WorldWideScience

Sample records for frost susceptible soil

  1. Frost Heave in Colloidal Soils

    KAUST Repository

    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.

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

    DEFF Research Database (Denmark)

    JØrgensen, Anders Stuhr; Orlander, Tobias

    2013-01-01

    The increase in urban population in arctic areas leads to an increased demand for transportation infrastructures (such as roads and airfields) in the regions. This challenges the road constructions in terms of condition, bearing capacity and maintenance. It is believed that deicing agents used 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, Que?bec, Canada. The tests have been carried out in order to determine the frost susceptibility of the material when it is contaminated by a deicing agent. Two series of three freezing tests with isothermal cooling has been conducted using identical saline gradient added through brine. Two types of cooling ramp, an automatic cooling and a manual cooling, 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 results do not support the theory that a saline gradient effectively can replace a thermal gradient and create favorable conditions for frost heave. There was no evidence of ice segregation during the tests. During freezing, heave of maximum 0.02 % was observed which, however, is not considered 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 data on the granular subbase material. © 2013 American Society of Civil Engineers.

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

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Orlander, Tobias; Dore?, Guy

    The increase in urban population in arctic areas leads to an increased demand for transportation infrastructures (such as roads and airfields) in the regions. This challenges the road constructions in terms of condition, bearing capacity and maintenance. It is believed that deicing agents used on...... order to determine the frost susceptibility of the material when it is contaminated by a deicing agent. Two series of three freezing tests with isothermal cooling has been conducted using identical saline gradient added through brine. Two types of cooling ramp, an automatic cooling and a manual cooling...

  4. Importance of soil frost and winter climate for dissolved organic carbon (DOC) in northern boreal soils

    Science.gov (United States)

    Haei, M.; Öquist, M.; Laudon, H.

    2011-12-01

    In many northern latitude regions, riparian soils are significant sources of DOC to the adjacent streams and exert a major control on stream water chemistry. As the winter climate in northern regions is predicted to be particularly affected by climate change, it is important to investigate the sensitivity of DOC in riparian soils. We conducted an eight year field-scale soil frost manipulation experiment (deep soil frost, shallow soil frost and control) to investigate the impacts of soil frost and winter conditions on the concentration and quality of DOC in riparian soil water in a boreal forest of northern Sweden. The effect of soil freezing on DOC was further investigated in a laboratory experiment on the riparian soil samples. In the laboratory experiment, we studied several combinations of four freezing related factors: low experiment temperature, water content, experiment duration and frequency of freeze-thaw cycles. Deeper and longer soil frost significantly increased the soil water DOC concentrations (up to twice) and lability in the upper soil horizons, compared to shallower and shorter soil frost. In the laboratory experiment, similar responses of soil water DOC were observed in which the highest concentration and lability were observed in the samples incubated in the lowest temperatures (-12°C). Furthermore, fungal growth rate and soil basal respiration responded positively to soil frost induced increase in DOC concentration. The frequency of freeze-thaw cycle did not appear to be an influential factor in the laboratory experiment. Several significant interactions of the factors were also detected. In addition, we studied the alterations in soil water DOC concentrations as the soil frost expanded downwards in a mire profile during the soil frost season (Nov-May). As the soil frost deepened from Nov to Feb, the soil water DOC concentrations below the ice increased. At soil frost thaw in May, the DOC concentrations decreased to the initial levels measured at the onset of soil frost formation. In a complementary freeze-out experiment in the laboratory, we observed that DOC concentrations in the unfrozen water enhanced as the frozen proportion of the sample increased, so that the DOC concentrations doubled when 75% of the sample was frozen. Here we highlight the importance of soil frost regime and winter climatic conditions for regulating DOC in riparian forest soils and in mires in seasonally frozen soils. However, to assess the sensitivity of soil DOC to climate change, the complex interactions of air temperature, snow depth and soil frost together with changes in hydrology and soil microbial community should be taken into account.

  5. A Community Frost/Freeze Susceptibility Operational Guidance Tool

    Science.gov (United States)

    Hall, B. L.; Curtis, A.; Timlin, M.; Woloszyn, M.; Zaloudek, Z.; Hilberg, S.; Guinan, P.; Andresen, J.; Longstroth, M.; Wolf, R.; Shanklin, R.; Spoden, P.

    2013-12-01

    In response to historical costly and damaging freeze events in the north-central United States, the Midwestern Regional Climate Center (MRCC) has teamed up with the National Weather Service (NWS), State Climatologists, and land grant university Extension agricultural and horticultural specialists to develop an operational online guidance tool to help monitor, assess, and mitigate these extreme weather phenomena. The Vegetation Impact Program (VIP), hosted by the MRCC, was established in spring 2013 to provide a partnership opportunity among these stakeholders of vegetation and climate monitoring and assessment. It offers an online portal to operational assessment tools, a means of communicating status of vegetative growth and climate conditions in the region, and multiple methods of communicating between sectors and stakeholders. The Frost/Freeze Project is the first impact monitoring project within VIP and was inspired by NWS forecasters requesting help attaining decision-making assistance and guidance tools both within the NWS community and the community of vegetation experts. Early accomplishments have included: (1) the development of daily, operational climate monitoring maps based upon in situ atmospheric observations from the cooperative network (Co-op), (2) development of online guidance and impact reporting forms for VIP subscribers to submit their observations from both the field and forecasting offices, and (3) an email listserv for the VIP community to share general information. Future plans include expanding the spatial domain of the project to the 48 states, incorporating hourly observations from both national and local/state mesonets, and integrating digital forecast data real-time to provide vegetation susceptibility and risk guidance tools.

  6. Sensitivity of Soil Carbon Balances to Changes in the Extent and Duration of Soil Frost in a Boreal Forest

    Science.gov (United States)

    Oquist, M. G.; Haei, M.; Laudon, H.

    2008-12-01

    Climate change is likely to alter soil frost depth and duration in the boreal zone in the future. Soil frost can influence biogeochemical soil processes directly, for instance by altering rates of microbial decomposition of soil organic matter (SOM) and by increasing root mortality. In addition, soil frost controls hydrologic flow paths, which in turn determines export of carbon from soils to surface waters, primarily during high-flood events associated with snow melt and soil thawing. Nonetheless, to what extent changes in soil frost regimes influences the soil C dynamics is poorly understood. Here we present results from a field manipulation investigation with three soil frost treatments (deep soil frost, shallow soil frost and ambient controls; n = 3) that has been in operation for 7 years. Increased soil frost depth results in decreased soil CO2 concentrations and soil respiration rates during the following growing season. We see a strong correlation between the maximum soil frost depth during winter and the amount of C lost from the system by soil respiration (R = 0.99) suggesting that average soil respiration rates during the growing season will decrease by ca 0.01 g CO2 m-2 day-1 for every 1 cm increase in soil frost depth. This corresponds to up to 0.5% of the estimated annual net ecosystem productivity. Because year-to-year variation in soil frost depth at the site varies by up to 60 cm, we conclude that it can constitute an important control on soil C balances. Results also show a significant effect on the pool of dissolved organic carbon (DOC) in the soil during spring thaw and early summer, where deep soil frost treatments show up to twice the amount of DOC, as compared to shallow soil frost treatments. In addition, laboratory incubations suggest that alterations in winter soil temperatures and soil frost distribution also affects the composition of the DOC pool altering its aromaticity, with potential effects on its bioavailability. Thus, a change in soil frost regime has implications for both the amount and the composition of C exported from soils to surface waters.

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

    Science.gov (United States)

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

    2015-08-01

    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.

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

    OpenAIRE

    Bayard, Daniel

    2003-01-01

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

  9. Significance of frost action and surface soil characteristics to wind erosion at Rocky Flats, Colorado. Third progress report, October 1, 1976--June 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Caine, N.; Morin, P.; Nicholas, R.M.

    1977-01-01

    This report summarizes information on soil frost effects collected on Rocky Flats during the 1976 and 1977 winter. The work has continued on two scales as in the previous two winters. Empirical surveys along 4 line transects during the second half of the winter support earlier conclusions that the frost susceptibility of the Rocky Flats soils is well keyed to topography. This has been used in testing a mapping procedure for potential soil frost activity in the entire Rocky Flats area. Instrumental records of weather and soil conditions have been maintained throughout the winter at the Lindsay Ranch study site, northwest of the Rocky Flats Plant. During the winter, 9 frost heave events have been recorded and are described here. This represents a low frequency of soil disturbance by frost and is accounted for by the drought conditions on the Colorado Piedmont during 1976 and 1977. Even the events which occurred were of relatively slight magnitude, a further reflection of the lack of soil moisture during the period.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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. PMID:26452333

  12. Orchard floor management utilizing soil-applied coal dust for frost protection. Part 1. Potential microclimate modification on radiation frost nights

    Energy Technology Data Exchange (ETDEWEB)

    Sharratt, B.S.; Glenn, D.M.

    1988-06-01

    Little is known of the microclimate differences in orchards posed by different floor management systems. Comparisons were made of microclimatic factors on eight radiation frost nights in the spring of 1986 between two adjacent. 1.4 ha peach (Prunus persica (L.) Batsch) plots in the Shenandoah Valley of West Virginia. The two plots were under different floor management systems; one plot with a complete grass cover (grass plot) and the other plot consisted of alternating 3-m-wide soil, 3-m-wide grass strips with coal dust applied to the soil strip of the tree row (coal dust plot). The net radiative flux (R/sub n/) on radiation frost nights from the coal dust plot was 10-15 W m/sup -2/ lower (greater radiative loss) than from the grass plot. Only 50% of this R/sub n/ difference in the early morning hours at the beginning of this study was accounted for by the soil heat flux (G) difference. However, G accounted for an increased percentage of the R/sub n/ difference in the early morning hours as the study progressed, reaching 100% at approximately 30 days from the commencement of this study. Because the differences in R/sub n/ and G were nearly equal during radiation frost nights, it is apparent that little of the energy liberated by the soil was intercepted by the canopy. Provided a means of trapping the energy from the soil in the canopy can be devised, a potential 2-3 degrees C difference in canopy temperature may be realized between these floor management systems for the site studied. These differences in canopy temperature, however would be site-specific due to the effect of aspect, slope, relative position on slope, and vegetation on solar energy partitioning. 12 refs.

  13. Algal colonization of deglaciated and frost heaved soils in the Abisko region (subarctic Sweden).

    Czech Academy of Sciences Publication Activity Database

    Lukešová, Alena; Elster, Josef; Vá?a, J.; Štursová, H.

    Strasbourgh : CAREX Project Office, European Science Foundation, 2009, s. 28-29. [Identification of Model Ecosystems in Extreme Environments. Sant Feliu de Guixoles (ES), 30.11.2008-02.12.2008] R&D Projects: GA MŠk ME 945; GA MŠk ME 934; GA MŠk LA341 Grant ostatní: The Royal Swedish Academy of Sciences(SE) FP6 506004 Institutional research plan: CEZ:AV0Z60660521; CEZ:AV0Z60050516 Keywords : algal colonization * deglaciated and frost heaved soils * Abisko region Subject RIV: EH - Ecology, Behaviour

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

    Directory of Open Access Journals (Sweden)

    R. M. Nagare

    2011-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Crusting susceptibility in some allic Colombian soils

    International Nuclear Information System (INIS)

    Many lab methods were used: dry and water soil aggregates stability, instability index and erosion index and their results were related with soil characteristics like texture, Fe and Al oxides and organic matter. Soil samples collected within 0-2.5 and 2.5-5 cm of the soil surface came from terrains with many kinds of both forest and savanna intervened systems. Those results were analyzed like a completely randomized designed. It was found that significative changes in oxides content could increase soil-crusting susceptibility unless soil humus was up to was up to 4%. In this sense, pastures or its rotation with rice and leguminous offer a best alternative for intervening these natural systems. Intensive land husbandry or monocultures with low stubble soil incorporation caused an increase in physical instability at the top of soil. Dry soil stability test and instability index were most adequate for these soils

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  18. Soil frost-induced soil moisture precipitation feedback over high northern latitudes

    Science.gov (United States)

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

    2016-02-01

    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 impact of the currently observed warming, which is projected to persist during the coming decades due to anthropogenic CO2 input, certainly has effects for the vast permafrost areas of the high northern latitudes. The quantification of these effects, however, is scientifically still an open question. This is partly due to the complexity of the system, where several feedbacks are interacting between land and atmosphere, sometimes counterbalancing each other. Moreover, until recently, many global circulation models (GCMs) and Earth system models (ESMs) lacked the sufficient representation of cold region physical soil processes in their land surface schemes, especially of the effects of freezing and thawing of soil water for both energy and water cycles. Therefore, it will be analysed in the present study how these processes impact large-scale hydrology and climate over northern hemisphere high latitude land areas. For this analysis, the atmosphere-land part of MPI-ESM, ECHAM6-JSBACH, is 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 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 of soil moisture leads to a positive land atmosphere 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 in the research focus over the high latitudes. These results point out the importance of high latitude physical processes at the land surface for the regional climate.

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

    Energy Technology Data Exchange (ETDEWEB)

    Goulet, France

    2000-07-01

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

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

    International Nuclear Information System (INIS)

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

  1. Hydrochemical dynamics of stream water during snowmelt under differing soil frost regimes in a northern hardwood forest

    Science.gov (United States)

    Fuss, C. B.; Driscoll, C. T.; Green, M. B.; Groffman, P. M.

    2012-12-01

    Winter climate change is expected to alter the snowpack accumulation as well as the timing and magnitude of snowmelt events in northern hardwood forests. Additionally, lower snowpacks associated with climate change have been hypothesized to increase soil freezing events. Soil freezing has been associated with increases in acidity and the leaching of nitrate, but the observed effects are inconsistent, especially when comparing the plot and watershed scales. Snowmelt is a large portion of the annual hydrologic flux in northern hardwood forest catchments and characterized by acidic conditions, which can be deleterious for downstream water quality. The objectives of our study were to characterize the hydrochemical dynamics longitudinally within watersheds under differing climatic conditions and to determine if inconsistencies in observed responses to soil freezing can be explained by changes in hydrologic flowpaths associated with soil frost. We measured major solute chemistry in daily stream water samples collected throughout the snowmelt periods of 2010, 2011, and 2012 at the Hubbard Brook Experimental Forest, NH, USA. Samples were collected at the gauging station of three different watersheds (two south-facing and one north-facing) and at a higher elevation site (approximately 100 m higher than the gauging station) in one south-facing and one north-facing watershed). This sampling scheme was designed to take advantage natural differences in snow depth and soil freezing between and within watersheds. We found generally more acidic drainage water with greater flushing of nitrate (NO3-) and dissolved organic carbon (DOC) in the higher elevation sampling sites of the watersheds. Changes in solute chemistry with flow rate were more pronounced at the base of the watershed where the deeper soil profile at lower elevation allowed for more variation in hydrologic flowpaths compared to the shallow higher elevation soils. For example, changes in stream NO3- concentration associated with increases in flow during snowmelt were as much as 200% greater at the base of the watersheds compared to changes at higher elevation. Using data from soil water, shallow ground water, and snowpack, we are performing end-member mixing analysis (EMMA) to quantify the relative contribution of each source to stream water in order to characterize the hydrologic flowpaths throughout the course of snowmelt. We expect the results of the EMMA to show that the presence of soil frost attenuates lateral flow through shallow soil horizons during peak snowmelt. Our study indicates that the chemistry of snowmelt is the result of a complex set of biogeochemical and hydrological processes and that knowledge of the climatic and physical differences among subcatchments is important to understand how the northern hardwood forest is responding to winter climate change. We demonstrate that understanding the influence of soil frost on hydrology is necessary to interpret plot study soil freezing results and how they are used for larger scale predictions.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Frost evolution in tailings

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    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 of the road system. According to new specification; the size of large stones for this layer should be maximum 0.5 m (longest edge) or ½ layer thickness. And minimum 30% of stones should be less than 90 mm. Fines content (size will affect heat exchange in the layer, secondly - if the allowable fines content will make the materials frost susceptible. For calculations of frost protection layer thickness the knowledge of thermal conductivity of the aggregate layers is required. Handbook for geotechnical investigations of the soils provides this data for natural gravel which is limited by 0.7 - 1.3 W/mK. But when it comes to the crushed rocks, it can be significantly increased due to the higher conductivity of minerals (especially if they contain high amount of quartz), as well as due to higher effective conductivity. In rock-fill materials, i.e. materials with large particles and low degree of saturation, convection and radiation are the predominant heat transfer mechanisms. Convection and radiation can increase the effective conductivity by factor 2-10. Lebeau and Konrad (2007) showed that convection heat transfer could lead to the formation of undesirable permafrost conditions in toe drains of embankment dams located in Northern Quebec, i.e. in areas where there are no naturally occurring permafrost soils. In a frost design method the required parameter values of crushed rock aggregates are thermal conductivity, density and water content. The heat transfer during the freezing of natural soils is assumed proportional to thermal conductivity of the material. In a coarse-grained material with abundant pore space, convective heat transfer and radiation may be a considerable factor, sometimes even more significant than conduction. Specifications used by pavement engineers in most countries are solely based on grain size distribution and allowable fines content. The presence of fines in these layers can modify their frost susceptibility and cause severe degradation, especially with recent trends in climate change leading to more freeze-thaw cycle events during the winter season (Konrad & Lemieux, 2005). A higher content of fines due to sub-base wear will increase moisture in the structure and the risk of subsequent frost heave. Guthrie and Hermansson (2003) showed by laboratory tests in a closed drainage system that retained water in a soil sample was sufficient to feed the frost heave. Even though the most severe frost heave in real pavements occurs when the material is in contact with free water (open drainage system) we wanted to study freezing behaviour in aggregate materials having initial water contents (closed drainage system). The study presented here is part of a larger research program to investigate the properties of crushed rock materials in relation to frost heaving in the frost protection layer. An important issue will be the resistivity for frost penetration due to presence of water and fine particles. Due to new requirements for allowed fines content, it's essential to investigate if increased amount of stones samples with fines contents of 5%, 10% and 15% respectively were subjected to freezing in constant temperature. Also we made calculations for thermal conductivity by using Johansen's (1975) model. The study led to the following results: 1. Even for a closed system, without access of water, frost heave can occur just from redistributing water if the following conditions are met: a) Fines content exceeds 10%, b) Water content is around 7% 2. As to frost susceptibility classification, the crushed rock aggregates with 5% and 10% of fine material, fraction less than 0.063 mm, show negligible and/or low frost susceptibility. Those with 15% show medium frost susceptibility 3. Dry thermal conductivity for crushed rock samples, estimated by using Johansen's model, showed that an increase of dry density of 15% led to an increase of thermal conductivity of 75%. 4. Latent heat of fusion for all samples shows significant dependence on the water content, and less on the density 5. Highest calculated frost penetration depth was observed for dry samples. For other samples no big variation was found between 4% and 7% water content.

  5. Susceptibility of ectomycorrhizal fungi to soil heating.

    Science.gov (United States)

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

    2010-01-01

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

  6. Robert Frost on Writing.

    Science.gov (United States)

    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 practical…

  7. Orchard floor management utilizing soil-applied coal dust for frost protection. Part II. Seasonal microclimate effect

    Energy Technology Data Exchange (ETDEWEB)

    Sharratt, B.S.; Glenn, D.M.

    1988-07-01

    Orchard floor management has been found to affect the microclimate on radiation frost nights; however, long-term effects of management on the seasonal microclimate have not been studied. Comparisons were made of microclimatic factors in the spring of 1986 between two adjacent 1.4 ha peach (Prunus persica (L.) Batsch) plots in the Shenandoah Valley of West Virginia. The orchard floor of one plot has grass maintained in both the 3-m-wide tree row and 3-m-wide grass alley (grass plot); the floor of the other plot was similar except that coal dust was applied to the soil surface of the tree row (coal dust plot). Net radiative (R/sub n/), soil heat (G), and sensible heat flux were greater during the daytime in the coal dust plot. Averaged over the 55-day period of this study, the daily R/sub n/ and G was 7 and 2 W m/sup -2/ greater in the coal dust plot, respectively. Thus, G accounted for 30% of R/sub n/ on a daily basis. Daily average tree-row air (to 195 cm) and soil (to 5 cm) temperatures were approx. 0.2 and 2.5 degrees C higher, respectively, in the coal dust plot. The cumulative differences found at the end of this study indicated that the coal dust plot absorbed 32 MJ more net radiant energy than the grass plot. Cumulative G differences accounted for 9 MJ (30%) of the R/sub n/ difference, with a greater heat flux into the soil in the coal dust plot. An approximate difference of 130 growing-degree-hours (GDH), which represented a 1% difference, was found at the end of the study. However, at the time of bloom, which required 4000 GDH, only a 40 GDH difference was found. These results indicate that microclimatic differences between management systems are cumulative and that differences for the site studied can develop by late spring. In years with greater cloud-free days, even larger microclimatic differences could develop than those reported in this study. 8 refs., 2 figs., 1 tab.

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

    OpenAIRE

    Rahnama Yami E. et al.

    2012-01-01

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

  9. Seasonal Frost in Terra Sirenum

    Science.gov (United States)

    2006-01-01

    This image of the Terra Sirenum region of Mars was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 0918 UTC (4:18 a.m. EST) on Nov. 25, 2006, near 38.9 degrees south latitude, 195.9 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 18 meters (60 feet) across. At this time, Mars' southern hemisphere was experiencing mid-winter. During Martian southern winter, the southern polar cap is covered and surrounded by carbon dioxide frost and water frost. This is unlike Earth, whose frozen winter precipitation is made up of only one volatile -- water. The carbon dioxide frost evaporates, or sublimates, at a lower temperature than water frost. So, during spring, the carbon dioxide ice evaporates first and leaves a residue of water frost, which later sublimates as well. The image shown here covers part of a crater rim, which is illuminated from the upper left. North is at the top. The topography creates a cold microenvironment on the south side of the rim that is partially protected from solar illumination. That cold surface contains an outlier of the southern seasonal frost about 15 degrees of latitude closer to the equator than the average edge of the frost at this season. The top image was constructed from three infrared wavelengths that highlight the bluer color of frost than the background rock and soil. Note that the frost occurs both on sunlit and shaded surfaces on the south side of the rim. The shaded areas are still visible because they are illuminated indirectly by the Martian sky. The bottom image was constructed by measuring the depths of spectral absorption bands due to water frost and carbon dioxide frost, and displaying the results in image form. Blue shows strength of an absorption due to water frost near 1.50 micrometers, and green shows strength of an absorption due to carbon dioxide frost near 1.45 micrometers. Red shows brightness of the surface at 1.33 micrometers -- outside of the frost absorption bands -- in order to show the relationship of frost to the illuminated crater rim. In comparing the top and bottom images, note that water frost occurs in many locations on the south-facing side of the crater rim, both in sunlit and shaded areas. Because it faces away from the sun, this side of the crater rim is colder than the north, sun-facing side. This favors the formation of frost. In contrast, carbon dioxide frost occurs only in the coldest, most shaded areas. CRISM's mission: Find the spectral fingerprints of aqueous and hydrothermal deposits and map the geology, composition and stratigraphy of surface features. The instrument will also watch the seasonal variations in Martian dust and ice aerosols, and water content in surface materials -- leading to new understanding of the climate. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is one of six science instruments on NASA's Mars Reconnaissance Orbiter. Led by The Johns Hopkins University Applied Physics Laboratory, the CRISM team includes expertise from universities, government agencies and small businesses in the United States and abroad.

  10. Discriminating between biotic and abiotic contributions to CO2 efflux from perm?frost soil

    Directory of Open Access Journals (Sweden)

    Albina A. Danilova

    2014-08-01

    Full Text Available The rate of carbon dioxide efflux (CDE from permafrost cryoarid floodplain sandy loam soil were determined without roots and crop residues contribution. The research site was located at the Experimental Station “Marhinsky” near the city of Yakutsk (62°08´51´´N 129°45´45´E. Fallow systems: conventional (CnF, found in 2003 where weeds were removed by cultivation and conservation (CnsF, found in 2008 – where soil has not been treated after ploughing perennial grasses and weeds were removed manually. CDE was measured in one week intervals during growing season using static chamber methodology. Each chamber (n=3 was placed in the middle of a square with 1m side length. CO2 was absorbed by 1n NaOH and the amount of C-CO2 was determined by titration. The duration of each exposition amounted to 48 hours. Cumulative production of C-CO2 was calculated on the basis of daily average speed of CO2 emissions by the method of linear interpolation. In the CnF from 6th to 11th year of the experiment (2008-2013 CDE was about 800-900 kg/ha annually during the vegetation period. In CnsF after the first year of ploughing up CDE amounted 2,500 + 190 (mean + 095 confidence interval, in the next 2-5 years has stabilized at a level of 1,500+150 kg C-CO2 ha-1. In the 6th year (2013, which was characterized by an unusually early warm spring (2 weeks earlier than average and humid summer (annual norm was exceeded in 1.5 times, CDE on the CnsF reached 2,100+150 kg C-CO2 ha-1. In CnF changes were not detected. Thus, in the present climatic conditions of Central Yakutia lower steady state of CDE from the investigated soil makes up about 800 – 900, the upper level makes up 1300 – 1500 kg C-CO2 ha-1. The increase in CO2 production by soil with increasing warmth and moisture vegetation period (approximately 500 kg C-CO2 ha-1 was negated by the same increase carbon sequestration in plant biomass.

  11. Frost formation and ice adhesion on superhydrophobic surfaces

    OpenAIRE

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

    2010-01-01

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

  12. Soil Cations Influence Bryophyte Susceptibility to Bisulfite

    OpenAIRE

    BHARALI, BHAGAWAN; BATES, JEFFREY W.

    2002-01-01

    The hypothesis that metal ions absorbed by bryophytes from the underlying soil may ameliorate adverse effects of SO2 was investigated in the terricolous moss species Pleurozium schreberi (Brid.) Mitt. and Rhytidiadelphus triquetrus (Hedw.) Warnst. Dilute sodium bisulfite solutions (equivalent to dissolved SO2) were applied to shoots isolated from soil or in contact with artificial substrata. Marked inhibition of net photosynthesis was observed within 2 h of treatment with 0·3 mm bisulfite in ...

  13. Assessing Biodegradation Susceptibilities of Selected Petroleum Hydrocarbons at Contaminated Soils

    OpenAIRE

    Markus Heryanto Langsa

    2010-01-01

    The susceptibility to biodegradation of selected saturated hydrocarbons (SHCs), polycyclic aromatichydrocarbons (PAHs) and asphaltenes in a Barrow crude oil and extracts isolated from soils contaminated with theBarrow crude oil at day 0 and 39 was determined. Soil samples were contaminated with a Barrow crude oil across thesurface (5% w/w) as part of a mesocosm experiment in order to mimic similar conditions in the environment. Theextent of biodegradation of the Barrow oil extracted from the ...

  14. Use of magnetic susceptibility for evaluation of soil erosion at two locations with different soil types.

    Czech Academy of Sciences Publication Activity Database

    Kapi?ka, Aleš; Grison, Hana; Petrovský, Eduard; Jakšík, O.; Kodešová, R.

    Sofia : STEF92 Technology, 2015, s. 417-423. ISBN 978-619-7105-37-7. ISSN 1314-2704. [International multidisciplinary scientific geoconference SGEM 2015 /15./. Albena (BG), 18.06.2015-24.06.2015] Institutional support: RVO:67985530 Keywords : magnetic susceptibility * soil erosion * field test Subject RIV: DF - Soil Science

  15. Evaluation on almond flower tolerance to frosts by chlorophyl fluorescence

    OpenAIRE

    Kodad, O.; Morales Iribas, Fermín; Socías, Rafael

    2010-01-01

    Most almond cultivars are susceptible to negative temperatures, a limiting factor for almond expansion to regions with risks of spring frosts. As a consequence, the main objective of most almond breeding programmes is to select late- or very late-blooming genotypes, in order to avoid the periods of high frost risk. Flower and fruitlet tolerance to frosts has been only studied so far by observing the morphological damages produced by low temperatures. Thus, our objective was the evaluation of ...

  16. Machine learning modelling for predicting soil liquefaction susceptibility

    OpenAIRE

    Samui, P.; Sitharam, T. G.

    2011-01-01

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

  17. Frost risks in the Mantaro river basin

    Directory of Open Access Journals (Sweden)

    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.

  18. Frost heave in He

    International Nuclear Information System (INIS)

    Frost heave occurs in various phenomena in natural environment. It has been studied in helium on porous glasses under perfect ice-segregation condition. The maximum frost heave pressure was investigated for various conditions and was in good agreement with the thermodynamical prediction. The dynamical properties of frost heave are discussed and some of the preliminary results of the growth rate measurement are presented. (orig.)

  19. Assessing Biodegradation Susceptibilities of Selected Petroleum Hydrocarbons at Contaminated Soils

    Directory of Open Access Journals (Sweden)

    Markus Heryanto Langsa

    2010-01-01

    Full Text Available The susceptibility to biodegradation of selected saturated hydrocarbons (SHCs, polycyclic aromatichydrocarbons (PAHs and asphaltenes in a Barrow crude oil and extracts isolated from soils contaminated with theBarrow crude oil at day 0 and 39 was determined. Soil samples were contaminated with a Barrow crude oil across thesurface (5% w/w as part of a mesocosm experiment in order to mimic similar conditions in the environment. Theextent of biodegradation of the Barrow oil extracted from the contaminated soils at day 0 and day 39 was assessed byGC-MS analyses of SHCs and PAHs fractions. Changes in the relative abundances of n-alkanes (loss of low-molecularweighthydrocarbons and pristane relative to phytane (Pr/Ph and their diastereoisomers were determined. Changesin the diastereoisomer ratios of Pr and Ph relate to the decrease in abundance of the phytol-derived 6(R,10(Sisoprenoids with increasing biodegradation. The percentage change in abundances of each of selectedalkylnaphathalenes with time (day 0 to 39 was determined, enabling an order of susceptibility of their isomers tobiodegradation. It was established that the 2-methylnaphthalene isomers (2-MN is more susceptible to microbialattack than 1-MN isomer indicated by decreasing in percent abundance from day 0 to 39 for the 2-MN isomer. TheGC-MS analyses of the original Barrow oil indicated the oil had not undergone biodegradation. When this oil wasused in the soil mesocosm experiments the oil was shown to biodegrade to about a level 2 -3 based on the biodegradationsusceptibility of the various SHCs and PAHs described above

  20. Machine learning modelling for predicting soil liquefaction susceptibility

    Directory of Open Access Journals (Sweden)

    P. Samui

    2011-01-01

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

  1. Soil magnetic susceptibility: A quantitative proxy of soil drainage for use in ecological restoration

    Science.gov (United States)

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

    2008-01-01

    Flooded, saturated, or poorly drained soils are commonly anaerobic, leading to microbially induced magnetite/maghemite dissolution and decreased soil magnetic susceptibility (MS). Thus, MS is considerably higher in well-drained soils (MS typically 40-80 ?? 10-5 standard international [SI]) compared to poorly drained soils (MS typically 10-25 ?? 10-5 SI) in Illinois, other soil-forming factors being equal. Following calibration to standard soil probings, MS values can be used to rapidly and precisely delineate hydric from nonhydric soils in areas with relatively uniform parent material. Furthermore, soil MS has a moderate to strong association with individual tree species' distribution across soil moisture regimes, correlating inversely with independently reported rankings of a tree species' flood tolerance. Soil MS mapping can thus provide a simple, rapid, and quantitative means for precisely guiding reforestation with respect to plant species' adaptations to soil drainage classes. For instance, in native woodlands of east-central Illinois, Quercus alba , Prunus serotina, and Liriodendron tulipifera predominantly occur in moderately well-drained soils (MS 40-60 ?? 10-5 SI), whereas Acer saccharinum, Carya laciniosa, and Fraxinus pennsylvanica predominantly occur in poorly drained soils (MS restoration of mesic, wet mesic, and wet prairie species to pre-settlement distributions at Meadowbrook Park (Urbana, IL, U.S.A.). Through use of soil MS maps calibrated to soil drainage class and native vegetation occurrence, restoration efforts can be conducted more successfully and species distributions more accurately reconstructed at the microecosystem level. ?? 2008 Society for Ecological Restoration International.

  2. Enhanced by Frost

    Science.gov (United States)

    2005-01-01

    30 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of south polar layered terrain. Their appearance in this July 2005 springtime image is enhanced by bright patches of carbon dioxide frost. The frost is left over from the previous southern winter season; by summer, the frost would be gone. Location near: 84.6oS, 203.5oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  3. Polygons in Martian Frost

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-428, 21 July 2003This June 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polygonal pattern developed in seasonal carbon dioxide frost in the martian southern hemisphere. The frost accumulated during the recent southern winter; it is now spring, and the carbon dioxide frost is subliming away. This image is located near 80.4oS, 200.2oW; it is illuminated by sunlight from the upper left, and covers an area 3 km (1.9 mi) across.

  4. Performance of WEPP energy-based routine for simulating snow and soil frost in the Pacific Northwest, USA

    Science.gov (United States)

    The unique winter climate of the Northwestern Wheat and Range Region (NWRR) of the Pacific Northwest USA creates a challenge for modeling snow accumulation and melt and interaction with soil freezing and thawing. The climate has sometimes been described as Mediterranean with 55 to 65 % of the annual...

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

    Indian Academy of Sciences (India)

    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.

  6. Frost on Mars

    Science.gov (United States)

    2008-01-01

    This image shows bluish-white frost seen on the Martian surface near NASA's Phoenix Mars Lander. The image was taken by the lander's Surface Stereo Imager on the 131st Martian day, or sol, of the mission (Oct. 7, 2008). Frost is expected to continue to appear in images as fall, then winter approach Mars' northern plains. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Evaluation of almond flower tolerance to frosts by chlorophyll fluorescence

    OpenAIRE

    Kodad, Ossama; Socias i Company, Rafel; Morales Iribas, Fermín

    2011-01-01

    Most almond cultivars are susceptible to negative temperatures, a limiting factor for almond expansion to regions with risks of spring frosts. Flower and fruitlet tolerance to frosts has only been studied so far by observing the morphological damages produced by low temperatures. Thus, our objective was the evaluation of chlorophyll fluorescence (CF) to estimate the tolerance of 12 commercial almond cultivars of different origin to low temperatures. Flowers were maintained for 24 hours at dif...

  8. The possibilities of using magnetic susceptibility measurements for evaluating degradation of erosion affected soils.

    Czech Academy of Sciences Publication Activity Database

    Jakšík, O.; Kodešová, R.; Kapi?ka, Aleš; Dlouhá, Šárka; Bayarsaikhan, S.; Fér, M.; Klement, A.

    Bratislava : ÚH SAV, 2013 - (?elková, A.), s. 92-97 ISBN 978-80-89139-30-9. [Stav poznania vo výskume v hydrologických vedách. Smolenice (SK), 23.09.2013-25.09.2013] R&D Projects: GA MZe QJ1230319 Institutional support: RVO:67985530 Keywords : soil erosion * soil degradation * magnetic susceptibility * terrain properties Subject RIV: DF - Soil Science

  9. Tints, Shades and Frost

    Science.gov (United States)

    Sterling, Joan

    2009-01-01

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

  10. Frost-covered dunes

    Science.gov (United States)

    1999-01-01

    MOC image of dunes in Chasma Boreale, a giant trough in the north polar cap. This September 1998 view shows dark sand emergent from beneath a veneer of bright frost left over from the northern winter that ended in July 1998.

  11. Enhancement of MS2D Bartington point measurement of soil magnetic susceptibility

    Science.gov (United States)

    Fabijańczyk, Piotr; Zawadzki, Jarosław

    2015-04-01

    Field magnetometry is fast method used to assess the potential soil pollution. The most popular device 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. Typically, in order to calculate the reliable average value of soil magnetic susceptibility, a series of MS2D readings is performed in the sample point. As it was analyzed previously, such methodology makes it possible to significantly reduce the nugget effect of the variograms of soil magnetic susceptibility that is related to the micro-scale variance and measurement errors. The goal of this study was to optimize the process of taking a series of MS2D readings, whose average value constitutes a single measurement, in order to take into account micro-scale variations of soil magnetic susceptibility in proper determination of this parameter. This was done using statistical and geostatistical analyses. The analyses were performed using field MS2D measurements that were carried out in the study area located in the direct vicinity of the Katowice agglomeration. At 150 sample points 10 MS2D readings of soil magnetic susceptibility were taken. Using this data set, series of experimental variograms were calculated and modeled. Firstly, using single random MS2D reading for each sample point, and next using the data set increased by adding one more MS2D reading, until their number reached 10. The parameters of variogram: nugget effect, sill and range of correlation were used to determine the most suitable number of MS2D readings at sample point. The distributions of soil magnetic susceptibility at sample point were also analyzed in order to determine adequate number of readings enabling to calculate reliable average soil magnetic susceptibility. 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. References: Zawadzki J., Magiera T., Fabijańczyk P., 2007. The influence of forest stand and organic horizon development on soil surface measurement of magnetic susceptibility. Polish Journal of Soil Science, XL(2), 113-124 Zawadzki J., Fabijańczyk P., Magiera T., Strzyszcz Z., 2010. Study of litter influence on magnetic susceptibility measurements of urban forest topsoils using the MS2D sensor. Environmental Earth Sciences, 61(2), 223-230.

  12. Limits of out-of-phase susceptibility in magnetic granulometry of rocks and soils.

    Czech Academy of Sciences Publication Activity Database

    Hrouda, F.; Pokorný, J.; Chadima, Martin

    2015-01-01

    Ro?. 59, ?. 2 (2015), s. 294-308. ISSN 0039-3169 Institutional support: RVO:67985831 Keywords : out-of-phase susceptibility * frequency-dependent susceptibility measurement accuracy * environmetal magnetism * loess * soil * paleoclimatic reconstruction Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.806, year: 2014

  13. Polygons in Seasonal Frost

    Science.gov (United States)

    2004-01-01

    8 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a summertime scene in the south polar region of the red planet. A patch of bright frost--possibly water ice--is seen in the lower third of the image. Polygon patterns that have developed in the ice as it sublimes away can be seen; these are not evident in the defrosted surfaces, so they are thought to have formed in the frost. This image is located near 82.6oS, 352.5oW. Sunlight illuminates this scene from the upper left; the image covers an area 3 km (1.9 mi) wide.

  14. Frost in Charitum Montes

    Science.gov (United States)

    2003-01-01

    MGS MOC Release No. MOC2-387, 10 June 2003This is a Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle view of the Charitum Montes, south of Argyre Planitia, in early June 2003. The seasonal south polar frost cap, composed of carbon dioxide, has been retreating southward through this area since spring began a month ago. The bright features toward the bottom of this picture are surfaces covered by frost. The picture is located near 57oS, 43oW. North is at the top, south is at the bottom. Sunlight illuminates the scene from the upper left. The area shown is about 217 km (135 miles) wide.

  15. Frost on Dunes

    Science.gov (United States)

    2005-01-01

    18 March 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark dunes on a crater floor during the southern spring. Some of the dunes have frost on their south-facing slopes. Location near: 52.3oS, 326.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  16. Water frost on Charon

    Science.gov (United States)

    Buie, Marc W.; Cruikshank, Dale P.; Lebofsky, Larry A.; Tedesco, Edward F.

    1987-01-01

    New spectra of the Pluto-Charon system taken just before and during a total eclipse of the satellite are presented. The spectrum of Charon extracted from the data reveals the signature of water ice. There is no evidence for any methane or ammonia frost on the surface of Charon. The significance of these findings for the evolution of the Pluto-Charon system are discussed.

  17. The periglacial engine of mountain erosion - Part 1: Rates of frost cracking and frost creep

    Science.gov (United States)

    Andersen, J. L.; Egholm, D. L.; Knudsen, M. F.; Jansen, J. D.; Nielsen, S. B.

    2015-10-01

    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 is easily distinguished by its characteristic fjords and U-shaped valleys, the periglacial fingerprint is more subtle but potentially prevails in some mid- to high-latitude landscapes. Previous models have advocated a frost-driven control on debris production at steep headwalls and glacial valley sides. 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 present a new model that quantifies two key physical processes: frost cracking and frost creep, as a function of both temperature and sediment thickness. Our results yield new insights into how climate and sediment transport properties combine to scale the intensity of periglacial processes. The thickness of the soil mantle strongly modulates the relation between climate and the intensity of mechanical weathering and sediment flux. Our results also point to an offset between the conditions that promote frost cracking and those that promote frost creep, indicating that a stable climate can provide optimal conditions for only one of those processes at a time. Finally, quantifying these relations also opens up the possibility of including periglacial processes in large-scale, long-term landscape evolution models, as demonstrated in a companion paper.

  18. Using VNIR-DRS and magnetic susceptibility to predict soil organic carbon content.

    Czech Academy of Sciences Publication Activity Database

    Klement, A.; Kapi?ka, Aleš; Jakšík, O.; Kodešová, R.; Grison, Hana

    Sofia : STEF92 Technology, 2015, s. 425-430. ISBN 978-619-7105-37-7. ISSN 1314-2704. [International multidisciplinary scientific geoconference SGEM 2015 /15./. Albena (BG), 18.06.2015-24.06.2015] Institutional support: RVO:67985530 Keywords : visible and near infrared diffuse reflectance spectroscopy * magnetic susceptibility * soil organic carbon Subject RIV: DF - Soil Science

  19. Importance of winter climate and soil frost for dissolved organic carbon (DOC) in boreal forest soils and streams : - implications for a changing climate

    OpenAIRE

    Haei, Mahsa

    2011-01-01

    Dissolved organic carbon (DOC) is a defining feature of surface waters in a large part of the world and it influences a variety of physical, chemical and biological processes in aquatic ecosystems. Riparian soils exert a major control on stream water chemistry in many northern latitude regions and provide a local source of DOC to adjacent streams. As the winter climate in northern regions is predicted to be particularly affected by climate change, it is important to investigate the sensitivit...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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.

  2. Seasonal Frost Changes on Mars

    Science.gov (United States)

    2003-01-01

    Observations by NASA's 2001 Mars Odyssey spacecraft show a comparison of wintertime (left) and summertime (right) views of the north polar region of Mars in intermediate-energy, or epithermal, neutrons. The maps are based on data from the high-energy neutron detector, an instrument in Odyssey's gamma-ray spectrometer suite. Soil enriched by hydrogen is indicated by the purple and deep blue colors on the maps. Progressively smaller amounts of hydrogen are shown in the colors light blue, green, yellow and red. The hydrogen is believed to be in the form of water ice. In some areas, the abundance of water ice is estimated to be up to 90% by volume. In winter, much of the hydrogen is hidden beneath a layer of carbon dioxide frost (dry ice). In the summer, the hydrogen is revealed because the carbon dioxide frost has dissipated. A shaded-relief rendition of topography is superimposed on these maps for geographic reference.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson, and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency and Institute for Space Research (IKI), which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Winter Frost and Fog

    Science.gov (United States)

    2005-01-01

    This somewhat oblique blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 174 km (108 mi) diameter crater, Terby, and its vicinity in December 2004. Located north of Hellas, this region can be covered with seasonal frost and ground-hugging fog, even in the afternoon, despite being north of 30oS. The subtle, wavy pattern is a manifestation of fog. Location near: 28oS, 286oW Illumination from: upper left Season: Southern Winter

  4. Sand Dunes with Frost

    Science.gov (United States)

    2004-01-01

    9 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of frost-covered sand dunes in the north polar region of Mars in early spring, 2004. The dunes indicate wind transport of sand from left to right (west to east). These landforms are located near 78.1oN, 220.8oW. This picture is illuminated by sunlight from the lower left and covers an area about 3 km (1.9 mi) across.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Frost-free Dunes

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03291 Frost-free Dunes These dark dunes are frost covered for most of the year. As southern summer draws to a close, the dunes have been completely defrosted. Image information: VIS instrument. Latitude -66.6N, Longitude 37.0E. 34 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  7. Modelling susceptibility of grassland soil to macropore flow

    Science.gov (United States)

    Alaoui, Abdallah

    2015-06-01

    Investigating preferential flow, including macropore flow, is crucial to predicting and preventing point sources of contamination in soil, for example in the vicinity of pumping wells. With a view to advancing groundwater protection, this study aimed (i) to quantify the strength of macropore flow in four representative natural grassland soils on the Swiss plateau, and (ii) to define the parameters that significantly control macropore flow in grassland soil. For each soil type we selected three measurement points on which three successive irrigation experiments were carried out, resulting in a total of 36 irrigations. The strength of macropore flow, parameterized as the cumulated water volume flowing from macropores at a depth of 1 m in response to an irrigation of 60 mm h-1 intensity and 1 h duration, was simulated using the dual-permeability MACRO model. The model calibration was based on the key soil parameters and fine measurements of water content at different depths. Modelling results indicate high performance of macropore flow in all investigated soil types except in gleysols. The volume of water that flowed from macropores and was hence expected to reach groundwater varied between 81% and 94% in brown soils, 59% and 67% in para-brown soils, 43% and 56% in acid brown soils, and 22% and 35% in gleysols. These results show that spreading pesticides and herbicides in pumping well protection zones poses a high risk of contamination and must be strictly prohibited. We also found that organic carbon content was not correlated with the strength of macropore flow, probably due to its very weak variation in our study, while saturated water content showed a negative correlation with macropore flow. The correlation between saturated hydraulic conductivity (Ks) and macropore flow was negative as well, but weak. Macropore flow appears to be controlled by the interaction between the bulk density of the uppermost topsoil layer (0-0.10 m) and the macroporosity of the soil below. This interaction also affects the variations in Ks and saturated water content. Further investigations are needed to better understand the combined effect of all these processes including the exchange between micropore and macropore domains.

  8. Spring frost vulnerability of sweet cherries under controlled conditions

    Science.gov (United States)

    Matzneller, Philipp; Götz, Klaus-P.; Chmielewski, Frank-M.

    2016-01-01

    Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar `Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations.

  9. Spring frost vulnerability of sweet cherries under controlled conditions.

    Science.gov (United States)

    Matzneller, Philipp; Götz, Klaus-P; Chmielewski, Frank-M

    2016-01-01

    Spring frost is a significant production hazard in nearly all temperate fruit-growing regions. Sweet cherries are among the first fruit varieties starting their development in spring and therefore highly susceptible to late frost. Temperatures at which injuries are likely to occur are widely published, but their origin and determination methods are not well documented. In this study, a standardized method was used to investigate critical frost temperatures for the sweet cherry cultivar 'Summit' under controlled conditions. Twigs were sampled at four development stages ("side green," "green tip," "open cluster," "full bloom") and subjected to three frost temperatures (-2.5, -5.0, -10.0 °C). The main advantage of this method, compared to other approaches, was that the exposition period and the time interval required to reach the target temperature were always constant (2 h). Furthermore, then, the twigs were placed in a climate chamber until full bloom, before the examination of the flowers and not further developed buds started. For the first two sampling stages (side green, green tip), the number of buds found in open cluster, "first white," and full bloom at the evaluation date decreased with the strength of the frost treatment. The flower organs showed different levels of cold hardiness and became more vulnerable in more advanced development stages. In this paper, we developed four empirical functions which allow calculating possible frost damages on sweet cherry buds or flowers at the investigated development stages. These equations can help farmers to estimate possible frost damages on cherry buds due to frost events. However, it is necessary to validate the critical temperatures obtained in laboratory with some field observations. PMID:26022603

  10. Frost on Mars Rover Opportunity

    Science.gov (United States)

    2004-01-01

    Frost can form on surfaces if enough water is present and the temperature is sufficiently low. On each of NASA's Mars Exploration Rovers, the calibration target for the panoramic camera provides a good place to look for such events. A thin frost was observed by Opportunity's panoramic camera on the rover's 257th sol (Oct. 13, 2004) 11 minutes after sunrise (left image). The presence of the frost is most clearly seen on the post in the center of the target, particularly when compared with the unsegmented outer ring of the target, which is white. The post is normally black. For comparison, note the difference in appearance in the image on the right, taken about three hours later, after the frost had dissipated. Frost has not been observed at Spirit, where the amount of atmospheric water vapor is observed to be appreciably lower. Both images were taken through a filter centered at a wavelength of 440 nanometers (blue).

  11. Dunes with Frost

    Science.gov (United States)

    2004-01-01

    31 May 2004 Springtime for the martian northern hemisphere brings defrosting spots and patterns to the north polar dune fields. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example located near 76.7oN, 250.4oW. In summer, these dunes would be darker than their surroundings. However, while they are still covered by frost, they are not any darker than the substrate across which the sand is slowly traveling. Dune movement in this case is dominated by winds that blow from the southwest (lower left) toward the northeast (upper right). The picure covers an area about 3 km (1.9 mi) across and is illuminated by sunlight from the lower left.

  12. Robert Frost: Teacher "Earner, Learner, Yearner."

    Science.gov (United States)

    Vogel, Nancy Sue

    An account of Robert Frost's teaching, along with an assessment of it, are presented. Material consulted includes Frost's published letters, prose, and poetry; Lawrance Thompson's authorized biography; Lesley Frost's "New Hampshire's Child: The Derry Journals of Lesley Frost;" and additional sources such as films and periodicals, particularly…

  13. Geostatistical Microscale Study of Magnetic Susceptibility in Soil Profile and Magnetic Indicators of Potential Soil Pollution

    OpenAIRE

    Zawadzki, Jarosław; Fabijańczyk, Piotr; Magiera, Tadeusz; Rachwał, Marzena

    2015-01-01

    Directional variograms, along the soil profile, can be useful and precise tool that can be used to increase the precision of the assessment of soil pollution. The detail analysis of spatial variability in the soil profile can be also an important part of the standardization of soil magnetometry as a screening method for an assessment of soil pollution related to the dust deposition. The goal of this study was to investigate the correlation between basic parameters of spatial correlations of m...

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

    OpenAIRE

    Nadal Romero, Estela; Verachtert, Els; Poesen, Jean

    2009-01-01

    Piping has been observed in both natural and anthropogenic landscapes, in different clirnates, lithologies and soils, as weil 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 wat...

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

    International Nuclear Information System (INIS)

    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

  16. GIS-based soil liquefaction susceptibility map of Mumbai city for earthquake events

    Science.gov (United States)

    Mhaske, Sumedh Yamaji; Choudhury, Deepankar

    2010-03-01

    The problem of liquefaction of soil during seismic event is one of the important topics in the field of Geotechnical Earthquake Engineering. Liquefaction of soil is generally occurs in loose cohesionless saturated soil when pore water pressure increases suddenly due to induced ground motion and shear strength of soil decreases to zero and leading the structure situated above to undergo a large settlement, or failure. The failures took place due to liquefaction induced soil movement spread over few square km area continuously. Hence this is a problem where spatial variation involves and to represent this spatial variation Geographic Information System (GIS) is very useful in decision making about the area subjected to liquefaction. In this paper, GIS software GRAM++ is used to prepare soil liquefaction susceptibility map for entire Mumbai city in India by marking three zones viz. critically liquefiable soil, moderately liquefiable soil and non liquefiable soil. Extensive field borehole test data for groundwater depth, standard penetration test (SPT) blow counts, dry density, wet density and specific gravity, etc. have been collected from different parts of Mumbai. Simplified procedure of Youd et al. (2001) is used for calculation of factor of safety against soil liquefaction potential. Mumbai city and suburban area are formed by reclaiming lands around seven islands since 1865 till current date and still it is progressing in the area such as Navi Mumbai and beyond Borivali to Mira road suburban area. The factors of safety against soil liquefaction were determined for earthquake moment magnitude ranging from Mw = 5.0 to 7.5. It is found that the areas like Borivali, Malad, Dahisar, Bhandup may prone to liquefaction for earthquake moment magnitude ranging from Mw = 5.0 to 7.5. The liquefaction susceptibility maps were created by using GRAM++ by showing the areas where the factor of safety against the soil liquefaction is less than one. Proposed liquefaction susceptibility map of Mumbai city can be used by researchers for earthquake hazard analysis, for the preventive measures in disaster management, for urban planning and further development of Mumbai city and suburban area.

  17. Magnetic susceptibility and Heavy metals distribution from risk-cultivated soil around the iron-steel plant, China

    International Nuclear Information System (INIS)

    Magnetic susceptibility is a non-conventional way that can be used for evaluating proxy soil heavy metals pollution. The paper monitors available heavy metals (Cu, Fe, Zn, and Mn) present in cultivated soils around iron-steel plant by soil magnetic susceptibility. Our study was located in an area with high pollution with small grid density of 250 m in China. Results showed that low field magnetic susceptibility was significantly correlated with available Cu, Zn, and Mn. No clear association exists between magnetic susceptibility and available Fe, soil organic matter, pH. Frequency dependent susceptibility >5% suggests the possible presence of super-paramagnetic particles, fly ashes produced during coal combustion. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Soil loss and landslide susceptibility evaluations at the Hills of Freisa Vineyards (Central Piedmont, Northwestern Italy)

    OpenAIRE

    DESTEFANIS, Enrico; MASCIOCCO, LUCIANO; AJASSA, Roberto; MANDRONE, GIUSEPPE; CAVIGLIA, CATERINA

    2011-01-01

    In the paper, the potential soil loss and the landslides susceptibility have been evaluated means of empirical models at one of the hilly sites candidate as “Typical Piedmont Vineyard Landscapes: Langhe, Monferrato, Roero” to the World Heritage List of UNESCO. The study area is defined as “Core 1 – Freisa” and its territory is included within the municipalities of Albugnano, Castelnuovo Don Bosco, Moncucco Torinese and Pino d’Asti all in the Asti district. It is located along the north-wes...

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Device for determining frost depth and density

    Science.gov (United States)

    Huneidi, F.

    1983-08-01

    A hand held device having a forward open window portion adapted to be pushed downwardly into the frost on a surface, and a rear container portion adapted to receive the frost removed from the window area are described. A graph on a side of the container enables an observer to determine the density of the frost from certain measurements noted. The depth of the frost is noted from calibrated lines on the sides of the open window portion.

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

    International Nuclear Information System (INIS)

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

  2. Frost Multidimensional Perfectionism Scale-Deutsch

    OpenAIRE

    Stoeber, Joachim

    1995-01-01

    Die Frost Multidimensional Perfectionism Scale-Deutsch (FMPS-D; Stöber, 1995) ist die deutsche Version der Multidimensional Perfectionism Scale von Frost, Marten, Lahart und Rosenblate (1990) und erfasst Perfektionismus entlang der von Frost et al. (1990) vorgeschlagenen sechs Dimensionen: Sorge über Fehler (engl.: Concern over Mistakes, CM), Handlungszweifel (Doubts about Actions, D), Elterliche Erwartungen (Parental Expectations, PE), Elterliche Kritik (Parental Criticism, PC), Persönliche ...

  3. Cave development by frost weathering

    Science.gov (United States)

    Oberender, Pauline; Plan, Lukas

    2015-01-01

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

  4. Models of frequency-dependent susceptibility of rocks and soils revisited and broadened

    Science.gov (United States)

    Hrouda, František

    2011-12-01

    Mathematical models of the frequency-dependent susceptibility in rocks, soils and environmental materials have been adapted to measurements performed with multiple operating frequencies (465, 976, 3904, 4650, 15 616, 100 000 and 250 000 Hz) on the basis of log-normal volume distribution of magnetic particles. The XFD parameter depends, in addition to the amount of SP particles, also on the operating frequencies, whose values should be therefore also presented. The model curves of the XFD parameter versus arithmetical mean (?) of the logarithms of grain volume are roughly bell-like shaped. The width and peak position of these curves is controlled by mean and standard deviation of the logarithmic volume distribution. Magnetic susceptibility contributions from paramagnetic minerals, and from ferrimagnetic particles not belonging to a unimodal SP/SD volume distribution, tend to decrease the XFD parameter. Therefore, low XFD values do not therefore necessarily indicate low amount of SP particles, but can also be indicative of the presence of the paramagnetic fraction. A new parameter XR is introduced based on susceptibility measurements at three operating frequencies; it is insensitive to dia- and paramagnetic fractions and helps us to differentiate between wide and narrow size distributions of ferromagnetic particles. A new XFB parameter is introduced that originates through normalizing the XFD parameter by the difference of natural logarithms of operating frequencies and related to the decade difference between the frequencies. It is convenient for comparison of the Bartington MS-2 Susceptibility Meter data with the MFK1-FA Kappabridge data.

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

    Scientific Electronic Library Online (English)

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

    2008-12-01

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

  6. Identification of Soil Bacteria Susceptible to TiO2 and ZnO Nanoparticles

    Science.gov (United States)

    Ge, Yuan; Schimel, Joshua P.

    2012-01-01

    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-TiO2 and nano-ZnO, at various doses (0, 0.5, 1.0, and 2.0 mg g?1 soil for TiO2; 0.05, 0.1, and 0.5 mg g?1 soil for ZnO) in incubated soil microcosms. These ENPs significantly altered the bacterial communities in a dose-dependent manner, with some taxa increasing as a proportion of the community, but more taxa decreasing, indicating that effects mostly reduced diversity. Some of the declining taxa are known to be associated with nitrogen fixation (Rhizobiales, Bradyrhizobiaceae, and Bradyrhizobium) and methane oxidation (Methylobacteriaceae), while some positively impacted taxa are known to be associated with the decomposition of recalcitrant organic pollutants (Sphingomonadaceae) and biopolymers including protein (Streptomycetaceae and Streptomyces), indicating potential consequences to ecosystem-scale processes. The latter was suggested by a positive correlation between protease activity and the relative abundance of Streptomycetaceae (R = 0.49, P = 0.000) and Streptomyces (R = 0.47, P = 0.000). Our results demonstrate that some metal oxide nanoparticles could affect soil bacterial communities and associated processes through effects on susceptible, narrow-function bacterial taxa. PMID:22798374

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

    KAUST Repository

    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.

  8. Mapping Statistical Characteristics of Frosts in Iran

    Directory of Open Access Journals (Sweden)

    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 occurrence of the first frost day in Iran showed that the occurrence of the first frost day in Iran could be of the type of radiation frosts and the dominant role of elevation and latitude demonstrated that late-winter frosts can be mostly of the type of advection frosts. Therefore, arrangement of statistical features of frost in Iran is both a function of geo – climate factors and the synoptic systems which have entered the country.

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

    Science.gov (United States)

    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. PMID:25154685

  10. Comparative study of top soil magnetic susceptibility variation based on some human activities

    Scientific Electronic Library Online (English)

    M. O., Kanu; O. C., Meludu; S. A., Oniku.

    2014-12-01

    Full Text Available Se realizó una investigación sobre el efecto que tienen algunas actividades humanas en la susceptibilidad magnética y la susceptibilidad dependiente de la frecuencia: el estudio se realizó en Jalingo, estado de Taraba, Nigeria, en la superficie del suelo de una zona comercial, un estacionamiento de [...] autos y una zona escolar. El objetivo fue evaluar la variación de la susceptibilidad magnética con distintos tipos de uso de la tierra y detectar los puntos más contaminados utilizando los parámetros de proxy magnéticos. Con ello se evaluó la contribución de superparamagnéticas (SP), del tamaño de un grano, a la susceptibilidad magnética del cálculo de la dependencia de la frecuencia de la susceptibilidad magnética (MS). Los resultados de las mediciones de masa específicos de susceptibilidad de baja frecuencia magnética mostraron una mejora significativa con valores que van desde 67,8 hasta 495,3 x 10-8 m³kg-1, con un valor medio de 191,61 x 10-8 m³kg-1 para el Colegio Jalingo de Educación (datos JCOE); 520,1-1612,8 x 10-8 m³kg-1 con un valor medio de 901,34 x 10-8 m³kg-1 para el mercado principal de Jalingo (JMM) y 188.5- 1.203,6 x 10-8m³kg-1 con un valor promedio de 574 92 x 10-6 m³kg-1 para el Motor Park Jalingo (JMP). La mejora magnética significativa indica una alta concentración de minerales ferrimagnéticos en el suelo y, por lo tanto, un aumento en la contaminación. La susceptibilidad magnética de los diferentes usos del suelo estudiados se redujo en la zona comercial (mercado)>, estacionamiento > e instalaciones escolares. Los resultados de la dependencia del porcentaje de la susceptibilidad dependiente de la frecuencia mostró que la mayoría de las muestras tenían una mezcla de SP y los granos gruesos o de dominio de múltiples granos SP Abstract in english An investigation of the effect of some human activities on the magnetic susceptibility and frequency dependent susceptibility was conducted on top soil samples from, a commercial area, a motor park and a school environment in Jalingo, Taraba State, N-E Nigeria. The purpose was to assess the variatio [...] n of magnetic susceptibility with different land use, detect pollution hotspots using magnetic proxy parameters and evaluate the contribution of superparamagnetic (SP) grain size contribution to the magnetic susceptibility from calculation of the frequency dependence of magnetic susceptibility (MS). The results of the mass specific low frequency magnetic susceptibility measurements showed significant enhancement with values ranging from 67.8 - 495.3 x 10-8 m³kg-1 with a mean value of 191.61 x 10-8 m³kg-1 for the Jalingo College of Education (JCOE) data; 520.1 - 1612.8 x 10-8 m³kg-1 with a mean value of 901.34 x 10-8 m³kg-1 for the Jalingo main Market (JMM) and 188.5- 1203.6 x 10-8m³kg-1 with an average value of 574 92 x 10-6 m³kg-1 for the Jalingo Motor Park (JMP). The significant magnetic enhancement indicates high concentration of ferrimagnetic minerals in the soil and hence increased pollution. The magnetic susceptibility of the different land use studied decreased in the order commercial area (market) > motor park > school premises. The results of the percentage frequency dependence susceptibility showed that most of the samples had a mixture of SP and coarse multi domain grains or SP grains

  11. Soil and water pollution studies from a waste site deposit in Bantama, Kumasi, Ghana using magnetic susceptibility measurements

    International Nuclear Information System (INIS)

    The magnetic susceptibility of soil and water samples from around the Uadara barracks waste site deposit in Bantama, a suburb of Kumasi was measured with the aim of investigating the potential threat of pollution to the soil, streams, fish ponds and other water sources at the site around Armed Forces Senior High School campus which shares the same premises with the barracks. The studied soil samples were picked from the near surface (?10 cm depth) along profiles taken from the waste site towards the stream and the ponds. Again, water samples were picked along the stream and from ten (10) ponds aligned along the stream. Laboratory measurements of the magnetic susceptibility were done using the Bartington MS2 metre and the MS2B dual frequency sensor for the soil samples, and the MS2G sensor for the water samples. The soil samples from the site registered an average magnetic susceptibility of 180. 04 x 10-5 SI whereas the water samples recorded an average of -2.3 x 10-6 SI showing a significant increment in comparison with the standard water magnetic susceptibility of -9.04 x 10-6 SI. Thus, not withstand the lithology of the area studied, the presence of heavy metals and other chemical waste materials form the Uadara barracks garbage deposit site were found to greatly pollute the soil and particularly the water bodies around the Armed Forces Senior High School. (au)

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

    Science.gov (United States)

    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.

  13. Frost heave modelling of buried pipelines using non-linear Fourier finite elements

    International Nuclear Information System (INIS)

    Numerical analysis of the response of a three-dimensional soil-pipeline system in a freezing environment using non-linear Fourier finite elements was described as an illustration of the effectiveness of this technique in analyzing plasticity problems. Plastic deformations occur when buried pipeline is under the action of non-uniform frost heave. The three-dimensional frost heave which develops over time including elastoplastic deformations of the soil and pipe are computed. The soil heave profile obtained in the numerical analysis was consistent with experimental findings for similar configurations. 8 refs., 8 figs

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Effects of Topography and Land Use on the Soil Magnetic Susceptibility, Case Study: Madvan Plain, Kohgilouye Province

    Directory of Open Access Journals (Sweden)

    H. R. Owliaie

    2015-03-01

    Full Text Available Topography and land use are among the most important factors affecting the soil formation. Chemical forms of Fe and magnetic susceptibility (? are widely used for the evaluation of soil development. This study was conducted in order to determine the effect of these factors on ?. A toposequence was selected in Madvan Plain, Northern Yasouj. Nine soil profiles (paddy and dryland soils were dug and sampled from diagnostic horizons. Magnetic susceptibility was measured by Bartington Dual Frequency, MS2 Meter at frequencies of 0.46 and 4.6 KHz. Results indicated that less amounts of ?, frequency dependence of ? (?fd% and CBD extractable Fe (Fed (3.1, 2.6 and 2.7 times, respectively, and more quantities of oxalate extractable Fe (Feo and Feo/Fed ratio (5 and 7.2 times, respectively were measured in paddy soils. The highest value of ? was observed in pedons located on plateau and piedmont plains, and the lowest belonged to those located on river terraces with aquic conditions. Compared to paddy soils, ? enhancement at soil surface was greater (17% in dryland soils. A positive correlation existed between ? and some soil characteristics such as Fed, clay content and ?fd%.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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 686.05 MS×10-9 m3/kg, and a minimum and a maximum value of 499.33 and 862.27 MS×10-9 m3/kg respectively. The standard deviation was 85.62 and the coefficient of variation 12.48%. This shows that the spatial variability of soil MS was low. The Global Morans I index was of 0.841, a z-score of 7.741 with a pbottom. Acknowledgments RECARE (Preventing and Remediating Degradation of Soils in Europe Through Land Care, FP7-ENV-2013-TWO STAGE), funded by the European Commission; and for the COST action ES1306 (Connecting European connectivity research). References Boyko, T., Scholger, R., Stanjek, H., MAGPROX team (2004) Topsoil magnetic suseptibility mapping as a tool for pollution monitoring: Repetability of in situ measurments. Journal of Applied Geophysics, 55, 249-259. Dankoub, Z., Ayoubi, S., Khademi, H., Sheng-Gao, L. (2012) Spatial distribution of magnetic properties and selected heavy metals in calcareous soils as affected by land use in the Isfahan Region, Central Iran. Pedosphere, 22, 33-47. Girault, F., Poitou, C., Perrier, F., Koirala, B.P., Bhattarai, M. (2011) Soil characterization using patterns of magnetic susceptibility versus effective radimu concentration. Natural Hazards Earth System Science, 11, 2285-2293. Jeleńska, M., Hasso-Agopsowicz, A., Kopcewicz, B., Sukhorada, A., Tyamina, K., Kądziałko-Hofmokl, M., Matviishina, Z. (2004) Magnetic properties of the profiles of polluted and non-polluted soils. A case study from Ukraine. Geophys. J. Int., 159, 104-116. Morton-Bernea, O., Hernandez, E., Martinez-Pichardo, E., Soler-Arechalde, A.M., Santa Cruz, R.L., Gonzalez-Hernandez, G., Beramendi-Orosco, L., Urritia-Fucugaushi, J. (2009) Mexico city topsoils: Heavy metals vs. magnetic susceptibility. Geoderma, 151, 121-125. Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J. Arcenegui, V., Zavala, L. Modelling the impacts of wildfire on ash thickness in a short-term period, Land Degradation and Development, (In Press), DOI: 10.1002/ldr.2195 Pereira, P., Cerdà, A., Úbeda, X., Mataix-Solera, J., Jordan, A. Burguet, M. (2013) Spatial models for monitoring the spatio-temporal evolution of ashes after fire - a case study of a burnt grassland in Lithuania, Solid Earth, 4, 153-165.

  18. Morning Frost on Martian Surface

    Science.gov (United States)

    2008-01-01

    A thin layer of water frost is visible on the ground around NASA's Phoenix Mars Lander in this image taken by the Surface Stereo Imager at 6 a.m. on Sol 79 (August 14, 2008), the 79th Martian day after landing. The frost begins to disappear shortly after 6 a.m. as the sun rises on the Phoenix landing site. The sun was about 22 degrees above the horizon when the image was taken, enhancing the detail of the polygons, troughs and rocks around the landing site. This view is looking east southeast with the lander's eastern solar panel visible in the bottom lefthand corner of the image. The rock in the foreground is informally named 'Quadlings' and the rock near center is informally called 'Winkies.' This false color image has been enhanced to show color variations. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Evaluation of soil treatments for control of Meloidogyne Arenaria in caladium tubers (Caladium × Hortulanum) and nematode susceptibility of selected cultivars

    Science.gov (United States)

    Field and greenhouse studies were conducted to assess the effectiveness of soil fumigants for control of Meloidogyne arenaria on harvested caladium (Caladium × hortulanum) tubers, to determine the susceptibility of five commonly grown caladium cultivars to M. arenaria, and to evaluate effects of fum...

  20. Ground level air convection produces frost damage patterns in turfgrass.

    Science.gov (United States)

    Ackerson, Bruce J; Beier, Richard A; Martin, Dennis L

    2015-11-01

    Frost injury patterns are commonly observed on the warm-season turfgrass species bermudagrass (Cynodon species Rich.), zoysiagrass (Zoysia species Willd.), and buffalograss [Bouteloua dactyloides (Nutt.) J.T. Columbus] in cool-temperate and subtropical zones. Qualitative observations of these injury patterns are presented and discussed. A model for the formation of such patterns based on thermal instability and convection of air is presented. The characteristic length scale of the observed frost pattern injury requires a temperature profile that decreases with height from the soil to the turfgrass canopy surface followed by an increase in temperature with height above the turfgrass canopy. This is justified by extending the earth temperature theory to include a turf layer with atmosphere above it. Then the theory for a thermally unstable layer beneath a stable region by Ogura and Kondo is adapted to a turf layer to include different parameter values for pure air, as well as for turf, which is treated as a porous medium. The earlier porous medium model of Thompson and Daniels proposed to explain frost injury patterns is modified to give reasonable agreement with observed patterns. PMID:25796203

  1. Frost resistance of building materials

    DEFF Research Database (Denmark)

    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.Calculations of...... critical degrees of saturation are compared with experimentally determined values and results from standardised freeze-thaw tests. Based on these results, the model, its mode of operation and the conditions of the model is analysed and discussed.Appendices and description of supplementary tests are placed...

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

    Directory of Open Access Journals (Sweden)

    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 no difference in the maximum apparent density, although there was significant difference in water content at maximum density. The values altered from 0.249 g g-1, at a maximum compaction point without free organic matter to 0.283 g g-1 with free organic matter.

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

    Scientific Electronic Library Online (English)

    Pedro H., Weirich Neto; André L. T. da, Rosa; Jaime A., Gomes.

    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. Abstract in english For increasing agricultural production, Brazil opted to enlarge the cultivated area, and indiscriminate mechanization was efficient at the first moment, although it altered adversely the soil properties with the passage of time. At the same time, conservation practices, like the direct sowing under [...] the straw (No Tillage) were adopted which is a reality in Southern Brazil. Considering this, the susceptibility for compaction of two classes of soil was evaluated under no tillage system, with and without free organic matter. The Proctor test was used to measure the degree of compaction. The results of a medium texture Cambissol showed there was no difference in susceptibility for compaction. The clay textured Red Latossol, showed no difference in the maximum apparent density, although there was significant difference in water content at maximum density. The values altered from 0.249 g g-1, at a maximum compaction point without free organic matter to 0.283 g g-1 with free organic matter.

  4. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish the......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition of...

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Frost halos from supercooled water droplets

    OpenAIRE

    JUNG Stefan; Tiwari, Manish K.; Poulikakos, Dimos

    2012-01-01

    Water freezing on solid surfaces is ubiquitous in nature. Even though icing/frosting impairs the performance and safety in many processes, its mechanism remains inadequately understood. Changing atmospheric conditions, surface properties, the complexity of icing physics, and the unorthodox behavior of water are the primary factors that make icing and frost formation intriguing and difficult to predict. In addition to its unquestioned scientific and practical importance, unraveling the frostin...

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

    OpenAIRE

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

    2009-01-01

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

  8. Condensation and frost formation in heat exchangers

    International Nuclear Information System (INIS)

    The occurence of condensation and of frost formation are considered for air to heat exchangers with emphasis on how such occurrences would affect the performance of such heat exchangers when they are used in ventilating applications. The formulations which predict performance are developed for parallel, counter flow and cross flow with either formation or condensation, and for condensation the consequences for evaporation of condensate and of the effect of longitudinal conduction in the walls of the exchanger are also considered. For the prediction of the exchanger performance with frost formation there must be specified the growth of the frost layer with time and existing theories for this growth are examined, a new method of calculation of the growth is presented and this is shown to give results for the growth that are in accord with available experimental evidence. This new theory for the growth of a frost layer is used to predict the performance of a parallel flow exchanger under conditions in which frost formation occurs, by successively applying the steady state performance calculation for time increments over which the frost layer build-up is calculated for these time increments. The calculation of counter flow exchanger performance by this method, while feasible, is so time consuming that only the general aspects of the calculation are considered

  9. Frost Growth and Densification in Laminar Flow Over Flat Surfaces

    Science.gov (United States)

    Kandula, Max

    2011-01-01

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

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

    Science.gov (United States)

    Hlodák, Michal; Urík, Martin; Matúš, Peter; Ko?enková, 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. PMID:26247328

  11. Moisture performance analysis of EPS frost insulation

    Energy Technology Data Exchange (ETDEWEB)

    Ojanen, T.; Kokko, E.

    1997-11-01

    A horizontal layer of expanded polystyrene foam (EPS) is widely used as a frost insulation of building foundations in the Nordic countries. The performance properties of the insulation depend strongly on the moisture level of the material. Experimental methods are needed to produce samples for testing the material properties in realistic moisture conditions. The objective was to analyze the moisture loads and the wetting mechanisms of horizontal EPS frost insulation. Typical wetting tests, water immersion and diffusive water vapor absorption tests, were studied and the results were compared with the data from site investigations. Usually these tests give higher moisture contents of EPS than what are detected in drained frost insulation applications. Also the effect of different parameters, like the immersion depth and temperature gradient were studied. Special attention was paid to study the effect of diffusion on the wetting process. Numerical simulation showed that under real working conditions the long period diffusive moisture absorption in EPS frost insulation remained lower than 1% Vol. Moisture performance was determined experimentally as a function of the distance between the insulation and the free water level in the ground. The main moisture loads and the principles for good moisture performance of frost insulation are presented.

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

    OpenAIRE

    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

    2012-01-01

    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-pr...

  13. Future Bloom and Blossom Frost Risk for Malus domestica Considering Climate Model and Impact Model Uncertainties

    OpenAIRE

    Hoffmann, Holger; Rath, Thomas

    2013-01-01

    The future bloom and risk of blossom frosts for Malus domestica were projected using regional climate realizations and phenological (?=?impact) models. As climate impact projections are susceptible to uncertainties of climate and impact models and model concatenation, the significant horizon of the climate impact signal was analyzed by applying 7 impact models, including two new developments, on 13 climate realizations of the IPCC emission scenario A1B. Advancement of phenophases and a decrea...

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

    Science.gov (United States)

    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 Meloidogyne species associated with roots and are good selections for use in ASD for root-knot nematode control. The remainder of crops tested had significant levels of galling, J2, and eggs associated with roots, which varied among the Meloidogyne species tested. PMID:24379486

  15. Visualization of frosting phenomena by using neutron radiography

    International Nuclear Information System (INIS)

    This study focuses on the frost formation on the fin-tube heat exchanger using neutron radiography. The visualization of the frost formation was estimated by the attenuation of the neutron beam through the water. The visualization image of the neutron radiography shows clearly the frost formation phenomena on the fin-tube heat exchanger. The rapid frost formation was observed at the fin and tube edges. Local mass transfer coefficient can be calculated from the differential images of the neutron radiography. (author)

  16. Latest results from FROST at Jefferson Lab

    Directory of Open Access Journals (Sweden)

    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. Heavy Metals in Urban Soils of Xuzhou, China: Spatial Distribution and Correlation to Specific Magnetic Susceptibility

    OpenAIRE

    Xuesong Wang

    2013-01-01

    The investigation of the anthropogenic contamination by heavy metals of soils is very important for environmental planning and monitoring in urban areas. In the present study, surface soils (0-20 cm) samples from 167 sampling sites in Xuzhou (China) were collected in 2010 and analyzed for heavy metals including Zn, Pb, Fe, Mn, Cu, Cd, Sr, Ba Cr, Ni and Mo via inductively coupled plasma/mass spectrometry (ICP-MS). Compared with their levels in natural soils of China, these metals investigated...

  18. Surveying the anthropogenic impact of the Moldau river sediments and nearby soils using magnetic susceptibility.

    Czech Academy of Sciences Publication Activity Database

    Knab, M.; Hoffmann, V.; Petrovský, Eduard; Kapi?ka, Aleš; Jordanova, N.; Appel, E.

    2006-01-01

    Ro?. 49, ?. 4 (2006), s. 527-535. ISSN 0943-0105 Institutional research plan: CEZ:AV0Z3012916 Keywords : Moldau river sediments * magnetic susceptibility * anthropogenic impact Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.610, year: 2006

  19. Correlations between soil magnetic susceptibility and the content of particular elements as a reflection of pollution level, land use and parent rocks

    Science.gov (United States)

    Rachwa?, Marzena; Magiera, Tadeusz; Bens, Oliver; Kardel, Kati

    2015-04-01

    Magnetic susceptibility is a worldwide used measure of (ferri)magnetic minerals occurring in soils, sediments and dusts. In soils, these minerals are of various origin: air-derived particulate pollutions, parent rocks or pedogenesis. Human activity causes different changes in the content of magnetic minerals as well as their spatial and vertical distribution in soil profiles. Magnetic minerals are characterized by an affinity for other elements occurring in the soil, so positive correlations between magnetic susceptibility and particular elements like macrocomponents or heavy metals often occurs. The archival soil samples collected from different soil horizons in the territory of the Free State of Saxony (Germany) were subjected to the magnetic susceptibility measurements using Bartington MS2B. Additionally, samples were chemically analyzed by the S Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences in Potsdam. Values of magnetic susceptibility varied from 9.3 to 1382 ×10-8 m3/kg in organic soil horizon and from 0.1 to 2105 ×10-8 m3/kg in dipper layers. Calculated correlation coefficients between magnetic susceptibility and some elements indicate significant relationships characteristic for different factors influenced soil properties (pollution level, land use and parent rocks). The northern part of Saxony is divided by the Elbe into two parts: east part with loose sedimentary rocks and the west one with more solid loess bedrock enriched by spectrum of elements from the Ore Mountains. Correlations between magnetic susceptibility and Ca, Fe, Mn, and Zn were stated in the eastern, while soil magnetic susceptibility of the western part revealed a correlation with Fe, P, Cd, Cu, Pb, Zn, Mo, U, V, and W. Taking into account influences of industry and urbanization, soil magnetic susceptibility is enhanced in the areas with higher population density comparing with rural sites. In the area of Hoyerswerda and Weisswasser with low magnetic natural background (sand) the load of (ferri)magnetic minerals explained by high magnetic susceptibility values as a result of high pollution level, shows the considerable correlations with Na, Ca, Fe, Mn, Zn, B, Be, V. What is more, the soil magnetic susceptibility, developed on different geological bedrocks, correlates with their natural geochemistry bound in the rock and connected with their ferromagnetic minerals (such magnetite and titanomagnetite present in slate, phyllite, mica schist). In that case the magnetic susceptibility correlates with such elements as: Fe, Mn, Ni, B and V. The soils in the south-eastern Saxony close to the border tri-point of Germany, Poland and the Czech Republic, reveal a correlation of magnetic susceptibility with Cd and As content. It can also be caused by power industry in Zittau, however they are developed on basalts and phonolithes in background that produce also strong magnetic signal of geogenic origin. All the statements made above are usually not so clear, since geogenic processes and anthropogenic influences often overlay in the soil.

  20. Combined Analysis of InSAR Observations and Empirical Models to Assess Soil Erosion Susceptibility

    Science.gov (United States)

    Motagh, M.; Ebrahimzadeh, S.; Haghshenas-Haghighi, M.

    2014-12-01

    Soil erosion is a serious environmental problem in Nozhian Watershed, which is located in Lorestan province of western Iran. Relatively steep slope, heavy precipitation, lack of dense vegetation cover and geological properties of the soil have been attributed as the main factors affecting erosion in the region. The aim of this study is to apply both radar interferometry and empirical methods to evaluate soil erosion pattern in Nozhian and its impact on surface deformation. For the empirical model the following factors were applied to calculate erosion rate: rainfall-runoff erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C) and support practice (P). The R-factor was produced from annual precipitation data, K-factor was developed from soil maps and geological information, LS-factors were calculated from digital elevation model (DEM) and C-factor was created from Landsat-7 ETM images and land cover maps. All factors were then integrated in a GIS environment to derive soil erosion map. For the radar interferometry we utilized 9 PALSAR images acquired by the ALOS satellite between 22 July 2007 and 9 November 2009 and processed them using the Small BAseline Subset (SBAS) technique to obtain time-series maps of surface deformation. The results of InSAR time-series analysis are compared with the information obtained from empirical modeling for quantitative and qualitative assessment of different factors contributing to the erosion. We show that the information obtained by these two independent methods are complemnatry and help us gain a comprehensive and better evaluation of soil loss rate and spatial erosion pattern.

  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

    Science.gov (United States)

    Menzel, Annette; Helm, Raimund; Zang, Christian

    2015-04-01

    The seasonality of woody plants in cold and temperate climates is adapted to the annual course of temperature and photoperiod in order to maximise the length of the active growing season and, at the same time, avoid damages by frost events, especially by late spring frosts. Winter chilling, spring warming and finally photoperiod trigger the timely bud burst of European beech (Fagus sylvatica L.) which as a climax species is quite sensitive to winter frost and also as seedling to late spring frosts. However, due to relatively late and less varying dates of leaf unfolding, damages by late spring frosts should not occur each year. In case of a total loss due to a late frost event, F. sylvatica trees produce a new set of leaves which guarantees survival, but diminishes carbon reserves. With a phenological camera we observed the phenological course of such an extreme event in the Nationalpark Bayerischer Wald in May 2011: Spring leaf unfolding, an almost complete loss of fresh green leaves after the frost event in the night 3rd to 4th May, a subsequent leafless period followed by re-sprouting. We modeled this special leaf development from day 80 to 210, observed as green% from the repeated digital camera pictures, using the Bayesian multiple change point approach recently introduced by Henneken et al. (2013). The results for more than 30 trees predominantly suggested a model with five change points: firstly, start of the season, abrupt ending before the frost event, the loss by the frost event and after a longer period of recovery the second leaf unfolding (St. John's sprout) ending in full leaf maturity. Analyzing the results of these models the following questions were answered (1) how long is the period of recovery till the second green-up? (2) does the temporal course of the second leafing differ from the first one? (3) what are the individual factors influencing damage and recovery? (4) are individuals with early or late bud burst more prone to damage? The five 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. Frost formation under different gaseous atmospheres

    International Nuclear Information System (INIS)

    Rates of water frost growth in a vessel with a cooled horizontal plate were experimentally determined under reduced pressure atmospheres of hydrogen, helium, methane and nitrogen. The mass deposited on the cooled surface under each of the atmospheres was almost in proportion to time. The Sherwood number under the condition of no mist formation, Sh0, in the atmospheres of methane and nitrogen was in good agreement with Catton's equation for natural convection between horizontal parallel plates. Sh0 in a hydrogen atmosphere was unity, which corresponds to control by molecular diffusion in the stagnant gas. The tendency of the decrease in Sh due to mist formation could be evaluated well by multiplying Sh0 by a factor ?CSM. The ?CSM value was calculated based on the critical supersaturation model as a function of the two interface temperatures and the total pressure. Frost growth rates under each atmosphere were in proportion to [(TS1-TW1)t/(1+1/AS1)]0.5. The proportional constant for hydrogen was greater than that for any other tested gas. Agreement and disagreement of the frost effective thermal conductivity with previous models were discussed. (author)

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

    Science.gov (United States)

    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. PMID:22908279

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

    DEFF Research Database (Denmark)

    Farrokhzad, F.; Barari, Amin; Choobbasti, A. J.; Ibsen, Lars Bo

    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...

  5. Isolation and antibiotic susceptibility testing of rapidly-growing mycobacteria from grassland soils.

    Czech Academy of Sciences Publication Activity Database

    Kyselková, Martina; Chro?áková, Alica; N?mec, Jan; Kotrbová, Lucie; Elhottová, Dana

    2013-01-01

    Ro?. 3, ?. 1 (2013), s. 76-80. ISSN 1338-5178 R&D Projects: GA ?R GAP504/10/2077; GA MŠk LC06066; GA MŠk(CZ) EE2.3.30.0032 Grant ostatní: GA JU(CZ) GAJU 04-142/2010/P Institutional support: RVO:60077344 Keywords : mycobakterium isolation and cultivation * grassland soil * antibiotic resistance Subject RIV: EE - Microbiology, Virology

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    M.A.Kausar

    2000-01-01

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

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

    OpenAIRE

    Moshrik R. Hamdi; Mahmoud Abu Alaban; Mohammed Jaber

    2011-01-01

    Radiation and advection frost are common in Jordan as well as other neighboring countries as they face several frost waves each year during the late months of winter. Recently, many frost episodes hit the valley and damaged the crops that were compensated by millions of dollars by the Jordanian Government. This manuscript addresses and characterizes frost, and assesses the role of global warming in impacting frost in terms of its frequency, severity, and total number of frost days per year. A...

  9. Simulated frost effects on cool-season grass carbohydrate levels

    Science.gov (United States)

    Anecdotal observations suggest increased incidences of metabolic problems in horses on pasture after a frost. The speculation is that frost increases the level of nonstructural carbohydrates (NSC) in cool-season grasses, which have been implicated in horse metabolic problems (e.g., laminitis). We co...

  10. Frost Collection Presented to University of the Incarnate Word

    Science.gov (United States)

    Childhood Education, 2004

    2004-01-01

    On April 21, 2004, the Joe L. Frost Children's Play and Play Environments Research Collection was dedicated at the J.E. and L.E. Mabee Library at the University of the Incarnate Word, San Antonio, Texas. This brief article describes the collection and Frost's plans for the future.

  11. Suscetibilidade magnética do solo e estimação da capacidade de suporte à aplicação de vinhaça / Soil magnetic susceptibility for estimating the support capacity to vinasse application

    Scientific Electronic Library Online (English)

    Rafael Gonçalves, Peluco; José, Marques Júnior; Diego Silva, Siqueira; Gener Tadeu, Pereira; Ronny Sobreira, Barbosa; Daniel de Bortoli, Teixeira; Cássia Rita, Adame; Lucas Aguilar, Cortez.

    2013-06-01

    Full Text Available O objetivo deste trabalho foi avaliar a eficiência da suscetibilidade magnética do solo para estimar a capacidade de suporte de áreas à aplicação de vinhaça. Foram coletadas 241 amostras de solo, de uma área de 380 ha, nas quais foram determinados os atributos químicos, os teores de argila e a susce [...] tibilidade magnética do solo. Foram calculadas as doses de vinhaça recomendadas para cada amostra. Os dados foram submetidos à análise estatística descritiva, e foram desenvolvidos modelos de regressão entre a suscetibilidade magnética e os outros atributos avaliados. A análise da dependência espacial dos dados foi feita com uso da geoestatística. Foram construídos mapas de krigagem e variogramas cruzados, para averiguar a correlação espacial entre a suscetibilidade magnética e os atributos estudados. Com base no mapa de recomendação de vinhaça, nas classes de solo e nos mapas de krigagem, foram calculadas as doses médias de vinhaça e as capacidades de suporte médias, ponderadas pela área. A suscetibilidade magnética apresenta correlação espacial linear significativa com as doses de vinhaça recomendadas e com a capacidade de suporte do solo à aplicação desse efluente, e pode ser utilizada como componente da função de pedotransferência, na quantificação indireta da capacidade de suporte. Abstract in english The objective of this work was to evaluate the magnetic susceptibility efficiency for estimating the support capacity of areas for vinasse application. Two hundred forty-one soil samples were collected from a 380-ha area, on which soil chemical properties, clay content, and magnetic susceptibility w [...] ere determined. Vinasse requirement was calculated for each sample. Data were subjected to descriptive statistical analysis, and regression models were developed between magnetic susceptibility and the other evaluated attributes. The analysis of data spatial dependence was performed using geostatistics. Kriging maps and cross variograms were built in order to investigate the spatial correlation between soil magnetic susceptibility and studied attributes. Based on the map of vinasse requirement, on the soil classes, and on the kriging map, calculations were done for average vinasse dose and average soil support capacity, weighted by the area. Magnetic susceptibility has significant linear spatial correlation with recommended vinasse doses and soil support capacity for the application of this effluent, and it can be used as a pedotransfer function for indirect quantification of soil support capacity.

  12. Epidemiologic programs for computers and calculators. Simple algorithms for the representation of deterministic and stochastic versions of the Reed-Frost epidemic model using a programmable calculator.

    Science.gov (United States)

    Franco, E L; Simons, A R

    1986-05-01

    Two programs are described for the emulation of the dynamics of Reed-Frost progressive epidemics in a handheld programmable calculator (HP-41C series). The programs provide a complete record of cases, susceptibles, and immunes at each epidemic period using either the deterministic formulation or the trough analogue of the mechanical model for the stochastic version. Both programs can compute epidemics that include a constant rate of influx or outflux of susceptibles and single or double infectivity time periods. PMID:3962973

  13. Mapeamento do fósforo adsorvido por meio da cor e da suscetibilidade magnética do solo / Mapping adsorbed phosphorus through soil color and magnetic susceptibility

    Scientific Electronic Library Online (English)

    Rafael Gonçalves, Peluco; José, Marques Júnior; Diego Silva, Siqueira; Gener Tadeu, Pereira; Ronny Sobreira, Barbosa; Daniel de Bortoli, Teixeira.

    2015-03-01

    Full Text Available O objetivo deste trabalho foi avaliar a possibilidade de se mapear o fósforo adsorvido por meio da avaliação da cor e da suscetibilidade magnética do solo. O experimento foi realizado em área de cana-de-açúcar com 380 ha, que compreendia quatro tipos de Latossolos, com diferentes texturas e fertilid [...] ades naturais. Foram coletadas 241 amostras de solo, na profundidade de 0,00-0,25 m. O índice de avermelhamento do solo foi calculado a partir dos valores de matiz, valor e croma das amostras, obtidos com espectroscopia de reflectância difusa. Foram ajustados modelos de regressão entre o fósforo adsorvido e a suscetibilidade magnética ou o índice de avermelhamento dos solos. A dependência espacial dos dados foi avaliada por meio de geoestatística. A suscetibilidade magnética correlaciona-se significativamente ao fósforo adsorvido, o que possibilita seu uso como componente de funções de pedotransferência para quantificação indireta do fósforo adsorvido ao solo. O índice de avermelhamento e a suscetibilidade magnética apresentam dependência espacial com o fósforo adsorvido. A suscetibilidade magnética e o índice de avermelhamento dos solos, avaliado pela espectroscopia de reflectância difusa, podem auxiliar no mapeamento e na identificação de áreas com diferentes potenciais de adsorção de fósforo. Abstract in english The objective of this work was to evaluate the possibility of mapping adsorbed phosphorus through soil color and magnetic susceptibility. The experiment was done in a 380-ha sugarcane area, which included four types of Oxisols, with different texture and natural fertility. Two hundred and forty-one [...] soil samples were collected at 0.00-0.25-m depth. The soil redness index was calculated from sample values of hue, value, and chroma, obtained with diffuse reflectance spectroscopy. Regression models were adjusted between adsorbed phosphorus and soil magnetic susceptibility or redness index. Data spatial dependence was evaluated with geostatistics. Magnetic susceptibility is significantly correlated to adsorbed phosphorus, which allows it to be used as a component in pedotransfer functions for indirect quantification of soil adsorbed phosphorus. The redness index and the magnetic susceptibility show spatial dependency with adsorbed phosphorus. Soil magnetic susceptibility and redness index, evaluated with diffuse reflectance spectroscopy, can aid in the mapping and identification of areas with different phosphorus adsorption potential.

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

    Scientific Electronic Library Online (English)

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

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

  15. Characteristics of heat pump system operating with frost formation

    International Nuclear Information System (INIS)

    This paper reports on the performance of heat pump system operating with frost formation that was predicted related to the change of the performance of evaporator due to frosting. The predicted results were compared with the experimental results using a cross-finned tube evaporator. The poor performance of evaporator due to frosting causes the decrease in the heating capacity as the results of the drop of the evaporating temperature and the decrease in the flow rate of refrigerant. The calculated results were in agreement with the experimental results

  16. Nitrogen frost migration on Triton: A historical model

    International Nuclear Information System (INIS)

    The author presents the results of numerical simulations of the seasonal migration of nitrogen frost on Triton, constrained by Voyager observations of atmospheric pressure, temperature, and albedo distribution. Most of the exposed nitrogen is probably seasonal frost, whose migration can produce major variations in atmospheric pressure. For instance, models explored here predict a tenfold pressure drop in the coming decade. The observed albedo patterns can be understood if fresh nitrogen frost is relatively dark butt brightens with increasing insolation in a manner analogous to the Martian southern CO2 cap

  17. Effect of variations in air speed on cross-flow cylinder frosting

    International Nuclear Information System (INIS)

    In this paper the effect of fluctuating air speed on frost growth and heat transfer to a cylinder in cross-flow is discussed. Frost-growth of up to 20 hours is simulated using an experimentally validated finite difference computer model. Graphical results are presented for frost mass, frost depth, frost surface temperature and heat transfer versus time under both steady and fluctuating air speed conditions. In general, it is found that a thinner, more dense frost layer develops under fluctuating air speed conditions giving improved heat transfer. This phenomenon may be explained by the increased frequency of frost surface thaw/freeze cycles when fluctuating air speed conditions prevail

  18. Uremic frost: a harbinger of impending renal failure.

    Science.gov (United States)

    Saardi, Karl M; Schwartz, Robert A

    2016-01-01

    Uremic frost is a striking cutaneous finding seen in patients with severe kidney disease. Familiarity with this condition can be a life-saving signal to initiate urgent dialysis. Uremic frost generally occurs at blood urea nitrogen levels of approximately 200 mg/dl, although it may arise with less severe uremia. Recently confirmed urea transporters in the skin may play a role in the development of uremic frost. Alternatively, damage to the cutaneous microvasculature and pilosebaceous units, as seen in chronic kidney disease, could account for the high levels of urea deposited outside the skin. The treatment of uremic frost is largely aimed at correcting the underlying cause of uremia and the other life-threatening conditions associated with renal failure. PMID:26475684

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Forecast of frost days based on monthly temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, M. T.; Tarquis, A. M.; Corato, M. C.; Saa, A.

    2009-07-01

    Abstract Although frost can cause considerable crop damage, and practices have been developed to mitigate forecasted frost, frost forecasting technologies have not changed for years. This paper reports on a new method based on successive application of two models to forecast the number of monthly frost days for several Community of Madrid (Spain) meteorological stations. The first is an autoregressive integrated moving average (ARIMA) stochastic model that forecasts minimum monthly absolute temperature (t{sub m}in) and average monthly minimum temperature ({mu}{sub t}) following Box and Jenkins methodology. The second model relates monthly temperatures (t{sub m}in, {mu}{sub t}) to the minimum daily temperature distribution during one month. Three ARIMA models were identified. They present the same seasonal behaviour (integrated moving average model) and different non-seasonal part: autoregressive model (Model 1), integrated moving average model (Model 2) and autoregressive and moving average model (Model 3). The results indicate that minimum daily temperature (t{sub d}min) for the meteorological stations studied followed a normal distribution each month with a very similar standard deviation through out the 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 produced the best frost days forecast. This procedure provides a tool for crop managers and crop insurance companies to assess the risk of frost frequency and intensity, so that they can take steps to mitigate frost damage and estimate the damage that frost would cause. (Author) 41 refs.

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

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Ingeman-Nielsen, Thomas; Brock, Niels

    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 pavement initiated by permafrost degradation. One of these white painted areas has been used in the investigations to compare the annual variations of the frost table underneath a normal black asphalt surf...

  2. Delayed Frost Growth on Jumping-Drop Superhydrophobic Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Coupling of THALES and FROST using MPI Method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Woo; Ryu, Seok Hee; Jung, Chan Do; Jung, Jee Hoon; Um, Kil Sup; Lee, Jae Il [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of)

    2013-10-15

    This paper presents the coupling method between THALES and FROST and the simulation results with the coupled code system. In this study, subchannel analysis code THALES and transient fuel performance code FROST were coupled using MPI method as the first stage of the development of the multi-dimensional safety analysis methodology. As a part of the validation, the CEA ejection accident was simulated using the coupled THALES-FROST code and the results were compared with the ShinKori 3 and 4 FSAR. Comparison results revealed that CHASER using MPI method predicts fuel temperatures and heat flux quantitatively well. Thus it was confirmed that the THALES and FROST are properly coupled. In near future, ASTRA, multi-dimensional core neutron kinetics code, will be linked to THALESFROST code for the detailed three-dimensional CEA ejection analysis. The current safety analysis methodology for a CEA ejection accident based on numerous conservative assumptions with the point kinetics model results in quite adverse consequences. Thus, KNF is developing the multi-dimensional safety analysis methodology to enhance the consequences of the CEA ejection accident. For this purpose, three-dimensional core neutron kinetics code ASTRA, subchannel analysis code THALES, and transient fuel performance analysis code FROST are being coupled using message passing interface(MPI). For the first step, THALES and FROST are coupled and tested.

  4. Coupling of THALES and FROST using MPI Method

    International Nuclear Information System (INIS)

    This paper presents the coupling method between THALES and FROST and the simulation results with the coupled code system. In this study, subchannel analysis code THALES and transient fuel performance code FROST were coupled using MPI method as the first stage of the development of the multi-dimensional safety analysis methodology. As a part of the validation, the CEA ejection accident was simulated using the coupled THALES-FROST code and the results were compared with the ShinKori 3 and 4 FSAR. Comparison results revealed that CHASER using MPI method predicts fuel temperatures and heat flux quantitatively well. Thus it was confirmed that the THALES and FROST are properly coupled. In near future, ASTRA, multi-dimensional core neutron kinetics code, will be linked to THALESFROST code for the detailed three-dimensional CEA ejection analysis. The current safety analysis methodology for a CEA ejection accident based on numerous conservative assumptions with the point kinetics model results in quite adverse consequences. Thus, KNF is developing the multi-dimensional safety analysis methodology to enhance the consequences of the CEA ejection accident. For this purpose, three-dimensional core neutron kinetics code ASTRA, subchannel analysis code THALES, and transient fuel performance analysis code FROST are being coupled using message passing interface(MPI). For the first step, THALES and FROST are coupled and tested

  5. Effects of soil moisture and temperature on the susceptibility of welsh onion to ozone. Role of stomata in ozone damage

    Energy Technology Data Exchange (ETDEWEB)

    Asakawa, F.; Imai, T.; Kusaka, S.

    1978-01-01

    Ozone is damaging to crops. The research in this paper showed that there was a relationship between the soil moisture, the soil temperature and the degree of ozone damage. Onion plants were grown in soils of varying temperatures for one month. The plants grown in the soils with the highest moisture content showed the most ozone damage. Ozone damage to the onion plants could be limited by controlling the aperture of the stomata with Ph mercury acetate.

  6. Influencing of covers (peat, snow mosses) on the frost heave by the example of Yamburg (the North of West Siberia)

    Science.gov (United States)

    Ablyazina, D.; Yampolskiy, G.

    2009-04-01

    The frost heave is the one of the widespread and intensively influencing on the objects process. It's also one of the reasons of forming the cryogenic relief. Analytics methods and frost heave map composition, which connected with landscape, cryolithology and geology conditions - the most effective decision of this problem. Now a lot of considerable trends were found out in The Bolshezemelskaya tundra, Yamal and Tazovskiy peninsulas, and they have shown the increase of temperature on 0.02 - 0.06 °C per one year and about 0,7°C per one year in East Siberia. We have studied frost heave in different areas, and calculation of the general frost heave deformation has shown that in West Siberia it's about 40 cm, in East Siberia up to 2m. The Yamburg gas field characterized as the syngenetic type of continuous permafrost area with the sincryogenetic sandshale deposits which are found almost on the all geomorphological levels. This factors are determinates the widespread occurrence of cryolithology factors, especially frost heaving. The frost heave on the Yamburg in the singenetic permafrost happens because of deep seasonal thawing to 1,5m. We have had a set of experiments to determine influencing of peat cover on frost heave. In the laboratory we were modeling conditions of "closed system" with fragmentary freezing. The results have shown that the most influencing cover - peat, while the moss has no affects on the frost heave. The results could be comparing with calculating data which were received for this region, for example in the cold years the peat cover influencing will be lower than in warmer and in the future we could expected the enormous increasing of deformation. Sand deposits which are presents here in itself are not apply to heaving soils, but in case of widespread development of peat and with high dispersion of deposits they are also heaving every season. The maximum ice content was registered in peat or on the contact mineral ground - peat. For the appraisal of experimental data also were done calculations of seasonal frozen layer thickness, in the system sandy clay-clay 2,1m, on the boggy area with peat - 0, 95 m, and with the high thickness of peat on the sandy clay-sand 1m, corresponding to it the frost heaving value will be change, which is confirmed by experiment. These experiments have shown that peat is the most affecting cover on the frost heave and also peat is the most widespread cover in this region. In transition of landscapes including the human intervention most of the natural territorial complexes in tundra interchange to the peats with various thicknesses, therefore it's necessary to pay special attention for interaction peat cover and soils systems and to peat cover influencing for development of cryogenic process.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  9. Forecast of Frost Days Based on Monthly Temperatures

    Science.gov (United States)

    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.

  10. Teor de carbono orgânico e a susceptibilidade à compactação de um Nitossolo e um Argissolo Organic carbon content and susceptibility to compaction of Hapludalf and Hapludox soils

    Directory of Open Access Journals (Sweden)

    João A. Braida

    2010-02-01

    Full Text Available O acúmulo de matéria orgânica pode aumentar a resistência do solo à compactação, diminuindo sua magnitude ou seus efeitos. O objetivo do presente trabalho foi estudar as implicações do acúmulo de matéria orgânica no solo sobre sua susceptibilidade à compactação medida pelo coeficiente de compressão. Buscou-se estabelecer relações entre o teor de carbono orgânico e o coeficiente de compressão do solo. Utilizaram-se amostras de solo coletadas em um Argissolo Vermelho-Amarelo distrófico arênico e de um Nitossolo Vermelho distrófico latossólico, ambos contendo ampla variação do teor de carbono orgânico (CO. As amostras, com umidade equilibrada em quatro tensões de água, foram submetidas ao ensaio de adensamento uniaxial confinado, mediante cargas normais de 12,5, 25, 50, 100, 200, 400, 800 e 1600 kPa e se determinando o coeficiente de compressão plástica; definiram-se, também, o teor de carbono orgânico, a densidade do solo, a porosidade e o grau de saturação com água das amostras. O teor de carbono orgânico afeta o coeficiente de compressão do solo; no entanto, a magnitude e o tipo de efeito são dependentes da textura do solo e de seus efeitos sobre a retenção de água, a coesão e a densidade do solo.Organic matter accumulation can increase soil resistance to compaction, decreasing the compaction magnitude or its effects. The objective of this study was to establish the effect of soil organic matter accumulation on the compressibility index, which corresponds to soil susceptibility to compaction. The study was performed using samples collected from a Hapludalf and a Hapludox soils in southern Brazil, both having a significant variation in soil organic carbon (SOC content. Soil compressibility tests were performed under confined conditions, in a uniaxial apparatus by using normal loads of 12.5, 25, 50, 100, 200, 400, 800 and 1600 kPa, and the compressibility index (Cc was calculated. Soil organic carbon content, bulk density, porosity and water saturation degree were determined too. Results show that soil organic matter content affects the soil compressibility index, however the magnitude and type of effect are dependent upon soil texture and effects associated to soil water retention, cohesion, and bulk density.

  11. Teor de carbono orgânico e a susceptibilidade à compactação de um Nitossolo e um Argissolo / Organic carbon content and susceptibility to compaction of Hapludalf and Hapludox soils

    Scientific Electronic Library Online (English)

    João A., Braida; José M., Reichert; Dalvan J., Reinert; Milton da, Veiga.

    2010-02-01

    Full Text Available O acúmulo de matéria orgânica pode aumentar a resistência do solo à compactação, diminuindo sua magnitude ou seus efeitos. O objetivo do presente trabalho foi estudar as implicações do acúmulo de matéria orgânica no solo sobre sua susceptibilidade à compactação medida pelo coeficiente de compressão. [...] Buscou-se estabelecer relações entre o teor de carbono orgânico e o coeficiente de compressão do solo. Utilizaram-se amostras de solo coletadas em um Argissolo Vermelho-Amarelo distrófico arênico e de um Nitossolo Vermelho distrófico latossólico, ambos contendo ampla variação do teor de carbono orgânico (CO). As amostras, com umidade equilibrada em quatro tensões de água, foram submetidas ao ensaio de adensamento uniaxial confinado, mediante cargas normais de 12,5, 25, 50, 100, 200, 400, 800 e 1600 kPa e se determinando o coeficiente de compressão plástica; definiram-se, também, o teor de carbono orgânico, a densidade do solo, a porosidade e o grau de saturação com água das amostras. O teor de carbono orgânico afeta o coeficiente de compressão do solo; no entanto, a magnitude e o tipo de efeito são dependentes da textura do solo e de seus efeitos sobre a retenção de água, a coesão e a densidade do solo. Abstract in english Organic matter accumulation can increase soil resistance to compaction, decreasing the compaction magnitude or its effects. The objective of this study was to establish the effect of soil organic matter accumulation on the compressibility index, which corresponds to soil susceptibility to compaction [...] . The study was performed using samples collected from a Hapludalf and a Hapludox soils in southern Brazil, both having a significant variation in soil organic carbon (SOC) content. Soil compressibility tests were performed under confined conditions, in a uniaxial apparatus by using normal loads of 12.5, 25, 50, 100, 200, 400, 800 and 1600 kPa, and the compressibility index (Cc) was calculated. Soil organic carbon content, bulk density, porosity and water saturation degree were determined too. Results show that soil organic matter content affects the soil compressibility index, however the magnitude and type of effect are dependent upon soil texture and effects associated to soil water retention, cohesion, and bulk density.

  12. Frost-resistance of red ceramic products

    Directory of Open Access Journals (Sweden)

    Ramires, M. V. V.

    2000-02-01

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

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

  13. Experimental measurements of the effects of frost formation on heat exchanger performance

    International Nuclear Information System (INIS)

    Frost formation on compact heat exchangers can lead to reductions in heat transfer of the order of 50 to 75% and to substantial increases in pressure drop. These effects are dependent upon the spatial pattern of the frost deposition, the growth history of the frost, and the thicknesses of the frost. This paper describes a series of experiments to measure the effects of frost when cold air (260 - 273 K) is passing through the exchanger. It is found that the thermal performance is a function of time and specific humidity levels while the pressure is function only of the frost thickness and surface roughness

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

    Directory of Open Access Journals (Sweden)

    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 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.

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

    Directory of Open Access Journals (Sweden)

    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 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.

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

    Scientific Electronic Library Online (English)

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

    2007-09-15

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

  17. Physical and eco-physiological aspects in forecasting and crop protection of fruit trees from late frost

    International Nuclear Information System (INIS)

    Late frosts represent for fruit production one of the most relevant natural hazards worldwide, considering severity and extent of damage, whose occurrence is constantly increasing, concomitantly to the increase of climate variability. Therefore, impacts on affected farms and local economy are often devastating, but information about how to protect plants from freezing is relatively limited. The research in the field of forecast, risk hazard assessment and protection is directed towards the reduction of the risk level, acting together with new trends in selection of resistant cvs. Crop vulnerability is jointly determined by genetic peculiarities of the various species and cvs, but a determinant role is played by phenology and agronomic practices. The orchard structural features, tree canopy characteristics and tree arrangement in rows are determinant in conditioning energy and radiation exchanges between soil and the surrounding atmosphere, thus on the exchange processes that are responsible of radiation frosts, mainly occurring in Spring, when plant sensibility is at its maximum. The knowledge of local meteorology, together with the weather reports, which can forecast risk situations, should support the acquisition of passive protection systems and to improve the active ones. The correct evaluation of frost risk holds a great importance in fruit orchard programming and in the choice of protection systems and, therefore, the drawing up of risk maps which correlate the topographical characteristics of soil with the tolerance level of the different fruit tree species

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

    Scientific Electronic Library Online (English)

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

    2011-06-01

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

  19. Frost sensor for use in defrost controls for refrigeration

    Science.gov (United States)

    French, Patrick D. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); Butz, James R. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); Veatch, Bradley D. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107); O'Connor, Michael W. (ADA Technologies, Inc. 8100 Shaffer Pkwy., Suite 130, Littleton, CO 80127-4107)

    2002-01-01

    An apparatus and method for measuring the total thermal resistance to heat flow from the air to the evaporative cooler fins of a refrigeration system. The apparatus is a frost sensor that measures the reduction in heat flow due to the added thermal resistance of ice (reduced conduction) as well as the reduction in heat flow due to the blockage of airflow (reduced convection) from excessive ice formation. The sensor triggers a defrost cycle when needed, instead of on a timed interval. The invention is also a method for control of frost in a system that transfers heat from air to a refrigerant along a thermal path. The method involves measuring the thermal conductivity of the thermal path from the air to the refrigerant, recognizing a reduction in thermal conductivity due to the thermal insulation effect of the frost and due to the loss of airflow from excessive ice formation; and controlling the defrosting of the system.

  20. FROST - FREEDOM OPERATIONS SIMULATION TEST VERSION 1.0

    Science.gov (United States)

    Deshpande, G. K.

    1994-01-01

    The Space Station Freedom Information System processes and transmits data between the space station and the station controllers and payload operators on the ground. Components of the system include flight hardware, communications satellites, software and ground facilities. FROST simulates operation of the SSF Information System, tracking every data packet from generation to destination for both uplinks and downlinks. This program collects various statistics concerning the SSF Information System operation and provides reports of these at user-specified intervals. Additionally, FROST has graphical display capability to enhance interpretation of these statistics. FROST models each of the components of the SSF Information System as an object, to which packets are generated, received, processed, transmitted, and/or dumped. The user must provide the information system design with specified parameters and inter-connections among objects. To aid this process, FROST supplies an example SSF Information System for simulation, but this example must be copied before it is changed and used for further simulation. Once specified, system architecture and parameters are put into the input file, named the Test Configuration Definition (TCD) file. Alternative system designs can then be simulated simply by editing the TCD file. Within this file the user can define new objects, alter object parameters, redefine paths, redefine generation rates and windows, and redefine object interconnections. At present, FROST does not model every feature of the SSF Information System, but it is capable of simulating many of the system's important functions. To generate data messages, which can come from any object, FROST defines "windows" to specify when, what kind, and how much of that data is generated. All messages are classified by priority as either (1)emergency (2)quick look (3)telemetry or (4)payload data. These messages are processed by all objects according to priority. That is, all priority 1 (emergency) messages are processed and transmitted before priority 2 messages, and so forth. FROST also allows for specification of "pipeline" or "direct" links. Pipeline links are used to broadcast at constant intervals, while direct links transmit messages only when packets are ready for transmission. FROST allows the user substantial flexibility to customize output for a simulation. Output consists of tables and graphs, as specified in the TCD file, to be generated at the specified interval. These tables may be generated at short intervals during the run to produce snapshots as simulation proceeds, or generated after the run to give a summary of the entire run. FROST is written in SIMSCRIPT II.5 (developed by CACI) for DEC VAX series computers running VMS. FROST was developed on a VAX 8700 and is intended to be run on large VAXes with at least 32Mb of memory. The main memory requirement for FROST is dependent on the number of processors used in the simulation and the event time. The standard distribution medium for this package is a 9-track 1600 BPI DEC VAX BACKUP Format Magnetic Tape. An executable is included on the tape in addition to the source code. FROST was developed in 1990 and is a copyrighted work with all copyright vested in NASA. DEC, VAX and VMS are registered trademarks of Digital Equipment Corporation. IBM PC is a trademark of International Business Machines. SIMSCRIPT II.5 is a trademark of CACI.

  1. Heat and mass transfer in the melting of frost

    CERN Document Server

    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.

  2. Summer frost problems in a locality in Troendelag

    Energy Technology Data Exchange (ETDEWEB)

    Perttu, K.L. (ed.)

    1984-12-01

    Regeneration experiments, including clear cut and shelterwood areas in combination with scarification, were established in 1970-1971. This report is based on results from the meteorological part of these experiments. Measurements from the nearest meteorological network station show that in the period 1951-1983 there were conditions for summer frost every year. Grass minimum temperatures were measured after cold summer nights in a profile on a clear cut belt from the river and to 160 m above. In this terraced terrain the heaviest frost occurred on the leveled sites. Temperature differences up to 7 degrees C were found between the warmest and coldest spots. The shelter effect from 150 trees per ha in combination with scarification raised the minimum temperature up to 6 degrees C. Norway spruce seedlings on clear felled areas have almost no chance to survive the summer frost damage on leveled sites in this region.

  3. Vertical movements of frost mounds in subarctic permafrost regions analyzed using geodetic survey and satellite interferometry

    Science.gov (United States)

    Beck, I.; Ludwig, R.; Bernier, M.; Strozzi, T.; Boike, J.

    2015-08-01

    Permafrost-affected soils cover about 40-45 % of Canada. The environment in such areas, especially those located within the discontinuous permafrost zone, has been impacted more than any other by recorded climatic changes. A number of changes, such as surface subsidence and the degradation of frost mounds due to permafrost thawing, have already been observed at many locations. We surveyed three frost mounds (lithalsas) in the subarctic, close to Umiujaq in northern Quebec, using high-precision differential global positioning system (d-GPS) technology during field visits in 2009, 2010 and 2011, thus obtaining detailed information on their responses to the freezing and thawing that occur during the course of the annual temperature cycle. Seasonal pulsations were detected in the frost mounds, and these responses were shown to vary with their state of degradation and the land cover. The most degraded lithalsa showed a maximum amplitude of vertical movement (either up or down) between winter (freezing) and summer (thawing) of 0.19 ± 0.09 m over the study period, while for the least degraded lithalsa this figure was far greater (1.24 ± 0.47 m). Records from areas with little or no vegetation showed far less average vertical movement over the study period (0.17 ± 0.03 m) than those with prostrate shrubs (0.56 ± 0.02 m), suggesting an influence from the land cover. A differential interferometric synthetic aperture radar (D-InSAR) analysis was also completed over the lithalsas using selected TerraSAR-X images acquired from April to October 2009 and from March to October 2010, with a repeat cycle of 11 days. Interferograms with baselines shorter than 200 m were computed revealing a generally very low interferometric coherence, restricting the quantification of vertical movements of the lithalsas. Vertical surface movements of the order of a few centimeters were recorded in the vicinity of Umiujaq.

  4. Far-infrared spectra of CO2 clathrate hydrate frosts

    Science.gov (United States)

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

    1993-01-01

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

  5. Correlation of Water Frost Porosity in Laminar Flow over Flat Surfaces

    Science.gov (United States)

    Kandula, Max

    2011-01-01

    A dimensionless correlation has been proposed for water frost porosity expressing its dependence on frost surface temperature and Reynolds number for laminar forced flow over a flat surface. The correlation is presented in terms of a dimensionless frost surface temperature scaled with the cold plate temperature, and the freezing temperature. The flow Reynolds number is scaled with reference to the critical Reynolds number for laminar-turbulent transition. The proposed correlation agrees satisfactorily with the simultaneous measurements of frost density and frost surface temperature covering a range of plate temperature, ambient air velocity, humidity, and temperature. It is revealed that the frost porosity depends primarily on the frost surface and the plate temperatures and the flow Reynolds number, and is only weakly dependent on the relative humidity. The results also point out the general character of frost porosity displaying a decrease with an increase in flow Reynolds number.

  6. Heat transfer from a tube immersed in a fluidized bed with frosting

    International Nuclear Information System (INIS)

    Heat-transfer and flow-visualization experiments were performed for a single cooled tube immersed horizontally in a fluidized bed under frosting conditions. Measurements were made from local and average heat-transfer coefficients around the cooled tube surface. Glass beads having nominal diameters of 0.43 mm, 0.89 mm, and 1.6 mm were employed as the bed material. The 30 mm diameter tube was located 100 mm above the distributor. All the results obtained under frosting conditions were for an air temperature of about 5 degrees C and an air relative humidity of about 80 percent. The heat-transfer coefficient with frosting evaluated in this investigation includes the heat-transfer coefficient from the frost surface to the bed and the thermal resistance of the frost layer. Comparisons are made to heat-transfer data without frosting. The heat transfer is found to be larger with frosting than without frosting under the fluidization state

  7. Long term spatial and temporal trends in frost day indices in Kansas, USA

    Science.gov (United States)

    Frost day indices such as number of frost days (nFDs), frost free days (nFFDs), last spring freeze (LSF), first fall freeze (FFF), and growing-season length (GSL), were calculated using daily minimum air temperature (Tmin) values from 23 centennial weather stations spread across Kansas during four t...

  8. Two methods for assessing frost tolerance in flowers of highbush blueberry cultivars

    Science.gov (United States)

    Sensitivity of blueberry flowers to freezing temperatures differs among cultivars and stages of bud development. Also, the frost testing technique and the duration at lethal temperature can have a dramatic effect on bud injury. Artificial frost tests should duplicate the types of spring frosts in ...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Scientific Electronic Library Online (English)

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

    2013-03-01

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

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

    CERN Multimedia

    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.

  12. FROST-INDUCED CHANGES IN SPECTRAL CHARACTERISTICS OF GRAIN SORGHUM.

    Science.gov (United States)

    Visible and near-infrared spectral properties of grain sorghum (Sorghum bicolor) were observed using wideband and hyperspectral radiometers in Arizona. Field measurements that were taken before and after the later-planted, 1998 crop was damaged by frost, displayed temporal dynamics that were correl...

  13. Analysis Of First Fall And Last Spring Advection and Radiation-Advection Frosts In Azerbaijan Provinces

    International Nuclear Information System (INIS)

    Atmospheric Science and Meteorological Research Center (ASMERC)Dates of first fall and last spring frosts on the basis of minimum shelter temperature equal or less than 0°C were determined for 12 synoptic stations for period 1986-2000 in Azerbaijan region. The advection frost was determined based on using of synoptic maps and studying of meteorological elements in different hours. In this work, we found that series of first fall and last spring advection and radiation-advection frosts are random and normally distributed. This study shows that on the average advection frosts start from 6 to 40 days later than radiation-advection frosts in fall and ends 2 to 25 days earlier in spring. Potential growing season that is interval between last spring and first fall advection frost is found to be from 5 to 65 days longer than the growing season defined by the interval from last spring to first fall occurrences of minimum temperature equal or less than 0°C. Crop protection against radiation frosts can bring about too much benefit. To assess whether practical protection of some special crops against radiation frosts is done or not, the number of radiation frosts before first advection frost in fall and after last advection frost in spring, were determined

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

    Directory of Open Access Journals (Sweden)

    Alceu Rodrigues da Silva

    2010-04-01

    Full Text Available Os minerais ferrimagnéticos maghemita (?Fe2O3 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 (?BF 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 ?BF 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 (?FD. 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 ?FD indicaram a presenca de partículas superparamagnéticas (maghemita na maioria dos solos paranaenses.The ferrimagnetic minerals maghemite (?Fe2O3 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 (?BF is the simplest method of identification and quantification of ferrimagnetic minerals in soils. The ?LF is a quick, cheap, non-destructive technique, with satisfactory reproducibility, and can be used as a criterion in pedogenetic studies involving ferrimagnetic minerals. The aim of this paper was to verify the influence of parent rock material on ?LF values of air-dried fine earth of B horizon of soil samples from Paraná. The samples were collected at 45 sites across the entire State to determine the ?LF values and percentage of frequency-dependent magnetic susceptibility (?FD. The values of mass-specific magnetic susceptibility of soils formed from basic eruptive rocks were significantly higher (1,000 to 7,800 x 10-8 m³ kg-1 than of those from sedimentary and metamorphic rocks (lower than 500 x 10-8 m³ kg-1. The data show the strong influence of the parent rock material on the presence of ferrimagnetic minerals. The ?FD values indicate the presence of superparamagnetic particles (maghemite in the majority of the Paraná State soils.

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

    Scientific Electronic Library Online (English)

    Alceu Rodrigues da, Silva; Ivan Granemann de, Souza Junior; Antonio Carlos Saraiva da, Costa.

    2010-04-01

    Full Text Available Os minerais ferrimagnéticos maghemita (?Fe2O3) 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 ess [...] a área corresponde a aproximadamente 50 %. A determinação da suscetibilidade magnética por unidade de massa (?BF) 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 ?BF 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 (?FD). 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 ?FD indicaram a presenca de partículas superparamagnéticas (maghemita) na maioria dos solos paranaenses. Abstract in english The ferrimagnetic minerals maghemite (?Fe2O3) 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 ma [...] gnetic susceptibility (?BF) is the simplest method of identification and quantification of ferrimagnetic minerals in soils. The ?LF is a quick, cheap, non-destructive technique, with satisfactory reproducibility, and can be used as a criterion in pedogenetic studies involving ferrimagnetic minerals. The aim of this paper was to verify the influence of parent rock material on ?LF values of air-dried fine earth of B horizon of soil samples from Paraná. The samples were collected at 45 sites across the entire State to determine the ?LF values and percentage of frequency-dependent magnetic susceptibility (?FD). The values of mass-specific magnetic susceptibility of soils formed from basic eruptive rocks were significantly higher (1,000 to 7,800 x 10-8 m³ kg-1) than of those from sedimentary and metamorphic rocks (lower than 500 x 10-8 m³ kg-1). The data show the strong influence of the parent rock material on the presence of ferrimagnetic minerals. The ?FD values indicate the presence of superparamagnetic particles (maghemite) in the majority of the Paraná State soils.

  16. Frost behavior of a fin surface with temperature variation along heat exchanger fins

    International Nuclear Information System (INIS)

    This paper presents a mathematical model for predicting the frost behavior formed on heat exchanger fins, considering fin heat conduction under frosting condition. The model is composed of air-side, the frost layer, and fin region, and they are coupled to the frost layer. The frost behavior is more accurately predicted with fin heat conduction considered (Case A) than with a constant fin surface temperature assumed (Case B). The results indicate that the frost thickness and heat transfer rate for Case B are over-predicted in most regions of the fin, as compared to those for Case A. Also, for Case A, the maximum frost thickness varies little with the fin length variations, and the extension of the fin length over 30 mm contributes insignificantly to heat transfer

  17. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Controlling condensation and frost growth with chemical micropatterns

    Science.gov (United States)

    Boreyko, Jonathan B.; Hansen, Ryan R.; Murphy, Kevin R.; Nath, Saurabh; Retterer, Scott T.; Collier, C. Patrick

    2016-01-01

    In-plane frost growth on chilled hydrophobic surfaces is an inter-droplet phenomenon, where frozen droplets harvest water from neighboring supercooled liquid droplets to grow ice bridges that propagate across the surface in a chain reaction. To date, no surface has been able to passively prevent the in-plane growth of ice bridges across the population of supercooled condensate. Here, we demonstrate that when the separation between adjacent nucleation sites for supercooled condensate is properly controlled with chemical micropatterns prior to freezing, inter-droplet ice bridging can be slowed and even halted entirely. Since the edge-to-edge separation between adjacent supercooled droplets decreases with growth time, deliberately triggering an early freezing event to minimize the size of nascent condensation was also necessary. These findings reveal that inter-droplet frost growth can be passively suppressed by designing surfaces to spatially control nucleation sites and by temporally controlling the onset of freezing events.

  1. Controlling condensation and frost growth with chemical micropatterns.

    Science.gov (United States)

    Boreyko, Jonathan B; Hansen, Ryan R; Murphy, Kevin R; Nath, Saurabh; Retterer, Scott T; Collier, C Patrick

    2016-01-01

    In-plane frost growth on chilled hydrophobic surfaces is an inter-droplet phenomenon, where frozen droplets harvest water from neighboring supercooled liquid droplets to grow ice bridges that propagate across the surface in a chain reaction. To date, no surface has been able to passively prevent the in-plane growth of ice bridges across the population of supercooled condensate. Here, we demonstrate that when the separation between adjacent nucleation sites for supercooled condensate is properly controlled with chemical micropatterns prior to freezing, inter-droplet ice bridging can be slowed and even halted entirely. Since the edge-to-edge separation between adjacent supercooled droplets decreases with growth time, deliberately triggering an early freezing event to minimize the size of nascent condensation was also necessary. These findings reveal that inter-droplet frost growth can be passively suppressed by designing surfaces to spatially control nucleation sites and by temporally controlling the onset of freezing events. PMID:26796663

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

    Science.gov (United States)

    Bergamaschi, A.; 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-01

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

  4. Modeling the effects of martian surface frost on ice table depth

    Science.gov (United States)

    Williams, K. E.; McKay, Christopher P.; Heldmann, J. L.

    2015-11-01

    Ground ice has been observed in small fresh craters in the vicinity of the Viking 2 lander site (48°N, 134°E). To explain these observations, current models for ground ice invoke levels of atmospheric water of 20 precipitable micrometers - higher than observations. However, surface frost has been observed at the Viking 2 site and surface water frost and snow have been shown to have a stabilizing effect on Antarctic subsurface ice. A snow or frost cover provides a source of humidity that should reduce the water vapor gradient and hence retard the sublimation loss from subsurface ice. We have modeled this effect for the Viking 2 landing site with combined ground ice and surface frost models. Our model is driven by atmospheric output fields from the NASA Ames Mars General Circulation Model (MGCM). Our modeling results show that the inclusion of a thin seasonal frost layer, present for a duration similar to that observed by the Viking Lander 2, produces ice table depths that are significantly shallower than a model that omits surface frost. When a maximum frost albedo of 0.35 was permitted, seasonal frost is present in our model from Ls = 182° to Ls = 16°, resulting in an ice table depth of 64 cm - which is 24 cm shallower than the frost-free scenario. The computed ice table depth is only slightly sensitive to the assumed maximum frost albedo or thickness in the model.

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

    Indian Academy of Sciences (India)

    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.

  6. CRYOLINK: Monitoring of permafrost and seasonal frost in southern Norway

    Science.gov (United States)

    Farbrot, Herman; Hipp, Tobias; Etzelmüller, Bernd; Humlum, Ole; Isaksen, Ketil; Strand Ødegârd, Rune

    2010-05-01

    The modern southern boundary for Scandinavian permafrost is located in the mountains of Southern Norway. Permafrost and seasonal frost are considered key components of the cryosphere, and the climate-permafrost relation has acquired added importance with the increasing awareness and concern of rising air temperatures. The three-year research project CRYOLINK ("Permafrost and seasonal frost in southern Norway") aims at improving knowledge on past and present ground temperatures, seasonal frost, and distribution of mountain permafrost in Southern Norway by addressing the fundamental problem of heat transfer between the atmosphere and the ground surface. Hence, several shallow boreholes have been drilled in August 2008 in three areas (Juvvass, Jetta and Tron) situated along a west-east transect. On most borehole sites air and ground temperatures are measured. Further, vertical arrays of Miniature Temperature Dataloggers (MTDs; Thermochron iBottons®) at fixed heights above the ground surface have been installed to roughly determine the snow depths at the sites, which is also indicated by digital cameras providing daily pictures of snow and weather conditions. In addition individual MTDs have been placed out to measure ground surface temperature at different aspects and snow settings. This presentation will focus on the field set up and give examples of data obtained from the sites.

  7. Frost Induces Respiration and Accelerates Carbon Depletion in Trees

    Science.gov (United States)

    Sperling, Or; Earles, J. Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A.

    2015-01-01

    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. PMID:26629819

  8. Morning Frost in Trench Dug by Phoenix, Sol 113

    Science.gov (United States)

    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 approximately true color. 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.

  9. A new model for predicting performance of fin-and-tube heat exchanger under frost condition

    International Nuclear Information System (INIS)

    Accurate prediction of frost characteristics has crucial influence on designing effective heat exchangers. In this paper, a new CFD (Computational Fluid Dynamics) model has been proposed to predict the frost behaviour. The initial period of frost formation can be predicted and the influence of surface structure can be considered. The numerical simulations have been carried out to investigate the performance of fin-and-tube heat exchanger under frost condition. The results have been validated by comparison of simulations with the data computed by empirical formulas. The transient local frost formation has been obtained. The average frost thickness, heat exchanger coefficient and pressure drop on air side has been analysed as well. In addition, the influence factors have also been discussed, such as fin pitch, relative humidity, air flow rate and evaporating temperature of refrigerant.

  10. Proteins Involved in Distinct Phases of Cold Hardening Process in Frost Resistant Winter Barley (Hordeum vulgare L. cv Luxor

    Directory of Open Access Journals (Sweden)

    Radovan Hynek

    2013-04-01

    Full Text Available Winter barley is an economically important cereal crop grown in higher latitudes and altitudes where low temperatures represent an important environmental constraint limiting crop productivity. In this study changes in proteome of leaves and crowns in a frost tolerant winter barley cv. Luxor in relation to short and long term periods of cold followed by a brief frost treatment were studied in order to disclose proteins responsible for the cold hardening process in distinct plant tissues. The mentioned changes have been monitored using two dimensional difference gel electrophoresis (2D-DIGE with subsequent peptide-mapping protein identification. Regarding approximately 600–700 distinct protein spots detected on 2D gels, there has been found at least a two-fold change after exposure to low temperatures in about 10% of proteins in leaves and 13% of proteins in crowns. Protein and nitrogen metabolic processes have been influenced by low temperature to a similar extent in both tissues while catabolism, carbohydrate metabolism and proteins involved in stress response have been more affected in crowns than in leaves. The range of changes in protein abundance was generally higher in leaves and chloroplast proteins were frequently affected which suggests a priority to protect photosynthetic apparatus. Overall, our data proved existence of slightly different response strategies to low temperature stress in crowns and leaves, i.e., tissues with different biological role. Moreover, there have been found several proteins with large increase in accumulation, e.g., 33 kDa oxygen evolving protein of photosystem II in leaves and “enhanced disease susceptibility 1” in crowns; these proteins might have potential to indicate an enhanced level of frost tolerance in barley.

  11. Late spring and early autumn frosts in connection with global warming.

    Czech Academy of Sciences Publication Activity Database

    St?eštík, Jaroslav

    Nitra : Slovak Agricultural University, 2011 - (Šiška, B.; Hauptvogl, M.; Eliašová, M.), s. 1-5 ISBN 978-80-552-0640-0. [Bioclimate - source and limit of social development. International scientific conference. Topol?ianky (SK), 06.09.2011-09.09.2011] Institutional research plan: CEZ:AV0Z30120515 Keywords : global warming * global temperature * frost-free period * last spring frost * first autumn frost Subject RIV: DE - Earth Magnetism, Geodesy, Geography

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

    Energy Technology Data Exchange (ETDEWEB)

    Fahlen, P.

    1996-12-31

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

  13. 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

    Directory of Open Access Journals (Sweden)

    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 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.

    Palabras claves: Zea mays; calosa; heredabilidad; dialelo; heterosis; suelos ácidos.

  14. Use of Hyperbaric Oxygen in Experimental Frost-Bite

    Directory of Open Access Journals (Sweden)

    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.

  15. Genetic Architecture of Winter Hardiness and Frost Tolerance in Triticale

    OpenAIRE

    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 fros...

  16. Nowcasting in the FROST-2014 Sochi Olympic project

    Science.gov (United States)

    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 nowcasting systems are expected to be used in the project - ABOM, CARDS, INCA, INTW, STEPS, MeteoExpert. FROST-2014 is intended as an 'end-to-end' project. Its products will be used by local forecasters for meteorological support of the Olympics and preceding test sport events. The project is open for new interested participants. Additional information is available at http://frost2014.meteoinfo.ru.

  17. Vertical movements of frost mounds in sub-Arctic permafrost regions analyzed using geodetic survey and satellite interferometry

    Science.gov (United States)

    Beck, I.; Ludwig, R.; Bernier, M.; Strozzi, T.; Boike, J.

    2015-04-01

    Permafrost-affected soils cover about 45% of Canada. The environment in such areas, especially those located within the discontinuous permafrost zone, has been impacted more than any other by recorded climatic changes. A number of changes, such as surface subsidence and the degradation of frost mounds due to permafrost thawing have already been observed at many locations. We surveyed three frost mounds (lithalsas) close to Umiujaq, northern Quebec, sub-Arctic, using a high-precision differential Global Positioning System (d-GPS) during field visits in 2009, 2010 and 2011, thus obtaining detailed information on their responses to the freezing and thawing that occurs during the course of the annual temperature cycle. Seasonal pulsations were detected in the frost mounds and these responses were shown to vary with the state of degradation and the land cover. The most degraded lithalsa showed a maximum amplitude of vertical movement (either up or down) between winter and summer (thawing) of 0.19 ± 0.09 m over the study period, while for the least degraded lithalsa this figure was far greater (1.24 ± 0.47 m). Records from patches with little or no vegetation showed far less average vertical movement over the study period (0.17 ± 0.03 m) than those with prostrate shrubs (0.56 ± 0.02 m), suggesting an influence from the land-cover. A differential Interferometric Synthetic Aperature Radar (D-InSAR) analysis was also completed over the lithalsas using selected TerraSAR-X images acquired from April to October 2009 and from March to October 2010, with a repeat cycle of 11 days. Interferograms with baselines shorter than 200 m were computed revealing a generally very low interferometric coherence, restricting the quantification of vertical movements of the lithalsas. Vertical surface movements in the centimeter range were recorded in the near vicinity of Umiujaq.

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

    Directory of Open Access Journals (Sweden)

    Gheorghe Mladin

    2010-01-01

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

  19. Resilient modulus of freeze-thaw affected granular soils for pavement design and evaluation. Part 3: Laboratory tests on soils from Albany County Airport

    Science.gov (United States)

    Cole, D. M.; Bentley, D. L.; Durell, G. D.; Johnson, T. C.

    1987-02-01

    This is the third in a series of four reports on the laboratory and field testing of a number of road and airfield subgrades, covering the laboratory repeated-load triaxial testing of five soils in the frozen and thawed states and analysis of the resulting resilient modulus measurements. The laboratory testing procedures allow simulation of the gradual increase in stiffness found in frost-susceptible soils after thawing. The resilient modulus is expressed in a nonlinear model in terms of the applied stresses, the soil moisture tension level (for unfrozen soil), the unfrozen water content (for frozen soil) and the dry density. The resilient modulus is about 10 GPa for the frozen material at temperatures in the range of -5 to -8 C. The decrease in modulus with increasing temperature was well-modeled in terms of the unfrozen water content. Upon thaw, the modulus dropped to about 100 MPa and generally increased with increasing confining stress and decreased with increasing principal stress ratio. The modulus also increased with the soil moisture tension level. The resilient Poisson's ratio did not appear to be a systematic function of any of the test variables.

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

    Science.gov (United States)

    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...

  1. Infra-red thermography for detecting frost pockets on snow-covered clear-fellings

    International Nuclear Information System (INIS)

    The purpose of the investigation was to find out if IR-thermography from aircraft could be a useful method for registration and studies of regional variation of frost exposition within an area and of distribution of frost risks within individual felling areas. The technique, which was successful, has up till now not been utilized in Sweden for such studies in woodland

  2. Heat and mass transfer in frost and ice, packed beds, and environmental discharges

    International Nuclear Information System (INIS)

    This volume covers issues related to heat and mass transfer in frost and ice packed beds, and environmental discharges. Topics include: measurements of the effects of frost on heat exchanger performance, a study of steam zone behavior in porous media, heat and mass transfer by natural convection, and a review of selected programs for atmospheric dispersion

  3. Frost as a first wall for the ICF laboratory microfusion facility

    International Nuclear Information System (INIS)

    The authors introduce the concept of using frost as the first wall of the ICF Laboratory Microfusion Facility being designed to produce 200-1000 MJ of thermonuclear yield. They present one design incorporating 2cm of frost deposited at 0.1 g/cm/sup 3/ on an LN-cooled fiber-reinforced polymer substrate. They calculate that such a frost layer will protect the substrate from ablation by target x rays and debris, and from shock-induced spallation. Postshot washdown with water should permit low-activation operation, and should preserve the original wall properties. The authors expect the impact of the frost on laser optics to be minimal, and expect the preshot lifetime of thermally unprotected cryogenic targets to be extended by operating the wall at 100-150 K. Moreover, they believe that such a frost first wall involves little technical risk, and will be inexpensive to construct and operate

  4. Soil

    International Nuclear Information System (INIS)

    Environmental soil surveys in each province of Austria have been performed, soils of about 5,000 sites were described and analyzed for nutrients and pollutants, the majority of these data are recorded in the soil information system of Austria (BORIS) soil database, http://www.ubavie.gv.at/umweltsituation/boden/boris), which also contains a soil map of Austria, data from 30 specific investigations mainly in areas with industry and results from the Austria - wide cesium investigation. With respect to the environmental state of soils a short discussion is given, including two geographical charts, one showing which sites have soil data (2001) and the other the cadmium distribution in top soils according land use (forest, grassland, arable land, others). Information related to the soil erosion, Corine land cover (Europe-wide land cover database), evaluation of pollutants in soils (reference values of As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Se, Pb, Tl, Va, Zn, AOX, PAH, PCB, PCDD/pcdf, dioxin), and relevant Austrian and European standards and regulations is provided. Figs. 2, Tables 4. (nevyjel)

  5. 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

    Scientific Electronic Library Online (English)

    Alba Lucía, Arcos; Luis Alberto, Narro; Fredy, Salazar; Creuci, Caetano.

    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). Abstract in english 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 con [...] trolled 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).

  6. Soils

    Science.gov (United States)

    Schaetzl, Randall J.; Anderson, Sharon

    2005-06-01

    This comprehensive work on all aspects of soils includes introductory chapters on soil morphology, physics, mineralogy and organisms in anticipation of the more advanced analysis of the subject that follows. Replete with hundreds of high-quality figures and a large glossary, its global perspective makes it an invaluable text for anyone studying soils, landforms and landscape change in middle to upper-level undergraduate and graduate courses.

  7. Soils

    International Nuclear Information System (INIS)

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

  8. Evaluation and improvement of frost durability of clay bricks

    Science.gov (United States)

    Koroth, Surej Raghavan

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

  9. CFD analysis of tube-fin 'no-frost' evaporators

    Scientific Electronic Library Online (English)

    Jader R, Barbosa, Jr; Christian J. L, Hermes; Cláudio, Melo.

    2010-12-01

    Full Text Available The purpose of this paper is to assess some aspects of the design of evaporators for household refrigeration appliances using Computational Fluid Dynamics (CFD). The evaporators under study are tube-fin 'no-frost' heat exchangers with forced convection on the air-side and a staggered tube configurat [...] ion. The calculation methodology was verified against experimental data for the heat transfer rate, thermal conductance and pressure drop obtained for two evaporators with different geometries. The average errors of the heat transfer rate, thermal conductance and pressure drop were 10%, 3% and 11%, respectively. The CFD model was then used to assess the influence of geometric parameters such as the presence and position of the electrical heater coil relative to the tubes, the fin configuration and the width of the by-pass clearance between the outer edge of the fins and the tube bank for conditions typical of the design of household refrigeration appliances

  10. Helicity Asymmetry in gamma p -> pi+ n with FROST

    International Nuclear Information System (INIS)

    The main objective of the FROST experiment at Jefferson Lab is the study of baryon resonances. The polarization observable E for the reaction gamma p to pi+n has been measured as part of this program. A circularly polarized tagged photon beam with energies from 0.35 to 2.35 GeV was incident on a longitudinally polarized frozen-spin butanol target. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization data agree fairly well with present SAID and MAID partial-wave analyses at low photon energies. In most of the covered energy range, however, significant deviations are observed. These discrepancies underline the crucial importance of polarization observables to further constrain these analyses.

  11. Helicity asymmetry E in ?p-->?+n with FROST

    Science.gov (United States)

    Strauch, Steffen; CLAS Collaboration

    2012-04-01

    The main objective of the FROST experiment at Jefferson Lab is the study of baryon resonances. The polarization observable E for the reaction ?p??+n has been measured as part of this program. A circularly polarized tagged photon beam with energies from 0.35 to 2.35 GeV was incident on a longitudinally polarized frozen-spin butanol target. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization data agree fairly well with present SAID and MAID partial-wave analyses at low photon energies. In most of the covered energy range, however, significant deviations are observed. These discrepancies underline the crucial importance of polarization observables to further constrain these analyses.

  12. Modeling the airside dynamic behavior of a heat exchanger under frosting conditions

    International Nuclear Information System (INIS)

    A general distributed model with a non-steady-state heat exchanger model coupled with a frost model was developed to study the dynamic behavior of an airside heat exchanger in an air-to-water heat pump heater/chiller unit. The effects of water vapor diffusion and uneven fin temperature distribution were considered. The model was found to agree well with reported experimental results. Compared with the routine model, the present model has higher precision of frost layer thickness especially on the fin surface. Results include the propagation of frost formation along the tube and its effect on the dynamic characteristics of refrigerant, air, and tube sides. According to the results, the temperature difference between air and tube surface temperature was proposed to be the main driving force of frosting. Tube surface temperature is the most important factor affecting frosting when there is little variation in air humidity. Frost at the fin base was found to be thicker than that at the fin tip due to the fact that the frost layer grows faster with lower tube surface temperature

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

    DEFF Research Database (Denmark)

    Barber, D.; Ehn, J.; Pucko, M.; Rysgaard, Søren; Deming, J. W.; Bowman, J.S.; Papakyriakou, T. N.; Galley, R.J.; Søgaard, DH

    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...... primarily originated from the surface brine skim. Ikaite crystals were observed to form within an hour in both frost flowers and the thin pond ice. Average ikaite concentrations were 1013?µmol?kg?1 in frost flowers and 1061?µmol?kg?1 in the surface slush layer. Chamber flux measurements confirmed an efflux...

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

    DEFF Research Database (Denmark)

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

    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 calm wind conditions. The sea ice surface temperature at the time of frost flower initiation was 10-13°C warmer than the air temperature. Frost flowers grew on nodules raised above the mean surface height by 5 mm, which were 4-6°C colder than the bare, brine-wetted, highly saline sea ice surface that provided the necessary moisture. The cold nodules created potential water vapour super saturation zones abovethem with respect to air over the brine skim. Frost flowers formed and grew overnight in the absence of shortwave radiation, while the net long wave radiation was negative and dominated the net all-wave radiation balance at the surface. The observed crystal habits of the frost flowers were long needles, betraying their origin from the vapour phase at temperatures between -20°C and -30°C. After a night of growth, frost flowers decayed associated with increased solar radiation, a net surface radiation balance of 0 W m-2, increased air and surface temperatures, increased wind speed, and decreased relative humidity. We hypothesize that these conditions increased vertical mixing, which eroded near-surface water vapour saturation and initiated sublimation. The frost flowers were finally rapidly destroyed by snowfall.

  15. Frost flowers as a source of fractionated sea salt aerosol in the polar regions

    OpenAIRE

    Rankin, A. M.; Auld, V.; Wolff, E.W.

    2000-01-01

    Frost flowers collected from the surface of new sea ice near the Brunt Ice Shelf, Antarctica, show depletion in sulphate and sodium relative to other sea water ions. This is consistent with loss of mirabilite (Na2SO4) during formation of the brine from which the frost flowers grow. Aerosol generated from frost flowers would have higher sodium:sulphate ratios than aerosol generated from sea water. This would explain low values of non-sea-salt sulphate encountered in winter aerosol, and winter ...

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

    Directory of Open Access Journals (Sweden)

    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. Results show that the factors related with the susceptibility to interrill erosion are associated not just to the characteristics and properties that confer cohesivity to soil, but also to those factors that affect runoff hydraulics and therefore the sediment transport phase as well.

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

    Scientific Electronic Library Online (English)

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

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

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

    Index Scriptorium Estoniae

    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

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

    DEFF Research Database (Denmark)

    Galley, R.J.; Else, B.G.T.; Geilfus, Nicolas-Xavier; Hare, A.A.; Babb, D.; Papakyriakou, T.N.; Barber, D.G.; Rysgaard, Søren

    2015-01-01

    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...... provided the necessary moisture. The cold nodules created potential water vapour super saturation zones above them with respect to air over the brine skim. Frost flowers formed and grew overnight in the absence of shortwave radiation, while the net long wave radiation was negative and dominated the net all...... balance of 0 W m-2, increased air and surface temperatures, increased wind speed, and decreased relative humidity. We hypothesize that these conditions increased vertical mixing, which eroded near-surface water vapour saturation and initiated sublimation. The frost flowers were finally rapidly destroyed...

  20. Development of sour cherry generative organs and formation of spring frost resistance

    OpenAIRE

    Stepulaitien?, Inga

    2013-01-01

    Sour cherry (Prunus cerasus L. (sin. Cerasus vulgaris Mill., Prunus vulgaris Schur)) is widely grown stonefruit tree in Lithuania. Productivity of sour cherry orchard depends on many tightly related factors. It's know that negative temperature and spring frosts are important factors determinating plant productivity. These factors must be considered in plant breeding. Risks of extreme temperatures, humidity deficiency and spring frosts increases due to climate change. Plant reaction to ...

  1. Moisture design with regard to deterioration of materials and structures - with special reference to frost destruction

    OpenAIRE

    Fagerlund, Göran

    2006-01-01

    The work is composed of three parts: - (1) An overview of the concept moisture deign with regard to service life. (this report) - (2) A practical application of service life analysis applied to frost damage, based on materials testing. (this report) - (3) A theroretical analysis of methods for service life design of concrete and concrete structures exposed to internal frost damage (Report TVBM-04/3119).

  2. Frosted Branch Angiitis as Ocular Manifestation of Behçet's Disease: Unusual Case Report and Literature Review

    OpenAIRE

    Kwon, Soon Jae; Park, Dong Ho; Shin, Jae Pil

    2013-01-01

    We report an unusual case of unilateral frosted branch angiitis associated with Behçet's disease, including a review of previously reported cases. A 39-year-old male with history of recurrent oral and genital ulcers presented with visual loss in his left eye. Fundus findings demonstrated occlusive retinal vasculitis resembling acute frosted branch angiitis. Laboratory examinations including viral markers revealed no abnormal findings except positive HLA-B51. The patient was treated with syste...

  3. Metal stress consequences on frost hardiness of plants at northern high latitudes: a review and hypothesis

    International Nuclear Information System (INIS)

    This paper reviews the potential of trace/heavy metal-induced stress to reduce plant frost hardiness at northern high latitudes. The scientific questions are first outlined prior to a brief summary of heavy metal tolerance. The concepts of plant capacity and survival adaptation were used to formulate a hypothesis, according to which heavy metal stress may reduce plant frost hardiness for the following reasons: (1) Heavy metals change membrane properties through impaired resource acquisition and subsequent diminution of the cryoprotectant pool. (2) Heavy metals change membrane properties directly through oxidative stress, i.e. an increase of active oxygen species. (3) The involved co-stress may further increase oxidative stress. (4) The risk of frost injury increases due to membrane alterations. An opposite perspective was also discussed: could metal stress result in enhanced plant frost hardiness? This phenomenon could be based on the metabolism (i.e. glutathione, polyamines, proline, heat shock proteins) underlying a possible general adaptation syndrome of stress (GAS). As a result of the review it was suggested that metal-induced stress seems to reduce rather than increase plant frost hardiness. - Metal stress may reduce plant frost hardiness

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

    International Nuclear Information System (INIS)

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

  5. Reconstructing patterns of temperature, phenology, and frost damage over 124 years: spring damage risk is increasing.

    Science.gov (United States)

    Augspurger, Carol K

    2013-01-01

    Climate change, with both warmer spring temperatures and greater temperature fluctuations, has altered phenologies, possibly leading to greater risk of spring frost damage to temperate deciduous woody plants. Phenological observations of 20 woody species from 1993 to 2012 in Trelease Woods, Champaign County, Illinois, USA, were used to identify years with frost damage to vegetative and reproductive phases. Local temperature records were used in combination with the phenological observations to determine what combinations of the two were associated with damage. Finally, a long-term temperature record (1889-1992) was evaluated to determine if the frequency of frost damage has risen in recent decades. Frost forest edge. The degree of damage varied with species, life stage, tissue (vegetative or reproductive), and phenological phase. Common features associated with the occurrence of damage to interior plants were (1) a period of unusual warm temperatures in March, followed by (2) a frost event in April with a minimum temperature forest, the combination of warming trends and temperature variability (extremes) associated with climate change is having ecologically important effects, making previously rare frost damage events more common. PMID:23600239

  6. Decreased frost hardiness of Vaccinium vitis-idaea in reponse to UV-A radiation.

    Science.gov (United States)

    Taulavuori, Kari; Keränen, Johanna; Suokanerva, Hanne; Lakkala, Kaisa; Huttunen, Satu; Laine, Kari; Taulavuori, Erja

    2012-08-01

    The aim of this study was to investigate plant frost hardiness responses to ultraviolet (UV) radiation, since the few results reported are largely contradictory. It was hypothesized that functional adaptation of life forms could explain these contradictions. Dwarf shrubs and tree seedlings, representing both evergreen and deciduous forms, were tested (Vaccinium vitis-idaea, Vaccinium myrtillus, Pinus sylvestris, Betula pubescens and its red form f. rubra). The research was performed in Sodankylä, Northern Finland (67°N), with enhanced UV-B- and UV-A-radiation treatments between 2002 and 2009. Plant frost hardiness was determined using the freeze-induced electrolyte leakage method in early autumn, during the onset of the frost hardening process. Additional physiological variables (malondialdehyde, glutathione, total phenols, C and N contents) were analyzed in V. vitis-idaea to explain the possible responses. These variables did not respond significantly to UV-radiation treatments, but explained the frost hardiness well (r² = 0.678). The main finding was that frost hardiness decreased in the evergreen shrub V. vitis-idaea, particularly with enhanced UV-A radiation. No significant responses were observed with the other plants. Therefore, this study does not support the idea that enhanced UV radiation could increase plant frost hardiness. PMID:22182287

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

    Science.gov (United States)

    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 ?-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. PMID:23025512

  8. Polarization Observables in the --> --> -->?+?- p Reaction from FROST

    Science.gov (United States)

    Strauch, Steffen; Jiang, Hao; Mao, Yuqing; Net, Aneta; CLAS Collaboration

    2013-10-01

    Double-pion photoproduction is an important tool in the study of baryon resonances. It dominates the total photoabsorption cross section above the second resonance region and allows the study of resonance decay properties. The --> --> -->?+?p reaction has been measured in Hall B at Jefferson Lab with linearly and circularly polarized tagged photon beams incident on longitudinally and transversely polarized protons. The experiment covered center-of-mass energies between 1.4 GeV and 2.3 GeV. The target was a FROzen Spin Target (FROST) and the final-state particles were detected by the CEBAF Large Acceptance Spectrometer (CLAS). Linear combinations of polarized yields have been used for the extraction of the single-, Pz, I?, and double- polarization observables, Px, y ?, Pzc , s . Most of these observables were extracted for the first time. Calculations of an effective Lagrangian model have been compared with the preliminary results and resemble some features of the data. The data will constrain model calculations and test our understanding of nucleon structure by establishing reaction amplitudes. The data will thus improve our knowledge of photocouplings, hadronic resonance decays, and possibly help to identify new baryon resonances. Supported in parts by the U.S. National Science Foundation: NSF PHY-1205782.

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Willians J Reyes R

    2010-04-01

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

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

    Scientific Electronic Library Online (English)

    Willians J, Reyes R.

    2010-04-01

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

  12. TuBaFrost: European virtual tumor tissue banking.

    Science.gov (United States)

    Riegman, P H J; Oomen, M H A; Dinjens, W N M; Oosterhuis, J W; Lam, K H; Spatz, A; Ratcliffe, C; Knox, K; Mager, R; Kerr, D; Pezzella, F; Van Damme, B; Van De Vijver, M; Van Boven, H; Morente, M M; Alonso, S; Kerjaschki, D; Pammer, J; López-Guerrero, J A; Llombart-Bosch, A; Carbone, A; Gloghini, A; Teodorovic, I; Isabelle, M; Passioukov, A; Lejeune, S; Therasse, P; Van Veen, E B

    2006-01-01

    TuBaFrost is a consortium responsible for the task to create a virtual European human frozen tumor tissue bank, composed of high quality frozen tumor tissue collections with corresponding accurate diagnosis stored in European cancer centers and universities, searchable on the Internet, providing rules for access and use and a code of conduct to comply with the various legal and ethical regulations in European countries. Such infrastructure would enlarge tissue availability and accessibility in large amounts of specified or even rare tumor samples. Design of an infrastructure for European residual tissue banking with the described characteristics, clear focus points emerge that can be broken down in dedicated subjects: (1) standardization and quality assurance (QA) to avoid inter-institute quality variation; (2) law and ethics enabling exchange of tissue samples possible between institutes in the different European countries, where law and ethics are characterized by a strong variability; (3) rules for access, with sufficient incentives for collectors; (4) central database application containing innovations on search and selection procedures; (5) support when needed with histology images; and (6) Internet access to search and upload, with in addition a solid website giving proper information on the procedures, intentions and activities not only to the scientific community, but also to the general public. One consortium decision, part of the incentives for collectors, had major impact on the infrastructure; custodianship over the tissues as well as the tissues stay with the collector institute. Resulting in specimens that are not given to an organization, taking decisions on participation of requests, but instead the local collected tissues stay very easy to access by the collector and allows autonomous negotiation between collector and requestor on cooperation, coauthorship in publication or compensation in costs. Thereby, improving availability of large amounts of high quality samples of a highly specified or rare tumor types and contact opportunities for cooperation with other institutes. PMID:17163156

  13. Structural Analysis of the Redesigned Ice/Frost Ramp Bracket

    Science.gov (United States)

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

    2007-01-01

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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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 that if fluxes are high enough, i.e. greater than 5–10 ?g N m?2 h?1, the EC method is a good alternative to measure N2O and CO2 fluxes at ecosystem scale, thereby minimizing problems with chamber enclosures and spatial representativeness of the measurements.

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

    Directory of Open Access Journals (Sweden)

    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 Beh?et disease, Frosted branch angiitis, and neuroretinitis is not reported in literature. This uncommon combination reflects the varied systemic and ocular manifestations in Beh?et 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.

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    2013-01-01

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

  2. Frosted branch angiitis as ocular manifestation of Behçet's disease: unusual case report and literature review.

    Science.gov (United States)

    Kwon, Soon Jae; Park, Dong Ho; Shin, Jae Pil

    2013-12-01

    We report an unusual case of unilateral frosted branch angiitis associated with Behçet's disease, including a review of previously reported cases. A 39-year-old male with history of recurrent oral and genital ulcers presented with visual loss in his left eye. Fundus findings demonstrated occlusive retinal vasculitis resembling acute frosted branch angiitis. Laboratory examinations including viral markers revealed no abnormal findings except positive HLA-B51. The patient was treated with systemic steroid and cyclosporine. Six months after presentation, new oral ulcers and pseudofolliculitis appeared, and he was diagnosed with Behçet's disease following rheumatology consultation. During follow-up, there was no change in visual acuity of hand movement, and disc neovascularization developed even after complete panretinal photocoagulation. Ocular manifestations of Behçet's disease can present as unilateral frosted branch angiitis, and may consecutively involve in both eyes. Early immunosuppressive treatment is recommended. PMID:24311935

  3. Five second helium neutral beam injection using argon-frost cryopumping techniques

    International Nuclear Information System (INIS)

    High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. A nano-frost array technique to prepare nanoporous PVDF membranes

    Science.gov (United States)

    Lee, Min Kyung; Lee, Jonghwi

    2014-07-01

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

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

    OpenAIRE

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

    2009-01-01

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

  8. Frost hardiness of mycorrhizal and non-mycorrhizal Scots pine under two fertilization treatments.

    Science.gov (United States)

    Korhonen, Anna; Lehto, Tarja; Repo, Tapani

    2015-07-01

    Survival and functioning of mycorrhizal associations at low temperatures are not known well. In an earlier study, ectomycorrhizas did not affect the frost hardiness of Scots pine (Pinus sylvestris L.) roots, but here we studied whether differential nutrient availability would change the result and additionally, alter frost hardiness aboveground. The aim in this experiment was to compare the frost hardiness of roots and needles of mycorrhizal (Hebeloma sp.) and non-mycorrhizal Scots pine seedlings raised using two fertilization treatments and two cold-hardening regimes. The fertilization treatments were low (LF) and high (HF) application of a complete nutrient solution. Three hundred mycorrhizal and non-mycorrhizal seedlings were cultivated in growth chambers in four blocks for 16 weeks. For the first 9 weeks, the seedlings grew in long-day and high-temperature (LDHT) with low fertilization and then they were raised for 3 weeks in LDHT with either low or high fertilization. After this, half of the plants in each treatment combination remained in LDHT, and half were transferred to short-day and low-temperature (SDLT) conditions to cold acclimatize. The frost hardiness of the roots and needles was assessed using controlled freezing tests followed by electrolyte leakage tests (REL). Mycorrhizal roots were slightly more frost hardy than non-mycorrhizal roots, but only in the growing-season conditions (LDHT) in low-nutrient treatment. In LDHT and LF, the frost hardiness of the non-mycorrhizal roots was about -9 °C, and that of the non-mycorrhizal HF roots and the mycorrhizal roots in both fertilization levels was about -11 °C. However, no difference was found in the roots within the SDLT regime, and in needles, there was no difference between mycorrhizal and fertilization treatments. The frost hardiness of needles increased by SDLT treatment, being -8.5 and -14.1 °C in LDHT and SDLT, respectively. The dry mass of roots, stems, and needles was lower in LF than in HF and lower in SDLT than in LDHT. Mycorrhizal treatment did not affect the dry mass or its allocation. Although the mycorrhizal roots were slightly more frost hardy in the growing-season conditions, this is not likely to have significance in the field. PMID:25404213

  9. Near infrared reflectance spectra and analysis of H2S frost as a function of temperature

    International Nuclear Information System (INIS)

    The reflection spectra of H2S frost in the near infrared region (1.6--4 ?m), as a function of temperature to 62 degreeK, were measured. Analyses of these spectra were made, and assignments for the most intense combinations attempted. Dramatic changes in spectra are observed from 62--143 degreeK, connected with a phase transition between a tetragonal, low-temperature phase and a cubic, high-temperature phase, occurring at 125 +- 5 degreeK. The data present evidence for only two phases being involved for H2S frost

  10. Evaluations on power ramp data of PWR fuels by FROST and THERMOST codes

    International Nuclear Information System (INIS)

    An evaluation is presented of power ramp data of Mitsubishi's PWR fuel rods tested in R-2, Studsvik, which was analysed by FROST and THERMOST codes. The analyses give good predictions for measured diameter changes and on-power rod elongations. The work indicates that FROST is capable of analysing both radial and axial pellet-cladding mechanism interaction (PCMI) appropriately, and that predicted states of PCMI (i.e. stress and strain which cannot be measured directly) are considered to be reliable. The ramp data used in the present analyses were obtained in two joint programmes with five Japanese PWR utilities (KEPCO, KYEPCO, SEPCO, HEPCO, and JAPCO). (UK)

  11. Frosted branch angiitis caused by Varicella Zoster virus in an immunocompetent patient

    Directory of Open Access Journals (Sweden)

    Mahshid Talebi-Taher

    2015-10-01

    Full Text Available Introduction: Frosted branch angiitis(FBA is a panuveitis with sheating of all retinal vesssels.Case presentation: Herein we report an immunocompetent person who presented with fever, headache, atypical rash, and hazy vision. Ophthalmoscopy of both eyes revealed perivascular sheathing with frosted branch angiitis pattern in veins, patchy retinal hemorrhages. Aqueous PCR analysis turned positive for VZV.Discussion: This case illustrates that VZV should be considered in the differential diagnosis of retinal perivasculitis. Since a rapid and accurate diagnosis is crucial for prompt administration of antiviral therapy, PCR-based analysis of aqueous humor is a valuable tool for detecting viruses.

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

    Scientific Electronic Library Online (English)

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

    2013-12-01

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

  13. Study of frost growth on heat exchangers used as outdoor coils in air source heat pump systems

    Science.gov (United States)

    K P, Sankaranarayanan

    2011-12-01

    Scope and method of study. During winter heating operation, the outdoor coil of a heat pump acts as an evaporator and when the ambient temperature is near freezing, the moisture in the atmospheric air freezes on the coil surface. The frost growth affects the air flow and also adds resistance to heat transfer thus reducing the capacity and the efficiency of the heat pump. An experimental facility is designed and built to test a small scale heat exchanger working in frosting conditions. Tests are carried out using small scale fin-tube and microchannel heat exchanger over a range of glycol inlet temperatures, air velocities and ambient air RH. A semi-empirical frost model based on a scaling approach is developed and applied to both fin-tube heat and microchannel heat exchangers. The model is developed to handle non-uniformities in both refrigerant and air side. The frost model is integrated with a segment-by-segment heat exchanger calculation algorithm and is validated against experimental data. Frost growth model is also incorporated in a quasi-steady state system simulation algorithm. Findings and conclusions. From the experimental study it was observed that the temperature of the surface and air RH affected the rate of frost growth significantly while the air velocity did not have a great influence. It is demonstrated that a dry heat transfer correlation can be used during frost growth period by correctly accounting for frost thickness in the hydraulic diameter calculations. Ignoring the phenomenon of air redistribution was found to result in errors in the range of 20% to 50% in predicted frost thickness. Frost thickness predicted by the frost model is within 5% of the measured values for most of the cases. Frost mass accumulation predicted by the simple model is higher than the measured values due to a uniform thickness assumption in the model. An improved frost model based on 1-D finite volume discretization is also presented which improved the frost mass prediction to within 13% of measured values. The system simulation is validated against experimental results and found to match reasonable well. The discrepancy between simulation and experiments were due to the effects of system transience in the initial stages.

  14. Electoral Susceptibility

    CERN Document Server

    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...

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

    OpenAIRE

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

    2002-01-01

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

  16. Heat transfer and pressure drop amidst frost layer presence for the full geometry of fin-tube heat exchanger

    International Nuclear Information System (INIS)

    The present study numerically solves the flow and thermal fields in the full geometry of heat exchanger modeling with frost layer presence on the heat exchanger surface. The effects of air inlet velocity, air inlet temperature, frost layer thickness, fin pitch, fin thickness, and heat exchanger shape on the thermo-hydraulic performance of a fin-tube heat exchanger are investigated. Heat transfer rate rises with increasing air inlet velocity and temperature, and decreasing frost layer thickness and fin pitch. Pressure drop rises with increasing air inlet velocity and frost layer thickness, and decreasing fin pitch. The effect of fin thickness on heat transfer and pressure drop is negligible. Based on the present results, we derived the correlations, which express pressure drop and temperature difference between air inlet and outlet as a function of air inlet velocity and temperature, as well as frost layer thickness

  17. Effects of air flow maldistribution on refrigeration system dynamics of air source heat pump chiller under frosting conditions

    International Nuclear Information System (INIS)

    The effects of air flow maldistribution on the performance of an air source heat pump chiller under frosting conditions were investigated experimentally. The results indicated that air flow maldistribution was the dominant factor leading to hunting of the thermostatic expansion valve for medium and/or large size finned tube evaporators. With air flow maldistribution degree (AMD) increasing, frost occurred earlier, and the frost layer grew faster. The operating characteristics became lower when AMD was increased. We found such phenomenon seemed to be related to both the difference of refrigerant outlet superheat and the frosting velocity. In the hunting stage, the frost block effect became the main factor degrading the refrigeration system performance. With AMD increasing, the heat pump system pertinent performance data (suction pressure, evaporation temperature, discharge pressure, refrigerant outlet temperature, etc.) were degraded more dramatically

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

    DEFF Research Database (Denmark)

    Barber, D.; Ehn, J.

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

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

    Science.gov (United States)

    2007-01-01

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

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

    Scientific Electronic Library Online (English)

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

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

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

    Directory of Open Access Journals (Sweden)

    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 this re­gion, that had never been quantitatively studied the soils. Another relatively new fact is the methodology uses of the laser for par­ticle size analysis.

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

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jensen, Ole Mejlhede

    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 on how SAP influences concrete frost resistance. Moreover, it also presented a larger experimental study on the topic. The conclusions that were drawn from the experimental study were in line with the extract of the pool of results from the literature, first of all that SAP addition can improve frost resistance of concrete. The improvement was attributed to voids created by SAP. As was clearly demonstrated in the paper, it was crucial to document the void structure of the hardened concrete. Other factors than SAP could lead to void formation. For example, residue of surfactant on SAP particles, originating from the production of suspension polymerized SAP, can have an air entraining effect in concrete. Therefore, assuming that SAP generated voids are the only voids may lead to erroneous conclusions. When SAP is used, it is, in principle, possible to produce concrete with a pre-defined void structure as regards total void volume and void size. However, the optimum SAP void structure in relation to frost resistance is not known, and as long as the target is not clear, it is hard to use the design option of controlled void structure in a constructive way.

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

    Science.gov (United States)

    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.

  4. High-performance repair mortars for application in severe weathering environments: frost resistance assessment.

    Czech Academy of Sciences Publication Activity Database

    Janotová, Dana; Nunes, Cristiana Lara; Slížková, Zuzana; Frankeová, Dita; Niedoba, Krzysztof

    Glasgow : University of the West of Scotland, 2013 - (Hughes, J.) ISBN 978-1-903978-44-3 R&D Projects: GA MK(CZ) DF11P01OVV008 Keywords : mortar * frost * durability * hydrophobic Subject RIV: AL - Art, Architecture, Cultural Heritage

  5. Metabolite profiling during cold acclimation of Lolium perenne genotypes distinct in the level of frost tolerance.

    Science.gov (United States)

    Bocian, Aleksandra; Zwierzykowski, Zbigniew; Rapacz, Marcin; Koczyk, Grzegorz; Ciesio?ka, Danuta; Kosmala, Arkadiusz

    2015-11-01

    Abiotic stresses, including low temperature, can significantly reduce plant yielding. The knowledge on the molecular basis of stress tolerance could help to improve its level in species of relatively high importance to agriculture. Unfortunately, the complex research performed so far mainly on model species and also, to some extent, on cereals does not fully cover the demands of other agricultural plants of temperate climate, including forage grasses. Two Lolium perenne (perennial ryegrass) genotypes with contrasting levels of frost tolerance, the high frost tolerant (HFT) and the low frost tolerant (LFT) genotypes, were selected for comparative metabolomic research. The work focused on the analysis of leaf metabolite accumulation before and after seven separate time points of cold acclimation. Gas chromatography-mass spectrometry (GC/MS) was used to identify amino acids (alanine, proline, glycine, glutamic and aspartic acid, serine, lysine and asparagine), carbohydrates (fructose, glucose, sucrose, raffinose and trehalose) and their derivatives (mannitol, sorbitol and inositol) accumulated in leaves in low temperature. The observed differences in the level of frost tolerance between the analysed genotypes could be partially due to the time point of cold acclimation at which the accumulation level of crucial metabolite started to increase. In the HFT genotype, earlier accumulation was observed for proline and asparagine. The increased amounts of alanine, glutamic and aspartic acids, and asparagine during cold acclimation could be involved in the regulation of photosynthesis intensity in L. perenne. Among the analysed carbohydrates, only raffinose revealed a significant association with the acclimation process in this species. PMID:26025228

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

    Science.gov (United States)

    Yazdanpanah, H.; Stigter, C. J.

    2011-08-01

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

  7. Effect of pyraclostrobin on postharvest storage and quality of sugarbeet harvested before and after a frost

    Science.gov (United States)

    Pyraclostrobin and other strobilurin fungicides have been reported to have beneficial effects on productivity that cannot be attributed to disease control. Enhanced late-season frost tolerance is one such effect that has been observed for sugarbeet (Beta vulgaris L.) after a late season foliar pyra...

  8. What's Wrong with America's Playgrounds and How to Fix Them: An Interview with Joe L. Frost

    Science.gov (United States)

    American Journal of Play, 2008

    2008-01-01

    Joe L. Frost is Parker Centennial Professor Emeritus at the University of Texas, Austin, and one of America's leading experts on play and playgrounds. In addition to having taught child development and early childhood education at Texas and several other universities, he has written or edited fifteen university-level textbooks and more than one…

  9. Cross-Cultural Validity of the Frost Multidimensional Perfectionism Scale in Korea

    Science.gov (United States)

    Lee, Dong-gwi; Park, Hyun-joo

    2011-01-01

    This study with 213 South Korean college students (113 men) examined the cross-cultural generalizability of (a) the factor structure of the Frost Multidimensional Perfectionism Scale (F-MPS) and (b) the existence of adaptive perfectionists, maladaptive perfectionists, and nonperfectionists. A confirmatory factor analysis did not support the…

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

    Science.gov (United States)

    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.

  11. Control of dew and frost formation on leaf by radiative cooling

    International Nuclear Information System (INIS)

    A radiative cooling system was developed to control dew and frost formations and to examine the effect of the radiative cooling on the leaf temperature. The growth chamber was provided with a box which was constructed by using heat insulating materials to minimize the disturbances and to regulate the air current. A cooling coil (cooling surface of 300 cm was equipped at the bottom of the box and manipulated by a refrigerator of 1, 430 kcal hour-1, and a concave mirror was attached to the ceiling of the box to facilitate the reflection of the radiation from the leaf to the cooling coil. The moisture in air was supplied by flowing the controlled air (0.2 m min-1) into the box. The distribution of dew point temperatures was almost uniform horizontally even under vertically slight conversion (downward velocity of 1.3 cm sec-1) of the air. The leaf temperature became about 1.0°C lower than the ambient air temperature under the radiative cooling. The dew and the frost were clearly observed on the leaf after the time when the leaf temperature had become lower than the dew point temperature. The dew increased in size in course of time, and the frost varied in shape and in size with the temperatures. Thus, artificial formations of the dew and the frost were made possible by the radiative cooling system developed in this experiment

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

    Directory of Open Access Journals (Sweden)

    E. Beaudon

    2009-02-01

    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 species and a winter snow layer that is relatively depleted in sulphate. One part of the winter snow pack exhibits [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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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. PMID:26313967

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

    Science.gov (United States)

    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 potential to detect the impact of climatic effects, such as frost, on crop growth, which is relevant information to evaluate the negative impact on sugarcane production. Thus, the objective of the present study is to detect the impact of the frost occurred on 28 June 2011 in the sugarcane production region of São Paulo state, using MODIS images acquired on board of Terra and Aqua satellites before and after the frost event. Also, Landsat type images were used to map the harvested sugarcane fields up to the frost event based on a sugarcane crop map for year 2011. The remaining sugarcane fields available for harvest in 2011 were monitored with the MODIS images acquired on 17, 19, 27, 28 June and 8 and 9 July, to detect frost damage. Field work was conducted shortly after frost occurrence to identify sugarcane fields with frost damage for training and validation purposes. MODIS images transformed to vegetation indices and morphometric variables extracted from SRTM (Shuttle Radar Topography Mission) data are being analyzed to detect and quantify the damage of the frost from 28 July 2011 on sugarcane crop.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Soil proteomics

    DEFF Research Database (Denmark)

    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...... 2 and 3) 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...

  19. Puerto Rico Soil Erodibility (Kffact)

    Data.gov (United States)

    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.

  20. Puerto Rico Soil Erodibility (Kffact)

    Data.gov (United States)

    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.

  1. FROST - FReezing Of coated and uncoated duST particles

    Science.gov (United States)

    Wex, H.

    2009-04-01

    In April 2008, the measurement campaign FROST (FReezing Of coated and uncoated duST particles) was conducted at the ACCENT (Atmospheric Composition Change - the European NeTwork of excellence) infrastructure site LACIS (Leipzig Aerosol Cloud Interaction Simulator). During the campaign, size selected coated and uncoated Arizona Test Dust (ATD) particles were characterized with respect to shape, chemical composition, hygroscopic growth and activation, and their ability to act as IN (Ice Nuclei). The ATD particles were dispersed by means of a fluidized bed generator. Coatings were applied in different furnaces, operated at different temperatures. The coatings were either succinic acid, sulphuric acid, or ammonium sulphate. A DMA (Differential Mobility Analyzer) was used for selecting particles with a mobility diameter of 300 nm. The following measurements were done: Three AMS (Aerosol Mass Spectrometers, e.g. Schneider et al. (2005) and references therein) were used to determine particle composition. Particles were collected on grids for subsequent TEM (Transmission Electron Micoscropy) analysis. Hygroscopic growth factors were determined by means of a HH-TDMA (High Humidity Tandem Differential Mobility Analyzer) that measured up to relative humidities (RH) of 98% (Hennig et al. (2005)). The critical super-saturations needed for the activation of the investigated particles into cloud droplets were measured with a continuous flow CCNc (Cloud Condensation Nucleus counter) from DMT (Droplet Measurement Technologies, Roberts and Nenes (2005)). The LACIS flow tube was extended to a length of 8 m, so LACIS could be used to examine the immersion freezing behaviour of the coated and uncoated ATD particles. By a bulk analysis and by the AMS measurements, the ATD particles were found to contain water soluble material, however in small quantities. By means of the online AMS measurements, it was possible to distinguish between thin and thick H2SO4 coatings. For the thin coatings, the H2SO4 was found to have reacted with material contained in the ATD, so that almost no free H2SO4 was found. For the thick coatings, obtained at higher coating temperatures, H2SO4 was detected. In general, uncoated particles and those coated with thin coatings of H2SO4 or of succinic acid, showed almost no hygroscopic growth. Particles coated with thicker coatings of H2SO4 and of ammonium sulphate grew noticeably above 95% RH (growth factors of about 1.1 at 98% RH). Both, coated and uncoated ATD particles, were found to activate at atmospherically relevant super-saturations (0.35% for pure ATD, 0.2% for succinic acid and thin H2SO4 coatings, 0.15% for thick H2SO4 and for ammonium sulphate coatings). Combining measured hygroscopic growth with activation data, a dynamic shape factor of the ATD particles of about 1.8 was derived, corroborating the deviation of the particle shape from that of a sphere. Uncoated ATD particles and particles coated with succinic acid or thin coatings of H2SO4 nucleated ice at higher temperatures, i.e. were more efficient IN, than particles with thick H2SO4 or ammonium sulphate coatings. Although the latter two were similar in hygroscopic growth and activation behaviour, they differed in their ability to act as IN, with ATD particles coated with ammonium sulphate being the most ineffective IN. This finding suggests that the investigated particle's ability to act as IN might not be related to water activity for the immersion freezing processes investigated in this study. References: Hennig, T., A. Massling, F. Brechtel, and A. Wiedensohler (2005), A tandem DMA for highly temperature-stabilized hygroscopic particle growth measurements between 90% and 98% relative humidity, J. Aerosol Sci., 36, 10, 1210-1223. Roberts, G., and A. Nenes (2005), A continuous-flow streamwise thermal-gradient CCN chamber for atmospheric measurements, Aerosol Sci. Technol., 39, 206-221. Schneider, J., N. Hock, S. Weimer, S. Borrmann, U. Kirchner, R. Vogt, and V. Scheer (2005), Nucleation particles in Diesel exhaust: Composition inferred from in situ mass sp

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

    DEFF Research Database (Denmark)

    Barber, D.; Ehn, J.; Pucko, M.; Rysgaard, Søren; Deming, J. W.; Bowman, J.S.; Papakyriakou, T. N.; Galley, R.J.; Søgaard, DH

    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 becomes available to a cold atmosphere and surface winds are low, allowing for supersaturation of the near-surface boundary layer. Ice grown in a pond cut in young ice at the mouth of Young Sound, NE Gr...

  3. Dose-response curve to soil applied herbicides and susceptibility evaluation of different amaranthus species using model identity / Curva dose-resposta de herbicidas aplicados ao solo e avaliação da susceptibilidade de diferentes espécies de amaranthus pela identidade de modelos

    Scientific Electronic Library Online (English)

    M.A., RAIMONDI; R.S., OLIVEIRA J.R.; J., CONSTANTIN; F.A., RIOS; A., GEMELLI; R.T., RAIMONDI.

    2015-03-01

    Full Text Available Em 2008/2009 foram conduzidos estudos em casa de vegetação com o objetivo de ajustar curvas de dose-resposta dos principais herbicidas usados atualmente em pré-emergência no algodoeiro para controle de Amaranthus viridis, A. hybridus, A. spinosus e A. lividus, bem como para comparar a suscetibilidad [...] e entre espécies diferentes, utilizando o teste de identidade de modelos. Trinta e seis experimentos individuais foram realizados simultaneamente em casa de vegetação, empregando solo franco-arenoso (argila, 21%; OM, 2,36%), combinando doses crescentes dos herbicidas alachlor, clomazone, diuron, oxyfluorfen, pendimethalin, prometryn, S-metolachlor e trifluralin, aplicadas a cada uma das espécies. As curvas de dose-resposta foram ajustadas em relação à avaliação de controle visual das plantas daninhas aos 28 dias após a aplicação dos herbicidas, sendo calculadas doses necessárias para o controle de 80% (C80) e 95% (C95). Todos os herbicidas, com exceção de clomazone e trifluralin, resultaram em controle eficiente da maioria das espécies de Amaranthus, porém diferenças substanciais na suscetibilidade aos herbicidas foram encontradas. Em geral, A. lividus foi a espécie menos sensível, ao passo que A. spinosus demonstrou a maior sensibilidade aos herbicidas. Alachlor, diuron, oxyfluorfen, pendimethalin, S-metolachlor e prometryn são alternativas eficientes para controle de Amaranthus spp. em uma faixa de doses que se encontram inferiores às recomendadas atualmente para o algodão. Abstract in english Greenhouse studies were conducted in 2008-2009 with the objective of adjusting dose-response curves of the main soil-applied herbicides currently used in cotton for the control of Amaranthus viridis, A. hybridus, A. spinosus, A. lividus, as well as comparing susceptibility among different species, u [...] sing the identity test models. Thirty six individual experiments were simultaneously carried out in greenhouse, in a sandy clay loam soil (21% clay, 2.36% OM) combining increasing doses of the herbicides alachlor, clomazone, diuron, oxyfluorfen, pendimethalin, prometryn, S-metolachlor, and trifluralin applied to each species. Dose-response curves were adjusted for visual weed control at 28 days after herbicide application and doses required for 80% (C80) and 95% (C95) control were calculated. All herbicides, except clomazone and trifluralin, provided efficient control of most Amaranthus species, but substantial differences in susceptibility to herbicides were found. In general, A. lividus was the least sensitive species, whereas A. spinosus demonstrated the highest sensitivity to herbicides. Alachlor, diuron, oxyfluorfen, pendimethalin, S-metolachlor, and prometryn are efficient alternatives to control Amaranthus spp. in a range of doses that are currently lower than those recommended to cotton.

  4. Survival, frost susceptibility, growth, and disease resistance of corkbark and subalpine fir grown for landscape and Christmas trees

    Science.gov (United States)

    Trees from six corkbark fir (Abies lasiocarpa var. arizonica) and 10 subalpine fir (A. lasiocarpa var. lasiocarpa) seed sources were grown at the University of Idaho Sandpoint Research and Extension Center (SREC) and two commercial nurseries in Idaho and Oregon. Post transplant mortality was highest...

  5. A model of frost heave with sharp interface between the unfrozen and the frozen soils

    OpenAIRE

    Talamucci, Federico

    1996-01-01

    Quando un suolo umido è sottoposto ad un processo di congelamento, si osserva in generale un'espansione di volume. L'aumento di volume è dovuto principalmente ad una migrazione di acqua dalla base del suolo verso il fronte di congelamento, che separa la zona non congelata, in basso, da quella, superiore, completamente congelata. Il processo accoppiato di trasferimento di massa e calore si accompagna, in determinate condizioni, alla formazione di strati segregati di ghiaccio puro ("lenti di gh...

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

    Scientific Electronic Library Online (English)

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

    2010-03-01

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

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

    Science.gov (United States)

    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.

  8. Laboratory determination of frosting and defrosting losses for a high efficiency air-source heat pump

    Science.gov (United States)

    Miller, W. A.; Ellison, R. D.

    Tests to detail system and component performance data, to quantify the dynamic losses, and to seek and evaluate methods for reducing these losses were performed. A high efficiency split-system heat pump was installed in two separate air loops, with one loop housing the indoor and the other housing the outdoor unit. Calculations of the heat pump's performance based on air-side measurements were within 3% of that based on refrigerant side measurements. Performance of the heat pump was measured under steady-state, dehumidification, and frosting-defrosting conditions with major emphasis placed on the dynamic frosting operation of the system. The system and component performance was evaluated for ambient temperature levels of 8.3, 4.4, 1.7, -1.1 and -8.3 C, and for discrete humidity levels ranging from 50 to 90%.

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

    Directory of Open Access Journals (Sweden)

    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 %.

  10. Study of the thermal behavior of a latent heat cold storage unit operating under frosting conditions

    International Nuclear Information System (INIS)

    A study is performed of the thermal behavior of a latent heat cold storage unit operating under frosting conditions. This unit is employed to maintain the temperature inside the refrigerated compartment of a truck below 265 K. The system consists of parallel plates filled with a phase change material (PCM) that absorbs heat from the flow of warm moist air. A mathematical model for the system is first presented and, next, validated with numerical and experimental data. It is then exploited to assess the effects of design parameters and operating conditions on the performance of the system. The recommended thickness and distance separating the PCM plates are found to be 50x10-3 and 30x10-3 m, respectively. The results indicate that the performance of the unit is enhanced by turbulent air flow in spite of the increased pressure loss and accentuated frost growth. The unit also performs well even when the surrounding relative humidity is 100%

  11. Grand canonical Monte Carlo simulation of adsorption of helium on cryogenic argon frost

    International Nuclear Information System (INIS)

    Cryosorption pumping of non-condensable gas, using charcoal, molecular sieves and condensed layers of certain gases, such as Ar, CO2, SF6, and N2, as sorbents, is an efficient method to obtain ultra-high vacuum in cryogenic engineering. Molecular modeling provides a convenient way to understand the principle of adsorption proceeding in microscopic view. Helium adsorption in argon frost at 4.5K has been simulated using the grand canonical Monte Carlo method in this paper. The HFD-B (HE) Aziz potential was used for the He-He pair interaction. The simulated adsorption isotherm of Helium in argon frost was obtained. Additionally, the simulation results were compared with the historic experimental data. (author)

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

    Directory of Open Access Journals (Sweden)

    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 out of the brine layer for the possible acidification of the liquid phase by acid uptake. Our investigation showed that this precipitation is a crucial process for the timing of the bromine explosion in aerosols. Nevertheless, model runs with either 50% precipitation or complete precipitation displayed a relatively weak difference in ozone mixing ratios after four simulated days. By considering conditions typical for "Arctic Haze" pollution events at the start of the run we obtained a low pH in frost flower aerosols due to a greater mixing ratio of SO2, and a strong recycling efficiency via large aerosol number concentration. The aerosol acidification during a haze event most likely intensifies the ozone depletion strength and occurrence. The comparison between our modeled deposition on snow and sampled snow at Barrow (Alaska shows that approximately 75% of deposited bromine may be re-emitted into the gas phase as Br2/BrCl. Among several non-halogen fluxes from the snow, model simulations showed that only HONO affects the chemistry. Finally, we investigated the release of Br2 potentially produced by heterogeneous reactions directly on frost flowers. In this case, we obtained unrealistic results of aerosol compositions and deposition rates on snow compared to observations in the Arctic.

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

    Directory of Open Access Journals (Sweden)

    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 out of the brine layer for the possible acidification of the liquid phase by acid uptake. Our investigation showed that this precipitation is a crucial process for the timing of the bromine explosion in aerosols. Nevertheless, model runs with either 50% precipitation or complete precipitation displayed a relatively weak difference in ozone mixing ratios after four simulated days. By considering conditions typical for "Arctic Haze" pollution events at the start of the run we obtained a low pH in frost flower aerosols due to a greater mixing ratio of SO2, and a strong recycling efficiency via large aerosol number concentration. The aerosol acidification during a haze event most likely intensifies the ozone depletion strength and occurrence. The comparison between our modeled deposition on snow and sampled snow at Barrow (Alaska shows that approximately 75% of deposited bromine may be re-emitted into the gas phase as Br2/BrCl. Among several non-halogen fluxes from the snow, model simulations showed that only HONO affects the chemistry. Finally, we investigated the release of Br2 potentially produced by heterogeneous reactions directly on frost flowers. In this case, we obtained unrealistic results of aerosol compositions and deposition rates on snow compared to observations in the Arctic.

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

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

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

  15. Dissecting the genetic architecture of frost tolerance in Central European winter wheat

    OpenAIRE

    Zhao, Yusheng; Gowda, Manje; Würschum, Tobias; Longin, C. Friedrich H.; Korzun, Viktor; Kollers, Sonja; Schachschneider, Ralf; Jian ZENG; Fernando, Rohan; Dubcovsky, Jorge; Reif, Jochen C.

    2013-01-01

    Abiotic stress tolerance in plants is pivotal to increase yield stability, but its genetic basis is still poorly understood. To gain insight into the genetic architecture of frost tolerance, this work evaluated a large mapping population of 1739 wheat (Triticum aestivum L.) lines and hybrids adapted to Central Europe in field trials in Germany and fingerprinted the lines with a 9000 single-nucleotide polymorphism array. Additive effects prevailed over dominance effects. A two-dimensional geno...

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

    OpenAIRE

    Ellen Pflug; Wolfgang Brüggemann

    2012-01-01

    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 un...

  17. Effectiveness of Bumblebee Pollination in Anti-Frost Heated Tomato Greenhouses in the Mediterranean Basin*

    OpenAIRE

    DA?GAN, H. Y?ld?z; ÖZDO?AN, A. O.

    2004-01-01

    Turkey has 22,000 ha of greenhouse area, and about 51% of vegetable greenhouses are used for tomato production. In Mediterranean countries generally greenhouses are not regularly heated at optimal levels. Fruity vegetables in winter have a problem of insufficient pollination due to low temperatures and isolated atmosphere. The aim of this study was to investigate the effectiveness of bumblebee (Bombus terrestris) pollination in tomato production in anti-frost heated greenhouses in the Mediter...

  18. Short communication. Harvest time in hedgerow ‘Arbequina’ olive orchards in areas with early frosts

    OpenAIRE

    Gracia Gimeno, María Pilar; Sánchez-Gimeno, Ana Cristina; Benito, Marta; Oria, Rosa; Lasa Dolhagaray, José Manuel

    2012-01-01

    [EN] 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 ...

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

    Scientific Electronic Library Online (English)

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

    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. Abstract in english The development of a computational code that simulates the formation and frost growth on a cool plate, for the vapor-water ablimation of a humid air current that flows on it, is presented. The numeric modeling is based on the conservation equations of mass, energy, momentum and species applied to th [...] e frost, air-vapor mixtures and air-frost interface. The system of equations is not linear and is coupled by the ice volumetric fraction which is calculated by iteration. The model is validated by comparing the numerical results with experimental data, reproducing the thermophysical properties evolution of the frost formed and predicting the behavior for other operating conditions. The results reveal better agreement with experimental data that those obtained by other authors, and slightly inferior to that of the supersaturation model.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  3. Proteomic and metabolomic profiling of Valencia orange fruit after natural frost exposure.

    Science.gov (United States)

    Perotti, Valeria E; Moreno, Alejandra S; Trípodi, Karina E J; Meier, Guillermo; Bello, Fernando; Cocco, Mariángeles; Vázquez, Daniel; Anderson, Catalina; Podestá, Florencio E

    2015-03-01

    The aim of this study was to evaluate the response of orange fruit (Citrus sinensis var. Valencia Late) to freezing stress in planta, both immediately after the natural event and after a week, in order to understand the biochemical and molecular basis of the changes that later derive in internal and external damage symptoms. Using two-dimensional differential gel electrophoresis to analyze exposed and non-exposed fruit, 27 differential protein spots were detected in juice sacs and flavedo, among all comparisons made. Also, primary and secondary metabolites relative contents were analyzed in both tissues by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, respectively. Proteins and compounds involved in regulatory functions, iron metabolism, oxidative damage and carbohydrate metabolism were the most affected. Interestingly, three glycolytic enzymes were induced by cold, and there was an increase in fermentation products (volatiles); all of that suggests that more energy generation might be required from glycolysis to counter the cold stress. Moreover, a notable increase in sugar levels was observed after frost, but it was not at the expense of organic acids utilization. Consequently, these results suggest a probable redistribution of photoassimilates in the frost-exposed plants, tending to restore the homeostasis altered by that severe type of stress. Isosinensetin was the most cold-sensitive secondary metabolite because it could not be detected at all after the frost, constituting a possible tool to early diagnose freezing damage. PMID:25132553

  4. Numerical Simulation of Plain Fin-and-Round Tube Heat Exchanger under Frost Condition

    Science.gov (United States)

    Hussein, Amar Ali; Talib, A. R. Abu; Adam, N. M.

    2010-06-01

    Three-dimensional numerical simulations are carried out to investigate the amount of heat transfer of a plain fin-and-four staggered layout and round tube rows for different fin pitch namely 25.4, 12.7, 6.35 and 4.23 mm. The simulations were conducted for two different frost thermal conductivity of 0.1 and 0.3 W/m-1K-1 using FLUENT 6.3 CFD code. The amount of heat transfer of the plain fin-and-round tube heat exchanger under frost condition (0, 1, 2, and 3 mm frost thickness) was investigated. Fluid flow and heat transfer are simulated and results calculated using two turbulence models (k-epsilon, and Transitional SST k-omega), with steady-state solver. Model validation was carried out by comparing the pressure drop of simulated case to experimental results from the literature. Reasonable agreement was found between the present simulations compared to existing numerical study and experimental data.

  5. Five second helium neutral beam injection using argon-frost cryopumping techniques

    International Nuclear Information System (INIS)

    High power helium neutral beams for the heating of tokamak discharges can now be provided for 5 s by using argon cryopumping (of the helium gas) in the beamlines. The DIII-D neutral beam system has routinely provided up to 20 MW of deuterium neutral beam heating in support of experiments on the DIII-D tokamak. Operation of neutral beams with helium has historically presented a problem in that pulse lengths have been limited to 500 ms due to reliance solely on volume pumping of the helium gas. Helium is not condensed on the cryopanels. A system has now been installed to deposit a layer of argon frost on the DIII-D neutral beam cryopanels, between tokamak injection pulses. The layer serves to trap helium on the cryopanels providing sufficient pumping speed for 5 s helium beam extraction. The argon frosting hardware is now present on two of four DIII-D neutral beamlines, allowing injection of up to 6 MW of helium neutral beams per discharge, with pulse lengths of up to 5 s. The argon frosting system is described, along with experimental results demonstrating its effectiveness as a method of economically extending the capabilities of cryogenic pumping panels to allow multi-second helium neutral beam injection

  6. The risk of early and late frost behavior in central México under El Niño conditions

    Scientific Electronic Library Online (English)

    A. R, PERALTA-HERNÁNDEZ; L. R, BARBA-MARTÍNEZ.

    2009-01-01

    Full Text Available El problema de la presencia irregular de bajas temperaturas (heladas) en el centro de México (~19-23° N) causa pérdidas elevadas en la producción agrícola año tras año, afectando principalmente a cultivos que son sensibles a las temperaturas bajas con importantes implicaciones socioeconómicas. En el [...] centro de México, existe carencia de estudios sobre las heladas en relación a su duración especialmente en respuesta al fenómeno de El Niño (EN). Debido a la accidentada orografía del terreno las estaciones climatológicas se agruparon en rangos de 300 m de altura, resultando cinco regiones: I, III, IV-VI con elevaciones de 875 a 2999 msnm, conformadas por 50 estaciones con datos de temperaturas mínimas diarias ( Abstract in english The irregular occurrence of cold temperatures (frost) in central México (~19-23° N) produces high agricultural losses each year; the greatest effect is on cold-sensitive crops, which has important socio-economic implications for the region. There is a lack of information on frost-related studies reg [...] arding the onset and duration of frosts in central México, especially in response to the El Niño (EN) phenomenon. Due to the land's irregular topography, the weather stations were grouped into 300 m range heights, resulting in five regions: I, III, and IV-VI with elevations from 875 to 2999 masl. Daily minimum temperatures (

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

    Directory of Open Access Journals (Sweden)

    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. Aclimatação ao frio e dano por geada em canola / Acclimatization to cold and frost-injury in canola

    Scientific Electronic Library Online (English)

    Genei Antonio, Dalmago; Gilberto Rocca da, Cunha; Anderson, Santi; João Leonardo Fernandes, Pires; Alexandre Luiz, Müller; Laise Maria, Bolis.

    2010-09-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência da aclimatação ao frio sobre o dano causado pela geada em diferentes estádios fenológicos de genótipos de canola. Foram realizados cinco experimentos em ambiente controlado, em 2006, 2007 e 2008. Os fatores avaliados foram: genótipos, aclimatação (c [...] om; sem), intensidades de geada, estádios de desenvolvimento de plantas, regimes de aclimatação e regimes de geada. As variáveis avaliadas foram: queima de folhas, massa de matéria seca, estatura de plantas, duração de subperíodo, componentes de rendimento e rendimento de grãos. A aclimatação ao frio, antes da geada, resultou em menor queima de folhas e maior massa de matéria seca, em comparação a plantas não aclimatadas. As geadas foram prejudiciais a partir de -6°C no início do ciclo de desenvolvimento, principalmente em plantas não aclimatadas, e a partir de -4ºC na floração, com redução do número de síliquas e do número de grãos por síliqua. A aclimatação após as geadas não contribuiu para a tolerância da canola a esse evento. Geadas consecutivas não acarretaram maior prejuízo à canola. A aclimatação de plantas de canola antes da geada reduz os danos, principalmente quando a geada ocorre no início do desenvolvimento das plantas. Abstract in english The objective of this work was to evaluate the influence of cold acclimatization on frost damage at different phenological stages of canola genotypes. Five experiments were carried out under controlled conditions, in 2006, 2007, and 2008. The evaluated factors were: genotypes, acclimatization (with; [...] without), frost gradient, plant developmental stages, acclimatization regimes and frost regimes. The evaluated variables were: leaf scorching symptoms, dry weight, plant height, length of subperiod, yield components and grain yield. The acclimatization before frost resulted in lesser leaf scorching symptoms and higher dry matter in comparison to plants not acclimated. Frosts were harmful from -6°C in early plant development stage, mainly in nonacclimated plants, and from -4ºC at flowering, reducing the number of pods and the number of grains per pod. Acclimatization after frost did not contribute to the tolerance of canola to frost. Consecutive frosts caused no greater impairment to canola. The canola acclimatization before frost reduces damage caused by it, mainly when the frost occur in the initial plant development stages.

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

    Directory of Open Access Journals (Sweden)

    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 seedlings. It is supposed that increasing of cold and frost resistance of winter and spring wheat caused by seed treatment of the tebuconazole-based protectant may be associated with increase of the abscisic acid content – one of the triggers of the low-temperature adaptation of plants. It is concluded that tebuconazole-based protectant of seeds «Bunker» increases the resistance of wheat to low temperature, affecting the growth processes and the synthesis of stress proteins.

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

    OpenAIRE

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

    2014-01-01

    The objective of this study is to analyze frost damaging events in agriculture, by examining the relationship between the daily minimum temperature at the lower atmosphere (at the pressure level of 850 hPa) and crop production losses. Furthermore, the study suggests a methodological approach for estimating agriculture risk due to frost events, with the aim to estimate the short-term probability and magnitude of frost-related financial losses for different levels of 850 hPa t...

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

    Science.gov (United States)

    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 Atlantic coast of the country. The former presents a linear trend in the FP, while the other shows a decadal variability. Regarding the frost intensity we analysed the consecutive frost days (CFD) index, which shows that the usual length is around 2-4 days. The decadal analysis shows that during the first decades events lasting 4-5 days were common, while in the last decades isolated events were detected. We also study the intensity considering the occurrence of events in different ranges of temperature: [0,-1], [-1,-2] and below -2°C. Overall, during the 90's there are more events below -2 °C, while during the 2000s although there were fewer events in the coastal stations they are more intense. Relationships with large scale anomalies circulations were also studied.

  12. THE EFFECT OF CULTIVAR AND BEARING TREE ON BUD DIFFERENTIATION, FROST DAMAGE AND FRUIT SET IN APPLE

    Directory of Open Access Journals (Sweden)

    Nikola Pavi?i?

    2004-06-01

    Full Text Available After severe winter frost, an examination was initiated of frost damage suffered by Idared and Golden Delicious clone B. The cultivars differed significantly in the differentiation intensity, the hare of damaged differentiated buds, but not in share of damaged undifferentiated buds. In both cultivars the bud damage was more intensive on long bearing wood than on spur, regardless differentiation grade. The interaction between the cultivar and the bearing wood was insignificant. The flower bud differentiation was better in Idared, but it also suffered more frost damage than the Golden Delicious clone B with differentiated buds, but not than that with undifferentiated buds. In both cultivars frost damage increases with increase of differentiated flower buds (R2=0.759; P?0.001. The fruit set was within the limits of expectation only on the spurs of the Golden Delicious clone B, which showed strong tendency towards fruit set on long bearing shoots. In 2000, the yield of the cultivars was almost equal, as the result of thinning due to the frost damage on Idared.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ivan Granemann de Souza Junior

    2010-03-01

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

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

    Science.gov (United States)

    Kim, Jin-Ah; Byun, Hi-Ryong

    2016-02-01

    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.

  16. Acclimation to frost alters proteolytic response of wheat seedlings to drought.

    Science.gov (United States)

    Grudkowska, Ma?gorzata; Zagda?ska, Barbara

    2010-11-01

    A comparative examination of cysteine proteinases in winter wheat (Triticum aestivum L.) seedlings differing in sensitivity to frost and drought revealed many similarities and differences in response to water deprivation. Azocaseinolytic activity was enhanced under water deficiency, but the enhancement was significantly lower in the tolerant genotype (Kobra cultivar). On the contrary, acclimation of wheat seedlings at low temperature had no effect on the proteolytic activity of the tolerant cultivar and depressed the azocaseinolytic activity of the sensitive cultivar (Tortija). However, the observed depression of enzyme activity was fully reversible under dehydration. The content of soluble proteins was reduced in dehydrated non-acclimated and in acclimated seedlings of the frost-sensitive cultivar, but increased in acclimated seedlings of the tolerant cultivar. The cysteine proteinases were preferentially induced under water deficiency when assessment was based on the inhibitory effect of iodoacetate on azocasein hydrolysis. Separation of cysteine proteinases by SDS-PAGE containing gelatin as a substrate showed two bands with apparent molecular masses of 36 and 38 kDa in the sensitive cultivar, and a third band was detected (42 kDa) in the resistant cultivar. Water deficit and low temperature induced the new cysteine proteinases of molecular masses about 29, 33 and 42 kDa in sensitive non-acclimated seedlings. Polyclonal antibodies raised against Arabidopsis proteinase responsive to drought (RD21) cross-reacted with the protein in the 33 kDa region, and a slight signal was obtained in the 42 kDa region, but only in dehydrated seedlings acclimated to frost. Several polypeptides of molecular masses of 30, 22, 20 and 18 kDa were recognized by the Arabidopsis aleurain-like proteinase (AtALEU) antibodies. The results presented indicate that cysteine proteinases are potentially responsible for both low temperature and drought tolerance. PMID:20674076

  17. Unity of Harmonious Rhythms and the Form in a Poem: an Analysis of Robert Frost’s Stopping by Woods on a Snowy Evening from the angle of rhythms

    Directory of Open Access Journals (Sweden)

    Min DU

    2006-03-01

    Full Text Available The rhythms and the form in the poem are mutually dependent .This thesis tries to analyze Robert Frost’s poem Stopping by Woods on a Snowy Evening from the angle of rhythms and appreciate the beauty of the content and the form , which helps to understand the connotation of the poem and reveal the complex feelings of the poet .
    Key words: rhythms, the form of the poem
    Résumé La rime et la forme dans un poème sont dépendantes mutuellement. L’article essaie d’analyser le poème S’arrêter au bord de la forêt dans une nuit de neige de Robert Frost du point de vue de la rime et interpreter la forme de sa rime pour apprécier les beautés du contenu et de la forme du poème, cela favorise la révélation de la signification du poème et des sentiments complexes du poète.
    Mots clés: la rime, la forme du poème
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  18. Coagulation of particles in Saturn's rings - Measurements of the cohesive force of water frost

    International Nuclear Information System (INIS)

    Experimental data are presented on the sticking force of water ice particles which are indicative of the role that the cohesive properties of such particles could play in the dynamics of Saturn ring particles. Sticking forces are dependent on particle impact velocities; a Velcro model is devised to describe the surface structure involved in sticking. The data indicate that below the critical impact velocity of about 0.03 cm/sec, particle cohesion always occurs. Due to the optical depth of micron-sized grains in the Saturn rings, particles are hypothesized to be coated with a layer of frost which will render cohesion an important ring-dynamics process. 14 refs

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

    International Nuclear Information System (INIS)

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

  20. CLAS+FROST: new generation of photoproduction experiments at jefferson lab

    International Nuclear Information System (INIS)

    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. (author)

  1. Determination of E and G Observables in ? Photoproduction on the Clas Frozen Spin Target (frost)

    Science.gov (United States)

    Senderovich, Igor; Morrison, B. T.; Dugger, M.; Ritchie, B.; Tucker, R.

    2014-01-01

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

  2. Plenary Talk: CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab.

    Science.gov (United States)

    Pasyuk, E.

    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.

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

    Science.gov (United States)

    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 also a potential to enhance conventional field-based surveying for monitoring frost changes over long timescales. KEYWORDS: Earth Observation, MODIS, frost, risk assessment, Greece

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

    International Nuclear Information System (INIS)

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

  5. Numerical simulation of moisture migration depending on the rate of soil freezing

    Directory of Open Access Journals (Sweden)

    A.V. Kazharskiy

    2012-06-01

    Full Text Available One of the geomechanics challenges is the quantitative assessment of deformation of soils associated with frost heaving and thawing. The main difficulty in solving this problem is the need to consider changing the state of soil freezing and thawing ground and thermophysical characteristics of the medium in a transient state. The main process in frozen soil is the redistribution of moisture in them due to water migration during freezing. When water freezes, the soil characteristics, its physical and mechanical properties change.This paper includes description of a numerical simulation method and study about humidity changing in frozen soils, depending on the rate of soil freezing. The influence of soil humidity changing on the values of strength characteristics during the process of thawing is evaluated.The developed technique of numerical simulation of the freezing and thawing process allows assessing the impact of frost heaving forces, decreasing the strength of buildings foundations and structures during freezing and thawing at the design stage. This allows the effective implementing of modern structures for soils and foundations reinforcement using geosynthetics to reduce or eliminate frost heave processes and thawing.

  6. Zwitter-wettability and antifogging coatings with frost-resisting capabilities.

    Science.gov (United States)

    Lee, Hyomin; Alcaraz, Maria L; Rubner, Michael F; Cohen, Robert E

    2013-03-26

    Antifogging coatings with hydrophilic or even superhydrophilic wetting behavior have received significant attention due to their ability to reduce light scattering by film-like condensation. However, under aggressive fogging conditions, these surfaces may exhibit frost formation or excess and nonuniform water condensation, which results in poor optical performance of the coating. In this paper, we show that a zwitter-wettable surface, a surface that has the ability to rapidly absorb molecular water from the environment while simultaneously appearing hydrophobic when probed with water droplets, can be prepared by using hydrogen-bonding-assisted layer-by-layer (LbL) assembly of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA). An additional step of functionalizing the nano-blended PVA/PAA multilayer with poly(ethylene glycol methyl ether) (PEG) segments produced a significantly enhanced antifog and frost-resistant behavior. The addition of the PEG segments was needed to further increase the nonfreezing water capacity of the multilayer film. The desirable high-optical quality of these thin films arises from the nanoscale control of the macromolecular complexation process that is afforded by the LbL processing scheme. An experimental protocol that not only allows for the exploration of a variety of aggressive antifogging challenges but also enables quantitative analysis of the antifogging performance via real-time monitoring of transmission levels as well as image distortion is also described. PMID:23360374

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

    Directory of Open Access Journals (Sweden)

    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.

  8. The "Mechanostat Theory" of Frost and the OPG/RANKL/RANK System.

    Science.gov (United States)

    Tyrovola, Joanna B; Odont, X X

    2015-12-01

    Frost's great interest to elucidate the principles of action underlying skeletal deformities, during, and after growth, urged him to undertake an extensive study of the mammalian skeleton. He suggested that survival of the skeleton (but also of other tissues, such as fibrous tissue, hyaline cartilage, fibrocartilage, cementum, or dentin) requires the functional coordination of modeling and remodeling. Modeling adapts bone to overloads, by enhancing additions of new bone and by changing bone architecture, and remodeling adapts bone to underloads by removing bone next to marrow and conserving normally used bone. There exists a mechanism that monitors bone metabolism (longitudinal growth, bone modeling, and remodeling activities) in relation to mechanical usage, the "mechanostat." Recent literature has presented new information regarding the physiological procedure of osteoclast and osteoblast activation. It has been understood that the OPG/RANKL/RANK proteinic system regulates bone metabolism by exerting biological effects on osteoblasts or osteoclasts. The same proteinic network, also regulates alveolar remodeling during tooth movement, as well as physiological root resorption and root resorption during orthodontic tooth movement. The aim of the present review is the presentation and evaluation of recent information in the field of osteoclast and osteoblast biology, as regards to the "mechanostat theory" of Frost. An attempt will be made to elucidate, whether recent data can support this remarkable theory and reveal the biological mechanisms behind it. PMID:26096594

  9. Facile fabrication of biomimetic superhydrophobic surface with anti-frosting on stainless steel substrate

    Science.gov (United States)

    Liu, Yan; Bai, Yuan; Jin, Jingfu; Tian, Limei; Han, Zhiwu; Ren, Luquan

    2015-11-01

    Inspired by typical plant surfaces with super-hydrophobic character such as lotus leaves and rose petals, a superhydrophobic surface was achieved successfully by a chemical immersion process. Here, 304 SS (stainless steel) was used as substrates and a micro-nano hierarchical structure was obtained by chemical etching with a mixed solution containing ferric chloride. The results showed that the water contact angle (WAC) decreased obviously due to surface morphology changing after chemical etching process. However, we obtained a superhydrophobic surface with a WAC of 158.3 ± 2.8° after modification by DTS (CH3(CH2)11Si(OCH3)3). Furthermore, the superhydrophobic surface showed an excellent anti-frosting character compared to pure staining steel. The surface morphology, chemical composition and wettability are characterized by means of SEM, XPS and water contact angle measurements. This method could provide a facile, low-cost and stable route to fabricate a large-area superhydrophobic surface with anti-frosting for application in various environments including in humid condition.

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

    Science.gov (United States)

    Kandula, M.

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    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 ?SN 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-15

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

  16. Robert Frost's Chicken Feathers and Other Lectures from the 1968 Augustana College NDEA English Institute. Augustana College Press Monograph Series No. 1.

    Science.gov (United States)

    Huseboe, Arthur R., Ed.

    The four lectures in this publication were composed with the common concern for making the study of high school English more effective and more delightful. Papers are (1) "Robert Frost's Chicken Feathers" by C. W. Geyer (discusses the influence of oral folklore and humor on Frost's poetry); (2) "Nature in Literature" by Gerhard T. Alexis; (3)…

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

    Science.gov (United States)

    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. PMID:26616985

  18. Enceladus' CO2 Frost comes from Near-Surface Gas Pockets

    Science.gov (United States)

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

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

  19. Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.

    Science.gov (United States)

    Salminen, J; Liiri, M; Haimi, J

    2002-09-01

    Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were analyzed. Soil respiration measurements from the microcosms appeared to be a sensitive parameter for testing community-level effects of chemicals in the soil with high organic matter content. An 84-day exposure had acute effects, long-term effects, delaying effects, and total recovery of community respiration. Direct negative and indirect positive effects of chemical contamination on the community of soil organisms were found. Responses to contamination of soil respiration rate and structure of the soil community were parallel. Addition of pentachlorophenol, 2-ethanolhexane, and Cu into the soil reduced frost resistance of the decomposer community. It was concluded that soil respiration monitoring of artificially contaminated soil microcosms seems to be a useful tool for testing community-level toxic effects of chemicals. PMID:12481864

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

    DEFF Research Database (Denmark)

    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...

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

    Science.gov (United States)

    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,…

  2. An elastoplastic model for the THM analysis of freezing soils

    OpenAIRE

    Satoshi, Nishimura; Gens Solé, Antonio; Olivella Pastallé, Sebastià; JARDINE, Richard

    2009-01-01

    By employing a combination of ice pressure, liquid pressure and total stress as state variables, a new thermoplastic constitutive model has been developed that encompasses frozen and unfrozen behaviour within a unified effective-stress-based framework. It has been incorporated into a fully coupled thermo-hydro-mechanical (THM) finite element formulation that considers freezing and thawing in water-saturated soils and applied to a large-scale pipeline frost heave test.

  3. Results of the radiological survey at 5 Frost Place, Albany, New York (AL184)

    International Nuclear Information System (INIS)

    A number of properties in the Albany/Colonie area have been identified as being potentially contaminated with uranium originating from the former National Lead Company's uranium forming plant in Colonie, New York. The property at 5 Frost Place in Albany, New York (AL184) was the subject of a radiological investigation initiated July 24, 1986. The residential property consists of a two-story frame house located on a rectangular lot. An asphalt driveway connects the house to the street. A diagram of the property showing the approximate boundaries and the 5-m grid network established for measurements outside the house is shown. The lot included in the radiological survey was /approximately/15 m wide by 31 m deep. A front view of the property is shown. 13 refs., 4 figs., 5 tabs

  4. Influence of Salt Stress on Growth and Frost Resistance of Three Winter Cereals

    Science.gov (United States)

    Matuszak-Slamani, Renata; Brzóstowicz, Aleksander

    2015-04-01

    This paper presents results of a study on the influence of 0-150 mmol NaCl dm-3 Hoagland solution on growth, chlorophyll content, photosynthesis and frost resistance of seedlings of three winter cereals: wheat - cv. Almari, rye - cv. Amilo, and triticale - cv. Tornado. Sodium chloride at 25 mmol dm-3 caused better growth of wheat shoots and roots, both of fresh and dry matter. Higher concentrations of NaCl in the medium decreased the biomass of the tested seedlings. The influence of NaCl on the chlorophyll content in the seedlings varied. The conductometry method showed that the resistance of the cell walls of wheat and rye to low temperature decreased in the presence of NaCl in the growth medium. Luminescence has shown that seedlings that grew in NaCl-containing medium indicated an impediment of electron flow at a lower temperature than the control plants.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    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.

  8. Effects of emissions from copper-nickel smelters on the frost hardiness of Finns sylvestris needles in the subarctic region.

    Science.gov (United States)

    Sutinen, M L; Raitio, H; Nivala, V; Ollikainen, R; Ritari, A

    1996-03-01

    It has been proposed that freezing injuries play an important role in the forest decline phenomenon. In this study, the effect of emissions from the copper-nickel smelters in Monchegorsk and Nikel-Zapolyarnyi in the Kola Peninsula, south-west Russia, on seasonal changes in the frost hardiness of Pinus sylvestris L. needles were studied. The frost hardiness of current-year needles during autumn, winter, spring and early summer in 1991-1993 was estimated by the electrolyte leakage method and by visual estimation of the proportion of damaged needles at nine sites in Finnish Lapland, at five sites in the vicinity of Monchegorsk and at two sites in Norway, in the vicinity of Nikel. The foliar S, Cu, and Ni concentrations also analysed. There were no significant differences at any time of the year between the frost hardiness of pine needles at the sites in Norway and Finnish Lapland. However, in the winter, the degree of visual damage at -45 °C, the temperature close to the lowest recorded temperature in this area, was slightly higher at the sites near to Nikel than at the sites in Finnish Lapland. In the Kola Peninsula the frost hardiness was consistently lower at the sites located 10 km to the south and 36 km to the south-west of Monchegorsk than at the other sites (48-110 km to the south-west). The differences were greatest in early June, 1991, when frost hardiness was -2 °C and -8°C at the sites closest to Monchegorsk. At the same time, the frost hardiness at the other sites was e.-20 °C. There were slight differences between years, but the trends were the same. A clearly increasing gradient in the S, Cu and Ni concentrations was observed on moving towards the emission point source at Monchegorsk. Highly elevated concentrations were found within 40 km of the smelter. The results suggest that air pollutants from the copper-nickel smelter have predisposed the pines to freezing injuries, rhus contributing to forest decline in the Kola Peninsula. PMID:26763646

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

    Directory of Open Access Journals (Sweden)

    Gustavo Ovando

    2005-03-01

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

  10. SHG & WHH - OVERCOMING SUSCEPTIBILITY

    Directory of Open Access Journals (Sweden)

    A. THOMAS WILLIAM

    2013-05-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Frost Resistance and Permeability of Cement Stabilized Gravel used as Filling Material for Pearl-Chain Bridges

    DEFF Research Database (Denmark)

    Lund, Mia Schou MØller; Hansen, Kurt Kielsgaard

    2014-01-01

    The Pearl-Chain Bridge Technology introduces a new innovative arch bridge solution which com-bines the statical advantages of an arch bridge with a minimum of traffic disturbance. The arch-shaped substructure is stabilized by a filling material, e.g. cement stabilized gravel, which should meet several requirements on its moisture properties. In this paper the frost resistance, the liquid water permeability and the water vapour permeability of cement stabilized gravel are examined for two different cement contents. It is found that a small increase in cement content from 4% to 5% increases the 28-days compressive strength from 6.2 MPa to 12.3 MPa. The frost resistance of cement stabilized gravel with 5% cement content is better than for cement stabilized gravel with 4% cement content. The liquid water permeability coefficient and the water vapour permeability coefficient are significantly higher for a cement content of 4% compared to 5%.

  13. Cryoprotectants are metabolic fuels during long term frost exposure in the earthworm Dendrobaena octaedra.

    DEFF Research Database (Denmark)

    C. Jørgensen, Sofia; Overgaard, Johannes; Holmstrup, Martin; Westh, Peter

    extracellular fluid. This study investigates if D. octaedra metabolizes its primary cryoprotectant as an energy source when frozen for longer periods. In this study D. octaedra were exposed to frost at 2 °C for 47 days. The results clearly demonstrate a gradual decrease in the level of glucose and...... simultaneously an accumulation of lactate, alanine and succinate as a result of the continuous anaerobic metabolism. Freeze mortality (~ 30%) did not increase with time suggesting that the accumulation of waste products were not toxic to the worms. Instead dead worms were always characterised by low glucose and...... worms. On the basis of metabolic rate measurements we calculated that the “average” worms would be able to survive for a total of 83 days before the glucose storage becomes exhausted. In conclusion, the present study suggests that the large accumulations of glucose during frost may be more important as...

  14. Simulated Frosts At Different Phenological Stages of the Potato Crop and Their Impact On Yields Cv Ccompis: Preliminary Studies

    International Nuclear Information System (INIS)

    The frost damages on the potato crop were simulated through an experiment in the Jiscuani community, in Southern Peru, Puno. Five levels of foliar damage (0, 25, 50, 75 and 100%) in different phenological stages were evaluated for their impact on tuber yield. The most significant phenological damages resulted at plant germination and at the early stolon formation, when foliar damage was higher than 50%. Moreover, the greatest effect on yield was caused at flowering stage (100 days after planting), recording reductions from 15 to 55 % at the different damage levels. The methodology for the frost simulation, cutting foliar sections according damage levels and making further rubbing on foliar area was apparently adequate. (author)

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

    Science.gov (United States)

    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.

  16. Autumn frost hardiness in Norway spruce plus tree progeny and trees of the local and transferred provenances in central Sweden.

    Science.gov (United States)

    Hannerz, Mats; Westin, Johan

    2005-09-01

    Reforestation with provenances from locations remote from the planting site (transferred provenances) or the progeny of trees of local provenances selected for superior form and vigor (plus trees) offer alternative means to increase yield over that obtained by the use of seed from unselected trees of the local provenance. Under Swedish conditions, Norway spruce (Picea abies (L.) Karst.) of certain transferred provenances generally has an advantage in productivity relative to the local provenance comparable to that of progeny of plus trees. The aim of this study was to explore the extent to which productivity gains achieved by provenance transfer or the use of plus tree progeny are associated with reductions in autumn frost hardiness, relative to that of trees of the local provenance. In a field trial with 19-year-old trees in central Sweden, bud hardiness was tested on four occasions during the autumn of 2002. Trees of the local provenance were compared with trees of a south Swedish provenance originating 3 degrees of latitude to the south, a Belarusian provenance and the progeny of plus trees of local origin. The Belarusian provenance was the least hardy and the local provenance the most hardy, with plus tree progeny and the south Swedish provenance being intermediate in hardiness. Both the Belarusian provenance and the plus tree progeny were significantly taller than trees of the other populations. Within provenances, tree height was negatively correlated with autumn frost hardiness. Among the plus tree progeny, however, no such correlation between tree height and autumn frost hardiness was found. It is concluded that although the gain in productivity achieved by provenance transfer from Belarus was comparable to that achieved by using the progeny of plus trees of the local provenance, the use of trees of the Belarus provenance involved an increased risk of autumn frost damage because of later hardening. PMID:15996961

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

    DEFF Research Database (Denmark)

    Wu, Min; Fridh, Katja; Johannesson, Björn; Geiker, Mette Rica

    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 measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of...

  18. Influence of minerals supply on the 'acute yellowing' syndrome as well as on growth increment, pigment balance, photosynthesis, frost hardiness, and sensitivity to ozone in Picea abies (L. ) Karst. Einfluss der Mineralstoffversorgung auf das Krankheitsbild 'akute Vergilbung', sowie auf Zuwachs, Pigmenthaushalt, Photosynthese, Frostresistenz und Empfindlichkeit gegenueber Ozon bei Picea abies (L. ) Karst

    Energy Technology Data Exchange (ETDEWEB)

    Hoepker, K.A.

    1989-07-19

    In this work the relevance of soil, soil-water balance (drought, waterlogging), tropospheric factors (air pollutants), and biotic factors (microorganisms) for the triggering of yellowing symptoms, biomass development, photosynthesis, the pigment balance, and frost hardiness in spruce was investigated. For this purpose a planting experiment was carried out where healthy tree-nursery material of different origin was planted in containers containing original soil from a yellowed spruce stand in the Bavarian Forest. Collaterally, the influence of minerals supply on ozone sensitivity in spruce was investigated in an ozone fumigation experiment. The influence of enhanced minerals supply on the 'acute yellowing' syndrome was additionally investigated in already ailing spruce material removed from its site. (MG).

  19. An Experimental Investigation On Minimum Compressive Strength Of Early Age Concrete To Prevent Frost Damage For Nuclear Power Plant Structures In Cold Climates

    International Nuclear Information System (INIS)

    Concrete undergoing early frost damage in cold weather will experience significant loss of not only strength, but also of permeability and durability. Accordingly, concrete codes like ACI-306R prescribe a minimum compressive strength and duration of curing to prevent frost damage at an early age and secure the quality of concrete. Such minimum compressive strength and duration of curing are mostly defined based on the strength development of concrete. However, concrete subjected to frost damage at early age may not show a consistent relationship between its strength and durability. Especially, since durability of concrete is of utmost importance in nuclear power plant structures, this relationship should be imperatively clarified. Therefore, this study verifies the feasibility of the minimum compressive strength specified in the codes like ACI-306R by evaluating the strength development and the durability preventing the frost damage of early age concrete for nuclear power plant. The results indicate that the value of 5 MPa specified by the concrete standards like ACI-306R as the minimum compressive strength to prevent the early frost damage is reasonable in terms of the strength development, but seems to be inappropriate in the viewpoint of the resistance to chloride ion penetration and freeze-thaw. Consequently, it is recommended to propose a minimum compressive strength preventing early frost damage in terms of not only the strength development, but also in terms of the durability to secure the quality of concrete for nuclear power plants in cold climates

  20. Cryoprotectants are metabolic fuels during long term frost exposure in the earthworm Dendrobaena octaedra.

    DEFF Research Database (Denmark)

    C. JØrgensen, Sofia; Overgaard, Johannes

    2008-01-01

    Ectothermic animals that live in the subarctic and temperate regions must have strategies to deal with periods of frost during winter. The earthworm Dendrobaena octaedra is a freeze tolerant species that accumulates large concentrations of the cryoprotectant glucose upon ice formation in the extracellular fluid. This study investigates if D. octaedra metabolizes its primary cryoprotectant as an energy source when frozen for longer periods. In this study D. octaedra were exposed to frost at 2 °C for 47 days. The results clearly demonstrate a gradual decrease in the level of glucose and simultaneously an accumulation of lactate, alanine and succinate as a result of the continuous anaerobic metabolism. Freeze mortality (~ 30%) did not increase with time suggesting that the accumulation of waste products were not toxic to the worms. Instead dead worms were always characterised by low glucose and glycogen levels indicating that depletion of fermentable resources was the primary cause of death. Calorimetric measurements of metabolic rate showed a 15-fold metabolic depression in frozen versus unfrozen worms and this reduction in metabolic rate is clearly of importance for long term survival of frozen worms. On the basis of metabolic rate measurements we calculated that the “average” worms would be able to survive for a total of 83 days before the glucose storage becomes exhausted. In conclusion, the present study suggests that the large accumulations of glucose during frost may be more important as anaerobic fuel source than as a cryoprotectant.

  1. Efficiency of frost-cracking processes through space and time: An example from the eastern Italian Alps

    Science.gov (United States)

    Savi, S.; Delunel, R.; Schlunegger, F.

    2015-03-01

    It is widely accepted that climate has a strong impact and exerts important feedbacks on erosional processes and sediment transport mechanisms. However, the extent at which climate influences erosion is still a matter of debate. In this paper we test whether frost-cracking processes and related temperature variations can influence the sediment production and surface erosion in a small catchment situated in the eastern Italian Alps. To this extent, we first present a geomorphic map of the region that we complement with published 10Be-based denudation rates. We then apply a preexisting heat-flow model in order to analyze the variations of the frost-cracking intensity (FCI) in the study area, which could have controlled the sediment production in the basin. Finally, we compare the model results with the pattern of denudation rates and Quaternary deposits in the geomorphic map. The model results, combined with field observations, mapping, and quantitative geomorphic analyses, reveal that frost-cracking processes have had a primary role in the production of sediment where the intensity of sediment supply has been dictated and limited by the combined effect of temperature variations and conditions of bedrock preservation. These results highlight the importance of a yet poorly understood process for the production of sediment in mountain areas.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-10-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Scientific Electronic Library Online (English)

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

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

  5. TuBaFrost 6: virtual microscopy in virtual tumour banking.

    Science.gov (United States)

    Teodorovic, I; Isabelle, M; Carbone, A; Passioukov, A; Lejeune, S; Jaminé, D; Therasse, P; Gloghini, A; Dinjens, W N M; Lam, K H; Oomen, M H A; Spatz, A; Ratcliffe, C; Knox, K; Mager, R; Kerr, D; Pezzella, F; van Damme, B; van de Vijver, M; van Boven, H; Morente, M M; Alonso, S; Kerjaschki, D; Pammer, J; Lopez-Guerrero, J A; Llombart Bosch, A; van Veen, E-B; Oosterhuis, J W; Riegman, P H J

    2006-12-01

    Many systems have already been designed and successfully used for sharing histology images over large distances, without transfer of the original glass slides. Rapid evolution was seen when digital images could be transferred over the Internet. Nowadays, sophisticated Virtual Microscope systems can be acquired, with the capability to quickly scan large batches of glass slides at high magnification and compress and store the large images on disc, which subsequently can be consulted through the Internet. The images are stored on an image server, which can give simple, easy to transfer pictures to the user specifying a certain magnification on any position in the scan. This offers new opportunities in histology review, overcoming the necessity of the dynamic telepathology systems to have compatible software systems and microscopes and in addition, an adequate connection of sufficient bandwidth. Consulting the images now only requires an Internet connection and a computer with a high quality monitor. A system of complete pathology review supporting bio-repositories is described, based on the implementation of this technique in the European Human Frozen Tumor Tissue Bank (TuBaFrost). PMID:17027253

  6. Influence of the female flowering environment on autumn frost-hardiness of Picea abies progenies.

    Science.gov (United States)

    Johnsen, O; Skrøppa, T; Junttila, O; Dæhlen, O G

    1996-05-01

    Two experiments were designed to test possible effects of photoperiod and temperature during microsporogensis to anthesis on early autumn frost-hardiness of Picea abies progenies. Pollen lots were produced in phytotron rooms and used in crosses in a seed orchard. No biologically important differences in progeny performance were evident either between high and low temperature or between long and short-day treatments, and no significant interaction between photoperiod and temperature was found. In a third experiment, however, an effect of the environment during female flowering was obtained. Crosses performed in early spring (March) inside a heated greenhouse (short day, high temperature) produced progenies which were less hardy than their full-sibs reproduced from crosses indoors (long day, high temperature) and outdoors (long day, low temperature) in May. The most hardy siblings originated from the late-spring outdoor crosses. These results indicate that some stages in reproduction during female flowering, such as female meiosis, pollen tube growth, syngamy, early embryogenesis and embryo competition, may be sensitive to temperature and/or photoperiodic signals which can be transmitted to the progeny. We suspect that the altered performance of the progenies could be due to an activation of a regulatory mechanism affecting the expression of genes controlling adaptive traits. Both the present and earlier results have implications for the genetic interpretation of provenance differences in Norway spruce. PMID:24166543

  7. TuBaFrost 4: access rules and incentives for a European tumour bank.

    Science.gov (United States)

    Lopez-Guerrero, J A; Riegman, P H J; Oosterhuis, J W; Lam, K H; Oomen, M H A; Spatz, A; Ratcliffe, C; Knox, K; Mager, R; Kerr, D; Pezzella, F; van Damme, B; van de Vijver, M; van Boven, H; Morente, M M; Alonso, S; Kerjaschki, D; Pammer, J; Carbone, A; Gloghini, A; Teodorovic, I; Isabelle, M; Passioukov, A; Lejeune, S; Therasse, P; van Veen, E-B; Dinjens, W N M; Llombart-Bosch, A

    2006-11-01

    When designing infrastructure for a networked virtual tumour bank (samples remain at the collector institutes and sample data are collected in a searchable central database), it is apparent that this can only function properly after developing an adequate set of rules for use and access. These rules must include sufficient incentives for the tissue sample collectors to remain active within the network and maintain sufficient sample levels in the local bank. These requirements resulted in a key TuBaFrost rule, stating that the custodianship of the samples remains under the authority of the local collector. As a consequence, the samples and the decision to issue the samples to a requestor are not transferred to a large organisation but instead remain with the collector, thus allowing autonomous negotiation between collector and requestor, potential co-authorship in publications or compensation for collection and processing costs. Furthermore, it realises a streamlined cost effective network, ensuring tissue visibility and accessibility thereby improving the availability of large amounts of samples of highly specific or rare tumour types as well as providing contact opportunities for collaboration between scientists with cutting edge technology and tissue collectors. With this general purpose in mind, the rules and responsibilities for collectors, requestors and central office were generated. PMID:17027256

  8. Penetration of chlorides in hardened concrete during frost salt scaling cycles

    Directory of Open Access Journals (Sweden)

    Moral N.

    2010-06-01

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

  9. Frost-free North Polar Layers in the Good Old Summertime

    Science.gov (United States)

    2006-01-01

    17 October 2006 The middle portion of the northern summer season is the ideal time of year to capture relatively dust- and haze-free views of martian north polar terrain. This year, much more of the north polar cap has sublimed away than has been evident in previous northern summers going back to 1999, when Mars Global Surveyor (MGS) began the Mapping Phase of the mission. This MGS Mars Orbiter Camera (MOC) image shows a nearly ice-free view of layers exposed by erosion in the north polar region. The light-toned patches are remnants of water ice frost. The layers are generally considered by the Mars scientific community to be record of past depositions of ice and dust. This picture is located near 82.5oN, 118.6oW, and covers an area about 3 km by 10 km (1.9 by 6.2 miles). Sunlight illuminates the scene from the upper left; the image was acquired on 22 September 2006.

  10. Use of Gibberellins to Improve Fruit Set in Pears After Frost Damage

    Directory of Open Access Journals (Sweden)

    George Ouma

    2008-01-01

    Full Text Available The objectives of this study were to investigate the effect of applied bioregulators on fruit set after this frost in April 2002, growth, yield and the incidence of Pseudomonas syringae and the understanding of the underlying mechanisms of fruit set by applying bioregulators shortly after full bloom at the Klein-Altendorf experimental station near Bonn, Germany with the following results. The best fruit set was achieved with both GA3 and GA3 plus 0.5l GA4+7 sprayed at 12 mL ha-1 which increased initial fruit set by 78 and 77%, respectively as compared to unsprayed control with 32% while it was GA3 (105% followed by the combination of GA3, Promalin and Azolon (100% after June drop. The second-best fruit set was in GA3 plus 0.25l of GA4+7 and Azolon sprayed at 12 mL ha-1. Azolon reduced fruit set before and after June drop. Repeat applications of the treatments did not generally improve the results of fruit set after June drop. It is concluded that GA3 or combined with GA4+7, successfully improved fruit set, shoot growth, reduced the incidence of Pseudomonas syringae and rescued the yield showing that the mechanism is via development of parthenocarpic fruit.

  11. Thermodynamic and fracture mechanical processes in the context of frost wedging in ice shelves

    Science.gov (United States)

    Plate, Carolin; Müller, Ralf; Humbert, Angelika; Gross, Dietmar

    2015-04-01

    Ice shelves, the link between ice shields or glaciers and the ocean are sensitive elements of the polar environment. The ongoing break up and disintegration of huge ice shelf parts or entire ice shelf demands for an explication of the underlying processes. The first analyses of crack growth and break up events in ice shelves date back to more than half a century. Nevertheless, the mechanisms that trigger and influence the collapse of whole ice shelf parts are not yet fully understood. Popular presumptions link ice shelf disintegration to surface meltwater and hydro fracturing, explaining break up events in warm polar seasons. Fracture events during colder seasons are possibly triggered by more complex mechanisms. A well-documented break up event at the Wilkins Ice Shelf bridge inspires the possibility of frost wedging as disintegration cause. The present study shows a two-dimensional thermo-dynamical model simulating the growth of an ice lid in a water-filled crevasse for measured surface temperatures. The influence of the crevasse geometry and the ice shelf temperature are shown. The resulting lid thickness is then used for the linear elastic fracture mechanical analysis. The maximum crack depth is estimated by comparing the computed stress intensity factors to critical values KIc obtained from literature. The thermodynamic as well as the fracture mechanical simulation are performed using the commercial finite element code COMSOL. The computation of KI follows in post processing routines in MATLAB exploiting the benefits of the concept of configurational forces.

  12. Cryosorption of helium on argon frost TFTR [Tokamak Fusion Test Reactor] neutral beamlines

    International Nuclear Information System (INIS)

    Helium pumping on argon frost has been investigated on TFTR neutral beam injectors and shown to be viable for limited helium beam operation. Maximum pumping speeds are ? 25% less than those measured for pumping of deuterium. Helium pumping efficiency is low, > 20 argon atoms are required to pump each helium atom. Adsorption isotherms are exponential and exhibit a two-fold increase in adsorption capacity as the cryopanel temperature is reduced from 4.3 K to 3.7 K. Pumping speed was found to be independent of cryopanel temperature over the temperature range studied. After pumping a total of 2000 torr-l of helium, the beamline base pressure rose to 2x10-5 torr from an initial value of 10-8 torr. Accompanying this three order of magnitude increase in pressure was a modest 40% decrease in pumping speed. The introduction of 168 torr-l of deuterium prior to helium injection reduced the pumping speed by a factor of two with no decrease in adsorption capacity. 29 refs., 7 figs

  13. Soil physical properties affecting soil erosion in tropical soils

    International Nuclear Information System (INIS)

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

  14. Past and projected future changes in snowpack and soil frost at the Hubbard Brook Experimental Forest, New Hampshire, USA

    Science.gov (United States)

    Long-term data from the Hubbard Brook Experimental Forest in New Hampshire show that air temperature has increased by about 1 °C over the last half century. The warmer climate has caused significant declines in snow depth, snow water equivalent, and snow cover duration. Paradoxically, it has been su...

  15. Effects of Initial Nematode Density on Population Dynamics of Globodera rostochiensis on Resistant and Susceptible Potatoes

    OpenAIRE

    LaMondia, J.A.; Brodie, B. B.

    1986-01-01

    The influence of resistant and susceptible potato cultivars on Globodera rostochiensis population density changes was studied at different nematode inoculum levels (Pi) in the greenhouse and field. Soil in which one susceptible and two resistant cultivars were grown and fallow soil in pots was infested with cysts to result in densities of 0.04-75 eggs/cm³ soil. A resistant cultivar was grown in an infested field with Pi of 0.7-16.7 eggs/cm³ soil. Pi was positively correlated with decline of s...

  16. Nonlinear apparent susceptibility mapping

    Science.gov (United States)

    Zunino, A.; Benvenuto, F.; Armadillo, E.; Bertero, M.; Bozzo, E.

    2009-04-01

    Digital enhancement of maps is one of the most useful tool to drive the interpretation of potential fields data. Among the many techniques available in literature, apparent susceptibility mapping provides a good qualitative picture of the actual magnetic susceptibility distribution. Essentially the approach consists of an inversion based on the following assumptions. First, there is no remanent magnetization. Second, the subsoil is modeled as a set of vertical prisms with the top at a given depth and infinitely extended downward. Because the standard magnetometers commonly employed in surveys measure the modulus of the total field, which components depend on the susceptibility by means of affine operators, the relation with respect to susceptibility results nonlinear. We developed a new algorithm based on a nonlinear forward model that is a better approximation of the real case than the standard linearized one. In fact, there are some significant drawbacks in the case of linearized inversion, decreasing the resolution power and creating some artifacts in the solution. So we solve the inverse problem corresponding to the completely nonlinear forward model. The inverse problem is transformed in a minimization of a functional derived from the maximum likelihood principle. Minimization is carried on by an iterative scaled and projected gradient algorithm that improves the speed of convergence and includes a line search for the step-length parameter reducing considerably the number of iterations required. Moreover we impose the solution to be nonsmooth applying a Total-Variation--like regularization. This edge--preserving regularization allows the solution to have a blocky structure, as often occurs in real cases. We first tested the method on a synthetic case, simulating a distribution of susceptibility in the subsurface and then inverting the calculated data having previously added some noise. Then we applied the described methodology to a real dataset acquired in East Antarctica during the 2003-2004 WIBEM campaign. The survey covers the the western flank of the Wilkes Subglacial Basin, a major morphological feature recognized in the hinterland of the Transantarctic Mountains. Evidences from the enhanced aeromagnetic anomaly maps show a strong structural control on the western side of the basin, suggesting that the previously hypothesized purely flexural origin for the basin is unlikely.

  17. Soil management practices for sustainable crop production

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-05-01

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

  19. Teleconnection patterns and Rossby wave propagation associated to generalized frosts over southern South America

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Gabriela V.; Ambrizzi, Tercio [University of Sao Paulo, Institute of Astronomy, Geophysics and Atmospheric Sciences, Sao Paulo (Brazil)

    2007-11-15

    Based on previous observational studies of the mean atmospheric circulation leading to generalized frosts (GF) in central Southern South America, it is possible to establish a hypothesis that specific large scale patterns are associated to the frequency of occurrence of these events through the propagation of Rossby waves remotely excited. This hypothesis is tested here through a teleconnection analysis for austral winters which present an extreme frequency of occurrence of GF in southeastern South America, particularly over the Wet Pampa area in Argentina. Rossby wave propagation regions are identified for two basic states given by the composition of winters with maximum and minimum frequency of GF occurrence, during the 1961-1990 period. The stationary wavenumber K{sub s} indicates the regions where the Rossby wave propagation is permitted and those where it will be inhibited (K{sub s} = 0), highlighting the importance of the jets as waveguides. Nevertheless, differences exist between both basic states analyzed. These differences indicate that the locations for wave generation and its later evolution are conditioned by the basic state. Results are validated through a baroclinic model, which simulates the Rossby wave patterns responsible for the teleconnection. Numerical experiments confirm that the principal wave activity takes place inside the subtropical and polar jets. In particular, for the basic state with maximum frequency of GF occurrence, the wave trains propagating inside the subtropical and polar waveguides merge just before entering the continent, as shown by the observations prior to the occurrence of GF events. This configuration favors the development of an intense south wind anomaly with large meridional extension which results in the intensification of anticyclonic circulation in southern South America. A conceptual model is presented to summarise all these results. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  1. Detection of Soil Freeze/thaw Processes with Smos

    Science.gov (United States)

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

    2012-12-01

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

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

    Directory of Open Access Journals (Sweden)

    S.V. Chuduk

    2011-01-01

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

  3. Spatial distribution and temporal variation of the winter wheat late frost disaster in Henan, China

    Science.gov (United States)

    Zhang, Xuefen; Zheng, Youfei; Wang, Chunyi; Chen, Huailiang; Ren, Zhenhe; Zou, Chunhui

    2011-04-01

    The winter wheat late frost disaster (WFD) occurs mainly in the Yellow and Huaihe River area, of which Henan Province covers the most part. Henan is the major area of wheat production in China, but it is severely hit by the WFD. In this study, we construct a WFD index based on the minimum temperature and the winter wheat development period (WDP). The WFD degrees and days at 30 agrometeorological stations in Henan Province during the period of 1981-2004 are calculated. For the large-scale temporal variation analysis of WFD, the 24-yr WDP observation series is relatively short, so it is expanded by using the relation between the turning green date of winter wheat and the 5-day running mean temperature and that between the stem elongation phase and the effective cumulative temperature above a critical value of 2.5°C. The WFD data are also expanded for the last 50 years and are analyzed by using the empirical orthogonal function (EOF) and the Morlet wavelet methods. Characteristics in the spatial distribution and temporal variation of WFD are revealed. The results show that the frequency of WFD is generally high, exceeding 40% in parts of Henan, and exhibits a rising trend in the period of 1970-1990. The variation trend of WFD degrees is similar to that of WFD days, and the areas with higher WFD degrees coincide the areas with more WFD days. Moreover, the WFD degree has a greater impact on the winter wheat yield than the WFD days. The areas with high WFD degrees lie in the southeast and southwest of Henan, and the areas with low WFD degrees lie in the south of the Huaihe River and parts of western Henan. Temporal variations of the first and second EOF modes of the WFD degree display 16- and quasi-22-yr periodicities, respectively. The areas of high (low) WFD frequency are distributed in the northern Henan and the southwest border of Henan (the northeast Henan and the middle part of southwest Henan). The temporal variation of the first (second) EOF mode of WFD days exhibits a periodicity (periodicities) of quasi-4 yr (quasi-3 and quasi-6-7 yr).

  4. Fracture Mechanical Analysis of Frost Wedging in Ice Shelves as Break-Up Mechanism

    Science.gov (United States)

    Plate, Carolin; Humbert, Angelika; Gross, Dietmar; Müller, Ralf

    2013-04-01

    Disintegration events in ice shelves have been the subject of extensive investigations in the past years, however comprehensive explanations applicable to a majority of events are still missing. A popular assumption made by Scambos et al. (2000) [1] links disintegration events to a general thinning of the ice shelf in conjunction with growing melt-water ponds leading to hydro fractures. This explanation seems reasonable for break-up events that happened in Antarctic summers. Large parts of the Wilkins Ice Shelf, however broke-up in fall and winter periods. Therefore, the aim of the present study is to analyse the possibility of frost wedging of water filled surface crevasses in an ice shelf as a source of break-up events. Configurational forces are used to assess crack criticality. The simulations are performed on a 2-dimensional single crack with a mode-I type load, body forces and additional crack-face pressure due to freezing of the water. Depth-dependent density profiles are considered. The relevant parameters, Young's modulus, Poisson's ratio and external loading are obtained from literature, remote sensing data analysis and modelling of the ice dynamics. The investigation is performed using the finite element software COMSOL. The simulations show that in comparison to water filled crevasses without ice, thin layers of frozen water may lead to a decreasing criticality at the crack tip as long as the ice 'bridge' is allowed to take tensile loads. An increasing crack criticality can be seen for thicker layers of ice. The results are compared to findings from previous finite element analyses of dry and water filled cracks as presented in Plate et al. (2012) [2]. [1] Scambos, T., Hulbe, C., Fahnestock, M., & Bohlander, J. (2000). The link between climate warming and break-up of ice shelves in the Antarctic Peninsula. Journal of Glaciology, 46(154), 516-530. [2] Plate, C., Müller, R., Humbert, A., & Gross, D. (2012). Evaluation of the criticality of cracks in ice shelves using finite element simulations. The Cryosphere, 6(5), 973-984.

  5. The impact of soil compaction and freezing-thawing cycles on soil structure and yield in Mollisol region of China

    Science.gov (United States)

    Wang, Enheng; Zhao, Yusen; Chen, Xiangwei

    2015-04-01

    Agricultural machinery tillage and alternating freezing and thawing are two critical factors associated with soil structure change and accelerates soil erosion in the black soil region of Northeast China. Combining practical machinery operation and natural freeze-thaw cycles with artificial machinery compaction in the field and artificial freeze-thaw cycles in the lab, the plus and minus benefits of machinery tillage, characterization of seasonal freeze-thaw cycles, and their effects on soil structure and yield were studied. Firstly?the effects of machinery type and antecedent water content on soil structure and soil available nutrient were investigated by measuring soil bulk density, soil strength, soil porosity, soil aggregate distribution and stability, and three soil phases. The results showed that: Machinery tillage had positive and negative influence on soil structure, soil in top cultivated layer can be loosened and ameliorated however the subsoil accumulation of compaction was resulted. For heavy and medium machinery, subsoil compaction formed in the soil depth of 41~60cm and 31~40cm, respectively; however during the soil depth of 17.5~30cm under medium machinery operation there was a new plow pan produced because of the depth difference between harvesting and subsoiling. Antecedent water content had a significant effect on soil structure under machinery operations. Higher water antecedent resulted in deeper subsoil compaction at 40cm?which was deeper by 10cm than lower water content and soil compaction accumulation occurred at the first pass under higher water content condition. Besides water content and bulk density, soil organic matter is another key factor for affecting compressive-resilient performance of tillage soil. Secondly, based on the soils sampled from fields of the black soil region, the effects of freeze-thaw cycles on soil structure at different soil depths (0 -- 40 cm, 40 -- 80 cm, 120 -- 160 cm) and size scales (field core sampling scale of seasonal freeze-thaw cycles, computerized tomography [CT] scale of artificial freeze-thaw cycles, and scanning electron microscope [SEM] scale of artificial freeze-thaw cycles) were studied. The results showed that: At three scale of seasonal freeze-thaw cycles, soil structure of sub soil (40 -- 80 cm) changed more significantly comparing to the top soil and underling soil, this may be contributed by the higher clay content in soil. Soil compaction accelerated and subsoiling relieved dynamics condition of seasonal freezing and thawing process, resulting to a deeper and a lower frost depth, respectively. Soybean yield was not changed by compaction or subsoiling, or their interaction effects; however, interestingly hundred-gain weight of soybean increased after appropriate compactions but decreased when subsoiling was implemented on compacted soil.

  6. Topological Susceptibility from Slabs

    CERN Document Server

    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.

  7. Susceptibility to anchoring effects

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Dębicki R.

    2001-03-01

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

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

    DEFF Research Database (Denmark)

    Wu, Min; Fridh, Katja

    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 measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of cement pastes, frost damage probably took place and it changed the pore connectivity while it had limited effect on changing the interior size distribution of the meso-pores. The analysis of the freezing and melting behavior of the pore liquid of cement based materials is complicated by the presence of ions. The freezing and melting behavior of the pore solution of cement paste samples preconditioned in either a small amount or a big amount of saturated limewater was compared. The results suggest that either the preconditioning in a big amount of limewater does not change the ionic concentration of the pore solution very much or the possible leaching of ions from cement hydrates during the preconditioning has limited influence on the freezing and melting behavior of the pore solution in the studied cement paste samples.

  10. Experimental analysis on frosting characteristic of SK-type finned refrigerating heat exchanger with large-diameter circular holes

    International Nuclear Information System (INIS)

    This paper presents the construction of both a plane fin-and-tube heat exchanger and a SK-type fin-and-tube heat exchanger. Based on plane fin-and-tube heat exchanger, comparative industrial prototype experiments of SK-type fin-and-tube heat exchanger energy efficiency performance were carried out in the artificial climate chamber. Test results confirmed several findings: when the amount of the refrigerant charged is the same and face velocity u = 3.75 m s−1, SK-type fin-and-tube heat exchanger refrigeration capacity increases by an average of 9.13%; energy consumption reduces by an average of 11.25%, coefficient of performance (COP) of heat exchanger increases by an average of 22.65% with continuous operation during the first 2 h. Also, when the operation time exceeds 2 h, the COP of both types of heat exchangers are both less than 0.6, illustrating that under frost conditions, the defrost interval should not be too long, otherwise energy consumption may sharply spike. - Highlights: •The large holes of SK-type induced the generation of turbulence flow. •The refrigeration capacity and COP of SK-type exceeds that of plane one. •The SK-type fin-and-tube heat exchanger is a new kind of heat transfer equipment. •The defrost interval should not exceed 2 h under frost conditions

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

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

  13. Algebraic modeling and thermodynamic design of fan-supplied tube-fin evaporators running under frosting conditions

    International Nuclear Information System (INIS)

    In this study, the method of entropy generation minimization (i.e., design aimed at facilitating both heat, mass and fluid flows) is used to assess the evaporator design (aspect ratio and fin density) considering the thermodynamic losses due to heat and mass transfer, and viscous flow processes. A fully algebraic model was put forward to simulate the thermal-hydraulic behavior of tube-fin evaporator coils running under frosting conditions. The model predictions were validated against experimental data, showing a good agreement between calculated and measured counterparts. The optimization exercise has pointed out that high aspect ratio heat exchanger designs lead to lower entropy generation in cases of fixed cooling capacity and air flow rate constrained by the characteristic curve of the fan. - Highlights: • An algebraic model for frost accumulation on tube-fin heat exchangers was advanced. • Model predictions for cooling capacity and air flow rate were compared with experimental data, with errors within ±5% band. • Minimum entropy generation criterion was used to optimize the evaporator geometry. • Thermodynamic analysis led to slender designs for fixed cooling capacity and fan characteristics

  14. Performance investigation of a novel frost-free air-source heat pump water heater combined with energy storage and dehumidification

    International Nuclear Information System (INIS)

    Highlights: • Experiments are carried out to investigate a novel frost-free ASHPWH system. • Dynamic characteristics of the system are studied at different ambient conditions. • Test results confirm the expected potential to control the frost-free process. • The COP increased 17.9% and 3.4% respectively in comparison with RCD at ?3 °C and 3 °C. - Abstract: Air-source heat pump (ASHP) often operates with substantial frost formation on the outdoor heat exchanger at low ambient temperature in winter, it insulates the finned surface and also reduces heat transfer rate, leading to performance degradation or even shutdown of ASHP systems. Although several defrosting methods have been reported, the frosting and defrosting processes reduced energy efficiency and resulted in, in some cases, heat pump breakdown. To solve this problem, a novel frost-free air-source heat pump water heater (ASHPWH) system has been developed, which coupled with an extra heat exchanger coated by a solid desiccant (EHECSD) with an energy storage device (ESD). Based on the previous studies, a further analysis and comprehensive research on the novel frost-free ASHPWH system is presented in this paper. The dynamic characteristics of the novel system are investigated experimentally in different ambient conditions. An experimental setup and experimental procedures are described in detail. Thereafter, the dehumidification efficiency and regeneration efficiency of EHECSD, suction and discharge pressures of the compressor, the temperature of PCM are evaluated during the heating and regeneration modes respectively. Results indicate that the system can keep the evaporator frost-free for 32, 34, 36 min during heating mode at the ambient temperatures of ?3 °C, 0 °C and 3 °C and 85% RH. Compared with the reverse-cycle defrosting (RCD), COP of the frost-free ASHPWH are 17.9% and 3.4% higher at the ambient temperature of ?3 °C and 3 °C respectively. With this innovative technology, it has been proved that the new system can realize continuous heating and excellent performance at a low ambient temperature

  15. Magnetic susceptibility: a proxy method of estimating increased pollution

    International Nuclear Information System (INIS)

    A need for rapid and inexpensive (proxy) methods of outlining areas exposed to increased pollution by atmospheric particulates of industrial origin caused scientists in various fields to use and validate different non-traditional (or non-chemical) techniques. Among them, soil magnetometry seems to be a suitable tool. This method is based on the knowledge that ferrimagnetic particles, namely magnetite, are produced from pyrite during combustion of fossil fuel. Besides the combustion processes, magnetic particles can also originate from road traffic, for example, or can be included in various waste-water outlets. In our study we examine the magnetic susceptibility as a convenient measure of determining the concentration of (ferri) magnetic minerals by rapid and non-destructive means. We used for measure KLY-2 Kappabridge. Concentration of ferrimagnetic minerals in different soils is linked to pollution sources. Higher χ values were observed in soils on the territory in Istebne (47383x10-6 SI ). The susceptibility anomaly may be caused by particular geological circumstances and can be related to high content of ferromagnetic minerals in the host rocks. Positive correlation of magnetic susceptibility are conditioned by industrial contamination mainly by metal working factories and by traffic. The proposed method can be successfully applied in determining heavy metal pollution of soils on the city territories. (authors)

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

    Scientific Electronic Library Online (English)

    G. V., MÜLLER; T., AMBRIZZI.

    2010-01-01

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

  17. In Field Monitoring of Potential Detrimental Effects of Biofuels Production on Soil Quality

    Science.gov (United States)

    Soil organic carbon (SOC) content is recognized as a soil quality indicator that is susceptible to degradation with tillage and with biomass removal from the soil surface. In addition to reported benefits of leaving crop residue on the soil surface in preventing soil erosion, providing plant nutrien...

  18. Magnetic susceptibility from electron holes

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2013-07-01

    Full Text Available A recent theory of magnetic field amplification in electron holes is extended to derive the magnetic susceptibility of an electron-hole gas propagating in a magnetic flux tube along the ambient magnetic field. It is shown that the hole gas behaves diamagnetic adding some small amount to the well-known Landau susceptibility in the hole-carrying volume.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Spin susceptibility in superconductors

    International Nuclear Information System (INIS)

    The wave-vector-dependent spin susceptibility chi(q) of a superconductor in one, two, and three dimensions is calculated numerically. These calculations show that for large qapprox.k/sub F/, where k/sub F/ is the Fermi momentum, chi(q) is essentially the same as that in the normal state, indicating that for distances r0 (xi0 the coherence length), Ruderman-Kittel-Kasuya-Yosida coupling between magnetic atoms is essentially unchanged by superconductivity of the system. In one and two dimensions we find a reduction in chi(q) at very small q, whose structure affects any possible cryptomagnetic order of the type suggested by Anderson and Suhl for the case of three dimensions. In three dimensions our calculation verifies the validity of the approximate chi(q) of Anderson and Suhl in the appropriate q region. For small q, chi(q) shows a much stronger dependence on q for lower dimensions than in the three-dimensional case, which has a bearing on the range of magnetic ordering, and may be relevant to rare-earth materials with Fermi-surface ''nesting.''

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

    Science.gov (United States)

    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 frosts (until June). In the Loire Valley area, frost is rare as early as April. The combined effects of the continentality and the topographical features of the Upper Rhine Graben explain the hard frosts in early spring at Colmar, but also higher temperature at Colmar than at Reims from April. The Champagne area is the most exposed to frost-producing North-Westerly and Northerly atmospheric circulations in late spring (e.g. on May the 5th, 1996: minimum temperature of -1°C at Reims / Champagne and +3.8°C at Colmar). The identification and frequency of atmospheric circulation patterns causing spring frost (daily minimum temperature below 0°C) and hard frost (daily minimum temperature below -5°C) were carried out using the objective computational version of the 29-type Hess and Brezowsky Grosswetterlagen system of classifying European synoptic regimes (James, 2007). Minimum temperature data were got from the Meteo-France database (Climathèque), for the spring months (March, April and May) and for the period 1960-2007, at the weather stations of Saumur (Loire Valley), Reims (Champagne), Dijon (Burgundy) and Colmar (Alsace). More than 40% of the frost days occurring at all weather stations were associated with North-Westerly and Northerly circulation types, 27% with North-Easterly and Easterly circulation types and 16% with a main high or low pressure area over central Europe. More precisely, the cyclonic circulations involving a northerly flow over western Europe (15.6%) and Anticyclonic North-Easterly circulations (9,3%) are the most frequent circulations types associated with frost days. These circulation types bring air-masses favourable to radiation cooling, under clear sky and light wind, or cold air-masses from northern or eastern Europe causing advection cooling. The stations of eastern France can be subjected to frost events even during Westerly or Southerly circulations, while frost occurrence in the Saumur area requires a higher ratio of North-Easterly and Easterly circulations (10% at Colmar ; 37% at Saumur). Because of the location of Saumur in west

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. 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?

    Science.gov (United States)

    Pucha?ka, Rados?aw; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; D?browski, Henryk P.

    2015-11-01

    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.

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

    International Nuclear Information System (INIS)

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

  5. Influence of wind velocity fluctuation on air temperature difference between the fan and ground levels and the effect of frost protective fan operation

    International Nuclear Information System (INIS)

    We invested the influence of wind velocity fluctuation on air temperature difference between the fan (4.8 m) and ground levels (0.5 m) and the effect of frost protective fan operation in order to develop a new method to reduce electricity consumption due to frost protective fan operation. The results of the investigations are summarized as follows: (1) Air temperature difference between the fan (4.8 m) and ground levels (0.5 m) was decreased following an increase in wind velocity, and the difference was less than 1°C for a wind velocity more than 3.0 m/s at a height of 6.5 m. (2) When the wind velocity was more than 2-3 m/s, there was hardly any increase in the temperature of the leaves. In contrast, when the wind velocity was less than 2-3 m/s, an increase in the temperature of the leaves was observed. Based on these results, it is possible that when the wind velocity is greater than 2-3 m, it prevents thermal inversion. Therefore, there would be no warmer air for the frost protective fan to return to the tea plants and the air turbulence produced by the frost protective fan would not reach the plants under the windy condition

  6. Frost Grape Polysaccharide (FGP), an emulsion-forming arabinogalactan gum from the stems of native North American grape species Vitis riparia Michx

    Science.gov (United States)

    A new arabinogalactan is described that is produced in large quantity from the cut stems of the North American grape species Vitis riparia (Frost grape). The sugar composition consists of L-arabinofuranose (L-Araf, 55.2 %) and D-galactopyranose (D-Galp 30.1%), with smaller components of D-xylose (11...

  7. Identifying indicators of soil suppressiveness to fungal diseases

    OpenAIRE

    Siegel, Katarzyna; Aime, Sébastien; Chapelle, Emilie; Edel Hermann, Veronique; Raaijmakers, Jos M.; LEMANCEAU Philippe; Steinberg, Christian

    2013-01-01

    Soils suppressive to soil-borne diseases are defined by a low disease incidence in spite of the presence of a virulent pathogen and a susceptible plant. In many cases, the inhibition of the disease development relies on the activity of the resident soil microbiome. To identify taxonomic microbial indicators linked to the suppressiveness phenotype of soils, culture independent-based methods have been employed to analyse and compare microbial dynamics in two different soils suppressive to eithe...

  8. Mapping of ferrimagnetic susceptibility for screening of fly ash deposition

    Science.gov (United States)

    Fürst, C.; Zirlewagen, D.; Makeschin, F.

    2012-04-01

    The proposed presentation introduces a case study in the Dübener Heide, industrial triangle Leipzig-Halle-Bitterfeld in Saxony, whose purpose was (a) to assess the current fly ash load in forest soils and (b) to test if ferrimagnetic susceptibility can be used for a fast and cost efficient screening of deposited elements. Ferrimagnetic susceptibility was mapped in a raster of 1x1 km2 and correlated with selected nutrients metals, heavy metals and Black Carbon. The predictive value of ferromagnetic magnetic susceptibility was tested on the basis of linear regression models. The correlation between ferrimagnetic susceptibility, base saturation and the contents in Ca, Mg, Fe, Al and Cd (humus layers) was comparably high. The correlation with the content in Mn was weaker and the correlation with Black Carbon (humus layers) showed no clear trend. Linear regression based models with sufficient precision could be found for Ca, Mg and Mn, with lower precision for Cd and Black Carbon. No prediction was possible for Fe and Al. Furthermore, multiple-regionalization techniques were used to model the spatial variation of historical fly ash deposition. This includes an analysis, which environmental parameters are most important for the spatial model. The multiple regression based modeling of the spatial variation of fly ash deposition was possible with a very high precision. A slightly differing set of model parameters was selected for different depth levels in the humus layer and mineral soil, comprising topographical and soil parameters and to a much lesser extend stand parameters. In conclusion, the usability of the proxy indicator ferrimagnetic susceptibility for screening of the deposited elements was proved.

  9. Numerical study of the pressure drop in a plain fin-and-circular tube heat exchanger under frost condition

    International Nuclear Information System (INIS)

    Full text: Three-dimensional computational fluid dynamics (CFD) simulations are carried out to study the pressure drop behavior in a plain fin-and-four staggered layout and circular tube rows for different fin pitches under frost conditions using FLUENT 6.3 CFD code. Models geometry is created and meshed using GAMBIT 2.3. Fluid flow and heat transfer are simulated and results calculated using (Transitional SST k-omega) turbulence model, with steady-state solver. Model validation is carried out by comparing the pressure drop of a simulated case with experimental results from the literature. It was found that Fluent 6.3 software has been sufficient for simulating the flow characteristics in tube-fin heat exchangers. (author)

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    humans eating under-cooked pork meat harbouring T. solium metacestodes. Deterministic models of each scenario were first run, followed by stochastic versions of the models to assess the likelihood of infection elimination in the small population modelled. The effects of three groups of interventions were...... investigated using the model: (i) interventions affecting the transmission parameters such as use of latrines, meat inspection, and cooking habits; (ii) routine interventions including rapid detection and treatment of human carriers or pig vaccination; and (iii) treatment interventions of either humans or pigs......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...

  11. FLOOD SUSCEPTIBILITY ASSESSMENT IN THE NIRAJ BASIN

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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 ?g N m?2 h?1, the EC method is a good alternative to measure N2O and CO2 fluxes at ecosystem scale, thereby minimizing problems with chamber enclosures and spatial representativeness of the measurements.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-12-01

    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.

  16. Soil erodibility for water erosion: A perspective and Chinese experiences

    Science.gov (United States)

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

  17. Topological susceptibility from the overlap

    DEFF Research Database (Denmark)

    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. 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 resul...

  18. Ancestral susceptibility to colorectal cancer.

    Czech Academy of Sciences Publication Activity Database

    Huhn, S.; Pardini, Barbara; Naccarati, Alessio; Vodi?ka, Pavel (ed.); Hemminki, K.; Försti, A.

    2012-01-01

    Ro?. 27, ?. 2 (2012), s. 197-204. ISSN 0267-8357 R&D Projects: GA ?R GA310/07/1430; GA ?R GAP304/10/1286 Grant ostatní: EU FP7(XE) HEALTH-F4-2007-200767 Institutional research plan: CEZ:AV0Z50390512 Keywords : cancer susceptibility * molecular epidemiology * genetic susceptibility Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.500, year: 2012

  19. Cefixime disk susceptibility test criteria.

    OpenAIRE

    Fuchs, P C; Barry, A L; Jones, R. N.

    1986-01-01

    A total of 583 bacterial isolates was tested for susceptibility to cefixime by broth microdilution and by disk agar diffusion with 5-, 10-, and 30-microgram disks. At MIC breakpoints of less than or equal to 1.0 and greater than or equal to 4 micrograms/ml for susceptible and resistant, respectively, the 5-microgram disk showed slightly better discrimination. The 5-microgram cefixime disk is recommended with proposed interpretive breakpoint criteria of: less than or equal to 17 mm, resistant;...

  20. Antimicrobial susceptibility of Aeromonas hydrophila.

    OpenAIRE

    Overman, T L

    1980-01-01

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

  1. Comparative metagenomics of disease suppressive soils

    OpenAIRE

    Jack, Allison L.H.; Chapelle, E.; Siegel, Katarzyna; Edel-Hermann, Veronique; Steinberg, Christian; LEMANCEAU Philippe; Raaijmakers, Jos M.

    2013-01-01

    Natural control of soil-borne plant pathogens in disease suppressive soils has been documented for decades in various agricultural systems. Contrary to what is observed in disease conducive soils, suppression is characterized by a low disease incidence in spite of the presence of a susceptible plant host and a virulent pathogen. This phenomenon has been shown in many cases to be biologically-based, however our understanding of the microorganisms, microbial interactions and mechanisms underlyi...

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

    Directory of Open Access Journals (Sweden)

    Rosana Sumiya Gurgel

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

  4. Determination of the dew point and the frost point below 00C making use of the beta-ray backscattering and the electric conductivity on the narrow surface of insulated layer

    International Nuclear Information System (INIS)

    It is necessary to distinguish between the dew point and the frost point below 00C. The freezing of the dew and the melting of the frost are respectively detected by the rapid decrease and the increase of the conduction current on the narrow surface of insulated layer made of epoxy, 0.5 mm in width and 10 mm in length, on which the dew deposits. The dew point -90C and the frost point -80C in the humidity 21% at the temperature 130C are clearly distinguished in this method. (author)

  5. Ice Lens Formation and Frost Heave at the Phoenix Landing Site

    Science.gov (United States)

    Zent, A. P.; Sizemore, H. G.; Remple, 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 excavated by Phoenix. The leading 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 metabolize and grow down to temperatures of at least 258 K.

  6. The MVACS Soil Temperature Probe

    Science.gov (United States)

    Wood, S. E.; Paige, D. A.; Nguyen, A.; Crisp, D.; Alleruzzo, R.; Labaw, C.; Mahoney, C.; Vargas, R.; Gunderson, H.; Braun, D.; Slostad, J.; Manvi, R.; Brown, K.; Oakes, E.

    1999-09-01

    As part of the Mars Volatiles and Climate Surveyor (MVACS) payload on Mars Polar Lander, currently on its way to a Dec. 3, 1999 landing on the south polar layered deposits, the Soil Temperature Probe (STP) will make direct measurements of the temperatures and thermophysical properties of soils and/or ices accessible by the Robotic Arm (RA). The STP consists of a thin, rigid fiberglass tube 15 cm long containing 2 platinum resistance temperature sensors; one in the metal tip which can be heated (PRT-1), and another inside the tube (PRT-2). It is mounted on the side of the scoop at the end of the RA. To make measurements, the RA places the STP in the desired location on or beneath the surface, and Robotic Arm Camera (RAC) image(s) are taken to verify its position, using ruler markings on the STP to measure its depth. The temperatures of both PRT's are recorded every 3 seconds. Data and commanding are handled through the meteorology instruments (MET) electronics package. Measurement of thermophysical properties can be done actively or passively. In active mode, PRT-1 is heated at a constant rate ( 10 mW). The thermal conductivity of the surrounding soil can be derived from the asymptotic temperature rise. The thermal diffusivity (alpha ) can be derived from the transient response. In passive mode alpha can also be determined by measuring the change in the amplitude and phase of the diurnal thermal wave at different depths. The temperature and thermophysical property measurements obtained with the STP will be very useful for interpreting other MVACS observations including air temperature and humidity, the presence or absence of subsurface ice, the identity of any surface frosts (CO_2 or H_2O), and Thermal Evolved Gas Analyzer soil sample analysis. These STP measurements will also provide invaluable "ground truth" for comparison with data from orbiting spacecraft such as Mars Global Surveyor and Mars Climate Orbiter.

  7. Seasonally Frozen Soil Monitoring Using Passive Microwave Satellite Data and Simulation Modeling

    Science.gov (United States)

    Toll, D. L.; Owe, M.; Levine, E.

    1998-01-01

    Satellite data and simulation modeling were used to assess seasonally frozen soils in the central US - Canada borders area (46-53 degrees N and 96-108 degrees). We used Scanning Multichannel Microwave Radiometer (SMMR) satellite data to delineate the top layer of frozen soils. SMMR is a passive microwave sensor having five channels (6.6, 10, 18, 21 and 37 GHz) with a horizontal and vertical polarization. SMRR data are available between 1978-1987 with noon and midnight overpass and footprint sizes between 25 km and 150 km. SMMR data were processed from resampled 1/4 degree grid cells during fall freeze-up and spring thaw (fall 1985 - spring 1987). The dielectric properties of a target may directly affect the satellite signal. The dielectric value is an order of magnitude smaller for frozen soil water. There are other significant changes to the emitted microwave signal from changes to the surface physical temperature, attenuation of the soil signal from plant water and soil moisture. We further characterized the temporal and spatial dynamic of frozen soils using the FroST (Frozen Soil Temperature) simulation model. The FroST model was used to further predict soil water and ice content, and soil temperature. SMMR results were compared versus 5-cm soil temperature data from available weather stations (14 in Canada and 11 for available months in the US). SMMR data were analyzed as a function of frequency, polarization, polarization difference, and "frequency gradient". In addition, vegetation density, physical temperature and snow depth were also considered. Preliminary analysis of SMMR derived frozen soil/thaw classification using a simple threshold classification indicates a mean overall classification accuracy by season of 85 percent. A sensitivity analysis for different soils with varying amounts of snow was conducted with FroST, which showed that the amount of snow, and the time of snow fall and melt affected the ice and water content, and depth of thaw. These results indicate a potential source of flooding and erosion under conditions when melting snow and spring rains provide a source of infiltrating water.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ricardo Pérez-de la Luz

    2011-10-01

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

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

    International Nuclear Information System (INIS)

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

  11. Internal consistency, test-retest reliability and construct validity of the Frost Multidimensional Perfectionism Scale / Consistencia interna, confiabilidad test-retest y validez de constructo de la Escala Multidimensional de Perfeccionismo de Frost

    Scientific Electronic Library Online (English)

    Karina, Franco; Felipe, Díaz; Patricia, Torres; Yolanda, Telléz; Carlos, Hidalgo-Rasmussen.

    2014-12-01

    Full Text Available El propósito de esta investigación fue evaluar la consistencia interna, la confiabilidad test-retest y la validez de constructo de la Frost Multidimensional Perfectionism Scale (FMPS) en mujeres. Se trabajó con una muestra de 325 mujeres universitarias, con una edad promedio de 20.75 años (DE = 2.81 [...] ). Una muestra (n = 189) de participantes contestó la FMPS en dos ocasiones para el test-retest, con una diferencia de un mes o dos meses entre la primera y la segunda aplicación. Los resultados mostraron que el Alpha de Cronbach para el total del instrumento fue de .87 y para los factores el rango fue de .66 a .80. La confiabilidad test-retest a un mes fue de .80 y a dos meses fue de .67. Las personas con sintomatología de trastornos del comportamiento alimentario presentaron puntuaciones significativamente mayores que el grupo control en el total de la escala y tres de sus factores, Preocupación por los Errores, Indecisión de Acción y Expectativas Paternas. Se concluye que existe evidencia favorable sobre la consistencia interna, confiabilidad test retest y validez de constructo de la FMPS. Abstract in english The purpose of this research was to evaluate the internal consistency, the test-retest reliability and the construct validity of the Frost Multidimensional Perfectionism Scale (FMPS) in women. The total sample was made up of 325 university women, with an average age of 20.75 years (SD = 2.81). The s [...] cale was administered twice (n = 189) with an interval of one or two months between the first and second time of administration. Results showed that Cronbach's Alpha for the total score of instrument was .87 and for the factors ranged from .66 to .80. The one-month test-retest reliability was .80 and for the two-months was .67. People with symptomatology of eating disorders showed significantly higher scores than the control group in the total score of the FMPS and three of its factors, Concerns about Mistakes, Doubts about Actions and Parental Expectations. These findings provide favorable evidence for internal consistency, test-retest reliability and construct validity of the FMPS.

  12. DETERMINATIVE ROLE OF PLANT GENOTYPE IN COMPOSITION OF SOIL MICROBIAL COMMUNITIES AND INDUCTION OF SOIL SUPPRESSIVENESS

    Science.gov (United States)

    Suppressive soils are characterized by the absence of disease development even though a virulent pathogen and susceptible host are present. Biotic and abiotic elements of the soil environment contribute to suppressiveness, however most defined systems have identified biological elements as primary ...

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

    Science.gov (United States)

    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. PMID:19068813

  14. Magnetic susceptibility of intermetallic systems

    International Nuclear Information System (INIS)

    The magnetic susceptibility (CHI) is investigated of metallic systems of Cu-Al, Cu-Ga, Cu-In, Cu-Cd, Cu-Zn in a wide temperature range; the character is studied of the dependence of (CHI) upon the temperature and the concentration. The results tend to indicate that where the systems feature an ''electron'' type of chemical interaction, the compositions of the ?-phase in solid state correlate with the extremal values of the magnetic susceptibility. The character of the dependence of the magnetic susceptibility of analog compounds upon the parameter of the crystalline lattice is adequately described by the Jones theory. Melting of the compounds alters completely the character of the interaction between the components, this being indicated by the disappearance on the isotherms ''CHI vs. composition'' of a minimum of the property characteristic of solid state and by a decrease in CHI of melts with the increase of the total sum of the order numbers of components

  15. Inherited susceptibility and radiation exposure

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    O.A. Borovik

    2013-11-01

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

  17. Antimicrobial resistance among Pseudomonas spp. and the Bacillus cereus group isolated from Danish agricultural soil

    DEFF Research Database (Denmark)

    Jensen, Lars Bogø; Baloda, S.; Boye, Mette; Aarestrup, Frank Møller

    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-n...

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

    Indian Academy of Sciences (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.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Schjønning, Per; Møldrup, Per; Razzaghi, Fatemah; Tuller, Marcus; de Jonge, Lis Wollesen

    2014-01-01

    microbial community (65–100% increase in FDA). Incubation led to significant macroaggregate formation (>2 mm) for all soils. Friability and strength of newly-formed aggregates were negatively correlated with clay content and carbon content, respectively. Soil workability was best for the kaolinite-rich soil...... and poorest for the smectite-rich soil; for illitic soils, workability increased with increasing organic carbon content. Organic amendment decreased the compression susceptibility of intact, incubated samples at smaller stress values (<200 kPa)....

  2. Susceptibility of Aeromonas Hydophila Isolates to Antimicrobial Drugs

    Directory of Open Access Journals (Sweden)

    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 flumequine and 40% to Oxitetracycline.

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

    Science.gov (United States)

    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.

  4. Soils - NRCS Web Soil Survey

    Data.gov (United States)

    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...

  5. Magnetic Susceptibility Modelling Using ANSYS.

    Czech Academy of Sciences Publication Activity Database

    Bartušek, Karel; ?áp, M.; Marcon, P.; Mikulka, J.

    Cambridge : The Electromagnetics Academy, 2011, s. 190-193. ISBN 978-1-934142-16-5. [PIERS 2011 Marrakesh. Marrakesh (MA), 20.04.2011-23.04.2011] R&D Projects: GA ?R GA102/09/0314 Institutional research plan: CEZ:AV0Z20650511 Keywords : magnetic susceptibility * NMR * ANSYS * APDL Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. The Ising Susceptibility Scaling Function

    CERN Document Server

    Chan, Y; Nickel, B G; Perk, J H H

    2011-01-01

    We have dramatically extended the zero field susceptibility series at both high and low temperature of the Ising model on the square, triangular and honeycomb lattices, and used these data to calculate a number of terms in the scaling function expansion around both the ferromagnetic and, for the square and honeycomb lattices, the antiferromagnetic critical point.

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

    Science.gov (United States)

    Tejnil, Edward; Rogers, Stuart E.

    2012-01-01

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

  8. Polarization Observables for Double-Pion Photoproduction using a Linearly Polarized Photon Beam and a Transversely Polarized Target from FROST

    Science.gov (United States)

    Roy, P.; Crede, V.

    2014-03-01

    One of the prominent ways to understand quark-gluon interactions in baryons in the low-energy regime is studying the baryon spectrum. The present world database of baryon resonances is inadequate to interpret the spectrum in terms of the relevant degrees of freedom. Double-pion photoproduction, which dominates the total photoabsorption cross section above 1.7 GeV, serves as an important reaction to get access to the higher mass resonances. Cross sections and polarization observables for the double-pion reaction will provide information about the scattering amplitudes and assist in isolating the resonant contributions to the reaction. Here we report on the analysis technique and preliminary results on polarization observables obtained from the study of ?+?- photoproduction using a transversely polarized FROzen Spin butanol Target (FROST) and a linearly polarized photon beam. The experiment was conducted at Jefferson Lab using the CLAS spectrometer. The coherent edge of the linearly polarized beam ranged from 0.9 to 2.1 GeV and we were able to bin the data in 3 kinematic variables. A salient feature of this analysis was the use of an event-based quality factor technique to separate signal from background that originated from bound nucleons present in the target. This work is supported by DOE # DE-FG02-92ER40735.

  9. The frost gene of Neurospora crassa is a homolog of yeast cdc1 and affects hyphal branching via manganese homeostasis.

    Science.gov (United States)

    Sone, T; Griffiths, A J

    1999-12-01

    The Neurospora crassa mutant frost has a hyperbranching phenotype that can be corrected by adding Ca(2+), suggesting that characterization of this gene might clarify the mechanism of Ca(2+)-dependent tip growth. The wild-type allele was cloned by sib selection using protoplasts from arthroconidia. RFLP analysis revealed that the cloned DNA fragment mapped to the fr locus. The nucleotide sequence of genomic and cDNA was determined. The deduced amino acid sequence showed homology to the Saccharomyces cerevisiae CDC1 protein, implicated in manganese homeostasis. The fr mutant was sensitive to Mn(2+), and a revertant allele whose product differs by one amino acid was tolerant to Mn(2+). Mn(2+) depletion induced the wild-type strain to hyperbranch, resulting in a morphology similar to that of fr. The fr mutant was also sensitive to calcineurin inhibitors. These results suggest that fr is involved in Mn(2+) homeostasis and point to a role for Mn(2+) in Neurospora branching. PMID:10669587

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

    Data.gov (United States)

    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.

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

    Data.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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. Identifying areas susceptible to desertification in the Brazilian northeast

    Science.gov (United States)

    Vieira, R. M. S. P.; Tomasella, J.; Alvalá, R. C. S.; Sestini, M. F.; Affonso, A. G.; Rodriguez, D. A.; Barbosa, A. A.; Cunha, A. P. M. A.; Valles, G. F.; Crepani, E.; de Oliveira, S. B. P.; de Souza, M. S. B.; Calil, P. M.; de Carvalho, M. A.; Valeriano, D. M.; Campello, F. C. B.; Santana, M. O.

    2015-03-01

    Approximately 57% of the Brazilian northeast region is recognized as semi-arid 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 11 influencing 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, conservation units) which were 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 results indicate 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% (83.4 km2) from 2000 to 2010. The implementation of the methodology provides the technical basis for decision-making that involves mitigating actions and the first comprehensive national assessment within the United Nations Convention to Combat Desertification framework.

  14. Identifying areas susceptible to desertification in the Brazilian Northeast

    Directory of Open Access Journals (Sweden)

    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.

  15. Effects of CT Number-Derived Matrix Density on Preferential Flow 1 and Transport in a Macroporous Agricultural Soil

    DEFF Research Database (Denmark)

    Katuwal, Sheela; Moldrup, Per; Lamandé, Mathieu; Tuller, Markus; de Jonge, Lis Wollesen

    2015-01-01

    Preferential flow and transport in structured soils can be intimately linked to numerous environmental problems. Surface-applied chemicals are susceptible to rapid transport in structural soil pores to deeper depths, thereby potentially contaminating valuable environmental resources and posing ri...

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

    KAUST Repository

    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.

  17. Soil stabilization

    Directory of Open Access Journals (Sweden)

    K. Subba Rao

    1952-09-01

    Full Text Available The subject of soil stabilization has been reviewed. The various stabilizing agents and the different methods of soil stabilization have been considered. Soil stability is dependent on the two important properties of soils-cohesion and internal-friction. A proper adjustment of these two properties and also water proofing are the main lines of approach to the problem of soil stabilization

  18. The influence of time on the magnetic properties of late Quaternary periglacial and alluvial surface and buried soils along the Delaware River, USA

    OpenAIRE

    GaryEStinchcomb; DanielJPeppe

    2014-01-01

    Magnetic susceptibility of soils has been used as a proxy for rainfall, but other factors can contribute to magnetic enhancement in soils. Here we explore influence of century- to millennial-scale duration of soil formation on periglacial and alluvial soil magnetic properties by assessing three terraces with surface and buried soils ranging in exposure ages from

  19. The influence of time on the magnetic properties of late Quaternary periglacial and alluvial surface and buried soils along the Delaware River, USA

    OpenAIRE

    Stinchcomb, Gary E.; Peppe, Daniel J.

    2014-01-01

    Magnetic susceptibility of soils is a common proxy for rainfall, but other factors can contribute to magnetic enhancement in soils. Here we explore influence of century- to millennial-scale duration of soil formation on periglacial and alluvial soil magnetic properties by assessing three terraces with surface and buried soils ranging in exposure ages from

  20. Genetic susceptibility to childhood leukaemia

    International Nuclear Information System (INIS)

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

  1. Genetic Susceptibility to Rhodococcus equi.

    Science.gov (United States)

    McQueen, C M; Dindot, S V; Foster, M J; Cohen, N D

    2015-11-01

    Rhodococcus equi pneumonia is a major cause of morbidity and mortality in neonatal foals. Much effort has been made to identify preventative measures and new treatments for R. equi with limited success. With a growing focus in the medical community on understanding the genetic basis of disease susceptibility, investigators have begun to evaluate the interaction of the genetics of the foal with R. equi. This review describes past efforts to understand the genetic basis underlying R. equi susceptibility and tolerance. It also highlights the genetic technology available to study horses and describes the use of this technology in investigating R. equi. This review provides readers with a foundational understanding of candidate gene approaches, single nucleotide polymorphism-based, and copy number variant-based genome-wide association studies, and next generation sequencing (both DNA and RNA). PMID:26340305

  2. Genetic susceptibility to environmental toxicants

    DEFF Research Database (Denmark)

    2001-01-01

    The toxicological challenges to the chemical industry have in recent years been greatly affected by the rapid innovation and development of analytical, molecular and genetic technologies. ECETOC recognises the importance of developing the technical and intellectual skill bases in academia and...... industrial based laboratories to meet the rapid development of the science base of toxicology. As the technology to determine genetic susceptibility develops, so scientist will be able to describe altered gene expression provoked by chemicals long before they are able to offer valid interpretations of their...... technology combined with well conducted clinical trials and epidemiological studies will greatly improve our chances of devising strategies for the reduction of harm. This symposium can, at least in part, make a contribution to our current understanding of genetic susceptibility to environmental toxicants...

  3. Topological susceptibility from the overlap

    CERN Document Server

    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 ...

  4. Uniform susceptibilities of metallic elements

    International Nuclear Information System (INIS)

    The exchange-correlation enhanced spin susceptibilities of 32 metallic elements from Li through In have been calculated using the spin-polarized exchange-correlation functional of von Barth and Hedin. Since these 32 elements include both the 3d and 4d transition series, the calculations clearly exhibit both the normal trends with atomic number and the anomalies responsible for ferromagnetism. The susceptibilities were obtained by evaluating the Vosko-Perdew approximate formal solution of the linear-response problem for each element, using fully self-consistent nonmagnetic ground-state energy bands and wave functions. In addition, the accuracy of the Vosko-Perdew approximation itself was tested for Cr by performing a separate nonperturbative spin-polarized calculation of the response (for the same exchange-correlation functional) to an external magnetic field for this metal

  5. Antimycotics susceptibility testing of dermatophytes

    Directory of Open Access Journals (Sweden)

    Arsi?-Arsenijevi? 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.

  6. Genetic susceptibility to lead poisoning.

    OpenAIRE

    Onalaja, A O; Claudio, L

    2000-01-01

    Major strides have been taken in the regulation of lead intoxication in the general population, but studies using genetic markers of susceptibility to environmental toxicants raise the question of whether genes can make certain individuals more vulnerable to environmental toxins such as lead. At least three polymorphic genes have been identified that potentially can influence the bioaccumulation and toxicokinetics of lead in humans. The first gene to be discussed in this review is the gene co...

  7. Antimicrobial susceptibility of Haemophilus ducreyi.

    OpenAIRE

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

    1990-01-01

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

  8. Tuberculosis Susceptibility of Diabetic Mice

    OpenAIRE

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

    2007-01-01

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

  9. Antibiotic susceptibility of Atopobium vaginae

    Directory of Open Access Journals (Sweden)

    Verschraegen Gerda

    2006-03-01

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

  10. Landslide susceptibility mapping using a neuro-fuzzy

    Science.gov (United States)

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

    2009-12-01

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

  11. Decreased hybrid susceptibility to murine myeloma grafts

    International Nuclear Information System (INIS)

    The behavior of BALB/c myeloma transplants in (C57BL/10 x BALB/c)F1 hybrids was investigated. The F1 hybrids were less susceptible to the grafts than were the parental BALB/c hosts. Host susceptibility was x-ray and cyclophosphamide sensitive, but an immune hypothesis was not favored since no memory was demonstrable. Males were less susceptible than females, and rabbit antithymus serum had no effect on susceptibility

  12. Soil erodibility degree assessment on hilly terrain

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    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 2 meters.

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

    OpenAIRE

    Arvidsson, J; Sjöberg, E.; Akker, J.J.H., van de

    2003-01-01

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

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

    Science.gov (United States)

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

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

  16. Influence of acidic fog on the frost sensitivity of young spruces (Picea abies (L.) Karst.); Einfluss von saurem Nebel auf die Frostempfindlichkeit von jungen Fichten (Picea abies (L.) Karst.)

    Energy Technology Data Exchange (ETDEWEB)

    Esch, A.

    1994-12-31

    The investigations had the purpose to establish the effect of acidic fog during frost periods in winter and spring. Four to five year old spruces in vessels were first treated with acidic fog in autumn, then exposed to frost in winter, either in the form of a frost shock, or subsequently to a hardening treatment. In an additional experiment, plants were exposed to frost dryness in spring, equally with previous exposure to acidic fog. The study looked into possible symptoms of damage in the needles and the trees` water, carbon and mineral budgets. Accompanying gas exchange measurements were carried out in order to document the transpiration behaviour and photosynthesis performance of the trees before and after the frost experiments. (orig.) [Deutsch] Die vorliegenden Untersuchungen hatten zum Ziel, die Wirkung einer Saeurebelastung im Nebel waehrend Frostperioden im Winter sowie im Fruehjahr aufzuzeigen. Hierbei waren vier- bzw. fuenfjaehrige Fichten in Gefaessversuchen nach vorangegangener Schadstoffnebelbehandlung im Herbst waehrend des Winters einer Frostbelastung als Frostschock bzw. nach einer vorangegangenen Abhaertung ausgesetzt. Zusaetzlich wurde eine Kaeltebelastung als Frosttrocknis im Fruehjahr ebenfalls nach vorhergehender Belastung mit saurem Nebel simuliert. Gegenstand der Untersuchungen waren moegliche Schadsymptome an den Nadeln sowie der Wasser-, der Kohlenstoff- als auch der Mineralstoffhaushalt der Baeume. Begleitend wurden Gaswechselmessungen vorgenommen, die das Transpirationsverhalten als auch die Photosyntheseleistung der Baeume vor und nach den jeweiligen Frostbelastungssituationen beschreiben sollten. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Martín Ariel Hadad

    2012-01-01

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

  18. An experimental study on the negative effects of downwards flow of the melted frost over a multi-circuit outdoor coil in an air source heat pump during reverse cycle defrosting

    International Nuclear Information System (INIS)

    Highlights: • A special experimental rig was built and its details are reported. • The negative effects of downwards flowing of the melted frost were shown. • Defrosting duration was shortened after installing water collecting trays. • Temperature of melted frost decreased after installing trays. - Abstract: When the surface temperature of the outdoor coil in an air source heat pump (ASHP) unit is lower than both freezing point of water and the air dew point, frost can be formed and accumulated over outdoor coil surface. Frosting affects the energy efficiency, and periodic defrosting therefore is necessary. Reverse cycle defrosting is currently the most widely used defrosting method. A previous related study has indicated that during reverse cycle defrosting, downwards flow of the melted frost over a multi-circuit outdoor coil could affect the defrosting performance, without however giving detailed quantitative analysis of the effects. Therefore an experimental study on the effects has been carried out and a quantitative analysis conducted using the experimental data. In this paper, the detailed description of an experimental ASHP unit which was specifically built up is firstly reported. This is followed by presenting experimental results. Result analysis and conclusions are finally given

  19. Soil proteomics

    DEFF Research Database (Denmark)

    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-...

  20. Soil friability

    DEFF Research Database (Denmark)

    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 ...

  1. Soil Compactability

    OpenAIRE

    Seig, D. A.

    1985-01-01

    Subsoiling and deep loosening are widely used to alleviate soil compaction but little is known about the mechanics of the compaction process. Further information is required on the process that soil goes through during compaction, along with the effect on the amount of soil compaction of various tyre configurations. Such information will allow more confident recommendations to farmers on the suceptability of their soil to compaction. Experimental work was conducted whe...

  2. Specific features of the dynamics of epiphytic and soil yeast communities in the thickets of Indian balsam on mucky gley soil

    Science.gov (United States)

    Glushakova, A. M.; Kachalkin, A. V.; Chernov, I. Yu.

    2011-08-01

    The annual dynamics of the number and taxonomic composition of yeast communities were studied in the phyllosphere, on the flowers, and on the roots of Indian balsam ( Impatiens glandulifera Royle) and in the mucky gley soil under the thickets of this plant. It was shown that typical phyllosphere yeast communities with a predominance of the red-pigmented species Rhodotorula mucilaginosa and Rhodotorula glutinis and the typical epiphyte Cryptococcus magnus are formed on the leaves of this annual hygrophyte. However, yeast groups with a predominance of the ascosporous species Saccharomyces paradoxus, Kazachstania barnettii, and Torulaspora delbrueckii, which are not typical of soils at all, were found in the mucky gley soil under the thickets of Indian balsam. Thus, the epiphytic and soil yeast complexes under the thickets of Indian balsam are represented by two entirely discrete communities without common species. In other biogeocenoses of the forest zone, the rearrangement of the structure of yeast communities in passing from the aboveground substrates to the soil proceeds gradually, and most of the species can be isolated both from the aboveground parts of plants and from the soil. The strong difference between the yeast communities in the phyllosphere of Indian balsam and in the soil under its thickets is apparently related to the fact that the annual hygrophytes are decomposed very quickly (during several days after the first frosts). Because of this, an intermediate layer between the phyllosphere and the soil (the litter layer), in which epiphytic microorganisms can develop, is not formed under these plants.

  3. Biofilms and Antifungal Susceptibility Testing.

    Science.gov (United States)

    Simitsopoulou, Maria; Chatzimoschou, Athanasios; Roilides, Emmanuel

    2016-01-01

    Yeasts and filamentous fungi both exist as single cells and hyphal forms, two morphologies used by most fungal organisms to create a complex multilayered biofilm structure. In this chapter we describe the most widely used assays for the determination of biofilm production and assessment of susceptibility of biofilms to antifungal agents or host phagocytes as various methods, the most frequent of which are staining, confocal laser scanning microscopy, quantification of extracellular DNA and protein associated with extracellular matrix and XTT metabolic reduction assay. Pathway-focused biofilm gene expression profiling is assessed by real-time reverse transcriptase polymerase chain reaction. PMID:26519074

  4. TGFBR1 and Cancer Susceptibility

    OpenAIRE

    PASCHE, BORIS; Michael J. Pennison; Jimenez, Hugo; Wang, Minghui

    2014-01-01

    Transforming growth factor beta (TGF-?) is a potent inhibitor of cell growth. TGFBR1*6A is a polymorphism consisting of a 9-base pair in-frame deletion within exon 1 of the type I TGF-? receptor (TGFBR1), which results in a receptor with decreased TGF-? signaling capability. The discovery of an association between TGFBR1*6A and cancer susceptibility led to the hypothesis that hypomorphic variants of the TGF-? signaling pathway may predispose to the development of cancer. This hypothesis was t...

  5. Viscoelastic ferrogel: dynamic magnetic susceptibilities

    Scientific Electronic Library Online (English)

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

    2001-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

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

    Directory of Open Access Journals (Sweden)

    Velci Queiróz de Souza

    2011-06-01

    Full Text Available O presente trabalho teve como objetivo avaliar a resposta das espécies arbóreas Schizolobium parahyba (Vell. Blake (guapuruvu, Mimosa scabrella Benth. (bracatinga, Peltophorum dubium (Spr. Taubert (canafístula, Parapiptadenia rigida (Benth. Brenan (angico-vermelho e o híbrido Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto em consórcio com a cana-de-açúcar (Saccharum spp. em dois arranjos de sistemas agroflorestais (faixa - 3x3m + 12m e linha - 6x1,5m submetidos a extremos climáticos de geada, na região Noroeste do Rio Grande do Sul. Os danos (resistência á geada foram avaliados segundo o sistema de notas utilizado por HIGA et al. (2000 no qual atribuiu-se uma