickness and density as a function of time was developed. The aerodynamic penalities as related to the nocturnal frost formation properties were analyzed to determine how much the takeoff performance would be degraded by a specific frost layer. With an aircraft takeoff assuming equations representing a steady climbing flight, it is determined that a reduction in the maximum gross weight or a partial frost clearance and a reduction in the takeoff angle of attack is needed to neutralize drag and life penalities which are due to frost. Atmospheric conditions which produce the most hazardous frost buildup are determined.

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

    Kandula, Max

    2010-01-01

    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.

  6. Experimental investigation of the influence of electric field on frost layer growth under natural convection condition

    2006-01-01

    The influence of direct current (DC) electric field on the thickness and mass of frost on a cold vertical plate was investigated. The photos of frost layer growth were taken with and without the presence of electric field, and results showed that the electric field has a strong influence on the frost thickness. The influences of cold plate temperature and ambient temperature on frost thickness and frost mass were also investigated under the natural convection condition with electric field. Experimental results demonstrated that the cold plate temperature has very strong effect on the frost layer thickness, but its influence on frost mass is minor; the influence of ambient temperature on the frost mass is more obvious than that on the frost thickness.

  7. Forecast of Frost Days Based on Monthly Temperatures

    Castellanos, M. T.; Tarquis, A. M.; Morató, M. C.; Saa-Requejo, A.

    2009-04-01

    Although frost can cause considerable crop damage and mitigation practices against forecasted frost exist, frost forecasting technologies have not changed for many years. The paper reports a new method to forecast the monthly number of frost days (FD) for several meteorological stations at Community of Madrid (Spain) based on successive application of two models. The first one is a stochastic model, autoregressive integrated moving average (ARIMA), that forecasts monthly minimum absolute temperature (tmin) and monthly average of minimum temperature (tminav) following Box-Jenkins methodology. The second model relates these monthly temperatures to minimum daily temperature distribution during one month. Three ARIMA models were identified for the time series analyzed with a stational period correspondent to one year. They present the same stational behavior (moving average differenced model) and different non-stational part: autoregressive model (Model 1), moving average differenced model (Model 2) and autoregressive and moving average model (Model 3). At the same time, the results point out that minimum daily temperature (tdmin), for the meteorological stations studied, followed a normal distribution each month with a very similar standard deviation through years. This standard deviation obtained for each station and each month could be used as a risk index for cold months. The application of Model 1 to predict minimum monthly temperatures showed the best FD forecast. This procedure provides a tool for crop managers and crop insurance companies to asses the risk of frost frequency and intensity, so that they can take steps to mitigate against frost damage and estimated the damage that frost would cost. This research was supported by Comunidad de Madrid Research Project 076/92. The cooperation of the Spanish National Meteorological Institute and the Spanish Ministerio de Agricultura, Pesca y Alimentation (MAPA) is gratefully acknowledged.

  8. General frost growth mechanism on solid substrates with different stiffness.

    Petit, Julien; Bonaccurso, Elmar

    2014-02-01

    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.

  9. Time-domain Response of a Metal Detector to a Target Buried in Soil with Frequency-dependent Magnetic Susceptibility

    2016-07-06

    performance of induction metal detectors widely used in humanitarian demining. This paper studies the specific case of the time-domain response of a small...known to adversely affect the performance of metal detectors . The included analysis and computations extend previous work which has been done mostly in...target in soil based on the presented results. However, computational results complemented with experimental data extend the understanding of the effect that soil has on metal detectors .

  10. Frost Formation: Optimizing solutions under a finite volume approach

    Bartrons, E.; Perez-Segarra, C. D.; Oliet, C.

    2016-09-01

    A three-dimensional transient formulation of the frost formation process is developed by means of a finite volume approach. Emphasis is put on the frost surface boundary condition as well as the wide range of empirical correlations related to the thermophysical and transport properties of frost. A study of the numerical solution is made, establishing the parameters that ensure grid independence. Attention is given to the algorithm, the discretised equations and the code optimization through dynamic relaxation techniques. A critical analysis of four cases is carried out by comparing solutions of several empirical models against tested experiments. As a result, a discussion on the performance of such parameters is started and a proposal of the most suitable models is presented.

  11. Heat and mass transfer in the melting of frost

    Mohs, William F

    2015-01-01

    This Brief is aimed at engineers and researchers involved in the refrigeration industry: specifically, those interested in energy utilization and system efficiency. The book presents what the authors believe is the first comprehensive frost melting study involving all aspects of heat and mass transfer. The volume’s description of in-plane and normal digital images of frost growth and melting is also unique in the field, and the digital analysis technique offers an advantage over invasive measurement methods. The scope of book’s coverage includes modeling and experimentation for the frost formation and melting processes. The key sub-specialties to which the book are aimed include refrigeration system analysis and design, coupled heat and mass transfer, and phase-change processes.

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

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

    2006-06-01

    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.

  13. Analysis of railway subgrade frost heave deformation based on GPS

    Fuxun Ma

    2016-03-01

    Full Text Available In order to analyze the connection between the railway subgrade frost heave deformation and temperature variation, five GPS stations' data were used to monitor the deformation on a certain section of railway subgrade in northeast China. GAMIT software is used to process the data, providing daily solution, daytime solution and nighttime solution. Vertical trends of these five stations were analyzed to investigate frost heave effect on railway subgrade deformation. The results show that the temperature difference between daytime and night induces stations, significant vertical displacement, and the temperature difference between seasons causes settlement of station which appears linear trend.

  14. Frost's "The Death of the Hired Man" Tagged and Numbered

    2001-01-01

    "Death of the Hired Man" es un poema de Robert Frost que ha recibido una importante atención de la crítica. Este trabajo no trata de discutir la significación de estas interpretaciones, sino plantear la invitación que el autor hace abiertamente a que sus lectores se involucren, cada cual a su forma, con su arte. Resulta interesante cómo Frost pide que se 'ocupen' de sus poemas todo tipo de lectores. ESto permite que cualquier lector experimente el placer de 'ver' y 'oír' lo que otros lectores...

  15. Analysis on the Climate Variation Characteristics of Frost in Shandong Province

    2011-01-01

    [Objective] The research aimed to study the climate variation characteristics of frost in Shandong Province. [Method] The daily minimum surface temperature ≤ 0 ℃ in autumn or spring was as the frost index. Based on the daily minimum surface temperature data in 67 meteorological observatories of Shandong Province during 1961-2008, the variation characteristics of first, last frost dates and frost-free period in Shandong Province were analyzed by using the climate diagnosis analysis method. [Result] The clima...

  16. Risk analysis of first and last frost occurrences in central Alborz region, Iran

    Rahimi, M.; Khalili, A.; Hajjam, S.; Kamali, G.A.; Stigter, C.J.

    2007-01-01

    Central Alborz is one of the important agricultural regions of Iran. Occurrence of the first frost in fall and the last frost in spring causes damage to the crops in this region every year. Information about the probable dates of frost occurrence helps farmers in preventing or reducing the damages c

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

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede; Laustsen, Sara

    2013-01-01

    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....

  18. 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

    Velásquez Valencia Henry

    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

  19. 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

    Escobar Chalarca Carlos Alberto

    2007-09-01

    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

  20. Stylistic Analysis of the Road Not Taken by Robert Frost

    蒋庆

    2014-01-01

    The Road Not Taken is one of the famous poems created by Robert Frost, a celebrated poet in American modern literature. With the reference to the stylistic theory, the author of this paper will analyze respectively the sound patterning, grapheme, lexicon, syntax of the poem.

  1. Annual variations of frost table in Kangerlussuaq Airport, western Greenland

    2007-01-01

    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...

  2. Commentary of Wind and Window Flower by Robert Frost

    张磊

    2011-01-01

    Wind and Window Flower is a special metaphorical love poem by Robert Frost. This tale of love actually presents a love journey of temptation, excitement, and disappointment. This paper tries to analysis the poem from the perspective of the sound of the poetry, the metro and rhyme, the conceptual and rhetorical.

  3. Genetic architecture of winter hardiness and frost tolerance in triticale.

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

    2014-01-01

    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.

  4. Condensation phenomena and frost problems in the air heat recuperators

    Adamski Mariusz

    2014-01-01

    Full Text Available Investigation results of condensation phenomena and frost problems in the ventilation heat recuperators are presented. The experiments have been conducted for typical value of indoor temperature 20°C and a large range of humidity values from 20 to 75% and more of an exhausted air. The heat exchanger worked in the real conditions of the winter climate in Bialystok.

  5. Jeff FROST, video artist for U2, visits CERN

    2015-01-01

    Video artist Jeff Frost came to CERN last April to produce video art for the U2 band's 2015 tour Innocence and Experience. He spent a week and visited in The Globe, the ATLAS, CMS experiments and ALICE caverns, Idea Square, the COMPASS experiment, the AD, the Aegis experiment, n-ToF, LEIR, ISOLDE, SM18, the Computing Centre.

  6. Genetic architecture of winter hardiness and frost tolerance in triticale.

    Wenxin Liu

    Full Text Available 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.

  7. 黄土高原及周边地区土壤有机质对现代土壤磁化率的影响%Impact of soil organic matter on modern soil magnetic susceptibility in Loess Plateau and its surrounding areas

    张博; 刘卫国

    2016-01-01

    Background, aim, and scope Magnetic susceptibility of soils can provide paleoclimatic information. In Chinese Loess Plateau, susceptibility enhancement is usually considered as a proxy of monsoon intensity. Several hypotheses were used to explain variations of this proxy. Here, we present a study on how soil magnetic susceptibility is related with soil organic matters. We analyzed magnetic susceptibility, organic carbon content, organic carbon isotopic composition, and C/N ratio of modern soils from Chinese Loess Plateau, in order to obtain the relationship between soil magnetic susceptibility and other parameters, as well as how soil organic matters affect soil magnetic susceptibility. Materials and methods Fifty modern soil samples were collected from the Loess Platform, forest areas at the Huangling and Huanglong Mount, and loess-desert area near the Tengger Desert. These soil samples represent modern soil types in the Loess Plateau. Samples were collected 2—3 cm below the surface. The sampling sites are at least 40 km away from any industrialized centers that could generate artificial, air-borne magnetic material. In this way, we minimized the effect of human and livestock activity. We tested magnetic susceptibility (χlf), organic carbon isotopic composition (δ13C), and organic carbon and nitrogen contents of these samples. Results The magnetic susceptibility varied from 26.6×10−8 m3∙kg−1 to 61.4×10−8 m3∙kg−1 for soils from the loess platform, and from 68.6×10−8 m3∙kg−1 to 107.5×10−8 m3∙kg−1 for soils from forest areas. The value of soil from forest areas is apparently higher than that from the loess platform. The magnetic susceptibility of soil samples from loess-desert area varied from 8.5×10−8 m3∙kg−1 to 44.4×10−8 m3∙kg−1.δ13C values of soil samples from the loess platform varied from−22‰to−24.4‰.δ13C values of soil samples from loess-desert area varied from−20.66‰to−24.69‰, whose range is

  8. Gamma-ray spectrometry, electrical resistivity, and magnetic susceptibility of agricultural soils in the Northwest region of the Parana State, Brazil; Gamaespectrometria, resistividade eletrica e susceptibilidade magnetica de solos agricolas no noroeste do estado do Parana

    Becegato, Valter Antonio [Universidade do Estado de Santa Catarina-UDESC, Centro de Ciencias Agroveterinarias, Lages, SC (Brazil); Ferreira, Francisco Jose Fonseca, E-mail: becegato@cav.udesc.br, E-mail: francisco.ferreira@ufpr.br [Universidade Federal do Parana (LPGA/UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Lab. de Pesquisas em Geofisica Aplicada

    2005-10-15

    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{sup -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 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)

  9. Borehole Heat Exchanger Systems: Hydraulic Conductivity and Frost-Resistance of Backfill Materials

    Anbergen, Hauke; Sass, Ingo

    2016-04-01

    constant radial stress boundary conditions (sigma 2 = sigma 3 = constant) • radial freezing from inside out, following the in-situ freezing direction The results differ substantially from prior test procedures (such as standardized frost tests for concrete or soft soils). Concentric frost-induced cracking was observed. The cracking pattern is in good agreement with cryostatic suction processes and frost heave in fine grained soils. The hydraulic conductivity of the system depends on the composition of the grout. With the developed testing device (and procedure) a unified and independent assessment and quality control becomes feasible. Adequate materials for advanced shallow geothermal systems can be clearly identified.

  10. Frost Crack Impact on European Beech (Fagus sylvatica L. Wood Quality

    Vasile R. CÂMPU

    2015-04-01

    Full Text Available Frost crack represents one of the main defects which affect European beech wood quality. Therefore, the purpose of this paper is to improve the knowledge regarding both the impact of frost crack on European beech wood quality and the frost crack characteristics which affect wood quality. In order to do this, nineteen European beech trunks with frost crack have been studied. Each trunk has been cross-cut every 1 meter and the characteristics of frost crack and frost crack star-shaped heart have been measured in each cross-cut section. The defects which accompany frost crack have also been identified in each cross-cut section. Moreover, the possibility of determining these defects using the IML RESIF500 – S Resistograph has been tested. The research has emphasized the existence of statistical correlations between frost crack star-shaped heart expansion, frost crack rib prominence and frost crack length. These correlations are expressed by multiple linear regressions. The presence of defects which affect wood structure leading to a decrease in penetration resistance can be determined accurately with the resistograph. Decay (in frost cracks older than 8 years and ring shake have been identified as the most frequent defects which accompany frost crack. The measurements made on the frost cracks studied have been gathered in a graph which shows frost crack impact on European beech wood quality. The results obtained lead to the improvement of the criteria of European beech wood quality assessment by expanding the already existent knowledge and by identifying new aspects which may complete standing wood quality determination and sorting methods.

  11. Modelling shallow landslide susceptibility by means of a subsurface flow path connectivity index and estimates of soil depth spatial distribution

    C. Lanni

    2012-11-01

    Full Text Available Topographic index-based hydrological models have gained wide use to describe the hydrological control on the triggering of rainfall-induced shallow landslides at the catchment scale. A common assumption in these models is that a spatially continuous water table occurs simultaneously across the catchment. However, during a rainfall event isolated patches of subsurface saturation form above an impeding layer and their hydrological connectivity is a necessary condition for lateral flow initiation at a point on the hillslope.

    Here, a new hydrological model is presented, which allows us to account for the concept of hydrological connectivity while keeping the simplicity of the topographic index approach. A dynamic topographic index is used to describe the transient lateral flow that is established at a hillslope element when the rainfall amount exceeds a threshold value allowing for (a development of a perched water table above an impeding layer, and (b hydrological connectivity between the hillslope element and its own upslope contributing area. A spatially variable soil depth is the main control of hydrological connectivity in the model. The hydrological model is coupled with the infinite slope stability model and with a scaling model for the rainfall frequency–duration relationship to determine the return period of the critical rainfall needed to cause instability on three catchments located in the Italian Alps, where a survey of soil depth spatial distribution is available. The model is compared with a quasi-dynamic model in which the dynamic nature of the hydrological connectivity is neglected. The results show a better performance of the new model in predicting observed shallow landslides, implying that soil depth spatial variability and connectivity bear a significant control on shallow landsliding.

  12. FROST: an ASIC for digital mammography with synchrotron radiation

    Bergamaschi, A. E-mail: bergamaschi@ts.infn.it; Prest, M.; Vallazza, E.; Arfelli, F.; Dreossi, D.; Longo, R.; Olivo, A.; Pani, S.; Castelli, E

    2003-09-01

    The FRONTier RADiography (FRONTRAD) collaboration is developing a digital system for mammography at the Elettra Synchrotron Light Source in Trieste. The system is based on a silicon microstrip detector array. The ASIC FROST (FRONTRAD Read Out sySTem) was developed as a collaboration between INFN Trieste and Aurelia Microelettronica and is designed to operate in single photon counting mode. FROST provides low-noise and high-gain performances and is able to work at incident photon rates higher than 100 kHz with almost 100% efficiency. The ASIC has been tested and the first images of mammographic test objects will be shown. The acquisition time per breast image should be of about 10 s.

  13. Mechanisms of frost adaptation and freeze damage in grapevine buds

    Badulescu Valle, Radu Virgil

    2002-01-01

    Mechanisms of frost hardening in compound (latent) buds of the grapevine cultivar ?Bacchus? were tested with different methods during three winters. The investigated parameters were LTE/HTE (low temperature exotherm/high temperature exotherm), water content, starch, sugar- and anions combination and bud histology. Water content from wood and buds was determined regularly every 2 weeks from March 1998 until Mai 2000. The lowest water content in wood and buds (about 40 %) was found ...

  14. Effects of environmental factors and management practices on microclimate, winter physiology, and frost resistance in trees.

    Charrier, Guillaume; Ngao, Jérôme; Saudreau, Marc; Améglio, Thierry

    2015-01-01

    Freezing stress is one of the most important limiting factors determining the ecological distribution and production of tree species. Assessment of frost risk is, therefore, critical for forestry, fruit production, and horticulture. Frost risk is substantial when hazard (i.e., exposure to damaging freezing temperatures) intersects with vulnerability (i.e., frost sensitivity). Based on a large number of studies on frost resistance and frost occurrence, we highlight the complex interactive roles of environmental conditions, carbohydrates, and water status in frost risk development. To supersede the classical empirical relations used to model frost hardiness, we propose an integrated ecophysiologically-based framework of frost risk assessment. This framework details the individual or interactive roles of these factors, and how they are distributed in time and space at the individual-tree level (within-crown and across organs). Based on this general framework, we are able to highlight factors by which different environmental conditions (e.g., temperature, light, flood, and drought), and management practices (pruning, thinning, girdling, sheltering, water aspersion, irrigation, and fertilization) influence frost sensitivity and frost exposure of trees.

  15. Plant resistance to cold stress: Mechanisms and environmental signals triggering frost hardening and dehardening

    Erwin H Beck; Richard Heim; Jens Hansen

    2004-12-01

    This introductory overview shows that cold, in particular frost, stresses a plant in manifold ways and that the plant’s response, being injurious or adaptive, must be considered a syndrome rather than a single reaction. In the course of the year perennial plants of the temperate climate zones undergo frost hardening in autumn and dehardening in spring. Using Scots pine (Pinus sylvestris L.) as a model plant the environmental signals inducing frost hardening and dehardening, respectively, were investigated. Over 2 years the changes in frost resistance of Scots pine needles were recorded together with the annual courses of day-length and ambient temperature. Both act as environmental signals for frost hardening and dehardening. Climate chamber experiments showed that short day-length as a signal triggering frost hardening could be replaced by irradiation with far red light, while red light inhibited hardening. The involvement of phytochrome as a signal receptor could be corroborated by respective night-break experiments. More rapid frost hardening than by short day or far red treatment was achieved by applying a short period (6 h) of mild frost which did not exceed the plant’s cold resistance. Both types of signals were independently effective but the rates of frost hardening were not additive. The maximal rate of hardening was – 0.93°C per day and frost tolerance of < – 72°C was achieved. For dehardening, temperature was an even more effective signal than day-length.

  16. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Or Sperling

    Full Text Available Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq. cm(-3 yr(-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  17. Inheritance of autumn frost hardiness in Pinus sylvestris L. seedlings.

    Norell, L; Eriksson, G; Ekberg, I; Dormling, I

    1986-07-01

    Inheritance of frost hardiness was analysed making use of a 12×12 incomplete factorial mating design. Owing to space limitations only 59 families could be tested in four experiments. To link the four experiments, some families were common to two or more experiments. The seedlings were grown in climate chambers under conditions inducing autumn hardening. The plants were exposed to a freezing temperature of -10 °C for three hours at night lengths of 11-13 h. A statistical model was developed for analyses of variance of our data. The genetic variation and the variation due to the cultivation regimes during autumn hardening were of the same magnitude. The additive effects were the most important ones for induction of frost damage. No interaction following long-distance crossing was noted. Mixed model equations were used for ranking of the parents. The results obtained support a polygenic inheritance of frost hardiness. The large within-population variation offers good opportunities for hardiness breeding.

  18. Seasonal frost conditions and permafrost regime distribution in the high lands of Sierra Nevada (Spain)

    Oliva, Marc; Gómez-Ortiz, Antonio; Salvador-Franch, Ferran; Salvà-Catarineu, Montserrat; Palacios, David; Tanarro, Luis Miguel; Ramos, Miguel

    2016-04-01

    Sierra Nevada, Southern Spain (37°S, 3°W), is the massif including the southernmost permafrost remnants in Europe. Over the last decades the distribution of permafrost in this massif has been examined through a combined approach including geomorphological, geophysical and monitoring studies. The purpose of this communication is to summarize all the studies relating to soil thermal regime in the high lands of Sierra Nevada. A 114.5 m deep borehole was drilled in 2000 in the Veleta summit (3380 m) in order to monitor soil temperatures in the summits of the massif. No permafrost regime was detected, with average temperatures stabilizing at 20 m depth at 2 °C. Seasonal frost conditions were also detected in periglacial landforms such as solifluction lobes and sorted-circles. In the Rio Seco cirque the mean annual temperatures in a solifluction lobe located in a southern glacial cirque of the massif (3005 m) were 3.9 °C at 1 m depth between 2006 and 2012; in the north-exposed San Juan valley, soil temperatures in another solifluction landform (2864 m) were 3.9 °C at 1 m depth between 2003 and 2012. In a sorted-circle located in the high plateau of Cerro de los Machos (3297 m) soil temperatures recorded an average of 1.7 °C at 50 cm depth between 2003 and 2011. The only place where temperatures were permanently negative was inside of the only active rock glacier distributed in the Veleta cirque, on the northern slope of the Veleta peak. Here, the remnants of a small glacier that existed during the Little Ice Age (LIA) are still present in the form of buried ice and permafrost buried under the boulders of this rock glacier. Temperatures averaged 0.2 °C at 1 m depth between 2006 and 2013, with permanently negative temperatures below this level until, at least, 10 m depth. Consequently, seasonal frost is widespread nowadays in most of the Sierra Nevada, with permafrost conditions strongly conditioned by the geomorphological setting and the recent environmental

  19. SO2 frost - UV-visible reflectivity and Io surface coverage

    Nash, D. B.; Fanale, F. P.; Nelson, R. M.

    1980-01-01

    The reflectance spectrum in the range 0.24-0.85 microns of SO2 frost is measured in light of the discovery of SO2 gas in the atmosphere of Io and the possible discovery of the frost on its surface. Frost deposits up to 1.5 mm thick were grown in vacuum at 130 K and bi-directional reflectance spectra were obtained. Typical SO2 frost is found to exhibit very low reflectivity (2-5%) at 0.30 microns, rising steeply at 0.32 microns to attain a maximum reflectivity (75-80%) at 4.0 microns and uniformly high reflectivity throughout the visible and near infrared. Comparison with the full disk spectrum of Io reveals that no more than 20% of the surface can be covered with optically thick SO2 frost. Combinations of surface materials including SO2 frost which can produce the observed spectrum are indicated.

  20. Early spring, severe frost events, and drought induce rapid carbon loss in high elevation meadows.

    Chelsea Arnold

    Full Text Available By the end of the 20th century, the onset of spring in the Sierra Nevada mountain range of California has been occurring on average three weeks earlier than historic records. Superimposed on this trend is an increase in the presence of highly anomalous "extreme" years, where spring arrives either significantly late or early. The timing of the onset of continuous snowpack coupled to the date at which the snowmelt season is initiated play an important role in the development and sustainability of mountain ecosystems. In this study, we assess the impact of extreme winter precipitation variation on aboveground net primary productivity and soil respiration over three years (2011 to 2013. We found that the duration of snow cover, particularly the timing of the onset of a continuous snowpack and presence of early spring frost events contributed to a dramatic change in ecosystem processes. We found an average 100% increase in soil respiration in 2012 and 2103, compared to 2011, and an average 39% decline in aboveground net primary productivity observed over the same time period. The overall growing season length increased by 57 days in 2012 and 61 days in 2013. These results demonstrate the dependency of these keystone ecosystems on a stable climate and indicate that even small changes in climate can potentially alter their resiliency.

  1. Discovery of a widespread low-latitude diurnal CO2 frost cycle on Mars

    Piqueux, Sylvain; Kleinböhl, Armin; Hayne, Paul O.; Heavens, Nicholas G.; Kass, David M.; McCleese, Daniel J.; Schofield, John T.; Shirley, James H.

    2016-07-01

    While the detection of CO2 ice has only been reported outside the Martian polar regions at very high elevation (i.e., Elysium, Olympus Mons, and the Tharsis Montes), nighttime surface observations by the Mars Climate Sounder on board the Mars Reconnaissance Orbiter document the widespread occurrence of atmospherically corrected ground temperatures consistent with the presence of extensive carbon dioxide frost deposits in the dusty low thermal inertia units at middle/low latitudes. Thermal infrared emissivities, interpreted in conjunction with mass balance modeling, suggest micrometer size CO2 ice crystals forming optically thin layers never exceeding a few hundreds of microns in thickness (i.e., 10-2 kg m-2) locally, which is insufficient to generate a measurable diurnal pressure cycle (atmosphere). Atmospheric temperatures at middle/low latitudes are not consistent with precipitation of CO2 ice, suggesting that condensation occurs on the surface. The recurring growth and sublimation of CO2 ice on Martian dusty terrains may be an important process preventing soil induration and promoting dynamic phenomena (soil avalanching and fluidization and regolith gardening), maintaining a reservoir of micrometer size dust particles that are mobile and available for lifting. The discovery of this diurnal CO2 cycle represents an important step forward in our understanding of the way the Martian atmosphere interacts with the surface.

  2. Use of Hyperbaric Oxygen in Experimental Frost-Bite

    Bal Krishna

    1978-04-01

    Full Text Available Frost bite produced in rates by exposing them to -15 degree calcius and the extent of injury in the hind limbs and the tail was assessed at the end of 15 days. Hyperoxic treatment at normal atmospheric pressure and 1.5 atmosphere was given to experimental groups for 30 minutes daily for seven days in a hyperoxic chamber immediately after cold exposure. The controls were not given any treatment. Single oxygen treatment at normal atmosphere pressure was of no value, however, repeated hyperoxic treatment showed limited improvement but repeated treatment for seven days with hyperbaric oxygen at 1.5 atmosphere showed distinct recovery of frozen parts.

  3. Nowcasting in the FROST-2014 Sochi Olympic project

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

    2013-04-01

    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

  4. Frost resistance of concrete with crushed brick as aggregate

    Janković Ksenija

    2010-01-01

    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.

  5. An Archetypal Study of Plant Imagery in Robert Frost's Poems

    邱芬芬

    2016-01-01

    As one of the most popular American poets in the twentieth century, Robert Frost demonstrated myriads of universally acknowledged works to the world. This paper aims to analyze the plant imagery appearing in his poems from the perspective of archetypal theory. This study, on the basis of analyzing poetic texts, utilizes content analysis to classify plant images into four types and work out relevant statistics. After data analysis based on thematology and archetypal theory, the study finds that plant images in his poems demonstrate the relationship between human beings and nature, psychological conflicts of the poet, death and dismay, expectation for life and rebirth.

  6. Effects of mid-season frost and elevated growing season temperature on stomatal conductance and specific xylem conductivity of the arctic shrub, Salix pulchra

    Gorsuch, D. M.; Oberbauer, S. F. [Florida International Univ., Dept. of Biological Sciences, Miami, FL (United States)

    2002-10-01

    It is hypothesized that because deciduous plants have a growth season limited in length and also have generally larger conduit volumes, they are more likely to be injured by freeze-thaw induced cavitation during the growing season. To test this hypothesis, the deciduous arctic shrub, Salix pulchra, was grown in simulated Alaskan summer temperatures and at five degrees C above the ambient simulation in controlled environments. Specific hydraulic conductivity and leaf stomatal conductance were measured in plants grown at both temperatures before and after freeze treatment simulating a mid-season frost. Before freeze treatment specific hydraulic conductivity was 2.5 times higher and stomatal conductance was 1.3 times higher in plants grown at elevated temperature. After freeze treatment reduction in hydraulic conductivity and stomatal conductance was 3.5 and 1.8 times higher in the plants grown at the higher temperature than plants grown at ambient temperature. Plants grown at the higher temperature also had larger vessel diameters and higher vessel densities than ambient-grown plants. These results suggest that higher growing season temperatures will make arctic deciduous shrubs more susceptible to frost damage. The implication of these results for plant growth in the arctic tundra is that while climate warming favours plants with larger vessels and higher specific xylem conductivity over plants with lower values, this competitive advantage may be lost if there is an increase in the risk of frost during the growing season. 43 refs., 5 figs.

  7. Prediction of Frost Occurrences Using Statistical Modeling Approaches

    Hyojin Lee

    2016-01-01

    Full Text Available We developed the frost prediction models in spring in Korea using logistic regression and decision tree techniques. Hit Rate (HR, Probability of Detection (POD, and False Alarm Rate (FAR from both models were calculated and compared. Threshold values for the logistic regression models were selected to maximize HR and POD and minimize FAR for each station, and the split for the decision tree models was stopped when change in entropy was relatively small. Average HR values were 0.92 and 0.91 for logistic regression and decision tree techniques, respectively, average POD values were 0.78 and 0.80 for logistic regression and decision tree techniques, respectively, and average FAR values were 0.22 and 0.28 for logistic regression and decision tree techniques, respectively. The average numbers of selected explanatory variables were 5.7 and 2.3 for logistic regression and decision tree techniques, respectively. Fewer explanatory variables can be more appropriate for operational activities to provide a timely warning for the prevention of the frost damages to agricultural crops. We concluded that the decision tree model can be more useful for the timely warning system. It is recommended that the models should be improved to reflect local topological features.

  8. Frost & Sullivan Recognizes. ZTE as. 2011 LTE Vendor of the Year

    2011-01-01

    ZTE Corporation announced on November 10, 2011 that it has been named LTE Vendor of the Year by leading consulting firm Frost & Sullivan. The Frost & Sullivan LTE Vendor of the Year award is given to companies that have achieved excellence in LTE. ZTE won the award for its growing number of secured contracts and also for its patent applications.

  9. Past and future changes in frost day indices on Catskill Mountains region of New York

    Changes in frost indices in New York's Catskill Mountains region, the location of water supply reservoirs for New York City, have potentially important implications. Frost day is defined as a day with Tmin < 0 deg C. The objective of this study was to investigate past and predicted changes in minimu...

  10. Making a case for breeding frost tolerant potatoes adapted to Andean Highlands especially the Altiplano

    Although cultivated potatoes are sensitive to mild frost (severely damaged at air temperatures below -2 or -3 C) limited progress has been made in developing frost hardy cultivars. This may be due to the fact that most potato crop grown in North America and Europe has minimal risk to be subjected to...

  11. Activating the microscale edge effect in a hierarchical surface for frosting suppression and defrosting promotion.

    Chen, Xuemei; Ma, Ruiyuan; Zhou, Hongbo; Zhou, Xiaofeng; Che, Lufeng; Yao, Shuhuai; Wang, Zuankai

    2013-01-01

    Despite extensive progress, current icephobic materials are limited by the breakdown of their icephobicity in the condensation frosting environment. In particular, the frost formation over the entire surface is inevitable as a result of undesired inter-droplet freezing wave propagation initiated by the sample edges. Moreover, the frost formation directly results in an increased frost adhesion, posing severe challenges for the subsequent defrosting process. Here, we report a hierarchical surface which allows for interdroplet freezing wave propagation suppression and efficient frost removal. The enhanced performances are mainly owing to the activation of the microscale edge effect in the hierarchical surface, which increases the energy barrier for ice bridging as well as engendering the liquid lubrication during the defrosting process. We believe the concept of harnessing the surface morphology to achieve superior performances in two opposite phase transition processes might shed new light on the development of novel materials for various applications.

  12. Dynamic behavior of a direct expansion evaporator under frosting condition. Part I. Distributed model

    Tso, C.P. [Multimedia University, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore 634798 (Singapore). School of Mechanical and Aerospace Engineering

    2006-06-15

    A general distributed model with two-phase flow for refrigerant coupled with a frost model is developed for studying the dynamic behavior of an evaporator. The equations are derived in non-steady-state manner for the refrigerant and a quasi-steady state model with permeation for the frost. The complex flow and geometry of the finned tube evaporator lead to uneven wall and air temperature distributions, which in turn affect the rate of frost growth and densification along the coil depth. Results include frost accumulation and its effect on energy transfer, air off-coil temperature, refrigerant liquid dry-out position and propagation of frost formation along the coil. (author)

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

    Galley, R.J.; Else, B.G.T.; Geilfus, Nicolas-Xavier;

    2015-01-01

    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......-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...

  14. Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbeds in seasonally frozen ground regions

    Chang Yuan; FuJun Niu; QiHao Yu; XinBin Wang; Lei Guo; YanHui You

    2015-01-01

    The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation (between October 2012 and January 2013), and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements — black pavement and insulation-black pavement — to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field con-ditions of the Changchun section (D3K692+840 to D3K692+860). The results show that: (1) Compared with cement pave-ment, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth; (2) the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3–1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7–0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7–8 mm, which would meet the deformation limit established by theCode for Design on Special Subgrade of Railway; (3) the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and (4) compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds.

  15. Combating Frosting with Joule-Heated Liquid-Infused Superhydrophobic Coatings.

    Elsharkawy, Mohamed; Tortorella, Domenico; Kapatral, Shreyas; Megaridis, Constantine M

    2016-05-03

    Frost formation is omnipresent when suitable environmental conditions are met. A good portion of research on combating frost formation has revolved around the passive properties of superhydrophobic (SHPO) and slippery lubricant-impregnated porous (SLIP) surfaces. Despite much progress, the need for surfaces that can effectively combat frost formation over prolonged periods still remains. In this work, we report, for the first time, the use of electrically conductive SHPO/SLIP surfaces for active mitigation of frost formation. First, we demonstrate the failure of these surfaces to passively avert prolonged (several hours) frosting. Next, we make use of their electroconductive property for active Joule heating, which results in the removal of any formed frost. We study the role of the impregnating lubricant in the heat transfer across the interface, the surface, and the ambient. We show that, even though the thermal properties of the impregnating lubricant may vary drastically, the lubricant type does not noticeably affect the defrosting behavior of the surface. We attribute this outcome to the dominant thermal resistance of the thick frost layer formed on the cooled surface. We support this claim by drawing parallels between the present system and heat transfer through a one-dimensional (1D) composite medium, and solving the appropriate transient transport equations. Lastly, we propose periodic thermal defrosting for averting frost formation altogether. This methodology utilizes the coating's passive repellent capabilities, while eliminating the dominant effect of thick deposited frost layers. The periodic heating approach takes advantage of lubricants with higher thermal conductivities, which effectively enhance heat transfer through the porous multiphase surface that forms the first line of defense against frosting.

  16. The magnetic susceptibility characteristic and its environmental significance of roadside soil in Xi′an city%西安城市路边土壤磁化率特征及其环境意义

    陈景辉; 卢新卫

    2011-01-01

    采集西安城市主干道路边表层土壤样品,分析了土壤样品的理化指标及As、Co、Cr、Cu、Mn、Ni、Pb和Zn的含量,并测定了样品的磁化率.结果表明:土壤样品的低频和高频磁化率均值分别为181.7×10-8和171.9×10-8m3/kg;低频和高频磁化率与烧失量和沙粒含量呈显著正相关,与黏粒和粉砂粒含量呈显著负相关,与Co、Cu、Pb和Zn含量呈显著正相关,与Mn含量呈显著负相关,与As、Co、Cr、Cu、Mn、Ni、Pb和Zn 8种元素的污染负荷指数呈显著正相关.磁化率可以指示西安城市路边土壤重金属的整体污染水平,可以反映路边土壤磁性升高的主要人为源为交通污染及工业企业排放.%The physio-chemical indicators,heavy metal concentrations of As,Co,Cr,Cu,Mn,Ni,Pb,Zn and magnetic susceptibility in the roadside soils collected from the main streets of Xi′an city were determined.The results showed that the average values of low and high frequency magnetic susceptibility are 181.7×10-8 and 171.9×10-8 m3/kg,respectively.The low and high frequency magnetic susceptibility are positive correlated with loss on ignition(LOI) and sand content significantly,while negative correlated with clay and silt content significantly.Low and high frequency magnetic susceptibility are also positive correlated with Co,Cu,Pb and Zn significantly,but negative correlated with Mn significantly.The pollution loading index of As,Co,Cr,Cu,Mn,Ni,Pb and Zn is also positive correlated with low and high frequency magnetic susceptibility significantly.The magnetic susceptibility can indicate the pollution level of heavy metal in roadside soil of Xi′an city,and reflect traffic pollution and industrial activities emissions are the main human sources leading to soil magnetism rising.

  17. 小型灌区渠道抗冻胀方案探讨%A Discussion of Channel Frost Heave Resistance Program on Small-sized Irrigation Area

    朱琳

    2016-01-01

    季节性冻土地区的基土冻胀破坏会降低渠道水利用系数.在抗冻胀设计中,常用的防止冻胀措施为预制C15混凝土+砂砾石垫层弧底梯形渠和预制C15混凝土+聚笨乙烯泡沫板弧底梯形渠两种衬砌形式.通过在小型灌区渠道改建设计中对比两种措施分别在两种常见的断面型式下投资直接费用,得出在小型渠道抗冻胀措施中砂砾石垫层方案投资经济具有一定的优势.%On seasonally frozen ground area,frost heave damages of base soil will reduce channel water uti-lization coefficient.In the frost heave resistance design,the frost heave resistance measures commonly used have two lining forms,which are trapezoidal channel with arc bottom of prefabricate C15 concrete plus sand and gravel stratum and of prefabricate C15 concrete plus polystyrene foam board.The comparison of direct investment cost of two different measures respectively under two commonly sectional forms from designs of channel reconstruction of small-sized irrigation area indicates that the sand and gravel stratum program in the frost heave resistance measure of small-sized channel has a certain advantage in investment economy.

  18. Can the Frost Multidimensional Perfectionism Scale Assess Perfeccionismo?

    Burgess, Alexandra M; DiBartolo, Patricia Marten; Rendón, María Jose

    2016-08-08

    Although culture-based measurement bias threatens the validity of intergroup comparison research, measurement invariance is often assumed rather than demonstrated by researchers who draw conclusions about cross-cultural similarities or differences. The current article investigates the cross-cultural invariance of a popular measure of perfectionism, the Frost Multidimensional Perfectionism Scale (F-MPS; Frost, Marten, Lahart, & Rosenblate, 1990) for a Hispanic/Latina sample. Perfectionism, which encompasses high goal setting and sensitivity to critical evaluation, is a transdiagnostic risk factor for internalizing psychopathology that especially warrants focus among groups burdened by mental health disparities. Multiple samples were used in a series of analyses to construct a baseline first-order measurement model and test for cross-group equivalence. For model development, confirmatory factor analyses (CFAs) were used with 320 female participants (Mage = 19.61 years) who identified primarily (n = 301) as European/European American. Measurement invariance testing was conducted with multigroup CFAs using another sample of female adults (n = 574; Mage = 21.21 years), identifying either as European/European American (n = 217) or Hispanic/Latina/Latin American (n = 357). Evidence was found for invariance across the revised F-MPS factor structure, pattern of factor loadings, and factor variances/covariances. Results indicate that predictive relationships may be compared across these groups, but caution is suggested when interpreting raw mean score differences due to intercept nonequivalence. Further, second-order model testing demonstrated support for the bidimensional model of perfectionism cross-culturally. Future research on perfectionism within the Latino/a population is encouraged using this equivalent item set. (PsycINFO Database Record

  19. Acclimation of Pistacia integerrima trees to frost in semi-arid environments depends on autumn's drought.

    Sperling, Or; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2017-03-01

    Main conclusion Cold acclimation is revealed through induced stem respiration during pre-winter frost of native Pistacia integerrima trees in continental semi-arid environments. Semi-arid environments challenge vegetation by simultaneous abiotic stresses. In this study, we examine the combined effects of water stress and frost on the physiology of Pistacia integerrima stems. This species is native to semi-arid environments where drought and frost frequently co-occur. We quantified carbohydrates and proline in P. integerrima stems responding to frost and experiencing water potentials between -0.2 and -1.8 MPa. We report that dehydrated trees (i.e., Ψstem <=-1 MPa) had more soluble sugars and proline than the well-watered trees (-0.2 MPa). The dehydrated trees also froze at lower temperatures and were less damaged by freezing. Interestingly, we observed a significant increase in stem CO2 efflux at near-freezing temperatures that could be linked to frost protection. This novel finding challenges current paradigm of plant respiration-kinetics which predicts, according to Arrhenius equation, lower respiration rates during frost. Our results support the notion that drought and frost are analogous stresses that can independently activate corresponding physiological processes in trees and amplify protection. This inevitable stress response 'collaboration' may be the key to understanding how non-dormant perennial plants survive the highly variable weather patterns of early winters in semi-arid environments.

  20. Modeling of frost crystal growth over a flat plate using artificial neural networks and fractal geometries

    Tahavvor, Ali Reza

    2016-06-01

    In the present study artificial neural network and fractal geometry are used to predict frost thickness and density on a cold flat plate having constant surface temperature under forced convection for different ambient conditions. These methods are very applicable in this area because phase changes such as melting and solidification are simulated by conventional methods but frost formation is a most complicated phase change phenomenon consists of coupled heat and mass transfer. Therefore conventional mathematical techniques cannot capture the effects of all parameters on its growth and development because this process influenced by many factors and it is a time dependent process. Therefore, in this work soft computing method such as artificial neural network and fractal geometry are used to do this manner. The databases for modeling are generated from the experimental measurements. First, multilayer perceptron network is used and it is found that the back-propagation algorithm with Levenberg-Marquardt learning rule is the best choice to estimate frost growth properties due to accurate and faster training procedure. Second, fractal geometry based on the Von-Koch curve is used to model frost growth procedure especially in frost thickness and density. Comparison is performed between experimental measurements and soft computing methods. Results show that soft computing methods can be used more efficiently to determine frost properties over a flat plate. Based on the developed models, wide range of frost formation over flat plates can be determined for various conditions.

  1. Modeling of frost crystal growth over a flat plate using artificial neural networks and fractal geometries

    Tahavvor, Ali Reza

    2017-03-01

    In the present study artificial neural network and fractal geometry are used to predict frost thickness and density on a cold flat plate having constant surface temperature under forced convection for different ambient conditions. These methods are very applicable in this area because phase changes such as melting and solidification are simulated by conventional methods but frost formation is a most complicated phase change phenomenon consists of coupled heat and mass transfer. Therefore conventional mathematical techniques cannot capture the effects of all parameters on its growth and development because this process influenced by many factors and it is a time dependent process. Therefore, in this work soft computing method such as artificial neural network and fractal geometry are used to do this manner. The databases for modeling are generated from the experimental measurements. First, multilayer perceptron network is used and it is found that the back-propagation algorithm with Levenberg-Marquardt learning rule is the best choice to estimate frost growth properties due to accurate and faster training procedure. Second, fractal geometry based on the Von-Koch curve is used to model frost growth procedure especially in frost thickness and density. Comparison is performed between experimental measurements and soft computing methods. Results show that soft computing methods can be used more efficiently to determine frost properties over a flat plate. Based on the developed models, wide range of frost formation over flat plates can be determined for various conditions.

  2. Dynamic behavior of a direct expansion evaporator under frosting condition. Part II. Field investigation on a shipping container

    Tso, C.P. [Multimedia University, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore 634798 (Singapore). School of Mechanical and Aerospace Engineering

    2006-06-15

    A field investigation is performed on the frost formation at an evaporator of a commercial full-scale refrigerated container that uses R-12 as the working refrigerant. Results when compared with those from a numerical model presented earlier show that the model is capable of predicting the dynamic behavior of a direct expansion evaporator under both non-frosting and frosting conditions. The air outlet and energy transferred compare well between experiment and model, and within 20% for the air pressure drop. The frost occurrence and propagation agree well generally, with the frost formation first occurring at the first row where the refrigerant enters the evaporator. (author)

  3. 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

    Flávio P. de Oliveira

    2012-04-01

    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

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

    Barber, D.; Ehn, J.; Pucko, M.

    2014-01-01

    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...... 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 δ18O values indicated that frost flowers...... 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...

  5. Numerical Model on Frost Height of Round Plate Fin Used for Outdoor Heat Exchanger of Mobile Electric Heat Pumps

    Moo-Yeon Lee

    2012-01-01

    Full Text Available The objective of this study is to provide the numerical model for prediction of the frost growth of the round plate fin for the purpose of using it as a round plate fin-tube heat exchanger (evaporator under frosting conditions. In this study, numerical model was considering the frost density change with time, and it showed better agreement with experimental data of Sahin (1994 than that of the Kim model (2004 and the Jonse and Parker model (1975. This is because the prediction on the frost height with time was improved by using the frost thermal conductivity reflecting the void fraction and density of ice crystal with frost growth. Therefore, the developed numerical model could be used for frosting performance prediction of the round plate fin-tube heat exchanger.

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

    Nestor, Siim, 1974-

    2007-01-01

    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

  7. The susceptibility of soil enzymes to inhibition by leaf litter tannins is dependent on the tannin chemistry, enzyme class and vegetation history.

    Triebwasser, Daniella J; Tharayil, Nishanth; Preston, Caroline M; Gerard, Patrick D

    2012-12-01

    By inhibiting soil enzymes, tannins play an important role in soil carbon (C) and nitrogen (N) mineralization. The role of tannin chemistry in this inhibitory process, in conjunction with enzyme classes and isoforms, is less well understood. Here, we compared the inhibition efficiencies of mixed tannins (MTs, mostly limited to angiosperms) and condensed tannins (CTs, produced mostly by gymnosperms) against the potential activity of β-glucosidase (BG), N-acetyl-glucosaminidase (NAG), and peroxidase in two soils that differed in their vegetation histories. Compared with CTs, MTs exhibited 50% more inhibition of almond (Prunus dulcis) BG activity and greater inhibition of the potential NAG activity in the gymnosperm-acclimatized soils. CTs exhibited lower BG inhibition in the angiosperm-acclimated soils, whereas both types of tannins exhibited higher peroxidase inhibition in the angiosperm soils than in gymnosperm soils. At all of the tested tannin concentrations, irrespective of the tannin type and site history, the potential peroxidase activity was inhibited two-fold more than the hydrolase activity and was positively associated with the redox-buffering efficiency of tannins. Our finding that the inhibitory activities and mechanisms of MTs and CTs are dependent on the vegetative history and enzyme class is novel and furthers our understanding of the role of tannins and soil isoenzymes in decomposition.

  8. Risk Modelling of Late Spring Frost Damage on Fruit Trees, Case Study; Apple Tree, Mashhad Plain

    M Rahimi

    2012-02-01

    Full Text Available Mashhad plain is one of the most important regions of Apple cultivated areas. Occurring spring late frost creates a lot of damages on bud and decreasing the yield of Apple in this region. Assessment and risk modeling of frost damage would be useful to manage and decrease the damage. The study area is a part of Khorasan Razavi province which is located in Mashhad plain. This region is located in Northeast Iran (36º to 37 º N, 58 º 30' to 60 º E. The area of this region is about 13000 square km which is about one tenth of Khorasan province area. In order to modeling frost damage risk 12 affective parameters including climatological(Minimum temperature, temperature decreasing rate, temperature Increasing rate, Julian days of frost, cumulative degree days, Area under zero line, and frost duration and geographical parameters (Elevation, Longitude, Latitude, Aspect, and slope were selected. 3 damage full radiative frosts were selected in the period of Apple flowering time which was dated 20 April 2003, 8 April 2005, and 28 March 2005. Required meteorological data were collected from 9 meteorological standard stations inside and outside of study area. Linear multiple regression were used to modeling the relationship. The map for each parameter was plotted by using suitable interpolation method including IDW; Spline; Kriging. A grid map was defined with 5 by 5 kilometers to extract enough data for entering to the model. The regression equation was significant at the level of 99% significance. By using this equation the predicted amounts of frost risk damage were calculated for each point of grid and also the map was plotted. The regression equation of observed and predicted frost damage risk was provided by correlation of 0.93 and the error map also was prepared. According to this study in frost of 31 Farvardin 1388 South West parts of the plain estimated as the most frost risk areas by %53.19 and the southeast parts were estimated as the least

  9. Improving Anti-frosting Performance for Super-hydrophobic Nanocomposite Coatings

    Hao WANG; Xiao Min WU; Li Ming TANG; Wan Tian DAI; Feng You JIN

    2006-01-01

    New super-hydrophobic nanocomposite coatings were formed from modified nano-sized CaCO3 particles and polyacrylate at weight ratio of 9/1-8/2. SEM and XPS analysis indicated that such hydrophobicity could be attributed to the surface nano-microstructure and the surface enrichment of fluorine atoms. As the surface hydrophobicity increased, longer time was required for formation the initial frost, which makes super-hydrophobic coatings suitable for anti-frosting purpose.

  10. Spatiotemporal Variations in Snow and Soil Frost—A Review of Measurement Techniques

    Angela Lundberg

    2016-07-01

    Full Text Available Large parts of the northern hemisphere are covered by snow and seasonal frost. Climate warming is affecting spatiotemporal variations of snow and frost, hence influencing snowmelt infiltration, aquifer recharge and river runoff patterns. Measurement difficulties have hampered progress in properly assessing how variations in snow and frost impact snowmelt infiltration. This has led to contradicting findings. Some studies indicate that groundwater recharge response is scale dependent. It is thus important to measure snow and soil frost properties with temporal and spatial scales appropriate to improve infiltration process knowledge. The main aim with this paper is therefore to review ground based methods to measure snow properties (depth, density, water equivalent, wetness, and layering and soil frost properties (depth, water and ice content, permeability, and distance to groundwater and to make recommendations for process studies aiming to improve knowledge regarding infiltration in regions with seasonal frost. Ground-based radar (GBR comes in many different combinations and can, depending on design, be used to assess both spatial and temporal variations in snow and frost so combinations of GBR and tracer techniques can be recommended and new promising methods (auocostics and self potential are evolving, but the study design must be adapted to the scales, the aims and the resources of the study.

  11. The vulnerability of silver fir populations to damage from late frosts

    Klisz Marcin

    2016-03-01

    Full Text Available The aim of the study was to determine the vulnerability of selected silver fir populations to damage from late frost in the climatic conditions of south-eastern Poland. To determine the vulnerability of apical and lateral shoots to damage caused by late frosts, we observed four test plots in 2009 and 2014, each containing progenies of selected seed stands. Our statistical analyses were based on a model incorporating the following variables: site, year, type of frost damage, population as well as the possible interaction between these variables. Significant differences between the populations were found in terms of their sensitivity to damage from low temperature occurring during the growth period. Furthermore, we indirectly demonstrated differences in the severity of late frost on the experimental plots, as well as the intensity and variability of late frost shoot damage. Based on these results, we divided the studied populations into two groups of low (EF, KRA1 and NAR and high (LES2 and BAL2 sensitivity to late frost damage.

  12. Frost resistance of concrete surfaces coated with waterproofing materials

    Klovas, A.; Dauksys, M.; Ciuprovaite, G.

    2015-03-01

    Present research lays emphasis on the problem of concrete surface exposed to aggressive surrounding quality. The test was conducted with concrete surfaces coated with different waterproofing materials exposed in solution of 3 % of sodium sulphate. Research was performed according to LST EN 1338:2003 standard requirements. Technological properties of concrete mixture as well as physical-mechanical properties of formed concrete specimens were established. The resistance of concrete to freezing - thawing cycles was prognosticated according to the porosity parameters established by the kinetic of water absorption. Five different waterproofing materials (coatings) such as liquid bitumen-rubber based, elastic fiber-strengthened, silane-siloxane based emulsion, mineral binder based and liquid rubber (caoutchouc) based coatings were used. Losses by mass of coating materials and specimens surface fractures were calculated based on the results of frost resistance test. Open code program "ImageJ" was used for visual analysis of concrete specimens. Based on the results, aggressive surrounding did not influence specimens coated with elastic, fibre-strengthened, mineral materials. On the other hand, specimens coated with liquid rubber (caoutchouc) based material were greatly influenced by aggressive surrounding. The biggest losses of specimen surface concrete (fractures) were obtained with silane-siloxane based emulsion coating. Generally, specimens coated with waterproofing materials were less influenced by aggressive surrounding compared with those without.

  13. Wellhead anti-frost technology using deep mine geothermal energy

    Guo Pingye; He Manchao; Yang Qin; Chen Chen

    2011-01-01

    The auxiliary shaft is an important location for coal mine heating in the winter,where the main purpose of heating is to prevent icing of the shaft.Wellhead heating requires characteristics of openness,no-noise and big heat loads.The original coal-fired boiler heating mode causes significant waste of energy and environmental pollution due to the low efficiency of the heat exchange.Therefore,to solve these problems,we will use deep mine geothermal energy to heat the wellhead by making full use of its negative pressure field and design a low-temperature water and fan-free heating system.Through numerical calculations we will simulate temperature fields,pressure fields and velocity fields under different air supply temperatures,as well as different air supply outlet locations and varying number of radiators in the wellhead room of a new auxiliary shaft to find the proper layout and number of radiators that meet wellhead anti-frost requirements from our simulation results,in order to provide guidelines for a practical engineering design.Tests on the Zhangshuanglou auxiliary shaft wellhead shows good,look promising and appear to resolve successfully the problem of high energy consumption and high pollution of wellhead heating by a coal-fired boiler.

  14. 南方果树春季冻灾罕例调查%Investigation of rarely happened frost-damage to southern fruit in spring

    李健; 谢文龙; 施清; 徐锦斌; 罗应贵; 邱发春; 陈惠

    2011-01-01

    On March 10, 2010, fruit trees in northwestern Fujian were hit by a late spring frost with an unusual severity. The frost affected the regions north of Jiufeng Mountain (N27°, E118°50′) in eastern Fujian, Daiyun Mountain (N25°40', E118°10′) in central Fujian, and Boping Ridge in western Fujian (N24°50′, E117°10′) to varying degrees. Fruit trees damaged by the frost included two variants in 24 species, 18 genera, and seven families, such as orange, pear, peach, plum, apple and persimmon, and their yearly output dropped by about ene-fourth. An analysis of the inclement weather condition shows that the frost bite of the fruit trees was the result of two climatic factors: First, in the early spring in February, the temperature was 2.5 ℃ higher than usual,which had a recurrence rate of 8.5 years (51/6); as a result, the phenological period of the fruit trees began about 15 days early.Second, the frost, which hit on March 10, was l0 days behind the local average ending date of frost, which normally falls on March 1, and the extreme minimum temperature bad a recurrence rate of not less than 51/1 in early March; consequently, the flowering period or spring twig period of various fruit trees coincided with the late frost, resulting in extensive damage. No similar frost damage is found in the historical records on fruit trees in Fujian. An investigation in the wake of the damage shows that, in southern China,post-frost trimming in spring can be carried out after dead shoot tissues have become apparent. For vine gapes and kiwi fruits, to avoid bleeding, trimming should not be performed until after new buds are seen on the young shoots at the lower end of the vine a couple of days after the frost. As soil and water temperatures in spring have risen considerably, in the event of a radiation frost, fruit trees can be fumigated, sprinkled with water or covered up to prevent damage by frost.%2010年3月10日福建西北部果树生产遭受罕见的春季

  15. [Comparison of red edge parameters of winter wheat canopy under late frost stress].

    Wu, Yong-feng; Hu, Xin; Lü, Guo-hua; Ren, De-chao; Jiang, Wei-guo; Song, Ji-qing

    2014-08-01

    In the present study, late frost experiments were implemented under a range of subfreezing temperatures (-1 - -9 degrees C) by using a field movable climate chamber (FMCC) and a cold climate chamber, respectively. Based on the spectra of winter wheat canopy measured at noon on the first day after the frost experiments, red edge parameters REP, Dr, SDr, Dr(min), Dr/Dr(min) and Dr/SDr were extracted using maximum first derivative spectrum method (FD), linear four-point interpolation method (FPI), polynomial fitting method (POLY), inverted Gaussian fitting method (IG) and linear extrapolation technique (LE), respectively. The capacity of the red edge parameters to detect late frost stress was explicated from the aspects of the early, sensitivity and stability through correlation analysis, linear regression modeling and fluctuation analysis. The result indicates that except for REP calculated from FPI and IG method in Experiment 1, REP from the other methods was correlated with frost temperatures (P < 0.05). Thereinto, significant levels (P) of POLY and LE methods all reached 0.01. Except for POLY method in Experiment 2, Dr/SDr from the other methods were all significantly correlated with frost temperatures (P < 0.01). REP showed a trend to shift to short-wave band with decreasing temperatures. The lower the temperature, the more obvious the trend is. Of all the REP, REP calculated by LE method had the highest correlation with frost temperatures which indicated that LE method is the best for REP extraction. In Experiment 1 and 2, only Dr(min) and Dr/Dr(min), calculated by FD method simultaneously achieved the requirements for the early (their correlations with frost temperatures showed a significant level P < 0.01), sensitivity (abso- lute value of the slope of fluctuation coefficient is greater than 2.0) and stability (their correlations with frost temperatures al- ways keep a consistent direction). Dr/SDr calculated from FD and IG methods always had a low sensitivity

  16. A moving boundary problem derived from heat and water transfer processes in frozen and thawed soils and its numerical simulation

    XIE ZhengHui; SONG LiYe; FENG XiaoBing

    2008-01-01

    The seasonal change in depths of the frozen and thawed soils within their active layer is reduced to a moving boundary problem, which describes the dynamics of the total ice content using an independent mass balance equation and treats the soil frost/thaw depths as moving (sharp) interfaces governed by some Stefan-type moving boundary conditions, and hence simultaneously describes the liquid water and solid ice states as well as the positions of the frost/thaw depths in soil. An adaptive mesh method for the moving boundary problem is adopted to solve the relevant equations and to determine frost/thaw depths, water content and temperature distribution. A series of sensitivity experiments by the numerical model under the periodic sinusoidal upper boundary condition for temperature are conducted to validate the model, and to investigate the effects of the model soil thickness,ground surface temperature, annual amplitude of ground surface temperature and thermal conductivity on frost/thaw depths and soil temperature. The simulated frost/thaw depths by the model with a periodical change of the upper boundary condition have the same period as that of the upper boundary condition, which shows that it can simulate the frost/thaw depths reasonably for a periodical forcing.

  17. Evidence for warmer event from quartz grains in the soil of Grove Mountains, East Antarctica

    Yan Xin; Li Xiaoli; Liu Xiaohan; Zhang Ru-fan

    2005-01-01

    The cold desert soil has been discovered at first time in southern ridgeof Mount Harding, Grove Mountains of interior East Antarctica Ice Sheet. Based on the micro structural observation, dominant characteristics of quartz grains include: distinct surface stria and fractures, and clean features of frost action at both of crystal margins and micro crannies of quartz grains. These features show a pedogenesis environment of few water, short transportation and frost action, revealing a warmer climatic event existed in this region.

  18. Likely frost events at Gale crater: Analysis from MSL/REMS measurements

    Martínez, G. M.; Fischer, E.; Rennó, N. O.; Sebastián, E.; Kemppinen, O.; Bridges, N.; Borlina, C. S.; Meslin, P.-Y.; Genzer, M.; Harri, A.-H.; Vicente-Retortillo, A.; Ramos, M.; de la Torre Juárez, M.; Gómez, F.; Gómez-Elvira, J.

    2016-12-01

    We provide indirect evidence for the formation of frost at the surface of Gale crater by analyzing the highest confidence data from simultaneous measurements of relative humidity and ground temperature during the first 1000 sols of the Mars Science Laboratory (MSL) mission. We find that except for sol 44, frost events could have occurred only between sols 400 and 710, corresponding to the most humid and coldest time of the year (from early fall to late winter). In particular, measurements at Dingo Gap during sols 529-535, at an unnamed place during sols 554-560, at Kimberley during sols 609-617 and at an unnamed place during sols 673-676 showed the largest likelihood of the occurrence of frost events. At these four locations, the terrain is composed of fine-grained and loosely packed material with thermal inertia values of ∼200 SI units, much lower than the 365 ± 50 SI units value found at the landing ellipse. This is important because terrains with exceptionally low thermal inertia favor the formation of frost by lowering minimum daily ground temperatures. An order-of-magnitude calculation to determine the thickness of the frost layer at these four locations results in values of tenths of μm, while the precipitable water content is a few pr-μm. Therefore, surface frost events can have important implications for the local water cycle at Gale crater. In addition, frost is the most likely type of water that can be temporarily found in bulk amounts on the surface of Mars at low latitudes and therefore can cause weathering, influencing the geology of Gale crater.

  19. The barley Frost resistance-H2 locus.

    Pasquariello, Marianna; Barabaschi, Delfina; Himmelbach, Axel; Steuernagel, Burkhard; Ariyadasa, Ruvini; Stein, Nils; Gandolfi, Francesco; Tenedini, Elena; Bernardis, Isabella; Tagliafico, Enrico; Pecchioni, Nicola; Francia, Enrico

    2014-03-01

    Frost resistance-H2 (Fr-H2) is a major QTL affecting freezing tolerance in barley, yet its molecular basis is still not clearly understood. To gain a better insight into the structural characterization of the locus, a high-resolution linkage map developed from the Nure × Tremois cross was initially implemented to map 13 loci which divided the 0.602 cM total genetic distance into ten recombination segments. A PCR-based screening was then applied to identify positive bacterial artificial chromosome (BAC) clones from two genomic libraries of the reference genotype Morex. Twenty-six overlapping BACs from the integrated physical-genetic map were 454 sequenced. Reads assembled in contigs were subsequently ordered, aligned and manually curated in 42 scaffolds. In a total of 1.47 Mbp, 58 protein-coding sequences were identified, 33 of which classified according to similarity with sequences in public databases. As three complete barley C-repeat Binding Factors (HvCBF) genes were newly identified, the locus contained13 full-length HvCBFs, four Related to AP2 Triticeae (RAPT) genes, and at least five CBF pseudogenes. The final overall assembly of Fr-H2 includes more than 90 % of target region: all genes were identified along the locus, and a general survey of Repetitive Elements obtained. We believe that this gold-standard sequence for the Morex Fr-H2 will be a useful genomic tool for structural and evolutionary comparisons with Fr-H2 in winter-hardy cultivars along with Fr-2 of other Triticeae crops.

  20. 季节冻土区刚柔混合衬砌梯形渠道冻胀机理试验%Test for frost heaving damage mechanism of rigid-soften composite trapezoidal canal in seasonally frozen ground region

    姜海波; 田艳

    2015-01-01

    输水渠道冻胀破坏是寒冷地区渠道破坏的主要表现。为了探明刚柔混合衬砌渠道的冻胀机理,分析复合衬砌渠道的冻胀变形规律和冻胀过程中的水分变化规律,以及柔性复合土工膜的变形特征,该研究借助季节冻融条件下刚柔混合衬砌梯形渠道的原型观测成果,分析了刚柔混合衬砌渠道的最低地温变化规律、冻深变化规律和冻胀量与冻胀力的变化规律,重点研究了冻融条件下渠基土壤的水分迁移规律,以及复合土工膜的变形特征和强度变化。结果显示:刚柔混合衬砌渠道的冻胀变形最大值位于渠底和阴坡1/3处,最大冻胀量为11.2和13.1 cm,衬砌结构向上隆起。冻结期,渠基土壤0~60 cm深度范围内含水率随深度增加而增大,>60~120 cm深度范围内的含水率随深度增大而逐渐减小。水分迁移最大值发生在渠道底部,迁移率为13.2%。经过一个冻融周期的循环,复合土工膜的强度和变形量仍然保持在90%以上,强度和变形损失值较小,可充分发挥复合土工膜防渗抗冻胀和适应变形的特性。该研究为刚柔混合衬砌渠道的设计、推广应用提供了理论依据。%In the area of seasonal frozen soil in North China and Northwest, there exists massive and serious frost-heave damage of concrete lining canal. Frost-heave damage is the main reason for the channels. In this paper, the prototype experiments were conducted in order to explore the frost-heave mechanism of rigid-soften composite canal in the irrigation area of high-cold region. The frost deformation the soil moisture variation of the trapezoidal canal lined with concrete and composite geo-membrane, and especially the rules of frost-heave deformation and the deformation features of composite geo-membrane were further systematically studied. The experiment followed the leading thought of suiting and reducing the frost-heave destruction

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

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

    2014-10-01

    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.

  2. Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event

    M. K. Pihlatie

    2010-05-01

    Full Text Available Fluxes of greenhouse gases (GHG carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O were measured during a two month campaign at a drained peatland forest in Finland by the eddy covariance (EC technique (CO2 and N2O, and automatic and manual chambers (CO2, CH4 and N2O. In addition, GHG concentrations and soil parameters (mineral nitrogen, temperature, moisture content in the peat profile were measured. The aim of the measurement campaign was to quantify the GHG fluxes during freezing and thawing of the top-soil, a time period with potentially high GHG fluxes, and to compare different flux measurement methods. The forest was a net CO2 sink during the two months and the fluxes of CO2 dominated the GHG exchange. The peat soil was a small sink of atmospheric CH4 and a small source of N2O. Both CH4 oxidation and N2O production took place in the top-soil whereas CH4 was produced in the deeper layers of the peat, which were unfrozen throughout the measurement period. During the frost-thaw events of the litter layer distinct peaks in CO2 and N2O emissions were observed. The CO2 peak followed tightly the increase in soil temperature, whereas the N2O peak occurred with a delay after the thawing of the litter layer. CH4 fluxes did not respond to the thawing of the peat soil. The CO2 and N2O emission peaks were not captured by the manual chambers and hence we conclude that high time-resolution measurements with automatic chambers or EC are necessary to quantify fluxes during peak emission periods. Sub-canopy EC measurements and chamber-based fluxes of CO2 and N2O were comparable, although the fluxes of N2O measured by EC were close to the detection limit of the system. We conclude

  3. Keeping a surface ice/frost free with electro-conducting water-repellent coatings

    Das, Arindam; Kapatral, Shreyas; Megaridis, Constantine M.

    2013-11-01

    Ice/frost formation on aircraft, wind turbines, power grids, marine vessels, telecommunication devices, etc. has propelled scientific research on surfaces that facilitate the removal of the water solid phase or retard its formation. Superhydrophobic, self-cleaning surfaces have been investigated recently (Jung et al., Langmuir 2011) for their passive anti-icing properties. Although superhydrophobic surfaces have been shown to delay the onset of frosting and icing, they cannot prevent it entirely. Hence active deicing/defrosting approaches are required to keep surfaces free of ice/frost. Defrosting experiments have been carried out on glass substrates coated with textured polymeric nanocomposite films of different surface wettability, porosity and roughness. A strong influence of these parameters on condensation, condensation frosting and defrosting was observed. The coatings are electro-conducting, thus allowing skin heating at the interface between ice and the substrate. Sustained ice- and frost-free operation is demonstrated at substrate temperatures well below the freezing point and in humid ambient atmospheres. Supported by NSF Grant CBET-1066426.

  4. Short communication. Harvest time in hedgerow Arbequina olive orchards in areas with early frosts

    Gracia, P.; Sanchez-Gimeno, A. C.; Benito, M.; Oria, R.; Lasa, J. M.

    2012-11-01

    The shortening of harvest time attained in hedgerow olive (Olea europaea L.) orchards represents an advantage for the adoption of this cropping system in areas that are prone to suffer frost during the harvest period. To establish an optimal harvesting window, we carried out a study of the fruit ripening process on a hedgerow orchard of Arbequina olive trees, located in Zaragoza (Spain). From 2007 to 2009, oil accumulation on the fruit (% of dry weight) and oil yield (grams of oil per 100 fruits) were monitored, from early September to late November. Over the three years both variables peaked around November 15th, indicating that Arbequina reached full ripening earlier than has been reported previously for this variety. In two of the three seasons the orchard suffered several frosts during November. Long term climatic data from this area indicated that the risk of early frosts (< -2 degree centigrade) increases as November progresses with a high risk after November 20{sup t}h. In conclusion, the optimal harvesting period for Arbequina in this area should not extend beyond November 20{sup t}h. A rapid harvesting before this date is advisable to avoid the risk of damage caused by early frost in Zaragoza. Hedgerow planting provides an additional advantage in frost-prone areas, because mechanization of operations permits a short harvest period, easier to fit into the optimal harvesting window. (Author) 20 refs.

  5. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

    Xu, Li [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Now at Department of Earth System Science, University of California, Irvine California USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Burrows, Susannah M. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-09-23

    In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.

  6. Sprayable superhydrophobic nano-chains coating with continuous self-jumping of dew and melting frost.

    Wang, Shanlin; Zhang, Wenwen; Yu, Xinquan; Liang, Caihua; Zhang, Youfa

    2017-01-11

    Spontaneous movement of condensed matter provides a new insight to efficiently improve condensation heat transfer on superhydrophobic surface. However, very few reports have shown the jumping behaviors on the sprayable superhydrophobic coatings. Here, we developed a sprayable silica nano-porous coating assembled by fluorinated nano-chains to survey the condensates' dynamics. The dewdrops were continuously removed by self- and/or trigger-propelling motion due to abundant nano-pores from random multilayer stacking of nano-chains. In comparison, the dewdrops just could be slipped under the gravity effect on lack of nano-pores coatings stacked by silica nano-spheres and nano-aggregates. More interestingly, the spontaneous jumping effect also occurred on micro-scale frost crystals under the defrosting process on nano-chains coating surfaces. Different from self-jumping of dewdrops motion, the propelling force of frost crystals were provided by a sudden increase of the pressure under the frost crystal.

  7. Performance tests of air source heat pumps under frosting conditions. Quality of results

    Fahlen, P.

    This report focuses on the analysis of uncertainties in research regarding air-source heat pumps. The principles recommended by the Western European Calibration Conference (WECC) are applied and the generated information is condensed in the form of uncertainty budgets. The ensuring discussion, and the Measurement Assurance Program that was applied during the research work are also relevant to general testing of cooling coils, e.g. for air source heat pumps. The general conclusion of the analysis is that the method of determining frost mass by continuous weighing and frost density by inference from pressure drop considerations, which is presented in the report, has the potential to produce results with an accuracy on a par with the best previously used techniques to investigate frosting and defrosting phenomena. Furthermore, the methodology has the distinct advantage of yielding online measuring possibilities and being much less time consuming than traditional techniques.

  8. Suscetibilidade magnética do horizonte B de solos do Estado do Paraná Magnetic susceptibility of B horizon of soils in the State of Paraná

    Alceu Rodrigues da Silva

    2010-04-01

    Full Text Available Os minerais ferrimagnéticos maghemita (γFe2O3 e magnetita (Fe3O4 possuem alta relação com a disponibilidade de cátions metálicos e com a capacidade do solo em adsorver ânions como o fosfato. Uma percentagem expressiva dos solos brasileiros apresenta magnetização espontânea. No Estado do Paraná essa área corresponde a aproximadamente 50 %. A determinação da suscetibilidade magnética por unidade de massa (ΧBF é o método mais simples de identificar a presença e quantificar esses minerais nos solos. A BF é uma técnica rápida, barata, não destrutiva e de boa reprodutibilidade, que pode ser utilizada como critério nos estudos pedogenéticos em que os minerais ferrimagnéticos estão presentes. O objetivo deste trabalho foi verificar a influência do material de origem nos valores de ΧBF da terra fina seca ao ar (TFSA de amostras do horizonte B de solos do Paraná. As amostras foram coletadas em todo o Estado, num total de 45 pontos. Na TFSA foram determinados os valores de BF e da porcentagem da frequência dependente da suscetibilidade magnética (ΧFD. Os valores de suscetibilidade magnética dos solos formados sobre rochas eruptivas básicas foram significativamente maiores (1.000 a 7.800 x 10-8 m³ kg-1 que os encontrados em solos formados sobre rochas metamórficas e sedimentares (menores do que 500 x 10-8 m³ kg-1, demonstrando a influência do material de origem na presença de minerais ferrimagnéticos. Os valores de ΧFD indicaram a presenca de partículas superparamagnéticas (maghemita na maioria dos solos paranaenses.The ferrimagnetic minerals maghemite (γFe2O3 are closely related with metal availability and P adsorption capacity. Magnetization is spontaneous in a significant percentage of Brazilian soils. In the State of Paraná (Brazil this area represents up to 50 %. The determination of the mass-specific magnetic susceptibility (ΧBF is the simplest method of identification and quantification of ferrimagnetic

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

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

    2012-11-01

    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.

  10. Anti-frost heave effect of lining channel with concrete composite insulation based on TCR principle%基于TCR传热原理的混凝土复合保温衬砌渠道防冻胀效果研究

    郭瑞; 王正中; 牛永红; 刘铨鸿; 王羿

    2015-01-01

    and displacement field were calculated and analyzed by the thermo-mechanical coupling field finite element method. The composite thermal-mechanical simulation was used to compare the new one and the ordinary benzene insulation board by means of the finite element software ABAQUS. Simulation results showed that for the temperature field, the zero degree isotherm in the composite insulation lining channel soil was higher than that in the channel with EPS insulation board, and the maximum difference was nearly 20.3 cm. The concrete composite insulation lining could not only block the conduction of the negative temperature outside and improve the temperature of the soil, but also reduce the freezing depth of the soil and improve the anti-frost heaving ability effectively. For the displacement field, the distribution of the frost heaving amounts in the channel with EPS insulation board was even. Among these models, the frost heaving amounts of the channel with the composite insulation lining could be reduced by 71%, 46% and 40% respectively compared to the prototype channel and the other 2 models, which showed that the anti-frost heave effect was obvious. Similarly, the frost heaving force that functioned on canal lining was analyzed and compared, mainly including normal frost heaving force and tangential freezing force. In the stress analysis of flexible EPS insulation board composite insulation lining, the friction between concrete lining plate and foundation soil was reduced as the concrete lining did not contact with the soil. The EPS board between concrete lining and foundation had certain flexibility, and when the frost heaving of canal foundation occurred, it would release stress and distribute channel lining stress evenly. Compared with the prototype channel, the distribution of normal and tangential freezing force of the concrete composite insulation lining channel tended to be uniform, which improved the stress of the channel lining greatly. However, in terms of

  11. Soil proteomics

    Oonk, S.; Cappellini, Enrico; Collins, M.J.

    2012-01-01

    In this work, two sets of experiments were carried out to assess the potential of soil proteomics for archaeological site interpretation. First, we examined the effects of various protein isolation reagents and soil constituents on peptide mass fingerprinting (PMF) of soil-like materials spiked...... with bovine serum albumin (BSA). In a subsequent case study, we assessed the relative age of soils from an ancient clay floor of a Roman farmhouse using amino acid racemization and then applied MALDI-TOF-MS-MS to detect and identify biomarkers for human occupation. The results from the first experiments......) are more susceptible to isolation than other regions and this suggest that soil proteins can be only partly isolated. Soil-protein interactions were also found to inhibit tryptic cleavage of BSA, resulting in an enhanced specificity of BSA peptides. Our results further stress the importance of multiple...

  12. Robert Frost's "The road not taken", Childhood, psychoanalytic symbolism, and creativity.

    Glenn, J

    2001-01-01

    Robert Frost, often regarded as a folksy farmer-poet, was also a more profound, even terrifying, creator. His poem "The Road Not Taken" reveals his delight in multiple meanings, his ambivalence, and his penchant for misleading his readers. He denied that the poem proclaimed his striving for the unconventional and asserted that it was meant to tease his friend Edward Thomas for his compulsive indecisiveness. This essay also notes the unconscious meanings of the poem, including Frost's reactions to losing his close friend, his own indecisiveness, his conflict between heterosexual and homosexual object choices, his need for a "secret sharer," and his attachments.

  13. Performance Evaluation Of Peripheral-Finned Tube Evaporators Under Frosting Conditions

    2016-01-01

    The peripheral finned-tube (PFT) is a novel air-side geometry for compact heat exchangers. Previous studies (Pussoli et al., Int. J. Heat Mass Transfer 55, 2835–2843, 2012) dealt with the evaluation of the thermal-hydraulic performance of the PFT geometry under dry conditions (i.e., no frost or condensate formation on the air side). The present study is focused on quantifying the thermal-hydraulic perfomance of the PFT geometry under frosting conditions. PFT evaporators were tested in a clo...

  14. Moving Frost Hardy Genes From Wild to Cultivated Potatoes. Use of Precise Screening Tools to Make Real Progress

    The common cultivated species Solanum tubrosum is frost sensitive and is killed at temperatures below -2.5°C. It has been estimated that by increasing frost hardiness by 1–2 C one can expect an increase in potato yield by 26 to 40% in the Altiplano (Peru and Bolivia) covering 63,000 ha. of potatoes....

  15. Puerto Rico Soil Erodibility (Kffact)

    National Oceanic and Atmospheric Administration, Department of Commerce — Puerto Rico soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  16. 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

    Jellín del Carmen Pavón T

    2010-01-01

    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.

  17. Electoral Susceptibility

    Levine, G C; Cerise, J E

    2012-01-01

    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...

  18. Development and Validation of the Frost Multidimensional Perfectionism Scale--Brief

    Burgess, Alexandra M.; Frost, Randy O.; DiBartolo, Patricia Marten

    2016-01-01

    Twenty-five years ago, one of the first empirically validated measures of perfectionism, the Frost et al. Multidimensional Perfectionism Scale (F-MPS) was published. Since that time, psychometric studies of the original F-MPS have provided a plethora of evidence to support the potential development of a shorter yet still psychometrically robust…

  19. Flagstaff Robotic Survey Telescope (FRoST): Rapid Response for NEOs

    Avner, Louis Daniel; Trilling, David E.; Dunham, Edward W.

    2016-10-01

    The Flagstaff Robotic Survey Telescope (FRoST) is a robotic 0.6m Schmidt telescope that will be used for instant follow-up observations of newly discovered Near Earth Objects (NEOs). Here, we present the progress being made on FRoST as well as the remaining tasks until the telescope is fully operational. With more than one thousand NEOs being found yearly, more telescopes are needed to carry out follow-up observations. Most NEOs are found at their peak brightness, meaning that these observations need to happen quickly before they fade. By using the Catalina Sky Survey Queue Manager, FRoST will be able to accept interruptions during the night and prioritize observations automatically, allowing instant follow-up observations. FRoST will help refine the orbit of these newly discovered objects while providing optical colors. We will ingest information from the NEOCP and JPL's Scout program at five minute intervals and observe newly discovered targets robotically, process the data automatically, and autonomously generate astrometry and colors. We estimate that will we provide essentially 100% recovery of objects brighter than V~20. This work was supported by the NSF MRI program as well as by NAU and Lowell Observatory.

  20. Superabsorbent Polymers as a Means of Improving Frost Resistance of Concrete

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede; Laustsen, Sara

    2015-01-01

    Superabsorbent polymer (SAP) was introduced in cementitious materials about 15 years ago. Since then, several studies on the frost resistance of concrete with SAP have been published. However, an up-to-date review across the different studies is missing. This paper presented a literature review...

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

    Sathi Veerraghava Reddy

    2014-06-01

    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.

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

    2008-01-01

    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.

  3. Frost flower chemical signature in winter snow on Vestfonna ice cap, Nordaustlandet, Svalbard

    E. Beaudon

    2009-07-01

    Full Text Available The chemistry of snow and ice cores from Svalbard is influenced by variations in local sea ice margin and distance to open water. Snow pits sampled at two summits of Vestfonna ice cap (Nordaustlandet, Svalbard, exhibit spatially heterogeneous soluble ions concentrations despite similar accumulation rates, reflecting the importance of small-scale weather patterns on this island ice cap. The snow pack on the western summit shows higher average values of marine ions and a winter snow layer that is relatively depleted in sulphate. One part of the winter snow pack exhibits a [SO42-/Na+] ratio reduced by two thirds compared with its ratio in sea water. This low sulphate content in winter snow is interpreted as the signature of frost flowers, which are formed on young sea ice when offshore winds predominate. Frost flowers have been described as the dominant source of sea salt to aerosol and precipitation in ice cores in coastal Antarctica but this is the first time their chemical signal has been described in the Arctic. The eastern summit does not show any frost flower signature and we interpret the unusually dynamic ice transport and rapid formation of thin ice on the Hinlopen Strait as the source of the frost flowers.

  4. On the need for data for the verification of service life models for frost damage

    Geiker, Mette Rica; Engelund, Sven

    1999-01-01

    The purpose of this paper is to draw the attention to the need for the verification of service life models for frost attack on concrete and the collection of relevant data. To illustrate the type of data needed the paper presents models for internal freeze/thaw damage (internal cracking including...

  5. Effect of Fly Ash on Frost-Resistance and Chloride Ions Diffusion Properties of Marine Concrete

    YANG Wen-wu; QIAN Jue-shi; ZHANG Yi-ying

    2009-01-01

    It is necessary to pay more attention to the durability of concrete undergoing freeze-thaw cycles and seawater attack simultaneously.Investigated are the effects of water-binder ratio,fly ash (FA) contents and air-entraining agent on resistance to frost and chloride diffusion of marine concrete blended with FA in natural seawater.The results show that fly ash does not improve the frost resistance of concrete but can improve its resistance to chloride diffusion by addition of less than 30%.The resistance to frost and chloride diffusion of FA concrete can be improved with the decrease of water-binder ratio,and FA may improve both of them simultaneously only being mixed with air-entraining agent.A ratio (named as R) of the frost-resisting durability factor to chloride diffusion coefficient can be used to evaluate the durability of marine concrete.Scanning electron microscope (SEM) analyses are consistent with the evaluations by the value of R.

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

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

    2014-03-01

    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.

  7. Development of a protocol for frost-tolerance evaluation in rapeseed/canola (Brassica napus L.)

    Danielle Fiebelkorn; Mukhlesur Rahman

    2016-01-01

    Spring frost can severely damage or even kill rapeseed/canola (Brassica napus L.) seedlings. A protocol for large scale screening of rapeseed germplasm under frost-simulating conditions has not yet been developed. Accordingly, the present study was conducted to develop a protocol for screening rapeseed germplasm under artificial frost-simulation conditions in a plant growth chamber and in a greenhouse. Nine rapeseed varieties, including three commercial hybrids, three spring types, and three winter types were used. Cold acclimation at 4 °C was applied for 0, 7, or 14 days to two-week old seedlings. The seedlings were treated with four freezing temperatures (−4 °C, −8 °C, −12 °C, and −16 °C). The length of the freezing period was 16 h, including the ramping of temperature down from 4 °C and up from the respective freezing temperature to 4 °C. Plants were allowed to recover at 4 °C for 24 h before they were moved back to the greenhouse. Frost damage was scored on a 0–5 scale, where 0 denotes completely dead and 5 denotes no damage. Seedling survival from the freezing treatment increased from the non-acclimation to the cold acclimation treatment. However, no significant differences (P<0.05) were found between 7 and 14 days of acclimation. Frost treatment at −4 °C resulted in significant differences in seedling damage relative to the other three temperatures, with the −16 °C treatment resulting in the highest overall seedling damage. Significant differences were found between the spring type and the other two types (hybrid and winter). However, no significant differences were found between the hybrid and winter types. The suggested protocol for the assessment of frost tolerance is acclimation of two-week old seedlings for 7 days at 4 °C followed by frost treatment at−4 °C for 16 h.

  8. Increased Susceptibility to Aphids of Flowering Wheat Plants Exposed to Low Temperatures.

    Lacoste, C; Nansen, C; Thompson, S; Moir-Barnetson, L; Mian, A; McNee, M; Flower, K C

    2015-06-01

    Frost is known to directly affect flowering wheat plants (Triticum aestivum L.) and lead to reduced grain yield. Additionally, it may increase wheat susceptibility to economically important pests, such as aphids (Hemiptera: Aphididae). Wheat plants at flowering stage were exposed to one of the three temperature treatments: ambient (11-12°C), 0°C, and -3°C for 60 min. Preference (3-choice) and performance (no-choice) bioassays with aphids (Rhopalosiphum padi L.) were conducted 1, 3, 6, and 12 d after temperature treatments to assess effects of temperature-induced stress over time. As an initial feasibility study of using remote sensing technologies to detect frost-induced stress in flowering wheat plants, hyperspectral imaging data were acquired from wheat plants used in preference bioassays. Element analysis of wheat plants was included to determine the effect of temperature-induced stress on the nutritional composition of flowering wheat plants. The results from this study support the following cause-effect scenario: a 60-min exposure to low temperatures caused a significant decrease in potassium and copper content of wheat plants 6 d after temperature exposure, and it coincided with a marked increase in preference by aphids of wheat plants. The preference exhibited by aphids correlated positively with performance of aphids, so the preference-performance hypothesis was confirmed and possibly driven by potassium and copper content of wheat plants. In addition, we demonstrated that hyperspectral imaging data can be used to detect frost-induced susceptibility to aphid infestation in flowering wheat plants. These findings justify further research into airborne remote sensing of frost-induced stress and the possible secondary effects on crop susceptibility to arthropod pests.

  9. Frost Damage Detection in Sugarcane Crop Using Modis Images and Srtm Data

    Rudorff, B.; Alves de Aguiar, D.; Adami, M.

    2011-12-01

    Brazil is the largest world producer of sugarcane which is used to produce almost equal proportions of either sugar (food) or ethanol (biofuel). In recent years sugarcane crop production has increased fast to meet the growing market demand for sugar and ethanol. This increase has been mainly due to expansion in crop area, but sugarcane production is also subjected to several factors that influence both the agricultural crop yield (tons of stalks/ha) and the industrial yield (kg of sugar/ton of stalks). Sugarcane is a semi-perennial crop that experiences major growth during spring and summer seasons with large demands for water and high temperatures to produce good stalk formation (crop yield). The harvest is performed mainly during fall and winter seasons when water availability and temperature should be low in order to accumulate sucrose in the stalks (industrial yield). These favorable climatic conditions for sugarcane crop are found in several regions in Brazil, particularly in São Paulo state, which is the major sugarcane producer in Brazil being responsible for almost 60% of its production. Despite the favorable climate in São Paulo state there is a certain probability of frost occurrence from time to time that has a negative impact on sugarcane crop, particularly on industrial yield, reducing the amount of sugar in the stalks; having consequences on price increase and product shortage. To evaluate the impact of frost on sugarcane crop, in the field, on a state level, is not a trivial task; however, this information is relevant due to its direct impact on the consumer market. Remote sensing images allow a synoptic view and present great potential to monitor large sugarcane plantations as has been done since 2003 in São Paulo state by the Canasat Project with Landsat type images (http://www.dsr.inpe.br/laf/canasat/en/). Images acquired from sensors with high temporal resolution such as MODIS (Moderate-Resolution Imaging Spectroradiometer) present the

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

    T. Thornberry

    2010-08-01

    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.

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

    T. Thornberry

    2011-02-01

    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.

  12. 1960-2011年新疆初终霜日及无霜期的变化特征%Changes of the First Frost Dates, Last Frost Dates and Duration of Frost-free Season in Xinjiang during the Period of 1960-2011

    潘淑坤; 张明军; 汪宝龙; 马雪守

    2013-01-01

    In this paper,the first frost date,last frost date and duration of frost-free season as well as their change trends were analyzed using the linear trend estimation,anomaly analysis and five-year moving average based on the daily minimum temperature data observed by 51 meteorological stations in Xinjiang during the period from 1960 to 2011.The results showed that the average first frost date was postponed by 11 days,the average last frost date was moved up by 7 days,and the duration of frost-free season was extended by 17 days.The first frost dates,last frost dates and durations of frost-free season in north Xinjiang,south Xinjiang and the Tianshan Mountains were consistent with those in whole Xinjiang,but the change extent was not different.Their variation was the most significant in the Tianshan Mountains,and then in north Xinjiang and south Xinjiang.The first frost date,last frost date and duration of frost-free season were closely related to the geographical and temperature factors.The first frost date occurred earlier,the last frost date later,and the duration of frost-free season became shorter along with the increase of latitude and altitude.Along with the temperature increasing,however,the first frost date became later,the last frost date earlier,and the duration of frost-free season longer.The effect of minimum temperature was higher than that of average temperature and maximum temperature.%利用1960-2011年新疆51个地面气象站逐日最低气温观测资料,运用线性趋势、距平分析、5a滑动平均等方法,分析了初、终霜日和无霜期的基本特征及其变化趋势.结果表明:新疆初霜日推迟11d,终霜日提前7d,无霜期延长17 d.北疆、南疆和天山初、终霜日及无霜期与新疆整体变化趋势一致,但变化程度不同.天山地区变化最显著,其次是北疆,最后是南疆.初、终霜日的出现和无霜期的长短与地理因素和温度密切相关,随着海拔的升高,纬度的增加,初霜

  13. Experimental investigations of freezing soils at ground conditions of Astana, Kazakhstan

    Zhussupbekov Askar; Shakhmov Zhanbolat

    2015-01-01

    Kazakhstan regions is seasonal climatic with transient freezing of soil ground during the winter. Roadbed integrity is important to resist the sustained load transmitted by traffic on the road surface. Freezing of soil ground could significantly influence roadbed integrity in the seasonal freezing climate of Kazakhstan. The proper determination magnitude of frost heave and heaving pressure by the influence of freezing temperatures during the winter season are necessary for design and construction of highways. Thus, experimental tests were conducted on specimens obtained from Astana (Kazakhstan) to determine the freezing pressure and magnitude of frost heaving.

  14. Weather, snow load frost depth, Published in 2009, 1:24000 (1in=2000ft) scale, Washington County.

    NSGIC GIS Inventory (aka Ramona) — This Weather dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2009. It is described as 'snow load frost...

  15. Frost Monitoring and Forecasting Using MODIS Land Surface Temperature Data and a Numerical Weather Prediction Model Forecasts for Eastern Africa

    Kabuchanga, Eric; Flores, Africa; Malaso, Susan; Mungai, John; Sakwa, Vincent; Shaka, Ayub; Limaye, Ashutosh

    2014-01-01

    Frost is a major challenge across Eastern Africa, severely impacting agricultural farms. Frost damages have wide ranging economic implications on tea and coffee farms, which represent a major economic sector. Early monitoring and forecasting will enable farmers to take preventive actions to minimize the losses. Although clearly important, timely information on when to protect crops from freezing is relatively limited. MODIS Land Surface Temperature (LST) data, derived from NASA's Terra and Aqua satellites, and 72-hr weather forecasts from the Kenya Meteorological Service's operational Weather Research Forecast model are enabling the Regional Center for Mapping of Resources for Development (RCMRD) and the Tea Research Foundation of Kenya to provide timely information to farmers in the region. This presentation will highlight an ongoing collaboration among the Kenya Meteorological Service, RCMRD, and the Tea Research Foundation of Kenya to identify frost events and provide farmers with potential frost forecasts in Eastern Africa.

  16. 西吉县霜冻天气形势分析%Circulation Situation Analysis of Frost in Xiji County

    郑东生; 孙俊

    2014-01-01

    The weather principles and methods,the historical weather charts and routine observation in Xiji County were used to analyze and somatotype the weather patterns of spring frost and autumn frost.The result showed that the occurrence of spring frost and autumn frost had a relationship with the higher pressure ridges in Xinjiang.%应用天气学原理和方法,利用历史天气图和西吉县常规气象观测资料,对西吉县春霜冻和秋霜冻天气形势进行了分析,结果显示:西吉春、秋霜冻大多与新疆高压脊活动有关。

  17. Anti-fogging and anti-frosting behaviors of layer-by-layer assembled cellulose derivative thin film

    Shibraen, Mahmoud H. M. A.; Yagoub, Hajo; Zhang, Xuejian; Xu, Jian; Yang, Shuguang

    2016-05-01

    Two cellulose derivatives, quaternized cellulose (QC) and carboxymethyl cellulose (CMC), were layer-by-layer (LbL) assembled to prepare a thin film. QC was also LbL assembled with two synthetic polyelectrolytes, poly(acrylic acid) (PAA) and poly(styrene sulfonate) (PSS), separately. The anti-fogging and anti-frosting properties of the assembled films were studied. QC/CMC thin film exhibits anti-fogging and anti-frosting behaviors, whereas QC/PAA and QC/PSS films do not have capacity for anti-fogging and anti-frosting. The anti-fogging and anti-frosting properties of QC/CMC film are attributed to that water molecules can be quickly adsorbed into the matrix of the film. The water adsorption of QC/CMC film was illustrated by the optical thickness increment.

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

    M. Piot

    2007-04-01

    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

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

    M. Piot

    2008-05-01

    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

  20. USE OF PHASE CHANGE MATERIAL (PCM FOR FROST PREVENTION IN A MODEL GREENHOUSE

    Ahmet KÜRKLÜ

    1997-02-01

    Full Text Available In this study, the possibility of using phase change materials to prevent occurrance of frost in greenhouses during winter was investigated. The melting and freezing temperatures of the PCM were about 8 oC and 4 oC, respectively.The air temperature difference between the PCM and the control greenhouses was about 2oC on average during the day and night time, PCM greenhouse having the higher temperature at night and lower temperature during the day. Frost was prevented on 7 out of 9 occasions, though the temperature difference between the greenhouses was small for some of these days. Solar fraction stored by the PCM store was about 30 %.

  1. Influence of supermarket environmental parameters on the frosting and defrosting of vertical multideck display cabinets

    Tassou, S.A.; Datta, D.

    1999-07-01

    This paper reports on results of investigations to identify and quantify the effect of in-store environmental conditions on frost accumulation on the evaporator coils of open multideck refrigerated display cabinets. Field and environmental chamber-based tests have shown that both ambient relative humidity and temperature of a store have a significant effect on the rate of frost formation on the evaporator coils, with the effect of relative humidity being much more pronounced than the effect of temperature. In supermarkets where a fixed-time defrost control strategy is employed, it is possible that cabinets are defrosted too infrequently at high relative humidities, resulting in high product temperatures, and too frequently at low relative humidities, resulting in excessive energy consumption. Considerable opportunity exists for the application of more sophisticated defrost control strategies, both to save energy and improve temperature control.

  2. THE POTENTIAL IMPACT OF ICE-MINUS BACTERIA AS A FROST PROTECTANT IN NEW YORK TREE FRUIT PRODUCTION

    John M. Love; Lesser, William H.

    1989-01-01

    Ice-nucleating bacteria, which are known to occur naturally on many crops and have been associated with frost damage, may be subject to control with genetically engineered bacteria, dubbed "ice-minus" bacteria. Ice-minus technology is designed to depress the critical temperature at which frost damage begins by displacing the natural population of ice-nucleating organisms. A trial product has been tested in the field with strawberries. Although tests with bacteriacidal compounds have suggested...

  3. Dirac particles interacting with the improved Frost-Musulin potential within the effective mass formalism

    Tas, Ahmet; Aydogdu, Oktay; Salti, Mustafa

    2017-04-01

    We mainly investigate the dynamics of spin-1/2 particles with position-dependent mass for the improved Frost-Musulin potential under spin-pseudospin symmetry. First, we find an approximate analytical solution of the Dirac equation both for bound and scattering states under spin-pseudospin symmetry and then we see that the normalized solutions are given in terms of the Gauss hypergeometric functions. In further steps, we analyze our results numerically.

  4. Frost formation and defrost control parameters for open multideck refrigerated food display cabinets

    Tassou, S.A.; Datta, D. [Brunel Univ., Dept. of Mechanical Engineering, Uxbridge (United Kingdom); Marriott, D. [Safeway Stores plc, Hayes (United Kingdom)

    2001-04-03

    In order to achieve the required air and product temperatures in refrigerated food display cabinets, the evaporator coils, which are normally located in the base of the cabinets, operate at temperatures below the freezing point of water. The air which is circulated over the evaporator coil is cooled below its dew point and water vapour present in the air condenses and eventually freezes on the coil surface. With continuous operation of the coil, frost will accumulate on the coil surface leading to a decrease both in the air flowrate and in the overall heat transfer coefficient. In order to maintain satisfactory performance, evaporator coils are defrosted periodically. Although different defrost control strategies can be employed, for simplicity and cost considerations, defrosting in supermarket refrigeration systems is usually controlled by a pre-set time cycle. It is widely acknowledge, however, that time-based defrost may cause a number of unnecessary defrost cycles and this reduces the energy efficiency of the refrigeration systems as well as the accuracy of temperature control of the cabinets. Implementing defrost only when it is needed or on 'demand' should reduce the number of defrost cycles and lead to savings in energy and improved product quality. This paper reports on field and experimental investigations on the processes of frosting and defrosting of medium-temperature display cabinet evaporator coils. The results show that for medium-temperature refrigeration applications where the environment temperature is kept reasonably constant, the store humidity is the primary parameter influencing the rate of frost formation. Using relative humidity as a control parameter the defrost frequency can be reduced considerably without affecting cabinet performance and product integrity. Alongside the effect of relative humidity, the paper also considers the effects of other performance parameters on the processes of frosting and defrosting such as cooling

  5. The decreasing spring frost risks during the flowering period for woody plants in temperate area of eastern China over past 50 years

    DAI Junhu; WANG Huanjiong; GE Quansheng

    2013-01-01

    The temperate monsoon area of China is an important agricultural region but late spring frosts have frequently caused significant damage to plants there.Based on phenological data derived from the Chinese Phenological Observation Network (CPON),corresponding meteorological data from 12 study sites and phenological modeling,changes in flowering times of multiple woody plants and the frequency of frost occurrence were analyzed.Through these analyses,frost risk during the flowering period at each site was estimated.Results of these estimates suggested that first flowering dates (FFD) in the study area advanced significantly from 1963 to 2009 at an average rate of-1.52 days/decade in Northeast China (P<0.01)and-2.22 days/decade (P<0.01) in North China.Over the same period,the number of frost days in spring decreased and the last frost days advanced across the study area.Considering both flowering phenology and occurrence of frost,the frost risk index,which measures the percentage of species exposed to frost during the flowering period in spring,exhibited a decreasing trend of-0.37% per decade (insignificant) in Northeast China and-1.80% per decade (P<0.01) in North China,implying that frost risk has reduced over the past half century.These conclusions provide important information to agriculture and forest managers in devising frost protection schemes in the region.

  6. Frosted branch angiitis, neuroretinitis as initial ocular manifestation in Behçet disease

    Abdullah Al-Mujaini

    2011-01-01

    Full Text Available Behçet disease is an idiopathic, multisystem disorder characterized by recurrent episodes of orogenital ulceration and vasculitis of the veins and arteries of all calibers. Ocular involvement may affect the conjunctiva, sclera, uveal tract, vitreous, blood vessels, and retina. Many theories have pointed toward an autoimmune response behind its pathogenesis, which may be triggered by exposure to an infectious agent. Frosted branch angiitis is characterized by vascular inflammation, sheathing, retinal edema, and retinal hemorrhages. The disease may be idiopathic in a majority of the cases or may be associated with ocular and systemic pathology. Association between Behηet disease, Frosted branch angiitis, and neuroretinitis is not reported in literature. This uncommon combination reflects the varied systemic and ocular manifestations in Behηet disease, especially in patients who are not diagnosed and treated in time. We hereby report a case of bilateral frosted branch angiitis and neuroretinitis in a young male from Middle-east, suffering from Behçet disease.

  7. Numerical heat transfer model for frost protection of citrus fruits by water from a spraying system

    Issa Roy J.

    2012-01-01

    Full Text Available A simplified model is developed to simulate the conditions associated with the protection of fruits from frost damage using water from a spraying system. The model simulates the movement of the solidifying water front on a single fruit, and based on that determines the spray frequency needed for a water film to continuously surround the ice-coated fruit to prevent the fruit temperature from dropping below 0ºC. Simulations are presented for the frost protection of sweet oranges (citrus sinensis. The effect of environmental conditions such as air temperature, air velocity, surface radiation and water film evaporation on the development of the ice layer encasing is considered. Simulations show the effect the encasing ice sheet thickness has on the fruit temperature if water from a spraying system is turned off permanently. Experimental tests are also conducted to determine the change in the thermal properties of citrus sinensis for operating temperatures that range from above freezing to sub-freezing. The results of the experimental tests and the numerical simulations shall lead to a better understanding of fruit protection from frost damage by the application of water from a spraying system.

  8. The Tebuconazole-based Protectant of Seeds “Bunker” Induces the Synthesis of Dehydrins During Cold Hardening and Increases the Frost Resistance of Wheat Seedlings

    A.V. Korsukova

    2015-12-01

    Full Text Available Triazole derivatives are widely used in agriculture for seed protectant of cereals against seed and soil infection. Triazole derivatives can have an effect on the biochemical and physiological functions of plants. The tebuconazole-based protectant of seeds «Bunker» (content of tebuconazole 60 grams per liter, g/L is a systemic fungicide of preventive and therapeutic action. The effect of the seed treatment by «Bunker» preparation on the shoot growth and cell viability coleoptile, synthesis of dehydrins in shoots and frost resistance etiolated winter and spring wheat seedlings has been studied. It has been shown that treatment of winter and spring wheat seed by «Bunker» preparation induces similar concentration-dependent inhibition of the coleoptiles length. At the recommended dose (0,5 liter per tonne of seeds, L/t growth inhibition was 28 - 30%, at a concentration of 1 L/t – 33 - 36%, at a concentration of 1,5 L/t – 40 - 42%, at a concentration of 3 L/t – 43 - 47%, at a concentration of 4 L/t – 48 - 51% and at 5 L/t – 53 - 56%. The treatment of wheat seed by «Bunker» preparation had no phytotoxic effect on coleoptile cells in any of the studied concentrations, on the contrary, with increasing concentration of preparation observed the increase in cell viability, as measured by recovery of 2,3,5-triphenyltetrazolium chloride. We can assume that having retardant properties, tebuconazole not only inhibits the growth of plants, but also delays their aging. The treatment of seed protectant at a concentration of 1.5 L/t induced synthesis of the dehydrins with molecular masses about 19, 21, 22, 25 and 27 kD in winter wheat shoots and 18,6, 27 and 28,5 kD in spring wheat shoots during cold hardening. Among identified dehydrins the dehydrin of 27 kD is most significantly induced both in winter and spring wheat. The treatment of seed protectant «Bunker» in the same concentration increased the frost resistance of winter and spring wheat

  9. Metals in urban playground soils

    Ljung, Karin

    2006-01-01

    Urban soils generally have elevated metal contents originating from both point and diffuse pollution sources. Urban areas designated for children, who are most susceptible to any negative health effects of soil metals, may therefore have elevated soil metal contents. Children ingest soil both directly and by putting dirty hands and objects in their mouths. The soil ingested involuntarily mainly comprise very fine particles that have a larger surface area for sorption and may therefore hold hi...

  10. Frost weathering microstructures on quartz grains as paleoenvironmental indicators in Western Iberia mountain environments (Serra da Estrela, Portugal)

    Nieuwendam, Alexandre; Woronko, Barbara; Vieira, Gonçalo

    2016-04-01

    Cailleux analysis (1942) with modifications from Mycielska-Dowgiallo and Woronko (1998) and scanning electron microscope (SEM) following Mahaney (2002) were performed on quartz grains from vertical slope deposits profiles. Other analyses include granulometric composition. The degree of weathering (ST) of single grains was determined by identifying frost-weathering microstructures. The frost action index (FAI) is the average value of the ST for a given sample. The FAI value varies between 0 and 3, and the higher the value, the more intensive the frost weathering (Woronko and Hoch, 2011). The effects of frost weathering comprise several microstructures, such as, breakage blocks and conchoidal fractures and scaling. Chemical weathering effects were also seen, like solution pits, solution crevasses and amorphous precipitation. The values of FAI index of the sediments from the slope deposits vary between 0.6 and 2.05. Samples with a FAI higher than 1.3 indicate that frost weathering occurred for a longer period and was more intense where the dominant microstructures are breakage blocks registered within microdepressions and microfissures. The samples that have a FAI below 1.3, frost weathering was less intense and for a shorter period, with less frequent freeze-thaw cycles and the dominant microstructures are small conchoidal fractures. The values of the FAI in sediments from the slope deposits reveal changes along the vertical profiles. The maximum value of frost-weathering intensity imprinted on quartz grains were observed in sediments near the base of the slope deposits, and this could be attributed to the effects of seasonal freezing and thawing, as well as to the influence of short term temperature changes. The lower frost-weathering intensity was observed in the near-surface layers probably because they were exposed to frost weathering for a shorter time. References Cailleux A. 1942. Les actiones éoliennes périglaciaires en Europe. Mémoires de la Société G

  11. The effect of watermelon frost on prostaglandin E2 (PGE2 in inflamed pulp tissue (in vitro study

    Dennis Dennis

    2009-06-01

    Full Text Available Background: Pulp inflammation can be marked by the increase of prostaglandin E2(PGE2 level compared to normal pulp. The increase of PGE2 may lead to vasodilatation, increase of vascular permeability, pain and bone resorption. Watermelon frost has been well known in Chinese society for pain relief and inflammation in oral cavity and teeth. Purpose: The aim of this study was to investigate that watermelon frost can be used to decrease the PGE2 level. Method: 27 samples of pulp tissues used in this in-vitro study, were extirpated from the patients’ teeth with symptomatic irreversible pulpitis referred to clinic of Conservative Dentistry, RSPGM Faculty of Dentistry, USU. Trial materials were applied to 27 samples i.e. watermelon frost as a trial material and commercial watermelon frost and eugenol to observe their effect on PGE2. PGE2 level of each material was detected through ELISA method by measuring and comparing the absorbance reading of the wells of the samples against standards with a micro plate reader at W1 = 650 nm and W2 = 490 nm. Result: The result showed the biggest effect was found in the third group (eugenol, mean 4.6933, followed by the first group (watermelon frost as a trial material, mean 18,1578 then the second group (commercial watermelon frost, mean 82,2689. OneWay ANOVA revealed that there were significant differences among all trial materials (p < 0.001 on PGE2 level. Conclusion: This study demonstrated that watermelon frost can be used to decrease the PGE2 level in inflamed pulp tissue and led to the acceptance of traditional medicine and natural products as an alternative form of dental care.

  12. Variation Characteristics of the Large-scale Frost in East Region of the Yellow River of Gansu in Recent 40 Years

    2011-01-01

    [Objective]The research aimed to study variation characteristics of large-scale frost in the east region of the Yellow River of Gansu in recent 40 years.[Method]Based on daily minimum temperature data at 15 meteorological stations over the east region of the Yellow River of Gansu from 1969 to 2008,according to common climatic statistical index of the frost,variation characteristics of the large-scale frost and continuous frost in the east region of the Yellow River of Gansu in recent 40 years were studied.[...

  13. 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

    Ivan Granemann de Souza Junior

    2010-03-01

    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 (χLF, 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 χLF, 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 χLF and in only 17 samples by XRD. The χLF 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 χLF values above 1.000x10-8m³ kg-1.

  14. Recent changes in frost days events characteristics in Uruguay-Southeastern South America.

    Renom, Madeleine; De Mello, Santiago

    2015-04-01

    There are few studies about extreme temperature events in Southeastern South America as is it mentioned in the SREX report (2009), although these events generate human health impacts and big economical looses. Southeastern South America is one of the major agricultural production regions worldwide. Particularly in Uruguay, agricultural production represents a high percentage of the GDP and, in the last 15 years there has been a significant increase in the area used for that economic activity. Although frost is not always is considered as an extreme event it causes, in the case of Uruguay, an impact on society, energy consumption and agricultural losses. Previous studies have shown a negative trend in the occurrence of cold nights (TN10) during winter (June-July-August) and autumn (March-April-May) in Uruguay. This work try to determine if these trends affects the occurrences and characteristics of frost days (Tmin< 0°C). Based on a high-quality daily minimum temperature for 11 meteorological stations that cover the period 1950-2009, we analyzed different features of frost days. Long term trends do not present a clear spatial behaviour suggesting that there is a not clear relationship between the percentile based index (TN10) and a fixed index (FD). At monthly scale, May and September show a negative trend, although these months present a low number of cases that difficult the statistical treatment. It is noticeable that from a decadal point of view the last decade (2000-2009) was the decade with fewer occurrences comparing with the rest, while the 90's is the decade that presents more cases. We also analyzed changes in frost period (FP) which commonly extends from May to September. In general all the stations present a decrease in the FP in accordance with the negative trend detected at monthly scale, suggesting a warming in autumn and spring time. Although we detected different behaviour in two stations, one located inner land and the other located on the

  15. Changes of Frost Damage and Treeline Advance for Swiss Stone Pine in the Calimani Mts. (Eastern Carpathians, Romania

    KERN, Zoltán

    2008-01-01

    Full Text Available Checking the tree-ring structure of 39 living and 9 crossdated dead samples of Swissstone pine (Pinus cembra L. collected from the upper timberline of the CalimaniMts. we haveidentified 59 frost rings over the past 250 years. We found concentrated occurrence of frost events inthree decades: in the 1790s, 1810s and 1910s. No frost ring was observed in two bidecadal periods:1750-1770 and 1850-1870. Out of the analysed interval 1963-2004 is the longest period without frostring occurrence. After 1920 both frequency and severity of frost events seem to decrease compared tothe prior 170 years. We determined the altitude of highest growing stone pine individuals in theBradului Ciont–Pietrosu region in June, 2006. Individuals were sorted into tree-form or bush-likemorphological groups. Mean elevation data of the groups were corrected by an estimated constant biasof GPS measurements (-30 m. Comparing the corrected values to early 20th century inventory data65 m and 95 m upward migration was determined for treeline and boundary of bush-like occurence,respectively. The parallel results suggest that the 20th century advance of the upper forest limit wasdue to the decrease of frost stress at the zone of timberline.

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

    Dong-Yeon Lee

    2012-09-01

    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.

  17. Spatiotemporal variability of the latest frosts in Korean Peninsula and causes of atmospheric circulation

    Kim, Jin-Ah; Byun, Hi-Ryong

    2016-10-01

    The spatiotemporal distributions of latest frost dates (LFDs) on the Korean Peninsula and the atmospheric circulation patterns that resulted in the latest frosts (LFs) were investigated through the use of historical records and modern weather observation data. During the modern observation period since 1904, the most recent record of LF was April 28, 2013 at Daegwallyeong. On average, the LF occurred in Korea between March 17 (at Wando) and May 10 (at Daegwallyeong). Positive correlations were found between LFD and altitude and latitude. Additionally, inter- annual variation of LFD showed a trend of progressively earlier dates at 32 of the 48 stations at which data were available. The historic data set consists of the following: 39 records of frosts during the Three-States Period (57 BC-998 AD): 34 records during the Goryeo Dynasty (998-1391), among which the latest record was in July of the lunar calendar: and 498 during the Joseon Dynasty (1392-1928) with one LF dated August 31, 1417 on the solar calendar. Regarding LFD from The Annals of the Joseon Dynasty, April has 11 records, May has 55, June has 46, July has 21, and August has 5 LFD records. Various meteorological causes of the latest LF were then established. Firstly, a cold and humid north-easterly current that originates from high latitudes of more than 50°N and passes through the East Sea is considered one of the dominant causes of LF. Secondly, strong radiative cooling under clear skies is suspected as another important cause. Thirdly, a specific pressure pattern, called the `inverted-S contour' or `North High and South Low (NHSL) pattern' was found to be a favorable condition for LF. Finally the latest LF was not found to be related to monthly or longer-term cold climate, but are instead linked to the abrupt development of a strong ridge over inland Asia and the unusual southward movement of the tall polar cyclone over the North Pacific Ocean.

  18. New BEV/E+E Elektronik Low-Frost-Point/High-Pressure Generator

    Mitter, H.

    2015-08-01

    Currently, the humidity standard at BEV/E+E is limited in the lower frost-point range to at pressures up to 1 MPa and to at ambient pressure. The system is also mainly designed for use with pure nitrogen as the carrier gas. In recent years, there has been a demand for humidity measurements in non-air gases (NAG) in contrast to "air gases" such as nitrogen, synthetic air, and -free standard air, even at pressures up to 10 MPa and in the frost-point range down to . NAGs can be gases such as , , and gas mixtures such as natural gas. To fulfill the requirements for humidity standards—especially in the high-pressure range—and to give the opportunity to determine thermodynamic properties such as enhancement factors in different carrier gases, a new "low-frost-point/high-pressure humidity generator" has been designed and verified at BEV/E+E Elektronik. The new humidity generator is designed as a single-pass generator with a maximum standard flow of and can be operated in the two-pressure mode as well as in the single-pressure mode at pressures up to 10 MPa. The design of the saturator focussed on reliability at high pressures and on achieving sufficient saturation efficiency at temperatures down to at least . First results of verification are presented in the range of saturator temperatures from to and at pressures up to 10 MPa. High-pressure data are presented for nitrogen and methane as carrier gases.

  19. CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab

    Eugene Pasyuk

    2009-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams provide unique conditions for this type of experiments. Recent addition of the Frozen Spin Target (FROST) gives a remarkable opportunity to measure double and triple polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete experiment becomes possible and will allow model independent extraction of the reaction amplitude. An overview of the experiment and its current status is presented.

  20. Assessing Wheat Frost Risk with the Support of GIS: An Approach Coupling a Growing Season Meteorological Index and a Hybrid Fuzzy Neural Network Model

    Yaojie Yue

    2016-12-01

    Full Text Available Crop frost, one kind of agro-meteorological disaster, often causes significant loss to agriculture. Thus, evaluating the risk of wheat frost aids scientific response to such disasters, which will ultimately promote food security. Therefore, this paper aims to propose an integrated risk assessment model of wheat frost, based on meteorological data and a hybrid fuzzy neural network model, taking China as an example. With the support of a geographic information system (GIS, a comprehensive method was put forward. Firstly, threshold temperatures of wheat frost at three growth stages were proposed, referring to phenology in different wheat growing areas and the meteorological standard of Degree of Crop Frost Damage (QX/T 88-2008. Secondly, a vulnerability curve illustrating the relationship between frost hazard intensity and wheat yield loss was worked out using hybrid fuzzy neural network model. Finally, the wheat frost risk was assessed in China. Results show that our proposed threshold temperatures are more suitable than using 0 °C in revealing the spatial pattern of frost occurrence, and hybrid fuzzy neural network model can further improve the accuracy of the vulnerability curve of wheat subject to frost with limited historical hazard records. Both these advantages ensure the precision of wheat frost risk assessment. In China, frost widely distributes in 85.00% of the total winter wheat planting area, but mainly to the north of 35°N; the southern boundary of wheat frost has moved northward, potentially because of the warming climate. There is a significant trend that suggests high risk areas will enlarge and gradually expand to the south, with the risk levels increasing from a return period of 2 years to 20 years. Among all wheat frost risk levels, the regions with loss rate ranges from 35.00% to 45.00% account for the largest area proportion, ranging from 58.60% to 63.27%. We argue that for wheat and other frost-affected crops, it is

  1. Development of a Frost Risk Assessment Tool in Agriculture for a Mediterranean ecosystem Utilizing MODIS satellite observations Geomatics and Surface Data

    Louka, Panagiota; Papanikolaou, Ioannis; Petropoulos, George; Migiros, George; Tsiros, Ioannis

    2014-05-01

    Frost risk in Mediterranean countries is a critical factor in agricultural planning and management. Nowadays, the rapid technological developments in Earth Observation (EO) technology have improved dramatically our ability to map the spatiotemporal distribution of frost conditions over a given area and evaluate its impacts on the environment and society. In this study, a frost risk model for agricultural crops cultivated in a Mediterranean environment has been developed, based primarily on Earth Observation (EO) data from MODIS sensor and ancillary spatial and point data. The ability of the model to predict frost conditions has been validated for selected days on which frost conditions had been observed for a region in Northwestern Greece according to ground observations obtained by the Agricultural Insurance Organization (ELGA). An extensive evaluation of the frost risk model predictions has been performed herein to evaluate objectively its ability to predict the spatio-temporal distribution of frost risk in the studied region, including comparisons against physiographical factors of the study area. The topographical characteristics that were taken under consideration were latitude, altitude, slope steepness, topographic convergence and the extend of the areas influenced by water bodies (such as lake and sea) existing in the study area. Additional data were also used concerning land use data and vegetation classification (type and density). Our results showed that the model was able to produce reasonably the spatio-temporal distribution of the frost conditions in our study area, following largely explainable patterns in respect to the study site and local weather conditions characteristics. All in all, the methodology implemented herein proved capable in obtaining rapidly and cost-effectively cartography of the frost risk in a Mediterranean environment, making it potentially a very useful tool for agricultural management and planning. The model presented here has

  2. Research on the performance of concrete lining channel frost heaving based on the finite element%基于有限元的混凝土衬砌渠道冻胀性能研究

    王圣海; 张通

    2014-01-01

    冻害分析及防治研究是混凝土衬砌渠道设计和运行管理研究的一个重要课题,尤其是在地下水位较高的冬季,受外部日照热辐射以及周期性低高温交叉变化的反复作用下,渠道混凝土衬砌面发生冻胀破坏现象尤为严重。本文在分析了影响混凝土衬砌渠道冻胀特性的土质条件、水分条件等因素后,结合有限元技术,对一大U形混凝土衬砌渠道进行建模仿真,通过数值模拟仿真结果与实际特性相比较,验证了有限元技术在渠道冻胀研究方面的可行性和准确性。%Analysis and Control of frost damage is an important topic of concrete lining channel design and management research, especially in the winter high water table ,under the repeated action by external periodic sunshine and low temperature thermal radiation cross change channels concrete frost heave damage occurred lining surface phenomenon is particularly serious.This paper analyzes the factors affecting the properties of the concrete lining channel frost heaving soil conditions,water conditions,combined with the finite element tech-nology,a large U-shaped concrete lining channels modeling and simulation,numerical simulation results and the actual characteristics compared verify the technical feasibility and accuracy of the finite element research in heaving channels.

  3. Genetic effects in callose content in root apex of inbred resistant and susceptible corn lines to acid soils Efectos genéticos de la formación de calosa en ápices radicales de líneas de maíz resistentes y susceptibles a suelos ácidos

    Arcos Alba Lucía

    2007-12-01

    Full Text Available

    The main objective of this work was to identify genetic parameters that are related to callose accumulation using tropical inbreeds corn. Fourteen inbreed lines selected for different levels of tolerance to acid soils were chosen and a diallel among them was generated. The seeds were grown under controlled environmental conditions in a growth chamber and transferred to a nutrient solution at pH 4.3. After 12 hours of 25 µM Al (AlCl3 treatment was applied, callose contents of 1 cm root apex were determined with fluorescence spectrophotometer. Significant differences were found for parents, crosses and parents vs crosses. Average callose content varied from 0.746 to 2.035 (µg PE/cm root apex. Heterosis varied from –21.2% to 276.3%. General combining ability (GCA and specific combining ability (SCA were highly significant indicating that both, additive and non–additive gene effects were important for callose inheritance. SCA and GCA sum of squares accounted for 54% and 46%, respectively of crosses of squares sum. Correlation coefficient between callose content and corn grain yield in the field was negative but not significant (r = –0.38.

    Key words: Zea mays; callose; inheritance; diallel; heterosis; acid soils.

    El objetivo de este trabajo fue estudiar la herencia de la producción de calosa utilizando líneas endogámicas de maíz. Seleccionando 14 líneas (7 tolerantes y 7 susceptibles a suelos ácidos se formó un dialelo que fue probado en campo y en invernadero. Se determinó el contenido de calosa en los 91 cruzamientos resultantes y los 14 progenitores. Para ello se colocaron las semillas en cámara de crecimiento en condiciones controladas. Después de 4–5 días las plántulas fueron transferidas a cubetas que contenían solución nutritiva con aireación constante. Luego de 48 horas se adicionaron 25 µM de aluminio (AlCl3 a cada una de las cubetas y se mantuvieron por 12 horas. Se cortaron tres ápices radicales de

  4. Numerical Simulation on Freezing Process of Saturated Granlar Soil

    2007-01-01

    The relation between ice pressure and load as a criterion of segregated ice initiation is introduced into the rigid ice model to simulate frost heave in saturated and granular soil. The calculated results show that unfrozen water content, thermal conductivity and hydraulic conductivity change greatly in frozen fringe. In numerical simulations, the influence of load, hydraulic conductivity and property of soil containing water on the process of soil freezing are analyzed, and the simulation curves such as cumulative heave,the change of depth of frozen and the distributions of water content are similar to the observations reported elsewhere.

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

    MICHAL MATYSÍK

    2011-06-01

    Full Text Available 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 ČSN EN ISO 10545-12 standard. Furthermore, accelerated degradation procedure has been applied to selected test specimens, consisting in reducing the temperature of water soaked ceramic tiles in the course of the degradation cycles down –70°C. To verify the correctness of the frequency inspection results, additional physical properties of the ceramic tiles under test have been measured, such as, the ceramic tile strength limit, modulus of elasticity and modulus of deformability, resulting from the flexural tensile strength tests, integrity defect and surface micro-geometry tracking. It has been proved that the acoustic method of frequency inspection is a sensitive indicator of the structure condition and can be applied to the ceramic cladding element frost resistance and service life prediction assessment.

  6. Frost-acclimation of photosynthesis in overwintering Mediterranean holm oak, grown in Central Europe

    Ellen Pflug

    2012-03-01

    Full Text Available As a consequence of global change, forestry in Central Europe has to expect and be prepared for an increase of hot and dry summers in the near future. In two model plantations of the Mediterranean holm oak (Quercus ilex L. in Central Europe (Rhine-Main basin we tested its potential as a future forestry tree for drought-threatened stands by studying its overwintering strategy under harsh winter conditions. During prolonged frost periods, chronic photoinhibition was developed, which lasted until the end of the frost period. Nearly all plants survived minimum temperatures of - 16 to -18°C and their photosynthetic apparatus recovered completely during late winter. A detailed study of the temperature dependence of chlorophyll (chl fluorescence parameters of the OJIP test revealed statistically significant correlations between minimum temperature and maximum quantum yield of primary photochemistry (Fv/Fm, absorption rate/reaction centre (ABS/RC, dissipation rate/reaction centre (DI0/RC and electron transport rate/reaction centre (ET0/RC as well as with the deepoxidation state (DES of the xanthophyll pigments. The DES correlated with Fv/Fm, ABS/RC, DI0/RC and ET0/RC. It is concluded, that from the point of view of the winter hardiness of the photosynthetic apparatus, Q. ilex should be further investigated as a potential future forestry tree also for very dry and warm stands in Central Europe under the scenarios of climate change.

  7. The minimum temperatures in the winter 2006/07 in the slovenian frost hollows and cold basins

    Matej Ogrin

    2007-01-01

    Full Text Available The members of Slovenian Meteorological Forum, Department of Geography at Universityof Ljubljana and Slovenian Forestry Institute started to measure temperatures in Slovenianfrost hollows and cold basins in 2004. The measurements, which improved during theperiod 2004−2006, continued also in the winter 2006−2007, all together, in more than 30frost hollows and cold basins Alpine, Dinaridic and even Submediterranean areas. Althoughthe winter 2006/2007 was very mild, minimum temperatures in frost hollow Hribarice fellbelow − 35 ˚C.

  8. There is no direct relationship between N-status and frost hardiness in needles of NH3-exposed Scots pine seedlings

    Clement, JMAM; Venema, JH; Van Hasselt, PR

    2000-01-01

    The effect of short-term atmospheric ammonia deposition on frost hardening of needles of three-month-old seedlings of Scots pine (Pinus sylvestris L.) was studied. Plants were frost hardened under short day and moderate temperature conditions in the laboratory during exposure to gaseous NH3 concentr

  9. Improving Freezing Tolerance of Cultivated Potatoes: Moving Frost Hardy Genes From Wild Potatoes and Making Real Progress Using Precise Screening Tools

    The common cultivated species Solanum tubrosum is frost sensitive and is killed at temperatures below -2.5°C. It has been estimated that by increasing frost hardiness by 1–2 C one can expect an increase in potato yield by 26 to 40% in the Altiplano (Peru and Bolivia) covering 63,000 ha. of potatoes....

  10. Toward Modelling Topsoil Magnetic Susceptibility for Demining Activities

    Hannam, J. A.; Dearing, J. A.

    2003-12-01

    The Landmine Monitor estimates that landmines cause up to 20,000 fatalities and casualties worldwide every year, in over 100 countries affected by landmine contamination. Although detection technologies have become more sophisticated, the metal detector still remains the most widely employed detection system in landmine affected regions. With increased use of minimum metal mines, the performance and sensitivity of metal detectors are increasingly challenged. In addition to mine constituents, depth of burial and orientation, soil properties significantly affect metal detection capabilities. Soils with high magnetic susceptibility, in particular those dominated by viscous components, interfere with the response signal in both frequency and time domain metal detection systems. Using Bosnia and Herzegovina (BiH) as a pilot region, we created an expert system to predict topsoil susceptibility from environmental information within a SOTER data base. Initially, the knowledge base is constructed from published relationships of environmental parameters and magnetic susceptibility and knowledge of experts in the field of soil magnetism. The knowledge base is underpinned by environmental conditions that are known to enhance or reduce magnetic susceptibility in topsoils. Where semi-quantitative data exists, transfer-functions are used to provide first approximations of susceptibility classes and offer a basis for a probability score for the susceptibility class. As a first approximation, susceptibility values are categorized into five continuous classes delimited by published magnetic susceptibility ranges in topsoils. The predicted susceptibility maps result in regional contrasts, delineated by the spatial scale of the environmental information. Further development of the model using a Baysean rule-based system with fuzzy boundaries is anticipated. Validation of the model is proposed using archived soil survey samples from BiH. In addition to providing essential data for

  11. Nitrogen split dose fertilization, plant age and frost effects on phytochemical content and sensory properties of curly kale (Brassica oleracea L. var. sabellica).

    Groenbaek, Marie; Jensen, Sidsel; Neugart, Susanne; Schreiner, Monika; Kidmose, Ulla; Kristensen, Hanne L

    2016-04-15

    We investigated how concentrations of sensory relevant compounds: glucosinolates (GLSs), flavonoid glycosides, hydroxycinnamic acid derivatives and sugars in kale responded to split dose and reduced nitrogen (N) fertilization, plant age and controlled frost exposure. In addition, frost effects on sensory properties combined with N supply were assessed. Seventeen week old kale plants showed decreased aliphatic GLSs at split dose N fertilization; whereas reduced N increased aliphatic and total GLSs. Ontogenetic effects were demonstrated for all compounds: sugars, aliphatic and total GLSs increased throughout plant development, whereas kaempferol and total flavonoid glycosides showed higher concentrations in 13 week old plants. Controlled frost exposure altered sugar composition slightly, but not GLSs or flavonoid glycosides. Reduced N supply resulted in less bitterness, astringency and pungent aroma, whereas frost exposure mainly influenced aroma and texture. N treatment explained most of the sensory variation. Producers should not rely on frost only to obtain altered sensory properties.

  12. Anti-frost Heave Study of High Speed Railway Subgrade with Different Structure%高速铁路不同路基结构防冻胀试验研究

    张振河

    2016-01-01

    In order to reduce the influence of subgrade frost heaving on high-speed railway unballasted track smoothness in seasonal frozen soil region, using different closed structure subgrade to conduct percolation model simulation under the condition of rainfall , and analysed the pressure head and water content changes of subgrade. The model simulation test results indicated that, non-closed structure discharged the groundwater of rainfall in time, the drainage plate at the top of the bottom bed layer resisted the infiltration into subgrade effectively, this structure reduced the influence of water content in bottom bed with rainfall infiltration. The deformation sensors and temperature sensors were embedded in representative test section of different closed structure to monitor the frost heaving deformation and freezing depth. The experiment results show that when the frost heave occurred at shallow depth and the under groundwater had less influence on subgrade water content, the subgrade frost heave deformation was smaller with non-closed structure.%为减小季节性冻土区路基冻胀对高速铁路无砟轨道平顺度的影响,采用对不同封闭型式的路基结构进行降雨条件下路基渗流模拟,分析路基土体内压力水头与含水量变化情况。数值模拟结果显示,路基表层无封闭型式能够在降雨时及时排出路基表面水量,基床底层顶面的排水板有效阻隔了地表水进入基床底层,降低了降雨入渗对底座板下部基床含水量的影响。在两种不同封闭型式的路基试验段,选择代表性断面埋设位移传感器与温度传感器,监测路基冻胀变形与冻结深度。现场监测结果表明,当路基主要为浅层冻胀,地下水对路基本体含水量影响较小的情况下,路基表层无封闭型式的冻胀量较小。

  13. Dynamic investigation on the coupled changing process of moisture and density fields in freezing soil

    张立新; 蒲毅彬; 廖全荣; 顾同欣

    1999-01-01

    The data reflecting the change in density are obtained, with computer tomograph scanning through the sample of freezing soil section by section at intervals without destruction. Combined with the changing characteristics of water content along the sample during test, the dynamic coupled process of moisture and density fields under the effect of temperature gradient on the freezing soil in closed system is discussed. The result reflects the internal process of frost heave improvement resulting from the transfer of mass and heat.

  14. Experimental study of no-frost refrigerator. Part 1: heat transfer through the walls; Estudo experimental de um refrigerador no-frost. Parte 1: transferencia de calor atraves das paredes

    Goncalves, Joaquim Manoel [Escola Tecnica Federal de Santa Catarina, Sao Jose, SC (Brazil)]. E-mail: joaquim@nrva.ufsc.br; Melo, Claudio; Vieira, Luis Antonio Torquato [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica

    2000-07-01

    This paper approaches the heat transfer in permanent regimen trough the walls of a no-frost refrigerator with two compartments with forced internal ventilation. The presented methodology allows the determination of thermal resistances of the walls externally. Also, the heating effect due to the compressor, the condenser and the air distribution between the compartments are investigated.

  15. Magnetic Susceptibility of Wet vs. Dry Sediment and Mass Normalized vs. Volume Normalized Magnetic Susceptibility

    Kletetschka, G.; Hruba, J.; Nabelek, L.

    2015-12-01

    The measurement of magnetic susceptibility in sediments represents a fast and non-destructive technique that can be used to deduce the concentration of magnetic minerals [1, 2]. Magnetic minerals change their magnetic properties with temperature [3]. Heating (during a fire, laboratory, with the purpose of manufacturing a product, etc.) can modify a number of sediment properties [4, 5]. Heat-induced sediment mineralogical changes may cause irreversible changes in the sediment mineral structure and composition, and they occur at a wide range of temperature [6]. We provided measurements of magnetic susceptibility on samples from the Stara Jimka (SJ) paleo lacustrine site in the Bohemian Forest using magnetic susceptibility meter MS-30. Sediment samples of approximately 0.2 cm thickness were weighed and put into plastic containers. First, measurements of magnetic susceptibility were taken on wet samples. Then the containers were put into the oven and sediment was dried at temperature of 110°C. After drying and cooling to room temperature, measurements of magnetic susceptibility were repeated. Dry samples were also weighed. Comparison of magnetic susceptibility of dry versus wet samples showed higher values of magnetic susceptibility of dry samples. This enhancement was probably caused during oven-drying, when constituents of sediment (mainly clays) underwent heat-induced changes. We also compared volume normalized values of magnetic susceptibility with mass normalized values. Mass normalized magnetic susceptibility was burdened by greater noise. References: [1] QUIJANO, L. et al. 2001. Magnetic Susceptibilty in Topsoils and Bulk Cores of Cultivated Calcisols. [2] DEARING, J. A. 1994. Environmental Magnetic Susceptibility. [3] HANESCH, M. and SCHOLGER, R. 2005. The Influence of Soil Type on the Magnetic Susceptibility Measured throughout Soil Profiles. [4] FARWIG, V. J. et al. 2004. The Effects of Heating on Mineral Magnetic Enhancement of Soils. [5] KLETETSCHKA, G

  16. Frost drought in conifers at the alpine timberline: xylem dysfunction and adaptations.

    Mayr, Stefan; Hacke, Uwe; Schmid, Peter; Schwienbacher, Franziska; Gruber, Andreas

    2006-12-01

    Drought stress can cause xylem embolism in trees when the water potential (psi) in the xylem falls below specific vulnerability thresholds. At the alpine timberline, frost drought is known to cause excessive winter embolism unless xylem vulnerability or transpiration is sufficiently reduced to avoid critical psi. We compared annual courses of psi and embolism in Picea abies, Pinus cembra, Pinus mugo, Larix decidua, and Juniperus communis growing at the timberline vs. low altitude. In addition, vulnerability properties and related anatomical parameters as well as wood density (D(t)) and wall reinforcement (wall thickness related to conduit diameter) were studied. This allowed an estimate of stress intensities as well as a detection of adaptations that reduce embolism formation. At the alpine timberline, psi was lowest during winter with corresponding embolism rates of up to 100% in three of the conifers studied. Only Pinus cembra and Larix decidua avoided winter embolism due to moderate psi. Minor embolism was observed at low altitude where the water potentials of all species remained within a narrow range throughout the year. Within species, differences in psi50 (psi at 50% loss of conductivity) at high vs. low altitude were less than 1 MPa. In Picea abies and Pinus cembra, psi50 was more negative at the timberline while, in the other conifer species, psi50 was more negative at low altitude. Juniperus communis exhibited the lowest (-6.4 +/- 0.04 MPa; mean +/- SE) and Pinus mugo the highest psi50 (-3.34 +/- 0.03 MPa). In some cases, D(t) and tracheid wall reinforcement were higher than in previously established relationships of these parameters with psi50, possibly because of mechanical demands associated with the specific growing conditions. Conifers growing at the alpine timberline were exposed to higher drought stress intensities than individuals at low altitude. Frost drought during winter caused high embolism rates which were probably amplified by freeze

  17. Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry

    Wu, Min; Fridh, Katja; Johannesson, Björn;

    2015-01-01

    Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting measureme...

  18. Bacterial blight (Pseudomonas pisi Sackett) of peas in South Africa, with special reference to frost as a predisposing factor

    Boelema, B.H.

    1972-01-01

    In the beginning of the nineteen fifties bacterial blight caused much damage to pea crops in South Africa, particularly to those grown for seed production. A study has been made of the causal organism and the conditioning factors of the disease, special attention being paid to frost as a predisposin

  19. Dimensionality and Typology of Perfectionism: The Use of the Frost Multidimensional Perfectionism Scale with Chinese Gifted Students in Hong Kong

    Chan, David W.

    2009-01-01

    This study investigated the dimensionality and typology of perfectionism based on the Frost Multidimensional Perfectionism Scale with a sample of 380 Chinese gifted students in Hong Kong. Confirmatory factor analyses supported a five-dimensional model that includes constructs of personal standards, parental expectations, parental criticism,…

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

    Hasholt, Marianne Tange

    2014-01-01

    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...

  1. Efectos genéticos de la formación de calosa en ápices radicales de líneas de maíz resistentes y susceptibles a suelos ácidos Genetic effects in callose content in root apex of inbred resistant and susceptible corn lines to acid soils

    Alba Lucía Arcos

    2007-01-01

    Full Text Available El objetivo de este trabajo fue estudiar la herencia de la producción de calosa utilizando líneas endogámicas de maíz. Seleccionando 14 líneas (7 tolerantes y 7 susceptibles a suelos ácidos se formó un dialelo que fue probado en campo y en invernadero. Se determinó el contenido de calosa en los 91 cruzamientos resultantes y los 14 progenitores. Para ello se colocaron las semillas en cámara de crecimiento en condiciones controladas. Después de 4-5 días las plántulas fueron transferidas a cubetas que contenían solución nutritiva con aireación constante. Luego de 48 horas se adicionaron 25 µM de aluminio (AlCl3 a cada una de las cubetas y se mantuvieron por 12 horas. Se cortaron tres ápices radicales de cada genotipo y se mantuvieron en etanol 96%. Para medir el contenido de calosa se utilizó Methyl blue como colorante, este forma un complejo con la calosa llamado Siruflúor-calosa, que es medido con el espectrofotómetro de fluorescencia. Se encontraron diferencias significativas para los progenitores, los cruzamientos y los progenitores Vs cruzamientos. El contenido de calosa de los progenitores varió de 0.746 a 2.035 µg PE/cm ápice de raíz. La heterosis varió desde -21.2% a 276.3%. La Habilidad Combinatoria General (HCG y la Habilidad Combinatoria Específica (HCE fueron altamente significativas, lo que indica que tanto los efectos genéticos aditivos y no aditivos fueron importantes en la herencia de calosa. El 46% de SC entre cruzamientos correspondió a la HCG y el 54% a la HCE. El coeficiente de correlación entre el contenido de calosa y la producción de grano del maíz en el campo fue negativo aunque no significativo (r = -0.38.The main objective of this work was to identify genetic parameters that are related to callose accumulation using tropical inbreeds corn. Fourteen inbreed lines selected for different levels of tolerance to acid soils were chosen and a diallel among them was generated. The seeds were grown

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

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

    1999-09-01

    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.

  3. Dynamic Simulation and Performance Investigation of No-frost Refrigerator: Part Ⅰ Mathematical Model

    SU Xiu-ping; CHEN Jiang-ping; CHEN Zhi-jiu; ZHOU Xiao-tian

    2009-01-01

    A dynamic approach for the modeling, simulation and analysis of no-frost Refrigerator (RF) is dis-cussed. In Part Ⅰ, the complex interactions among the components in the cooling system are analyzed in detail, based on which the modeling simplifications are proposed. Then, the mathematical models for the evaporator, cabinet and duct-fan are presented. The whole system is divided into two subsystems-refrigerant cycling system and air cycling system. In order to simplify the model, two closed-loop systems are broken into the compressor component and the evaporator component, respectively. A general distributed parameter model is employed for evaporator with homogeneous flow to simplify the two-phase evaporating flow region. The z-transfer function model is used to describe the cabinet load. Computational fluid dynamics (CFD) method is employed to obtain the pressure drop and flow rate curve of the duct-fan model.

  4. On Bird Image in Frost's Poetry%论弗罗斯特诗歌中的鸟意象

    刘保安

    2014-01-01

    弗罗斯特的诗歌中有很多鸟意象。弗罗斯特以鸟意象展现了人与鸟之间的关系以及鸟与自然之间的关系。弗罗斯特诗歌中的鸟意象具有一定的象征意义。弗罗斯特以孤独的鸟儿象征现代人的孤独,以鸟象征自己的诗歌创作,以各种各样的鸟儿象征20世纪初美国诗坛上众多的诗派,以凄清的鸟鸣象征现代人的忧伤心境,以鸟的鸣叫象征恐惧。弗罗斯特以鸟意象再现了他对现代人的关怀。弗罗斯特在其诗歌中频繁地展现鸟意象旨在告诫读者热爱自然,维护生态平衡,保护人类的家园。%There are many bird images in Frost's poems. By bird image Frost reflects the relation between man and bird and that between bird and nature. Bird image in Frost's poems has symbolic meanings. Lone-ly bird symbolizes modern man's loneliness, bird signifies his poetry composition, while various birds denote the diverse poetic schools in the early 20 th American poetry scene, the sad song of the bird stands for modern man's sad minds, and the crying of the bird for terror. Frost shows great concern for modern people by using bird image. That Frost repeatedly reflects bird image in his poems is to warn the readers to love nature, keep ecological balance and protect human beings' homestead.

  5. Inter population variability of frost-resistance in provenances of scot pines (Pinusylvestris L.R. hamata Steven in Turkey

    Özel Halil Barış

    2016-01-01

    Full Text Available Frost-resistance variability of Scotch pine (Pinus sylvestris L. var. hamata Steven seedlings grown in nurseries conditions, originated from 10 provenances, have been analyzed. The provenances from Black Sea region, Central Anatolian region and Eastern Anatolian region in Turkey have been used in selection of seed zones. The results of frost-resistance tests indicated a strong relationship of implemented freezing degrees with injury degrees of Scotch pine needles and photosynthetic productivities. On the other hand, another significant relationship has been determined between chlorophyll fluorescence and ion leakage methods (r=-0.801. This result shows that those two methods can be safely used in determining the damages due to low temperatures. In frost resistance tests, Scotch pine seedlings from different provenances have been frozen at -10, -20, -30 and -40°C. According to the Duncan test results, it has been determined that damage increased as temperature decreased. The damage level at -10°C implementation is 3.5% which can be tolerated by plants. But when the temperature has been decreased to -20°C, the level of damage has increased to 51.25%. As a result of photosynthetic analyses in this phase, it has been determined that there is a statistically significant relationship between provenances and temperature levels. Under the light of those findings, they have determined that the photosynthetic productivity has significantly decreased at temperatures between -20°C and -40°C. This situation conforms to injury index values determined in this study. As a result of injury index and photosynthetic productivity tests used for determining the damage after frost-resistance tests, it has been determined that the provenances of Amasya-Kunduz, Bolu-Aladağ, Düzce-Yığılca, Samsun-Vezirköprü and Eskişehir-Çatacık are more sensitive to frost than other provenances.

  6. The role of the observed tropical convection in the generation of frost events in the southern cone of South America

    Mueller, G.V. [Centro de Investigacion Cientifica y de Transferencia Tecnologica a la Produccion (CICYTTP/CONICET), Diamante (Argentina); Ambrizzi, T. [Universidade de Sao Paulo (Brazil). Dept. de Ciencias Atmosfericas; Ferraz, S.E. [Universidade Federal de Santa Maria/CRSPE-INPE (Brazil). Dept. de Fisica

    2008-07-01

    Based on previous results obtained from observations and linear wave theory analysis, the hypothesis that large-scale patterns can generate extreme cold events in southeast South America through the propagation of remotely excited Rossby waves was already suggested. This work will confirm these findings and extend their analysis through a series of numerical experiments using a primitive equation model where waves are excited by a thermal forcing situated in positions chosen according to observed convection anomalies over the equatorial region. The basic state used for these experiments is a composite of austral winters with maximum and minimum frequency of occurrence of generalized frosts that can affect a large area known as the Wet Pampas located in the central and eastern part of Argentina. The results suggest that stationary Rossby waves may be one important mechanism linking anomalous tropical convection with the extreme cold events in the Wet Pampas. The combination of tropical convection and a specific basic state can generate the right environment to guide the Rossby waves trigged by the tropical forcing towards South America. Depending on the phase of the waves entering the South American continent, they can favour the advection of anomalous wind at low levels from the south carrying cold and dry air over the whole southern extreme of the continent, producing a generalized frost in the Wet Pampa region. On the other hand, when a basic state based on the composites of minimum frosts is used, an anomalous anticyclone over the southern part of the continent generates a circulation with a south-southeast wind which brings maritime air and therefore humidity over the Wet Pampas region, creating negative temperature anomalies only over the northeastern part of the region. Under these conditions even if frosts occur they would not be generalized, as observed for the other basic state with maximum frequency of occurrence of generalized frosts. (orig.)

  7. Characterization of sound emitted by wind machines used for frost control

    Gambino, V.; Gambino, T. [Aercoustics Engineering Ltd., Toronto, ON (Canada); Fraser, H.W. [Ontario Ministry of Agriculture, Food and Rural Affairs, Vineland, ON (Canada)

    2007-07-01

    Wind machines are used in Niagara-on-the-Lake to protect cold-sensitive crops against cold injury during winter's extreme cold temperatures,spring's late frosts and autumn's early frosts. The number of wind machines in Ontario has about doubled annually from only a few in the late 1990's, to more than 425 in 2006. They are not used for generating power. Noise complaints have multiplied as the number of wind machines has increased. The objective of this study was to characterize the sound produced by wind machines; learn why residents are annoyed by wind machine noise; and suggest ways to possibly reduce sound emissions. One part of the study explored acoustic emission characteristics, the sonic differences of units made by different manufacturers, sound propagation properties under typical use atmospheric conditions and low frequency noise impact potential. Tests were conducted with a calibrated Larson Davis 2900B portable spectrum analyzer. Sound was measured with a microphone whose frequency response covered the range 4 Hz to 20 kHz. The study examined and found several unique acoustic properties that are characteristic of wind machines. It was determined that noise from wind machines is due to both aerodynamic and mechanical effects, but aerodynamic sounds were found to be the most significant. It was concluded that full range or broadband sounds manifest themselves as noise components that extend throughout the audible frequency range from the bladepass frequency to upwards of 1000 Hz. The sound spectrum of a wind machine is full natural tones and impulses that give it a readily identifiable acoustic character. Atmospheric conditions including temperature, lapse rate, relative humidity, mild winds, gradients and atmospheric turbulence all play a significant role in the long range outdoor propagation of sound from wind machines. 6 refs., 6 figs.

  8. Effects of Spring Late Frost on Black Seed (Nigella sativa L. under Controlled Conditions

    T Khorsandi

    2015-04-01

    Full Text Available In many years plant growth strongly affected by late spring frost. In order to evaluate the effects of late frost on Black Seed plants, a factorial experiment based on completely randomized design with three replications was carried out in college of agriculture, Ferdowsi University of Mashhad and five Black Seed ecotypes (Birjsnd, Sabzewar, Ferdows, Gonabad and Neyshabour after two months growth and hardening in natural environment, were exposed to seven temperatures (0, -1.5, -3, -4.5, -6, -7.5 and -9°C in termogradient freezer. For determining cold stress damages, Lethal Temperature (LT for 50% of plants according to the Electrolyte Leakage percentage (LT50el, LT for 50% of plants according to the Survival percentage (LT50su, LT for 50% of plants according to the plant necrose in Test Tube (LT50tt and Reduced Dry Matter Temperature 50 (RDMT50 were measured. Ability of plants for recovery was recorded based on leaf number and leaf area, plant dry weight and cold damage percentage of leaves. According to the LT50tt, LT50su and RDMT50 Black Seed plants can tolerated cold stress in range between -5.7 to -9.0 °C and Sabzewar and Ferdows ecotypes had the most and the least cold tolerance, respectively. At the point of ability of plants for recovery, Ferdows ecotype had the least and Sabzewar and Neyshabour ecotypes had the best plant recovery. Moreover there were high correlations between LT50tt and LT50 based on electrolyte leakage, survival and RDMT50. Electrolyte leakage and visual scoring of cold damage in test tube are rapid methods, so for assessing cold tolerance in plants LT50el and LT50tt indeces may be useful.

  9. Physical Properties of CO2 Frost Formed by Radiative Cooling in a Mars Simulation Chamber

    Wood, Stephen; Bruckner, A.; Hansen, G.; Cornwall, C.; Kimber, N.; Alvarez, F.

    2013-10-01

    We have performed realistic laboratory simulations of the thermal and radiative environment at the surface of Mars to produce the first samples of carbon dioxide ice formed as it does on Mars, by radiative cooling from a near-pure CO2 gas. It is important to determine the physical characteristics of Mars' seasonal CO2 polar ice caps because these determine their radiative properties which, in turn, control the polar energy balance and the seasonal variation in global surface pressure. It is not known whether they form as fluffy fine-grained deposits, dense solid ice, or something in between. Previous simulations have used conductive cooling, condensing CO2 onto a substrate cooled by liquid nitrogen (Kieffer 1968, Ditteon and Kieffer 1979). This technique favors the growth of grains having the best thermal contact with the surface, resulting in large grain sizes and a coarse texture. On Mars, however, the latent heat released by condensation must be lost radiatively to space. For this experiment, we have constructed a Mars simulation chamber containing low thermal conductivity analog regolith and low pressure CO2 gas. To grow radiation frost in the laboratory requires simultaneous containment of the atmosphere/vapor while allowing infrared radiation to escape (to balance the latent heat of condensation). Planets accomplish this using gravity to hold down the atmosphere. The key to our simulation is the use of a thin polypropylene film that is largely transparent in the thermal infrared yet strong enough to maintain the required pressure differential between our Mars-like "atmosphere" and the vacuum-enclosed space simulator (a liquid-nitrogen cooled plate). We use internal and external light sources to briefly illuminate the frost and obtain high resolution images of its physical morphology and texture using an in situ fiberscope with an articulated tip. Initial results will be presented.

  10. Analysis on the Climate Variation Characteristics of Frost in Shandong Province%山东省霜冻的气候变化特征分析

    王业宏; 高慧君; 张璇

    2011-01-01

    [ Objective ] The research aimed to study the climate variation characteristics of frost in Shandong Province. [ Method ] The daily minimum surface temperature ≤0 ℃ in autumn or spring was as the frost index. Based on the daily surface minimum temperature data in 67 meteorological observatories of Shandong Province during 1961 -2008, the variation characteristics of first, last frost dates and the frost-free period in Shandong Province were analyzed by using the climate diagnosis analysis method. [ Result] The climate characteristics of first, last frost dates and the frost-free period had the significant geographical difference in Shandong Province in recent 48 years. The extreme differences of first, last frost dates and the frost-free period were all above the three times of their standard deviations, which illustrated that the dispersion degrees of first, last dates and the frost-free period were all very big. The average first frost date postponed with 1.99 d/10a velocity in Shandong Province in recent 48 years, and the last frost date advanced with 1.46 d/10a velocity. The postponing range of first frost date was bigger than the advancing range of last frost date, and the frost-free period prolonged with 3.42 d/10a velocity. Seen from the interdecadal variations, the first frost date started to obviously postpone, and the last frost date obviously advanced since the 1990s. The frost-free period started to obviously prolong since the 1990s. [ Conclusion] The research provided the certain reference for the predication, prevention of frost disaster and the structure adjustment of crops.%[目的]研究山东省霜冻的气候变化特征.[方法]以秋季或春季日最低地面温度≤0℃作为霜冻指标,利用1961~2008年山东省67个气象监测站的逐日地面最低温度资料,采用气候诊断分析方法,对山东省初、终霜日期和无霜期的变化特征进行了分析.[结果]近48年来,山东省的初、终霜日和无霜期的气

  11. MR susceptibility imaging

    Duyn, Jeff

    2013-04-01

    This work reviews recent developments in the use of magnetic susceptibility contrast for human MRI, with a focus on the study of brain anatomy. The increase in susceptibility contrast with modern high field scanners has led to novel applications and insights into the sources and mechanism contributing to this contrast in brain tissues. Dedicated experiments have demonstrated that in most of healthy brain, iron and myelin dominate tissue susceptibility variations, although their relative contribution varies substantially. Local variations in these compounds can affect both amplitude and frequency of the MRI signal. In white matter, the myelin sheath introduces an anisotropic susceptibility that has distinct effects on the water compartments inside the axons, between the myelin sheath, and the axonal space, and renders their signals dependent on the angle between the axon and the magnetic field. This offers opportunities to derive tissue properties specific to these cellular compartments.

  12. Frost damage of bricks composing a railway tunnel monument in Central Japan: field monitoring and laboratory simulation

    C. Thomachot

    2005-01-01

    Full Text Available Bricks of tunnels and bridges of Usui Pass railway (Japan exposed to north are subject to frost damage. Average depth of erosion due to detachment of angular blocks is around 1-1.5 cm. In order to assess this weathering and to understand its mechanism, an experimental study was carried out in the field and laboratory. Field monitoring showed the combination of seasonal and diurnal freezing with a maximum of heave when the freezing front reached 5 cm depth. Bricks taken from the site were submitted to unidirectional freezing at capillary and vacuum saturation in the laboratory. Results showed that frost damage of bricks was favoured by high saturation level and repetition of freeze-thaw cycles.

  13. Seasonally active frost-dust avalanches on a north polar scarp of Mars captured by HiRISE

    Russell, P.; Thomas, N.; Byrne, S.; Herkenhoff, K.; Fishbaugh, K.; Bridges, N.; Okubo, C.; Milazzo, M.; Daubar, I.; Hansen, C.; McEwen, A.

    2008-01-01

    North-polar temporal monitoring by the High Resolution Imaging Science Experiment (HiRISE) orbiting Mars has discovered new, dramatic examples that Mars1 CO2-dominated seasonal volatile cycle is not limited to quiet deposition and sublimation of frost. In early northern martian spring, 2008, HiRISE captured several cases of CO2 frost and dust cascading down a steep, polar scarp in discrete clouds. Analysis of morphology and process reveals these events to be similar to terrestrial powder avalanches, sluffs, and falls of loose, dry snow. Potential material sources and initiating mechanisms are discussed in the context of the Martian polar spring environment and of additional, active, aeolian processes observed on the plateau above the scarp. The scarp events are identified as a trigger for mass wasting of bright, fractured layers within the basal unit, and may indirectly influence the retreat rate of steep polar scarps in competing ways. Copyright 2008 by the American Geophysical Union.

  14. Local adaptations to frost in marginal and central populations of the dominant forest tree Fagus sylvatica L. as affected by temperature and extreme drought in common garden experiments.

    Kreyling, Juergen; Buhk, Constanze; Backhaus, Sabrina; Hallinger, Martin; Huber, Gerhard; Huber, Lukas; Jentsch, Anke; Konnert, Monika; Thiel, Daniel; Wilmking, Martin; Beierkuhnlein, Carl

    2014-03-01

    Local adaptations to environmental conditions are of high ecological importance as they determine distribution ranges and likely affect species responses to climate change. Increased environmental stress (warming, extreme drought) due to climate change in combination with decreased genetic mixing due to isolation may lead to stronger local adaptations of geographically marginal than central populations. We experimentally observed local adaptations of three marginal and four central populations of Fagus sylvaticaL., the dominant native forest tree, to frost over winter and in spring (late frost). We determined frost hardiness of buds and roots by the relative electrolyte leakage in two common garden experiments. The experiment at the cold site included a continuous warming treatment; the experiment at the warm site included a preceding summer drought manipulation. In both experiments, we found evidence for local adaptation to frost, with stronger signs of local adaptation in marginal populations. Winter frost killed many of the potted individuals at the cold site, with higher survival in the warming treatment and in those populations originating from colder environments. However, we found no difference in winter frost tolerance of buds among populations, implying that bud survival was not the main cue for mortality. Bud late frost tolerance in April differed between populations at the warm site, mainly because of phenological differences in bud break. Increased spring frost tolerance of plants which had experienced drought stress in the preceding summer could also be explained by shifts in phenology. Stronger local adaptations to climate in geographically marginal than central populations imply the potential for adaptation to climate at range edges. In times of climate change, however, it needs to be tested whether locally adapted populations at range margins can successfully adapt further to changing conditions.

  15. Warming in the Yukon River Basin is Likely to Release Substantial Amounts of Soil Organic Carbon

    Juday, G. P.; Huntington, T. G.

    2005-12-01

    In recent decades the Yukon River Basin (YRB) in northwestern Canada and central Alaska has experienced a substantial warming trend resulting in a variety of geophysical and biological responses. Climatologic measurements consistent with rapid warming in the YRB during the last several decades of the 20th century include surface air temperature (especially daily minima), number of frost-free days, and the number of very warm days. During the 20th century daily maxima in the warm season in the YRB have increased only weakly, and modest autumn cooling occurred. Indirect indicators of warming include shrinkage in lake area, decreases in glacier mass, increased fire frequency and annual area burned, and changes in permafrost thickness and permafrost temperature. Changes in tree growth rates and susceptibility to pests have been related to warming and drying in interior Alaska. Oral histories of Alaska Natives have also revealed many other warming related changes in the YRB. If ongoing warming trends continue there is a concern that large stores of soil organic carbon (SOC) will be at risk for release to the atmosphere through heterotrophic decomposition. Warming tends to accelerate microbial decomposition at a faster rate than net primary productivity. One of the most important effects of warming in the YRB is likely to be its influence on the hydrologic and cryospheric regimes. Warming may be accompanied by soil drying and lowering of the water table in wetlands and lakes exposing more SOC to aerobic decomposition. A substantial portion of the YRB is underlain by permafrost that thaws to a variable depth (active layer) each summer. Increasing the thickness of the active layer exposes more SOC to microbial decomposition. Increasing the burned area results in direct SOC losses by oxidation during the fire and decreases albedo that warms surface soils and increases the thickness of the active layer. Warming and increasing length of the growing season increases seasonal

  16. Tree-Temperature Monitoring for Frost Protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation

    Ali Asghar Ghaemi; Mohammad Rafie Rafiee; Ali Reza Sepaskhah

    2009-01-01

    Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran (a 0.17 ha peach orchard and a 0.24 ha orange orchard) to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO. In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 (control block -4.12℃, and sprinkled block+0.5℃) during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins (about 3.6% of the total area) were at the risk of low temperature due to the wind drift effects.

  17. Species of Ice Nucleation Active Bacteria on the Apricot and the Relationship Between Their Activity and Flower Frost

    SUN Fu-Zai; ZHAO Ting-chang; YANG Jian-min; CAO Xiao-yu; TANG Chao-rong; MENG Qing-rui

    2001-01-01

    During 1996- 1997, sixty samples were collected from apricot in Hebei Province, from which nineteen ice nucleation active bacterial strains were isolated. Nine stains were identified as Pseudomonas syringae pv. syringae by bacteriological determination, while the others were Erwinia uredovora. Assay of ice nucleation activity (INA) showed the activity of the Pseudomonas strains was higher than that of the Erwinia.According to the number of bacterial cells required to produce one ice nucleus active at - 3℃, four stains was classified as strong ones, three as medium-strong, the remainder as weak. In general, the INA of these strains were regarded as medium-strong. Under stress of Iow temperatures, treatment of INA bacteria can greatly raised relative electric conductivity of petals and permeability of cell membrane. The treated petals showed symptoms of serious frost at - 3 - - 4℃ and had supercooling points of 2 - 3℃ higher than controls. Our results demon strated that INA bacteria are one major factor to incite frost damage to apricot flowers. We may reduce frost injury to apricot during flowering phage through control of INA bacteria.

  18. Clay mineralogy and magnetic susceptibility of Oxisols in geomorphic surfaces

    Livia Arantes Camargo

    2014-06-01

    Full Text Available 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, magnetic 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.

  19. Psychometric proprieties of the portuguese version of the frost multidimensional perfectionism scale

    Marco Estêvão Coreia

    2017-01-01

    Full Text Available Perfectionism is defined as the desire to achieve the highest standards of performance, in combination with unduly critical evaluations of one’s performance. This study was designed to analyse the psychometric proprieties of the Portuguese version of the Frost Multidimensional Perfectionism Scale through confirmatory factor analysis in two different samples (calibration with 350 adolescent athletes and validation with 206 adolescent athletes. The confirmatory factor analysis suggested that after dropping items with low factor loadings, the six-factor model showed good fit (χ 2 = 292.83, B-S p < 0.001; χ 2/d f = 1.693, PCFI = 0.79, PGFI = 0.70, CFI = 0.96, GFI = 0.93, RMSEA = 0.045. All constructs presented good internal consistency, convergent and discriminant validity. A multi-group analysis exposed the cross validity of the model. The correlations between perfectionism, fear of failure and sport anxiety measures revealed evidence of its concurrent validity, providing evidence for the proposed model. Overall, the results of the present study provided evidence for these instruments’ validity and reliability, however further investigations are required.

  20. Electro-thermal protection system design against atmospheric frost on turbine blades

    Noui, M.A.; Perron, J.; Fortin, G. [Quebec Univ., Chicoutimi, PQ (Canada). Anti-Icing Materials International Laboratory

    2010-07-01

    This presentation discussed a research program developed to adapt de-icing thermal heating systems for use in wind turbines. The presence of ice on turbine blades can significantly deteriorate rotor performance. Accumulations of ice can increase the radial load on the turbine blades. The uneven formations of ice can lead to vibrations and the expulsion of pieces of ice into surrounding areas. Ice can also reduce the accuracy of various wind measuring devices. A recent study in Finland showed that turbine heating systems consume 3.6 per cent of annual wind production energy. De-icing systems include protective covers; air inlets; sealing systems; inflation tubes; elastomeric ply; and bond ply. The systems also include blade trailing and loading edges, and blade roots. The energy dissipated by the system's heating element is lost by conduction to the interior of the profile. The research program is now developing a system to improve electrothermal protection against frost that is suitable for turbine blades, as well as a thermal model for simulating its operation in a wind turbine. tabs., figs.

  1. Genetic susceptibility of periodontitis

    Laine, M.L.; Crielaard, W.; Loos, B.G.

    2012-01-01

    In this systematic review, we explore and summarize the peer-reviewed literature on putative genetic risk factors for susceptibility to aggressive and chronic periodontitis. A comprehensive literature search on the PubMed database was performed using the keywords ‘periodontitis’ or ‘periodontal dise

  2. A study of surfactant interaction in cement-based systems and the role of the surfactant in frost protection

    Tunstall, Lori Elizabeth

    Air voids are deliberately introduced into concrete to provide resistance against frost damage. However, our ability to control air distribution in both traditional and nontraditional concrete is hindered by the limited amount of research available on air-entraining agent (AEA) interaction with both the solid and solution components of these systems. This thesis seeks to contribute to the information gap in several ways. Using tensiometry, we are able to quantify the adsorption capacity of cement, fly ash, and fly ash carbon for four commercial AEAs. These results indicate that fly ash interference with air entrainment is due to adsorption onto the glassy particles tucked inside carbon, rather than adsorption onto the carbon itself. Again using tensiometry, we show that two of the AEA show a stronger tendency to micellize and to interact with calcium ions than the others, which seems to be linked to the freezing behavior in mortars, since mortars made with these AEA require smaller dosages to achieve similar levels of protection. We evaluate the frost resistance of cement and cement/fly ash mortars by measuring the strain in the body as it is cooled and reheated. All of the mortars show some expansion at temperatures ≥ -42 °C. Many of the cement mortars are able to maintain net compression during this expansion, but none of the fly ash mortars maintain net compression once expansion begins. Frost resistance improves with an increase in AEA dosage, but no correlation is seen between frost resistance and the air void system. Thus, another factor must contribute to frost resistance, which we propose is the microstructure of the shell around the air void. The strain behavior is attributed to ice growth surrounding the void, which can plug the pores in the shell and reduce or eliminate the negative pore pressure induced by the ice inside the air void; the expansion would then result from the unopposed crystallization pressure, but this must be verified by future work

  3. Freezing pattern and frost killing temperature of apple (Malus domestica) wood under controlled conditions and in nature.

    Pramsohler, Manuel; Hacker, Jürgen; Neuner, Gilbert

    2012-07-01

    The freezing pattern and frost killing temperatures of apple (Malus domestica Borkh.) xylem were determined by differential thermal analysis and infrared differential thermal analysis (IDTA). Results from detached or attached twigs in controlled freezing experiments and during natural field freezing of trees were compared. Non-lethal freezing of apoplastic water in apple xylem as monitored during natural winter frosts in the field occurred at -1.9 ± 0.4 °C and did not change seasonally. The pattern of whole tree freezing was variable and specific to the environmental conditions. On detached twigs high-temperature freezing exotherms (HTEs) occurred 2.8 K below the temperature observed under natural frosts in the field with a seasonal mean of -4.7 ± 0.5 °C. Microporous apple xylem showed freezing without a specific pattern within a few seconds in IDTA images during HTEs, which is in contrast to macroporous xylem where a 2D freezing pattern mirrors anatomical structures. The pith tissue always remained unfrozen. Increasing twig length increased ice nucleation temperature; for increased twig diameter the effect was not significant. In attached twigs frozen in field portable freezing chambers, HTEs were recorded at a similar mean temperature (-4.6 ± 1.0 °C) to those for detached twigs. Upon lethal intracellular freezing of apple xylem parenchyma cells (XPCs) low-temperature freezing exotherms (LTEs) can be recorded. Low-temperature freezing exotherms determined on detached twigs varied significantly between a winter minimum of -36.9 °C and a summer maximum -12.7 °C. Within the temperature range wherein LTEs were recorded by IDTA in summer (-12.7 ± 0.5 to -20.3 ± 1.1 °C) various tiny clearly separated discontinuous freezing events could be detected similar to that in other species with contrasting XPC anatomy. These freezing events appeared to be initially located in the primary and only later in the secondary xylem. During the LTE no

  4. Genetic Susceptibility to Atherosclerosis

    Sanja Kovacic

    2012-01-01

    Full Text Available 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 number is rapidly increasing. This paper discusses main genetic investigations fields associated with human atherosclerotic vascular diseases. The paper concludes with a discussion of the directions and implications of future genetic research in arteriosclerosis with an emphasis on prospective prediction from an early age of individuals who are predisposed to develop premature atherosclerosis as well as to facilitate the discovery of novel drug targets.

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

    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

    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.)

  6. Relationship between parameters of electrical impedance spectroscopy and frost hardiness in stems and needles of Pinus bun(g)eana

    Yaqing LI; Gang ZHANG; Shupeng QUE; Liang ZHU; Bao DI; Xiumei JIN

    2009-01-01

    We studied the frost hardiness (FH) in stems and needles of different Pinus bungeana provenances during frost hardening by means of electrical impedance spectroscopy (EIS) and conventional electrolytic leakage (EL) and compared the regression equations of the two methods in order to optimize the EIS method for studying FH on plants. During frost hardening, EIS and EL were applied to one-year old stems and needles of P. bungeana in an 8-year provenance field trial at the Thirteen Tombs Nursery in Beijing within the provenances of Mangshan of Beijing, Liangdang of Gansu and Xiaoyi of Shanxi provinces, China. A double-DCE model and Model-A were used, respectively, for the EIS analysis of stems and needles that were not exposed to a controlled freezing treatment. After controlled freezing tests, the FH of stems and needles were assessed by EIS and EL. Without controlled freezing tests, the relaxation time (τ1) of stems and the specific intracellular resistance (ri) of stems and needles displayed a statistically significant correlation with FH (R2 =0.79-0.86); after controlled freezing tests, specific extracellular resistance (re) of the stems and needles, the cell membrane time constant (τm) of needles displayed an even higher correlation with FH (R2 = 0.92-0.94). There were significant relationship between EIS and EL in assessing the FH of stems and needles of P, bungeana, but EIS underestimated FH more than EL did. EIS is one of the more promising methods for assessing FH, especially without employing a controlled freezing test.

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

    Kyvsgaard, Niels Chr.; Johansen, Maria Vang; Carabin, Hélène

    2007-01-01

    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...... 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...

  8. Compressive strength and frost heave resistance of different types of semi-rigid base materials after freeze-thaw cycles

    ZhenYa Liu; JingYu Liu; QingZhi Wang; JianKun Liu

    2015-01-01

    Freeze-thaw damage is the most common disease of semi-rigid bases in cold regions, which may greatly affect the dura-bility of roadways. In this study, the compressive strength and frost resistance of four different types of semi-rigid bases (lime-fly ash-stabilized sand, cement-stabilized sand, lime-fly ash-stabilized gravel, and cement-stabilized gravel) are assessed by varying the materials content. Based on freeze-thaw and compressive strength tests, this paper presents the performance of the different materials, each having different physical properties, and the optimal amounts of materials contents are proposed.

  9. 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

    A. J. Hernández

    2010-01-01

    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

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

    Quénol, H.; Planchon, O.; Wahl, L.

    2009-04-01

    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

  11. Climate-change effects on soils: Accelerated weathering, soil carbon and elemental cycling

    Qafoku, Nikolla

    2015-04-01

    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, identifies key research needs, and highlights opportunities offered by the climate-change effects on soils.

  12. Frost hardiness in walnut trees (Juglans regia L.): how to link physiology and modelling?

    Charrier, Guillaume; Poirier, Magalie; Bonhomme, Marc; Lacointe, André; Améglio, Thierry

    2013-11-01

    In the literature, frost hardiness (FH) studies in trees have often been restricted to one organ (buds, leaves, needles or twigs). To extend our knowledge and gain a unified view, FH differences between organs and tissues or throughout the life of the tree have to be characterized in relation to physiological changes. In this study, different organs and tissues of young potted and mature orchard walnut trees (Juglans regia L.) were compared for seasonal changes in FH during different years. FH was assessed using the electrolyte leakage method. Physiological parameters were concomitantly monitored focusing on two significant traits: water content (WC) and carbohydrate content (glucose + fructose + sucrose, GFS). No seasonal variation in FH was observed in the root system, but acclimation and deacclimation were observed aboveground. Among organs and tissues, cold sensitivity levels were different in deep winter, with buds most sensitive and bark most resistant, but acclimation/deacclimation dynamics followed similar patterns. Physiological variation was also similar among organs: FH increased when WC decreased and/or soluble carbohydrates increased. Based on these results, relations between soluble carbohydrate content, WC and FH were calculated independently or in interaction. The key results were that: (i) the relationship between FH and physiological parameters (GFS and WC), which had previously been shown for branches only, could be generalized to all aboveground organs; (ii) lower WC increased the cryoprotective effect of GFS, showing a synergic effect of the two factors; (iii) the best fit was a non-linear function of WC and GFS, yielding a predictive model with an root mean square error of 5.07 °C on an independent dataset and 2.59 °C for the most sensitive stages; and (iv) the same parameters used for all organs yielded a unified model of FH depending on physiology, although the variability of GFS or WC was wide. The model should be of value for predicting

  13. Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

    Zhang Gang; Jaana Luoranen; Heikki Smolander

    2007-01-01

    In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus,frost hardening is usually delayed. To solve this problem, We used a three-week period of short-day (SD) treatment between late July and mid-August. During autumn after frost exposure,frost hardiness (FH) Was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore,the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

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

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

    2014-08-01

    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.

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

    I.V. Lyubushkina

    2013-11-01

    Full Text Available Influences of low temperatures (4 and 8 ° С 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 °С, 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 α-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.

  16. Highway Roadway Stability Influenced by Warm Permafrost and Seasonal Frost Action:A Case Study from Glennallen,Alaska,USA

    Max; C.Brewer

    2008-01-01

    Ground temperatures from four of the seven extensively studied highway cross-sections near Gulkana/Glennallen,Alaska during 1954~1962,were chosen to better understand the impacts of highway construction on warm permafrost.Both the thawing of permafrost and seasonal frost action impacted on road surface stability for about 6 years until the maximum summer thaw reached about 3 m in depth.Seasonal frost action caused most of the ensuing stability problems.Unusually warm summers and the lengths of time required to re-freeze the active layer were far more important than the average annual air temperatures in determining the temperatures of the underlying shallow permafrost,or the development of taliks.The hypothesized climate warming would slightly and gradually deepen the active layer and the developed under-lying talik,but its effect would be obscured by unusually warm summers,by warmer than usual winters,and by the vari-able lengths of time of the zero curtains.At least one period of climate mini-cooling in the deeper permafrost during the early 20th century was noted.

  17. Soil tillage erosion estimated by using magnetism of soils--a case study from Bulgaria.

    Jordanova, Diana; Jordanova, Neli; Atanasova, Anna; Tsacheva, Tsenka; Petrov, Petar

    2011-12-01

    A detailed field and laboratory study on small 0.84-ha test site of agricultural land near Sofia (Bulgaria) has been carried out in order to test the applicability of magnetic methods in soil erosion estimation in the particular case of strongly magnetic parent material. Field measurements of magnetic susceptibility were carried out with grid size of 6 m, resulting in 258 data points. Bulk soil material was gathered from 78 grid points. Natural, non-disturbed soil section was sampled near the agricultural field for reference profile of complete undisturbed soil. Surface susceptibility measurements reveal well-defined maxima down slope which, however, cannot be assigned directly to a certain depth interval, corresponding with susceptibilities along the non-disturbed soil profile. This is caused by the high magnetic susceptibility of the lithogenic coarse-grained magnetic fraction. Non-uniqueness is resolved by using magnetic susceptibility of coarse (1 mm > d > 63 μm) and fine (d soil profile, which corresponds to a certain part of the studied area. After the application of an empirical model to predict the values of magnetic parameter after tillage homogenization and removal of soil material from the surface, the amount of soil loss is estimated.

  18. Physically-Based Shallow Landslide Susceptibility Mapping, NW of Portugal

    Teixeira, Manuel; Bateira, Carlos; Soares, Laura

    2013-04-01

    Two physically-based models - Shallow Landslide Stability Analysis (SHALSTAB) and Safety Factor (SF) - are applied in Serra da Peneda (northwest of Portugal) to evaluate shallow landslide susceptibility in Tibo drainage basin. This small basin is located in an area of granitic and metasedimentary substrate, covered by different types of surficial formations (weathering mantles and slope deposits). The application of the selected models requires the determination of a set of mechanical and hydrological parameters, and the use of high resolution topographic information to create an accurate DTM. To fulfill this goal we have applied the Shallow Landslide Stability Analysis (SHALSTAB) and the SF (Safety Factor) models. The shallow landslide area was inventoried on the field. The cohesion was assessed by back analysis and the other mechanical and hydrological soil parameters were assessed on the field survey. Several susceptibility scenarios were tested with SHALSTAB model. The best SHALSTAB scenario used to assess the susceptibility is achieved using the following parameters: cohesion (c) = 2000 N/m2, soil thickness (z) = 1,2 m, internal friction (?)=32o and soil weight (?s)=14,7 KN/m3. Shallow landslide susceptibility mapping using the SF model, was based on the cartography of the factors registered on the field survey and used the following parameters: cohesion (c) = 2000 - 6000 N/m2, soil thickness (z) =1,2 m, internal friction (?)=30 - 40o; soil volumic weight (?m) = 13,7 - 15,7 KN/m3 and Hydraulic conductivity = 0 - 3,9-03 kfs. SHALSTAB scenarios were validated by overlaying the shallow landslide area (scar concentration) and selected the better susceptibility modeling. The parameters used on the SF model applied spatially variable values registered in the field survey (using the superficial formation cartography). To validate the SF model we used the AUC (Area Under the Curve) method. The two models were compared by the scar concentration and landslide potential

  19. Description and evaluation of a surface runoff susceptibility mapping method

    Lagadec, Lilly-Rose; Patrice, Pierre; Braud, Isabelle; Chazelle, Blandine; Moulin, Loïc; Dehotin, Judicaël; Hauchard, Emmanuel; Breil, Pascal

    2016-10-01

    Surface runoff is the hydrological process at the origin of phenomena such as soil erosion, floods out of rivers, mudflows, debris flows and can generate major damage. This paper presents a method to create maps of surface runoff susceptibility. The method, called IRIP (Indicator of Intense Pluvial Runoff, French acronym), uses a combination of landscape factors to create three maps representing the susceptibility (1) to generate, (2) to transfer, and (3) to accumulate surface runoff. The method input data are the topography, the land use and the soil type. The method aims to be simple to implement and robust for any type of study area, with no requirement for calibration or specific input format. In a second part, the paper focuses on the evaluation of the surface runoff susceptibility maps. The method is applied in the Lézarde catchment (210 km2, northern France) and the susceptibility maps are evaluated by comparison with two risk regulatory zonings of surface runoff and soil erosion, and two databases of surface runoff impacts on roads and railways. Comparison tests are performed using a standard verification method for dichotomous forecasting along with five verification indicators: accuracy, bias, success ratio, probability of detection, and false alarm ratio. The evaluation shows that the susceptibility map of surface runoff accumulation is able to identify the concentrated surface runoff flows and that the susceptibility map of transfer is able to identify areas that are susceptible to soil erosion. Concerning the ability of the IRIP method to detect sections of the transportation network susceptible to be impacted by surface runoff, the evaluation tests show promising probabilities of detection (73-90%) but also high false alarm ratios (77-92%). However, a qualitative analysis of the local configuration of the infrastructure shows that taking into account the transportation network vulnerability can explain numerous false alarms. This paper shows that the

  20. Microbial response to increasing temperatures during winter in arable soils

    Lukas, Stefan; Potthoff, Martin; Joergensen, Rainer Georg

    2014-05-01

    Climate scenarios predict increasing temperatures and higher precipitation rates in late fall to early spring, both holding the potential to modify carbon and nutrient dynamics in soils by altering snow pack thickness and soil frost events. When soils are frozen, a small amount of unfrozen water allows microorganisms to remain active at temperatures down to -10 °C. We carried out a field experiment on the microbial use of maize straw. We compared soils of two different clay contents and used latitude as a proxy for climate. Microcosms with sieved soil were mixed with chopped maize leaf straw (C/N 17) at a rate of 1 mg C g-1 dry soil, un-amended microcosms served as control. Results indicated that C-mineralization rates were independent from clay content. However, the microbial use of maize derived nitrogen was only increased in the soil with 13% clay compared to 33% clay in the other soil. Microbial responses to climate changes can be expected to be very specific due to characteristics of the soil and/or the location.

  1. Network susceptibilities: Theory and applications

    Manik, Debsankha; Rohden, Martin; Ronellenfitsch, Henrik; Zhang, Xiaozhu; Hallerberg, Sarah; Witthaut, Dirk; Timme, Marc

    2017-01-01

    We introduce the concept of network susceptibilities quantifying the response of the collective dynamics of a network to small parameter changes. We distinguish two types of susceptibilities: vertex susceptibilities and edge susceptibilities, measuring the responses due to changes in the properties of units and their interactions, respectively. We derive explicit forms of network susceptibilities for oscillator networks close to steady states and offer example applications for Kuramoto-type phase-oscillator models, power grid models, and generic flow models. Focusing on the role of the network topology implies that these ideas can be easily generalized to other types of networks, in particular those characterizing flow, transport, or spreading phenomena. The concept of network susceptibilities is broadly applicable and may straightforwardly be transferred to all settings where networks responses of the collective dynamics to topological changes are essential.

  2. Susceptibility to anchoring effects

    Todd McElroy

    2007-02-01

    Full Text Available Previous research on anchoring has shown this heuristic to be a very robust psychological phenomenon ubiquitous across many domains of human judgment and decision-making. Despite the prevalence of anchoring effects, researchers have only recently begun to investigate the underlying factors responsible for how and in what ways a person is susceptible to them. This paper examines how one such factor, the Big-Five personality trait of openness-to-experience, influences the effect of previously presented anchors on participants' judgments. Our findings indicate that participants high in openness-to-experience were significantly more influenced by anchoring cues relative to participants low in this trait. These findings were consistent across two different types of anchoring tasks providing convergent evidence for our hypothesis.

  3. Topological Susceptibility from Slabs

    Bietenholz, Wolfgang; Gerber, Urs

    2015-01-01

    In quantum field theories with topological sectors, a non-perturbative quantity of interest is the topological susceptibility chi_t. In principle it seems straightforward to measure chi_t by means of Monte Carlo simulations. However, for local update algorithms and fine lattice spacings, this tends to be difficult, since the Monte Carlo history rarely changes the topological sector. Here we test a method to measure chi_t even if data from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as slabs. Assuming a Gaussian distribution of these charges, this method enables the evaluation of chi_t, as we demonstrate with numerical results for non-linear sigma-models.

  4. Colloid Release From Differently Managed Loess Soil

    Vendelboe, Anders Lindblad; Schjønning, Per; Møldrup, Per

    2012-01-01

    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......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 Lauchsta¨dt longterm 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...

  5. Soil temperature triggers the onset of photosynthesis in Korean pine.

    Wu, Jiabing; Guan, Dexin; Yuan, Fenhui; Wang, Anzhi; Jin, Changjie

    2013-01-01

    In forest ecosystems, the onset of spring photosynthesis may have an important influence on the annual carbon balance. However, triggers for the onset of photosynthesis have yet to be clearly identified, especially for temperate evergreen conifers. The effects of climatic factors on recovery of photosynthetic capacity in a Korean pine forest were investigated in the field. No photosynthesis was detectable when the soil temperature was below 0 °C even if the air temperature was far beyond 15 °C. The onset of photosynthesis and sap flow was coincident with the time of soil thawing. The rates of recovery of photosynthetic capacity highly fluctuated with air temperature after onset of photosynthesis, and intermittent frost events remarkably inhibited the photosynthetic capacity of the needles. The results suggest that earlier soil thawing is more important than air temperature increases in triggering the onset of photosynthesis in Korean pine in temperate zones under global warming scenarios.

  6. A Computational Model of Water Migration Flux in Freezing Soil in a Closed System

    裘春晗

    2005-01-01

    A computational model of water migration flux of fine porous soil in frost heave was investigated in a closed system. The model was established with the heat-mass conservation law and from some previous experimental results. Through defining an auxiliary function an empirical function in the water migration flux, which is difficult to get, was replaced. The data needed are about the water content along the soft colunm after test with enough long time. We adopt the test data of sample soil colunms in [1] to verify the model. The result shows it can reflect the real situation on the whole.

  7. 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

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

    2011-04-15

    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

  8. Association mapping for frost tolerance using multi-parent advanced generation inter-cross (MAGIC) population in faba bean (Vicia faba L.).

    Sallam, Ahmed; Martsch, Regina

    2015-08-01

    A multi-parent advanced generation inter-cross (MAGIC) derived from 11 founder lines in faba bean was used in this study to identify quantitative trait loci (QTL) for frost tolerance traits using the association mapping method with 156 SNP markers. This MAGIC population consists of a set of 189 genotypes from the Göttingen Winter Bean Population. The association panel was tested in two different experiments, i.e. a frost and a hardening experiment. Six morphological traits, leaf fatty acid composition, relative water content in shoots were scored in this study. The genotypes presented a large genetic variation for all traits that were highly heritable after frost and after hardening. High phenotypic significant correlations were established between traits. The principal coordinates analysis resulted in no clear structure in the current population. Association mapping was performed using a general linear model and mixed linear model with kinship. A False discovery rate of 0.20 (and 0.05) was used to test the significance of marker-trait association. As a result, many putative QTLs for 13 morphological and physiological traits were detected using both models. The results reveal that QTL mapping by association analysis is a powerful method of detecting the alleles associated with frost tolerance in the winter faba bean which can be used in accelerating breeding programs.

  9. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak ( Quercus robur) in northern Poland?

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P.

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  10. A quantitative and constraint-specific method to assess the potential impact of new agricultural technology : the case of frost resistant potato for the Altiplano (Peru and Bolivia)

    Hijmans, R.J.; Condori, B.; Carrillo, R.; Kropff, M.J.

    2003-01-01

    A quantitative and constraint-specific approach to assess the potential impact of new agricultural technology is described and applied to frost resistant potato cultivars for the Altiplano (Peru and Bolivia). The approach uses geo-referenced databases and a simulation model. Calculations are made fo

  11. Study on frost resistance and anti-permeability of carbon nanotubes shotcrete%页岩陶粒混凝土冻融试验研究

    潘婷婷; 王彦伟

    2014-01-01

    The frost resistance of fiber and non-fiber concrete were experimentally studied respectively and compared analysis were made with plain ceramic concrete, steel fiber imitation ceramic concrete, steel fiber ceramic concrete, polypropylene ceramic concrete. Results showed that the performance of polypropylene fiber concrete frost are far superior to the other groups;frost resistance of steel fiber reinforced concrete than plain ceramic concrete;imitation ceramic steel fiber reinforced concrete and plain ceramic concrete did not improve its frost resistance.%分别对纤维类与非纤维类混凝土的抗冻性能进行了试验研究,并将其与素陶粒混凝土、仿钢纤维陶粒混凝土、钢纤维陶粒混凝土、聚丙烯陶粒混凝土进行了比较分析,结果表明:聚丙烯纤维混凝土的抗冻性能均远远优于其他各组;钢纤维混凝土的抗冻性能优于素陶粒混凝土;仿钢纤维陶粒混凝土与素陶粒混凝土并没有改善其抗冻性能。

  12. Numerical analysis of the impact of charcoal production on soil hydrological behavior, runoff response and erosion susceptibility Investigação numérica/quantitativa sobre o impacto do processo de produção de carvão nas propriedades hidráulicas, resposta ao deflúvio e suscetibilidade do solo à erosão

    Ajayi Ayodele

    2009-02-01

    Full Text Available The impact of charcoal production on soil hydraulic properties, runoff response and erosion susceptibility were studied in both field and simulation experiments. Core and composite samples, from 12 randomly selected sites within the catchment of Kotokosu were taken from the 0-10 cm layer of a charcoal site soil (CSS and adjacent field soils (AFS. These samples were used to determine saturated hydraulic conductivity (Ksat, bulk density, total porosity, soil texture and color. Infiltration, surface albedo and soil surface temperature were also measured in both CSS and AFS. Measured properties were used as entries in a rainfall runoff simulation experiment on a smooth (5 % slope plot of 25 x 25 m grids with 10 cm resolutions. Typical rainfall intensities of the study watershed (high, moderate and low were applied to five different combinations of Ks distributions that could be expected in this landscape. The results showed significantly (p O impacto do processo de produção de carvão nas propriedades hidráulicas, a resposta ao deflúvio e a suscetibilidade do solo à erosão foram estudados em experimentos de campo e de simulação. Amostras indeformadas e compostas de 12 locais aleatoriamente selecionados dentro do reservatório de Kotokosu foram coletadas na camada de 0-10 cm no solo sob carvão (CSS e no solo adjacente (AFS. Essas amostras foram usadas para determinar a condutividade hidráuli7ca saturada (Ksat, densidade do solo, porosidade total, textura e cor do solo. A infiltração, o albedo de superfície e a temperatura de superfície do solo também foram medidos no CSS e AFS. Os parâmetros medidos foram usados como entrada nos experimentos de simulação de deflúvio em uma parcela uniforme (5 % de declividade de 25 x 25 m, com grides de 10 cm de resolução. Altas, moderadas e baixas intensidades de chuva, típicas da bacia em estudo, foram aplicadas em cinco diferentes combinações de Ksat, que poderiam ser esperadas nessa

  13. Design and Construction of Foundations in Areas of Deep Seasonal Frost and Permafrost.

    1980-08-01

    scientific research, especially the Division of Building Research of the National Research Council of Canada. Pertinent literature, experience records, and...and soils in which segregated ice is visible. The visual division is not necessarily determinative for thaw settlement potential. The boundaries...conditions. 96 .’,’ __________ -_ -- ."- ’ .. : , -. - -i , . .* ,. : . .. . , ,; .. .. ,,.: .’ . .- . : S aM O dPae 4 " Celular Glow ! _ . IoI¢ P

  14. Green house gas flux at high latitudes - constraints and susceptibility to a changing climate

    Nilsson, M. B.

    2015-12-01

    High latitude boreal forests and peatlands contribute importantly to the land-atmosphere exchange of both carbon dioxide and methane. High latitude biomes are also identified as most vulnerable to changing climate. High latitudes are characterized by a strong seasonality in incoming solar radiation, weather conditions and biogeochemical processes. The strong seasonality in incoming solar radiation, not to change in response to a changing climate, constitute firm constraints on how changes in air temperature, evapotranspiration and precipitation will affect biogeochemical processes underlying the land atmosphere exchange of green house gases. Timing of the soil frost thaw and plant phenology thus constitutes two master controls on how fluxes of both CO2 and CH4 will be affected by weather conditions. In addition also the wintertime conditions importantly affect GHG fluxes both during winter time as well as during the succeeding summer. Examples will primarily be given for peatlands and coniferous forests.

  15. Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event

    M. K. Pihlatie

    2009-06-01

    Full Text Available Fluxes of greenhouse gases (GHG carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O were measured during a two month campaign at a drained peatland forest in Finland by the eddy covariance (EC technique (CO2 and N2O, and automatic and manual chambers (CO2, CH4 and N2O. In addition, GHG concentrations and soil parameters (mineral nitrogen, temperature, moisture content in the peat profile were measured. The aim of the measurement campaign was to quantify the GHG fluxes before, during and after thawing of the peat soil, a time period with potentially high GHG fluxes, and to compare different flux measurement methods. The forest was a net CO2 sink during the two months and the fluxes of CO2 dominated the GHG exchange. The peat soil was a small sink of atmospheric CH4 but a small source of N2O. Both CH4 oxidation and N2O production took place in the top-soil whereas CH4 was produced in the deeper layers of the peat. During the thawing of the peat distinct peaks in CO2 and N2O emissions were observed. The CO2 peak followed tightly the increase in soil temperature, whereas the N2O peak occurred with an approx. one week delay after soil thawing. CH4 fluxes did not respond to the thawing of the peat soil. The CO2 and N2O emission peaks were not captured by the manual chambers and hence we conclude that automatic chamber measurements or EC are necessary to quantify fluxes during peak emission periods. Sub-canopy EC measurements and chamber-based fluxes of CO2 and N2O were comparable, although the fluxes of N2O measured by EC were close to the detection limit of the EC system. We conclude that if fluxes are high enough, i.e. greater than 5–10 μg N m−2 h−1

  16. Role of planting stock size and fertilizing in initial growth performance of rowan (Sorbus aucuparia L. reforestation in a mountain frost hollow

    Ivan Kuneš

    2014-08-01

    Full Text Available The aim of study: (1 to compare the survival rate, growth performance and nutrition of large and common-sized planting stock of rowan (Sorbus aucuparia L. on a frost-exposed site and (2 to assess whether fertilizing had any effect on the plantations.Area of study: The Jizera Mts., an area heavily disturbed by air pollution situated on the Czech-Polish border close to GermanyMaterials and methods: Two types of planting stock were tested in a mountain frost hollow on an acidic mountain humic podsol: (a the bare-rooted saplings 131–140 cm tall and (b common-sized containerized transplants 26–35 cm. One half of the saplings and common-sized transplants were left untreated and the other half were fertilized with a low dose (30 g per tree of a slow release fertilizer based on methylene urea and potassium magnesium phosphate. Growth performance and nutrition of plantations were investigated.Main results: Due to serious deformations and stem breakages inflicted by snow and frost, the prospects of common-sized transplants seem much worse than those of saplings. The height growth of saplings was significantly more rapid than that of common-sized transplants. As for growth, neither the saplings nor common-sized transplants did significantly respond to fertilizing. The effects of fertilizing on nutrition of rowans were unconvincing. The extreme temperature events during growth seasons and snow deformations in winters might be the decisive factors influencing growth performance of rowans under referred conditions.Research highlights: On the frost-exposed sites, the height of taller saplings might partly compensate for a missing shelter of forest stand since the terminal leaders are above ground-frost zone.Key words: mountain ash; sapling; common-sized transplants; nutritional status; temperature.Abbreviations: CS – Control Saplings; CT – Control Transplants; FS – Fertilized Saplings; FT – Fertilized Transplants

  17. Transformation functions of soil color and climate

    杨胜利; 方小敏; 李吉均; 安芷生; 陈诗越; HitoshiFukusawa

    2001-01-01

    Measurements on modern soil color suggest well functional relationships between the soil formation process and the present climatic factors. The redness and yellowness of soil are chiefly caused by the contents of hematite and fullonite, and their correlations to climate are the best in humid regions in tropic and warm temperate regions. The lightness of soil mainly correlates to the organic accumulation, humification and carbonatization processes, and its correlation to climate can only be found in the humid-arid extratropical belt. The humidity and surface roughness of soil have so strong influence on soil color that there are great errors on the measurement of colorness in the field. The study on soil colors of typical loess sections shows that soil color can record the characteristics of Asia monsoon and the global climatic fluctuations well at millennial and ten-thousand-year scales. It can also indicate the pedogenesis and the climatic characteristics which magnetic susceptibility could not be refl

  18. Cold season soil NO fluxes from a temperate forest: drivers and contribution to annual budgets

    Medinets, S.; Gasche, R.; Skiba, U.; Schindlbacher, A.; Kiese, R.; Butterbach-Bahl, K.

    2016-11-01

    Soils, and here specifically acidic forest soils exposed to high rates of atmospheric nitrogen deposition, are a significant source for the secondary greenhouse gas nitric oxide (NO). However, as flux estimates are mainly based on measurements during the vegetation period, annual NO emissions budgets may hold uncertainty as cold season soil NO fluxes have rarely been quantified. Here we analyzed cold season soil NO fluxes and potential environmental drivers on the basis of the most extensive database on forest soil NO fluxes obtained at the Höglwald Forest, Germany, spanning the years 1994 to 2010. On average, the cold season (daily average air temperature soil NO budget, varying from 13% to 41% between individual cold seasons. Temperature was the main controlling factor of the cold season NO fluxes, whereas during freeze-thaw cycles soil moisture availability determined NO emission rates. The importance of cold season soil NO fluxes for annual NO fluxes depended positively on the length of the cold season, but responded negatively to frost events. Snow cover did not significantly affect cold season soil NO fluxes. Cold season NO fluxes significantly correlated with cold season soil carbon dioxide (CO2) emissions. During freeze-thaw periods strong positive correlations between NO and N2O fluxes were observed, though stimulation of NO fluxes by freeze-thaw was by far less pronounced as compared to N2O. Except for freeze-thaw periods NO fluxes significantly exceeded those for N2O during the cold season period. We conclude that in temperate forest ecosystems cold season NO emissions can contribute substantially to the annual NO budget and this contribution is significantly higher in years with long lasting but mild (less frost events) cold seasons.

  19. Intercropping frost-sensitive legume crops with winter oilseed rape reduces weed competition, insect damage, and improves nitrogen use efficiency

    Cadoux Stéphane

    2015-05-01

    Full Text Available Mixing plant species in agroecosystems is highlighted as an agroecological solution to reduce pesticides and fertilizers while maintaining profitability. In the French context, intercropping frost-sensitive legume crops with winter oilseed rape is potentially interesting and began to be implemented by farmers. In this study we aimed at measuring the services and disservices of this intercrop with three different legume mixtures, in terms of growth and yield for rapeseed, ground cover of weeds in autumn and damage caused by rape winter stem weevil. The experiment was carried out at four sites from 2011 to 2014. We showed higher total aerial dry weights and total aerial nitrogen contents in the intercrops compared to sole winter oilseed rape in November. The companion plants contributed to the control of weeds and the mitigation of rape winter stem weevil damage, notably through the increase in the total aerial weight. In spring, after destruction of the companion plants, the intercrops had partially compensated a reduction in the N fertilization rate (–30 kg per hectare in terms of aerial nitrogen content in rapeseed, with no consequences on the yield which was maintained or even increased. There were probably other interactions such as an improvement in rapeseed root exploration. The consequences were an increase in the nitrogen use efficiency in intercrops. The intercrop with faba bean and lentil showed the best results in terms of autumn growth, weed control, reduction in rape winter stem weevil damage, and rapeseed N content in spring and yield. Intercropping frost-sensitive legume crops with winter oilseed rape is thus a promising way to reconcile yield and reduction in pesticides and fertilizer use and perhaps to benefit more widely to the cropping system.

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

    R. Mortazavi

    2014-12-01

    Full Text Available 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.

  1. FLOOD SUSCEPTIBILITY ASSESSMENT IN THE NIRAJ BASIN

    SANDA ROŞCA

    2012-03-01

    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.

  2. Hydrocarbon contamination increases the liquid water content of frozen Antarctic soils.

    Siciliano, Steven D; Schafer, Alexis N; Forgeron, Michelle A M; Snape, Ian

    2008-11-15

    We do not yet understand why fuel spills can cause greater damage in polar soils than in temperate soils. The role of water in the freezing environment may partly be responsible for why polar soils are more sensitive to pollution. We hypothesized that hydrocarbons alter the liquid water in frozen soil, and we evaluated this hypothesis by conducting laboratory and field experiments at Casey Station, Antarctica. Liquid water content in frozen soils (theta(liquid)) was estimated by time domain reflectometry in laboratory, field collected soils, and in situ field measurements. Our results demonstrate an increase in liquid water associated with hydrocarbon contamination in frozen soils. The dependence of theta(liquid) on aged fuel and spiked fuel were almost identical,with a slope of 2.6 x 10(-6) mg TPH (total petroleum hydrocarbons) kg(-1) for aged fuel and 3.1 x 10(-6) mg TPH kg(-1) for spiked fuel. In situ measurements found theta(liquid) depends, r2 = 0.75, on fuel for silt loam soils (theta(liquid) = 0.094 + 7.8 x 10(-6) mg TPH kg(-1)) but not on fuel for silt clay loam soils. In our study, theta(liquid) doubled in field soils and quadrupled in laboratory soils contaminated with diesel which may have profound implications on frost heave models in contaminated soils.

  3. The effect of chloride fertilization on blackspot susceptibility and other quality characteristics and on yield of potato

    Loon, van C.D.; Berg, van den W.

    2004-01-01

    Trials were carried out in two years on a sandy loam and on a heavy clay soil with two cultivars to examine the potential of chloride fertilization as a tool to reduce blackspot susceptibility of potatoes and to investigate other effects on yield and quality. Blackspot susceptibility was significant

  4. [Antimicrobial susceptibility in Chile 2012].

    Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime

    2014-04-01

    Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

  5. Change Laws of Frost-free Period and Its Impact on Agriculture in Linjiang%临江市无霜期变化规律及其对农业的影响

    于文立; 杨琦

    2012-01-01

    采用气候统计学方法,对临江市1961 ~2010年初、终霜日及无霜期气候特征进行分析.结果表明:临江市初霜日明显延后,气候倾向率达2.43 d/10a;终霜日也有明显提前趋势,气候倾向率仅为-2.16d/10a,主要受初霜日延后的影响,临江市无霜期明显增加,气候倾向率为4.4d/10a;临江市初终霜、无霜期年代特征明显;经突变分析,临江市无霜期变化存在明显的转折年;临江市利用无霜期长短调整了作物品种布局,取得显著经济效益.%Using the climatic statistics method,the climatic characteristics of first frost,last frost and frost-free period in Unjiang City from 1961 to 2010 were analzyed. The results showed that the first frost date of Linjiang City delayed obviously with a climatic trend rate of 2.43 d/10a; while the last frost date advanced with a climatic trend rate of only -2.16 d/ 10a. Under the influence of delayed first frost date,the frost-free period increased obviously with a climatic trend rate of 4.4 d/10a; the first frost,last frost and frost-free period of Linjiang City were characterized by obvious decadal features. Through mutation analysis,the frost-free period of Linjiang had obvious turning point. The adjustment of crop cultivars layout according to the length of frost-free period achieved remarkable economic benefits.

  6. Soils - NRCS Web Soil Survey

    NSGIC GIS Inventory (aka Ramona) — Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation...

  7. Overview of different aspects of climate change effects on soils.

    Qafoku, Nikolla

    2014-08-01

    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.

  8. Overview of different aspects of climate change effects on soils

    Qafoku, Nikolla P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-08-01

    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.

  9. 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

    Escobar T. William

    1992-12-01

    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.

  10. 环境参数对空气源热泵蒸发器表面霜层影响研究%Effect of Environmental Condition on Evaporator Surface Frost Layer for Air Source Heat Pump

    郭宪民; 王善云; 汪伟华; 陈纯正

    2011-01-01

    对一台空气源热泵翅片管蒸发器表面结霜特性进行了实验研究,分析了室外环境温度和相对湿度对霜层的形态、平均密度、总平均密度及动态密度的影响.实验结果表明:室外环境温度的降低或相对湿度的增加将促使换热器表面霜层在生长过程中形成针状霜晶,乃至形成绒状霜层;在高温、高湿度工况下,霜层表面出现凝结水滴,使得霜层密度增大.在霜层减速生长段,霜层平均密度随结霜时间呈增大趋势,而在霜层加速生长段,霜层平均密度随结霜时间迅速减小,且动态霜层密度远远小于霜层平均密度.对环境参数不同而霜层厚度相同的霜层平均密度进行比较发现,其随环境温度的升高及相对湿度的减小而增大,且相对湿度的影响在低湿度工况下更为显著.%The frosting characteristics on the surface of the fin-tube evaporator of an air source heat pump (ASHP) were experimentally investigated.The effects of the outdoor air temperature and humidity on the frost morphology and the average density, total average density, and dynamic density of the frost layer were analyzed.The experimental results indicate that the decrease in the outdoor air temperature or the increase in the relative humidity results in the formation of the acerose-shaped ice crystals, even of the fluffy frost layer on the evaporator surface of the ASHP.At higher air temperature and humidity, the average frost density rises clearly due to the existence of the water droplet on the frost layer surface.In the deceleration stage of the frost growth,the average frost density increases with the frosting time.In the acceleration stage of the frost growth, the average frost density decreases rapidly with the increase in the frosting time and the dynamic frost density is much lower than the average density of the frost layer.The comparison between the average frost densities at the same frost layer thickness under different

  11. Genetic diversity and disease susceptibility.

    Bodmer, W F

    1997-01-01

    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...

  12. Monitor Soil Degradation or Triage for Soil Security? An Australian Challenge

    Andrea Koch

    2015-04-01

    Full Text Available The Australian National Soil Research, Development and Extension Strategy identifies soil security as a foundation for the current and future productivity and profitability of Australian agriculture. Current agricultural production is attenuated by soil degradation. Future production is highly dependent on the condition of Australian soils. Soil degradation in Australia is dominated in its areal extent by soil erosion. We reiterate the use of soil erosion as a reliable indicator of soil condition/quality and a practical measure of soil degradation. We describe three key phases of soil degradation since European settlement, and show a clear link between inappropriate agricultural practices and the resultant soil degradation. We demonstrate that modern agricultural practices have had a marked effect on reducing erosion. Current advances in agricultural soil management could lead to further stabilization and slowing of soil degradation in addition to improving productivity. However, policy complacency towards soil degradation, combined with future climate projections of increased rainfall intensity but decreased volumes, warmer temperatures and increased time in drought may once again accelerate soil degradation and susceptibility to erosion and thus limit the ability of agriculture to advance without further improving soil management practices. Monitoring soil degradation may indicate land degradation, but we contend that monitoring will not lead to soil security. We propose the adoption of a triaging approach to soil degradation using the soil security framework, to prioritise treatment plans that engage science and agriculture to develop practices that simultaneously increase productivity and improve soil condition. This will provide a public policy platform for efficient allocation of public and private resources to secure Australia’s soil resource.

  13. Antimicrobial susceptibility and susceptibility testing of Mycoplasma hominis: a review.

    Bygdeman, S M; Mårdh, P A

    1983-01-01

    The determination of the minimal growth-inhibiting concentration (MIC), the minimal metabolism-inhibiting concentration (MMC), and the minimal mycoplasmacidal concentration (MCC) of various antimicrobial compounds for Mycoplasma hominis is influenced by the pH of the test media, the inoculum size, and the incubation time, although each of these factors generally do not affect the minimal concentration more than fourfold. M. hominis is resistant to beta-lactam antibiotics, vancomycin, sulfonamides, trimethoprim, and polymyxin B. There are great differences in the susceptibility of M. hominis to various macrolide antibiotics. Thus the organism is resistant to erythromycin and oleandomycin, moderately resistant to tylosin and spiramycin, susceptible to josamycin as well as to another macrolide drug, labelled M-4365G. M. hominis is also highly susceptible to the macrolide-like compound rosaramicin and to the tetracyclines (although resistant strains occur). It is susceptible to lincomycin and clindamycin, and moderately susceptible to chloramphenicol and rifampicin. The aminoglycosides have limited activity against M. hominis.

  14. U.S.V.I. Soil Erodibility (Kffact)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S.V.I. soil erodibility (Kffactor) - low values indicate low vulnerability to erosion, higher values mean higher susceptibility to runoff.

  15. Experimental study on grain size and soluble salt of saline soil in western Jilin Province, China

    TianWen Yu; Qing Wang; XuDong Zhang; Xin Zhou; Gang Wang; CenCen Niu

    2015-01-01

    Western Jilin Province is a typical seasonal frost region, and is also one of the severest salinization areas of China. In this study, we aim to examine the saline soil in Da'an and Wukesong areas, western Jilin Province, and mainly analyze the granulometric composition and distribution of salt in soil profiles. Four sampling sites, two in Da'an and two in Wukesong respectively, are chosen for study. The granulometric composition, especially silt and clay content change in different sites and soil depths are analyzed. Analysis of total and components of soluble salt shows that the surface soil is weak carbonate saline, in which the main cation is Na+and the main anion is HCO3−. The total amount of soluble salt presents a decreasing tendency with increasing depth. The comprehensive analysis of granulometric composition and soluble salt shows that the clay content and soluble salt content present similar variation tendency with an increase of depth.

  16. Responses in gas exchange and water status between drought-tolerant and-susceptible soybean genotypes with ABA application

    Md.Mokter Hossain; Hon-Ming Lam; Jianhua Zhang

    2015-01-01

    The purpose of this study was to investigate the physiological responses of drought-tolerant and drought-susceptible soybean genotypes to exogenous abscisic acid(ABA) application during progressive soil drying at seedling stages. Five-day old soybean seedlings were transplanted into PVC tubes filled with soil mixture. Seedlings were watered daily with similar water volumes until second trifoliate leaves emerged, and thereafter soil drying with or without exogenous ABA application was imposed. Half of the seedlings of each genotype were left for regular watering as control plants. Soil water status declined significantly over seven days of withholding water supply for both genotypes. Leaf expansion rate, stomatal conductance(g_s), leaf water potential(ψ_w), and relative water content of leaves(%RWC) declined significantly under soil drying as well as soil drying with ABA application, compared to their values for well-watered soybean genotypes. However, a drought-tolerant genotype(C12) responded more rapidly than a drought-susceptible genotype(C08) after imposition of soil drying and soil drying with exogenous ABA. In addition, application of exogenous ABA to water-restricted soybeans resulted in higher %RWC and ψwin the drought-tolerant than in the drought-susceptible genotype. Compared to the drought-susceptible genotype, the drought-tolerant genotype was more responsive to exogenous ABA application, resulting in a higher root-to-shoot ratio.

  17. Response of Frost to Temperature and Precipitation Changes in Recent 30 Years in Qinghai Province%青海近30年来霜对气温、降水变化的响应

    祁如英; 李应业; 汪青春

    2011-01-01

    The frost phenophase was anaylysed with linear trend and single correlation method by using meteoro-logical data from 33 weather stations in Qinghai Plateau. Results show that the variation trends of first frost and lat-est frost present regional features of delay and ahead of schedule, respectively. On the interdecadal scale, first frost was delayed while latest frost was advanced and frost-free period was extended obviously in most regions. In a few areas, a negative correlation existed between latest frost with air temperature, and a positive correlation with precip-itation. In some areas, a positive correlation existed between first frost with air temperature, and had no obvious re-sponses to precipitation. In most areas, a positive correlation existed between frost-free period with air temperature and precipitation. The comprehensive response of first frost and latest frost to climate change showed that the ex-tened variation trends have obvious regional differences.%用线性趋势和单相关法分析了青海高原33个气象站的霜物候期及气象资料,结果表明:青海高原1978~2007年初霜、终霜变化趋势存在明显推迟、提早的区域性特征.在年代际尺度上,初霜大部分地区明显推迟,终霜大部分地区明显提早,无霜期绝大部分地区明显延长.少部分地区终霜对气温负相关显著,对降水正相关显著.部分地区初霜对气温正相关显著,绝大部分地区初霜对降水略呈增多变化响应不明显.大部分地区无霜期对气温为正相关显著,且对气温的响应比对降水的明显;初霜、终霜对气候变化的综合响应表现在无霜期的延长变化趋势存在明显的区域性差异.

  18. A complicated story of frost and wind: Present-day gully activity within the north polar erg, Mar

    Diniega, Serina; Hansen, Candice; Allen, Amanda; Grisby, Nathan; Li, Zheyu Joey

    2016-10-01

    Analyses of high-resolution observations have shown that the dunes within the martian north polar erg (AKA Olympia Undae) are currently very active on seasonal and yearly timescales, with 20-60% of the dunes within five polar dune fields undergoing the formation of alcove-apron features each Mars year. Previous studies have hypothesized formation mechanisms, based on observations of when new alcove and alcove-apron features form within an individual field through one Mars year. However, results are ill-constrained (and thus different hypotheses have been proposed) as the polar hood and winter night mean very few images are taken during the actual period of activity. In this study, we mitigate this limitation by examining several fields over several Mars years -- thus bringing aggregated results as well as detailed correlation checks against environmental conditions and seasonal processes to bear on the problem. From this, we propose a new process that appears consistent with all observations: (1) small alcoves form along the dune brink in the autumn (under the polar hood) due to instabilities induced by the night-formation and morning-sublimation of frost. As autumn progresses, the seasonal frost layer builds over the altered dune slope. (2) In the early spring, sublimation activity is concentrated and/or enhanced over these alcoves, causing further erosion and the formation of larger alcove-apron features. From the planform dimensions of the newly formed alcoves, we can estimate the volume of sand moved down the dune slope during one period of activity and estimate the aeolian sediment flux by looking at how quickly the alcoves are erased. We find that, over a Mars year, the amount of material moved via alcove-apron activity and via the wind are both comparable to aeolian sand flux estimates over dunes within lower-latitude regions of Mars. Thus it appears that the formation of alcoves-aprons is a significant mechanism for dune advancement and evolution within the

  19. Simultaneous Inhibition of Linolenic Acid Synthesis in Winter Wheat Roots and Frost Hardening by BASF 13-338, a Derivative of Pyridazinone.

    Willemot, C

    1977-07-01

    Treatment of 12-day-old winter wheat (Triticum aestivum) plants with BASF 13-338 {4-chloro-5 (dimethylamino)-2-phenyl-3(2H)-pyridazinone} 36 hours before frost hardening simultaneously and completely inhibits accumulation of linolenic acid in the roots during the hardening period and the acquisition of frost resistance. Increased unsaturation of fatty acids is therefore probably an important part of the mechanism of cold adaptation in winter wheat.BASF 13-338 also prevents the increase in per cent dry weight in roots and shoots during hardening and causes a decrease in root lipid phosphorus and total fatty acids.The concurrent increase in linoleic acid and decrease in linolenic acid in the treated plants, while the level of the other fatty acids is but little affected, suggest that BASF 13-338 specifically inhibits linoleic acid desaturase.

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

    Morabia, Alfredo

    2013-10-01

    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.

  1. Formation and Defense of Frost Disaster in Hongyuan Region%红原地区霜冻灾害的形成和防御

    李发军

    2015-01-01

    霜冻给红原牧草及农作物的生长发育带来严重危害,是造成牧草及农作物减产的主要因素,故首先介绍霜冻的形成机理,并提出霜冻防御措施,如采用覆盖法、烟熏法、灌水法,及一些农业措施。%Frost disaster brings seri-ous harm to the growth of forage and crops,which is the main factors leading to forage and crops loss.So the frost for-mation mechanism was introduced at first,then defense measures were put for-ward,including covering method,smoking method,watering method,and some agri-cultural measures.

  2. 路基中翻浆现象的发生及处理措施%On frost boiling in roadbeds and its treatment measures

    陈晓强

    2011-01-01

    结合近几年工程施工实践,简要分析了影响路基发生翻浆的因素,在此基础上提出了防治和处理翻浆的相关措施,以避免翻浆这一普遍现象的发生,保证道路工程质量。%Combining with the construction practice in recent years,the paper analyzes the factors which influence the frost boiling,and points out the prevention and treatment measures,so as to avoid the frost boiling,which is considered to be common in roadbeds,and to ensure the quality of road projects.

  3. Experimental analysis and prediction for aircraft ground frosting based on sensor%基于传感器的飞机地面结霜实验分析与预测

    王立文; 孙闯; 陈斌

    2015-01-01

    The frosting of aircraft on the ground destroys aerodynamic shape and has a negative effect on the flight performance. In order to monitor and forecast on aircraft frosting on the ground accurately,experimental research on airfoil frosting is carried out using variety of sensors;by analyzing frost layer growth curve of simulating airfoil in different environment conditions,law of airfoil frosting is researched. Analyze datas of frosting experiment,propose polynomial regression predicting model in different frosting environments. Meanwhile,multicollinearity is avoided by orthogonalizing polynomials,which make prediction model has high curve fitting and high precision,fast and accurate prediction for ground frosting of aircrafts is realized.%飞机在地面的结霜会破坏飞机的气动外形,对飞机的飞行性能产生不利的影响。为了对地面飞机结霜进行准确监测与预测,利用多种传感器对机翼的结霜环境进行实验研究,通过分析不同环境下模拟机翼的霜层生长曲线,探寻和统计飞机机翼的地面结霜规律。对结霜实验的数据进行分析,提出了不同结霜环境下的多项式回归预测模型。同时将多项式进行正交化,避免了多重共线性,使预测模型的曲线拟合程度高,预测值具有较高的精度,实现了对飞机的地面结霜进行快速精确的预测。

  4. Susceptibility Genes in Thyroid Autoimmunity

    Yoshiyuki Ban

    2005-01-01

    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.

  5. Ice-lens formation and geometrical supercooling in soils and other colloidal materials

    Style, Robert W.

    2011-10-14

    We present a physically intuitive model of ice-lens formation and growth during the freezing of soils and other dense, particulate suspensions. Motivated by experimental evidence, we consider the growth of an ice-filled crack in a freezing soil. At low temperatures, ice in the crack exerts large pressures on the crack walls that will eventually cause the crack to split open. We show that the crack will then propagate across the soil to form a new lens. The process is controlled by two factors: the cohesion of the soil and the geometrical supercooling of the water in the soil, a new concept introduced to measure the energy available to form a new ice lens. When the supercooling exceeds a critical amount (proportional to the cohesive strength of the soil) a new ice lens forms. This condition for ice-lens formation and growth does not appeal to any ad hoc, empirical assumptions, and explains how periodic ice lenses can form with or without the presence of a frozen fringe. The proposed mechanism is in good agreement with experiments, in particular explaining ice-lens pattern formation and surges in heave rate associated with the growth of new lenses. Importantly for systems with no frozen fringe, ice-lens formation and frost heave can be predicted given only the unfrozen properties of the soil. We use our theory to estimate ice-lens growth temperatures obtaining quantitative agreement with the limited experimental data that are currently available. Finally we suggest experiments that might be performed in order to verify this theory in more detail. The theory is generalizable to complex natural-soil scenarios and should therefore be useful in the prediction of macroscopic frost-heave rates. © 2011 American Physical Society.

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

    Mark D Aurit

    Full Text Available 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.

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

    Li Yongle

    2011-10-01

    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.

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

    Jorge A Gatica

    2009-01-01

    Full Text Available 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.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 the 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.

  9. Ground-Penetrating-Radar Profiles of Interior Alaska Highways: Interpretation of Stratified Fill, Frost Depths, Water Table, and Thaw Settlement over Ice-Rich Permafrost

    2016-08-01

    main purpose of this report is to show that ground-penetrating radar (GPR) not only can detect the pres- ence of thaw settlement but also can reveal...ever published use of GPR was to detect massive ice in perma- frost (Bertram et al. 1972). Subsequently, GPR has been continually used to locate...information from boreholes is used to site buildings; but drilling is costly and time con- suming, and even tightly spaced drilling information can

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

    Evangelin Ramani Sujatha; G Victor Rajamanickam; P Kumaravel

    2012-10-01

    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.

  11. Variation Characteristics of Frost and Its Influence on Crops During 1961-2009 in Toli County%托里县1961-2009年霜冻变化特征及其对农作物的影响

    张延菊

    2014-01-01

    根据1961-2009年托里县地面气象观测实测资料,对当地霜冻变化特征进行分析。结果表明,托里县初霜日推迟、终霜日提前,无霜期延长,对农作物生长十分有利,但需要注意防范个别年份出现的初霜日提前、终霜日延后的灾害性天气。%Variation characteristics of frost were analyzed according to the ground meteorological observation data during 1961-2009 in Toli County. The results showed that the first frost date postponed and the latest frost date in advance,and the frost-free period ex-tended in Toli County,which was good for the growth of crops. But in individual years,we need to pay attention to pre-vention of the disastrous weather which the first frost date in advance and the latest frost date postponing.

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

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

    1981-01-01

    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.

  13. Magnetic Properties as Indicators of Cu and Zn Contamination in Soils

    LU Sheng-Gao; BAI Shi-Qiang; FU Li-Xia

    2008-01-01

    Concentrations of copper (Cu) and zinc (Zn) and various magnetic parameters in contaminated urban roadside soils were investigated using chemical analysis and magnetic measurements. The results revealed highly elevated Cu and Zn concentrations as well as magnetic susceptibility in the roadside soils. The mean concentrations of Cu and Zn in these roadside soils were almost twice those in average Chincsc soils, with the mean magnetic susceptibility of the roadside soils reaching about 179×10-8m3 kg-1. This enhanced magnetic susceptibility was attributed to the presence of anthro-pogcnic soft ferrimagnetic particles. A low frequency-dependent susceptibility (2.5%±1.0%) observed in the roadside soils indicated the coarse multidomain (MD) fcrrimagnetic grains to be the dominant contributor to magnetic susceptibility.The Cu and Zn concentration of the soils had highly significant linear correlations with magnetic susceptibility (P≤0.01),anhysterctic remanent magnetization (P≤0.01), and saturation isothermal remanent magnetization (P≤0.01). This suggested that heavy metals were associated with ferrimagnetic particles in soils, which were attributed to input of traffic emissions and industrial activities. Scanning electron microscopy and energy dispersive X-ray spectra of magnetic extracts of the roadside soils further suggested the link between the magnetic signal and concentrations of heavy metals. Thus, the magnetic parameters could provide a proxy measure for the level of heavy metal contamination and could be a potential tool for the detection and mapping of contaminated soils.

  14. Heck's disease: diagnosis and susceptibility.

    Bennett, Lindsey K; Hinshaw, Molly

    2009-01-01

    Focal epithelial hyperplasia, or Heck's disease, is an uncommon proliferation of oral mucosa that presents primarily in Native Central and South American populations. It presents as asymptomatic papules or nodules on the oral mucosa, gingiva, tongue, and lips. In the majority of cases, human papilloma virus 13 or 32 is detected. Factors that determine disease susceptibility are unclear, but genetics, and having the human lymphocytic antigen-DR4 (DRB1*0404) allele in particular, are thought to play a major role in disease vulnerability. We report another case of focal epithelial hyperplasia, hypothesize on disease susceptibility, and review the current understanding of this uncommon disorder.

  15. Susceptibility of Aeromonas Hydophila Isolates to Antimicrobial Drugs

    Igor Stojanov

    2010-05-01

    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

  16. Digital Image Sensor-Based Assessment of the Status of Oat (Avena sativa L.) Crops after Frost Damage

    Macedo-Cruz, Antonia; Pajares, Gonzalo; Santos, Matilde; Villegas-Romero, Isidro

    2011-01-01

    The aim of this paper is to classify the land covered with oat crops, and the quantification of frost damage on oats, while plants are still in the flowering stage. The images are taken by a digital colour camera CCD-based sensor. Unsupervised classification methods are applied because the plants present different spectral signatures, depending on two main factors: illumination and the affected state. The colour space used in this application is CIELab, based on the decomposition of the colour in three channels, because it is the closest to human colour perception. The histogram of each channel is successively split into regions by thresholding. The best threshold to be applied is automatically obtained as a combination of three thresholding strategies: (a) Otsu’s method, (b) Isodata algorithm, and (c) Fuzzy thresholding. The fusion of these automatic thresholding techniques and the design of the classification strategy are some of the main findings of the paper, which allows an estimation of the damages and a prediction of the oat production. PMID:22163940

  17. Digital Image Sensor-Based Assessment of the Status of Oat (Avena sativa L. Crops after Frost Damage

    Isidro Villegas-Romero

    2011-06-01

    Full Text Available The aim of this paper is to classify the land covered with oat crops, and the quantification of frost damage on oats, while plants are still in the flowering stage. The images are taken by a digital colour camera CCD-based sensor. Unsupervised classification methods are applied because the plants present different spectral signatures, depending on two main factors: illumination and the affected state. The colour space used in this application is CIELab, based on the decomposition of the colour in three channels, because it is the closest to human colour perception. The histogram of each channel is successively split into regions by thresholding. The best threshold to be applied is automatically obtained as a combination of three thresholding strategies: (a Otsu’s method, (b Isodata algorithm, and (c Fuzzy thresholding. The fusion of these automatic thresholding techniques and the design of the classification strategy are some of the main findings of the paper, which allows an estimation of the damages and a prediction of the oat production.

  18. Rule-based Mamdani-type fuzzy modelling of thermal performance of fintube evaporator under frost conditions

    Ozen Dilek Nur

    2016-01-01

    Full Text Available Frost formation brings about insulating effects over the surface of a heat exchanger and thereby deteriorating total heat transfer of the heat exchanger. In this study, a fin-tube evaporator is modeled by making use of Rule-based Mamdani-Type Fuzzy (RBMTF logic where total heat transfer, air inlet temperature of 2 °C to 7 °C and four different fluid speed groups (ua1=1; 1.44; 1.88 m s-1, ua2=2.32; 2.76 m s-1, ua3=3.2; 3.64 m s-1, ua4=4.08; 4.52; 4.96 m s-1 for the evaporator were taken into consideration. In the developed RBMTF system, outlet parameter UA was determined using inlet parameters Ta and ua. The RBMTF was trained and tested by using MATLAB® fuzzy logic toolbox. R2 (% for the training data and test data were found to be 99.91%. With this study, it has been shown that RBMTF model can be reliably used in determination of a total heat transfer of a fin-tube evaporator.

  19. Digital image sensor-based assessment of the status of oat (Avena sativa L.) crops after frost damage.

    Macedo-Cruz, Antonia; Pajares, Gonzalo; Santos, Matilde; Villegas-Romero, Isidro

    2011-01-01

    The aim of this paper is to classify the land covered with oat crops, and the quantification of frost damage on oats, while plants are still in the flowering stage. The images are taken by a digital colour camera CCD-based sensor. Unsupervised classification methods are applied because the plants present different spectral signatures, depending on two main factors: illumination and the affected state. The colour space used in this application is CIELab, based on the decomposition of the colour in three channels, because it is the closest to human colour perception. The histogram of each channel is successively split into regions by thresholding. The best threshold to be applied is automatically obtained as a combination of three thresholding strategies: (a) Otsu's method, (b) Isodata algorithm, and (c) Fuzzy thresholding. The fusion of these automatic thresholding techniques and the design of the classification strategy are some of the main findings of the paper, which allows an estimation of the damages and a prediction of the oat production.

  20. Identifying areas susceptible to desertification in the Brazilian Northeast

    R. M. da Silva Pinto Vieira

    2014-12-01

    Full Text Available 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.

  1. Advances in Researches on Frost-resistance Mechanisms of Plants%植物寒冻抗性分子机理研究进展

    李先文; 谢素霞; 李勋

    2011-01-01

    Frost resistance is one of the important characteristics of plants, which consists of inherence cold-tolerance in unacclimation and increased frost - tolerance during acclimation in antifrost plants.The inherence cold-tolerance derived from higher content of unsaturated fatty acid in plasmalemma.The antioxidant defense system of cell can fulfill the antioxidation needs in low-temperature, and the cytoskeleton can be regulated to adapt plants to low - temperature conditions.The increased frost - tolerance originates from many activated cold-induced genes and synthesis of a lot of cold shock protein, which enhance frost-tolerance of plants.This paper summarized the advances on plant cold -tolerance mechanisms in recent studies, in order to give theoretical direction on frost mitigation and antifrost breeding of crops.%耐冷植物的耐冷性是由未驯化时即拥有的"固有耐冷性"和"冷驯化后增加的抗冻性"两部分组成.固有耐冷性的形成主要是由于其细胞膜中含有较多的不饱和脂肪酸、细胞的抗氧化系统可满足其冷保护需求、细胞的骨架体系在低温胁迫时可进行适当的调整.而冷驯化后增加的抗冻性主要是由于启动了大量冷诱导基因的表达,合成了多种冷诱导蛋白,它们通过改善细胞的各种结构、调节细胞物质和能量代谢的平衡等过程使植物体的抗冻性得以大大提升.用50篇文献综述了植物抗冻性方面的研究成果,旨在为植物的防冻减灾以及抗冻育种提供理论指导.

  2. 一级大豆油抗冻性影响因素的研究%Influencing factors of frost resistance of first grade soybean oil

    徐爱军

    2013-01-01

    从原料大豆和加工工艺两个角度系统地分析了一级大豆油抗冻性的主要影响因素.结果表明:脂肪酸组成的分布情况对一级大豆油抗冻性影响很大,在一定程度上,饱和脂肪酸含量与凝固时间有较好的相关性;不同原料产地的大豆生产出来的大豆油因脂肪酸组成的分布不同,导致其抗冻性有一定的差异;加工工艺的影响是通过加工过程中改变脂肪酸组成的分布情况进而改变成品油的抗冻性,指标相近的大豆毛油经过不同的加工工艺精炼,得到的一级大豆油的抗冻性有时会有很大的差异.%The main influencing factors of frost resistance of first grade soybean oil were analyzed from the raw soybean and processing. The results showed that the distribution of fatty acid composition had great effect on frost resistance. To some extent, the content of saturated fatty acid and solidification time had good correlation. Due to the differences of fatty acid composition distributions of soybean oils produced by raw soybeans of different sources, the frost resistance was different. It was the change of the distribution of fatty acid composition during the refining process that affected the frost resistance of product oil. Produced by different refining processes, though indexes of the crude soybean oils were similar, the frost resistance of first grade soybean oils sometimes had great differences.

  3. Prion protein and scrapie susceptibility

    Smits, M.A.; Bossers, A.; Schreuder, B.E.C.

    1997-01-01

    This article presents briefly current views on the role of prion protein (PrP) in Transmissible Spongiform Encephalopathies or prion diseases and the effect of PrP polymoryhisms on the susceptibility to these diseases, with special emphasis on sheep scrapie. The PrP genotype of sheep apears to be a

  4. Topological susceptibility from overlap fermion

    应和平; 张剑波

    2003-01-01

    We numerically calculate the topological charge of the gauge configurations on a finite lattice by the fermionic method with overlap fermions. By using the lattice index theorem, we identify the index of the massless overlap fermion operator to the topological charge of the background gauge configuration. The resulting topological susceptibility X is in good agreement with the anticipation made by Witten and Veneziano.

  5. Topological susceptibility from the overlap

    Del Debbio, Luigi; Pica, Claudio

    2003-01-01

    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. Theref...

  6. 湖北省倒春寒发生程度评估模型%Assessment to Impacts of Late Spring Frosts in Hubei Province

    马德栗; 刘敏; 李兰; 邓爱娟

    2011-01-01

    The characteristics of late spring frost, including the temperature decreasing range, average daily minimum temperature continues days, was analyzed based on late spring frost data from 9 stations in Hubei province from 1951 to 2010. Assessment model to forecasting late spring frost was established by using principal component analysis method.The results showed that the frequency of late spring frost in March generally decreased in Hubei province last 60years.The frequency of late spring frost in April decreased obviously during the 1980s and 1990s but increased in the first 10 years of this century. From decadal aspect, there was no clear trend in the average maximums temperature decrease,but it was greater in March than that in April. The minimum daily average temperature of late spring frost in March and April decreased slightly in the first 10 years of this century. The average duration of late spring frost decreased slightly from 1951 to 2010, as totally 4. 1 days.%选取湖北省9个代表站历史倒春寒灾害序列资料,分析1951-2010年倒春寒过程中最大降温幅度、最低日平均气温、持续天数变化的特征,结合主成分分析法构建倒春寒评估模型,探讨湖北省倒春寒发生影响程度.结果表明:60a来,湖北3月倒春寒发生频次总体呈下降趋势,4月倒春寒频次以20世纪60、70年代最多,80、90年代明显下降,而2000-2010年又有所增加;倒春寒发生过程中,平均最大降温幅度的年代际间变化不大,但3月最大降温幅度大于4月;3、4月倒春寒过程最低日平均气温按年代比较显示,在2000-2010年有所降低,但不明显;1951-2010年,倒春寒持续天数平均为4.1d,呈不显著的下降趋势.运用评估模型埘2010年4月12-15日的倒春寒过程评估表明,9个代表站中5站为中度倒春寒,4站为轻度倒春寒.

  7. Soil formation.

    Breemen, van N.; Buurman, P.

    1998-01-01

    Soil Formation deals with qualitative and quantitative aspects of soil formation (or pedogenesis) and the underlying chemical, biological, and physical processes. The starting point of the text is the process - and not soil classification. Effects of weathering and new formation of minerals, mobilis

  8. A Computational Model of Water Migration Flux in Freezing Soil in a Closed System%封闭系统正冻土水流的一个计算模型

    裘春晗

    2005-01-01

    A computational model of water migration flux of fine porous soil in frost heave was investigated in a closed system. The model was established with the heat-mass conservation law and from some previous experimental results. Through defining an auxiliary function an empirical function in the water migration flux, which is difficult to get, was replaced. The data needed are about the water content along the soil column after test with enough long time. We adopt the test data of sample soil columns in [1] to verify the model. The result shows it can reflect the real situation on the whole.

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

    Koren, Victor; Smith, Michael; Cui, Zhengtao

    2014-11-01

    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.

  10. Characteristics of Frost Days and Accumulated Temperature in Eastern Gansu Over the Last 40 Years%1971年至2010年陇东地区霜冻与积温变化特征

    王媛媛; 张勃

    2012-01-01

    本文基于陇东地区15个气象站点1971年-2010年的逐日气温和地温资料,采用相关分析、气候倾向率、MK突变检验法,结合GIS空间分析技术,对各站逐年的初、终霜日、无霜期及≥0℃、≥10℃和〈0℃积温与持续日数等进行定量化分析,并阐述其时空变化特征及相互关系。结果表明:陇东地区初霜日和无霜期分别与纬度和海拔呈负相关,与经度呈正相关,终霜日则与纬度和海拔呈正相关,与经度呈负相关;20世纪70年代和80年代初霜日偏早,终霜日偏晚,无霜期较短,自90年代以来呈反向变化;大部分地区初霜日后推,终霜日提前,无霜期延长,主要集中在中南部的镇原、崇信等地;初霜日和无霜期的突变年分别在1986年、1987年和1984年,终霜日无明显突变年。本区积温呈显著上升趋势,积温年均最大值与年均最晚初霜日、最早终霜日和最长无霜期都位于陇东南部地区;积温年均最小值与年均最早初霜日、最晚终霜日和最短无霜期则分布于西部和北部地区。%Using daily air temperature and ground temperature data for 15 meteorological stations in eastern Gansu Province from 1971-2010 we conducted correlation analyses,determined the rate of climate tendency and moving t-test,and applied GIS spatial analysis techniques and mathematical statistics theory.Agro-climatic resources of the first frost date,the last frost date,the frost-free period and ≥0℃,≥10℃,and 0℃ accumulated temperature and number of days were quantitatively analyzed.Variations in temporal and spatial characteristics and the relationship between frost days and accumulated temperature were illuminated.Our goals were to fully understand and use the local agro-climatic resources,and guide the adjustment of local cropping systems,agricultural production and activities.The results showed that the first frost date and frost-free period were negatively correlated with elevation

  11. [Relationship among soil enzyme activities, vegetation state, and soil chemical properties of coal cinder yard].

    Wang, Youbao; Zhang, Li; Liu, Dengyi

    2003-01-01

    From field investigation and laboratory analysis, the relationships among soil enzyme activities, vegetation state and soil chemical properties of coal cinder yard in thermal power station were studied. The results showed that vegetation on coal cinder yard was distributed in scattered patch mainly with single species of plant, and herbs were the dominant species. At the same time, the activity of three soil enzymes had a stronger relativity to environment conditions, such as vegetation state and soil chemical properties. The sensitivity of three soil enzymes to environmental stress was in order of urease > sucrase > catalase. The relativity of three soil enzymes to environmental factor was in order of sucrase > urease > catalase. Because of urease being the most susceptible enzyme to environmental conditions, and it was marked or utmost marked interrelated with vegetation state and soil chemical properties, urease activity could be used as an indicator for the reclamation of wasteland.

  12. Soil metagenomics and tropical soil productivity

    Karen A Garrett

    2009-01-01

    This presentation summarizes research in the soil metagenomics cross cutting research activity. Soil metagenomics studies soil microbial communities as contributors to soil health.C CCRA-4 (Soil Metagenomics)

  13. Use of engineered soils beneath low-level radioactive waste disposal facilities

    Sandford, T.C.; Humphrey, D.N.; DeMascio, F.A. [Univ. of Maine, Orono, ME (United States). Dept. of Civil Engineering

    1993-03-01

    Current regulations are oriented toward locating low-level radioactive waste disposal facilities on sites that have a substantial natural soil barrier and are above the groundwater table. In some of the northern states, like Maine, the overburden soils are glacially derived and in most places provide a thin cover over bedrock with a high groundwater table. Thus, the orientation of current regulations can severely limit the availability of suitable sites. A common characteristic of many locations in glaciated regions is the rapid change of soil types that may occur and the heterogeneity within a given soil type. In addition, the bedrock may be fractured, providing avenues for water movement. A reliable characterization of these sites can be difficult, even with a detailed subsurface exploration program. Moreover, fluctuating groundwater and frost as well as the natural deposition processes have introduced macro features such as cracks, fissures, sand and silt seams, and root holes. The significant effect that these macro features have on the permeability and adsorptive capacity of a large mass is often ignored or poorly accounted for in the analyses. This paper will examine an alternate approach, which is to use engineered soils as a substitute for some or all of the natural soil and to treat the fractures in the underlying bedrock. The site selection would no longer be primarily determined by the natural soil and rock and could even be placed in locations with no existing soils. Engineered soils can be used for below- or aboveground facilities.

  14. Soils - Volusia County Soils (Polygons)

    NSGIC GIS Inventory (aka Ramona) — Soils: 1:24000 SSURGO Map. Polygon boundaries of Soils in Volusia County, downloaded from SJRWMD and created by NRCS and SJRWMD. This data set is a digital version...

  15. Epidemic extinction in a generalized susceptible-infected-susceptible model

    Chen, Hanshuang; Huang, Feng; Zhang, Haifeng; Li, Guofeng

    2017-01-01

    We study the extinction of epidemics in a generalized susceptible-infected-susceptible model, where a susceptible individual becomes infected at the rate λ when contacting m infective individual(s) simultaneously, and an infected individual spontaneously recovers at the rate μ. By employing the Wentzel-Kramers-Brillouin approximation for the master equation, the problem is reduced to finding the zero-energy trajectories in an effective Hamiltonian system, and the mean extinction time depends exponentially on the associated action S and the size of the population N, ˜ \\exp ≤ft(NS\\right) . Because of qualitatively different bifurcation features for m  =  1 and m≥slant 2 , we derive independently the expressions of S as a function of the rescaled infection rate λ /μ . For the weak infection, S scales to the distance to the bifurcation with an exponent 2 for m  =  1 and 3/2 for m≥slant 2 . Finally, a rare-event simulation method is used to validate the theory.

  16. Susceptibility of several floriculture crops to three common species of meloidogyne in Florida

    The current and pending restriction on the use of soil fumigants and other nematicides effective in controlling nematodes in field grown floriculture crops has increased the importance of determining the relative susceptibility of these crops to important species of root-knot nematodes. Greenhouse ...

  17. Environmental factors influencing soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient in subarctic tundra (Abisko, Sweden).

    Tsyganov, Andrey N; Milbau, Ann; Beyens, Louis

    2013-05-01

    Shifts in community composition of soil protozoa in response to climate change may substantially influence microbial activity and thereby decomposition processes. However, effects of climate and vegetation on soil protozoa remain poorly understood. We studied the distribution of soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient (from below the treeline at 500 m to the mid-alpine region at 900 m a.s.l.) in subarctic tundra. To explain patterns in abundance, species diversity and assemblage composition of testate amoebae, a data set of microclimate and soil chemical characteristics was collected. Both elevation and vegetation influenced the assemblage composition of testate amoebae. The variation was regulated by interactive effects of summer soil moisture, winter soil temperature, soil pH and nitrate ion concentrations. Besides, soil moisture regulated non-linear patterns in species richness across the gradient. This is the first study showing the effects of winter soil temperatures on species composition of soil protozoa. The effects could be explained by specific adaptations of testate amoebae such as frost-resistant cysts allowing them to survive low winter temperatures. We conclude that the microclimate and soil chemical characteristics are the main drivers of changes in protozoan assemblage composition in response to elevation and vegetation.

  18. Soil infiltrometer

    Mehler, M.R.

    1990-09-18

    This patent describes an infiltrometer useful for field testing soil permeability. It comprises: a large reservoir having an open bottom resting on the soil; a small reservoir having an open bottom resting on the soil, the small reservoir being positioned within the large reservoir; the small reservoir comprising a relatively large receptacle adjacent the soil and a relatively small receptacle connected thereto and extending upwardly therefrom; the volume of the large reservoir greatly exceeding the volume of the small reservoir; the ratio of the upper surface area of liquid in the large reservoir to the surface area of the soil covered thereby greatly exceeding the ratio of the upper surface area of liquid in the relatively small receptacle of the small reservoir to the surface area of the soil covered thereby; and means for determining the amount of liquid from the small reservoir permeating into the soil.

  19. Recent divergences in stratospheric water vapor measurements by frost point hygrometers and the Aura Microwave Limb Sounder

    Hurst, Dale F.; Read, William G.; Vömel, Holger; Selkirk, Henry B.; Rosenlof, Karen H.; Davis, Sean M.; Hall, Emrys G.; Jordan, Allen F.; Oltmans, Samuel J.

    2016-09-01

    Balloon-borne frost point hygrometers (FPs) and the Aura Microwave Limb Sounder (MLS) provide high-quality vertical profile measurements of water vapor in the upper troposphere and lower stratosphere (UTLS). A previous comparison of stratospheric water vapor measurements by FPs and MLS over three sites - Boulder, Colorado (40.0° N); Hilo, Hawaii (19.7° N); and Lauder, New Zealand (45.0° S) - from August 2004 through December 2012 not only demonstrated agreement better than 1 % between 68 and 26 hPa but also exposed statistically significant biases of 2 to 10 % at 83 and 100 hPa (Hurst et al., 2014). A simple linear regression analysis of the FP-MLS differences revealed no significant long-term drifts between the two instruments. Here we extend the drift comparison to mid-2015 and add two FP sites - Lindenberg, Germany (52.2° N), and San José, Costa Rica (10.0° N) - that employ FPs of different manufacture and calibration for their water vapor soundings. The extended comparison period reveals that stratospheric FP and MLS measurements over four of the five sites have diverged at rates of 0.03 to 0.07 ppmv year-1 (0.6 to 1.5 % year-1) from ˜ 2010 to mid-2015. These rates are similar in magnitude to the 30-year (1980-2010) average growth rate of stratospheric water vapor ( ˜ 1 % year-1) measured by FPs over Boulder (Hurst et al., 2011). By mid-2015, the FP-MLS differences at some sites were large enough to exceed the combined accuracy estimates of the FP and MLS measurements.

  20. Biofilm susceptibility to metal toxicity.

    Harrison, Joe J; Ceri, Howard; Stremick, Carol A; Turner, Raymond J

    2004-12-01

    This study compared bacterial biofilm and planktonic cell susceptibility to metal toxicity by evaluating the minimum inhibitory concentration (MIC), the planktonic minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) using the MBEC device. In total, 17 metal cations and oxyanions, chosen to represent groups VIB to VIA of the periodic table, were each tested on biofilm and planktonic cultures of Escherichia coli JM109, Staphylococcus aureus ATCC 29213, and Pseudomonas aeruginosa ATCC 27853. In contrast to control antibiotic assays, where biofilm cultures were 2 to 64 times less susceptible to killing than logarithmically growing planktonic bacteria, metal compounds killed planktonic and biofilm cultures at the same concentration in the vast majority of combinations. Our data indicate that, under the conditions reported, growth in a biofilm does not provide resistance to bacteria against killing by metal cations or oxyanions.

  1. Topological susceptibility from the overlap

    Del Debbio, L; Debbio, Luigi Del; Pica, Claudio

    2004-01-01

    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 ...

  2. Antimycotics susceptibility testing of dermatophytes

    Arsić-Arsenijević Valentina

    2010-01-01

    Full Text Available Dermatophytes are moulds that produce infections of the skin, hair and nails of humans and animals. The most common forms among these infections are onychomycosis and tinea pedis affecting 20% of world population. These infections are usually chronic. The treatment of dermatophytoses tends to be prolonged partly because available treatments are not very effective. Antifungal drug consumption and public health expenditure are high worldwide, as well as in Serbia. For adequate therapy, it is necessary to prove infection by isolation of dermatophytes and to test the antifungal susceptibility of isolates. Susceptibility testing is important for the resistance monitoring, epidemiological research and to compare in vitro activities of new antifungal agents. The diffusion and dilution methods of susceptibility tests are used, and technical issues of importance for the proper performance and interpretation of test results are published in the document E.DEF 9.1 (EUCAST and M38-A2 (CLSI. The aim of our paper is to promptly inform the public about technical achievements in this area, as well as the new organization of laboratory for medical mycology in our country. The formation of laboratory networks coordinated by the National Reference Laboratory for the cause of mycosis need to enable interlaboratory studies and further standardization of methods for antifungal susceptibility testing of dermatophytes, reproducibility of tests and clinical correlation monitoring (MIK values and clinical outcome of dermatophytosis. The importance of the new organization is expected efficient improvement in the dermatophytosis therapy at home, better quality of patient's life and the reduction of the cost of treatment.

  3. A New Approach for Calculating Vacuum Susceptibility

    宗红石; 平加伦; 顾建中

    2004-01-01

    Based on the Dyson-Schwinger approach, we propose a new method for calculating vacuum susceptibilities. As an example, the vector vacuum susceptibility is calculated. A comparison with the results of the previous approaches is presented.

  4. Runoff and interrill erosion in sodic soils treated with dry PAM and phosphogypsum

    Seal formation at the soil surface during rainstorms reduces rain infiltration and leads to runoff and erosion. An increase in soil sodicity increases soil susceptibility to crusting, runoff, and erosion. Surface application of dissolved polyacrylamide (PAM) mixed with gypsum was found to be very ef...

  5. Susceptibility of Shallow Landslide in Fraser Hill Catchment, Pahang Malaysia

    Wan Nor Azmin Sulaiman

    2010-01-01

    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

  6. Research Progress in Anti-frosting Performance of Super-hydrophobic Surfaces%超疏水表面抑制结霜研究进展

    陈小娇; 武卫东; 汪德龙

    2015-01-01

    Super-hydrophobic surfaces are widely used in manufacturing, owning to its high apparent contact angle and low sliding angle. This article summarized the latest international and domestic research progresses in the anti-frosting performance of super-hydrophobic surfaces and introduced the process characteristics of condensation, icing and frost depositing processes as well as the influence of super-hydrophobicity on the frosting process. A large body of evidence indicated that the time needed for con-densing and frosting was extended with thinner frost layer, fluffier and weaker structure, which could be easily removed by external force. However, some super-hydrophobic surfaces suffered from loss of super-hydrophobicity during condensing, which limited the potential of super-hydrophobic surfaces as anti-frosting materials. Super-hydrophobic surfaces with nano-structures solve the afore-mentioned weakness, some of them show excellent performances owning to jumping of condensate on those surfaces. Finally, the future development of super-hydrophobic surfaces was prospected.%超疏水表面以其超高的表观接触角和很小的滚动角在工业中获得广泛的应用。综述了近期国内外超疏水表面在抑霜方面的研究新进展,归纳了超疏水表面的冷凝、结冰和落霜过程的过程特点和疏水性对结霜过程的影响。超疏水表面能显著延迟冷凝发生和开始结霜的时间,降低霜层的厚度。与普通表面相比,超疏水表面的霜层结构更为蓬松脆弱,可在外力作用下轻松去除,表现出较好的抑霜性能。由于部分超疏水表面在冷凝阶段丧失疏水性从而丧失抑霜性能,大大地限制了超疏水表面在抑制结霜方面的潜力。纳米结构超疏水表面较好地解决了上述问题,一部分纳米表面由于冷凝液滴的弹跳现象而表现出极佳的抑霜性能。最后,对超疏水表面研究的发展进行了展望。

  7. Anti-frost structure for the cryogenic shield of spacecraft%空间飞行器冷屏防霜结构

    陈叔平; 谭风光; 吴睿; 吴北民; 谢福寿; 温永刚; 陈光奇

    2012-01-01

    空间飞行器冷屏是一种包裹在高速飞行器外的基于相变制冷的装置,可以降低高速飞行器在太空飞行时的红外辐射特性.冷屏在发射前需要进行低温制冷剂加注.如果没有保护装置,在地面加注时会引起冷屏表面严重结霜,恶化冷屏表面红外辐射特性.设计了一种由保温层和氮气保护层组成的防霜结构.氮气保护层利用氮气在低温下不易凝结的特性,保护冷屏外壳使不结霜;保温层利用保温材料的热阻特性,使保温层外壁温度在当地露点温度以上,从而防止空气中水蒸气在保温层外壁凝结.建立了氮气保护气填充速度随时间变化的关系式.实验表明,冷屏表面和保温层外壳均实现了零结霜,取得了很好的防霜效果.%The cryogenic shield of spacecraft is a device used to wrap the high-speed spacecraft up based on phase-change refrigeration. It can reduce the infrared radiation of the spacecraft flying in space. Before launching, the cryogenic shield needs to be filled up with low-temperature refrigerant. Without a frost prevention device, the filling process of liquid low-temperature refrigerant on the ground would cause severe frosting on the surface of the cryogenic shield so as to weaken its resistance to infrared radiation. An anti-frost structure was devised, which were made up by nitrogen protection layer and thermal insulation. For nitrogen does not easily congeal at low-temperature, it can protect the cryogenic shield from frosting. And the thermal insulation made of insulation materials has large thermal resistance, so it can make sure that the outside temperature of thermal insulation is above the local dew point and the vapor in the atmospheric environment will not congeal on the outside surface of the thermal insulation. Meanwhile the function relation of filling speed of protection gas with time was deduced. The experiment shows that there is no frost on the surface of the cryogenic

  8. Scenarios Susceptible to Induced Liquefaction Caused by High Magnitude Earthquakes in Santiago de Cuba

    Liuska Fernández-Diéguez

    2016-05-01

    Full Text Available The objective of this investigation was to define the zoning of soil liquefaction potential for the Guillermón Moncada Popular Council in the municipality of Santiago de Cuba. The engineering and geological conditions and seismic peculiarities favoring a seism to take place were assessed. The safety factor was re-calculated after determining possible maximum intensity values based on seismic magnitudes that can trigger the soil of the investigated area to liquefy. A scheme of the area´s soil susceptibility to liquefaction was obtained. Based on this result, it was concluded that the sectors that are most likely to experience soil liquefaction if an earthquake of magnitudes ranging between 7,75 and 8 occurs are located towards the center-east of the Popular Council with sandy-clayey soils being predominant. This information is very useful for the location and planning of engineering construction works in the area.

  9. Contribution to the edaphic components definition in the desertification susceptibility index

    Sampaio, E. P.; Corte-Real, J. A.

    2009-07-01

    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.

  10. Soil friability

    Munkholm, Lars Juhl

    2011-01-01

    This review gathers and synthesizes literature on soil friability produced during the last three decades. Soil friability is of vital importance for crop production and the impact of crop production on the environment. A friable soil is characterized by an ease of fragmentation of undesirably large...... aggregates/clods and a difficulty in fragmentation of minor aggregates into undesirable small elements. Soil friability has been assessed using qualitative field methods as well as quantitative field and laboratory methods at different scales of observation. The qualitative field methods are broadly used...... by scientists, advisors and farmers, whereas the quantitative laboratory methods demand specialized skills and more or less sophisticated equipment. Most methods address only one aspect of soil friability, i.e. either the strength of unconfined soil or the fragment size distribution after applying a stress. All...

  11. 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

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

    2008-04-15

    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)

  12. Experimental Study on the Frost Resistance of Recycled Coarse Aggregate Concrete%再生粗骨料混凝土抗冻性试验研究

    冯嘉; 李秋义; 宋菁; 张健

    2011-01-01

    再生混凝土的研究与应用对于保护环境具有重大意义,其耐久性则是影响生产应用的重要指标.重点研究了再生粗骨料取代量、矿物掺和料等因素对再生混凝土抗冻性的影响.结果表明:再生粗骨料混凝土的质量损失率均满足5%的试验要求,且质量损失率随着再生骨料取代率的增加而下降;再生粗骨料混凝土的相对动弹模量低于天然骨料混凝土,达到了冻融循环抵抗性指标,满足抗冻性要求;掺普通矿粉的再生混凝土比掺粉煤灰的再生混凝土抗冻性好;硅灰对提高再生混凝土(掺粉煤灰)的抗冻性有明显作用.%The research and application of recycled concrete are of great significance for environmental protection and its durability is an important index of production and application.The influences of the replacement rate of recycled coarse aggregate,mineral admixture and other factors on the frost resistance of recycled concrete are studied in this paper.The experimental results show that the mass loss rate of recycled coarse aggregate concrete meets the experimental requirement by 5% and it descends along with the increase of the replacement rate of the recycled fine aggregate.The relative dynamic modulus of recycled coarse aggregate concrete is inferior to that of the natural aggregate concrete,but it reaches the freeze-thawing circulation norm and meets frost resistance requirements.The frost resistance of the recycled aggregate concrete with mineral powder is better than that of the recycled aggregate concrete with fly ash.The silicon ash can enhance the frost resistance of the recycled concrete(with fly ash) significantly.

  13. (Contaminated soil)

    Siegrist, R.L.

    1991-01-08

    The traveler attended the Third International Conference on Contaminated Soil, held in Karlsruhe, Germany. The Conference was a status conference for worldwide research and practice in contaminated soil assessment and environmental restoration, with more than 1500 attendees representing over 26 countries. The traveler made an oral presentation and presented a poster. At the Federal Institute for Water, Soil and Air Hygiene, the traveler met with Dr. Z. Filip, Director and Professor, and Dr. R. Smed-Hildmann, Research Scientist. Detailed discussions were held regarding the results and conclusions of a collaborative experiment concerning humic substance formation in waste-amended soils.

  14. Landslide susceptibility analysis using an artificial neural network model

    Mansor, Shattri; Pradhan, Biswajeet; Daud, Mohamed; Jamaludin, Normalina; Khuzaimah, Zailani

    2007-10-01

    This paper deals with landslide susceptibility analysis using an artificial neural network model for Cameron Highland, Malaysia. Landslide locations were identified in the study area from interpretation of aerial photographs and field surveys. Topographical/geological data and satellite images were collected and processed using GIS and image processing tools. There are ten landslide inducing parameters which are considered for the landslide hazards. These parameters are topographic slope, aspect, curvature and distance from drainage, all derived from the topographic database; geology and distance from lineament, derived from the geologic database; landuse from Landsat satellite images; soil from the soil database; precipitation amount, derived from the rainfall database; and the vegetation index value from SPOT satellite images. Landslide hazard was analyzed using landslide occurrence factors employing the logistic regression model. The results of the analysis were verified using the landslide location data and compared with logistic regression model. The accuracy of hazard map observed was 85.73%. The qualitative landslide susceptibility analysis was carried out using an artificial neural network model by doing map overlay analysis in GIS environment. This information could be used to estimate the risk to population, property and existing infrastructure like transportation network.

  15. Mechanisms of inherited cancer susceptibility

    Shirley HODGSON

    2008-01-01

    A small proportion of many cancers are due to inherited mutations in genes, which result in a high risk to the individual of developing specific cancers. There are several classes of genes that may be involved: tumour suppressor genes, oncogenes, genes encoding proteins involved in DNA repair and cell cycle control, and genes involved in stimulating the angiogenic pathway. Alterations in susceptibility to cancer may also be due to variations in genes involved in carcinogen metabolism. This review discusses examples of some of these genes and the associated clinical conditions caused by the inheritance of mutations in such genes.

  16. Polygenic susceptibility to testicular cancer

    Litchfield, Kevin; Mitchell, Jonathan S; Shipley, Janet

    2015-01-01

    BACKGROUND: The increasing incidence of testicular germ cell tumour (TGCT) combined with its strong heritable basis suggests that stratified screening for the early detection of TGCT may be clinically useful. We modelled the efficiency of such a personalised screening approach, based on genetic...... known TGCT susceptibility variants. The diagnostic performance of testicular biopsy and non-invasive semen analysis was also assessed, within a simulated combined screening programme. RESULTS: The area under the curve for the TGCT PRS model was 0.72 with individuals in the top 1% of the PRS having...

  17. Antimicrobial susceptibility of equine and environmental isolates of Clostridium difficile.

    Båverud, V; Gunnarsson, A; Karlsson, M; Franklin, A

    2004-01-01

    The antimicrobial susceptibility of 50 Clostridium difficile isolates, 36 of them from horse feces and 14 from environmental sites, was determined by broth microdilution. The antimicrobial agents tested were avilamycin, cephalothin, chloramphenicol, clindamycin, erythromycin, gentamicin, neomycin, oxacillin, oxytetracycline, penicillin, spiramycin, streptomycin, trimethoprim/sulfamethoxazole, vancomycin, and virginiamycin. All isolates were susceptible to vancomycin (MIC MICs of erythromycin, oxytetracycline, spiramycin, and virginiamycin showed a bimodal distribution. Compared with the majority of isolates, the MICs of erythromycin (MIC > 16 microg/ml), oxytetracycline (MIC >/=32 microg/ml), spiramycin (MIC > 16 microg/ml), and virginiamycin (MIC 8-16 microg/ml) were higher for 18 isolates. Those were mainly isolated from horses at animal hospitals and further from environmental sites at a stud farm. In contrast, all isolates, except one, from healthy foals had low MICs of erythromycin, spiramycin, virginiamycin, and oxytetracycline. The isolates from soil in public parks had also low MICs of these antimicrobial agents. Broth microdilution appeared both reliable and reproducible for susceptibility testing of C. difficile. The method was also readily performed and the MIC endpoints were easily read.

  18. Structural analysis and design of frost resistance function for subgrade of high-speed railway ballasted track in cold regions

    Qiang Luo; WenQiang Lv; QingZhi Ye; RuiGuo Zhang

    2015-01-01

    According to the technical characteristics of short fixed wheelbase of a high-speed carriage, a subgrade-track integrated space mechanical response analysis model is proposed for trains under the action of biaxial load after the comparison of the stress distribution characteristics of the ballast track subgrade bed structures for high-speed railway under the action of uniaxial load and biaxial load. The loading threshold value (high-cycle long-term dynamic strength) under the circum-stance where the cumulative deformation of subgrade structure gradually develops and finally reaches the convergent state, and its relationship with the foundation coefficient K30 were deduced, based on the characteristics of cumulative defor-mation evolution obtained from the unit structure filling model test under the action of cyclic loading. In view of structure stability and frost resistance requirements of the railway subgrade in cold regions, technical conditions to maintain good service performance of subgrade structure of high-speed railway ballasted track are discussed and analyzed. Study results show that the additive effect manifests itself obviously for railway train bogies under the action of biaxial load than uni-axial load, which has a significant dynamic effect on the subgrade bed bottom and a slight effect on the surface layer. Thus, the adoption of a biaxial load model in the design of a high-speed railway subgrade accurately reflects the vehicle load. Pursuant to the structure design principle, the design method of the subgrade structure of high-speed railway ballasted track is proposed to meet the technical requirements such as structural strength, bearing stiffness and high-cyclic and long-term stability. Technical indicators are obtained for the variation of thickness of the surface layer of reinforced sub-grade bed in the double-layer subgrade mode along with the change of K30 at the subgrade bed bottom. The double-layer structure mode of"closure on the upper

  19. Effects of density distribution of scattering media on radiation transfer. Case of growing frost layer; Fukusha denpa ni ataeru sanransei baitai no mitsudo bunpu no eikyo. Seicho kateini aru shimoso no baai

    Yoshida, A.; Washio, S. [Okayama University, Okayama (Japan); Haida, T. [NGK Insulators, Ltd., Nagoya (Japan); Matsumoto, E. [Oji Paper Co. Ltd., Tokyo (Japan)

    1999-09-25

    The main interest was taken in the effects of the density distribution on the radiation transfer in the scattering media. The frost layer in the early growth stage under the control of diffusion was chosen as the media. Numerical analysis of the radiation transfer was carried out by using a modified Monte Carlo method on the basis of the geometrical optics. A diffusion limited aggregation theory was introduced to simulate the growth of frost layer with treelike structure. The relation between the density distribution and the transmittance of the simulated model was made clear by the numerical analysis. On the basis of its result, the optical measurements in the visible wavelength region were utilized to evaluate the density distribution in the frost layer, which varied with the cooling condition, from the transmittance values. (author)

  20. Soil Solution

    Sonneveld, C.; Voogt, W.

    2009-01-01

    The characteristics of the soil solution in the root environment in the greenhouse industry differ much from those for field grown crops. This is caused firstly by the growing conditions in the greenhouse, which strongly differ from those in the field and secondly the function attributed to the soil

  1. Linking soil biodiversity and agricultural soil management

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

    2012-01-01

    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 o

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

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

    2007-01-01

    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

  3. 浅析罗伯特·弗罗斯特诗歌中的平衡性%The balance in Robert frost's poetry

    朱先萍

    2015-01-01

    罗伯特·弗罗斯特(Robert Frost,1874--1963)是20世纪美国最著名的诗人之一。他通过诗歌把乡村和城市、地方和世界、人与自然等因素并列、对比与揉合起来,诗境隽永优美,富含深刻的人生哲理。诗人的一生都在“无序中创造有序”,在矛盾中寻找平衡。他总是能在纷杂与矛盾的万物中找到平衡点,追寻人与自然,人与人,人与社会的和谐。%Robert Frost (1874-1963, Robert Frost) is one of America's most famous poets in the 20th century. His poems through the country and city, local and world, man and nature factors such as joint, contrast and close up, a beautiful poem meaningful, is rich in profound life philosophy. In the life of the poet "disorderly create orderly", balance in the conflict. He always can find balance in mixed and contradictory things, pursue the human and the nature, human and the harmony of man and society.

  4. Occurrence and Defense of Frost Disaster in Anhui Province%安徽省霜冻灾害的发生及防御

    张彩丽

    2015-01-01

    The cause,types,spatial and temporal distribution regularities of frost disaster in Anhui Province were intro-duced at first,then the harm mechanism and the harm to crops were put forward, at last,the defense measures were mainly proposed,such as smoking method,irri-gation method and covering method.This study provided a basis for mitigating frost disaster risks and reducing the agricul-tural production losses.%介绍了安徽省霜冻灾害的成因、类型、时空分布规律,并提出其危害机理、对农作物的危害等,重点提出防御措施,如烟熏法、灌水法、覆盖法,为减轻霜冻危害风险,减少农业生产损失提供了依据。

  5. Metaphor and Symbolism: Two Typical Features of Frost's Poetry"%隐喻和象征:弗罗斯特诗歌的两大特色

    陈燕; 李思红

    2008-01-01

    With its seemingly simplicity and ambiguity in language but rich implications in thinking, Frost's poetry often produces arewarding and lasting impression on the readers. The authors hold that the main characteristics of his poetry are metaphor and symbolism,and his famous typical poems reveal profound philosophical ideas that are Frost' s interpretation of life and existence as well as the relation-ship between man and nature.%弗罗斯特诗歌的语言似乎简单、含糊,但其思想蕴意深刻,常常给读者留下难忘的印象,余味无穷.本文认为弗氏的诗歌的主要特征是隐喻和象征,其著名的抒情诗中蕴涵着丰富的哲理,揭示了弗氏对人生和存在的解读和人与自然的关系.

  6. 罗伯特·弗罗斯特诗歌的文本诠释%Textual Analysis of Robert Frost's Poems

    范翠华

    2016-01-01

    Frost is a famous American poet in the 20th century .His poems are just the typical inherit-ance from the 19th American Romanticism ,especially from the transcendentalism .Through close reading , which is the core of New Criticism ,readers can hold the best sense of literary power in Frost's poems ,be-cause there are so many dense images as well as deep metaphors in his poems .The present writer analyzes the above two factors by the use of close reading and interprets different themes in his several poems ,and points out close reading is an important way to understand a poem well .%弗罗斯特是美国 20 世纪著名的诗人,他的诗歌继承了美国 19 世纪诗歌的浪漫主义传统,深受超验主义的影响.在弗罗斯特的诗歌中,通过新批评的文本细读,可以感受文学力量的强烈释放,一是作者诗歌结构中形成了密集的文学意象 ; 二是作者诗歌的意象具有非常深刻的文学隐喻.

  7. 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

    Dalen, Lars Sandved

    1998-09-01

    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.

  8. Skipping breakfast leads to weight loss but also elevated cholesterol compared with consuming daily breakfasts of oat porridge or frosted cornflakes in overweight individuals: a randomised controlled trial.

    Geliebter, Allan; Astbury, Nerys M; Aviram-Friedman, Roni; Yahav, Eric; Hashim, Sami

    2014-01-01

    Eating breakfast may reduce appetite, body weight and CVD risk factors, but the breakfast type that produces the greatest health benefits remains unclear. We compared the effects of consuming a high-fibre breakfast, a non-fibre breakfast, or no-breakfast control on body weight, CVD risk factors and appetite. A total of thirty-six overweight participants (eighteen men and eighteen women) (mean age 33·9 (sd 7·5) years, mean BMI 32·8 (sd 4·7) kg/m(2)) were randomly assigned to consume oat porridge (n = 12), frosted cornflakes (n = 12) or a water control (n = 12) breakfast daily for 4 weeks. Appetite ratings were collected on the first day and weekly thereafter. Before and after the intervention, body weight, composition, blood pressure and resting energy expenditure (REE) were measured and a fasting blood sample was collected. Across the 4 weeks, fullness was higher and hunger was lower in the oat porridge group compared with the control group (P skipping breakfast led to weight loss, it also resulted in increased total cholesterol concentrations compared with eating either oat porridge or frosted cornflakes for breakfast.

  9. Temperature variation of underlying surface of tea plantation under late frost%晚霜茶园下垫面气温变化动态

    胡永光; 茆康前; 朱霄岚

    2013-01-01

    早春晚霜冻害对早熟名优茶生产造成严重危害,为探索茶园防霜方法与技术,研究了晚霜时茶园下垫面气温的变化特点。在分析茶园小气候和晚霜形成的基础上,试验测定茶树冠层上方12 m高度范围内的气温,分析其时空分布特征,以及不同天气条件对成霜的影响。结果表明:在早春晴朗、风速小于0.5 m·s-1的夜晚,当气温降至0℃时,易随辐射逆温的出现而成霜,风速大于2.0 m·s-1或阴雨天时则无霜;逆温约始于傍晚17:30,之后逆温强度迅速增大,最大的逆温差为9.9℃;从20:00至第2日06:00逆温强度波动较平稳,平均波动率为14.1%,其后逆温强度迅速减弱,在8:00左右逆温基本消失;在1:00~6:00时段,近地气温在高度方向上分层显著,(0~3.0),(6.0~7.5) m高度范围的温升变化率较大,分别为1.51℃· m-1和1.58℃· m-1,而(3.0~6.0),(7.5~12.0) m高度范围的温升变化不明显,故6.0~7.5 m可作为防霜风机优选的安装高度。%During early spring , early-maturing superior tea tends to suffer severe late frost damage .Temperature vari-ation of underlying surface of tea plantation was studied under late frost in order to develop frost protection methods and technologies .On the basis of analysis on the microclimate of tea fields and late frost occurrence , experiments were conducted to measure the air temperature within 12 m high above the tea canopy .The spatial-temporal distribu-tion of air temperature and the influence of different weather conditions on frost occurrence were analyzed .The results showed that the radiation frost was prone to occur with thermal inversion during clear spring night when air tempera -ture was around 0℃and wind speed was less than 0.5 m· s-1 .But there was no frost during rainy or cloudy nights or when the wind speed was above 2.0 m· s-1 .Thermal inversion appeared around 17

  10. The Spatio-Temporal Characteristics of Dynamic Change of Frost-Free Period in Shandong Province Based on GIS%基于GIS的山东省无霜期时空动态变化特征

    王建源; 赵红; 胡桂芳

    2011-01-01

    为了全面分析山东省49年来霜冻的变化趋势,为区域作物结构调整及选取合适生育期的品种提供参考,应用山东省86个气象观测站1961-2009年的气象资料和山东省1∶25万数字高程,采用回归分析法对山东省的初、终霜日及无霜期进行计算,用GIS工具对其进行栅格化,得到15幅栅格面层,并分别对各栅格层进行空间分析和统计计算,并用Mann-Kendall对结果进行检验.结果表明:(1)在空间上,山东省的各个年代终霜日首先从鲁西南开始,由西南逐步向东北方向展开,最迟的是鲁中山区和山东半岛,但各地的终霜日时间在不同年代有一定的变化;初霜日首先从鲁中山区开始,由鲁西北逐步向鲁东南开展,初霜日最晚的是鲁南南部和鲁东南沿海;各个年代平均无霜期天数由北向南增加.(2)在时间上,20世纪70年代终霜日最迟,2001-2009年最早;初霜日是60、70年代最早,2001-2009年最迟;无霜期天数最少的是60、70年代,2001-2009年最多.1961-2009年山东省的终霜日变化倾向率为-2.6天/10年,统计量U为-4.00,通过显著性水平α=0.01的检验,有明显提前的趋势;初霜日变化倾向率为2.0天/10年,统计量U为3.45,有明显后推的趋势;无霜期变化倾向率为4.6 天/10年,统计量U为4.93,有明显增多的趋势.%For comprehensive analysis of trends in frost 49 years and providing reference for regional crop structure adjustment and selecting appropriate species for varieties growing period, based on the meteorological data from 1961 to 2009 of 86 meteorological stations and digital elevation models (1∶250 thousand) in Shandong province, the method of regression analysis was adopted in calculating the first/last frost dates and frost-free period.Statistical analysis and spatial analysis were carried out 15 grid layers with the first/last frost dates and frost-free period by GIS, and the results were tested by Mann-Kendall.The results showed

  11. BILATERAL KEY COMPARISON SIM.T-K6.1 ON HUMIDITY STANDARDS IN THE DEW/FROST-POINT TEMPERATURE RANGE FROM −25 °C TO +20 °C

    Meyer, C.W.; Hill, K.D.

    2015-01-01

    A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the National Research Council (NRC, Canada) between December 2014 and April, 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and NRC and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and NRC. PMID:26663952

  12. Assessment of Soil Liquefaction Potential Based on Numerical Method

    Choobasti, A. Janalizadeh; Vahdatirad, Mohammad Javad; Torabi, M.

    2012-01-01

    simplified method have been developed over the years. Although simplified methods are available in calculating the liquefaction potential of a soil deposit and shear stresses induced at any point in the ground due to earthquake loading, these methods cannot be applied to all earthquakes with the same...... accuracy, also they lack the potential to predict the pore pressure developed in the soil. Therefore, it is necessary to carry out a ground response analysis to obtain pore pressures and shear stresses in the soil due to earthquake loading. Using soil historical, geological and compositional criteria......, a zone of the corridor of Tabriz urban railway line 2 susceptible to liquefaction was recognized. Then, using numerical analysis and cyclic stress method using QUAKE/W finite element code, soil liquefaction potential in susceptible zone was evaluated based on design earthquake....

  13. The effect of land use on spatial variability of soil water repelency

    Hrabovský, Andrej; Dlapa, Pavel; Chrenková, Katarína; Šimkovic, Ivan

    2016-04-01

    Soil water repellency was identified as a fundamental phenomenon during a soil survey dedicated to soil hydrological properties and processes in watersheds of the Little Carpathians Mts. (SW Slovakia). The investigated area represents the viticulture region with various soil management practices. Thus, soils of the region are influenced by deep ploughing during vineyard establishment, by cultivation of vineyards, by reforestation of abandoned vineyards as well as by long-term forestry practices. The soils developed from granitic rocks are naturally susceptible to water repellency development. The obtained results showed marked variability in physical and chemical soil properties. In particular, the soil pH values, the clay and organic carbon contents differed significantly depending on soil management. Due to these differences, the soil water repellency increased from wettable to extremely water repellent approximately in order: deeply ploughed vineyard soils water repellency on infiltration process was observed by means of field experiments.

  14. Geotechnical properties of Egyptian collapsible soils

    Khaled E. Gaaver

    2012-09-01

    Full Text Available The risk of constructing structures on collapsible soils presents significant challenges to geotechnical engineers due to sudden reduction in volume upon wetting. Identifying collapsible soils when encountered in the field and taking the needed precautions should substantially reduce the risk of such problems usually reported in buildings and highways. Collapsible soils are those unsaturated soils that can withstand relatively high pressure without showing significant change in volume, however upon wetting; they are susceptible to a large and sudden reduction in volume. Collapsible soils cover significant areas around the world. In Egypt, collapsible soils were observed within the northern portion of the western desert including Borg El-Arab region, and around the city of Cairo in Six-of-October plateau, and Tenth-of-Ramadan city. Settlements associated with development on untreated collapsible soils usually lead to expensive repairs. One method for treating collapsible soils is to densify their structure by compaction. The ongoing study presents the effect of compaction on the geotechnical properties of the collapsible soils. Undisturbed block samples were recovered from test pits at four sites in Borg El-Arab district, located at about 20 km west of the city of Alexandria, Egypt. The samples were tested in both unsoaked and soaked conditions. Influence of water inundation on the geotechnical properties of collapsible soils was demonstrated. A comparative study between natural undisturbed and compacted samples of collapsible soils was performed. An attempt was made to relate the collapse potential to the initial moisture content. An empirical correlation between California Bearing Ratio of the compacted collapsible soils and liquid limit was adopted. The presented simple relationships should enable the geotechnical engineers to estimate the complex parameters of collapsible soils using simple laboratory tests with a reasonable accuracy.

  15. 茶叶霜冻气象指数保险设计%Design of Weather Index Insurance Contact for Tea Frost

    娄伟平; 吉宗伟; 邱新法; 吴利红; 何孝笑

    2011-01-01

    根据茶叶基地历年茶叶逐日经济产出,确定茶叶进入开采期或开采期前遭受霜冻的经济损失率与最低气温的关系。利用支持向量机将位于各乡镇、街道的中尺度自动气象站的最低气温资料延长到30 a;最低气温和茶叶经济损失率相对应,因此通过根据最低气温资料计算不同等级霜冻出现风险确定茶叶经济损失风险,解决了茶叶品种种植时间短、中尺度自动气象站资料积累时间短,不能满足风险分析要求的问题。利用多种风险分析模型拟合分析各乡镇、街道茶叶处于不同开采期时的最低气温分布,从中选择最优的理论概率分布函数进行序列的风险概率估算,得到较为稳定并符合实际的风险评估结果。在风险定量分析基础上,从浙江省政策性农业保险经营的实际需要出发,综合区域产量保险和气象指数保险的优点,设计了精细化到乡镇一级的茶叶霜冻气象指数保险,降低了农业保险中存在的基差风险、逆选择和道德风险,在灾后理赔时不需要大量的人力、物力勘查定损,理赔时效高、理赔成本低,为开展茶叶政策性农业保险提供技术支撑。%This paper takes tea production in Xinchang County of Zhejiang as an example,under the principle of disaster risk analysis and requirement for agricultural insurance,combined with characteristics such as huge topographic relief and significant difference in microclimate in southern mountain area of China,carries out risk evaluation and agricultural insurance product design through elaborating frost disaster which affected tea production in March at village township level.Firstly,the paper confirms tea's economic output changes from time to time in productive life based on tea's daily economic output in normal years of tea planting base;combined with economic loss rate due to frost during/before productive life in previous years to confirm frost weather index

  16. Soil piping in a temperate humid climate. The Flemish Ardennes (Belgium).

    Verachtert, Els

    2011-01-01

    Collapsible loess-derived soils are prone to subsurface soil erosion (piping), whereenlargement of macropores may lead to a subsurface pipe network and eventuallyto soil collapse. This PhD aimed at understanding the factors controlling theoccurrence of collapsed pipes in the Flemish Ardennes. In total, 137 parcelswith 560 collapsed pipes were mapped, indicating significant soil losses in aland use –pasture– that is typically considered to be non-susceptible to surfaceerosion. Logistic regress...

  17. On quark number susceptibilities at high temperatures

    Bazavov, A; Hegde, P; Karsch, F; Miao, C; Mukherjee, Swagato; Petreczky, P; Schmidt, C; Velytsky, A

    2013-01-01

    We calculated second and fourth order quark number susceptibilities for 2+1 flavor QCD in the high temperature region using two improved staggered fermion formulations. The calculations are performed at several lattice spacing and we show that in the continuum limit the two formulations give consistent results. We compare our continuum extrapolated results on quark number susceptibilities with recent weak coupling calculations, and find that these cannot simultaneously explain the lattice results for second and fourth order quark number susceptibilities.

  18. Does winter warming enhance cold CO2 emission from temperate continental soils?

    Kurganova, Irina; Lopes de Gerenyu, Valentin; Khoroshaev, Dmitry

    2016-04-01

    In subboreal and temperate regions, the cold season generally lasts more than 3 months of the year, influencing the carbon cycle in terrestrial ecosystems. The permanent snow pack plays an important role in the functioning of the ecosystem, especially in temperate continental regions, preventing frost penetration into the soil. The extent and duration of the permanent snow pack are predicted to decrease markedly in transitional seasons for many boreal and subboreal regions during the next 50 years. This study focused on: (i) assessment of current winter climate trends in the Moscow region pertaining to the continental temperate region, (ii) comparison of soil temperature regimes at different snow pack depths, (iii) estimation of cold CO2 fluxes from soils under various frozen regime and vegetation cover, and (iv) the contribution of freezing-thawing events to the total cold CO2 emission from soils in the temperate continental region. An experiment with regulated snow cover was established on grassland and bare soil (Luvisols Haplic, Moscow region, 54o50'N, 37o36'E; continental temperate climate). The following winter scenarios were foreseen: (1) reference plot, designated "Ref", with natural depth of snow cover, (2) no-frost, "NoFr" (simulation of deep snow cover using artificial heat insulation material), and (3) no-snow, "NoSn" (without snow cover). We observed inverse trends as the air temperature increased and precipitation decreased, which resulted in a 1-month prolongation of the snow-free period and a decrease in the snow pack over the last 20 years. Soil freezing significantly reduced the cold CO2 fluxes from soils: by 10-70% in the bare areas and by up to double that amount in the grass plots. There were six freezing-thawing cycles (FTC; 1-7 weeks' duration) from October 2014 to early April 2015, which induced CO2 emission pulses of varying intensity. The highest peaks of CO2 emission rate (3-30-fold increase compared to the pre-thawing period) were

  19. Characteristics of Frost Change and Its Influence on Main Crops in Qiemo Oasis During 1961-2010%且末绿洲1961-2010年霜冻的变化特征及其对主要农作物的影响

    黄玖君; 师国强; 邓小霞

    2013-01-01

    利用且末绿洲近50 a初、终霜日等气候资料,分析该地区的霜冻变化特征,初步探讨其对主要农作物的影响.结果表明:且末绿洲近50 a来终霜危害大于初霜,初霜冻推迟、终霜冻提前趋势明显,无霜期呈微弱延长趋势但不显著;初、终霜均具有5a、33 a的振荡周期,未来一段时期均处在偏晚期;进入21世纪以后未出现特早初霜和特晚终霜.总体上看,气候变暖使该地区霜冻灾害减少,对主要农作物的生长有利.%Based on the first and last frost dates of meteorological data in recent 50 years of Qiemo Oasis,the change of frost was analyzed and the influence on the main crops in the region were discussed.The results indicated that the last frost dates did more harm than first frost dates in past 50 years with the trend of delay of first frost dates and advancing of the last frost dates was obvious,while the frostless period was shorten little.The first and last frost dates existed the oscillation period of 5 a and 33 a and the trend of delay in future.Both specially early first frost dates and specially late last frost dates had not appearred since the 21st century.On the whole,the climate warming mitigates the frost disaster,which is favorable for the growth of main crops.

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

    Makia L. Diko

    2014-03-01

    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.

  1. Soil information requirements for humanitarian demining: the case for a soil properties database

    Das, Yogadhish; McFee, John E.; Russell, Kevin L.; Cross, Guy; Katsube, T. John

    2003-09-01

    Landmines are buried typically in the top 30 cm of soil. A number of physical, chemical and electromagnetic properties of this near-surface layer of ground will potentially affect the wide range of technologies under development worldwide for landmine detection and neutralization. Although standard soil survey information, as related to conventional soil classification, is directed toward agricultural and environmental applications, little or no information seems to exist in a form that is directly useful to humanitarian demining and the related R&D community. Thus, there is a general need for an information database devoted specifically to relevant soil properties, their geographic distribution and climate-driven variability. A brief description of the various detection technologies is used to introduce the full range of related soil properties. Following a general description of the need to establish a comprehensive soil property database, the discussion is then narrowed to soil properties affecting electromagnetic induction metal detectors - a problem of much restricted scope but of immediate and direct relevance to humanitarian demining. In particular, the complex magnetic susceptibility and, to a lesser degree, electrical conductivity of the host soil influence the performance of these widely used tools, and in the extreme instance, can render detectors unusable. A database comprising these properties for soils of landmine-affected countries would assist in predicting local detector performance, planning demining operations, designing and developing improved detectors and establishing realistic and representative test-evaluation facilities. The status of efforts made towards developing a database involving soil electromagnetic properties is reported.

  2. Spatial analysis for susceptibility of second-time karst sinkholes: A case study of Jili Village in Guangxi, China

    Zhou, Guoqing; Yan, Hongbo; Chen, Kunhua; Zhang, Rongting

    2016-04-01

    After a big karst sinkhole happened in Jili Village of Guangxi, China, the local government was eager to quantitatively analyze and map susceptible areas of the potential second-time karst sinkholes in order to make timely decisions whether the residents living in the first-time sinkhole areas should move. For this reason, karst sinkholes susceptibility geospatial analysis is investigated using multivariate spatial data, logistic regression model (LRM) and Geographical Information System (GIS). Ten major karst sinkholes related factors, including (1) formation lithology, (2) soil structure, (3) profile curvature, (4) groundwater depth, (5) fluctuation of groundwater level, (6) percolation rate of soil, (7) degree of karst development, (8) distance from fault, (9) distance from the traffic route, and (10) overburden thickness were selected, and then each of factors was classified and quantitated with the three or four levels. The LRM was applied to evaluate which factor makes significant contributions to sinkhole. The results demonstrated that formation lithology, soil structure, profile curvature, groundwater depth, ground water level, percolation rate of soil, and degree of karst development, the distance from fault, and overburden thickness are positive, while one factor, the distance from traffic routes is negative, which is deleted from LRM model. The susceptibility of the potential sinkholes in the study area is estimated and mapped using the solved impact factors. The susceptible degrees of the study area are classified into five levels, very high, high, moderate, low, and ignore susceptibility. It has been found that that both very high and high susceptibility areas are along Datou Hill and the foothills of the study area. This finding is verified by field observations. With the investigations conducted in this paper, it can be concluded that the susceptibility maps produced in this paper are reliable and accurate, and useful as a reference for local

  3. National and sub-national assessments of soil organic carbon stocks and changes: The GEFSOC modelling system

    Milne, E.; Al-Adamat, R.; Batjes, N.H.; Bernoux, M.; Bhattacharyya, T.; Cerri, C.C.; Cerri, C.E.P.; Coleman, K.; Easter, M.; Falloon, P.; Feller, C.; Gicheru, P.; Kamoni, P.; Killian, K.; Pal, D.K.; Paustian, K.; Powlson, D.; Rawajfih, Z.; Sessay, M.; Williams, S.; Wokabi, S.

    2007-01-01

    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,

  4. Assessment of soil lead exposure in children in Shenyang, China.

    Ren, H M; Wang, J D; Zhang, X L

    2006-11-01

    Soil lead pollution is serious in Shenyang, China. The paper brings together the soil work, the bioaccessibility, and the blood lead data to assess the soil lead exposure in children in Shenyang, China. Approximately 15.25% of the samples were above China Environment Protection Agency guideline concentration for soil Pb to protect human from health risk (350 mgkg(-1)). Pb concentrations varied among use scenarios. The main lead contamination sources are industry emission and automobile exhaust. Bioaccessibility also varied among use scenarios. Children, who ingested soil from industrial area, public parks, kindergarten playground, and commercial area, are more susceptible to soil lead toxicity. The industrial area soil samples presented higher bioaccessibility compared to the other use scenario soil samples contaminated by automobile exhaust. The result also suggested a most significant linear relationship between the level of Pb contamination and the amount of Pb mobilized from soil into ingestion juice. Soil pH seemed to have insignificant influence on bioaccessibility in the present study. Bioaccessibility was mainly controlled by other factors that are not investigated in this study. A linear relationship between children blood lead and soil intestinal bioaccessibility was present in the study. Children who are 4-5 years old are more likely to demonstrate the significant relationship between soil lead bioaccessibility and blood lead as their behaviors place them at greatest risk of soil lead toxicity, and their blood lead levels are more likely to represent recent exposure.

  5. Bioinduced weathering in Swedish boreal forest soil investigated by mineral amendment

    Olofsson, Madelen; Ahmed, Engy; Bylund, Dan; Holmström, Sara

    2013-04-01

    The purpose of this study was to investigate how soil mineral amendment affects microbial composition and how different mineral composition and varied depth influence these changes. Apatite, biotite and oligoclase were placed at soil horizon interfaces in a podzole in Bispgården, central Sweden (63°07'N, 16°70'E), between the summer of 2009 and 2011. Continuous measurement of soil chemistry; pH, dissolved organic carbon (DOC) and low molecular mass organic acids (LMMOAs) was performed for the surrounding soil during the frost free months of the two-year incubation period. Mineral sample surfaces were investigated using scanning electron microscopy (SEM) pre and post soil incubation to give a visual verification of weathering effects. Evaluating soil chemistry data and data received at the end of the incubation period, results show that the highest concentration of LMMOAs is found in the E horizon and that it corresponds with the highest total fungal activity in the bulk soil. Total microbial activity was found to be highest in the O horizon. Measurements on the soil of the mineral surfaces show that in all cases, apatite stimulates the microbial activity the most, followed by biotite and last oligoclase. Comparing the soil horizons, effects on total microbial activity are the highest in the E horizon, but when looking at total fungal activity the biggest changes are found in O and B horizon indicating that bacterial and fungal activities are affected differently by mineral amendment. Using ANOVA followed by pair wise comparisons according to Tukey, significant differences were found in microbial activity between the soil horizons and also between most of the different minerals, compared with the bulk soil. Looking at the SEM images taken before and after weathering, minerals placed in the O and E horizon are clearly the most affected, and the magnitude of weathering between the different minerals corresponds to the microbial activity found.

  6. Potassium Supplying Power of Soils in Heilongjiang Province and the Effect of Potassium Application on Resistance of Crops to Adverse Conditions

    ChenKuiqing; WangErli; 等

    1995-01-01

    The total potassium(K)content of soils in Heilongjiang was relatively high in general and the available potassium content on soils was quite different for different soil types.The results of electro-ultra-filtration(EUF)analysis showed that the dark brown forest soils and the black soils in the northern part contained relatively high EUF-K,ranged from 12.5 to 15.7 mg per 100g soil.In the black soils in the southern part,the EUF-K ranged from 8 to 9mg per 100g soil.The albic and aeolian sandy soils contained low EUF-K,ranged from 3.2 to 4.8mg per 100g soil.Field experiment in 1982 indicated that potassium fertilizer in soils with medium or low EUF-K,increased soybean yield by 17%-34%,and obviously prevented the epidemic of meadow moth and soybean mosaic virus.Application of potassium fertilizer increased the protein and total sugar content of the plants,promoted transportation of nutrients,speeded up the growth of the plants,improved the resistance of crops to adverse conditions.Application of potassium fertilizer resulted in early maturity of crops(4-7 days earlier than cotrol),which had great significance for preventing crops from early frost damage.Hence,in order to keep nutrients balance in the soil and to increase soil fertility.potassium fertilizer or materials containing potassium must be applied to soils with medium and low EUF-K,such as black soils in the south part,ablic soils and aeolian sandy soils in Heilongjiang Province.

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

    C. J. Westbrook

    2010-01-01

    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 key control in variable soil moisture and frost table interactions among the sites was the presence of surface water. 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 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 conductive 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.

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

    X. J. Guan

    2010-07-01

    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.

  9. 风速对空气源热泵翅片管换热器结霜特性影响%The effects of wind speed on frosting characteristics of fin - tube heat exchanger for air source heat pump

    尹从绪; 陈轶光

    2011-01-01

    The effect of the wind velocity on the frosting characteristics of the fin - and - tube heat exchanger was investigated experimentally. The experimental results indicated that the frost mass accumulation doesn't increase linearly with the wind velocity, the minimum frost mass accumulation are formed at the air velocity of 1. 3m/s. The frost thickness decreased as the wind velocity increase, but the maximum heating capacity increased as the face velocity increase.%针对风速对空气源热泵翅片管室外换热器结霜特性的影响进行了实验研究.实验结果表明,结霜量随风速的增加不是成线形增长,在风速为1.3m/s时结霜量最小.霜层厚度随着风速的增加反而减小,而翅片管换热器的最大换热量随着风速的增加而增加.

  10. Spin susceptibility of disordered gapped graphene systems

    Grosu, I.; Biter, T. L.

    2017-02-01

    We calculate the spin susceptibility for the case of gapped graphene systems in the presence of disorder. The average single-particle density of states in gapped graphene with disorder was calculated, using the Born and the T-matrix approximations. The temperature dependence of the static spin susceptibility was analyzed. The influence of the chemical potential position and disorder is also discussed.

  11. Search for new breast cancer susceptibility genes

    Oldenburg, Rogier Abel

    2008-01-01

    This thesis describes the search for new high-risk breast cancer susceptibility genes by linkage analysis. To date 20-25% of familial breast cancer is explained by mutations in the high-risk BRCA1 and BRCA2 breast cancer susceptibility genes. For the remaining families the genetic etiology is unknow

  12. Mapping markers linked to porcine salmonellosis susceptibility

    Galina-Pantoja, L.; Siggens, K.; Schriek, van M.G.M.; Heuven, H.C.M.

    2009-01-01

    The goal of this study was to identify pig chromosomal regions associated with susceptibility to salmonellosis. Genomic DNA from pig reference populations with differences in susceptibility to Salmonella enterica serovar Choleraesuis as quantified by spleen and liver bacterial colonization at day 7

  13. Effects of Variety, Fertilizer Recipe and Cultivation Mode on Frost Resistance of Potato%品种、肥料配方与栽培方式对马铃薯抗冻效果的影响

    戴亨仁; 黄家芸; 朱跃冬; 罗雪军; 赵小兵

    2011-01-01

    Frost is a disastrous climate often happened in potato production period in southern China. Using different varieties, fertilizer recipes and cultivation modes to conduct contrast test for comparing frost resistance of potato. The results showed that the differences of frost resistance among different treatments were obvious, the highest yield of potato reached 20 818.5 kg/hm2 and the lowest yield of potato only was 528 kg/hm2; the variety is the largest affecting factor for frost resistance, and the Holland No.7 has the strongest frost resistance, which can recover growth after froze to death twice, and its average yield reached 20 239.5 kg/hm2; the cultivation mode is the second affecting factor for frost resistance of potato, the yield of potato planting with double rows on a big ridge averagely increased by 6 607.5 kg/hm2 than that planting with single row on a small ridge; the fertilizer recipe is the third affecting factor for frost resistance of potato, the yield of potato applied with "two micro one free" integrated technique recipe averagely increased by 3 406.5 kg/hm2 than that applied with potato specialty fertilizer.%霜冻是南方马铃薯生产期常遇的灾害件气候.设置不同品种、肥料配方和栽培方式进行马铃薯的抗冻效果对比试验,结果表明:不同处理间抗冻效果差异显著,马铃薯最高产最达到1 387.9 kg/667m,最低产量只有35.20 kg/667m;其中品种是抗冻的最佳因子,以荷兰7号抗冻能力较强,经过两次冻死后仍能恢复生长,平均产量达1 349.3 kg/667m;其次是栽培方式,大垄双行比小垄单行平均增产440.5 kg/667m;再次是肥料配方,施用"两微一免"集成技术配方比薯类专用肥平均增产227.1 kg/667m.

  14. Comparison of seasonal soil microbial process in snow-covered temperate ecosystems of northern China.

    Xinyue Zhang

    Full Text Available More than half of the earth's terrestrial surface currently experiences seasonal snow cover and soil frost. Winter compositional and functional investigations in soil microbial community are frequently conducted in alpine tundra and boreal forest ecosystems. However, little information on winter microbial biogeochemistry is known from seasonally snow-covered temperate ecosystems. As decomposer microbes may differ in their ability/strategy to efficiently use soil organic carbon (SOC within different phases of the year, understanding seasonal microbial process will increase our knowledge of biogeochemical cycling from the aspect of decomposition rates and corresponding nutrient dynamics. In this study, we measured soil microbial biomass, community composition and potential SOC mineralization rates in winter and summer, from six temperate ecosystems in northern China. Our results showed a clear pattern of increased microbial biomass C to nitrogen (N ratio in most winter soils. Concurrently, a shift in soil microbial community composition occurred with higher fungal to bacterial biomass ratio and gram negative (G- to gram positive (G+ bacterial biomass ratio in winter than in summer. Furthermore, potential SOC mineralization rate was higher in winter than in summer. Our study demonstrated a distinct transition of microbial community structure and function from winter to summer in temperate snow-covered ecosystems. Microbial N immobilization in winter may not be the major contributor for plant growth in the following spring.

  15. Susceptibility genes in movement disorders.

    Scholz, Sonja; Singleton, Andrew

    2008-05-15

    During the last years, remarkable progress in our understanding of molecular genetic mechanisms underlying movement disorders has been achieved. The successes of linkage studies, followed by positional cloning, have dominated the last decade and several genes underlying monogenic disorders have been discovered. The pathobiological understanding garnered from these mutations has laid the foundation for much of the search for genetic loci that confer risk for, rather than cause, disease. With the introduction of whole genome association studies as a novel tool to investigate genetic variation underlying common, complex diseases, a new era in neurogenomics has just begun. As the field rapidly moves forward several new challenges and critical questions in clinical care have to be addressed. In this review, we summarize recent advances in the discovery of susceptibility loci underlying major movement disorders, explain the newest methodologies and tools employed for finding and characterizing genes and discuss how insights into the molecular genetic basis of neurological disorders will impact therapeutic concepts in patient care.

  16. Metabolic polymorphisms and cancer susceptibility.

    Smith, G; Stanley, L A; Sim, E; Strange, R C; Wolf, C R

    1995-01-01

    The vast majority of cancers arise as a consequence of exposure to environmental agents that are toxic or mutagenic. In response to this, all higher organisms have evolved complex mechanisms by which they can protect themselves from environmental challenge. In many cases, this involves an adaptive response in which the levels of expression of enzymes active in the metabolism and detoxification of the foreign chemical are induced. The best characterized of these enzyme systems are the cytochrome P450s, the GSTs and the NATs. An unfortunate consequence of many of these reactions, however, is the creation of a toxic or mutagenic reaction product from chemicals that require metabolic activation before realizing their full carcinogenic potential. Altered expression of one or more of these drug metabolizing enzymes can therefore be predicted to have profound toxicological consequences. Genetic polymorphisms with well defined associated phenotypes have now been characterized in P450, GST and NAT genes. Indeed, many of these polymorphisms have been associated with decreased or increased metabolism of many tumour promoters and chemical carcinogens and hence offer protection against or increased susceptibility to many distinct tumour types.

  17. Chiral susceptibility and the scalar Ward identity.

    Chang, L.; Liu, Y.-X.; Roberts, C. D.; Shi, Y.-M.; Sun, W.-M.; Zong, H.-S.; Physics; Inst. of Applied Physics and Computational Mathematics; Peking Univ.; National Lab. of Heavy Ion Accelerator; Univ. of New South Wales; Nanjing Univ.; Joint Center for Particle, Nuclear Physics and Cosmology

    2009-03-01

    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.

  18. Magnetic Soils Profiles in the Volga-Kama Forest-Steppe Region

    L.A. Fattakhova

    2016-09-01

    Full Text Available The magnetic properties of virgin forest-steppe soils developed on the originally vertically uniform unconsolidated parent material have been investigated. The profile samples of virgin dark-grey forest light-clayey soil derived from a siltstone of the Kazan layer of the Upper Permian and virgin leached medium-thick fertile light-clayey chernozem derived from a Quaternary heavy deluvial loam have been considered. Both soils are characterized by the accumulative type of magnetic susceptibility and F-factor values distribution patterns with depth. In the humus part of the soil profile, magnetics are present pre-dominantly in the < 2.5 µm fraction. The coercivity spectra allowed to determine the contribution of dia-/paramagnetic and ferromagnetic components to magnetic susceptibility. It has been found that magnetic susceptibility enhancement in the organogenic horizons of virgin forest-steppe soils occurs due to the contribution of ferromagnetic components. The results indicate a strong positive linear correlation between the magnetic susceptibility and oxalate-extractable Fe, as well as between the magnetic susceptibility and Schwertmann’s criterion values. Using the method of thermomagnetic analysis of the < 2.5 µm fraction, it has been found that the magnetic susceptibility enhancement in the profiles of forest-steppe soils took place due to the formation of maghemite-magnetite associations. The predominantly ferromagnetic fraction consists of small single-domain grains.

  19. 弗罗斯特《摘罢苹果》一诗的意蕴%The Meaning of Frost' s “After Apple-- Picking”

    赵芳; 张潇潇

    2012-01-01

    《摘罢苹果》是弗罗斯特田园诗的代表作之一,诗人笔下的乡村劳动充满了田园的情趣和质朴的美。文章通过诗中所体现的劳动之美和诗人所表现出的无奈和茫然的情感揭示了作者的阅历与该诗内容的关系。%“apple” is one of the representative works of Frost's pastoral poetry, the poet's rural labor with pastoral interests and simple beauty. This paper tries to find the poetry embodied in labor and the beauty of the poet shows no Nye and loss of feeling and analysis author experience and the poetry content relationship.

  20. 渠道冻胀离心模型试验设备的研制%Development of centrifugal model test facility for frost-heave of channels

    黄英豪; 蔡正银; 张晨; 徐光明; 洪建忠; 赵宝忠

    2015-01-01

    Frost-heave damage is the main reason for the channels in seasonal frozen regions. A new device is developed for simulating the frost-heave phenomenon of channels. It mainly includes the freeze-thaw model container, the circulating cooling water system and the measurement control system. The freeze-thaw model container consists of internal and external structures, and thermal insulation materials are filled between them. The circulating cooling water system adopts 12 groups of semiconductor chilling plates, and cooling or heating is accomplished by the Peltier effects. The high-pressure pump combined with the air cooling radiator realizes a continuous cooling for the system without hydraulic rotating joints. The installation device for the direct rebound displacement sensors is developed to ensure the accurate measurement. The whole device is used to study the frost-heave damage of a channel. The test results show a good regularity with correct simulation of both the temperature and displacement fields, indicating that this facility is effective for the simulation tests on frost-heave of channels.%输水渠道冻胀破坏是寒冷地区渠道破坏的主要表现。研制了一套在土工离心机中进行渠道冻胀模拟的试验设备,该设备主要包括冻融模型箱、循环冷却水系统、测量控制系统等组成。冻融模型箱采用内外两层结构,中间填充保温材料。循环冷却水系统采用12组半导体制冷片,利用其帕尔贴效应实现制冷/热。采用高压水泵驱动水流并结合风冷散热器,持续为制冷器循环冷却,实现了在离心机不具备水旋转接头下的循环水利用。开发了直流回弹式位移测量系统的安装装置,保证了测量系统的准确。利用该设备进行了北疆地区输水渠道的冻胀模拟,试验结果规律好,可以正确的模拟冻胀温度场和位移场。渠道冻胀离心模型试验设备的研制为寒冷地区输水渠道冻胀问题

  1. Frost多维完美主义量表的Rasch分析%A rasch analysis of the frost multidimensional perfectionism scale

    韩雪; 吴锐; 赵守盈

    2013-01-01

    The study reported here aimed to analyze the Frost Multidimensional Perfectionism Scale using a Rasch rating scale model.The result:All of the six subscales had unidimensionality; All of the items in the scale fitted the model well,and the point-measure correlation coefficient were acceptable consistency; The Rasch item reliability was good,but the person reliability was on the low side.%采用Rasch模型对Frost多维完美主义量表进行分析.结果表明:六个分量表均具有单维性;量表中各项目与Rasch模型拟合良好,各项目与其各自量表之间的相关度适中;六个分量表的项目信度良好,而个体信度系数偏低.

  2. Balloon-borne cryogenic frost-point hygrometer observations of water vapour in the tropical upper troposphere and lower stratosphere over India: First results

    Sunilkumar, S. V.; Muhsin, M.; Emmanuel, Maria; Ramkumar, Geetha; Rajeev, K.; Sijikumar, S.

    2016-03-01

    Balloon-borne cryogenic frost-point hygrometer (CFH) observations of water vapour in the upper troposphere and lower stratosphere (UTLS) region carried out over India, from Trivandrum [8.5°N, 76.9°E] and Hyderabad [17.5°N, 78.6°E], were compared with that obtained from quasi-collocated Aura-Microwave Limb Sounder (MLS) satellite observations. Comparisons show a small dry bias for MLS in the stratosphere. Saturated or super-saturation layers observed near the base of tropical tropopause layer (TTL) are consistent with the quasi-collocated space-based observations of tropical cirrus from KALPANA-1 and CALIPSO. Disturbance of large scale waves in the upper troposphere appears to modulate the water vapour and cirrus distribution.

  3. 不同因素对再生骨料混凝土抗冻性的影响%Effect of Different Factors on Frost Resistance of Recycled Aggregate Concrete

    陈德玉; 刘来宝; 严云; 谭克锋; 刘欢

    2011-01-01

    研究了改性和未改性再生骨料、硅灰及引气剂等因素对C40再生骨料混凝土抗冻性能的影响.结果表明:经300次冻融循环后,与天然骨料混凝土相比,随着再生骨料取代率的增加,再生混凝土的抗冻性有所下降;改性骨料能在一定程度上改善混凝土的抗冻性,有机硅防水剂改性后的再生骨料效果较好;硅灰和引气剂掺加都能较明显地改善再生混凝土的抗冻性.%The influence of modified and unmodified aggregate, silica fume and air-entraining agent on the frost resistance of C40 recycled aggregate concrete has been studied. The results show that the frost resistance of the recycled aggregate concrete with various replacement of recycled aggregate through 300 cycles of freezing and thawing, compared to natural aggregate concrete (control concrete). Moreover, the frost resistance of recycled aggregate concrete falls with the increase of the replacement of recycled aggregate. The frost resistance of recycled aggregate concrete can be improved through either addition of the modified recycled aggregate by organic-silicon or an appropriate amount of silica fume or entrained air agent, and it can be attributed to the improvement of the microstructure of recycled aggregate concrete. Silica fume and air-entraining agent can obviously improve the frost resistance of recycled aggregate concrete.

  4. 3D linear inversion of magnetic susceptibility data acquired by frequency domain EMI

    Thiesson, J.; Tabbagh, A.; Simon, F.-X.; Dabas, M.

    2017-01-01

    Low induction number EMI instruments are able to simultaneously measure a soil's apparent magnetic susceptibility and electrical conductivity. This family of dual measurement instruments is highly useful for the analysis of soils and archeological sites. However, the electromagnetic properties of soils are found to vary over considerably different ranges: whereas their electrical conductivity varies from ≤ 0.1 to ≥ 100 mS/m, their relative magnetic permeability remains within a very small range, between 1.0001 and 1.01 SI. Consequently, although apparent conductivity measurements need to be inverted using non-linear processes, the variations of the apparent magnetic susceptibility can be approximated through the use of linear processes, as in the case of the magnetic prospection technique. Our proposed 3D inversion algorithm starts from apparent susceptibility data sets, acquired using different instruments over a given area. A reference vertical profile is defined by considering the mode of the vertical distributions of both the electrical resistivity and of the magnetic susceptibility. At each point of the mapped area, the reference vertical profile response is subtracted to obtain the apparent susceptibility variation dataset. A 2D horizontal Fourier transform is applied to these variation datasets and to the dipole (impulse) response of each instrument, a (vertical) 1D inversion is performed at each point in the spectral domain, and finally the resulting dataset is inverse transformed to restore the apparent 3D susceptibility variations. It has been shown that when applied to synthetic results, this method is able to correct the apparent deformations of a buried object resulting from the geometry of the instrument, and to restore reliable quantitative susceptibility contrasts. It also allows the thin layer solution, similar to that used in magnetic prospection, to be implemented. When applied to field data it initially delivers a level of contrast

  5. Nitrous oxide production in boreal soils with variable organic matter content at low temperature – snow manipulation experiment

    M. Maljanen

    2009-05-01

    Full Text Available Agricultural soils are the most important sources for the greenhouse gas nitrous oxide (N2O, which is produced and emitted from soil also at low temperatures. The processes behind emissions at low temperatures are still poorly known. To simulate the effects of a reduction in snow depth on N2O emission in warming climate, snow pack was removed from three different agricultural soils (sand, mull, peat. Removal of snow lowered soil temperature and increased the extent and duration of soil frost which led to enhanced N2O emissions during freezing and thawing events in sand and mull soils. The cumulative emissions during the first year when snow was removed over the whole winter were 0.25, 0.66 and 3.0 g N2O-N m−2 yr−1 in control plots of sand, mull and peat soils, respectively. Without snow cover the respectively cumulative emissions were 0.37, 1.3 and 3.3 g N2O-N m−2 yr−1. Shorter snow manipulation during the second year did not increase the annual emissions. Only 20% of the N2O emission occurred during the growing season. Thus, highlighting the importance of the winter season for this exchange and that the year-round measurements of N2O emissions from boreal soils are integral for estimating their N2O source strength. N2O accumulated in the frozen soil during winter and the soil N2O concentration correlated with the depth of frost but not with the winter N2O emission rates per se. Also laboratory incubations of soil samples showed high production rates of N2O at temperatures below 0°C, especially in the sand and peat soils.

  6. High levels of nucleotide diversity and fast decline of linkage disequilibrium in rye (Secale cereale L. genes involved in frost response

    Korzun Viktor

    2011-01-01

    Full Text Available Abstract Background Rye (Secale cereale L. is the most frost tolerant cereal species. As an outcrossing species, rye exhibits high levels of intraspecific diversity, which makes it well-suited for allele mining in genes involved in the frost responsive network. For investigating genetic diversity and the extent of linkage disequilibrium (LD we analyzed eleven candidate genes and 37 microsatellite markers in 201 lines from five Eastern and Middle European rye populations. Results A total of 147 single nucleotide polymorphisms (SNPs and nine insertion-deletion polymorphisms were found within 7,639 bp of DNA sequence from eleven candidate genes, resulting in an average SNP frequency of 1 SNP/52 bp. Nucleotide and haplotype diversity of candidate genes were high with average values π = 5.6 × 10-3 and Hd = 0.59, respectively. According to an analysis of molecular variance (AMOVA, most of the genetic variation was found between individuals within populations. Haplotype frequencies varied markedly between the candidate genes. ScCbf14, ScVrn1, and ScDhn1 were dominated by a single haplotype, while the other 8 genes (ScCbf2, ScCbf6, ScCbf9b, ScCbf11, ScCbf12, ScCbf15, ScIce2, and ScDhn3 had a more balanced haplotype frequency distribution. Intra-genic LD decayed rapidly, within approximately 520 bp on average. Genome-wide LD based on microsatellites was low. Conclusions The Middle European population did not differ substantially from the four Eastern European populations in terms of haplotype frequencies or in the level of nucleotide diversity. The low LD in rye compared to self-pollinating species promises a high resolution in genome-wide association mapping. SNPs discovered in the promoters or coding regions, which attribute to non-synonymous substitutions, are suitable candidates for association mapping.

  7. Variation Characteristics of Large-scale Frost in the East Region of the Yellow River of Gansu in Recent 40 Years%近40年甘肃河东地区大范围霜冻变化特征

    杜亮亮; 陈晓燕; 杨德保; 尚可政; 王式功

    2012-01-01

    [Objective] The research aimed to study variation characteristics of large-scale frost in the east region of the Yellow River of Gansu in recent 40 years. [ Method] Based on the daily minimum temperature data at 15 meteorological stations over the east region of the Yellow River of Gansu from 1969 to 2008, according to the common climatic statistical index of frost, the variation characteristics of large-scale frost and continuous frost in the east region of the Yellow River of Gansu in recent 40 years were studied. [ Result ] Since the 1990s, the average last frost date in the east region of the Yellow River of Gansu was obviously ahead of time, and the first frost date started to obviously postpone. The advancing time of last frost date was longer than the postponing time of first frost date. The average frost-free period also obviously prolonged. The extremely early first frost date and extremely late last frost date mainly happened in the 1970s and the 1980s. The extremely late first frost date and extremely early last frost date mainly happened after the middle period of the 1990s. The extremely long frost-free period gradually started to appear frequently. In recent 40 years, the continuous frost was gradually reducing, and the strength was also declining. [ Conclusion ] The research was favorable for understanding frost climate and climatic change characteristics in the east region of the Yellow River of Gansu, and had important guidance significance for improving prediction capability of abnormal frost disaster, effectively preventing frost disaster and improving crop yield in the area.%[目的]研究近40年甘肃河东地区大范围霜冻的变化特征.[方法]利用1969 ~2008年甘肃河东地区分布较为均匀的15个站点的逐日最低温度资料,根据通用的霜冻气候统计指标,分析了近40年甘肃河东地区大范围霜冻及大范围连续性霜冻的变化特征.[结果]自20世纪90年代起,甘肃河东地区平均终霜冻

  8. A preliminary attempt to identify atmospherically-derived pollution particles in English topsoils from magnetic susceptibility measurements

    Hay, K. L.; Dearing, J. A.; Baban, S. M. J.; Loveland, P.

    This study identifies topsoils in England having increased magnetic susceptibility (xlf) values attributable to the presence of anthropogenically produced pollution particles, such as fly-ash. The database consists of 1176 topsoils taken at 10 km intervals across the whole of England, and tested for magnetic susceptibility at low and high frequencies. Soils containing significant concentrations of pollution particles were identified using two criteria; xlf (values > 0.38 10-6m3kg-1) and xfd% (values < 3%). The ‘polluted’ topsoils are located in the south-east around London, the Midlands, the north around the conurbations of Manchester, Merseyside and West Yorkshire, and in the north-east around Newcastle and Teeside. The heavy metal concentration of the soils are elevated above background levels, and have strong positive relationships with magnetic susceptibility and other magnetic parameters.

  9. Fungal communities associated with degradation of polyester polyurethane in soil.

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

    2007-09-01

    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 soil, and only a few species in the PU communities were detectable in the soil, indicating that only a small subset of the soil fungal communities colonized the PU. Soil type influenced the composition of the PU fungal communities. Geomyces pannorum and a 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.

  10. Magnetic properties of alluvial soils polluted with heavy metals

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

    2012-04-01

    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 (Příbram; 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

  11. Soil Survey Geographic (SSURGO) - Magnesic Soils

    California Department of Resources — Magnesic soils is a subset of the SSURGO dataset containing soil family selected based on the magnesic content and serpentinite parent material. The following soil...

  12. Schoolground Soil Studies.

    Doyle, Charles

    1978-01-01

    Outlined are simple activities for studying soil, which can be conducted in the schoolyard. Concepts include soil profiles, topsoil, soil sizes, making soil, erosion, slope, and water absorption. (SJL)

  13. Temporal percolation of a susceptible adaptive network

    Valdez, L D; Braunstein, L A

    2013-01-01

    In the last decades, due to the appearance of many diseases such as SARS and the H1N1 flu strain, many authors studied the impact of the disease spreading in the evolution of the infected individuals using the susceptible-infected-recovered model. However, few authors focused on the temporal behavior of the susceptible individuals. Recently it was found that in an epidemic spreading, the dynamic of the size of the biggest susceptible cluster can be explained by a temporal node void percolation [Valdez et al PLoS ONE 7, e44188 (2012)]. It was shown that the size of the biggest susceptible cluster is the order parameter of this temporal percolation where the control parameter can be related to the number of links between susceptible individuals at a given time. As a consequence, there is a critical time at which the biggest susceptible cluster is destroyed. In this paper, we study the susceptible-infected-recovered model in an adaptive network where an intermittent social distancing strategy is applied. In this...

  14. Anisotropy of the magnetic susceptibility of gallium

    Pankey, T.

    1960-01-01

    The bulk magnetic susceptibilities of single gallium crystals and polycrystalline gallium spheres were measured at 25??C. The following anisotropic diamagnetic susceptibilities were found: a axis (-0.119??0. 001)??10-6 emu/g, b axis (-0.416??0.002)??10 -6 emu/g, and c axis (-0.229??0.001) emu/g. The susceptibility of the polycrystalline spheres, assumed to be the average value for the bulk susceptibility of gallium, was (-0.257??0.003)??10-6 emu/g at 25??C, and (-0.299??0.003)??10-6 emu/g at -196??C. The susceptibility of liquid gallium was (0.0031??0.001) ??10-6 emu/g at 30??C and 100??C. Rotational diagrams of the susceptibilities in the three orthogonal planes of the unit cell were not sinusoidal. The anisotropy in the single crystals was presumably caused by the partial overlap of Brillouin zone boundaries by the Fermi-energy surface. The large change in susceptibility associated with the change in state was attributed to the absence of effective mass influence in the liquid state. ?? 1960 The American Institute of Physics.

  15. Magnetic susceptibility of tetragonal titanium dioxide

    Senftle, F.E.; Pankey, T.; Grant, F.A.

    1960-01-01

    Careful measurements have been made of the magnetic susceptibility of the rutile and anatase crystalline forms of titanium dioxide. The magnetic susceptibility of a single crystal of high-purity rutile was found to be (0.067??0.0015)??10-6 emu per gram, and was temperature-independent from 55??to 372??K. Difficulty was encountered in obtaining a good value of the magnetic susceptibility of anatase because of impurities. However, a value of 0.02??10-6 emu per gram was obtained as a maximum value for anatase powder. A discussion is given for the different values obtained for anatase and rutile. ?? 1960 The American Physical Society.

  16. Ice Lens Formation, Frost Heave, Thin Films, and the Importance of the Polar H2O Reservoir at High Obliquity

    Zent, A. P.; Sizemore, H. G.; Rempel, A. W.

    2011-01-01

    Several lines of evidence indicate that the volume of shallow ground ice in the martian high latitudes exceeds the pore volume of the host regolith. Boynton et al. found an optimal fit to the Mars Odyssey Gamma Ray Spectrometer (GRS) data at the Phoenix landing site by modeling a buried layer of 50-75% ice by mass (up to 90% ice by volume). Thermal and optical observations of recent impact craters in the northern hemisphere have revealed nearly pure ice. Ice deposits containing only 1-2% soil by volume were excavaged by Phoenix. One hypothesis for the origin of this excess ice is that it developed in situ by a mechanism analogous to the formation of terrestrial ice lenses and needle ice. Problematically, terrestrial soil-ice segregation is driven by freeze/thaw cycling and the movement of bulk water, neither of which are expected to have occurred in the geologically recent past on Mars. If however ice lens formation is possible at temperatures less than 273 K, there are possible implications for the habitability of Mars permafrost, since the same thin films of unfrozen water that lead to ice segregation are used by terrestrial psychrophiles to metaboluze and grow down to temperatures of at least 258 K.

  17. Growing plants on atoll soils

    Stone, E L; Migvar, L; Robison, W L

    2000-02-16

    year. Except on the driest of atolls, air temperature and humidity range only within limits set by the surrounding sea. There are no cold seasons, no frosts, no cold soils, no dry winds, and no periodic plagues of insects or diseases moving from miles away. Problems of soil drainage or salinity are few and easily recognized. Nor are there problems with acid soils, soil crusting, or erosion that challenge cultivators in many other areas. On the contrary, some of the black soils at the center of wide islands rank with the best soils of Russia and the American Midwest, except for their shortage of potassium and the uncertainties of rainfall. Some of these atoll soils contain more total nitrogen than many of the world's most productive agricultural soils and, in some, the total phosphorus content is so high as to be almost unbelievable--two to five tons of the element per acre. Certainly, problems exist in growing plants on atolls. There are also some special concerns not encountered in other environments, such as the wind and salt spray near shore. The two major physical limitations, however, are inadequate rainfall in some years and in many places, and soil fertility limitations. The alkaline or ''limy'' make-up of atoll soils means that a few plant nutrients, especially iron, limit growth of many introduced plants, and this is difficult to correct. As elsewhere in the world, many--but not all--atoll soils lack enough nitrogen and/or phosphorus for high yield, and all lack sufficient potassium. There is no practical way of overcoming drought except by use of tolerant plants such as coconut (ni) and Pandanus (bob), plus collection and careful use of whatever water is available. There are opportunities to overcome nutritional limitations mentioned above, first, by intensive use of all organic debris and household wastes in small gardens and, second, by use of commercial fertilizers. Imported fertilizers are expensive, certainly, but much less so on

  18. Catchment Hydrology during Winter and Spring and the Link to Soil Erosion: A Case Study in Norway

    Torsten Starkloff

    2017-02-01

    Full Text Available In the Nordic countries, soil erosion rates in winter and early spring can exceed those at other times of the year. In particular, snowmelt, combined with rain and soil frost, leads to severe soil erosion, even, e.g., in low risk areas in Norway. In southern Norway, previous attempts to predict soil erosion during winter and spring have not been very accurate owing to a lack of catchment-based data, resulting in a poor understanding of hydrological processes during winter. Therefore, a field study was carried out over three consecutive winters (2013, 2014 and 2015 to gather relevant data. In parallel, the development of the snow cover, soil temperature and ice content during these three winters was simulated with the Simultaneous Heat and Water (SHAW model for two different soils (sand, clay. The field observations carried out in winter revealed high complexity and diversity in the hydrological processes occurring in the catchment. Major soil erosion was caused by a small rain event on frozen ground before snow cover was established, while snowmelt played no significant role in terms of soil erosion in the study period. Four factors that determine the extent of runoff and erosion were of particular importance: (1 soil water content at freezing; (2 whether soil is frozen or unfrozen at a particular moment; (3 the state of the snow pack; and (4 tillage practices prior to winter. SHAW performed well in this application and proved that it is a valuable tool for investigating and simulating snow cover development, soil temperature and extent of freezing in soil profiles.

  19. Critical State of Sand Matrix Soils

    Aminaton Marto

    2014-01-01

    Full Text Available The Critical State Soil Mechanic (CSSM is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

  20. Critical state of sand matrix soils.

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803-0.998, 0.144-0.248, and 1.727-2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

  1. Geostatistical validation and cross-validation of magnetometric measurements of soil pollution with Potentially Toxic Elements in problematic areas

    Fabijańczyk, Piotr; Zawadzki, Jarosław

    2016-04-01

    Field magnetometry is fast method that was previously effectively used to assess the potential soil pollution. One of the most popular devices that are used to measure the soil magnetic susceptibility on the soil surface is a MS2D Bartington. Single reading using MS2D device of soil magnetic susceptibility is low time-consuming but often characterized by considerable errors related to the instrument or environmental and lithogenic factors. In this connection, measured values of soil magnetic susceptibility have to be usually validated using more precise, but also much more expensive, chemical measurements. The goal of this study was to analyze validation methods of magnetometric measurements using chemical analyses of a concentration of elements in soil. Additionally, validation of surface measurements of soil magnetic susceptibility was performed using selected parameters of a distribution of magnetic susceptibility in a soil profile. Validation was performed using selected geostatistical measures of cross-correlation. The geostatistical approach was compared with validation performed using the classic statistics. Measurements were performed at selected areas located in the Upper Silesian Industrial Area in Poland, and in the selected parts of Norway. In these areas soil magnetic susceptibility was measured on the soil surface using a MS2D Bartington device and in the soil profile using MS2C Bartington device. Additionally, soil samples were taken in order to perform chemical measurements. Acknowledgment The research leading to these results has received funding from the Polish-Norwegian Research Programme operated by the National Centre for Research and Development under the Norwegian Financial Mechanism 2009-2014 in the frame of Project IMPACT - Contract No Pol-Nor/199338/45/2013.

  2. Real-Time Optical Antimicrobial Susceptibility Testing

    Fredborg, Marlene; Andersen, Klaus R; Jørgensen, Erik;

    2013-01-01

    Rapid antibiotic susceptibility testing is in highly 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, introdu......Rapid antibiotic susceptibility testing is in highly 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 monoculture showed statistically significant antibiotic effect within 6 minutes and within 30 minutes...

  3. Eicosanoids influence insect susceptibility to nucleopolyhedroviruses

    Nine pharmaceutical inhibitors of eicosanoid biosynthesis (e.g., bromophenacyl bromide, clotrimazole, diclofenamic acid, esculetin, flufenamic acid, domethacin, nimesulide, sulindac, tolfenamic acid) that increased the susceptibility of the gypsy moth, Lymantria dispar (L.), to the nucleopolyhedrovi...

  4. ENVIRONMENTAL FACTORS AFFECTING BREAST CANCER SUSCEPTIBILITY

    Environmental Factors Affecting Breast Cancer SusceptibilitySuzanne. E. FentonUS EPA, ORD, MD-67 NHEERL, Reproductive Toxicology Division, Research Triangle Park, NC 27711.Breast cancer is still the most common malignancy afflicting women in the Western world. Alt...

  5. Climate change impacts on soil erosion in the Great Lakes Region

    Quantifying changes in potential soil erosion under projections of changing climate is important for the sustainable management of land resources, especially for regions dominated by agricultural land use, as soil loss estimates will be helpful in identifying areas susceptible to erosion, targeting ...

  6. Antimicrobial resistance among Pseudomonas spp. and the Bacillus cereus group isolated from Danish agricultural soil

    Jensen, Lars Bogø; Baloda, S.; Boye, Mette;

    2001-01-01

    From four Danish pig farms, bacteria of Pseudomonas spp. and the Bacillus cereus group were isolated from soil and susceptibility towards selected antimicrobials was tested. From each farm, soil samples representing soil just before and after spread of animal waste and undisturbed agricultural soil......, when possible, were collected. Soil from a well-characterized Danish farm soil (Hojbakkegaard) was collected for comparison. The Psudomonas spp. and B. cereus were chosen as representative for Gram-negative and Gram-positive indigenous soil bacteria to test the effect of spread of animal waste...... on selection of resistance among soil bacteria. No variations in resistance levels were observed between farms; but when the four differently treated soils were compared, resistance was seen for carbadox, chloramphenicol, nalidixan (nalidixic acid), nitrofurantoin, streptomycin and tetracycline for Pseudomonas...

  7. Harry Potter and the Susceptible Child Audience

    Andersen, Kara Lynn

    2005-01-01

    Kara Lynn Andersen, in her paper "Harry Potter and the Susceptible Child Audience," argues for a rethinking of assumptions of child audiences as passive readers and viewers through an analysis of the Harry Potter phenomenon. Andersen argues that instead of categorizing children as passive and homogenous subjects of analysis, they should instead be incorporated as participants in the discourse about children's books and films. Although frequently figured as especially susceptible to the affect...

  8. 铝基体超疏水表面结冰结霜特性研究%Characteristics of Ice and Frost Formation on Superhydrophobic Surfaces on Aluminum Substrates

    徐文骥; 宋金龙; 孙晶; 窦庆乐

    2011-01-01

    采用中性电解液,通过电化学加工技术及氟化处理方法制备出铝基体超疏水表面,接触角达160°,滚动角小于5°,并在其上进行了结冰和结霜研究.在不同实验条件下研究超疏水表面的形貌、霜高随时间的变化,并与相同条件下的普通铝表面、吸水性表面进行了对比.结果表明,该超疏水表面经过50多次结霜、除霜后,仍具有很好的超疏水性能,表现出良好的重复性和耐久性;与普通铝表面相比,铝基体超疏水表面具有明显的抗结冰结霜性能,霜晶先出现在四周边缘处并逐渐蔓延到中间,但抑霜能力随着冷表面温度的降低而减小;与吸水性表面相比,超疏水表面在抗结冰结霜的同时能有效抑制表面质量的增加.%The superhydrophobic surface on aluminum substrate with water contact angle of 160° and contact angle hysteresis lower than 5° was fabricated by electrochemical machining with the neutral electrolyte and fluorination, then ice and frost formation on it was studied. The surface topography and frost thickness under different experimental conditions were investigated and compared with the superhydrophobic surface, ordinary aluminum surface and hydrophilic surface, respectively. The experimental results show that the surface still has good hydrophobic properties in reproducibility and durability after SO times frost and defrosting. Moreover, the superhydrophobic surface demonstrates the anti-icing and frosting capability eminently compared with ordinary aluminum surface, frost crystals appear arounding the edge of the superhydrophobic surface firstly, then spread gradually to the entire surface, but the anti-icing and frosting capability will reduce with the decrease of temperature of cold surfaces. Furthermore, the superhydrophbic surface can prevent the increasement of ice mass effectively compared with hydrophilic surface.

  9. Agro-climatic Resources Characteristics Analysis during Frost Season in Chaoyang City%朝阳地区霜期农业气候资源特征分析

    隋景跃; 张国林

    2012-01-01

    To study the agro-climate resources changes in frost season, is to provide a scientific basis for the successful agriculture development in frost season in Chaoyang city, and to promote the favorable and avoid the unfavorable climatic resources. Based on meteorological data in Chaoyang city during 1953-2010, using the trend rate, the standard deviation statistical methods to analyze the light, heat and water resources variations. The results showed that: in the past 58 years, due to climate warming, trend of frost season shortening was obvious, and meteorological elements had different performances. Compared to data in 1950 s and 1960 s, in this nearly 20 years, temperatures in frost season increased by 2.0 ℃; sunshine time reduced by 159 h; precipitation increased by 6.6 mm; and cloudy day number changed smoothly. Rich solar energy resources, evident global warming are the agro-climatic characteristics in frost season and low natural disasters rate in frost season are very favorable to facility agriculture development.%研究霜期农业气候资源变化,为朝阳地区霜期农业顺利发展、趋利避害提供科学依据.利用朝阳1953-2010年气象资料,采用倾向率、标准偏差统计方法,分析霜期光热水资源变化特征.结果表明,近58a来,因气候变暖朝阳地区霜期缩短趋势明显,气象要素有不同的表现.与20世纪五六十年代相比,近20a里霜期气温升高2.0℃,日照时间减少159 h,降水量增加6.6 mm,阴天日数变化平稳.光能资源丰富、气候变暖明显是朝阳地区霜期农业气候特点,霜期自然灾害发生率低对霜期设施农业发展十分有利.

  10. Winter climate change affects growing-season soil microbial biomass and activity in northern hardwood forests.

    Durán, Jorge; Morse, Jennifer L; Groffman, Peter M; Campbell, John L; Christenson, Lynn M; Driscoll, Charles T; Fahey, Timothy J; Fisk, Melany C; Mitchell, Myron J; Templer, Pamela H

    2014-11-01

    Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity during the growing season. Soils from lower elevation plots, which accumulated less snow and experienced more soil temperature variability during the winter (and likely more freeze/thaw events), had less extractable inorganic nitrogen (N), lower rates of microbial N production via potential net N mineralization and nitrification, and higher potential microbial respiration during the growing season. Potential nitrate production rates during the growing season were particularly sensitive to changes in winter snow pack accumulation and winter soil temperature variability, especially in spring. Effects of elevation and winter conditions on N transformation rates differed from those on potential microbial respiration, suggesting that N-related processes might respond differently to winter climate change in northern hardwood forests than C-related processes.

  11. Snowmelt Infiltration Into Alpine Soils Visualised In Situ With A Dye Tracer Method

    Stähli, M.; Bayard, D.; Wydler, H.; Flühler, H.

    The mechanisms governing snowmelt infiltration into frozen or unfrozen alpine soils are complex due to the fact that many factors influence the flow paths from the snow pack into the soil, such as soil type, slope inclination and aspect, ground vegetation and the occurrence and persistence of ice on the soil surface or in the frozen soil. Dye tracer experiments are a feasible method to provide a better insight into the real distribution of such water flow paths, which can be very preferential. The main objec- tive of this study was to test the potential of dye tracer methods for visualising in situ snowmelt infiltration at alpine sites and to gain quantitative information on snowmelt infiltration into frozen and unfrozen soils. Field experiments were carried out during winter 2000/01 in southern Switzerland at Hannigalp (2100 m a.s.l.), where a 60 to 80 cm deep Ferric Podzole facing north-west is covered by sparse Ericaceae, and at Gd-St-Bernard pass (2500 m a.s.l.), where a shallow stony Ranker facing south is cov- ered with grass. At the beginning of December a dye tracer (Brilliant Blue FCF) was applied on the soil surface covering an area 5 m downhill x 1.5 m horizontally. At dif- ferent stages during the snowmelt (March to June) we excavated vertical soil profiles on these plots (from below upwards) and took photographs of the stained soil profiles using a digital camera. From these digital images the areas of the soil profiles stained with the dye tracer were determined using a supervised classification method, and the depth distribution of areal coverage of dye tracer was calculated. The water flow pat- tern showed to be extremely heterogeneous in the Hannigalp soil, and more uniform in the Gd-St-Bernard soil. Already in an early stage of the snowmelt we observed infil- tration down to 40 to 60 cm, indicating a relatively high soil matrix infiltration rate at Gd-St-Bernard and efficient preferential flow channels (e.g. along roots) at Hannigalp. Soil frost

  12. Effect of long-term zinc pollution on soil microbial community resistance to repeated contamination.

    Klimek, Beata

    2012-04-01

    The aim of the study was to compare the effects of stress (contamination trials) on the microorganisms in zinc-polluted soil (5,018 mg Zn kg(-1) soil dry weight) and unpolluted soil (141 mg Zn kg(-1) soil dw), measured as soil respiration rate. In the laboratory, soils were subjected to copper contamination (0, 500, 1,500 and 4,500 mg kg(-1) soil dw), and then a bactericide (oxytetracycline) combined with a fungicide (captan) along with glucose (10 mg g(-1) soil dw each) were added. There was a highly significant effect of soil type, copper treatment and oxytetracycline/captan treatment. The initial respiration rate of chronically zinc-polluted soil was higher than that of unpolluted soil, but in the copper treatment it showed a greater decline. Microorganisms in copper-treated soil were more susceptible to oxytetracycline/captan contamination. After the successive soil contamination trials the decline of soil respiration was greater in zinc-polluted soil than in unpolluted soil.

  13. Research in the Field of Salt in Freezing Soils%土体冻结过程中的盐分场研究

    邴慧; 何平; 杨成松

    2004-01-01

    As to salty soil, salt migrates with water in freezing soils, assembles and crystallizes continuously. Consequently the swelling of the soil volume leads to the phenomenon of salt heaving. It has a practical significance for solving salt-heaving and frost-heaving damage in engineering to deepen the understanding of salt heaving mechanism. In this paper a general overview about new research results at this aspect was presented. And then the study of salt migration and salt heaving mechanism and present salt heaving models were summarized. For further researching the field of salt transfer it is urgent to continually strengthen the salt migration and the numerical simulation study of salt heaving mechanism to expect perfecting the general evaluation of salt heaving prediction models so as to have a better service for engineering.

  14. Differential susceptibility experiments: going beyond correlational evidence: comment on beyond mental health, differential susceptibility articles.

    van IJzendoorn, Marinus H; Bakermans-Kranenburg, Marian J

    2012-05-01

    Reviewing the studies on differential susceptibility presented in this section, we argue that the time is ripe to go beyond correlational designs to differential susceptibility experiments. In such experiments, randomization prevents hidden moderator effects on the environment and guarantees the independence of moderator and outcome, while the environment is manipulated and assessed in standard ways. Correlational studies generate a priori expectations about crucial moderators (e.g., temperament, biological sensitivity, and genetics). We discuss the differential susceptibility experiments available up until now and conclude that these experiments are feasible and contribute in unique ways to our conceptions of differential susceptibility.

  15. 大面积果园高架长叶片防霜机的效果试验%Effective experiment of elevated wind machine for frost protection with long blade in large apple orchards

    尹宪志; 王研峰; 丁瑞津; 付双喜; 张丰伟; 陈祺

    2014-01-01

    为了验证防霜机能否对果园上方空气进行物理扰动、消除近地层逆温,基于自主研究设计的国内首台高架长叶片防霜机,利用2013年10月19-21日强降温过程中的对比试验观测数据及分析,对该防霜机防霜冻效果进行了评估。结果表明:在逆温条件下,一套功率为120 kW,高度为8.5 m,风叶直径为6 m的高架防霜机扰动混合环境内上下层空气使得保护区内逆温现象消失,近地层1~3m增温明显,防霜机保护区内相对湿度减小较快,有效防止霜冻形成;20 m左右是防霜机的强风速扰动影响区,距离地面3、2、1 m处风速分别为4.0、2.1、1.6 m/s。防霜机有效保护范围为水平20~100 m,在其范围内空间1~3 m的风速随水平距离的增大呈波动减少趋势;每台防霜机的有效保护面积为1.73~3.07 hm2。该文研究为科学高效的人工防御霜冻灾害和防霜机的技术推广提供参考。%In recent years, the crops have severely suffered from frost damage with the deterioration of the global climate. Conventional methods of frost protection, such as smoking, covering, and irrigation may be effective in many cases, but they are time-consuming, and some methods even easily caused environmental contamination. So study of scientific and high-effective artificial frost prevention equipment has become very necessary and an urgent need. Most wind machines for frost protection are still in the pilot stage at home and abroad, and their height and blade length, etc, are not for taller plants, such as apple trees,peach trees, and cherry trees. The Gansu meteorology department, using the principle of disturbing the air of mechanical power, invented the first domestic elevated wind machine for frost protection with a long blade, which proved the feasibility of frost protection by air in disturbing surface layer. The machine construction has the main components as follows:blade,pipe tower, fan

  16. Effect of Clay Content and Soil-water Potential On Mobilization and Leaching of Colloids In Unsaturated Macroporous Soil

    Kjaergaard, C.; de Jonge, L. W.; Moldrup, P.

    The transport of strongly sorbed environmental contaminants may be enhanced due to sorption to mobile soil colloids. The most common source of mobile colloids in soil is the in-situ release of water-dispersible colloids (WDC), however experimental investigations of colloid mobilization in unsaturated macroporous soil are scarce. An understanding of the arrangement of colloids in aggregates, and the influence of clay on the development of the soil fabric and pore-size distributions is essential for the in- terpretation of colloid mobilization in soils. This emphasizes the important role of clay content, when evaluating the susceptibility of soils to release colloids and associated contaminants. This study was conducted to determine the effect of clay content and initial soil- water potential on colloid mobilization and leaching. Intact soil cores were sampled from an arable field at six locations along a naturally occurring texture gradient. Soil dispersibility was investigated using capillary saturation and drainage of field-moist packed aggregates. The amount of WDC in the soil was measured for each com- bination of clay content and initial soil-water potential (-2.5, -98 and -15530 hPa). Mobilization and leaching of colloids was investigated from unsaturated intact soil cores. The soils were irrigated at low intensity (1 mm/h), and effluent sampling was conducted at 5 cm tension. The results showed that colloid dispersion was significantly affected by both clay con- tent and initial soil-water potential. With a soil-water potential of -15530 hPa the col- loid release was generally low and no variation occurred between the soils. With in- creasing soil-water potential there was an increase in the amount of WDC for all soils. The increase in WDC was negatively correlated with clay content. The leaching of colloids from intact soil cores also decreased with increasing clay content at an ini- tial soil-water potential of -98 and -2.5 hPa, and no difference between

  17. Demonstration cultivation of Salix in northern Sweden with a focus on frost resistance; Demonstrationsodling av Salix i Norrland med frosttolerans i fokus

    Soederstroem, Yvonne

    2010-06-15

    This project is part of the Thermal Engineering Research Association's (Vaermeforsk) programme 'Crops from field to energy production' and the goal is to convince growers to begin cultivating Salix in the northern part of Sweden. The project will demonstrate whether it is possible to grow Salix and examine what type of Salix (the report refers to the different types as Tora, Karin and Gudrun) is most frost-resistant and resistant to insects, fungal infections and animals. The project is aimed primarily at landowners and energy companies. The results showed that growth at the demonstration plots was moderate and the establishment rate was considered good. Growth has been uneven across the fields. At Eriksgaard, about 75% of the plants survived the winter. Survival was determined by the number of plants missing and dead. Additional plants were planted at the sites in 2009. No major insect or leaf fungus attacks were noted at either Eriksgaard or Soergaard, but they both experienced grazing from deer and elk. The rating showed that the herbicide treatment was not sufficient on the demonstration fields. For this reason, a comparison of average lengths was performed of Gudrun in Bodum, where the weeds had not grown as much. The comparison showed that the difference in growth was not significant in the autumn 2008, but the plants in Bodum had grown more by autumn 2009. Topping was not performed in the spring 2009 so that the plants would have an opportunity to grow higher than the weeds and the plants would have an opportunity to have a growth spurt. A comparison of Tora, Karin and Gudrun in Roedoen showed moderate growth for the three types. There were variations in the rows and across the field, mostly for Tora and Karin. Gudrun had lower, but more consistent growth across the field. During the summer 2009, survival was rated for the plants in Roedoen. This rating showed that 90% of Tora, 60% of Karin and 70% of Gudrun had survived the winter. The Salix

  18. Frost Hazard Risk Assessment of Winter Wheat: Based on the Meteorological Indicator at Different Growing Stages%我国冬小麦霜冻灾害致灾因子危险度评价——基于作物生育阶段气象指标

    林晓梅; 岳耀杰; 苏筠

    2009-01-01

    Frost is a meteorological disaster which is a threat to agricultural production. The research on its hazard risk can provide a basis for the large-scale agricultural disasters regionalization and agricultural insurance.According to the theory of crop growing stages, the average annual number of frost days on different degrees (light frost damage, medium frost damage, serious frost damage) in every growing stage of the winter wheat is counted and the probability of the occurrence of frost on different degrees in the whole growth of winter wheat is calculated as well based on the daily minimum temperature data and information about crop growing period of 751 meteorological stations nationwide in the period of 56 years. The winter wheat frost hazard risk degree is assessed based on the above two indicators. The result shows that the serious frost damage frost day is in a maximum of 129 days, and the light and medium frost damage frost day are respectively in a maximum of 23 days and 9 days, so that the winter wheat in China is suffered from serious frost damage for a long time. The probability of the occurrence of frost increases from south to north. With the increase of hazard risk degree, there is bttle different in the area of where there is high-frequency frost. However, the area of where there is frequent frost is decreased, and the area of low-frequency is increased. The lowest degree of frost disaster risk is mainly distributed in low-latitude provinces, such as Hainan, Guangdong, Guangxi, and Yunnan. The highest is mainly distributed in Qinghai-Tibet Plateau.%霜冻是一种威胁农业生产的气象灾害,对其致灾因子危险度的研究,可为大尺度的作物霜冻灾害区划及农业保险提供依据.根据作物生长发育的阶段性原理,以全国751个气象台站56年的逐日最低气温资料以及作物生育期资料为基础,统计得到冬小麦各个生育阶段不同灾害等级(轻霜冻、中霜冻、重霜冻)的年霜冻日数,

  19. The InterFrost benchmark of Thermo-Hydraulic codes for cold regions hydrology - first inter-comparison results

    Grenier, Christophe; Roux, Nicolas; Anbergen, Hauke; Collier, Nathaniel; Costard, Francois; Ferrry, Michel; Frampton, Andrew; Frederick, Jennifer; Holmen, Johan; Jost, Anne; Kokh, Samuel; Kurylyk, Barret; McKenzie, Jeffrey; Molson, John; Orgogozo, Laurent; Rivière, Agnès; Rühaak, Wolfram; Selroos, Jan-Olof; Therrien, René; Vidstrand, Patrik

    2015-04-01

    The impacts of climate change in boreal regions has received considerable attention recently due to the warming trends that have been experienced in recent decades and are expected to intensify in the future. Large portions of these regions, corresponding to permafrost areas, are covered by water bodies (lakes, rivers) that interact with the surrounding permafrost. For example, the thermal state of the surrounding soil influences the energy and water budget of the surface water bodies. Also, these water bodies generate taliks (unfrozen zones below) that disturb the thermal regimes of permafrost and may play a key role in the context of climate change. Recent field studies and modeling exercises indicate that a fully coupled 2D or 3D Thermo-Hydraulic (TH) approach is required to understand and model the past and future evolution of landscapes, rivers, lakes and associated groundwater systems in a changing climate. However, there is presently a paucity of 3D numerical studies of permafrost thaw and associated hydrological changes, and the lack of study can be partly attributed to the difficulty in verifying multi-dimensional results produced by numerical models. Numerical approaches can only be validated against analytical solutions for a purely thermic 1D equation with phase change (e.g. Neumann, Lunardini). When it comes to the coupled TH system (coupling two highly non-linear equations), the only possible approach is to compare the results from different codes to provided test cases and/or to have controlled experiments for validation. Such inter-code comparisons can propel discussions to try to improve code performances. A benchmark exercise was initialized in 2014 with a kick-off meeting in Paris in November. Participants from USA, Canada, Germany, Sweden and France convened, representing altogether 13 simulation codes. The benchmark exercises consist of several test cases inspired by existing literature (e.g. McKenzie et al., 2007) as well as new ones. They

  20. 品种和栽培措施对马铃薯抗冻的影响%Study on Variety and Cultivation Mode on Frost Resistance of Potato

    黄艳岚; 徐秋生; 张超凡; 张道微; 张亚

    2015-01-01

    在长沙地区对不同马铃薯品种和栽培措施进行抗冻对比试验,结果表明:品种为抗冻主因素,小区马铃薯产量均值最高为费乌瑞它15731.03 kg/hm2,其次是中薯5号,为12821.24 kg/hm2,东农303最低,仅281.64 kg/hm2;采用稻草覆盖栽培,费乌瑞它产量最高,为19609.8 kg/hm2,比中薯5号增产25.28%,东农303仅为319.65 kg/hm2,认为费乌瑞它抗冻性最强,栽培措施宜选用稻草覆盖栽培。%A comparative study on effect of various varieties and cultivation modes on frost resistance of potato in Changsha was conducted.The results showed that variety played the most important role in the protection of potato from cold dam-age.The variety Favorita had the highest treatment yield on average,15 731.03 kg/hm2 ,the yield of variety Zhongshu 5 reached to 12 821.24 kg/hm2 ,which was the second,and the variety Dongnong 303 had the lowest yield of 281.64 kg/hm2.With straw mulching cultivation mode,the variety Favorita had the highest yield of 19 609.8 kg/hm2 ,which increased by 25.28% compared with Zhongshu 5,Dongnong 303 had only 319.65 kg/hm2.Therefore,a conclusions was draw that the Favorita has the most powerful frost resistance,and the straw mulching cultivation measures is the better one.

  1. 混合骨料混凝土抗冻性能试验研究%Experimental Study on Frost Resistance Properties of Mixed Aggregate Concrete

    储建军; 霍俊芳

    2011-01-01

    通过混合骨料混凝土的快速冻融循环试验,研究了浮石替代率、聚丙烯纤维、冻融循环次数对混合骨料混凝土抗冻性能的影响.结果表明:相对动弹性模量随着浮石替代率增加而增加;对于一定范围浮石替代率的混凝土,聚丙烯纤维的掺入能够改善混凝土的抗冻性能,浮石替代率为30%,聚丙烯纤维掺量为0.9 kg/m3的混合骨料混凝土,质量损失最小;聚丙烯纤维的掺入能够抑制混合骨料混凝土的冻融损伤,提高混凝土的密实度,减小混合骨料混凝土相对动弹性模量的损失.%Through the fast freeze-thaw cycle tests of mixed aggregate concrete, the effect of pumice replacement rate, polypropylene fibers and freeze-thaw cycle time on the frost resistance properties of mixed aggregate concrete was investigated. The results show that the relative dynamic elastic modulus increase with the increase of the pumice replacement rate, and the introduction of the polypropylene fibers could improve the frost resistance of the concrete to a certain scope of the pumice replacement rate. As for this experiment, when concrete was mixed with the pumice replacement rate of 30% and the polypropylene fibers of 0. 9 kg/m3, quality loss rate was the smallest. The addition of the polypropylene fibers could refrain from the concrete freeze-thaw damage, improve the density of the concrete and reduce the relative dynamic elastic modulus loss of the concrete.

  2. 黑龙江省水稻初霜冻灾害风险区划%Frost Hazard Risk Zoning of Rice in Heilongjiang Province

    于宏敏; 姚俊英; 朱红蕊

    2011-01-01

    According to theory of crop growing stages,the rice first frost hazard risk,disaster environmental sensitivity,vulnerability of hazard-affected bodies were analyzed,the framework for disaster risk assessment was built as well as index system,method,mode and risk zoning map based on the daily minimum temperature data,frost historical disaster data,socio-economic data,GIS data and information on crop growth period of 77 meteorological stations nationwide in the period of 1961 to 2009.The result showed that south Daxinganling,Heihe,Songnen Plain and the western of Sanjiang Plain for the highest danger zone,north Daxinganling,Mudanjiang and the eastern of Sanjiang plain were the low risk zone.%根据黑龙江省水稻的生长发育期,以全省77个台站1961~2009年的逐日最低气温资料、霜冻历史灾情数据、社会经济资料、地理信息数据及作物生育期资料为基础,综合运用GIS空间分析和灾害风险评估数学方法,对水稻初霜冻致灾因子危险性、孕灾环境敏感性、承灾体易损性等多因子综合分析,构建水稻初霜冻灾害风险评价的框架、指标体系、方法与模型,绘制相应的风险区划图。结果表明:大兴安岭南部、黑河大部分地区、松嫩平原大部和三江平原西部个别地区为次高和高风险区,大兴安岭北部地区、牡丹江大部分地区、三江平原东部地区为次低和低风险区。

  3. Study on Risk Assessment of Winter Wheat Frost Damage in Huanghuai Wheat Production Zone%黄淮地区冬小麦霜冻灾害风险评估

    沈鸿; 孙雪萍; 林晓梅

    2011-01-01

    Huanghuai Region is the main production zone of winter wheat,the main food crops in China.It is vulnerable to frost disasters,and studying disaster risk on frost disaster risk in the region has practical significance for the protection of our food security.Combine with winter wheat phenophase partition and the frost indicators,extracted records on frost days based on daily minimum temperature data of 56 weather stations in the region from 1951 to 2005.Get probability disaster maps of ≥ 10%,20%,30%,40%,50% yearly reduction rate of winter wheat frost risk through IDW,based on the yearly frost days-yearly reduction rate curve,according to the information diffusion theory.Frost disaster risk of winter wheat in Huanghuai region is assessed.The main conclusions:(1) With the same disaster intensity,the risk areas were usually connected.(2) With the different disaster intensity,the high risk areas concentrated in two areas: first,northern Shandong and southern Hebei,and second,border region of Shaanxi,Shanxi and Henan.In comparison,probability of risk of low-altitude or low latitude regions was lower.(3) Frost disaster of low intensity generally had high risk probability in the region;as the intensity increases,the probability decreases.As the reduction rate caused by disaster ≥ 40%,probability of risk of most areas was below 0.1;as the reduction rate 50%,probability of most areas was below 0.001.%黄淮地区是我国主要粮食作物冬小麦的主产区,易受霜冻灾害的影响,研究该区的霜冻灾害风险对保障我国粮食安全具有现实意义。结合分区的冬小麦物候期及其霜冻指标,以该地区56个气象站点1951—2005年日最低气温为基础数据,提取霜冻日记录。并基于年霜日数-年减产率曲线,以信息扩散理论为指导,通过IDW插值得到减产率≥10%、20%、30%、40%、50%下的冬小麦霜冻灾害概率风险图,由此评估黄淮地区冬小麦霜冻灾害

  4. Laboratory Testing of Magnetic Tracers for Soil Erosion Measurement*1

    HU Guo-Qing; DONG Yuan-Jie; WANG Hui; QIU Xian-Kui; WANG Yan-Hua

    2011-01-01

    Soil erosion, which includes soil detachment, transport, and deposition, is one of the important dynamic land surface processes. The magnetic tracer method is a useful method for studying soil erosion processes. In this study, five types of magnetic tracers were made with fine soil, fly ash, cement, bentonite, and magnetic powder (reduced iron powder) using the method of disk granulation. The tracers were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow experiments to simulate the interrill and rill components of soil erosion, in order to select one or more tracers which could be used to study detachment and deposition by the erosive forces of raindrops and surface flow of water on a slope. The results showed that the five types of magnetic tracers with high magnetic susceptibility and a wide range of sizes had a range of 0.99-1.29 gcm-s in bulk density. In the interrill and rill experiments, the tracers FC1 and FC2 which consisted of fly ash and cement at ratios of 1:1 and 2:1, respectively, were transported in phase with soil particles since the magnetic susceptibility of sediment approximated that of the soil which was uneroded and the slopes of the regression equations between the detachment of sediment and magnetic tracers FC1 and FC2 were very close to the expected value of 20, which was the original soil/tracer ratio. The detachment and deposition on slopes could be accurately reflected by the magnetic susceptibility differences. The change in magnetic susceptibility depended on whether deposition or detachment occurred. However, the tracer FS which consisted of fine soil and the tracers FB1 and FB2 which consisted of fly ash and bentonite at ratios of 1:1 and 2:1, respectively, were all unsuitable for soil erosion study since there was no consistent relationship between sediment and tracer detachment for increasing amounts of runoff. Therefore, the tracers FC1 and FC2 could be used to study soil erosion by water.

  5. Three-dimensional analysis of magnetic susceptibility in areas with different type of land use

    Zawadzki, Jarosław; Fabijańczyk, Piotr

    2015-04-01

    The knowledge of the type of semivariance and its parameters such as nugget-effect, range of correlation and sill, that quantitatively characterize spatial variability of a studied environmental phenomenon, can be essential for both measurements planning and analysis of results. In particular this is the truth in the case of magnetometric measurements of soil pollution. Field magnetometry is internationally recognized as valuable, convenient and affordable tool for soil pollution screening and assessment. However, this geophysical method usually requires support of detailed statistical and geostatistical analyses. The goal of this study was to evaluate the parameters of spatial variability of soil magnetic susceptibility depending on the terrain usage. To do so, several types of study area were specially selected: forest, arable field and urban park. Some of the study areas were neighboring to each other, in order to ensure that the anthropogenic pressure was the same at each site. In order to analyze soil magnetic susceptibility in 3-dimensional space, measurements were performed on the soil surface and in soil profile, using the MS2D and MS2C Bartington instruments, respectively. MS2D measurements were performed using quasi-regular grids, and at each sample point 10 single MS2D readings were carried out in the circle with the diameter of about 2 meters. MS2C measurements were performed using soil cores collected in the field, down to the depth of about 30cm. Such approach combines the advantages of both types of measurements and allows to get deeper insight into the distribution of soil pollution. As the first step of the analysis, the semivariances of magnetic susceptibility were calculated and thoroughly modeled for all different forms of land use, on the basis of only the MS2D measurements. Then, the MS2D and MS2C measurements were jointed into one three-dimensional data set, and were used together to calculate and model the semivariances. Finally, the

  6. Whole brain susceptibility mapping using compressed sensing.

    Wu, Bing; Li, Wei; Guidon, Arnaud; Liu, Chunlei

    2012-01-01

    The derivation of susceptibility from image phase is hampered by the ill-conditioned filter inversion in certain k-space regions. In this article, compressed sensing is used to compensate for the k-space regions where direct filter inversion is unstable. A significantly lower level of streaking artifacts is produced in the resulting susceptibility maps for both simulated and in vivo data sets compared to outcomes obtained using the direct threshold method. It is also demonstrated that the compressed sensing based method outperforms regularization based methods. The key difference between the regularized inversions and compressed sensing compensated inversions is that, in the former case, the entire k-space spectrum estimation is affected by the ill-conditioned filter inversion in certain k-space regions, whereas in the compressed sensing based method only the ill-conditioned k-space regions are estimated. In the susceptibility map calculated from the phase measurement obtained using a 3T scanner, not only are the iron-rich regions well depicted, but good contrast between white and gray matter interfaces that feature a low level of susceptibility variations are also obtained. The correlation between the iron content and the susceptibility levels in iron-rich deep nucleus regions is studied, and strong linear relationships are observed which agree with previous findings.

  7. Is susceptibility to tuberculosis acquired or inherited?

    Schurr, E

    2007-02-01

    Tuberculosis is an ongoing major public health problem on a global scale. One of the striking features of the disease is that only an estimated 10% of immunocompetent persons infected by the causative pathogen Mycobacterium tuberculosis will develop clinical signs of disease. This well-established epidemiological observation has prompted an intense search for the factors that trigger advancement of infection to disease in the small proportion of susceptible individuals. Central to this search is the questions if tuberculosis patients are inherently susceptible to the disease or if disease development is promoted by specific environmental factors. It is known that genetic and non-genetic factors of both the bacterium and the host have impact on the host response to M. tuberculosis. Yet, little is known about the interaction of these different factors and the resulting impact on disease development. Recent work suggests that in addition to common host susceptibility genes a second group of susceptibility loci exists the action of which strongly depends on the individual's clinical and exposure history. The latter genes may have a very strong effect on promoting advancement from infection to disease only in specific epidemiological settings. These findings suggest that a more detailed knowledge of gene-environment interactions in tuberculosis is necessary to understand why a small proportion of individuals are susceptible to the disease whilst the majority of humans are naturally resistant to tuberculosis.

  8. Monitoring of soil moisture dynamics and spatial differences in an agricultural catchment

    Oswald, Sascha; Baroni, Gabriele; Biro, Peter; Schrön, Martin

    2015-04-01

    A novel method to observe changes in soil moisture and other water pools at the land surface is non-invasive cosmic-ray neutron sensing. This approach by its physical principles is placed between in-soil measurements and remote sensing, and retrieves values for an intermediate spatial scale of several hectars, which can be used to quantify stored water at the land surface. It detects variations in the background of neutrons, induced initially from cosmic-rays hitting the atmosphere, and this can be related to interesting quantities at the land surface, such as soil moisture, but to some degree also snow water equivalent and changes in the biomass of vegetation. In a small catchment being used as a long-term landscape observatory of the TERENO initiative we retrieved cosmic-ray neutron measurements for several years, for up to four adjacent sites. The terrain was hilly with some slopes being partly used for agricultural fields, partly grassland. Here, after atmospheric corrections and a calibration procedure soil moisture dynamics could be observed for integral soil depths of several decimeters, clearly responding to precipitation events and offering a comparison to various local and non-local soil moisture measurements there. For winter periods with frost and snow, also the water mass stored in the snow cover can be retrieved. Furthermore, observed spatial differences can be related to vegetation, terrain and soil moisture state. Also, the relation to parameters representing crop biomass and growth will be discussed in respect to the retrieved cosmic-ray neutron signals, which have an influence on the interpretation as soil moisture.

  9. Soil use and management

    Hartemink, A.E.; McBratney, A.B.; White, R.E.

    2009-01-01

    This four-volume set, edited by leading experts in soil science, brings together in one collection a series of papers that have been fundamental to the development of soil science as a defined discipline. Volume 3 on Soil Use and Management covers: - Soil evaluation and land use planning - Soil and

  10. Susceptibility-weighted imaging and quantitative susceptibility mapping in the brain.

    Liu, Chunlei; Li, Wei; Tong, Karen A; Yeom, Kristen W; Kuzminski, Samuel

    2015-07-01

    Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging.

  11. Differential Susceptibility Experiments: Going beyond Correlational Evidence--Comment on beyond Mental Health, Differential Susceptibility Articles

    van IJzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.

    2012-01-01

    Reviewing the studies on differential susceptibility presented in this section, we argue that the time is ripe to go beyond correlational designs to differential susceptibility experiments. In such experiments, randomization prevents hidden moderator effects on the environment and guarantees the independence of moderator and outcome, while the…

  12. Comparison of the Efficacy of Watermelon Frost and Cydiodine Buccal Tablets in Treatment of Oral Ulcer%西瓜霜喷剂与西地碘含片治疗口腔溃疡的疗效比较

    王宏峰

    2016-01-01

    目的:对比西瓜霜喷剂与西地碘含片治疗口腔溃疡的疗效。方法喷剂组、含片组各入选患者142例,分别采用西瓜霜喷剂、西地碘含片治疗。结果喷剂组痊愈率、愈显率高于含片组,差异具有统计学意义(P<0.05)。结论西瓜霜喷剂治疗口腔溃疡疗效更优。%Objective Comparison of watermelon frost spray and West iodine tablets in the treatment of oral ulcer curative effect. Methods Spray group, tablet group each selected 142 patients, respectively by watermelon frost spray, cydiodine buccal tablets in the treatment. Results Spray agent group, the cure rate, markedly rate is higher than the tablet group, the difference has statistical significance (P<0.05). Conclusion Watermelon frost spray in the treatment of oral cavity ulcer curative effect better.

  13. Integration of data-driven and physically-based methods to assess shallow landslides susceptibility

    Lajas, Sara; Oliveira, Sérgio C.; Zêzere, José Luis

    2016-04-01

    Approaches used to assess shallow landslides susceptibility at the basin scale are conceptually different depending on the use of statistic or deterministic methods. The data-driven methods are sustained in the assumption that the same causes are likely to produce the same effects and for that reason a present/past landslide inventory and a dataset of factors assumed as predisposing factors are crucial for the landslide susceptibility assessment. The physically-based methods are based on a system controlled by physical laws and soil mechanics, where the forces which tend to promote movement are compared with forces that tend to promote resistance to movement. In this case, the evaluation of susceptibility is supported by the calculation of the Factor of safety (FoS), and dependent of the availability of detailed data related with the slope geometry and hydrological and geotechnical properties of the soils and rocks. Within this framework, this work aims to test two hypothesis: (i) although conceptually distinct and based on contrasting procedures, statistic and deterministic methods generate similar shallow landslides susceptibility results regarding the predictive capacity and spatial agreement; and (ii) the integration of the shallow landslides susceptibility maps obtained with data-driven and physically-based methods, for the same study area, generate a more reliable susceptibility model for shallow landslides occurrence. To evaluate these two hypotheses, we select the Information Value data-driven method and the physically-based Infinite Slope model to evaluate shallow landslides in the study area of Monfalim and Louriceira basins (13.9 km2), which is located in the north of Lisbon region (Portugal). The landslide inventory is composed by 111 shallow landslides and was divide in two independent groups based on temporal criteria (age ≤ 1983 and age > 1983): (i) the modelling group (51 cases) was used to define the weights for each predisposing factor

  14. High resolution modeling of agricultural nitrogen to identify private wells susceptible to nitrate contamination.

    Hoppe, Brendalynn; White, Denis; Harding, Anna; Mueller-Warrant, George; Hope, Bruce; Main, Eric

    2014-12-01

    Given the lack of data on private wells, public health and water quality specialists must explore alternative datasets for understanding associated exposures and health risks. Characterizing agricultural nitrogen inputs would be valuable for identifying areas where well water safety may be compromised. This study incorporated existing methods for estimating nutrient loading at the county level with datasets derived from a state permitting program for confined animal feeding operations and agricultural enterprise budget worksheets to produce a high resolution agricultural nitrogen raster map. This map was combined with data on soil leachability and new well locations. An algorithm was developed to calculate nitrogen loading and leachability within 1,000 meters of each well. Wells with a nonzero nitrogen total linked to soils with high leachability were categorized and displayed on maps communicating well susceptibility across the state of Oregon. Results suggest that 4% of recently drilled wells may be susceptible to nitrate contamination, while areas identified for mitigation are too restrictive to include all susceptible wells. Predicted increases in population density and the steady addition of approximately 3,800 new wells annually may lead to a large number of residents, especially those in rural areas, experiencing long-term exposures to nitrate in drinking water.

  15. Introduction to cancer genetic susceptibility syndromes.

    McGee, Rose B; Nichols, Kim E

    2016-12-02

    The last 30 years have witnessed tremendous advances in our understanding of the cancer genetic susceptibility syndromes, including those that predispose to hematopoietic malignancies. The identification and characterization of families affected by these syndromes is enhancing our knowledge of the oncologic and nononcologic manifestations associated with predisposing germ line mutations and providing insights into the underlying disease mechanisms. Here, we provide an overview of the cancer genetic susceptibility syndromes, focusing on aspects relevant to the evaluation of patients with leukemia and lymphoma. Guidance is provided to facilitate recognition of these syndromes by hematologists/oncologists, including descriptions of the family history features, tumor genotype, and physical or developmental findings that should raise concern for an underlying cancer genetic syndrome. The clinical implications and management challenges associated with cancer susceptibility syndromes are also discussed.

  16. Magnetic Susceptibility in the Vertebral Column

    Schick, F.; Nagele, T.; Lutz, O.; Pfeffer, K.; Giehl, J.

    1994-01-01

    A magnetic resonance method is described which provides good-quality field-mapping images of the spine, although the in vivo signals from red bone marrow of the vertebral bodies exhibit similar fractions of lipid and water protons with their chemical-shift difference of 3.4 ppm. The susceptibilities of bone marrow and intervertebral disks were examined in 20 cadaveric human spines, 9 healthy volunteers, and 9 patients with degenerative disk alterations. The influence of geometrical properties was studied in cylindrical spine phantoms of different size and contents with different susceptibility. The measurements reveal interindividual differences of the susceptibility of the intervertebral disks in healthy subjects. Three out of nine degenerated disks with low signal in T2-weighted spin-echo images showed irregularities of the field distribution within the nucleus pulposus.

  17. AC susceptibilities of grain-textured superconductors

    Sakamoto, N.; Fukuda, Y.; Koga, M.; Akune, T.; Khan, H. R.; Lüders, K.

    2008-09-01

    In-phase χ n‧ and out-phase χ n″ components of nth harmonics of AC susceptibility with measuring parameters of a DC magnetic field Bdc, an amplitude Ba and a frequency f of the superimposed AC magnetic fields give substantial information of the superconducting properties. In low- Tc metallic superconductors, χ1‧ shows smooth transition and χ1″ does single peak. High- Tc oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics. Double peaks in χ1″ and shoulders in χ1‧ appear in AC susceptibility of Hg-1223 superconductors. Instead of simple Bean model, a grained model, where the superconducting grains are immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the model show varied and deformed curves and are successfully compared with the measured results.

  18. Significant relationships among frost tolerance and net photosynthetic rate, water use efficiency and dehydrin accumulation in cold-treated winter oilseed rapes.

    Urban, Milan Oldřich; Klíma, Miroslav; Vítámvás, Pavel; Vašek, Jakub; Hilgert-Delgado, Alois Albert; Kučera, Vratislav

    2013-12-15

    Five winter oilseed rape cultivars (Benefit, Californium, Cortes, Ladoga, Navajo) were subjected to 30 days of cold treatment (4 °C) to examine the effect of cold on acquired frost tolerance (FT), dehydrin (DHN) content, and photosynthesis-related parameters. The main aim of this study was to determine whether there are relationships between FT (expressed as LT50 values) and the other parameters measured in the cultivars. While the cultivar Benefit accumulated two types of DHNs (D45 and D35), the other cultivars accumulated three additional DHNs (D97, D47, and D37). The similar-sized DHNs (D45 and D47) were the most abundant; the others exhibited significantly lower accumulations. The highest correlations were detected between LT50 and DHN accumulation (r=-0.815), intrinsic water use efficiency (WUEi; r=-0.643), net photosynthetic rate (r=-0.628), stomatal conductance (r=0.511), and intracellular/intercellular CO2 concentration (r=0.505). Those cultivars that exhibited higher Pn rate in cold (and further a significant increase in WUEi) had higher levels of DHNs and also higher FT. No significant correlation was observed between LT50 and E, PRI, or NDVI. Overall, we have shown the selected physiological parameters to be able to distinguish different FT cultivars of winter oilseed rape.

  19. 风冷冰箱抗菌技术试验研究%Research on Project of Antibacterial Technology for Frost-free Refrigerator

    2012-01-01

    In order to study the antibacterial effect of frost-free refrigerator to meet the high-end consumer demand for healthy refrigerator, this paper presents a antibacterial technology, at different working conditions by controlling the start-stop time of damper and uviol lamp to test the antibacterial effect. The antibacterial experi-ment results show that it can be more effective to kill the refrigerator air and the food surface bacteria, in line with national freezer antibacterial standard requirements,.%  为了研究风冷冰箱的抗菌效果,以满足高端消费者对健康冰箱的需求,本文提出了一种在不同工作状态下,通过控制风门和紫外灯的开停时间来实现冰箱抗菌的方案。抗菌实验结果表明,这种抗菌技术能更有效地杀死冰箱中空气以及食品表面的细菌,符合国家有关冰箱抗菌标准要求。

  20. EFFECT OF FLY ASH FROM THE INCINERATION OF SEWAGE SLUDGE ON THE STRENGTH AND FROST RESISTANCE OF FINE-GRAINED CONCRETE

    Gabriela Rutkowska

    2015-11-01

    Full Text Available According to the data of Polish Central Statistical Office (GUS, 526,000 Mg. of sludge solids were produced in 2010 in Poland. Moreover, it is expected in the National Program of Municipal Wastes Treatment that the quantity of sludge in 2015 will grow till 662000 Mg. of sludge solids. It is the effect of dynamic development of the sewerage system in Poland. One of the possibilities of the recycling such ashes is their application in the production of building materials, such as grained concrete. Such solution gives ecological and economical advantages. The paper presents the results of investigations of properties (consistency, compressive strength and tensile strength after 28 and 56 days of curing, frost of grained concretes as well as the concretes containing various quantity of fly-ashes produced in the thermal recycling of municipal sludge. Concrete with addition of fly-ashes was produced in four versions. In the two ones, the quantity of ashes equal 15% and 20% of the cement mass was added and in the another two versions 15% and 20% mass of the cement was replaced by the ashes. After the investigations it was stated that the applied admixture improves the properties of the grained concrete, hence, reduces the costs of its production.