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Sample records for runoff temperature electronic

  1. Does runoff or temperature control chemical weathering rates?

    International Nuclear Information System (INIS)

    Eiriksdottir, Eydis Salome; Gislason, Sigurdur Reynir; Oelkers, Eric H.

    2011-01-01

    Highlights: → The rate chemical weathering is affected by both temperature and runoff. Separating out these two factors is challenging because runoff tends to increase with increasing temperature. → In this study, natural river water samples collected on basaltic catchments over a five year period are used together with experimentally derived dissolution rate model for basaltic glass to pull apart the effects of runoff and temperature. → This study shows that the rate of chemical denudation is controlled by both temperature and runoff, but is dominated by runoff. - Abstract: The rate of chemical denudation is controlled by both temperature and runoff. The relative role of these two factors in the rivers of NE Iceland is determined through the rigorous analysis of their water chemistry over a 5-a period. River catchments are taken to be analogous to laboratory flow reactors; like the fluid in flow reactors, the loss of each dissolved element in river water is the sum of that of the original rainwater plus that added from kinetically controlled dissolution and precipitation reactions. Consideration of the laboratory determined dissolution rate behaviour of basalts and measured water chemistry indicates that the maximum effect of changing temperature on chemical denudation in the NE Icelandic rivers was 5-25% of the total change, whereas that of runoff was 75-95%. The bulk of the increased denudation rates with runoff appear to stem from an increase in reactive surface area for chemical weathering of catchment solids.

  2. Impervious surfaces and sewer pipe effects on stormwater runoff temperature

    Science.gov (United States)

    Sabouri, F.; Gharabaghi, B.; Mahboubi, A. A.; McBean, E. A.

    2013-10-01

    The warming effect of the impervious surfaces in urban catchment areas and the cooling effect of underground storm sewer pipes on stormwater runoff temperature are assessed. Four urban residential catchment areas in the Cities of Guelph and Kitchener, Ontario, Canada were evaluated using a combination of runoff monitoring and modelling. The stormwater level and water temperature were monitored at 10 min interval at the inlet of the stormwater management ponds for three summers 2009, 2010 and 2011. The warming effect of the ponds is also studied, however discussed in detail in a separate paper. An artificial neural network (ANN) model for stormwater temperature was trained and validated using monitoring data. Stormwater runoff temperature was most sensitive to event mean temperature of the rainfall (EMTR) with a normalized sensitivity coefficient (Sn) of 1.257. Subsequent levels of sensitivity corresponded to the longest sewer pipe length (LPL), maximum rainfall intensity (MI), percent impervious cover (IMP), rainfall depth (R), initial asphalt temperature (AspT), pipe network density (PND), and rainfall duration (D), respectively. Percent impervious cover of the catchment area (IMP) was the key parameter that represented the warming effect of the paved surfaces; sensitivity analysis showed IMP increase from 20% to 50% resulted in runoff temperature increase by 3 °C. The longest storm sewer pipe length (LPL) and the storm sewer pipe network density (PND) are the two key parameters that control the cooling effect of the underground sewer system; sensitivity analysis showed LPL increase from 345 to 966 m, resulted in runoff temperature drop by 2.5 °C.

  3. Independent effects of temperature and precipitation on modeled runoff in the conterminous United States

    Science.gov (United States)

    McCabe, G.J.; Wolock, D.M.

    2011-01-01

    A water-balance model is used to simulate time series of water-year runoff for 4 km ?? 4 km grid cells for the conterminous United States during the 1900-2008 period. Model outputs are used to examine the separate effects of precipitation and temperature on runoff variability. Overall, water-year runoff has increased in the conterminous United States and precipitation has accounted for almost all of the variability in water-year runoff during the past century. In contrast, temperature effects on runoff have been small for most locations in the United States even during periods when temperatures for most of the United States increased significantly. Copyright 2011 by the American Geophysical Union.

  4. Abrupt Greenland Ice Sheet runoff and sea water temperature changes since 1821, recorded by coralline algae

    Science.gov (United States)

    Kamenos, N.; Hoey, T.; Bedford, J.; Claverie, T.; Fallick, A. E.; Lamb, C. M.; Nienow, P. W.; O'Neill, S.; Shepherd, I.; Thormar, J.

    2012-12-01

    The Greenland Ice Sheet (GrIS) contains the largest store of fresh water in the northern hemisphere, equivalent to ~7.4m of eustatic sea level rise, but its impacts on current, past and future sea level, ocean circulation and European climate are poorly understood. Previous estimates of GrIS melt, from 26 years of satellite observations and temperature driven melt-models over 48 years, show a trend of increasing melt. There are however no runoff data of comparable duration with which to validate temperature-based runoff models, or relationships between the spatial extent of melt and runoff. Further, longer runoff records that extend GrIS melt records to centennial timescales will enable recently observed trends to be put into a better historical context. We measured Mg/Ca, δ18O and structural cell size in annual growth bands of red coralline algae to reconstruct: (1) near surface sea water temperature; and, (2) melt/runoff from the GrIS. (1) Temperature: we reconstructed the longest (1821-2009) sub-annual resolution record of water temperature in Disko Bugt (western Greenland) showing an abrupt change in temperature oscillation patterns during the 1920s which may be attributable to the interaction between atmospheric temperature and mass loss from Jakobshavn Isbrae glacier. (2) GrIS runoff: using samples from distal parts of Søndre Strømfjord we produced the first reconstruction of decadal (1939-2002) GrIS runoff. We observed significant negative relationships between historic runoff, relative salinity and marine summer temperature. Our reconstruction shows a trend of increasing reconstructed runoff since the mid 1980s. In situ summer marine temperatures followed a similar trend. We suggest that since 1939 atmospheric temperatures have been important in forcing runoff. Subject to locating in situ coralline algae samples, these methods can be applied across hundreds to thousands of years. These results show that our technique has significant potential to enhance

  5. Sensitivities of dry season runoff to precipitation and temperature in southern Sierra Nevada streams

    Science.gov (United States)

    Safeeq, M.; Hunsaker, C. T.; Bales, R. C.

    2016-12-01

    In a mediterranean climate, dry season runoff sustains water supply and supports aquatic habitat and other ecosystems. Precipitation and temperature directly, by regulating recharge and evapotranspiration (ET), and indirectly, by regulating amount and timing of snowmelt, control the dry season runoff in the Sierra Nevada. Here, we explored relative impacts of precipitation and temperature variability on dry season runoff using path analysis. Specific objectives include: (i) to quantify the direct and indirect impacts of precipitation and temperature on 7-day average minimum flow (Qmin) and (ii) to explore the role of preceding year Qmin on fall season runoff (QF). We used daily runoff, air temperature, precipitation, and snow water equivalent (SWE) over 2004-2015 for the ten catchments in the Kings River Experimental Watersheds. For path analysis model of Qmin, we defined annual precipitation and temperature as exogenous variables and peak SWE, day of snow disappearance, and Qmin as endogenous variables. For QF, we defined current year fall precipitation and preceding year Qmin as exogenous variables and current year QF as an endogenous variable. Path analysis results for Qmin show precipitation as a dominant driver when compared to temperature, peak SWE, and day of snow disappearance. However, in half of the catchments that are mostly located at higher elevations the impact of temperature on Qmin was either comparable or exceeded that of precipitation. This relatively high sensitivity of Qmin to air temperature in high elevation catchments is consistent with the earlier findings of increased ET in proportion to warming. The direct effects of peak SWE and day of snow disappearance on Qmin were limited, and indirect effects of temperature and precipitation via peak SWE and day of snow disappearance were not significant. The preceding year Qmin and fall precipitation showed comparable impacts on QF, indicating that the storage in the preceding year modulates current

  6. Future shift of the relative roles of precipitation and temperature in controlling annual runoff in the conterminous United States

    Directory of Open Access Journals (Sweden)

    K. Duan

    2017-11-01

    Full Text Available This study examines the relative roles of climatic variables in altering annual runoff in the conterminous United States (CONUS in the 21st century, using a monthly ecohydrological model (the Water Supply Stress Index model, WaSSI driven with historical records and future scenarios constructed from 20 Coupled Model Intercomparison Project Phase 5 (CMIP5 climate models. The results suggest that precipitation has been the primary control of runoff variation during the latest decades, but the role of temperature will outweigh that of precipitation in most regions if future climate change follows the projections of climate models instead of the historical tendencies. Besides these two key factors, increasing air humidity is projected to partially offset the additional evaporative demand caused by warming and consequently enhance runoff. Overall, the projections from 20 climate models suggest a high degree of consistency on the increasing trends in temperature, precipitation, and humidity, which will be the major climatic driving factors accounting for 43–50, 20–24, and 16–23 % of the runoff change, respectively. Spatially, while temperature rise is recognized as the largest contributor that suppresses runoff in most areas, precipitation is expected to be the dominant factor driving runoff to increase across the Pacific coast and the southwest. The combined effects of increasing humidity and precipitation may also surpass the detrimental effects of warming and result in a hydrologically wetter future in the east. However, severe runoff depletion is more likely to occur in the central CONUS as temperature effect prevails.

  7. Future shift of the relative roles of precipitation and temperature in controlling annual runoff in the conterminous United States

    Science.gov (United States)

    Duan, Kai; Sun, Ge; McNulty, Steven G.; Caldwell, Peter V.; Cohen, Erika C.; Sun, Shanlei; Aldridge, Heather D.; Zhou, Decheng; Zhang, Liangxia; Zhang, Yang

    2017-11-01

    This study examines the relative roles of climatic variables in altering annual runoff in the conterminous United States (CONUS) in the 21st century, using a monthly ecohydrological model (the Water Supply Stress Index model, WaSSI) driven with historical records and future scenarios constructed from 20 Coupled Model Intercomparison Project Phase 5 (CMIP5) climate models. The results suggest that precipitation has been the primary control of runoff variation during the latest decades, but the role of temperature will outweigh that of precipitation in most regions if future climate change follows the projections of climate models instead of the historical tendencies. Besides these two key factors, increasing air humidity is projected to partially offset the additional evaporative demand caused by warming and consequently enhance runoff. Overall, the projections from 20 climate models suggest a high degree of consistency on the increasing trends in temperature, precipitation, and humidity, which will be the major climatic driving factors accounting for 43-50, 20-24, and 16-23 % of the runoff change, respectively. Spatially, while temperature rise is recognized as the largest contributor that suppresses runoff in most areas, precipitation is expected to be the dominant factor driving runoff to increase across the Pacific coast and the southwest. The combined effects of increasing humidity and precipitation may also surpass the detrimental effects of warming and result in a hydrologically wetter future in the east. However, severe runoff depletion is more likely to occur in the central CONUS as temperature effect prevails.

  8. Investigating runoff efficiency in upper Colorado River streamflow over past centuries

    Science.gov (United States)

    Woodhouse, Connie A.; Pederson, Gregory T.

    2018-01-01

    With increasing concerns about the impact of warming temperatures on water resources, more attention is being paid to the relationship between runoff and precipitation, or runoff efficiency. Temperature is a key influence on Colorado River runoff efficiency, and warming temperatures are projected to reduce runoff efficiency. Here, we investigate the nature of runoff efficiency in the upper Colorado River (UCRB) basin over the past 400 years, with a specific focus on major droughts and pluvials, and to contextualize the instrumental period. We first verify the feasibility of reconstructing runoff efficiency from tree-ring data. The reconstruction is then used to evaluate variability in runoff efficiency over periods of high and low flow, and its correspondence to a reconstruction of late runoff season UCRB temperature variability. Results indicate that runoff efficiency has played a consistent role in modulating the relationship between precipitation and streamflow over past centuries, and that temperature has likely been the key control. While negative runoff efficiency is most common during dry periods, and positive runoff efficiency during wet years, there are some instances of positive runoff efficiency moderating the impact of precipitation deficits on streamflow. Compared to past centuries, the 20th century has experienced twice as many high flow years with negative runoff efficiency, likely due to warm temperatures. These results suggest warming temperatures will continue to reduce runoff efficiency in wet or dry years, and that future flows will be less than anticipated from precipitation due to warming temperatures.

  9. Observed magnified runoff response to rainfall intensification under global warming

    International Nuclear Information System (INIS)

    Huang, Jr-Chuan; Lee, Tsung-Yu; Lee, Jun-Yi

    2014-01-01

    Runoff response to rainfall intensification under global warming is crucial, but is poorly discussed due to the limited data length and human alteration. Historical rainfall and runoff records in pristine catchments in Taiwan were investigated through trend analysis and cross temperature difference analysis. Trend analysis showed that both rainfall and runoff in the 99.9-percentile have been significantly increasing in terms of frequency and intensity over the past four decades. Cross temperature difference analysis quantified that the rainfall and runoff extremes (including the 99.0–99.9-percentiles) may increase by 69.5% and 99.8%, respectively, under a future scenario of 1  ° C increase in temperature. This increase in intensity resembles the increase in intensity observed between 1971–1990 and 1991–2010. The amplified runoff response can be related to the limited catchment storage capacity being preoccupied by rainfall extremes. The quantified temperature effect on rainfall and runoff intensification can be a strong basis for designing scenarios, confirming and fusing GCMs’ results. In addition, the runoff amplification should be a warning for other regions with significant rainfall intensification. Appropriate strategies are indispensable and urgently needed to maintain and protect the development of societies. (paper)

  10. Century-scale variability in global annual runoff examined using a water balance model

    Science.gov (United States)

    McCabe, G.J.; Wolock, D.M.

    2011-01-01

    A monthly water balance model (WB model) is used with CRUTS2.1 monthly temperature and precipitation data to generate time series of monthly runoff for all land areas of the globe for the period 1905 through 2002. Even though annual precipitation accounts for most of the temporal and spatial variability in annual runoff, increases in temperature have had an increasingly negative effect on annual runoff after 1980. Although the effects of increasing temperature on runoff became more apparent after 1980, the relative magnitude of these effects are small compared to the effects of precipitation on global runoff. ?? 2010 Royal Meteorological Society.

  11. Documentation of a daily mean stream temperature module—An enhancement to the Precipitation-Runoff Modeling System

    Science.gov (United States)

    Sanders, Michael J.; Markstrom, Steven L.; Regan, R. Steven; Atkinson, R. Dwight

    2017-09-15

    A module for simulation of daily mean water temperature in a network of stream segments has been developed as an enhancement to the U.S. Geological Survey Precipitation Runoff Modeling System (PRMS). This new module is based on the U.S. Fish and Wildlife Service Stream Network Temperature model, a mechanistic, one-dimensional heat transport model. The new module is integrated in PRMS. Stream-water temperature simulation is activated by selection of the appropriate input flags in the PRMS Control File and by providing the necessary additional inputs in standard PRMS input files.This report includes a comprehensive discussion of the methods relevant to the stream temperature calculations and detailed instructions for model input preparation.

  12. Long-term runoff changes in regions of Slovakia

    International Nuclear Information System (INIS)

    Miklanek, Pavol; Pekarova; Pavla

    2004-01-01

    Mean annual runoff variability includes both natural and anthropogenic (climate change) impacts. Aim of the paper is to identify the long-term trends and the cyclic runoff components of selected Slovak rivers for the period 1931-2000, and of the Danube river for the period 1840-2000. The variability is analysed by the long-term runoff trends of 27 Slovak rivers for the period 1931-2000. The stations were included into the Slovak National Climate Program and they are supposed not to be influenced by anthropogenic activities except of possible climate change. Comparison of the monthly runoff series of the 27 rivers allowed us to draw 3 regions with different runoff trends on the territory of Slovakia (constant trend in Northern and Eastern Slovakia, slow decrease in Central Slovakia, and rapid decrease in Southern Slovakia; The identification of different cyclic components of the runoff series is included. The length of the series allows to identify the 22-year cycles as maximum. By means of the longer runoff series of the Danube river it is shown that the more dry periods occurred in the central Europe and Slovakia in mid 19 th century. The longer Danube series were used also to find the longer runoff cycles of about 31 and 46 years. The mean annual temperature in Europe was lower by 0.6 o C in mid 19 th century compared to 1990s. The temperature increase is put down to climate change impact. The driest period shown by Danube runoff series in mid 19 th century occurred before the start of the climate change. Therefore it is probable that the long-term runoff variability has its own dynamics as well. (Author)

  13. Synchronism of runoff response to climate change in Kaidu River Basin in Xinjiang, Northwest China

    Institute of Scientific and Technical Information of China (English)

    Jie Xue; JiaQiang Lei; DongWei Gui; JianPing Zhao; DongLei Mao; Jie Zhou

    2016-01-01

    The runoff in alpine river basins where the runoff is formed in nearby mountainous areas is mainly affected by temperature and precipitation. Based on observed annual mean temperature, annual precipitation, and runoff time-series datasets during 1958–2012 within the Kaidu River Basin, the synchronism of runoff response to climate change was analyzed and iden-tified by applying several classic methods, including standardization methods, Kendall's W test, the sequential version of the Mann-Kendall test, wavelet power spectrum analysis, and the rescaled range (R/S) approach. The concordance of the nonlinear trend variations of the annual mean temperature, annual precipitation, and runoff was tested significantly at the 0.05 level by Kendall's W method. The sequential version of the Mann-Kendall test revealed that abrupt changes in annual runoff were synchronous with those of annual mean temperature. The periodic characteristics of annual runoff were mainly consistent with annual precipitation, having synchronous 3-year significant periods and the same 6-year, 10-year, and 38-year quasi-periodicities. While the periodic characteristics of annual runoff in the Kaidu River Basin tracked well with those of annual precipitation, the abrupt changes in annual runoff were synchronous with the annual mean temperature, which directly drives glacier- and snow-melt processes. R/S analysis indicated that the annual mean temperature, annual precipitation, and runoff will continue to increase and remain synchronously persistent in the future. This work can im-prove the understanding of runoff response to regional climate change to provide a viable reference in the management of water resources in the Kaidu River Basin, a regional sustainable socio-economic development.

  14. Runoff sensitivity to climate change in the Nile River Basin

    Science.gov (United States)

    Hasan, Emad; Tarhule, Aondover; Kirstetter, Pierre-Emmanuel; Clark, Race; Hong, Yang

    2018-06-01

    In data scarce basins, such as the Nile River Basin (NRB) in Africa, constraints related to data availability, quality, and access often complicate attempts to estimate runoff sensitivity using conventional methods. In this paper, we show that by integrating the concept of the aridity index (AI) (derived from the Budyko curve) and climate elasticity, we can obtain the first order response of the runoff sensitivity using minimal data input and modeling expertise or experience. The concept of runoff elasticity relies on the fact that the energy available for evapotranspiration plays a major role in determining whether the precipitation received within a drainage basin generates runoff. The approach does not account for human impacts on runoff modification and or diversions. By making use of freely available gauge-corrected satellite data for precipitation, temperature, runoff, and potential evapotranspiration, we derived the sensitivity indicator (β) to determine the runoff response to changes in precipitation and temperature for four climatic zones in the NRB, namely, tropical, subtropical, semiarid and arid zones. The proposed sensitivity indicator can be partitioned into different elasticity components i.e: precipitation (εp), potential evapotranspiration (εETp), temperature (εT) and the total elasticity (εtot) . These elasticities allow robust quantification of the runoff response to the potential changes in precipitation and temperature with a high degree of accuracy. Results indicate that the tropical zone is energy-constrained with low sensitivity, (β 1.0) . The subtropical-highland zone moves between energy-limited to water-limited conditions during periods of wet and dry spells with varying sensitivity. The semiarid and arid zones are water limited, with high sensitivity, (β > 1.0) . The calculated runoff elasticities show that a 10% decrease in precipitation leads to a decrease in runoff of between 19% in the tropical zone and 30% in the arid zones

  15. Runoff erosion

    OpenAIRE

    Evelpidou, Niki (Ed.); Cordier, Stephane (Ed.); Merino, Agustin (Ed.); Figueiredo, Tomás de (Ed.); Centeri, Csaba (Ed.)

    2013-01-01

    Table of Contents PART I – THEORY OF RUNOFF EROSION CHAPTER 1 - RUNOFF EROSION – THE MECHANISMS CHAPTER 2 - LARGE SCALE APPROACHES OF RUNOFF EROSION CHAPTER 3 - MEASURING PRESENT RUNOFF EROSION CHAPTER 4 - MODELLING RUNOFF EROSION CHAPTER 5 - RUNOFF EROSION AND HUMAN SOCIETIES: THE INFLUENCE OF LAND USE AND MANAGEMENT PRACTICES ON SOIL EROSION PART II - CASE STUDIES CASE STUDIES – INTRODUCTION: RUNOFF EROSION IN MEDITERRANEAN AREA CASE STUDY 1: Soil Erosion Risk...

  16. Possible change on the runoff in the upper Yellow River basin under global climate change

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this study,the characteristics and changing trends of temperature,precipitation,and runoff in the upper Yellow River basin up Tangnag station are analyzed by using hydrological and meteorological data in the past 50 years from observation stations in the basin.Further,in this study,the evolving trend of runoff in the future decades is forecasted in the basin based on the method of suppositional climate scenes combination.The results indicate temperature variation in the basin has an evident positive relation with global warming,and the precipitation variations are quite complicated in the basin because of differences of located geographic positions during the past 50 years.Runoff in the basin has been decreasing continually since the end of the 1980s because the mean temperature in the basin has been rising and precipitation in the main areas of runoff formation in the basin has been decreasing.Runoff will largely decrease if precipitation decreases and temperature rises continuously,whereas runoff will increase if temperature is invariable and precipitation increases largely;the increase magnitude of runoff may be more than that of precipitation because of the synchronously increasing supply of meltwater from snow,glacier,and frozen soils in future several decades.

  17. Runoff changes have a land cover specific effect on the seasonal fluxes of terminal electron acceptors in the boreal catchments.

    Science.gov (United States)

    Mattsson, Tuija; Lehtoranta, Jouni; Ekholm, Petri; Palviainen, Marjo; Kortelainen, Pirkko

    2017-12-01

    Climate change influences the volume and seasonal distribution of runoff in the northern regions. Here, we study how the seasonal variation in the runoff affects the concentrations and export of terminal electron acceptors (i.e. TEAs: NO 3 , Mn, Fe and SO 4 ) in different boreal land-cover classes. Also, we make a prediction how the anticipated climate change induced increase in runoff will alter the export of TEAs in boreal catchments. Our results show that there is a strong positive relationship between runoff and the concentration of NO 3 -N, Mn and Fe in agricultural catchments. In peaty catchments, the relationship is poorer and the concentrations of TEAs tend to decrease with increasing runoff. In forested catchments, the correlation between runoff and TEA concentrations was weak. In most catchments, the concentrations of SO 4 decrease with an increase in runoff regardless of the land cover or season. The wet years export much higher amounts of TEAs than the dry years. In southern agricultural catchments, the wet years increased the TEA export for both spring (January-May) and autumn (September-December) periods, while in the peaty and forested catchments in eastern and northern Finland the export only increased in the autumn. Our predictions for the year 2099 indicate that the export of TEAs will increase especially from agricultural but also from forested catchments. Additionally, the predictions show an increase in the export of Fe and SO 4 for all the catchments for the autumn. Thus, the climate induced change in the runoff regime is likely to alter the exported amount of TEAs and the timing of the export downstream. The changes in the amounts and timing in the export of TEAs have a potential to modify the mineralization pathways in the receiving water bodies, with feedbacks in the cycling of C, nutrients and metals in aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Determination of electron temperature and electron density in ...

    African Journals Online (AJOL)

    It is seen that the electron temperature increases from 5.8 × 102 oK to 7.83 × 104 oK as the pd is reduced from 130mm Hg × mm to 60 mm Hg × mm for argon. The electron densities increases from 2.8 × 1011/cm3 to 3.2 × 1011 /cm3 for the same variation of pds. For air the electron temperature increases from 3.6 × 104 oK to ...

  19. Impacts of climate variability on the runoff in the South Eastern part of Bulgaria

    International Nuclear Information System (INIS)

    Lizama Rivas, Bernardo; Koleva-Lizama, Ivanka

    2004-01-01

    The basic climatic factors, which affect the river runoff, are atmospheric precipitation and temperature. On the basis of the set of data from some hydro-meteorological gauging stations with more than 45 years observations have been studied the effect of meteorological conditions on runoff in the southeastern region of Bulgaria. The change of the temperature, precipitation and runoff over the southeastern Bulgarian catchments are investigated and analyzed. During the application of several statistical tests was found that there are changes in the runoff, which are not caused by the man's activity. The features in the variations of above mentioned hydro-meteorological elements and their inherent trends are determined. The results of this study show that the runoff decreases considerably all over the studied region in the last years. An attempt to find a cause of the changes was done. The significant tendency to gradual reduction of runoff in the region is due to considerably decrease of the precipitation all over the Balkans. The study shows that high temperatures and low precipitation conduct to drought in the region and appears unsuitable conditions for the river runoff feeding and development of plants. (Author)

  20. Electron Bernstein wave electron temperature profile diagnostic (invited)

    International Nuclear Information System (INIS)

    Taylor, G.; Efthimion, P.; Jones, B.; Munsat, T.; Spaleta, J.; Hosea, J.; Kaita, R.; Majeski, R.; Menard, J.

    2001-01-01

    Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either ''overdense,'' operating at high density relative to the magnetic field (e.g., ω pe >>Omega ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (τ>2). Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers as a result of their large k perp . In this article we report on measurements of EBW emission on the CDX-U spherical torus, where B 0 ∼2kG, e >∼10 13 cm -3 and T e ∼10--200eV. Results are presented for electromagnetic measurements of EBW emission, mode converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multipoint Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be ≤T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in the edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where ω pe >>Omega ce

  1. Statistical attribution analysis of the nonstationarity of the annual runoff series of the Weihe River.

    Science.gov (United States)

    Xiong, Lihua; Jiang, Cong; Du, Tao

    2014-01-01

    Time-varying moments models based on Pearson Type III and normal distributions respectively are built under the generalized additive model in location, scale and shape (GAMLSS) framework to analyze the nonstationarity of the annual runoff series of the Weihe River, the largest tributary of the Yellow River. The detection of nonstationarities in hydrological time series (annual runoff, precipitation and temperature) from 1960 to 2009 is carried out using a GAMLSS model, and then the covariate analysis for the annual runoff series is implemented with GAMLSS. Finally, the attribution of each covariate to the nonstationarity of annual runoff is analyzed quantitatively. The results demonstrate that (1) obvious change-points exist in all three hydrological series, (2) precipitation, temperature and irrigated area are all significant covariates of the annual runoff series, and (3) temperature increase plays the main role in leading to the reduction of the annual runoff series in the study basin, followed by the decrease of precipitation and the increase of irrigated area.

  2. Impact of possible climate changes on river runoff under different natural conditions

    Science.gov (United States)

    Gusev, Yeugeniy M.; Nasonova, Olga N.; Kovalev, Evgeny E.; Ayzel, Georgy V.

    2018-06-01

    The present study was carried out within the framework of the International Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) for 11 large river basins located in different continents of the globe under a wide variety of natural conditions. The aim of the study was to investigate possible changes in various characteristics of annual river runoff (mean values, standard deviations, frequency of extreme annual runoff) up to 2100 on the basis of application of the land surface model SWAP and meteorological projections simulated by five General Circulation Models (GCMs) according to four RCP scenarios. Analysis of the obtained results has shown that changes in climatic runoff are different (both in magnitude and sign) for the river basins located in different regions of the planet due to differences in natural (primarily climatic) conditions. The climatic elasticities of river runoff to changes in air temperature and precipitation were estimated that makes it possible, as the first approximation, to project changes in climatic values of annual runoff, using the projected changes in mean annual air temperature and annual precipitation for the river basins. It was found that for most rivers under study, the frequency of occurrence of extreme runoff values increases. This is true both for extremely high runoff (when the projected climatic runoff increases) and for extremely low values (when the projected climatic runoff decreases).

  3. Climatic impacts on the runoff generation processes in British Columbia, Canada

    Directory of Open Access Journals (Sweden)

    A. Loukas

    2002-01-01

    Full Text Available The potential impact of future climate change on runoff generation processes in two southern British Columbia catchments was explored using the Canadian Centre for Climate Modelling Analysis General Circulation Model (CGCMa1 to estimate future changes in precipitation, temperature and cloud cover while the U.B.C. Watershed Model was used to simulate discharges and quantify the separate runoff components, i.e. rainfall, snowmelt, glacier melt and groundwater. Changes, not only in precipitation and temperature but also in the spatial distribution of precipitation with elevation, cloud cover, glacier extension, altitude distribution of vegetation, vegetation biomass production and plant physiology were considered. The future climate of the catchments would be wetter and warmer than the present. In the maritime rain-fed catchment of the Upper Campbell, runoff from rainfall is the most significant source of flow for present and future climatic conditions in the autumn and winter whereas runoff from groundwater generates the flow in spring and summer, especially for the future climate scenario. The total runoff, under the future climatic conditions, would increase in the autumn and winter and decrease in spring and summer. In contrast, in the interior snow-covered Illecillewaet catchment, groundwater is the most significant runoff generation mechanism in the autumn and winter although, at present, significant flow is generated from snowmelt in spring and from glacier runoff in summer. In the future scenario, the contribution to flow from snowmelt would increase in winter and diminish in spring while the runoff from the glacier would remain unchanged; groundwater would then become the most significant source of runoff, which would peak earlier in the season. Keywords: climatic change, hydrological simulation, rainfall, snowmelt, runoff processes

  4. Space-time-frequency analysis of rainfall, runoff and temperature in ...

    African Journals Online (AJOL)

    drinie

    2002-07-03

    Jul 3, 2002 ... from two upstream stations were used to develop a procedure for estimating runoff from the annual .... parts: the basin network under tidal influence and the continental ... Using the power transformation method (Chander.

  5. The Spatiotemporal Variations of Runoff in the Yangtze River Basin under Climate Change

    OpenAIRE

    Xiao, Ziwei; Shi, Peng; Jiang, Peng; Hu, Jianwei; Qu, Simin; Chen, Xingyu; Chen, Yingbing; Dai, Yunqiu; Wang, Jianjin

    2018-01-01

    A better understanding of the runoff variations contributes to a better utilization of water resources and water conservancy planning. In this paper, we analyzed the runoff changes in the Yangtze River Basin (YRB) including the spatiotemporal characteristics of intra-annual variation, the trend, the mutation point, and the period of annual runoff using various statistical methods. We also investigated how changes in the precipitation and temperature could impact on runoff. We found that the i...

  6. The Impact of the Variability of Precipitation and Temperatures on the Efficiency of a Conceptual Rainfall-Runoff Model

    Directory of Open Access Journals (Sweden)

    Sleziak P.

    2016-12-01

    Full Text Available The main objective of the paper is to understand how the model’s efficiency and the selected climatic indicators are related. The hydrological model applied in this study is a conceptual rainfall-runoff model (the TUW model, which was developed at the Vienna University of Technology. This model was calibrated over three different periods between 1981-2010 in three groups of Austrian catchments (snow, runoff, and soil catchments, which represent a wide range of the hydroclimatic conditions of Austria. The model’s calibration was performed using a differential evolution algorithm (Deoptim. As an objective function, we used a combination of the Nash-Sutcliffe coefficient (NSE and the logarithmic Nash-Sutcliffe coefficient (logNSE. The model’s efficiency was evaluated by Volume error (VE. Subsequently, we evaluated the relationship between the model’s efficiency (VE and changes in the climatic indicators (precipitation ΔP, air temperature ΔT. The implications of findings are discussed in the conclusion.

  7. Water Vapor, Temperature and Wind Profiles within Maize Canopy under in-Field Rainwater Harvesting with Wide and Narrow Runoff Strips

    Directory of Open Access Journals (Sweden)

    Weldemichael A. Tesfuhuney

    2013-11-01

    Full Text Available Micrometeorological measurements were used to evaluate heat and water vapor to describe the transpiration (Ev and soil evaporation (Es processes for wide and narrow runoff strips under in-field rainwater harvesting (IRWH system. The resulting sigmoid-shaped water vapor (ea in wide and narrow runoff strips varied in lower and upper parts of the maize canopy. In wide runoff strips, lapse conditions of ea extended from lowest measurement level (LP to the upper middle section (MU and inversion was apparent at the top of the canopy. The virtual potential temperature (θv profile showed no difference in middle section, but the lower and upper portion (UP had lower  in narrow, compared to wide, strips, and LP-UP changes of 0.6 K and 1.2 K were observed, respectively. The Ev and Es within the canopy increased the ea concentration as determined by the wind order of magnitude. The ea concentration reached peak at about 1.6 kPa at a range of wind speed value of 1.4–1.8 m∙s−1 and 2.0–2.4 m∙s−1 for wide and narrow treatments, respectively. The sparse maize canopy of the wide strips could supply more drying power of the air in response to atmospheric evaporative demand compared to narrow strips. This is due to the variation in air flow in wide and narrow runoff strips that change gradients in ea for evapotranspiration processes.

  8. Impacts of the active layer on runoff in an upland permafrost basin, northern Tibetan Plateau.

    Science.gov (United States)

    Gao, Tanguang; Zhang, Tingjun; Guo, Hong; Hu, Yuantao; Shang, Jianguo; Zhang, Yulan

    2018-01-01

    The paucity of studies on permafrost runoff generation processes, especially in mountain permafrost, constrains the understanding of permafrost hydrology and prediction of hydrological responses to permafrost degradation. This study investigated runoff generation processes, in addition to the contribution of summer thaw depth, soil temperature, soil moisture, and precipitation to streamflow in a small upland permafrost basin in the northern Tibetan Plateau. Results indicated that the thawing period and the duration of the zero-curtain were longer in permafrost of the northern Tibetan Plateau than in the Arctic. Limited snowmelt delayed the initiation of surface runoff in the peat permafrost in the study area. The runoff displayed intermittent generation, with the duration of most runoff events lasting less than 24 h. Precipitation without runoff generation was generally correlated with lower soil moisture conditions. Combined analysis suggested runoff generation in this region was controlled by soil temperature, thaw depth, precipitation frequency and amount, and antecedent soil moisture. This study serves as an important baseline to evaluate future environmental changes on the Tibetan Plateau.

  9. Markov-switching model for nonstationary runoff conditioned on El Nino information

    DEFF Research Database (Denmark)

    Gelati, Emiliano; Madsen, H.; Rosbjerg, Dan

    2010-01-01

    We define a Markov-modulated autoregressive model with exogenous input (MARX) to generate runoff scenarios using climatic information. Runoff parameterization is assumed to be conditioned on a hidden climate state following a Markov chain, where state transition probabilities are functions...... of the climatic input. MARX allows stochastic modeling of nonstationary runoff, as runoff anomalies are described by a mixture of autoregressive models with exogenous input, each one corresponding to a climate state. We apply MARX to inflow time series of the Daule Peripa reservoir (Ecuador). El Nino Southern...... Oscillation (ENSO) information is used to condition runoff parameterization. Among the investigated ENSO indexes, the NINO 1+2 sea surface temperature anomalies and the trans-Nino index perform best as predictors. In the perspective of reservoir optimization at various time scales, MARX produces realistic...

  10. Ion- and electron-acoustic solitons in two-electron temperature space plasmas

    International Nuclear Information System (INIS)

    Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

    2008-01-01

    Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

  11. Effects of emitted electron temperature on the plasma sheath

    International Nuclear Information System (INIS)

    Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.

    2014-01-01

    It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03T e /e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux

  12. Observation of electron plasma waves in plasma of two-temperature electrons

    International Nuclear Information System (INIS)

    Ikezawa, Shunjiro; Nakamura, Yoshiharu.

    1981-01-01

    Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

  13. Energy and temperature fluctuations in the single electron box

    International Nuclear Information System (INIS)

    Berg, Tineke L van den; Brange, Fredrik; Samuelsson, Peter

    2015-01-01

    In mesoscopic and nanoscale systems at low temperatures, charge carriers are typically not in thermal equilibrium with the surrounding lattice. The resulting, non-equilibrium dynamics of electrons has only begun to be explored. Experimentally the time-dependence of the electron temperature (deviating from the lattice temperature) has been investigated in small metallic islands. Motivated by these experiments, we investigate theoretically the electronic energy and temperature fluctuations in a metallic island in the Coulomb blockade regime, tunnel coupled to an electronic reservoir, i.e. a single electron box. We show that electronic quantum tunnelling between the island and the reservoir, in the absence of any net charge or energy transport, induces fluctuations of the island electron temperature. The full distribution of the energy transfer as well as the island temperature is derived within the framework of full counting statistics. In particular, the low-frequency temperature fluctuations are analysed, fully accounting for charging effects and non-zero reservoir temperature. The experimental requirements for measuring the predicted temperature fluctuations are discussed. (paper)

  14. Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

    International Nuclear Information System (INIS)

    Xiao-Yuan, Xu; Jun, Wang; Yi, Yu; Yi-Zhi, Wen; Chang-Xuan, Yu; Wan-Dong, Liu; Bao-Nian, Wan; Xiang, Gao; Luhmann, N. C.; Domier, C. W.; Wang, Jian; Xia, Z. G.; Shen, Zuowei

    2009-01-01

    The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number k-bar θ is calculated to be about 1.58 cm −1 , or k-bar θρ s thickapprox 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation. (fluids, plasmas and electric discharges)

  15. A summary of high-temperature electronics research and development

    International Nuclear Information System (INIS)

    Thome, F.V.; King, D.B.

    1991-01-01

    Current and future needs in automative, aircraft, space, military, and well logging industries require operation of electronics at higher temperatures than today's accepted limit of 395 K. Without the availability of high-temperature electronics, many systems must operate under derated conditions or must accept severe mass penalties required by coolant systems to maintain electronic temperatures below critical levels. This paper presents ongoing research and development in the electronics community to bring high-temperature electronics to commercial realization. Much of this work was recently reviewed at the First International High-Temperature Electronics Conference held 16--20 June 1991 in Albuquerque, New Mexico. 4 refs., 1 tab

  16. Attribution analysis of runoff decline in a semiarid region of the Loess Plateau, China

    Science.gov (United States)

    Li, Binquan; Liang, Zhongmin; Zhang, Jianyun; Wang, Guoqing; Zhao, Weimin; Zhang, Hongyue; Wang, Jun; Hu, Yiming

    2018-01-01

    Climate variability and human activities are two main contributing attributions for runoff changes in the Yellow River, China. In the loess hilly-gully regions of the middle Yellow River, water shortage has been a serious problem, and this results in large-scale constructions of soil and water conservation (SWC) measures in the past decades in order to retain water for agricultural irrigation and industrial production. This disturbed the natural runoff characteristics. In this paper, we focused on a typical loess hilly-gully region (Wudinghe and Luhe River basins) and investigated the effects of SWC measures and climate variability on runoff during the period of 1961-2013, while the SWC measures were the main representative of human activities in this region. The nonparametric Mann-Kendall test was used to analyze the changes of annual precipitation, air temperature, potential evapotranspiration (PET), and runoff. The analysis revealed the decrease in precipitation, significant rise in temperature, and remarkable runoff reduction with a rate of more than 0.4 mm per year. It was found that runoff capacity in this region also decreased. Using the change point detection methods, the abrupt change point of annual runoff series was found at 1970, and thus, the study period was divided into the baseline period (1961-1970) and changed period (1971-2013). A conceptual framework based on four statistical runoff methods was used for attribution analysis of runoff decline in the Wudinghe and Luhe River basins (-37.3 and -56.4%, respectively). Results showed that runoff reduction can be explained by 85.2-90.3% (83.3-85.7%) with the SWC measures in the Wudinghe (Luhe) River basin while the remaining proportions were caused by climate variability. The findings suggested that the large-scale SWC measures demonstrated a dominant influence on runoff decline, and the change of precipitation extreme was also a promoting factor of the upward trending of SWC measures' contribution to

  17. Enhancing Seasonal Water Outlooks: Needs and Opportunities in the Critical Runoff Season

    Science.gov (United States)

    Ray, A. J.; Barsugli, J. J.; Yocum, H.; Stokes, M.; Miskus, D.

    2017-12-01

    The runoff season is a critical period for the management of water supply in the western U.S., where in many places over 70% of the annual runoff occurs in the snowmelt period. Managing not only the volume, but the intra-seasonal timing of the runoff is important for optimizing storage, as well as achieving other goals such as mitigating flood risk, and providing peak flows for riparian habitat management, for example, for endangered species. Western river forecast centers produce volume forecasts for western reservoirs that are key input into many water supply decisions, and also short term river forecasts out to 10 days. The early volume forecasts each year typically begin in December, and are updated throughout the winter and into the runoff season (April-July for many areas, but varies). This presentation will discuss opportunities for enhancing this existing suite of RFC water outlooks, including the needs for and potential use for "intraseasonal" products beyond those provided by the Ensemble Streamflow Prediction system and the volume forecasts. While precipitation outlooks have little skill for many areas and seasons, and may not contribute significantly to the outlook, late winter and spring temperature forecasts have meaningful skill in certain areas and sub-seasonal to seasonal time scales. This current skill in CPC temperature outlooks is an opportunity to translate these products into information about the snowpack and potential runoff timing, even where the skill in precipitation is low. Temperature is important for whether precipitation falls as snow or rain, which is critical for streamflow forecasts, especially in the melt season in snowpack-dependent watersheds. There is a need for better outlooks of the evolution of snowpack, conditions influencing the April-July runoff, and the timing of spring peak or shape of the spring hydrograph. The presentation will also discuss a our work with stakeholders of the River Forecast Centers and the NIDIS

  18. Sensitivity of agricultural runoff loads to rising levels of CO2 and climate change in the San Joaquin Valley watershed of California

    International Nuclear Information System (INIS)

    Ficklin, Darren L.; Luo Yuzhou; Luedeling, Eike; Gatzke, Sarah E.; Zhang Minghua

    2010-01-01

    The Soil and Water Assessment Tool (SWAT) was used to assess the impact of climate change on sediment, nitrate, phosphorus and pesticide (diazinon and chlorpyrifos) runoff in the San Joaquin watershed in California. This study used modeling techniques that include variations of CO 2 , temperature, and precipitation to quantify these responses. Precipitation had a greater impact on agricultural runoff compared to changes in either CO 2 concentration or temperature. Increase of precipitation by ±10% and ±20% generally changed agricultural runoff proportionally. Solely increasing CO 2 concentration resulted in an increase in nitrate, phosphorus, and chlorpyrifos yield by 4.2, 7.8, and 6.4%, respectively, and a decrease in sediment and diazinon yield by 6.3 and 5.3%, respectively, in comparison to the present-day reference scenario. Only increasing temperature reduced yields of all agricultural runoff components. The results suggest that agricultural runoff in the San Joaquin watershed is sensitive to precipitation, temperature, and CO 2 concentration changes. - Agricultural runoff is significantly affected by changes in precipitation, temperature, and atmospheric CO 2 concentration.

  19. Mid- and long-term runoff predictions by an improved phase-space reconstruction model

    International Nuclear Information System (INIS)

    Hong, Mei; Wang, Dong; Wang, Yuankun; Zeng, Xiankui; Ge, Shanshan; Yan, Hengqian; Singh, Vijay P.

    2016-01-01

    In recent years, the phase-space reconstruction method has usually been used for mid- and long-term runoff predictions. However, the traditional phase-space reconstruction method is still needs to be improved. Using the genetic algorithm to improve the phase-space reconstruction method, a new nonlinear model of monthly runoff is constructed. The new model does not rely heavily on embedding dimensions. Recognizing that the rainfall–runoff process is complex, affected by a number of factors, more variables (e.g. temperature and rainfall) are incorporated in the model. In order to detect the possible presence of chaos in the runoff dynamics, chaotic characteristics of the model are also analyzed, which shows the model can represent the nonlinear and chaotic characteristics of the runoff. The model is tested for its forecasting performance in four types of experiments using data from six hydrological stations on the Yellow River and the Yangtze River. Results show that the medium-and long-term runoff is satisfactorily forecasted at the hydrological stations. Not only is the forecasting trend accurate, but also the mean absolute percentage error is no more than 15%. Moreover, the forecast results of wet years and dry years are both good, which means that the improved model can overcome the traditional ‘‘wet years and dry years predictability barrier,’’ to some extent. The model forecasts for different regions are all good, showing the universality of the approach. Compared with selected conceptual and empirical methods, the model exhibits greater reliability and stability in the long-term runoff prediction. Our study provides a new thinking for research on the association between the monthly runoff and other hydrological factors, and also provides a new method for the prediction of the monthly runoff. - Highlights: • The improved phase-space reconstruction model of monthly runoff is established. • Two variables (temperature and rainfall) are incorporated

  20. Mid- and long-term runoff predictions by an improved phase-space reconstruction model

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Mei [Research Center of Ocean Environment Numerical Simulation, Institute of Meteorology and oceanography, PLA University of Science and Technology, Nanjing (China); Wang, Dong, E-mail: wangdong@nju.edu.cn [Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, Collaborative Innovation Center of South China Sea Studies, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China); Wang, Yuankun; Zeng, Xiankui [Key Laboratory of Surficial Geochemistry, Ministry of Education, Department of Hydrosciences, School of Earth Sciences and Engineering, Collaborative Innovation Center of South China Sea Studies, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China); Ge, Shanshan; Yan, Hengqian [Research Center of Ocean Environment Numerical Simulation, Institute of Meteorology and oceanography, PLA University of Science and Technology, Nanjing (China); Singh, Vijay P. [Department of Biological and Agricultural Engineering Zachry Department of Civil Engineering, Texas A & M University, College Station, TX 77843 (United States)

    2016-07-15

    In recent years, the phase-space reconstruction method has usually been used for mid- and long-term runoff predictions. However, the traditional phase-space reconstruction method is still needs to be improved. Using the genetic algorithm to improve the phase-space reconstruction method, a new nonlinear model of monthly runoff is constructed. The new model does not rely heavily on embedding dimensions. Recognizing that the rainfall–runoff process is complex, affected by a number of factors, more variables (e.g. temperature and rainfall) are incorporated in the model. In order to detect the possible presence of chaos in the runoff dynamics, chaotic characteristics of the model are also analyzed, which shows the model can represent the nonlinear and chaotic characteristics of the runoff. The model is tested for its forecasting performance in four types of experiments using data from six hydrological stations on the Yellow River and the Yangtze River. Results show that the medium-and long-term runoff is satisfactorily forecasted at the hydrological stations. Not only is the forecasting trend accurate, but also the mean absolute percentage error is no more than 15%. Moreover, the forecast results of wet years and dry years are both good, which means that the improved model can overcome the traditional ‘‘wet years and dry years predictability barrier,’’ to some extent. The model forecasts for different regions are all good, showing the universality of the approach. Compared with selected conceptual and empirical methods, the model exhibits greater reliability and stability in the long-term runoff prediction. Our study provides a new thinking for research on the association between the monthly runoff and other hydrological factors, and also provides a new method for the prediction of the monthly runoff. - Highlights: • The improved phase-space reconstruction model of monthly runoff is established. • Two variables (temperature and rainfall) are incorporated

  1. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  2. Impact of climate variability on runoff in the north-central United States

    Science.gov (United States)

    Ryberg, Karen R.; Lin, Wei; Vecchia, Aldo V.

    2014-01-01

    Large changes in runoff in the north-central United States have occurred during the past century, with larger floods and increases in runoff tending to occur from the 1970s to the present. The attribution of these changes is a subject of much interest. Long-term precipitation, temperature, and streamflow records were used to compare changes in precipitation and potential evapotranspiration (PET) to changes in runoff within 25 stream basins. The basins studied were organized into four groups, each one representing basins similar in topography, climate, and historic patterns of runoff. Precipitation, PET, and runoff data were adjusted for near-decadal scale variability to examine longer-term changes. A nonlinear water-balance analysis shows that changes in precipitation and PET explain the majority of multidecadal spatial/temporal variability of runoff and flood magnitudes, with precipitation being the dominant driver. Historical changes in climate and runoff in the region appear to be more consistent with complex transient shifts in seasonal climatic conditions than with gradual climate change. A portion of the unexplained variability likely stems from land-use change.

  3. Analysis of electron cyclotron emission spectra of high electron temperature, supershot plasmas in TFTR

    International Nuclear Information System (INIS)

    Taylor, G.; Arunasalam, V.; Efthimion, P.C.; Grek, B.

    1993-01-01

    A primary objective of the TFTR program since 1986 has been the study and optimization of deuterium Supershot plasmas. These plasmas are predominantly heated by 90-110 keV neutral deuterium beams (P NBI /P OH >30), central ion temperatures are ∝30 keV and central electron temperatures from ECE (T ECE ) often exceed 10 keV. Central electron temperature data measured with a TV Thomson scattering (TVTS) system (T TVTS ) during the period 1987-1990 have been compared with data from three different ECE instruments on TFTR. Although T ECE ∝T TVTS for temperatures below 6 keV, there is a systematically increasing disagreement at higher electron temperatures, with T ECE ∝1.2 T TVTS for T TVTS in the range 9-10 keV. Recent theoretical work on the ECE radiation temperature of non-equilibrium plasmas indicates that for a bi-Maxwellian electron velocity distribution with a ratio of tail to bulk electron density η, a bulk temperature T b , and a hot tail temperature T h , the perpendicular ECE radiation temperature is given by T ECE ∝T b {1+η(T h /T b )}, for η ECE would be enhanced over T TVTS by a factor which depends on η and T h . This paper investigates whether the discrepancy between T TVTS and T ECE seen in TFTR Supershots at high electron temperatures is due to the presence of a hot electron tail component. The extraordinary mode ECE spectrum at the second, third and fourth harmonics is measured on the horizontal midplane by an absolutely calibrated ECE Michelson interferometer. This ECE spectrum is compared with the output from a time-independent transport code with relativistic opacity which solves the three-dimensional ECE radiation transport in a toroidally symmetric, two-dimensional geometry and uses measured electron density and temperature profiles from the TVTS system. (orig.)

  4. Martian Electron Temperatures in the Sub Solar Region.

    Science.gov (United States)

    Fowler, C. M.; Peterson, W. K.; Andersson, L.; Thiemann, E.; Mayyasi, M.; Yelle, R. V.; Benna, M.; Espley, J. R.

    2017-12-01

    Observations from Viking, and MAVEN have shown that the observed ionospheric electron temperatures are systematically higher than those predicted by many models. Because electron temperature is a balance between heating, cooling, and heat transport, we systematically compare the magnitude of electron heating from photoelectrons, electron cooling and heat transport, as a function of altitude within 30 degrees of the sub solar point. MAVEN observations of electron temperature and density, EUV irradiance, neutral and ion composition are used to evaluate terms in the heat equation following the framework of Matta et al. (Icarus, 2014, doi:10.1016/j.icarus.2013.09.006). Our analysis is restricted to inbound orbits where the magnetic field is within 30 degrees of horizontal. MAVEN sampled the sub solar region in May 2015 and again in May 2017, in near northern spring equinoctial conditions. Solar activity was higher and the spacecraft sampled altitudes down to 120 km in 2015, compared to 160 km in 2017. We find that between 160 and 200 km the Maven electron temperatures are in thermal equilibrium, in the sub solar region, on field lines inclined less than 30 degrees to the horizontal. Above 200km the data suggest that heating from other sources, such as wave heating are significant. Below 160 km some of the discrepancy comes from measurement limitations. This is because the MAVEN instrument cannot resolve the lowest electron temperatures, and because some cooling rates scale as the difference between the electron and neutral temperatures.

  5. Energy-filtered cold electron transport at room temperature.

    Science.gov (United States)

    Bhadrachalam, Pradeep; Subramanian, Ramkumar; Ray, Vishva; Ma, Liang-Chieh; Wang, Weichao; Kim, Jiyoung; Cho, Kyeongjae; Koh, Seong Jin

    2014-09-10

    Fermi-Dirac electron thermal excitation is an intrinsic phenomenon that limits functionality of various electron systems. Efforts to manipulate electron thermal excitation have been successful when the entire system is cooled to cryogenic temperatures, typically distribution corresponds to an effective electron temperature of ~45 K, can be transported throughout device components without external cooling. This is accomplished using a discrete level of a quantum well, which filters out thermally excited electrons and permits only energy-suppressed electrons to participate in electron transport. The quantum well (~2 nm of Cr2O3) is formed between source (Cr) and tunnelling barrier (SiO2) in a double-barrier-tunnelling-junction structure having a quantum dot as the central island. Cold electron transport is detected from extremely narrow differential conductance peaks in electron tunnelling through CdSe quantum dots, with full widths at half maximum of only ~15 mV at room temperature.

  6. Linear and nonlinear characteristics of the runoff response to regional climate factors in the Qira River basin, Xinjiang, Northwest China.

    Science.gov (United States)

    Xue, Jie; Gui, Dongwei

    2015-01-01

    The inland river watersheds of arid Northwest China represent an example of how, in recent times, climatic warming has increased the complexity of Earth's hydrological processes. In the present study, the linear and nonlinear characteristics of the runoff response to temperature and precipitation were investigated in the Qira River basin, located on the northern slope of the Kunlun Mountains. The results showed that average temperature on annual and seasonal scales has displayed a significantly increasing trend, but this has not been reflected in accumulated precipitation and runoff. Using path analysis, a positive link between precipitation and runoff was found both annually and in the summer season. Conversely, it was found that the impact of temperature on runoff has been negative since the 1960s, attributable to higher evaporation and infiltration in the Qira River basin. Over the past 50 years, abrupt changes in annual temperature, precipitation and runoff occurred in 1997, 1987 and 1995, respectively. Combined with analysis using the correlation dimension method, it was found that the temperature, precipitation and runoff, both annually and seasonally, possessed chaotic dynamic characteristics, implying that complex hydro-climatic processes must be introduced into other variables within models to describe the dynamics. In addition, as determined via rescaled range analysis, a consistent annual and seasonal decreasing trend in runoff under increasing temperature and precipitation conditions in the future should be taken into account. This work may provide a theoretical perspective that can be applied to the proper use and management of oasis water resources in the lower reaches of river basins like that of the Qira River.

  7. Study on Variations in Climatic Variables and Their Influence on Runoff in the Manas River Basin, China

    Directory of Open Access Journals (Sweden)

    Lei Ren

    2017-04-01

    Full Text Available Climate change in Northwest China could lead to the change of the hydrological cycle and water resources. This paper assessed the influence of climate change on runoff in the Manas River basin as follows. First, the temporal trends and abrupt change points of runoff, precipitation, and mean, lowest and highest temperature in yearly scale during the period of 1961–2015 were analyzed using the Mann-Kendall (MK test. Then the correlation between runoff and climatic variables was characterized in a monthly, seasonal and yearly scale using the partial correlation method. Furthermore, three global climate models (GCMs from Coupled Model Inter-comparison Project Phase 5 (CMIP5 were bias-corrected using Equidistant Cumulative Distribution Functions (EDCDF method to reveal the future climate change during the period from 2021 to 2060 compared with the baseline period of 1961–2000. The influence of climate change on runoff was studied by simulating the runoff with the GCMs using a modified TOPMODEL considering the future snowmelt during the period from 2021 to 2060. The results showed that the runoff, precipitation, and mean, lowest and highest temperature all presented an increasing trend in yearly scale during the period of 1961–2015, and their abrupt change points were at a similar time; the runoff series was more strongly related to temperature than to precipitation in the spring, autumn and yearly scales, and the opposite was true in winter. All GCMs projected precipitation and temperature, and the runoff simulated with these GCMs were predicted to increase in the period from 2021 to 2060 compared with the baseline period of 1961–2000. These findings provide valuable information for assessing the influence of climate change on water resources in the Manas River basin, and references for water management in such regions.

  8. Estimating Subcatchment Runoff Coefficients using Weather Radar and a Downstream Runoff Sensor

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2013-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage subcatchments based on a combination of high resolution weather radar data and flow measurements from a downstream runoff sensor. By utilising the spatial variability of the precipitation it is possible to estimate...... the runoff coefficients of the separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678 ha) located in the city of Aarhus, Denmark. The study has proven that it is possible to use corresponding measurements of the relative rainfall distribution over...... the catchment and downstream runoff measurements to identify the runoff coefficients at subcatchment level....

  9. Estimating subcatchment runoff coefficients using weather radar and a downstream runoff sensor.

    Science.gov (United States)

    Ahm, Malte; Thorndahl, Søren; Rasmussen, Michael R; Bassø, Lene

    2013-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage subcatchments based on a combination of high resolution weather radar data and flow measurements from a downstream runoff sensor. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients of the separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678 ha) located in the city of Aarhus, Denmark. The study has proven that it is possible to use corresponding measurements of the relative rainfall distribution over the catchment and downstream runoff measurements to identify the runoff coefficients at subcatchment level.

  10. Sensitivity of agricultural runoff loads to rising levels of CO{sub 2} and climate change in the San Joaquin Valley watershed of California

    Energy Technology Data Exchange (ETDEWEB)

    Ficklin, Darren L.; Luo Yuzhou; Luedeling, Eike; Gatzke, Sarah E. [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States); Zhang Minghua, E-mail: mhzhang@ucdavis.ed [Department of Land, Air and Water Resources, University of California, Davis, CA 95616 (United States)

    2010-01-15

    The Soil and Water Assessment Tool (SWAT) was used to assess the impact of climate change on sediment, nitrate, phosphorus and pesticide (diazinon and chlorpyrifos) runoff in the San Joaquin watershed in California. This study used modeling techniques that include variations of CO{sub 2}, temperature, and precipitation to quantify these responses. Precipitation had a greater impact on agricultural runoff compared to changes in either CO{sub 2} concentration or temperature. Increase of precipitation by +-10% and +-20% generally changed agricultural runoff proportionally. Solely increasing CO{sub 2} concentration resulted in an increase in nitrate, phosphorus, and chlorpyrifos yield by 4.2, 7.8, and 6.4%, respectively, and a decrease in sediment and diazinon yield by 6.3 and 5.3%, respectively, in comparison to the present-day reference scenario. Only increasing temperature reduced yields of all agricultural runoff components. The results suggest that agricultural runoff in the San Joaquin watershed is sensitive to precipitation, temperature, and CO{sub 2} concentration changes. - Agricultural runoff is significantly affected by changes in precipitation, temperature, and atmospheric CO{sub 2} concentration.

  11. Temperature dependent electronic conduction in semiconductors

    International Nuclear Information System (INIS)

    Roberts, G.G.; Munn, R.W.

    1980-01-01

    This review describes the temperature dependence of bulk-controlled electronic currents in semiconductors. The scope of the article is wide in that it contrasts conduction mechanisms in inorganic and organic solids and also single crystal and disordered semiconductors. In many experimental situations it is the metal-semiconductor contact or the interface between two dissimilar semiconductors that governs the temperature dependence of the conductivity. However, in order to keep the length of the review within reasonable bounds, these topics have been largely avoided and emphasis is therefore placed on bulk-limited currents. A central feature of electronic conduction in semiconductors is the concentrations of mobile electrons and holes that contribute to the conductivity. Various statistical approaches may be used to calculate these densities which are normally strongly temperature dependent. Section 1 emphasizes the relationship between the position of the Fermi level, the distribution of quantum states, the total number of electrons available and the absolute temperature of the system. The inclusion of experimental data for several materials is designed to assist the experimentalist in his interpretation of activation energy curves. Sections 2 and 3 refer to electronic conduction in disordered solids and molecular crystals, respectively. In these cases alternative approaches to the conventional band theory approach must be considered. For example, the velocities of the charge carriers are usually substantially lower than those in conventional inorganic single crystal semiconductors, thus introducing the possibility of an activated mobility. Some general electronic properties of these materials are given in the introduction to each of these sections and these help to set the conduction mechanisms in context. (orig.)

  12. Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

    Science.gov (United States)

    Yavari, H.; Mokhtari, M.; Bayervand, A.

    2015-03-01

    Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

  13. Deriving the coronal hole electron temperature: electron density dependent ionization / recombination considerations

    International Nuclear Information System (INIS)

    Doyle, John Gerard; Perez-Suarez, David; Singh, Avninda; Chapman, Steven; Bryans, Paul; Summers, Hugh; Savin, Daniel Wolf

    2010-01-01

    Comparison of appropriate theoretically derived line ratios with observational data can yield estimates of a plasma's physical parameters, such as electron density or temperature. The usual practice in the calculation of the line ratio is the assumption of excitation by electrons/protons followed by radiative decay. Furthermore, it is normal to use the so-called coronal approximation, i.e. one only considers ionization and recombination to and from the ground-state. A more accurate treatment is to include ionization/recombination to and from metastable levels. Here, we apply this to two lines from adjacent ionization stages, Mg IX 368 A and Mg X 625 A, which has been shown to be a very useful temperature diagnostic. At densities typical of coronal hole conditions, the difference between the electron temperature derived assuming the zero density limit compared with the electron density dependent ionization/recombination is small. This, however, is not the case for flares where the electron density is orders of magnitude larger. The derived temperature for the coronal hole at solar maximum is around 1.04 MK compared to just below 0.82 MK at solar minimum.

  14. Linear and nonlinear characteristics of the runoff response to regional climate factors in the Qira River basin, Xinjiang, Northwest China

    Directory of Open Access Journals (Sweden)

    Jie Xue

    2015-07-01

    Full Text Available The inland river watersheds of arid Northwest China represent an example of how, in recent times, climatic warming has increased the complexity of Earth’s hydrological processes. In the present study, the linear and nonlinear characteristics of the runoff response to temperature and precipitation were investigated in the Qira River basin, located on the northern slope of the Kunlun Mountains. The results showed that average temperature on annual and seasonal scales has displayed a significantly increasing trend, but this has not been reflected in accumulated precipitation and runoff. Using path analysis, a positive link between precipitation and runoff was found both annually and in the summer season. Conversely, it was found that the impact of temperature on runoff has been negative since the 1960s, attributable to higher evaporation and infiltration in the Qira River basin. Over the past 50 years, abrupt changes in annual temperature, precipitation and runoff occurred in 1997, 1987 and 1995, respectively. Combined with analysis using the correlation dimension method, it was found that the temperature, precipitation and runoff, both annually and seasonally, possessed chaotic dynamic characteristics, implying that complex hydro-climatic processes must be introduced into other variables within models to describe the dynamics. In addition, as determined via rescaled range analysis, a consistent annual and seasonal decreasing trend in runoff under increasing temperature and precipitation conditions in the future should be taken into account. This work may provide a theoretical perspective that can be applied to the proper use and management of oasis water resources in the lower reaches of river basins like that of the Qira River.

  15. On the electron-ion temperature ratio established by collisionless shocks

    Science.gov (United States)

    Vink, Jacco; Broersen, Sjors; Bykov, Andrei; Gabici, Stefano

    2015-07-01

    Astrophysical shocks are often collisionless shocks, in which the changes in plasma flow and temperatures across the shock are established not through Coulomb interactions, but through electric and magnetic fields. An open question about collisionless shocks is whether electrons and ions each establish their own post-shock temperature (non-equilibration of temperatures), or whether they quickly equilibrate in the shock region. Here we provide a simple, thermodynamic, relation for the minimum electron-ion temperature ratios that should be expected as a function of Mach number. The basic assumption is that the enthalpy-flux of the electrons is conserved separately, but that all particle species should undergo the same density jump across the shock, in order for the plasma to remain charge neutral. The only form of additional electron heating that we allow for is adiabatic heating, caused by the compression of the electron gas. These assumptions result in an analytic treatment of expected electron-ion temperature ratio that agrees with observations of collisionless shocks: at low sonic Mach numbers, Ms ≲ 2, the electron-ion temperature ratio is close to unity, whereas for Mach numbers above Ms ≈ 60 the electron-ion temperature ratio asymptotically approaches a temperature ratio of Te/Ti = me/ ⟨ mi ⟩. In the intermediate Mach number range the electron-ion temperature ratio scales as Te/Ti ∝ Ms-2. In addition, we calculate the electron-ion temperature ratios under the assumption of adiabatic heating of the electrons only, which results in a higher electron-ion temperature ratio, but preserves the Te/Ti ∝ Ms-2 scaling. We also show that for magnetised shocks the electron-ion temperature ratio approaches the asymptotic value Te/Ti = me/ ⟨ mi ⟩ for lower magnetosonic Mach numbers (Mms), mainly because for a strongly magnetised shock the sonic Mach number is larger than the magnetosonic Mach number (Mms ≤ Ms). The predicted scaling of the electron

  16. Parametric dependencies of JET electron temperature profiles

    Energy Technology Data Exchange (ETDEWEB)

    Schunke, B [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Imre, K; Riedel, K [New York Univ., NY (United States)

    1994-07-01

    The JET Ohmic, L-Mode and H-Mode electron temperature profiles obtained from the LIDAR Thomson Scattering Diagnostic are parameterized in terms of the normalized flux parameter and a set of the engineering parameters like plasma current, toroidal field, line averages electron density... It is shown that the electron temperature profiles fit a log-additive model well. It is intended to use the same model to predict the profile shape for D-T discharges in JET and in ITER. 2 refs., 5 figs.

  17. Effects of lower hybrid fast electron populations on electron temperature measurements at JET

    International Nuclear Information System (INIS)

    Tanzi, C.P.; Bartlett, D.V.; Schunke, B.

    1993-01-01

    The Lower Hybrid Current Drive (LHCD) system on JET has to date achieved up to 1.5 MA of driven current. This current is carried by a fast electron population with energies more than ten times the electron temperature and density about 10 -4 of the bulk plasma. This paper discusses the effects of this fast electron population on our ability to make reliable temperature measurements using ECE and reviews the effects on other plasma diagnostics which rely on ECE temperature measurements for their interpretation. (orig.)

  18. Impact of Cryosphere Hydrological Changes on the River Runoff in the Tibetan Plateau

    Science.gov (United States)

    Wang, Y.; Yang, D.

    2015-12-01

    The Tibetan Plateau is the headwaters of many major rivers in Asia, the change in streamflow is significant for social and economic development and natural ecology in the middle and lower reaches. Located in the alpine region, streamflow in the plateau is mainly affected by the cryosphere hydrological processes. Due to global warming in recent decades, the Tibetan Plateau is experiencing glaciers shrinking and permafrost degradation. Accelerated glacier melt led to the increasing meltwater, thus affecting the streamflow. Permafrost is an important factor in stabilizing the water cycle and streamflow, the ecological degradation and the significant changes of rivers, lakes, swamps, wetlands and other hydrological environment in recent decades in the Tibetan plateau is closely related to permafrost degradation. Therefore, it is important to explore the impact of cryosphere hydrological changes on the streamflow for the future water management. This study uses a method of base flow separation and a stepwise multiple regression model to investigate the reasons for the runoff changes in different regions of the Tibetan Plateau during 1960-2000. The contribution of glacier melt to annual runoff is particularly estimated to explore the possible influences of soil freezing and thawing on annual runoff changes. The results show an increasing trend of the annual runoff in the upstream of Nujiang River, Lancang River and Qilian Mountains, dominated by the increasing of base flow; and a decreasing trend of the runoff in the upper reach of the Yarlung Zangbo River, Yellow River and Yangtze River, dominated by the reduction of quick flow. Change in the amount of runoff was mainly due to change in precipitation. Rising temperature accelerates the melting of glaciers and increases the summer quick flow. In addition, rising temperature may reduce the quick flow and increase the base flow due to change of the active permafrost layers, which leads to the increase of soil water storage

  19. Climate change and runoff in south-western Australia

    Science.gov (United States)

    Silberstein, R. P.; Aryal, S. K.; Durrant, J.; Pearcey, M.; Braccia, M.; Charles, S. P.; Boniecka, L.; Hodgson, G. A.; Bari, M. A.; Viney, N. R.; McFarlane, D. J.

    2012-12-01

    SummaryThis paper presents the results of computer simulations of runoff from 13 major fresh and brackish river basins in south-western Australia (SWA) under climate projections obtained from 15 GCMs with three future global warming scenarios equivalent to global temperature rises of 0.7 °C, 1.0 °C and 1.3 °C by 2030. The objective was to apply an efficient methodology, consistent across a large region, to examine the implications of the best available projections in climate trends for future surface water resources. An ensemble of rainfall-runoff models was calibrated on stream flow data from 1975 to 2007 from 106 gauged catchments distributed throughout the basins of the study area. The sensitivity of runoff to projected changes in mean annual rainfall is examined using the climate 'elasticity' concept. Averaged across the study area, all 15 GCMs project declines in rainfall under all global warming scenarios with a median decline of 8% resulting in a median decline in runoff of 25%. Such uniformity in projections from GCMs is unusual. Over SWA the average annual runoff under the 5th wettest and 5th driest of the 45 projections of the 2030 climate declines by 10 and 42%, respectively. Under the 5th driest projection the runoff decline ranges from 53% in the northern region to 40% in the southern region. Strong regional variations in climate sensitivity are found with the proportional decline in runoff greatest in the northern region and the greatest volumetric declines in the wetter basins in the south. Since the mid 1970s stream flows into the major water supply reservoirs in SWA have declined by more than 50% following a 16% rainfall reduction. This has already had major implications for water resources planning and for the preservation of aquatic and riparian ecosystems in the region. Our results indicate that this reduction in runoff is likely to continue if future climate projections eventuate.

  20. Modelling runoff and glacier melt in the Hunza basin in northern Pakistan using satellite remote sensing techniques

    International Nuclear Information System (INIS)

    Shafiq, M.

    2011-01-01

    setting, the model computes an increase of 26% and 54% of runoff volume by increasing the temperature by 1 degree C and 2 degree C respectively. For 2003 setting this increase of runoff volume is 22% and 49% by increasing the temperature by 1 degree C and 2 degree C respectively. Assuming a decrease of 1 degree C temperature the model predicts 17% and 22% less runoff volume for 2002 and 2003 settings respectively. Assuming 10% reduction in glacier area, with main retreat at low elevations, the model indicates a decrease of about 18% of runoff volume for both reference cases (for inputs from years 2002 and 2003). The temperature increase by 1 degree C predicts 3.5% more runoff volume for the 2002 setting and 2.7% more runoff volume for the 2003 setting. The increase of temperature with 2 degree C predicts 29% and 27% runoff increase for 2002 and 2003 settings respectively. It is, therefore, concluded that for a mid-term scenario, a decrease of glacier area by 10% would be compensated by increased glacier melt due to warming, resulting in the same or even increased runoff volume as present, depending on the amount of temperature increase. (author)

  1. Anomalous plasma transport due to electron temperature gradient instability

    International Nuclear Information System (INIS)

    Tokuda, Sinji; Ito, Hiroshi; Kamimura, Tetsuo.

    1979-01-01

    The collisionless drift wave instability driven by an electron temperature inhomogeneity (electron temperature gradient instability) and the enhanced transport processes associated with it are studied using a two-and-a-half dimensional particle simulation code. The simulation results show that quasilinear diffusion in phase space is an important mechanism for the saturation of the electron temperature gradient instability. Also, the instability yields particle fluxes toward the hot plasma regions. The heat conductivity of the electron temperature perpendicular to the magnetic field, T sub(e'), is not reduced by magnetic shear but remains high, whereas the heat conductivity of the parallel temperature, T sub(e''), is effectively reduced, and the instability stabilized. (author)

  2. Electron microscopic observation at low temperature on superconductors

    International Nuclear Information System (INIS)

    Yokota, Yasuhiro; Hashimoto, Hatsujiro; Yoshida, Hiroyuki.

    1991-01-01

    The authors have observed superconducting materials with a high resolution electron microscope at liquid helium temperature. First, observation was carried out on Nb system intermetallic compounds such as Nb 3 Al and Nb 3 Sn of Al 5 type and Nb 3 Ge of 11 type at extremely low temperature. Next, the observation of high temperature superconductive ceramics in the state of superconductivity was attempted. In this paper, first the development of the liquid helium sample holder for a 400 kV electron microscope to realize the observation is reported. Besides, the sample holder of Gatan Co. and an extremely low temperature, high resolution electron microscope with a superconducting lens are described. The purpose of carrying out the electron microscope observation of superconductors at low temperature is the direct observation of the crystalline lattice image in the state of superconductivity. Also the structural transformation from tetragonal crystals to rhombic crystals in Al 5 type superconductors can be observed. The results of observation are reported. (K.I.)

  3. 500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

    Science.gov (United States)

    Chen, Liang-yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

    2016-01-01

    High-temperature environment operable sensors and electronics are required for exploring the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high temperature electronics, and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by these high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed. High-temperature environment operable sensors and electronics are required for probing the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and eventual applications of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high electronics and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed.

  4. Effect of two-temperature electrons distribution on an electrostatic plasma sheath

    International Nuclear Information System (INIS)

    Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

    2013-01-01

    A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

  5. Modified electron-acoustic and lower-hybrid drift dissipative instability in a two-electron temperature plasma

    International Nuclear Information System (INIS)

    Bose, M.

    1989-01-01

    It is often found, in fusion devices as well as in the auroral ionosphere, that the electrons consist of two distinct group, viz., hot and cold. These two-temperature electron model is sometimes convenient for analytical purposes. Thus the authors have considered a two-temperature electron plasma. In this paper, they investigated analytically the drift dissipative instabilities of modified electron-acoustic and lower-hybrid wve in a two-electron temperature plasma. It is found that the modified electron-acoustic drift dissipative mode are strongly dependent on the number density of cold electrons. From the expression of the growth rate, it is clear that these cold electrons can control the growth of this mode as well

  6. Potential Formation in Front of an Electron Emitting Electrode in a Two-Electron Temperature Plasma

    International Nuclear Information System (INIS)

    Gyergyek, T.; Cercek, M.; Erzen, D.

    2003-01-01

    Plasma potential formation in the pre-sheath region of a floating electron emitting electrode (collector) is studied theoretically in a two-electron-temperature plasma using a static kinetic plasma-sheath model. Dependence of the collector floating potential, the plasma potential in the pre-sheath region, and the critical emission coefficient on the hot electron density and temperature is calculated. It is found that for high hot to cool electron temperature ratio a double layer like solutions exist in a certain range of hot to cool electron densities

  7. Soils - Potential Runoff

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital spatial data set provides information on the spatial distribution of potential runoff-contributing areas in Kansas. Potential runoff-contributing areas...

  8. Trends and variability in streamflow and snowmelt runoff timing in the southern Tianshan Mountains

    Science.gov (United States)

    Shen, Yan-Jun; Shen, Yanjun; Fink, Manfred; Kralisch, Sven; Chen, Yaning; Brenning, Alexander

    2018-02-01

    Streamflow and snowmelt runoff timing of mountain rivers are susceptible to climate change. Trends and variability in streamflow and snowmelt runoff timing in four mountain basins in the southern Tianshan were analyzed in this study. Streamflow trends were detected by Mann-Kendall tests and changes in snowmelt runoff timing were analyzed based on the winter/spring snowmelt runoff center time (WSCT). Pearson's correlation coefficient was further calculated to analyze the relationships between climate variables, streamflow and WSCT. Annual streamflow increased significantly in past decades in the southern Tianshan, especially in spring and winter months. However, the relations between streamflow and temperature/precipitation depend on the different streamflow generation processes. Annual precipitation plays a vital role in controlling recharge in the Toxkon basin, while the Kaidu and Huangshuigou basins are governed by both precipitation and temperature. Seasonally, temperature has a strong effect on streamflow in autumn and winter, while summer streamflow appears more sensitive to changes in precipitation. However, temperature is the dominant factor for streamflow in the glacierized Kunmalik basin at annual and seasonal scales. An uptrend in streamflow begins in the 1990s at both annual and seasonal scales, which is generally consistent with temperature and precipitation fluctuations. Average WSCT dates in the Kaidu and Huangshuigou basins are earlier than in the Toxkon and Kunmalik basins, and shifted towards earlier dates since the mid-1980s in all the basins. It is plausible that WSCT dates are more sensitive to warmer temperature in spring period compared to precipitation, except for the Huangshuigou basin. Taken together, these findings are useful for applications in flood risk regulation, future hydropower projects and integrated water resources management.

  9. Electron temperature determination in LTE and non-LTE plasmas

    International Nuclear Information System (INIS)

    Eddy, T.L.

    1983-01-01

    This article discusses how most experimental investigations assume a type of ''thermal equilibrium'' in which the excited levels are assumed to be populated according to the electron kinetic temperature, in the determination of electron temperature in LTE and non-LTE plasmas. This is justified on the basis that electron collisions dominate the equilibration of adjacent excited levels as shown by Byron, Stabler and Boartz. The comparison of temperature values calculated by various common methods as a check for local thermodynamic equilibrium (LTDE) or local thermal equilibrium (LTE) of the upper excited levels and the free electrons has been shown to indicate the excitation temperature in all cases utilized. Thomas shows that the source function of the first excited level may be dominated by non-local radiation, which would usually result in a different population than local collisional excitation would provide. Ionization from upper levels is by collisional means. The result may yield different valued excitation and electron temperatures

  10. Responses of snowmelt runoff to climatic change in an inland river basin, Northwestern China, over the past 50 years

    Directory of Open Access Journals (Sweden)

    J. Wang

    2010-10-01

    Full Text Available The spatial and temporal variations of snowcover distribution, and snowmelt runoff are considered as sensitive indicators for climatic change. The purpose of this paper is to analyze and forecast the responses of snowmelt runoff to climate change in an inland river basin. The upper basin of Heihe River in Northwestern China was chose as the study area, and the observation data from the meteorological and hydrological stations were utilized to analyze the status and regularity of the climatic change over the past 50 years. Snow cover area was obtained by an optimized technology using Moderate Resolution Imaging Spectroradiometer data with Normalized Difference Snow Index adjustment and topographic correction. A concept of potential snowmelt was suggested to illustrate the response of spatial snowmelt to climate change. The results show that the annual SCA proportion and the potential snowmelt keep an increasing trend since 2000. There is a negative relationship between annual air temperature and SCA proportion from 2000 to 2008. Snowmelt Runoff Model was chose to simulate snowmelt runoff and scenario forecast the change trend of snowmelt runoff in this region. The results show that climatic warming was apparent in the upper basin of Heihe River over the past 50 a. Annual average air temperature of three different weather stations located in the basin has increased 2.1 °C, 2.6 °C and 2.9 °C respectively from 1956 to present. The snowmelt runoff has increased obviously from 1970 to present. With different warming climate scenarios, the results by using SRM simulating showed that the first occurred time of snowmelt runoff shift ahead and discharge become larger as responses of snowmelt runoff to air temperature increasing, and the influence of temperature rising on average discharge of the whole snow season is not obvious.

  11. Electronic ceramics in high-temperature environments

    International Nuclear Information System (INIS)

    Searcy, A.W.; Meschi, D.J.

    1982-01-01

    Simple thermodynamic means are described for understanding and predicting the influence of temperature changes, in various environments, on electronic properties of ceramics. Thermal gradients, thermal cycling, and vacuum annealing are discussed, as well as the variations of ctivities and solubilities with temperature. 7 refs

  12. Ion emission from laser-produced plasmas with two electron temperatures

    International Nuclear Information System (INIS)

    Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

    1978-01-01

    An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

  13. Development of electron temperature measuring system by silicon drift detector

    International Nuclear Information System (INIS)

    Song Xianying; Yang Jinwei; Liao Min

    2007-12-01

    Soft X-ray spectroscopy with two channels Silicon Drift Detector (SDD) are adopted for electron temperature measuring on HL-2A tokamak in 2005. The working principle, design and first operation of the SDD soft X-ray spectroscopy are introduced. The measuring results of electron temperature are also presented. The results show that the SDD is very good detector for electron temperature measuring on HL-2A tokamak. These will become a solid basic work to establish SDD array for electron temperature profiling. (authors)

  14. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  15. Physicochemical conditions and properties of particles in urban runoff and rivers: Implications for runoff pollution.

    Science.gov (United States)

    Wang, Qian; Zhang, Qionghua; Wu, Yaketon; Wang, Xiaochang C

    2017-04-01

    In this study, to gain an improved understanding of the fate and fractionation of particle-bound pollutants, we evaluated the physicochemical conditions and the properties of particles in rainwater, urban runoff, and rivers of Yixing, a city with a large drainage density in the Taihu Lake Basin, China. Road runoff and river samples were collected during the wet and dry seasons in 2015 and 2016. There were significant differences between the physicochemical conditions (pH, oxidation-reduction potential (ORP), and electroconductivity (EC)) of rainwater, runoff, and rivers. The lowest pH and highest ORP values of rainwater provide the optimal conditions for leaching of particle-bound pollutants such as heavy metals. The differences in the physicochemical conditions of the runoff and rivers may contribute to the redistribution of pollutants between particulate and dissolved phases after runoff is discharged into waterways. Runoff and river particles were mainly composed of silt and clay (runoff particles contained a higher proportion of nano-scale particles (runoff pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Non-equilibrium thermionic electron emission for metals at high temperatures

    Science.gov (United States)

    Domenech-Garret, J. L.; Tierno, S. P.; Conde, L.

    2015-08-01

    Stationary thermionic electron emission currents from heated metals are compared against an analytical expression derived using a non-equilibrium quantum kappa energy distribution for the electrons. The latter depends on the temperature decreasing parameter κ ( T ) , which decreases with increasing temperature and can be estimated from raw experimental data and characterizes the departure of the electron energy spectrum from equilibrium Fermi-Dirac statistics. The calculations accurately predict the measured thermionic emission currents for both high and moderate temperature ranges. The Richardson-Dushman law governs electron emission for large values of kappa or equivalently, moderate metal temperatures. The high energy tail in the electron energy distribution function that develops at higher temperatures or lower kappa values increases the emission currents well over the predictions of the classical expression. This also permits the quantitative estimation of the departure of the metal electrons from the equilibrium Fermi-Dirac statistics.

  17. Decreased runoff response to precipitation, Little Missouri River Basin, northern Great Plains, USA

    Science.gov (United States)

    Griffin, Eleanor R.; Friedman, Jonathan M.

    2017-01-01

    High variability in precipitation and streamflow in the semiarid northern Great Plains causes large uncertainty in water availability. This uncertainty is compounded by potential effects of future climate change. We examined historical variability in annual and growing season precipitation, temperature, and streamflow within the Little Missouri River Basin and identified differences in the runoff response to precipitation for the period 1976-2012 compared to 1939-1975 (n = 37 years in both cases). Computed mean values for the second half of the record showed little change (precipitation, but average annual runoff at the basin outlet decreased by 22%, with 66% of the reduction in flow occurring during the growing season. Our results show a statistically significant (p runoff response to precipitation (runoff ratio). Surface-water withdrawals for various uses appear to account for 1°C increases in January through March, are the dominant driver of the observed decrease in runoff response to precipitation in the Little Missouri River Basin.

  18. Effect of electron temperature on small-amplitude electron acoustic solitary waves in non-planar geometry

    Science.gov (United States)

    Bansal, Sona; Aggarwal, Munish; Gill, Tarsem Singh

    2018-04-01

    Effects of electron temperature on the propagation of electron acoustic solitary waves in plasma with stationary ions, cold and superthermal hot electrons is investigated in non-planar geometry employing reductive perturbation method. Modified Korteweg-de Vries equation is derived in the small amplitude approximation limit. The analytical and numerical calculations of the KdV equation reveal that the phase velocity of the electron acoustic waves increases as one goes from planar to non planar geometry. It is shown that the electron temperature ratio changes the width and amplitude of the solitary waves and when electron temperature is not taken into account,our results completely agree with the results of Javidan & Pakzad (2012). It is found that at small values of τ , solitary wave structures behave differently in cylindrical ( {m} = 1), spherical ( {m} = 2) and planar geometry ( {m} = 0) but looks similar at large values of τ . These results may be useful to understand the solitary wave characteristics in laboratory and space environments where the plasma have multiple temperature electrons.

  19. A glacier runoff extension to the Precipitation Runoff Modeling System

    Science.gov (United States)

    A. E. Van Beusekom; R. J. Viger

    2016-01-01

    A module to simulate glacier runoff, PRMSglacier, was added to PRMS (Precipitation Runoff Modeling System), a distributed-parameter, physical-process hydrological simulation code. The extension does not require extensive on-glacier measurements or computational expense but still relies on physical principles over empirical relations as much as is feasible while...

  20. Observation of electron temperature profile in HL-1M tokamak

    International Nuclear Information System (INIS)

    Cao Jianyong; Xu Deming; Ding Xuantong

    2000-01-01

    The principle and method of the electron temperature measurement by means of electron cyclotron emission (ECE) have been described. Several results under different conditions on HL-1M tokamak have been given. The hollow profile of electron temperature appears in some stages, such as current rising, pellet injection and impurity concentration in the plasma centre. When the bias voltage is applied, the electron temperature profile become steeper. All of the phenomena are related with the transport in plasma centre

  1. High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

    Science.gov (United States)

    Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

    2002-01-01

    It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

  2. SiGe Based Low Temperature Electronics for Lunar Surface Applications

    Science.gov (United States)

    Mojarradi, Mohammad M.; Kolawa, Elizabeth; Blalock, Benjamin; Cressler, John

    2012-01-01

    The temperature at the permanently shadowed regions of the moon's surface is approximately -240 C. Other areas of the lunar surface experience temperatures that vary between 120 C and -180 C during the day and night respectively. To protect against the large temperature variations of the moon surface, traditional electronics used in lunar robotics systems are placed inside a thermally controlled housing which is bulky, consumes power and adds complexity to the integration and test. SiGe Based electronics have the capability to operate over wide temperature range like that of the lunar surface. Deploying low temperature SiGe electronics in a lander platform can minimize the need for the central thermal protection system and enable the development of a new generation of landers and mobility platforms with highly efficient distributed architecture. For the past five years a team consisting of NASA, university and industry researchers has been examining the low temperature and wide temperature characteristic of SiGe based transistors for developing electronics for wide temperature needs of NASA environments such as the Moon, Titan, Mars and Europa. This presentation reports on the status of the development of wide temperature SiGe based electronics for the landers and lunar surface mobility systems.

  3. Solvated electrons at elevated temperatures in different alcohols: Temperature and molecular structure effects

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yu [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Lin, Mingzhang [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.j [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Fu, Haiying; Muroya, Yusa [Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan)

    2010-12-15

    The absorption spectra of solvated electrons in pentanol, hexanol and octanol are measured from 22 to 200, 22 to 175 and 50 to150 {sup o}C, respectively, at a fixed pressure of 15 MPa, using nanosecond pulse radiolysis technique. The results show that the peak positions of the absorption spectra have a red-shift (shift to longer wavelengths) as temperature increases, similar to water and other alcohols. Including the above mentioned data, a compilation of currently available experimental data on the energy of absorption maximum (E{sub max}) of solvated electrons changed with temperature in monohydric alcohols, diols and triol is presented. E{sub max} of solvated electron is larger in those alcohols that have more OH groups at all the temperatures. The molecular structure effect, including OH numbers, OH position and carbon chain length, is investigated. For the primary alcohols with same OH group number and position, the temperature coefficient increases with increase in chain length. For the alcohols with same chain length and OH numbers, temperature coefficient is larger for the symmetric alcohols than the asymmetric ones.

  4. Temperature measurement systems in wearable electronics

    Science.gov (United States)

    Walczak, S.; Gołebiowski, J.

    2014-08-01

    The aim of this paper is to present the concept of temperature measurement system, adapted to wearable electronics applications. Temperature is one of the most commonly monitored factor in smart textiles, especially in sportswear, medical and rescue products. Depending on the application, measured temperature could be used as an initial value of alert, heating, lifesaving or analysis system. The concept of the temperature measurement multi-point system, which consists of flexible screen-printed resistive sensors, placed on the T-shirt connected with the central unit and the power supply is elaborated in the paper.

  5. High-Temperature Electronics: Status and Future Prospects in the 21st Century

    Directory of Open Access Journals (Sweden)

    F. Touati

    2006-12-01

    Full Text Available This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with hightemperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Electric Aircraft and Vehicles necessitating distributed control systems, and environmental protection issues stress the need to use and develop high-temperature electronics. This makes high-temperature electronics a key-enabling technology in the 21st century. Actual applications using high-temperature electronics are discussed in some details. Also information and guidelines are included about supporting electronics needed to make a complete high-temperature system. The technology has been making major advancements and is expected to account for 20% of the electronics market by 2010. However, many technical challenges have to be solved.

  6. Runoff and Evapotranspiration Sensitivities to a Changing Climate in the Western U.S.

    Science.gov (United States)

    Gao, M.; Xiao, M.; Lettenmaier, D. P.

    2017-12-01

    Climate change is likely to alter streamflow seasonal patterns, affect water availability, and otherwise pose challenges to water resources management. It is therefore important to understand how streamflow will respond to changes in climate. Previous studies have mostly focused on runoff sensitivity to precipitation (P) and temperature change, but runoff sensitivity to potential evapotranspiration (PET) is less well understood. In order to investigate how variations in precipitation and PET influence runoff, we conducted both statistical and model-based analyses of 84 near-natural basins in California, Oregon, and Washington. We obtained meteorological forcing data at 1/16 degree spatial resolution for each basin from the University of Washington/UCLA Experimental Surface Water Monitor, and observed runoff data from USGS. For the statistical method, we applied three estimators of the precipitation elasticity of runoff from previous studies. We also estimated the PET elasticity of runoff, using Penman-Monteith reference ET as a surrogate for PET. For the modelling method, we implemented the Sacramento Soil Moisture Accounting (SAC-SMA) Model, where PET is an explicit input. We performed experiments in which we changed P and PET by 1% individually to examine their effects on runoff, from which we computed the P and PET elasticities. We explore the spatial patterns in the elasticities of runoff and their relationships with basin characteristics and climatology. We also evaluate how well the statistical and model-based results meet the complementary relationship posited by Dooge (based on the Budyko Hypothesis) that the precipitation and PET elasticities of annual runoff should sum to one.

  7. MICROWAVE NOISE MEASUREMENT OF ELECTRON TEMPERATURES IN AFTERGLOW PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, Jr., C. C.; McBee, W. D.

    1963-10-15

    Transient electron temperatures in afterglow plasmas were determined for He (5 and 10 torr), Ne, and Ne plus or minus 5% Ar (2.4 and 24 torr) by combining measurements of plasma microwave noise power, and plasma reflectivity and absorptivity. Use of a low-noise parametric preamplifier permitted continuous detection during the afterglow of noise power at 5.5 Bc in a 1 Mc bandwidth. Electron temperature decays were a function of pressure and gas but were slower than predicted by electron energy loss mechanisms. The addition of argon altered the electron density decay in the neon afterglow but the electron temperature decay was not appreciably changed. Resonances in detected noise power vs time in the afterglow were observed for two of the three plasma waveguide geometries studied. These resonances correlate with observed resonances in absorptivity and occur over the same range of electron densities for a given geometry independent of gas type and pressure. (auth)

  8. Estimation of edge electron temperature profiles via forward modelling of the electron cyclotron radiation transport at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Rathgeber, S K; Barrera, L; Eich, T; Fischer, R; Suttrop, W; Wolfrum, E; Nold, B; Willensdorfer, M

    2013-01-01

    We present a method to obtain reliable edge profiles of the electron temperature by forward modelling of the electron cyclotron radiation transport. While for the core of ASDEX Upgrade plasmas, straightforward analysis of electron cyclotron intensity measurements based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin plasma edge needs to consider broadened emission and absorption profiles and radiation transport processes. This is carried out in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different interdependent and complementary diagnostics. By this means, electron cyclotron radiation intensity delivers highly spatially resolved electron temperature data for the plasma edge. In H-mode, the edge gradient of the electron temperature can be several times higher than the one of the radiation temperature. Furthermore, we are able to reproduce the ‘shine-through’ peak—the observation of increased radiation temperatures at frequencies resonant in the optically thin scrape-off layer. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. (paper)

  9. Assessment of runoff contributing catchment areas in rainfall runoff modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Johansen, C.; Schaarup-Jensen, Kjeld

    2006-01-01

    In numerical modelling of rainfall caused runoff in urban sewer systems an essential parameter is the hydrological reduction factor which defines the percentage of the impervious area contributing to the surface flow towards the sewer. As the hydrological processes during a rainfall are difficult...... to determine with significant precision the hydrological reduction factor is implemented to account all hydrological losses except the initial loss. This paper presents an inconsistency between calculations of the hydrological reduction factor, based on measurements of rainfall and runoff, and till now...... recommended literature values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literature values of the hydrological reduction factor are over-estimated for this type of catchment. In addition, different catchment descriptions...

  10. The role of environmental parameter (degree day of snowmelt runoff simulation

    Directory of Open Access Journals (Sweden)

    Ghulam Nabi*, Muhammad Latif, Habib-ur-Rehman and Aftab Hussain Azhar

    2011-04-01

    Full Text Available The upper Indus basin comprises the high mountains covered with snow and glaciers. So the major portion of flowfrom Indus basin is due to snow and glacier melt runoff. The terrain is difficult to measure the hydrological andhydraulics data. Most of the data is available at catchments outlets. Due to the data constraints Snowmelt RunoffModel (SRM was used to estimate the snow melt runoff in Astor basin during, year 2000. The input data includeddaily temperature, precipitation and division of catchment in to different zones on the basis of elevation difference.The elevation zones were made from the Digital Elevation Model (DEM of the area. The snow depletion curveswere made by Landsat TM satellite data analysis on the monthly basis. The model output was dischargehydrograph. The model performance was tested by calculating the statistical parameters such as coefficient ofefficiency (COE and volume difference in percentage. The COE for simulation was 0.91 which illustrates a goodrelationship between simulated and measured values of runoff. The volume difference (Dv for simulation was 9.01.The statistical test showed that model performance was good. The results of SRM model encouraged to usetemperature index approach for snowmelt runoff estimation in Indus basin.

  11. Critical review: Copper runoff from outdoor copper surfaces at atmospheric conditions.

    Science.gov (United States)

    Hedberg, Yolanda S; Hedberg, Jonas F; Herting, Gunilla; Goidanich, Sara; Odnevall Wallinder, Inger

    2014-01-01

    This review on copper runoff dispersed from unsheltered naturally patinated copper used for roofing and facades summarizes and discusses influencing factors, available literature, and predictive models, and the importance of fate and speciation for environmental risk assessment. Copper runoff from outdoor surfaces is predominantly governed by electrochemical and chemical reactions and is highly dependent on given exposure conditions (size, inclination, geometry, degree of sheltering, and orientation), surface parameters (age, patina composition, and thickness), and site-specific environmental conditions (gaseous pollutants, chlorides, rainfall characteristics (amount, intensity, pH), wind direction, temperature, time of wetness, season). The corrosion rate cannot be used to assess the runoff rate. The extent of released copper varies largely between different rain events and is related to dry and wet periods, dry deposition prior to the rain event and prevailing rain and patina characteristics. Interpretation and use of copper runoff data for environmental risk assessment and management need therefore to consider site-specific factors and focus on average data of long-term studies (several years). Risk assessments require furthermore that changes in copper speciation, bioavailability aspects, and potential irreversible retention on solid surfaces are considered, factors that determine the environmental fate of copper runoff from outdoor surfaces.

  12. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    International Nuclear Information System (INIS)

    Liu Qiuyan; Li Hong; Chen Zhipeng; Xie Jinlin; Liu Wandong

    2011-01-01

    Continuous emission spectrum measurement is applied for the inconvenient diagnostics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron temperature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method. (low temperature plasma)

  13. 5 CFR 2422.28 - Runoff elections.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Runoff elections. 2422.28 Section 2422.28... FEDERAL LABOR RELATIONS AUTHORITY REPRESENTATION PROCEEDINGS § 2422.28 Runoff elections. (a) When a runoff may be held. A runoff election is required in an election involving at least three (3) choices, one of...

  14. 29 CFR 102.70 - Runoff election.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Runoff election. 102.70 Section 102.70 Labor Regulations... Runoff election. (a) The regional director shall conduct a runoff election, without further order of the... objections are filed as provided in § 102.69. Only one runoff shall be held pursuant to this section. (b...

  15. Time-resolving electron temperature diagnostic for ALCATOR C

    International Nuclear Information System (INIS)

    Fairfax, S.A.

    1984-05-01

    A diagnostic that provides time-resolved central electron temperatures has been designed, built, and tested on the ALCATOR C Tokamak. The diagnostic uses an array of fixed-wavelength x-ray crystal monochromators to sample the x-ray continuum and determine the absolute electron temperature. The resolution and central energy of each channel were chosen to exclude any contributions from impurity line radiation. This document describes the need for such a diagnostic, the design methodology, and the results with typical ALCATOR C plasmas. Sawtooth (m = 1) temperature oscillations were observed after pellet fueling of the plasma. This is the first time that such oscillations have been observed with an x-ray temperature diagnostic

  16. Thermoluminescence in KBr:D electron irradiated at room temperature

    International Nuclear Information System (INIS)

    Paredes Campoy, J.C.; Lopez Carranza, E.

    1991-07-01

    The thermoluminescence of KBr:D samples electron irradiated at room temperature after thermal annealing at 673 K for 1 hour have been studied in the temperature range 360-730 K. The experimental TL-curve was discomposed by computer analysis in seven overlapping TL peaks, giving for them the order of the kinetics of thermal stimulation, the activation energy, the frequency factor, the relative values of the electronic concentration in traps at the initial heating temperature and the temperature at the maximum of the peak. (author). 18 refs, 1 fig., 3 tabs

  17. Low temperature electron microscopy and electron diffraction of the purple membrane of Halobacterium halobium

    International Nuclear Information System (INIS)

    Hayward, S.B.

    1978-09-01

    The structure of the purple membrane of Halobacterium halobium was studied by high resolution electron microscopy and electron diffraction, primarily at low temperature. The handedness of the purple membrane diffraction pattern with respect to the cell membrane was determined by electron diffraction of purple membranes adsorbed to polylysine. A new method of preparing frozen specimens was used to preserve the high resolution order of the membranes in the electron microscope. High resolution imaging of glucose-embedded purple membranes at room temperature was used to relate the orientation of the diffraction pattern to the absolute orientation of the structure of the bacteriorhodopsin molecule. The purple membrane's critical dose for electron beam-induced damage was measured at room temperature and at -120 0 C, and was found to be approximately five times greater at -120 0 C. Because of this decrease in radiation sensitivity, imaging of the membrane at low temperature should result in an increased signal-to-noise ratio, and thus better statistical definition of the phases of weak reflections. Higher resolution phases may thus be extracted from images than can be determined by imaging at room temperature. To achieve this end, a high resolution, liquid nitrogen-cooled stage was built for the JEOL-100B. Once the appropriate technology for taking low dose images at very high resolution has been developed, this stage will hopefully be used to determine the high resolution structure of the purple membrane

  18. Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster

    International Nuclear Information System (INIS)

    Zhang, Zun; Tang, Haibin; Kong, Mengdi; Zhang, Zhe; Ren, Junxue

    2015-01-01

    Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3

  19. Sheath and heat flow of a two-electron-temperature plasma in the presence of electron emission

    International Nuclear Information System (INIS)

    Sato, Kunihiro; Miyawaki, Fujio

    1992-01-01

    The electrostatic sheath and the heat flow of a two-electron-temperature plasma in the presence of electron emission are investigated analytically. It is shown that the energy flux is markedly enhanced to a value near the electron free-flow energy flux as a result of considerable reduction of the sheath potential due to electron emission if the fraction of hot electrons at the sheath edge is much smaller than one. If the hot- to cold-electron temperature ratio is of the order of ten and the hot electron density is comparable to the cold electron density, the action of the sheath as a thermal insulator is improved as a result of suppression of electron emission due to the space-charge effect of hot electrons. (author)

  20. [Impact of changes in land use and climate on the runoff in Liuxihe Watershed based on SWAT model].

    Science.gov (United States)

    Yuan, Yu-zhi; Zhang, Zheng-dong; Meng, Jin-hua

    2015-04-01

    SWAT model, an extensively used distributed hydrological model, was used to quantitatively analyze the influences of changes in land use and climate on the runoff at watershed scale. Liuxihe Watershed' s SWAT model was established and three scenarios were set. The calibration and validation at three hydrological stations of Wenquan, Taipingchang and Nangang showed that the three factors of Wenquan station just only reached the standard in validated period, and the other two stations had relative error (RE) 0.8 and Nash-Sutcliffe efficiency valve (Ens) > 0.75, suggesting that SWAT model was appropriate for simulating runoff response to land use change and climate variability in Liuxihe watershed. According to the integrated scenario simulation, the annual runoff increased by 11.23 m3 x s(-1) from 2001 to 2010 compared with the baseline period from 1991 to 2000, among which, the land use change caused an annual runoff reduction of 0.62 m3 x s(-1), whereas climate variability caused an annual runoff increase of 11.85 m3 x s(-1). Apparently, the impact of climate variability was stronger than that of land use change. On the other hand, the scenario simulation of extreme land use showed that compared with the land use in 2000, the annual runoff of the farmland scenario and the grassland scenario increased by 2.7% and 0.5% respectively, while that of the forest land scenario were reduced by 0.7%, which suggested that forest land had an ability of diversion closure. Furthermore, the scenario simulation of climatic variability indicated that the change of river runoff correlated positively with precipitation change (increase of 11.6% in annual runoff with increase of 10% in annual precipitation) , but negatively with air temperature change (reduction of 0.8% in annual runoff with increase of 1 degrees C in annual mean air temperature), which showed that the impact of precipitation variability was stronger than that of air temperature change. Therefore, in face of climate

  1. Spot Spraying Reduces Herbicide Concentrations in Runoff.

    Science.gov (United States)

    Melland, Alice R; Silburn, D Mark; McHugh, Allen D; Fillols, Emilie; Rojas-Ponce, Samuel; Baillie, Craig; Lewis, Stephen

    2016-05-25

    Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.

  2. Decrease of non-point zinc runoff using porous concrete.

    Science.gov (United States)

    Harada, Shigeki; Komuro, Yoshinori

    2010-01-01

    The use of porous concrete columns to decrease the amount of zinc in stormwater runoff is examined. The concentration of zinc in a simulated stormwater fluid (zinc acetate solution), fed through concrete columns (slashed circle10x10cm) decreased by 50-81%, suggesting physical adsorption of zinc by the porous concrete. We propose the use of porous concrete columns (slashed circle50x10cm) as the base of sewage traps. Longer-term, high-zinc concentration monitoring revealed that porous concrete blocks adsorb 38.6mgcm(-3) of zinc. A period of no significant zinc runoff (with an acceptable concentration of zinc in runoff of 0.03mgL(-1), a zinc concentration equal to the Japanese Environmental Standard) is estimated for 41years using a 1-ha catchment area with 20 porous concrete sewage traps. Scanning electron microscopy of the porous concrete used in this study indicates that the needle-like particles formed by hydration action significantly increase zinc adsorption. Evidence suggests that the hydrant is ettringite and has an important role in zinc adsorption, the resulting immobilization of zinc and the subsequent effects on groundwater quality. Copyright 2009 Elsevier Ltd. All rights reserved.

  3. Production of a large diameter ECR plasma with low electron temperature

    International Nuclear Information System (INIS)

    Koga, Mayuko; Hishikawa, Yasuhiro; Tsuchiya, Hayato; Kawai, Yoshinobu

    2006-01-01

    A large diameter plasma over 300 mm in diameter is produced by electron cyclotron resonance (ECR) discharges using a cylindrical vacuum chamber of 400 mm in inner diameter. It is found that the plasma uniformity is improved by adding the nitrogen gas to pure Ar plasma. The electron temperature is decreased by adding the nitrogen gas. It is considered that the electron energy is absorbed in the vibrational energy of nitrogen molecules and the electron temperature decreases. Therefore, the adjunction of the nitrogen gas is considered to be effective for producing uniform and low electron temperature plasma

  4. ANN Model-Based Simulation of the Runoff Variation in Response to Climate Change on the Qinghai-Tibet Plateau, China

    Directory of Open Access Journals (Sweden)

    Chang Juan

    2017-01-01

    Full Text Available Precisely quantitative assessments of stream flow response to climatic change and permafrost thawing are highly challenging and urgent in cold regions. However, due to the notably harsh environmental conditions, there is little field monitoring data of runoff in permafrost regions, which has limited the development of physically based models in these regions. To identify the impacts of climate change in the runoff process in the Three-River Headwater Region (TRHR on the Qinghai-Tibet Plateau, two artificial neural network (ANN models, one with three input variables (previous runoff, air temperature, and precipitation and another with two input variables (air temperature and precipitation only, were developed to simulate and predict the runoff variation in the TRHR. The results show that the three-input variable ANN model has a superior real-time prediction capability and performs well in the simulation and forecasting of the runoff variation in the TRHR. Under the different scenarios conditions, the forecasting results of ANN model indicated that climate change has a great effect on the runoff processes in the TRHR. The results of this study are of practical significance for water resources management and the evaluation of the impacts of climatic change on the hydrological regime in long-term considerations.

  5. Can Runoff Responses be Used to Predict Aquatic Biogeochemical Fluxes from Boreal Forest Ecosystems?

    Science.gov (United States)

    Prestegaard, K. L.; Ziegler, S. E.; Billings, S. A.; Edwards, K. A.

    2017-12-01

    Climate change has direct effects on precipitation and temperature, which contribute to indirect changes in ecosystem productivity, runoff, biogeochemical processes, and species composition. In this research, we examine water balances in boreal forest watersheds to determine spatial and inter-annual variations in their responses to changes in precipitation. Our research indicates that Central and Western N. American boreal watersheds with mean annual precipitation (MAP) of less than 1000 mm exhibit positive relationships between annual precipitation and annual evapotranspiration, suggesting an increase in forest productivity during wet years often without increased runoff. In Maritime boreal watersheds in Eastern N. America and N. Europe, runoff is a significantly larger portion of the water balance and runoff increases with precipitation This regionalism in the water balance may have significant consequences for biogeochemical fluxes; for example, where MAP >1000 mm, a future wetter climate may result in increases in the terrestrial-to-aquatic transport of solutes. To test this idea, we examined inter-annual variations in hydrologic and dissolved organic carbon fluxes in watersheds in Newfoundland and Labrador along a longitudinal transect. Mean annual temperature varies from 0-5.2oC along the transect, and MAP varies from 1050 to 1500 mm. Data indicate an increase in evapotranspiration, runoff, and soil DOC fluxes with the increasing mean annual precipitation among watersheds along the transect. During the 2011-2015 period of study there was significant overlap in annual precipitation among the sites. Although wet water years also produced higher amounts of runoff from most watersheds, the annual soil DOC flux within each region was not significantly affected by these inter-annual changes in precipitation. Stream and groundwater monitoring data from the catchments reveal seasonal variations in evapotranspiration and runoff and their role in solute fluxes, and

  6. SPECTROSCOPIC DIAGNOSIS IN ELECTRONIC TEMPERATURE OF PHOTOIONISE PLASMAS

    Directory of Open Access Journals (Sweden)

    A. K. Ferouani

    2015-08-01

    Full Text Available In this work, we are interested in the diagnostics in electronic temperature of a plasma purely photoionized, based on the intensity ration of lines emitted by ions helium-like, which have an atomic number Z relatively small. We considered the three lines corresponding to the transitions starting from the excited levels 1s2l towards the fundamental level 1s2 1S0, like appropriate lines. More precisely, the line of resonance w due to the transition 1s2p 1P1 --- 1s2 1 S0, the line of intercombinaison (x,y 1s2p 3 P2,1 --- 1s2 1 S0  as well as prohibited line z due to the transition 1s2 3 S1 --- 1s2 1 S0. These lines appear clearly in the spectra of astrophysical plasmas. As helium-like ion, we chose two, the oxygen O6+ (Z=8 and neon Ne8+ (Z=10. We carried out calculations of the ration of lines intensity G=(z+x+y/w of O6+ and Ne8+  according to the electronic temperature in the range going from 105 to 107 K. We will see that, like it was shown by Gabriel and Jordan in 1969 [1], this intensity ration can be very sensitive to the temperature electronic and practically independent of the electronic density. Consequently, the ration G can be used to determine in a reliable way the electronic temperature of plasma observed [2].

  7. Wolte 5. low temperature electronics

    International Nuclear Information System (INIS)

    Balestra, F.; Dieudonne, F.; Jomaah, J.

    2002-01-01

    This book present the latest research and development results in advanced materials, technologies, devices, circuits and systems for low temperature electronics. The main themes of the papers are ranging from physics and fundamental aspects, modeling and simulation, to device and circuit design. The topics include advanced process and characterization, novel devices and cryogenic instrumentation. The papers are divided into nine sections, reflecting the main research efforts in different areas: i) deep submicron silicon MOSFETs, ii) alternative MOSFETs (SOI, innovating device architectures), iii) III-V devices, iv) other semiconductor devices (Ge devices, p-n junctions, IR sensors, semiconductor microcrystals), v) emerging devices and phenomena (nano Si-based devices, conduction and fluctuations mechanisms), vi) superconducting materials, vii) superconducting detectors, viii) superconducting devices and circuits (RSFQ, SIS mixers, metal-superconducting-semiconductor structures), ix) low temperature electronics for space applications. Six invited papers presented by internationally recognized authors, and 39 contributed papers are presented. The invited papers provide an excellent overview of today's status and progress, as well as tomorrow's challenges and trends in this important discipline for many cryogenic applications. (authors)

  8. Runoff from armored slopes

    International Nuclear Information System (INIS)

    Codell, R.B.

    1986-01-01

    Models exist for calculating overland flow on hillsides but no models have been found which explicitly deal with runoff from armored slopes. Flow on armored slopes differs from overland flow, because substantial flow occurs beneath the surface of the rock layer at low runnoff, and both above and below the surface for high runoff. In addition to the lack of a suitable model, no estimates of the PMP exist for such small areas and for very short durations. This paper develops a model for calculating runoff from armored embankments. The model considers the effect of slope, drainage area and ''flow concentration'' caused by irregular grading or slumping. A rainfall-duration curve based on the PMP is presented which is suitable for very small drainage areas. The development of the runoff model and rainfall-duration curve is presented below, along with a demonstration of the model on the design of a hypothetical tailings embankment

  9. Coupled ion temperature gradient and trapped electron mode to electron temperature gradient mode gyrokinetic simulations

    International Nuclear Information System (INIS)

    Waltz, R. E.; Candy, J.; Fahey, M.

    2007-01-01

    Electron temperature gradient (ETG) transport is conventionally defined as the electron energy transport at high wave number (high-k) where ions are adiabatic and there can be no ion energy or plasma transport. Previous gyrokinetic simulations have assumed adiabatic ions (ETG-ai) and work on the small electron gyroradius scale. However such ETG-ai simulations with trapped electrons often do not have well behaved nonlinear saturation unless fully kinetic ions (ki) and proper ion scale zonal flow modes are included. Electron energy transport is separated into ETG-ki at high-k and ion temperature gradient-trapped electron mode (ITG/TEM) at low-k. Expensive (more computer-intensive), high-resolution, large-ion-scale flux-tube simulations coupling ITG/TEM and ETG-ki turbulence are presented. These require a high effective Reynolds number R≡[k(max)/k(min)] 2 =μ 2 , where μ=[ρ si /ρ si ] is the ratio of ion to electron gyroradii. Compute times scale faster than μ 3 . By comparing the coupled expensive simulations with (1) much cheaper (less compute-intensive), uncoupled, high-resolution, small, flux-tube ETG-ki and with (2) uncoupled low-resolution, large, flux-tube ITG/TEM simulations, and also by artificially turning ''off'' the low-k or high-k drives, it appears that ITG/TEM and ETG-ki transport are not strongly coupled so long as ETG-ki can access some nonadiabatic ion scale zonal flows and both high-k and low-k are linearly unstable. However expensive coupled simulations are required for physically accurate k-spectra of the transport and turbulence. Simulations with μ≥30 appear to represent the physical range μ>40. ETG-ki transport measured in ion gyro-Bohm units is weakly dependent on μ. For the mid-radius core tokamak plasma parameters studied, ETG-ki is about 10% of the electron energy transport, which in turn is about 30% of the total energy transport (with negligible ExB shear). However at large ExB shear sufficient to quench the low-k ITG

  10. Assessment of Runoff Contributing Catchment Areas in Rainfall Runoff Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Johansen, C.; Schaarup-Jensen, Kjeld

    2005-01-01

    to determine with significant precision the hydrological reduction factor is implemented to account all hydrological losses except the initial loss. This paper presents an inconsistency between calculations of the hydrological reduction factor, based on measurements of rainfall and runoff, and till now...... recommended literary values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literary values of the hydrological reduction factor are over-estimated for this type of catchments. In addition, different catchment descriptions...

  11. Improving runoff risk estimates: Formulating runoff as a bivariate process using the SCS curve number method

    Science.gov (United States)

    Shaw, Stephen B.; Walter, M. Todd

    2009-03-01

    The Soil Conservation Service curve number (SCS-CN) method is widely used to predict storm runoff for hydraulic design purposes, such as sizing culverts and detention basins. As traditionally used, the probability of calculated runoff is equated to the probability of the causative rainfall event, an assumption that fails to account for the influence of variations in soil moisture on runoff generation. We propose a modification to the SCS-CN method that explicitly incorporates rainfall return periods and the frequency of different soil moisture states to quantify storm runoff risks. Soil moisture status is assumed to be correlated to stream base flow. Fundamentally, this approach treats runoff as the outcome of a bivariate process instead of dictating a 1:1 relationship between causative rainfall and resulting runoff volumes. Using data from the Fall Creek watershed in western New York and the headwaters of the French Broad River in the mountains of North Carolina, we show that our modified SCS-CN method improves frequency discharge predictions in medium-sized watersheds in the eastern United States in comparison to the traditional application of the method.

  12. Temperature gradient driven electron transport in NSTX and Tore Supra

    International Nuclear Information System (INIS)

    Horton, W.; Wong, H.V.; Morrison, P.J.; Wurm, A.; Kim, J.H.; Perez, J.C.; Pratt, J.; Hoang, G.T.; LeBlanc, B.P.; Ball, R.

    2005-01-01

    Electron thermal fluxes are derived from the power balance for Tore Supra (TS) and NSTX discharges with centrally deposited fast wave electron heating. Measurements of the electron temperature and density profiles, combined with ray tracing computations of the power absorption profiles, allow detailed interpretation of the thermal flux versus temperature gradient. Evidence supporting the occurrence of electron temperature gradient turbulent transport in the two confinement devices is found. With control of the magnetic rotational transform profile and the heating power, internal transport barriers are created in TS and NSTX discharges. These partial transport barriers are argued to be a universal feature of transport equations in the presence of invariant tori that are intrinsic to non-monotonic rotational transforms in dynamical systems

  13. Study on Water Quality of Surface Runoff and Groundwater Runoff on the Basis of Separation by a Numerical Filter

    OpenAIRE

    Kawara, Osami; Fukumoto, Kohji

    1994-01-01

    In this study we investigated the water quality of surface runoff and groundwater runoff from the basins of the Yodo River and the Asahi River based on that separated by a numerical filter. The water quality of the surface runoff is greatly different from the groundwater runoff. The tendency of concentration change in accordance with river discharges is different from each other. The water qtiality of groundwater runoff changes with river discharges clockwise in many cases. The differences of...

  14. Room temperature Compton profiles of conduction electrons in α-Ga ...

    Indian Academy of Sciences (India)

    Room temperature Compton profiles of momentum distribution of conduction electrons in -Ga metal are calculated in band model. For this purpose, the conduction electron wave functions are determined in a temperature-dependent non-local model potential. The profiles calculated along the crystallographic directions, ...

  15. Determining coronal electron temperatures from observations with UVCS/SOHO

    Science.gov (United States)

    Fineschi, S.; Esser, R.; Habbal, S. R.; Karovska, M.; Romoli, M.; Strachan, L.; Kohl, J. L.; Huber, M. C. E.

    1995-01-01

    The electron temperature is a fundamental physical parameter of the coronal plasma. Currently, there are no direct measurements of this quantity in the extended corona. Observations with the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the upcoming Solar and Heliospheric Observatory (SOHO) mission can provide the most direct determination of the electron kinetic temperature (or, more precisely, the electron velocity distribution along the line of sight). This measurement is based on the observation of the Thomson-scattered Lyman alpha (Ly-alpha) profile. This observation is made particularly challenging by the fact that the integrated intensity of the electron-scattered Ly-alpha line is about 10(exp 3) times fainter than that of the resonantly-scattered Ly-alpha component. In addition, the former is distributed across 50 A (FWHM), unlike the latter that is concentrated in 1 A. These facts impose stringent requirements on the stray-light rejection properties of the coronagraph/spectrometer, and in particular on the requirements for the grating. We make use of laboratory measurements of the UVCS Ly-alpha grating stray-light, and of simulated electron-scattered Ly-alpha profiles to estimate the expected confidence levels of electron temperature determination. Models of different structures typical of the corona (e.g., streamers, coronal holes) are used for this parameter study.

  16. ISLSCP II UNH/GRDC Composite Monthly Runoff

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The University of New Hampshire (UNH)/Global Runoff Data Centre (GRDC) composite runoff data combines simulated water balance model runoff estimates...

  17. Experimental study of water absorption of electronic components and internal local temperature and humidity into electronic enclosure

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in large spans of temperature and humidity during day and night shifts. Corrosion failures are still seen due to the effects of temperature, humidity......, differential humidity, and temperature effects simulating day/night, and the use of desiccants....

  18. ELECTRON ENERGY DECAY IN HELIUM AFTERGLOW PLASMAS AT CRYOGENIC TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Goldan, P. D.; Cahn, J. H.; Goldstein, L.

    1963-10-15

    Studies of decaying afterglow plasmas in helium were ined near 4 deg K by immersion in a liquid helium bath. By means of a Maser Radiometer System, the electron temperature was followed below 200 deg K. Guided microwave propagation and wave interaction techniques premit determination of election number density and collision frequencies for momentum transfer. Electron temperature decay rates of the order of 150 mu sec/p(mm Hg alpha 4.2 deg K) were found. Since thermal relaxation by elastic collisions should be some two orders of magnitude faster than this, the electrons appear to be in quasiequilibrium with a slowly decaying internal heating source. Correlation of the expected decay rates of singlet metastable helium atoms with the electron temperature decay gives good agreement with the present experiment. (auth)

  19. Effects of IPCC SRES* emissions scenarios on river runoff: a global perspective

    Directory of Open Access Journals (Sweden)

    N. W. Arnell

    2003-01-01

    mild climates, higher temperatures mean that peak streamflow moves from spring to winter as less winter precipitation falls as snow. The spatial pattern of changes in the 10-year return period maximum monthly runoff follows changes in annual runoff. Keywords: SRES emissions scenarios, climate change impacts on runoff, multi-decadal variability, macro-scale hydrological model, drought frequency, flood frequency

  20. Calculating the electron temperature in the lightning channel by continuous spectrum

    Science.gov (United States)

    Xiangcheng, DONG; Jianhong, CHEN; Xiufang, WEI; Ping, YUAN

    2017-12-01

    Based on the theory of plasma continuous radiation, the relationship between the emission intensity of bremsstrahlung and recombination radiation and the plasma electron temperature is obtained. During the development process of a return stroke of ground flash, the intensity of continuous radiation spectrum is separated on the basis of the spectrums with obviously different luminous intensity at two moments. The electron temperature of the lightning discharge channel is obtained through the curve fitting of the continuous spectrum intensity. It is found that electron temperature increases with the increase of wavelength and begins to reduce after the peak. The peak temperature of the two spectra is close to 25 000 K. To be compared with the result of discrete spectrum, the electron temperature is fitted by the O I line and N II line of the spectrum respectively. The comparison shows that the high temperature value is in good agreement with the temperature of the lightning core current channel obtained from the ion line information, and the low temperature at the high band closes to the calculation result of the atomic line, at a low band is lower than the calculation of the atomic line, which reflects the temperature of the luminous channel of the outer corona.

  1. The effect of the runoff size on the pesticide concentration in runoff water and in FOCUS streams simulated by PRZM and TOXSWA.

    Science.gov (United States)

    Adriaanse, Paulien I; Van Leerdam, Robert C; Boesten, Jos J T I

    2017-04-15

    Within the European Union the exposure of aquatic organisms to pesticides is assessed by simulations with the so-called FOCUS Surface Water Scenarios. Runoff plays an important role in these scenarios. As little is known about the effect of runoff size on the exposure, we investigated the effect of runoff size on the concentration in the runoff water and in streams simulated with the PRZM and TOXSWA models for two FOCUS runoff scenarios. For weakly sorbing pesticides (K F,oc runoff water decreased exponentially with increasing daily runoff size. The runoff size hardly affected the pesticide concentration in the runoff water of strongly sorbing pesticides (K F,oc ≥1000Lkg -1 ). For weakly sorbing pesticides the concentration in the FOCUS stream reached a maximum at runoff sizes of about 0.3 to 1mm. The concentration increased rapidly when the runoff size increased from 0 to 0.1mm and gradually decreased when runoff exceeded 1mm. For strongly sorbing pesticides the occurrence of the maximum concentration in the stream is clearly less pronounced and lies approximately between 1 and 20mm runoff. So, this work indicates that preventing small runoff events (e.g. by vegetated buffer strips) reduces exposure concentrations strongly for weakly sorbing pesticides. A simple metamodel was developed for the ratio between the concentrations in the stream and in the runoff water. This model predicted the ratios simulated by TOXSWA very well and it demonstrated that (in addition to runoff size and concentration in runoff) the size of the pesticide-free base flow and pesticide treatment ratio of the catchment determine the stream concentration to a large extent. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Electron temperature measurement in Z-pinch

    International Nuclear Information System (INIS)

    Gerusov, A.V.; Orlov, M.M.; Terent'ev, A.R.; Khrabrov, V.A.

    1987-01-01

    Measurement of temperature of emitting plasma sheath in noncylindrical Z-pinch in neon at the stage of convergence to the axis, based on comparing the intensity of spectral lines belonging to Ne1, Ne2, is performed. Line intensity relation dependence was determined using calculations according to emitting-collision model. Spectra were recorded by electron-optical converter and relative intensity was determined by subsequent photometry of photolayer. Cylindric symmetrical MHD-calculations during which temperature and the observed line intensity relation were determined, are conducted

  3. Time focused measurements of roof runoff quality

    International Nuclear Information System (INIS)

    Schriewer, A.; Horn, H.; Helmreich, B.

    2008-01-01

    Runoff properties and their changes during runoff of a 14 year old zinc roof were investigated. Zinc, lead, cadmium, pH value, rain intensity and electric conductivity have been measured for a period of one year. A runoff rate of 3.73 g/m 2 a and a volume weighted mean zinc concentration of 4.9 mg/L were determined. First flush behaviour was observed in 93% of runoff events. Low rain intensities are correlating with higher zinc concentrations in runoff, whereas the duration of antecedent dry periods could not directly be linked with initial zinc concentrations

  4. Evaluation of COTS Electronic Parts for Extreme Temperature Use in NASA Missions

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Electronic systems capable of extreme temperature operation are required for many future NASA space exploration missions where it is desirable to have smaller, lighter, and less expensive spacecraft and probes. Presently, spacecraft on-board electronics are maintained at about room temperature by use of thermal control systems. An Extreme Temperature Electronics Program at the NASA Glenn Research Center focuses on development of electronics suitable for space exploration missions. The effects of exposure to extreme temperatures and thermal cycling are being investigated for commercial-off-the-shelf components as well as for components specially developed for harsh environments. An overview of this program along with selected data is presented.

  5. Assessing the response of runoff to climate change and human activities for a typical basin in the Northern Taihang Mountain, China

    Science.gov (United States)

    Wang, Jinfeng; Gao, Yanchuan; Wang, Sheng

    2018-04-01

    Climate change and human activities are the two main factors on runoff change. Quantifying the contribution of climate change and human activities on runoff change is important for water resources planning and management. In this study, the variation trend and abrupt change point of hydro-meteorological factors during 1960-2012 were detected by using the Mann-Kendall test and Pettitt change-point statistics. Then the runoff was simulated by SWAT model. The contribution of climate change and human activities on runoff change was calculated based on the SWAT model and the elasticity coefficient method. The results showed that in contrast to the increasing trend for annual temperature, the significant decreasing trends were detected for annual runoff and precipitation, with an abrupt change point in 1982. The simulated results of SWAT had good consistency with observed ones, and the values of R2 and E_{NS} all exceeded 0.75. The two methods used for assessing the contribution of climate change and human activities on runoff reduction yielded consistent results. The contribution of climate change (precipitation reduction and temperature rise) was {˜ }37.5%, while the contribution of human activities (the increase of economic forest and built-up land, hydrologic projects) was {˜ }62.5%.

  6. High-Temperature Electronics: Status and Future Prospects in the 21st Century

    OpenAIRE

    F. Touati; F. Mnif; A. Lawati

    2006-01-01

    This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with hightemperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Elec...

  7. ArcCN-Runoff: An ArcGIS tool for generating curve number and runoff maps

    Science.gov (United States)

    Zhan, X.; Huang, M.-L.

    2004-01-01

    The development and the application of ArcCN-Runoff tool, an extension of ESRI@ ArcGIS software, are reported. This tool can be applied to determine curve numbers and to calculate runoff or infiltration for a rainfall event in a watershed. Implementation of GIS techniques such as dissolving, intersecting, and a curve-number reference table improve efficiency. Technical processing time may be reduced from days, if not weeks, to hours for producing spatially varied curve number and runoff maps. An application example for a watershed in Lyon County and Osage County, Kansas, USA, is presented. ?? 2004 Elsevier Ltd. All rights reserved.

  8. Electron temperature measurement of tungsten inert gas arcs

    International Nuclear Information System (INIS)

    Tanaka, Manabu; Tashiro, Shinichi

    2008-01-01

    In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

  9. Effect of re-heating on the hot electron temperature

    International Nuclear Information System (INIS)

    Estabrook, K.; Rosen, M.

    1980-01-01

    Resonant absorption is the direct conversion of the transverse laser light to longitudinal electron plasma waves (epw) at the critical density [10 21 (1.06 μm/lambda 0 ) 2 cm -3 ]. The oscillating longitudinal electric field of the epw heats the electrons by accelerating them down the density gradient to a temperature of approximately 21T/sub e/ 0 25 ([I(W/cm 2 )/10 16 ](lambda 0 /1.06 μm) 2 ) 0 4 . This section extends the previous work by studying the effects of magnetic fields and collisions (albedo) which return the heated electrons for further heating. A magnetic field increases their temperature and collisions do not

  10. Temperature dependence of electron mean free path in molybdenum from ultrasonic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Almond, D P; Detwiler, D A; Rayne, J A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)

    1975-09-08

    The temperature dependence of the electronic mean free path in molybdenum has been obtained from ultrasonic attenuation measurements.For temperature up to 30 K a T/sup -2/ law is followed suggesting the importance of electron-electron scattering in the attenuation mechanism.

  11. Runoff and soil loss from bench terraces. 1. An event-based model of rainfall infiltration and surface runoff.

    NARCIS (Netherlands)

    van Dijk, A.I.J.M.; Bruijnzeel, L.A.

    2004-01-01

    Overland flow resulting from an excess of rain over infiltration is an essential component of many models of runoff and erosion from fields or catchments. The spatially variable infiltration (SVI) model and a set of associated equations relating depth of runoff and maximum rate of 'effective' runoff

  12. Climate Change Impacts on Runoff Regimes at a River Basin Scale in Central Vietnam

    Directory of Open Access Journals (Sweden)

    Do Hoai Nam

    2012-01-01

    Full Text Available Global warming has resulted in significant variability of global climate especially with regard to variation in temperature and precipitation. As a result, it is expected that river flow regimes will be accordingly varied. This study presents a preliminary projection of medium-term and long-term runoff variation caused by climate change at a river basin scale. The large scale precipitation projection at the middle and the end of the 21st century under the A1B scenario simulated by the CGCM model (MRI & JMA, 300 km resolution is statistically downscaled to a basin scale and then used as input for the super-tank model for runoff analysis at the upper Thu Bon River basin in Central Vietnam. Results show that by the middle and the end of this century annual rainfall will increase slightly; together with a rising temperature, potential evapotranspiration is also projected to increase as well. The total annual runoff, as a result, is found to be not distinctly varied relative to the baseline period 1981 - 2000; however, the runoff will decrease in the dry season and increase in the rainy season. The results also indicate the delay tendency of the high river flow period, shifting from Sep-Dec at present to Oct-Jan in the future. The present study demonstrates potential impacts of climate change on streamflow regimes in attempts to propose appropriate adaptation measures and responses at the river basin scales.

  13. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    Science.gov (United States)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-07-01

    Both the semi-classical and quantum transport properties of F-doped SnO2 thick films (˜1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ˜90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  14. Linear temperature behavior of thermopower and strong electron-electron scattering in thick F-doped SnO2 films

    International Nuclear Information System (INIS)

    Lang, Wen-Jing; Li, Zhi-Qing

    2014-01-01

    Both the semi-classical and quantum transport properties of F-doped SnO 2 thick films (∼1 μm) were investigated experimentally. We found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from ∼90 to 300 K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10 K, can be observed. The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the fact that the carrier concentration has negligible temperature dependence, indicate that the conduction electrons in F-doped SnO 2 films possess free-electron-like characteristics. At low temperatures, the electron-electron scattering dominates over the electron-phonon scattering and governs the inelastic scattering process. The theoretical predications of scattering rates of large- and small-energy-transfer electron-electron scattering processes, which are negligibly weak in three-dimensional disordered conventional conductors, are quantitatively tested in this lower carrier concentration and free-electron-like highly degenerate semiconductor.

  15. Rainfall-runoff modelling of the Okavango River catchment to assess impacts of land use change on runoff and downstream ecosystems

    Science.gov (United States)

    Milzow, Christian; Bauer-Gottwein, Peter

    2010-05-01

    The competition between human water use and ecosystem water use is one of the major challenges for water resources management at the global scale. We analyse the situation for the Okavango River basin of southern Africa. The Okavango River is representative for many large rivers throughout the developing world in that it is ungauged and poorly studied. The Okavango basin - spanning over Angola, Namibia and Botswana - represents a multi-objective problem in an international setting. Economic benefits of agricultural development and conservation of ecosystem services call for opposed actions. A semi-distributed rainfall-runoff model of the Okavango catchment is set up using the Soil and Water Assessment Tool (SWAT). The model is sufficiently physically based to simulate the impact on runoff of extent of agricultural use, crop types and management practices. Precipitation and temperature inputs are taken from datasets covering large parts of the globe. The methodology can thus easily be applied for other ungauged catchments. For temperature we use the ERA-Interim reanalysis product of the European Centre for Medium-Range Weather Forecasts and for precipitation the Famine Early Warning Systems Network data (FEWS-Net). Tropical Rainfall Measurement Mission (TRMM) data resulted in poor model performance compared to the FEWS-Net data. Presently, the upstream catchment in Angola is largely pristine and agriculture is basically restricted to dry land subsistence farming. But economic growth in Angola is likely to result in agricultural development and consequent impacts on catchment runoff. Land use scenarios that are simulated include large scale irrigated agriculture with water extractions from the river and the shallow aquifer. Climate change impacts are also studied and compared to land use change impacts. The downstream part of the basin consists of the large Okavango Wetlands, which are a biodiversity hotspot of global importance and, through tourism, an important

  16. RUNOFF POTENTIAL OF MUREŞ RIVER UPPER BASIN TRIBUTARIES

    Directory of Open Access Journals (Sweden)

    V. SOROCOVSCHI

    2012-03-01

    Full Text Available Runoff Potential of Mureş River Upper Basin Tributaries. The upper basin of the Mureş River includes a significant area of the Eastern Carpathians central western part with different runoff formation conditions. In assessing the average annual runoff potential we used data from six gauging stations and made assessments on three distinct periods. Identifying the appropriate areas of the obtained correlations curves (between specific average runoff and catchments mean altitude allowed the assessment of potential runoff at catchment level and on geographical units. The potential average runoff is also assessed on altitude intervals of the mentioned areas. The runoff potential analysis on hydrographic basins, geographical units and altitude intervals highlights the variant spatial distribution of this general water resources indicator in the different studied areas.

  17. Whistler waves with electron temperature anisotropy and non-Maxwellian distribution functions

    Directory of Open Access Journals (Sweden)

    M. Usman Malik

    2018-05-01

    Full Text Available The previous works on whistler waves with electron temperature anisotropy narrated the dependence on plasma parameters, however, they did not explore the reasons behind the observed differences. A comparative analysis of the whistler waves with different electron distributions has not been made to date. This paper attempts to address both these issues in detail by making a detailed comparison of the dispersion relations and growth rates of whistler waves with electron temperature anisotropy for Maxwellian, Cairns, kappa and generalized (r, q distributions by varying the key plasma parameters for the problem under consideration. It has been found that the growth rate of whistler instability is maximum for flat-topped distribution whereas it is minimum for the Maxwellian distribution. This work not only summarizes and complements the previous work done on the whistler waves with electron temperature anisotropy but also provides a general framework to understand the linear propagation of whistler waves with electron temperature anisotropy that is applicable in all regions of space plasmas where the satellite missions have indicated their presence.

  18. Room Temperature Deposition Processes Mediated By Ultrafast Photo-Excited Hot Electrons

    Science.gov (United States)

    2014-01-30

    mechanical through resonant energy transfer. The average electron temperature (Tel) during τ2 evolves as energy is lost through optical and acoustic ...through ballistic collisions and acoustic phonons. The large difference in heat capacities between electrons and the substrate leads to negligible...temperature pyrometer indicated only a ~30oC temperature gradient between the thermocouple location and the topside of the sample which faced the

  19. Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

    International Nuclear Information System (INIS)

    Tamura, N.; Inagaki, S.; Tokuzawa, T.

    2006-10-01

    Edge cooling experiments with a tracer-encapsulated solid pellet in the Large Helical Device (LHD) show a significant rise of core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport is dominated. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay of the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase in collisionality in the core plasma and the decrease in electron temperature gradient scale length in the outer region of the plasma. (author)

  20. Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

    International Nuclear Information System (INIS)

    Tamura, N.; Inagaki, S.; Tanaka, K.; Michael, C.; Tokuzawa, T.; Shimozuma, T.; Kubo, S.; Sakamoto, R.; Ida, K.; Itoh, K.; Kalinina, D.; Sudo, S.; Nagayama, Y.; Kawahata, K.; Komori, A.

    2007-01-01

    Edge cooling experiments with a tracer-encapsulated solid pellet in the large helical device (LHD) show a significant rise in core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport dominates. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay in the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase both in the collisionality in the core plasma and the electron temperature gradient scale length in the outer region of the plasma

  1. Electron temperature from x-ray continuum measurements on the NIF

    Science.gov (United States)

    Jarrott, Leonard; Bachmann, Benjamin; Benedetti, Robin; Izumi, Nobuhiko; Khan, Shahab; Landen, Otto; Ma, Tammy; Nagel, Sabrina; Pak, Arthur; Patel, Prav; Schneider, Marilyn; Springer, Paul; LLNL Collaboration

    2017-10-01

    We report on measurements of the electron temperature within the hot spot of inertially confined, layered implosions on the NIF using a titanium differential filtering x-ray diagnostic. The electron temperature from x-ray emission is insensitive to non-thermal velocity flows as is the case with ion temperature measurements and is thus a critical parameter in interpreting stagnated hot spot conditions. Here we discuss measurements using titanium filters ranging from 10 μm to 1mm in thickness with a sensitivity band of 10-30keV coupled with penumbral pinholes. The use of larger pinhole diameters increases x-ray fluence improving sensitivity of photon energies with minimal attenuation from the compressed fuel/shell. This diagnostic has been fielded on a series of cryogenic shots with DT ion temperatures ranging from 2-5keV. Analysis of the measurement will be presented along with a comparison against simulated electron temperatures and x-ray spectra as well as a comparison to DT ion temperature measurements. This work was performed under the auspices of U.S. DoE by LLNL under Contract No. DE-AC52-07NA27344.

  2. 12th International Workshop on Low Temperature Electronics

    International Nuclear Information System (INIS)

    2017-01-01

    The present volume of the Journal of Physics: Conference Series represents contributions from participants of the 12th International Workshop on Low Temperature Electronics held in Tempe, Arizona, USA from September 18-21, 2016. The conference was organized by the School of Earth and Space Exploration at Arizona State University.The International Workshop on Low Temperature Electronics (WOLTE) is a biennial conference devoted to the presentation and exchange of the most recent advances in the field of low temperature electronics and its applications. This international forum is open to everyone in the field.The technical program included oral presentations and posters on fundamental properties of cryogenic materials, cryogenic transistors, quantum devices and systems, astronomy and physics instrumentation, and fabrication of cryogenic devices. More than 50 scientists and engineers from various academic, government, and industrial institutions in Europe, Asia, and the Americas attended the conference.We would like to thank all speakers for their presentations and all attendees for their participation. We would also like to express our sincerest gratitude to our sponsors: Lake Shore Cryotronics, ASU NewSpace, ASU School of Earth and Space Exploration, and IRA A. Fulton Schools of Engineering for making this conference possible. (paper)

  3. Present-day and future contributions of glacier runoff to summertime flows in a Pacific Northwest watershed: implications for water resources

    Science.gov (United States)

    Anne W. Nolin; Jeff Phillippe; Anne Jefferson; Sarah L. Lewis

    2010-01-01

    While the impacts of long-term climate change trends on glacier hydrology have received much attention, little has been done to quantify direct glacier runoff contributions to streamflow. This paper presents an approach for determining glacier runoff contributions to streamflow and estimating the effects of increased temperature and decreased glacier area on future...

  4. Measurement of electron density and electron temperature of a cascaded arc plasma using laser Thomson scattering compared to an optical emission spectroscopic approach

    Science.gov (United States)

    Yong, WANG; Cong, LI; Jielin, SHI; Xingwei, WU; Hongbin, DING

    2017-11-01

    As advanced linear plasma sources, cascaded arc plasma devices have been used to generate steady plasma with high electron density, high particle flux and low electron temperature. To measure electron density and electron temperature of the plasma device accurately, a laser Thomson scattering (LTS) system, which is generally recognized as the most precise plasma diagnostic method, has been established in our lab in Dalian University of Technology. The electron density has been measured successfully in the region of 4.5 × 1019 m-3 to 7.1 × 1020 m-3 and electron temperature in the region of 0.18 eV to 0.58 eV. For comparison, an optical emission spectroscopy (OES) system was established as well. The results showed that the electron excitation temperature (configuration temperature) measured by OES is significantly higher than the electron temperature (kinetic electron temperature) measured by LTS by up to 40% in the given discharge conditions. The results indicate that the cascaded arc plasma is recombining plasma and it is not in local thermodynamic equilibrium (LTE). This leads to significant error using OES when characterizing the electron temperature in a non-LTE plasma.

  5. Electron temperature effects for an ion beam source

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1979-05-01

    A hydrogen high temperature plasma up to 200 eV is produced by acceleration of electrons in a hot hollow cathode discharge and is used as an ion beam source. Then, two characteristics are observed: A rate of the atomic ion (H + ) number increases above 70%. A perveance of the ion beam increases above 30 times compared with that of a cold plasma, while a floating potential of an ion acceleration electrode approaches an ion acceleration potential (- 500 V) according as an increment of the electron temperature. Moreover, a neutralized ion beam can be produced by only the negative floating electrode without an external power supply. (author)

  6. Insight into runoff characteristics using hydrological modeling in the data-scarce southern Tibetan Plateau: Past, present, and future.

    Directory of Open Access Journals (Sweden)

    Mingyong Cai

    Full Text Available Regional hydrological modeling in ungauged regions has attracted growing attention in water resources research. The southern Tibetan Plateau often suffers from data scarcity in watershed hydrological simulation and water resources assessment. This hinders further research characterizing the water cycle and solving international water resource issues in the area. In this study, a multi-spatial data based Distributed Time-Variant Gain Model (MS-DTVGM is applied to the Yarlung Zangbo River basin, an important international river basin in the southern Tibetan Plateau with limited meteorological data. This model is driven purely by spatial data from multiple sources and is independent of traditional meteorological data. Based on the methods presented in this study, daily snow cover and potential evapotranspiration data in the Yarlung Zangbo River basin in 2050 are obtained. Future (2050 climatic data (precipitation and air temperature from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR5 are used to study the hydrological response to climate change. The result shows that river runoff will increase due to precipitation and air temperature changes by 2050. Few differences are found between daily runoff simulations from different Representative Concentration Pathway (RCP scenarios (RCP2.6, RCP4.5 and RCP8.5 for 2050. Historical station observations (1960-2000 at Nuxia and model simulations for two periods (2006-2009 and 2050 are combined to study inter-annual and intra-annual runoff distribution and variability. The inter-annual runoff variation is stable and the coefficient of variation (CV varies from 0.21 to 0.27. In contrast, the intra-annual runoff varies significantly with runoff in summer and autumn accounting for more than 80% of the total amount. Compared to the historical period (1960-2000, the present period (2006-2009 has a slightly uneven intra-annual runoff temporal distribution, and becomes more

  7. Insight into runoff characteristics using hydrological modeling in the data-scarce southern Tibetan Plateau: Past, present, and future.

    Science.gov (United States)

    Cai, Mingyong; Yang, Shengtian; Zhao, Changsen; Zhou, Qiuwen; Hou, Lipeng

    2017-01-01

    Regional hydrological modeling in ungauged regions has attracted growing attention in water resources research. The southern Tibetan Plateau often suffers from data scarcity in watershed hydrological simulation and water resources assessment. This hinders further research characterizing the water cycle and solving international water resource issues in the area. In this study, a multi-spatial data based Distributed Time-Variant Gain Model (MS-DTVGM) is applied to the Yarlung Zangbo River basin, an important international river basin in the southern Tibetan Plateau with limited meteorological data. This model is driven purely by spatial data from multiple sources and is independent of traditional meteorological data. Based on the methods presented in this study, daily snow cover and potential evapotranspiration data in the Yarlung Zangbo River basin in 2050 are obtained. Future (2050) climatic data (precipitation and air temperature) from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR5) are used to study the hydrological response to climate change. The result shows that river runoff will increase due to precipitation and air temperature changes by 2050. Few differences are found between daily runoff simulations from different Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5 and RCP8.5) for 2050. Historical station observations (1960-2000) at Nuxia and model simulations for two periods (2006-2009 and 2050) are combined to study inter-annual and intra-annual runoff distribution and variability. The inter-annual runoff variation is stable and the coefficient of variation (CV) varies from 0.21 to 0.27. In contrast, the intra-annual runoff varies significantly with runoff in summer and autumn accounting for more than 80% of the total amount. Compared to the historical period (1960-2000), the present period (2006-2009) has a slightly uneven intra-annual runoff temporal distribution, and becomes more balanced in

  8. Hydrology in a mediterranean mountain environment. The Vallcebre research catchment (north eastern Spain) II. Rainfall-runoff relationships and runoff processes

    International Nuclear Information System (INIS)

    Latron, J.; Solar, M.; Nord, G.; Llorens, P.; Gallart, F.

    2009-01-01

    Hydrological response and runoff processes have been studied in the Vallcebre research basins (North Eastern Spain) for almost 20 years. Results obtained allowed to build a more complete perceptual model of the hydrological functioning of Mediterranean mountains basins. On a seasonal and monthly scale, there was no simple relationship between rainfall and runoff depths. Monthly rainfall and runoff values revealed the existence of a threshold in the relationship between rainfall and runoff depths. At the event scale, the storm-flow coefficient had a clear seasonal pattern. The effect of the water table position on how rainfall and runoff volumes relate was observed. Examination of soil water potential and water table dynamics during representative floods helped to identify 3 types of characteristic hydrological behaviour during the year. Under dry conditions, runoff was generated essentially as infiltration excess runoff in low permeable areas, whereas saturation excess runoff dominated during wetting-up and wet conditions. During wetting-up transition, saturated areas resulted from the development of scattered perched water tables, whereas in wet conditions they were linked to the rise of the shallow water table. (Author) 8 refs.

  9. Estimating Runoff Coefficients Using Weather Radars

    DEFF Research Database (Denmark)

    Ahm, Malte; Thorndahl, Søren Liedtke; Rasmussen, Michael R.

    2012-01-01

    This paper presents a method for estimating runoff coefficients of urban drainage catchments based on a combination of high resolution weather radar data and insewer flow measurements. By utilising the spatial variability of the precipitation it is possible to estimate the runoff coefficients...... of separate subcatchments. The method is demonstrated through a case study of an urban drainage catchment (678ha) located in the municipality of Aarhus, Denmark. The study has proven it is possible to use corresponding measurements of the relative rainfall distribution over the catchment and runoff...... measurements to identify the runoff coefficients at subcatchment level. The number of potential subcatchments is limited by the number of available rainfall events with a sufficient spatial variability....

  10. Instability and transport driven by an electron temperature gradient close to critical

    International Nuclear Information System (INIS)

    Dong, J.Q.; Jian, G.D.; Wang, A.K.; Sanuki, H.; Itoh, K.

    2003-01-01

    Electron temperature gradient (ETG) driven instability in toroidal plasmas is studied with gyrokinetic theory. The full electron kinetics is considered. The upgraded numerical scheme for solving the integral eigenvalue equations allows the study of both growing and damping modes, and thus direct calculation of critical gradient. Algebraic formulas for the critical gradient with respect to ratio of electron temperature over ion temperature and to toroidicity are given. An estimation for turbulence induced transport is presented. (author)

  11. Generation of Natural Runoff Monthly Series at Ungauged Sites Using a Regional Regressive Model

    Directory of Open Access Journals (Sweden)

    Dario Pumo

    2016-05-01

    Full Text Available Many hydrologic applications require reliable estimates of runoff in river basins to face the widespread lack of data, both in time and in space. A regional method for the reconstruction of monthly runoff series is here developed and applied to Sicily (Italy. A simple modeling structure is adopted, consisting of a regression-based rainfall–runoff model with four model parameters, calibrated through a two-step procedure. Monthly runoff estimates are based on precipitation, temperature, and exploiting the autocorrelation with runoff at the previous month. Model parameters are assessed by specific regional equations as a function of easily measurable physical and climate basin descriptors. The first calibration step is aimed at the identification of a set of parameters optimizing model performances at the level of single basin. Such “optimal” sets are used at the second step, part of a regional regression analysis, to establish the regional equations for model parameters assessment as a function of basin attributes. All the gauged watersheds across the region have been analyzed, selecting 53 basins for model calibration and using the other six basins exclusively for validation. Performances, quantitatively evaluated by different statistical indexes, demonstrate relevant model ability in reproducing the observed hydrological time-series at both the monthly and coarser time resolutions. The methodology, which is easily transferable to other arid and semi-arid areas, provides a reliable tool for filling/reconstructing runoff time series at any gauged or ungauged basin of a region.

  12. Temperature impact on the primary radiolysis yields concerning the hydrous electron

    International Nuclear Information System (INIS)

    Baldacchino, G.; Vigneron, G.; Pommeret, St.

    2005-01-01

    We have studied the impact of temperature on the water radiolysis formation rate of the hydrous electron in presence of selenate di-anion SeO 4 2+ . We have used a high temperature (up to 500 Celsius degrees) optical cell coupled to the electron accelerator Alienor. It appears that the capture of the hydrous electron by selenate follows an Arrhenius law till the sub-critical range, beyond this range the kinetics of the reaction seems more erratic. We have also studied the capture of the hydrous electron by methyl-viologen (MV 2+ ) at 20 and 380 Celsius degrees. It seems that at high temperature more hydrous electrons are produced, it might be interpreted as a consequence of the shift toward the right of the following equilibrium reaction: OH - + H . ↔ e - (aq) + H 2 O. All these results need to be confirmed. (A.C.)

  13. Parameter estimation in stochastic rainfall-runoff models

    DEFF Research Database (Denmark)

    Jonsdottir, Harpa; Madsen, Henrik; Palsson, Olafur Petur

    2006-01-01

    A parameter estimation method for stochastic rainfall-runoff models is presented. The model considered in the paper is a conceptual stochastic model, formulated in continuous-discrete state space form. The model is small and a fully automatic optimization is, therefore, possible for estimating all...... the parameter values are optimal for simulation or prediction. The data originates from Iceland and the model is designed for Icelandic conditions, including a snow routine for mountainous areas. The model demands only two input data series, precipitation and temperature and one output data series...

  14. Speciation distribution and mass balance of copper and zinc in urban rain, sediments, and road runoff.

    Science.gov (United States)

    Zuo, Xiaojun; Fu, Dafang; Li, He

    2012-11-01

    Heavy metal pollution in road runoff had caused widespread concern since the last century. However, there are little references on metal speciation in multiple environmental media (e.g., rain, road sediments, and road runoff). Our research targeted the investigation of metal speciation in rain, road sediments, and runoff; the analysis of speciation variation and mass balance of metals among rain, road sediments, and runoff; the selection of main factors by principal component analysis (PCA); and the establishment of equation to evaluate the impact of rain and road sediments to metals in road runoff. Sequential extraction procedure contains five steps for the chemical fractionation of metals. Flame atomic absorption spectrometry (Shimadzu, AA-6800) was used to determine metal speciation concentration, as well as the total and dissolved fractions. The dissolved fractions for both Cu and Zn were dominant in rain. The speciation distribution of Zn was different from that of Cu in road sediments, while speciation distribution of Zn is similar to that of Cu in runoff. The bound to carbonates for both Cu and Zn in road sediments were prone to be dissolved by rain. The levels of Cu and Zn in runoff were not obviously influenced by rain, but significantly influenced by road sediments. The masses for both Cu and Zn among rain, road sediments, and road runoff approximately meet the mass balance equation for all rainfall patterns. Five principal factors were selected for metal regression equation based on PCA, including rainfall, average rainfall intensity, antecedent dry periods, total suspended particles, and temperature. The established regression equations could be used to predict the effect of road runoff on receiving environments.

  15. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  16. Saturation mechanism of decaying ion temperature gradient driven turbulence with kinetic electrons

    International Nuclear Information System (INIS)

    Idomura, Yasuhiro

    2016-01-01

    We present full-f gyrokinetic simulations of the ion temperature gradient driven (ITG) turbulence including kinetic electrons. By comparing decaying ITG turbulence simulations with adiabatic and kinetic electron models, an impact of kinetic electrons on the ITG turbulence is investigated. It is found that significant electron transport occurs even in the ITG turbulence, and both ion and electron temperature profiles are relaxed. In steady states, both cases show upshifts of nonlinear critical ion temperature gradients from linear ones, while their saturation mechanisms are qualitatively different. In the adiabatic electron case, the ITG mode is stabilized by turbulence driven zonal flows. On the other hand, in the kinetic electron case, passing electrons transport shows fine resonant structures at mode rational surfaces, which generate corrugated density profiles. Such corrugated density profiles lead to fine radial electric fields following the neoclassical force balance relation. The resulting E × B shearing rate greatly exceeds the linear growth rate of the ITG mode. (author)

  17. Influence of Cattle Trails on Runoff Quantity and Quality.

    Science.gov (United States)

    Miller, Jim J; Curtis, Tony; Chanasyk, David S; Willms, Walter D

    2017-03-01

    Cattle trails in grazed pastures close to rivers may adversely affect surface water quality of the adjacent river by directing runoff to it. The objective of this 3-yr study (2013-2015) in southern Alberta, Canada, was to determine if cattle trails significantly increased the risk of runoff and contaminants (sediment, nutrients) compared with the adjacent grazed pasture (control). A portable rainfall simulator was used to generate artificial rainfall (140 mm h) and runoff. The runoff properties measured were time to runoff and initial abstraction (infiltration), total runoff depth and average runoff rates, as well as concentrations and mass loads of sediment, N, and P fractions. Cattle trails significantly ( ≤ 0.10) decreased time to runoff and initial abstraction (26-32%) in the 2 yr measured and increased total runoff depth, runoff coefficients, and average runoff rates (21-51%) in 2 of 3 yr. Concentrations of sediment, N, and P fractions in runoff were not significantly greater for cattle trails than for control areas. However, mass loads of total suspended solids (57-85% increase), NH-N (31-90%), and dissolved reactive P (DRP) (30-92%) were significantly greater because of increased runoff volumes. Overall, runoff quantity and loads of sediment, NH-N, and DRP were greater for cattle trails compared with the adjacent grazed pasture, and hydrologic connection with cattle-access sites on the riverbank suggests that this could adversely affect water quality in the adjacent river. Extrapolation of the study results should be tempered by the specific conditions represented by this rainfall simulation study. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. Characterization of electron temperature by simulating a multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Yeong Heum [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Lee, Jong Chul; Mohamed Gad, Khaled Mohamed [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Namgoong, Ho [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Chai, Jong Seo, E-mail: jschai@skku.edu [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of)

    2016-12-01

    Multicusp ion sources are used in cyclotrons and linear accelerators to produce high beam currents. The structure of a multicusp ion source consists of permanent magnets, filaments, and an anode body. The configuration of the array of permanent magnets, discharge voltage of the plasma, extraction bias voltage, and structure of the multicusp ion source body decide the quality of the beam. The electrons are emitted from the filament by thermionic emission. The emission current can be calculated from thermal information pertaining to the filament, and from the applied voltage and current. The electron trajectories were calculated using CST Particle Studio to optimize the plasma. The array configuration of the permanent magnets decides the magnetic field inside the ion source. The extraction bias voltage and the structure of the multicusp ion source body decide the electric field. Optimization of the electromagnetic field was performed with these factors. CST Particle Studio was used to calculate the electron temperature with a varying permanent magnet array. Four types of permanent magnet array were simulated to optimize the electron temperature. It was found that a 2-layer full line cusp field (with inverse field) produced the best electron temperature control behavior.

  19. Excess electron mobility in ethane. Density, temperature, and electric field effects

    International Nuclear Information System (INIS)

    Doeldissen, W.; Schmidt, W.F.; Bakale, G.

    1980-01-01

    The excess electron mobility in liquid ethane was measured under orthobaric conditions as a function of temperature and electric field strength up to the critical temperature at 305.33 K. The low field mobility was found to rise strongly with temperature and exhibits a maximum value of 44 cm 2 V -1 s -1 at 2 0 below the critical temperature. At temperatures above 260 K the electron drift velocity shows a sublinear field dependence at high values of the electric field strength. These observations lead to the supposition that in liquid ethane a transition from transport via localized states to transport in extended states occurs. Measurements were also performed in fluid ethane at densities from 2.4 to 12.45 mol L -1 and temperatures from 290 to 340 K. On isochores in the vicinity of the critical density, an increase of the low field mobility with temperature was observed. This effect was found to disappear both at low (rho = 2.4 mol L -1 ) and high densities (rho greater than or equal to 9.2 mol L -1 ). In this density range, a sublinear field dependence of the drift velocities at high field strengths was noted. The critical velocity associated with the appearance of hot electrons was observed to decrease with higher densities indicating a smaller fractional energy transfer in electron molecule collisions. A compilation of electron mobilities in gaseous and liquid ethane shows that, up to densitiesof rho = 9.5 mol L -1 , μ proportional to n -1 is fulfilled if temperature effects are ignored. At intermediate densities, 9 mol L -1 -1 , a density dependence of μ proportional to rho -5 is found followed by a stronger mobility decrease toward the triple point. Positive ion mobilities measured under orthobaric conditions followed Walden's rule

  20. Anomaly in the Kumakhov radiation temperature dependence at axial channeling of electrons

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, F.F.; Telegin, V.I.; Khokonov, M.Kh.

    1983-01-01

    The results of numerical solution of a kinetic equation for distribution function of axially channelled electrons obtained by Belostritsky and Kumakhov at different temperatures of crystals and calculated for the determined electron distributions spectral density of radiation are given. Analysis of the obtained dependence of the number of channelled 5 GeV electrons in tungsten along the <111> axis on depth Z has revealed that 2% of incidence beam electrons have anomalously large depths of dechannelling. Ratio of electrons with large by modulus cross section energies grows at decreasing crystal temperature from 293 to 40 K and, therefore, radiation intensity increases. Two-fold increase of radiation intensity can be attained at axial channelling of 1 GeV electrons in tungsten <111> at the temperatures of the crystal equal to 40 and 293 K and its thickness equal to 220 ..mu..m.

  1. High temperature electrons exhausted from rf plasma sources along a magnetic nozzle

    Science.gov (United States)

    Takahashi, Kazunori; Akahoshi, Hikaru; Charles, Christine; Boswell, Rod W.; Ando, Akira

    2017-08-01

    Two dimensional profiles of electron temperature are measured inside and downstream of a radiofrequency plasma thruster source having a magnetic nozzle and being immersed in vacuum. The temperature is estimated from the slope of the fully swept I-V characteristics of a Langmuir probe acquired at each spatial position and with the assumption of a Maxwellian distribution. The results show that the peripheral high temperature electrons in the magnetic nozzle originate from the upstream antenna location and are transported along the "connecting" magnetic field lines. Two-dimensional measurements of electron energy probability functions are also carried out in a second simplified laboratory device consisting of the source contiguously connected to the diffusion chamber: again the high temperature electrons are detected along the magnetic field lines intersecting the wall at the antenna location, even when the antenna location is shifted along the main axis. These results demonstrate that the peripheral energetic electrons in the magnetic nozzle mirror those created in the source tube.

  2. Analysis of long-term trends (1950–2009) in precipitation, runoff and runoff coefficient in major urban watersheds in the United States

    International Nuclear Information System (INIS)

    Velpuri, N M; Senay, G B

    2013-01-01

    This study investigates the long-term trends in precipitation, runoff and runoff coefficient in major urban watersheds in the United States. The seasonal Mann–Kendall trend test was performed on monthly precipitation, runoff and runoff coefficient data from 1950 to 2009 obtained from 62 urban watersheds covering 21 major urban centers in the United States. The results indicate that only five out of 21 urban centers in the United States showed an uptrend in precipitation. Twelve urban centers showed an uptrend in runoff coefficient. However, six urban centers did not show any trend in runoff coefficient, and three urban centers showed a significant downtrend. The highest rate of change in precipitation, runoff and runoff coefficient was observed in the Houston urban watershed. Based on the results obtained, we also attributed plausible causes for the trends. Our analysis indicated that while a human only influence is observed in most of the urban watersheds, a combined climate and human influence is observed in the central United States. (letter)

  3. Effect of climate change on runoff of Campylobacter and Cryptosporidium from land to surface water.

    Science.gov (United States)

    Sterk, Ankie; Schijven, Jack; de Roda Husman, Ana Maria; de Nijs, Ton

    2016-05-15

    Faeces originating from wildlife, domestic animals or manure-fertilized fields, is considered an important source of zoonotic pathogens to which people may be exposed by, for instance, bathing or drinking-water consumption. An increase in runoff, and associated wash-off of animal faeces from fields, is assumed to contribute to the increase of disease outbreaks during periods of high precipitation. Climate change is expected to increase winter precipitation and extreme precipitation events during summer, but has simultaneously also other effects such as temperature rise and changes in evapotranspiration. The question is to what extent the combination of these effects influence the input of zoonotic pathogens to the surface waters. To quantitatively analyse the impacts of climate change on pathogen runoff, pathogen concentrations reaching surface waters through runoff were calculated by combining an input model for catchment pathogen loads with the Wageningen Lowland Runoff Simulator (WALRUS). Runoff of Cryptosporidium and Campylobacter was evaluated under different climate change scenarios and by applying different scenarios for sources of faecal pollution in the catchments, namely dairy cows and geese and manure fertilization. Model evaluation of these scenarios shows that climate change has little overall impact on runoff of Campylobacter and Cryptosporidium from land to the surface waters. Even though individual processes like runoff fluxes, pathogen release and dilution are affected, either positively or negatively, the net effect on the pathogen concentration in surface waters and consequently also on infection risks through recreation seems limited. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Future Changes in Surface Runoff over Korea Projected by a Regional Climate Model under A1B Scenario

    Directory of Open Access Journals (Sweden)

    Ji-Woo Lee

    2014-01-01

    Full Text Available This study assesses future change of surface runoff due to climate change over Korea using a regional climate model (RCM, namely, the Global/Regional Integrated Model System (GRIMs, Regional Model Program (RMP. The RMP is forced by future climate scenario, namely, A1B of Intergovernmental Panel on Climate Change (IPCC Fourth Assessment Report (AR4. The RMP satisfactorily reproduces the observed seasonal mean and variation of surface runoff for the current climate simulation. The distribution of monsoonal precipitation-related runoff is adequately captured by the RMP. In the future (2040–2070 simulation, it is shown that the increasing trend of temperature has significant impacts on the intra-annual runoff variation. The variability of runoff is increased in summer; moreover, the strengthened possibility of extreme occurrence is detected in the future climate. This study indicates that future climate projection, including surface runoff and its variability over Korea, can be adequately addressed on the RMP testbed. Furthermore, this study reflects that global warming affects local hydrological cycle by changing major water budget components. This study adduces that the importance of runoff should not be overlooked in regional climate studies, and more elaborate presentation of fresh-water cycle is needed to close hydrological circulation in RCMs.

  5. Extracting information from an ensemble of GCMs to reliably assess future global runoff change

    NARCIS (Netherlands)

    Sperna Weiland, F.C.; Beek, L.P.H. van; Weerts, A.H.; Bierkens, M.F.P.

    2011-01-01

    Future runoff projections derived from different global climate models (GCMs) show large differences. Therefore, within this study the, information from multiple GCMs has been combined to better assess hydrological changes. For projections of precipitation and temperature the Reliability ensemble

  6. Non-monotonic behavior of electron temperature in argon inductively coupled plasma and its analysis via novel electron mean energy equation

    Science.gov (United States)

    Zhao, Shu-Xia

    2018-03-01

    In this work, the behavior of electron temperature against the power in argon inductively coupled plasma is investigated by a fluid model. The model properly reproduces the non-monotonic variation of temperature with power observed in experiments. By means of a novel electron mean energy equation proposed for the first time in this article, this electron temperature behavior is interpreted. In the overall considered power range, the skin effect of radio frequency electric field results in localized deposited power density, responsible for an increase of electron temperature with power by means of one parameter defined as power density divided by electron density. At low powers, the rate fraction of multistep and Penning ionizations of metastables that consume electron energy two times significantly increases with power, which dominates over the skin effect and consequently leads to the decrease of temperature with power. In the middle power regime, a transition region of temperature is given by the competition between the ionizing effect of metastables and the skin effect of electric field. The power location where the temperature alters its trend moves to the low power end as increasing the pressure due to the lack of metastables. The non-monotonic curve of temperature is asymmetric at the short chamber due to the weak role of skin effect in increasing the temperature and tends symmetric when axially prolonging the chamber. Still, the validity of the fluid model in this prediction is estimated and the role of neutral gas heating is guessed. This finding is helpful for people understanding the different trends of temperature with power in the literature.

  7. Water erosion in surface soil conditions: runoff velocity, concentration and D50 index of sediments in runoff

    OpenAIRE

    Ramos,Júlio César; Bertol,Ildegardis; Barbosa,Fabrício Tondello; Bertól,Camilo; Mafra,Álvaro Luiz; Miquelluti,David José; Mecabô Júnior,José

    2016-01-01

    ABSTRACT Water erosion and contamination of water resources are influenced by concentration and diameter of sediments in runoff. This study aimed to quantify runoff velocity and concentration and the D50 index of sediments in runoff under different soil surface managements, in the following treatments: i) cropped systems: no-tilled soil covered by ryegrass (Lolium multiflorum Lam.) residue, with high soil cover and minimal roughness (HCR); no tilled soil covered by vetch (Vicia sativa L.) res...

  8. Testing the Runoff Tool in Sicilian vineyards: adopting best management practices to prevent agricultural surface runoff

    Science.gov (United States)

    Singh, Manpriet; Dyson, Jeremy; Capri, Ettore

    2016-04-01

    Over the last decades rainfall has become more intense in Sicily, making large proportions of steeply sloping agricultural land more vulnerable to soil erosion, mainly orchards and vineyards (Diodato and Bellocchi 2010). The prevention of soil degradation is indirectly addressed in the European Union's Water Framework Directive (2000/60/EC) and Sustainable Use Directive (2009/128/EC). As a consequence, new EU compliance conditions for food producers requires them to have tools and solutions for on-farm implementation of sustainable practices (Singh et al. 2014). The Agricultural Runoff and Best Management Practice Tool has been developed by Syngenta to help farm advisers and managers diagnose the runoff potential from fields with visible signs of soil erosion. The tool consists of 4 steps including the assessment of three key landscape factors (slope, topsoil permeability and depth to restrictive horizon) and 9 mainly soil and crop management factors influencing the runoff potential. Based on the runoff potential score (ranging from 0 to 10), which is linked to a runoff potential class, the Runoff Tool uses in-field and edge-of-the-field Best Management Practices (BMPs) to mitigate runoff (aligned with advice from ECPA's TOPPS-prowadis project). The Runoff tool needs testing in different regions and crops to create a number of use scenarios with regional/crop specific advice on BMPs. For this purpose the Tool has been tested in vineyards of the Tasca d'Almerita and Planeta wineries, which are large family-owned estates with long-standing tradition in viticulture in Sicily. In addition to runoff potential scores, Visual Soil Assessment (VSA) scores have been calculated to allow for a comparison between different diagnostic tools. VSA allows for immediate diagnosis of soil quality (a higher score means a better soil quality) including many indicators of runoff (Shepherd 2008). Runoff potentials were moderate to high in all tested fields. Slopes were classified as

  9. The Electron Temperature of a Partially Ionized Gas in an Electric Field

    Energy Technology Data Exchange (ETDEWEB)

    Robben, F

    1968-03-15

    The electron temperature of a partially ionized gas in an electric field can be determined by the collision rate for momentum transfer and the collision rate for energy transfer. Mean values of these rates are defined such that a simple expression for the electron temperature is obtained, and which depends, among other things, on the ratio of these mean rates. This ratio is calculated in the Lorentz approximation for power law cross sections, and also as a function of the degree of ionization for a helium plasma. It is pointed out that the complete results of refined transport theory can be used in calculating electron mobility and electron temperature in a multicomponent plasma without undue difficulty.

  10. The Electron Temperature of a Partially Ionized Gas in an Electric Field

    International Nuclear Information System (INIS)

    Robben, F.

    1968-03-01

    The electron temperature of a partially ionized gas in an electric field can be determined by the collision rate for momentum transfer and the collision rate for energy transfer. Mean values of these rates are defined such that a simple expression for the electron temperature is obtained, and which depends, among other things, on the ratio of these mean rates. This ratio is calculated in the Lorentz approximation for power law cross sections, and also as a function of the degree of ionization for a helium plasma. It is pointed out that the complete results of refined transport theory can be used in calculating electron mobility and electron temperature in a multicomponent plasma without undue difficulty

  11. Using Three-Body Recombination to Extract Electron Temperatures of Ultracold Plasmas

    International Nuclear Information System (INIS)

    Fletcher, R. S.; Zhang, X. L.; Rolston, S. L.

    2007-01-01

    Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of T e -9/2 . We measure three-body recombination in an ultracold neutral xenon plasma by detecting recombination-created Rydberg atoms using a microwave-ionization technique. With the accepted theory (expected to be applicable for weakly coupled plasmas) and our measured rates, we extract the plasma temperatures, which are in reasonable agreement with previous measurements early in the plasma lifetime. The resulting electron temperatures indicate that the plasma continues to cool to temperatures below 1 K

  12. Criteria governing electron plasma waves in a two-temperature plasma

    International Nuclear Information System (INIS)

    Dell, M.P.; Gledhill, I.M.A.; Hellberg, M.A.

    1987-01-01

    Using a technique based on the saddle-points of the dielectric function, criteria are found which govern the behaviour of electron plasma waves in plasmas with two electron populations having different temperatures. (orig.)

  13. Investigating the Influence of Various Stormwater Runoff Control Facilities on Runoff Control Efficiency in a Small Catchment Area

    Directory of Open Access Journals (Sweden)

    Rei Itsukushima

    2018-02-01

    Full Text Available Urbanization causes an increase in the flood discharge because of the infiltration capacity. Furthermore, extreme precipitation events have been an increasing concern for many regions worldwide. This study aimed to investigate the influence of different outflow control facilities on runoff reduction in a small watershed. We focused on the soil-improvement technology and rainwater tanks as outflow control facilities and conducted a runoff calculation using a rainfall event of a magnitude that is likely to occur once in a hundred years. The calculation showed that the soil-improvement technology reduced runoff during long-term continuous rainfall, whereas in a concentrated short-term rainfall event, a significant difference in the runoff reduction effect between rainfall tanks of various volumes was observed. Since effective countermeasures for runoff reduction differ depending on the rainfall distribution pattern, we suggested both facilities for storing initial rainfall and initiating countermeasures for penetration improvement over the long term.

  14. Sampling and chemical analysis of urban street runoff

    International Nuclear Information System (INIS)

    Daub, J.; Striebel, T.; Robien, A.; Herrmann, R.

    1993-01-01

    In order to characterize the environmentally relevant physical and chemical properties of urban street runoff, an automatic sampling device was developed. Precipitation samples were collected together with runoff samples. Organic and inorganic compounds were analysed in the runoff. Dissolved and particle bound substances were analysed separately. The concentrations in runoff are generally considerably higher than in precipitation. Concentrations of lead, fluoranthene and benzo(a)pyrene, in particular are higher in runoffs at sites with high traffic densities than at sites with low traffic densities. Preceding dry period normally has no effect on the measured concentrations. The typical chemograph of a dissolved substance shows a maximum at the beginning of the event dropping quickly to a minimum, which often coincides with the maximum in runoff rate. A slight rise is observed with decreasing runoff rates at the end of the event. Applying a mathematical model, chemographs may be described by three terms: - Relatively large amounts of easily soluble material at the beginning of the event decrease with increasing runoff. Conservative behaviour is assumed. - A part which varies inversely to the runoff rate. This term assumes zero-order kinetics; the amount dissolved from surfaces is constant with time. - A small constant term. Concentrations of particle bound substances correlate with amounts of total suspended solids. Frequently a negative correlation between the specific concentration of substances and the concentration of total suspended solids is observed. (orig.) [de

  15. Global drivers effect in multi-annual variability of runoff

    Directory of Open Access Journals (Sweden)

    Fendeková Miriam

    2014-09-01

    Full Text Available Changes in runoff parameters are very important for Slovakia, where stream-flow discharges, being supplied by precipitation and groundwater runoff, are preferentially influenced by climatic conditions. Therefore, teleconnections between runoff parameters, climate parameters and global atmospheric drivers such as North Atlantic Oscillation, Southern Pacific Oscillation, Quasi-biennial oscillation and solar activity were studied in the Nitra River Basin, Slovakia. Research was mostly based on records of 80 years (1931-2010 for discharges and baseflow, and 34 years for groundwater heads. Methods of autocorrelation, spectral analysis, cross-correlation and coherence function were used. Results of auto- correllograms for discharges, groundwater heads and base flow values showed a very distinct 11-year and 21-year periodicity. Spectrogram analysis documented the 11-year, 7.8-year, 3.6-year and 2.4-year periods in the discharge, precipitation and air temperature time series. The same cycles except of 11-years were also identified in the long-term series of the North Atlantic Oscillation and Southern Pacific Oscillation indices. The cycle from approximately 2.3 to 2.4-years is most likely connected with Quasi-biennial oscillation. The close negative correlation between the North Atlantic Oscillation winter index and the hydrological surface and groundwater parameters can be used for their prediction within the same year and also for one year in advance.

  16. To the problem of electron temperature control in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Galechyan, G.A. [Institute of Applied Problem of Physics, Yerevan (Armenia); Anna, P.R. [Raritan Valley Community College, Somerville, NJ (United States)

    1995-12-31

    One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO{sub 2} laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall.

  17. To the problem of electron temperature control in plasma

    International Nuclear Information System (INIS)

    Galechyan, G.A.; Anna, P.R.

    1995-01-01

    One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO 2 laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall

  18. Electron energy distribution function, effective electron temperature, and dust charge in the temporal afterglow of a plasma

    International Nuclear Information System (INIS)

    Denysenko, I. B.; Azarenkov, N. A.; Kersten, H.

    2016-01-01

    Analytical expressions describing the variation of electron energy distribution function (EEDF) in an afterglow of a plasma are obtained. Especially, the case when the electron energy loss is mainly due to momentum-transfer electron-neutral collisions is considered. The study is carried out for different EEDFs in the steady state, including Maxwellian and Druyvesteyn distributions. The analytical results are not only obtained for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy but also for the case when the collisions are a power function of electron energy. Using analytical expressions for the EEDF, the effective electron temperature and charge of the dust particles, which are assumed to be present in plasma, are calculated for different afterglow durations. An analytical expression for the rate describing collection of electrons by dust particles for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy is also derived. The EEDF profile and, as a result, the effective electron temperature and dust charge are sufficiently different in the cases when the rate for momentum-transfer electron-neutral collisions is independent on electron energy and when the rate is a power function of electron energy.

  19. Run-off from roofs

    International Nuclear Information System (INIS)

    Roed, J.

    1985-01-01

    In order to find the run-off from roof material a roof has been constructed with two different slopes (30 deg C and 45 deg C). Beryllium-7 and caesium-137 has been used as tracers. Considering new roof material the pollution removed by runoff processes has been shown to be very different for various roof materials. The pollution is much more easily removed from silicon-treated material than from porous red-tile roof material. Caesium is removed more easily than beryllium. The content of caesium in old roof materials is greater in red-tile than in other less-porous materials. However, the measured removal from new material does not correspond to the amount accumulated in the old. This could be explained by weathering and by saturation effects. This last effect is probably the more important. The measurements on old material indicates a removal of 44-86% of the caesium pollution by run-off, whereas the measurement on new showed a removal of only 31-50%. It has been demonstrated that the pollution concentration in the run-off water could be very different from that in rainwater. The work was part of the EEC Radiation Protection Programme and done under a subcontract with Association Euratom-C.E.A. No. SC-014-BIO-F-423-DK(SD) under contract No. BIO-F-423-81-F. (author)

  20. Electronic Monitoring Of Storage And Transport Temperatures Of ...

    African Journals Online (AJOL)

    Electronic Monitoring Of Storage And Transport Temperatures Of Thermostable Newcastle ... 22) were monitored during storage and transport from vaccine production laboratory in Temeke, Dar es ... EMAIL FULL TEXT EMAIL FULL TEXT

  1. Improved Temperature Diagnostic for Non-Neutral Plasmas with Single-Electron Resolution

    Science.gov (United States)

    Shanman, Sabrina; Evans, Lenny; Fajans, Joel; Hunter, Eric; Nelson, Cheyenne; Sierra, Carlos; Wurtele, Jonathan

    2016-10-01

    Plasma temperature diagnostics in a Penning-Malmberg trap are essential for reliably obtaining cold, non-neutral plasmas. We have developed a setup for detecting the initial electrons that escape from a trapped pure electron plasma as the confining electrode potential is slowly reduced. The setup minimizes external noise by using a silicon photomultiplier to capture light emitted from an MCP-amplified phosphor screen. To take advantage of this enhanced resolution, we have developed a new plasma temperature diagnostic analysis procedure which takes discrete electron arrival times as input. We have run extensive simulations comparing this new discrete algorithm to our existing exponential fitting algorithm. These simulations are used to explore the behavior of these two temperature diagnostic procedures at low N and at high electronic noise. This work was supported by the DOE DE-FG02-06ER54904, and the NSF 1500538-PHY.

  2. Electron-beam damaged high-temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Pauza, A.J.; Booij, W.E.; Herrmann, K.; Moore, D.F.; Blamire, M.G.; Rudman, D.A.; Vale, L.R.

    1997-01-01

    Results are presented on the fabrication and characterization of high critical temperature Josephson junctions in thin films of YBa 2 Cu 3 O 7-δ produced by the process of focused electron-beam irradiation using 350 keV electrons. The junctions so produced have uniform spatial current densities, can be described in terms of the resistive shunted junction model, and their current densities can be tailored for a given operating temperature. The physical properties of the damaged barrier can be described as a superconducting material of either reduced or zero critical temperature (T c ), which has a length of ∼15nm. The T c reduction is caused primarily by oxygen Frenkel defects in the Cu - O planes. The large beam currents used in the fabrication of the junctions mean that the extent of the barrier is limited by the incident electron-beam diameter, rather than by scattering within the film. The properties of the barrier can be calculated using a superconductor/normal/superconductor (SNS) junction model with no boundary resistance. From the SNS model, we can predict the scaling of the critical current resistance (I c R n ) product and gain insight into the factors controlling the junction properties, T c , and reproducibility. From the measured I c R n scaling data, we can predict the I c R n product of a junction at a given operating temperature with a given current density. I c R n products of ∼2mV can be achieved at 4.2 K. The reproducibility of several junctions in a number of samples can be characterized by the ratio of the maximum-to-minimum critical currents on the same substrate of less than 1.4. Stability over several months has been demonstrated at room and refrigerator temperatures (297 and 281 K) for junctions that have been initially over damaged and then annealed at temperatures ∼380K. (Abstract Truncated)

  3. Hotspot electron temperature from x-ray continuum measurements on the NIF

    International Nuclear Information System (INIS)

    Jarrott, L. C.; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A.

    2016-01-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  4. Hotspot electron temperature from x-ray continuum measurements on the NIF

    Science.gov (United States)

    Jarrott, L. C.; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A.

    2016-11-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  5. Hotspot electron temperature from x-ray continuum measurements on the NIF.

    Science.gov (United States)

    Jarrott, L C; Benedetti, L R; Chen, H; Izumi, N; Khan, S F; Ma, T; Nagel, S R; Landen, O L; Pak, A; Patel, P K; Schneider, M; Scott, H A

    2016-11-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  6. Hotspot electron temperature from x-ray continuum measurements on the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Jarrott, L. C., E-mail: jarrott1@llnl.gov; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  7. A Theory of Strategic Voting in Runoff Elections

    OpenAIRE

    Laurent Bouton

    2013-01-01

    This paper analyzes the properties of runoff electoral systems when voters are strategic. A model of three-candidate runoff elections is presented, and two new features are included: the risk of upset victory in the second round is endogenous, and many types of runoff systems are considered. Three main results emerge. First, runoff elections produce equilibria in which only two candidates receive a positive fraction of the votes. Second, a sincere voting equilibrium does not always exist. Fin...

  8. Temperature dependence of electronic transport property in ferroelectric polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X.L.; Wang, J.L., E-mail: jlwang@mail.sitp.ac.cn; Tian, B.B.; Liu, B.L.; Zou, Y.H.; Wang, X.D.; Sun, S.; Sun, J.L., E-mail: jlsun@mail.sitp.ac.cn; Meng, X.J.; Chu, J.H.

    2014-10-15

    Highlights: • The ferroelectric polymer was fabricated by Langmuir–Blodgett method. • The electrons as the dominant injected carrier were conformed in the ferroelectric polymer films. • The leakage current conduction mechanisms in ferroelectric polymer were investigated. - Abstract: The leakage current mechanism of ferroelectric copolymer of polyvinylidene fluoride with trifluoroethylene prepared by Langmuir–Blodgett was investigated in the temperature range from 100 K to 350 K. The electron as the dominant injected carrier was observed in the ferroelectric copolymer films. The transport mechanisms in copolymer strongly depend on the temperature and applied voltage. From 100 K to 200 K, Schottky emission dominates the conduction. With temperature increasing, the Frenkel–Poole emission instead of the Schottky emission to conduct the carrier transport. When the temperature gets to 260 K, the leakage current becomes independent of temperature, and the space charge limited current conduction was observed.

  9. Contributions of climate change and human activities to runoff change in seven typical catchments across China.

    Science.gov (United States)

    Zhai, Ran; Tao, Fulu

    2017-12-15

    Climate change and human activities are two major factors affecting water resource change. It is important to understand the roles of the major factors in affecting runoff change in different basins for watershed management. Here, we investigated the trends in climate and runoff in seven typical catchments in seven basins across China from 1961 to 2014. Then we attributed the runoff change to climate change and human activities in each catchment and in three time periods (1980s, 1990s and 2000s), using the VIC model and long-term runoff observation data. During 1961-2014, temperature increased significantly, while the trends in precipitation were insignificant in most of the catchments and inconsistent among the catchments. The runoff in most of the catchments showed a decreasing trend except the Yingluoxia catchment in the northwestern China. The contributions of climate change and human activities to runoff change varied in different catchments and time periods. In the 1980s, climate change contributed more to runoff change than human activities, which was 84%, 59%, -66%, -50%, 59%, 94%, and -59% in the Nianzishan, Yingluoxia, Xiahui, Yangjiaping, Sanjiangkou, Xixian, and Changle catchment, respectively. After that, human activities had played a more essential role in runoff change. In the 1990s and 2000s, human activities contributed more to runoff change than in the 1980s. The contribution by human activities accounted for 84%, -68%, and 67% in the Yingluoxia, Xiahui, and Sanjiangkou catchment, respectively, in the 1990s; and -96%, -67%, -94%, and -142% in the Nianzishan, Yangjiaping, Xixian, and Changle catchment, respectively, in the 2000s. It is also noted that after 2000 human activities caused decrease in runoff in all catchments except the Yingluoxia. Our findings highlight that the effects of human activities, such as increase in water withdrawal, land use/cover change, operation of dams and reservoirs, should be well managed. Copyright © 2017 Elsevier

  10. Effective temperature of an ultracold electron source based on near-threshold photoionization

    NARCIS (Netherlands)

    Engelen, W.J.; Smakman, E.P.; Bakker, D.J.; Luiten, O.J.; Vredenbregt, E.J.D.

    2014-01-01

    We present a detailed description of measurements of the effective temperature of a pulsed electron source, based on near-threshold photoionization of laser-cooled atoms. The temperature is determined by electron beam waist scans, source size measurements with ion beams, and analysis with an

  11. APPLICATION OF GIS IN MODELING ZILBERCHAI BASIN RUNOFF

    Directory of Open Access Journals (Sweden)

    L. Malekani

    2014-10-01

    Full Text Available Runoff is one of most important hydrological variables that are used in many civil works, planning for optimal use of reservoirs, organizing rivers and warning flood. The runoff curve number (CN is a key factor in determining runoff in the SCS (Soil Conservation Service based hydrologic modeling method. The traditional SCS-CN method for calculating the composite curve number consumes a major portion of the hydrologic modeling time. Therefore, geographic information systems (GIS are now being used in combination with the SCS-CN method. This work uses a methodology of determining surface runoff by Geographic Information System model and applying SCS-CN method that needs the necessary parameters such as land use map, hydrologic soil groups, rainfall data, DEM, physiographic characteristic of the basin. The model is built by implementing some well known hydrologic methods in GIS like as ArcHydro, ArcCN-Runoff for modeling of Zilberchai basin runoff. The results show that the high average weighted of curve number indicate that permeability of the basin is low and therefore likelihood of flooding is high. So the fundamental works is essential in order to increase water infiltration in Zilberchai basin and to avoid wasting surface water resources. Also comparing the results of the computed and observed runoff value show that use of GIS tools in addition to accelerate the calculation of the runoff also increase the accuracy of the results. This paper clearly demonstrates that the integration of GIS with the SCS-CN method provides a powerful tool for estimating runoff volumes in large basins.

  12. Application of GIS in Modeling Zilberchai Basin Runoff

    Science.gov (United States)

    Malekani, L.; Khaleghi, S.; Mahmoodi, M.

    2014-10-01

    Runoff is one of most important hydrological variables that are used in many civil works, planning for optimal use of reservoirs, organizing rivers and warning flood. The runoff curve number (CN) is a key factor in determining runoff in the SCS (Soil Conservation Service) based hydrologic modeling method. The traditional SCS-CN method for calculating the composite curve number consumes a major portion of the hydrologic modeling time. Therefore, geographic information systems (GIS) are now being used in combination with the SCS-CN method. This work uses a methodology of determining surface runoff by Geographic Information System model and applying SCS-CN method that needs the necessary parameters such as land use map, hydrologic soil groups, rainfall data, DEM, physiographic characteristic of the basin. The model is built by implementing some well known hydrologic methods in GIS like as ArcHydro, ArcCN-Runoff for modeling of Zilberchai basin runoff. The results show that the high average weighted of curve number indicate that permeability of the basin is low and therefore likelihood of flooding is high. So the fundamental works is essential in order to increase water infiltration in Zilberchai basin and to avoid wasting surface water resources. Also comparing the results of the computed and observed runoff value show that use of GIS tools in addition to accelerate the calculation of the runoff also increase the accuracy of the results. This paper clearly demonstrates that the integration of GIS with the SCS-CN method provides a powerful tool for estimating runoff volumes in large basins.

  13. Spatial-temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Science.gov (United States)

    Zhai, Ran; Tao, Fulu; Xu, Zhihui

    2018-06-01

    The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs) for the baseline (2006-2015), 1.5, and 2.0 °C warming scenarios (2106-2115) were used to drive the validated Variable Infiltration Capacity (VIC) hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR) across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from -0.45 to 6.71 and -3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD) of TEWR ranged from -10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively correlated to precipitation, while increase in maximum

  14. Active silicon x-ray for measuring electron temperature

    International Nuclear Information System (INIS)

    Snider, R.T.

    1994-07-01

    Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

  15. MODELING OF STORM WATER RUNOFF FROM GREEN ROOFS

    Directory of Open Access Journals (Sweden)

    Ewa Burszta-Adamiak

    2014-10-01

    Full Text Available Apart from direct measurements, modelling of runoff from green roofs is valuable source of information about effectiveness of this type of structure from hydrological point of view. Among different type of models, the most frequently used are numerical models. They allow to assess the impact of green roofs on decrease and attenuation of runoff, reduction of peak runoff and value of water retention. This paper presents preliminary results of research on computing the rate of runoff from green roofs using GARDENIA model. The analysis has been carried out for selected rainfall events registered during measuring campaign on pilot-scale green roofs. Obtained results are promising and show good fit between observed and simulated runoff.

  16. Study of electron temperature evolution during sawtoothing and pellet injection using thermal electron cyclotron emission in the Alcator C tokamak

    International Nuclear Information System (INIS)

    Gomez, C.C.

    1986-05-01

    A study of the electron temperature evolution has been performed using thermal electron cyclotron emission. A six channel far infrared polychromator was used to monitor the radiation eminating from six radial locations. The time resolution was <3 μs. Three events were studied, the sawtooth disruption, propagation of the sawtooth generated heatpulse and the electron temperature response to pellet injection. The sawtooth disruption in Alcator takes place in 20 to 50 μs, the energy mixing radius is approx. 8 cm or a/2. It is shown that this is inconsistent with single resonant surface Kadomtsev reconnection. Various forms of scalings for the sawtooth period and amplitude were compared. The electron heatpulse propagation has been used to estimate chi e(the electron thermal diffusivity). The fast temperature relaxation observed during pellet injection has also been studied. Electron temperature profile reconstructions have shown that the profile shape can recover to its pre-injection form in a time scale of 200 μs to 3 ms depending on pellet size

  17. Measurement of peripheral electron temperature by electron cyclotron emission during the H-mode transition in JFT-2M tokamak

    International Nuclear Information System (INIS)

    Hoshino, Katsumichi; Yamamoto, Takumi; Kawashima, Hisato

    1987-01-01

    Time evolution and profile of peripheral electron temperature during the H-mode like transition in a tokamak plasma is measured using the second and third harmonic of electron cyclotron emission (ECE). The so called ''H-mode'' state which has good particle/energy confinement is characterized by sudden decrease in the spectral line intensity of deuterium molecule. Such a sudden decrease in the line intensity of D α with good energy confinement is found not only in divertor discharges, but also in limiter dischargs in JFT-2M tokamak. It is found by the measurement of ECE that the peripheral electron temperature suddenly increases in both of such phases. The relation between H-transition and the peripheral electron temperature or its profile is investigated. (author)

  18. [A review of green roof performance towards management of roof runoff].

    Science.gov (United States)

    Chen, Xiao-ping; Huang, Pei; Zhou, Zhi-xiang; Gao, Chi

    2015-08-01

    Green roof has a significant influence on reducing runoff volume, delaying runoff-yielding time, reducing the peak flow and improving runoff quality. This paper addressed the related research around the world and concluded from several aspects, i.e., the definition of green roof of different types, the mechanism how green roof manages runoff quantity and quality, the ability how green roof controls roof runoff, and the influence factors of green roof toward runoff quantity and quality. Afterwards, there was a need for more future work on research of green roof toward roof runoff, i.e., vegetation selection of green roof, efficient construction model selection of green roof, the regulating characteristics of green roof on roof runoff, the value assessment of green roof on roof runoff, analysis of source-sink function of green roof on the water pollutants of roof runoff and the research on the mitigation measures of roof runoff pollution. This paper provided a guideline to develop green roofs aiming to regulating roof runoff.

  19. Rainfall and runoff regime trends in mountain catchments (Case study area: the upper Hron River basin, Slovakia

    Directory of Open Access Journals (Sweden)

    Blahušiaková Andrea

    2015-09-01

    Full Text Available This paper presents an analysis of trends and causes of changes of selected hydroclimatic variables influencing the runoff regime in the upper Hron River basin (Slovakia. Different methods for identifying trends in data series are evaluated and include: simple mass curve analysis, linear regression, frequency analysis of flood events, use of the Indicators of Hydrological Alteration software, and the Mann-Kendall test. Analyses are performed for data from two periods (1931-2010 and 1961-2010. The changes in runoff are significant, especially in terms of lower QMax and 75 percentile values. This fact is also confirmed by the lower frequency and extremity of flood events. The 1980s are considered a turning point in the development of all hydroclimatic variables. The Mann-Kendall test shows a significant decrease in runoff in the winter period. The main causes of runoff decline are: the considerable increase in air temperature, the decrease in snow cover depth and changes in seasonal distribution of precipitation amounts.

  20. Effects of electron-ion temperature equilibration on inertial confinement fusion implosions.

    Science.gov (United States)

    Xu, Barry; Hu, S X

    2011-07-01

    The electron-ion temperature relaxation essentially affects both the laser absorption in coronal plasmas and the hot-spot formation in inertial confinement fusion (ICF). It has recently been reexamined for plasma conditions closely relevant to ICF implosions using either classical molecular-dynamics simulations or analytical methods. To explore the electron-ion temperature equilibration effects on ICF implosion performance, we have examined two Coulomb logarithm models by implementing them into our hydrocodes, and we have carried out hydrosimulations for ICF implosions. Compared to the Lee-More model that is currently used in our standard hydrocodes, the two models predict substantial differences in laser absorption, coronal temperatures, and neutron yields for ICF implosions at the OMEGA Laser Facility [Boehly et al. Opt. Commun. 133, 495 (1997)]. Such effects on the triple-picket direct-drive design at the National Ignition Facility (NIF) have also been explored. Based on the validity of the two models, we have proposed a combined model of the electron-ion temperature-relaxation rate for the overall ICF plasma conditions. The hydrosimulations using the combined model for OMEGA implosions have shown ∼6% more laser absorption, ∼6%-15% higher coronal temperatures, and ∼10% more neutron yield, when compared to the Lee-More model prediction. It is also noticed that the gain for the NIF direct-drive design can be varied by ∼10% among the different electron-ion temperature-relaxation models.

  1. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    Science.gov (United States)

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

  2. Snowmelt runoff and water yield along elevation and temperature gradients in California's southern Sierra Nevada

    Science.gov (United States)

    Carolyn T. Hunsaker; Thomas W. Whitaker; Roger C. Bales

    2012-01-01

    Differences in hydrologic response across the rain-snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment...

  3. Variations in erosive wear of metallic materials with temperature via the electron work function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaochen; Yu, Bin [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Yan, X.G. [School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China); Li, D.Y., E-mail: dongyang.li@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China)

    2016-04-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  4. Variations in erosive wear of metallic materials with temperature via the electron work function

    International Nuclear Information System (INIS)

    Huang, Xiaochen; Yu, Bin; Yan, X.G.; Li, D.Y.

    2016-01-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  5. Temperature dependences in electron-stimulated desorption of neutral europium

    CERN Document Server

    Ageev, V N; Madey, T E

    2003-01-01

    The electron-stimulated desorption (ESD) yield for neutral europium (Eu) atoms from Eu layers adsorbed on oxygen-covered tungsten surfaces has been measured as a function of electron energy, europium coverage and degree of oxidation of tungsten, with an emphasis on effects of substrate temperature. The measurements have been carried out using a time-of-flight method and surface ionization detector. We expand on an earlier report, and compare ESD of multivalent Eu with ESD of monovalent alkali atoms, studied previously. The Eu atom ESD is a complicated function of Eu coverage, electron energy and substrate temperature. In the coverage range 0.05-0.35 monolayer (ML), overlapping resonant-like Eu atom yield peaks are observed at electron energies E sub e of 36 and 41 eV that might be associated with Eu or W shallow core level excitations. Additional resonant-like peaks are seen at E sub e of 54 and 84 eV that are associated with W 5p and 5s level excitations. The Eu atom yield peaks at 36 and 41 eV are seen only...

  6. Electron temperature measurement by a helium line intensity ratio method in helicon plasmas

    International Nuclear Information System (INIS)

    Boivin, R.F.; Kline, J.L.; Scime, E.E.

    2001-01-01

    Electron temperature measurements in helicon plasmas are difficult. The presence of intense rf fields in the plasma complicates the interpretation of Langmuir probe measurements. Furthermore, the non-negligible ion temperature in the plasma considerably shortens the lifetime of conventional Langmuir probes. A spectroscopic technique based on the relative intensities of neutral helium lines is used to measure the electron temperature in the HELIX (Hot hELicon eXperiment) plasma [P. A. Keiter et al., Phys. Plasmas 4, 2741 (1997)]. This nonintrusive diagnostic is based on the fact that electron impact excitation rate coefficients for helium singlet and triplet states differ as a function of the electron temperature. The different aspects related to the validity of this technique to measure the electron temperature in rf generated plasmas are discussed in this paper. At low plasma density (n e ≤10 11 cm -3 ), this diagnostic is believed to be very reliable since the population of the emitting level can be easily estimated with reasonable accuracy by assuming that all excitation originates from the ground state (steady-state corona model). At higher density, secondary processes (excitation transfer, excitation from metastable, cascading) become more important and a more complex collisional radiative model must be used to predict the electron temperature. In this work, different helium transitions are examined and a suitable transition pair is identified. For an electron temperature of 10 eV, the line ratio is measured as a function of plasma density and compared to values predicted by models. The measured line ratio function is in good agreement with theory and the data suggest that the excitation transfer is the dominant secondary process in high-density plasmas

  7. Experimental observation of electron-temperature-gradient turbulence in a laboratory plasma.

    Science.gov (United States)

    Mattoo, S K; Singh, S K; Awasthi, L M; Singh, R; Kaw, P K

    2012-06-22

    We report the observation of electron-temperature-gradient (ETG) driven turbulence in the laboratory plasma of a large volume plasma device. The removal of unutilized primary ionizing and nonthermal electrons from uniform density plasma and the imposition and control of the gradient in the electron temperature (T[Symbol: see text] T(e)) are all achieved by placing a large (2 m diameter) magnetic electron energy filter in the middle of the device. In the dressed plasma, the observed ETG turbulence in the lower hybrid range of frequencies ν = (1-80 kHz) is characterized by a broadband with a power law. The mean wave number k perpendicular ρ(e) = (0.1-0.2) satisfies the condition k perpendicular ρ(e) ≤ 1, where ρ(e) is the electron Larmor radius.

  8. Event-based model diagnosis of rainfall-runoff model structures

    International Nuclear Information System (INIS)

    Stanzel, P.

    2012-01-01

    The objective of this research is a comparative evaluation of different rainfall-runoff model structures. Comparative model diagnostics facilitate the assessment of strengths and weaknesses of each model. The application of multiple models allows an analysis of simulation uncertainties arising from the selection of model structure, as compared with effects of uncertain parameters and precipitation input. Four different model structures, including conceptual and physically based approaches, are compared. In addition to runoff simulations, results for soil moisture and the runoff components of overland flow, interflow and base flow are analysed. Catchment runoff is simulated satisfactorily by all four model structures and shows only minor differences. Systematic deviations from runoff observations provide insight into model structural deficiencies. While physically based model structures capture some single runoff events better, they do not generally outperform conceptual model structures. Contributions to uncertainty in runoff simulations stemming from the choice of model structure show similar dimensions to those arising from parameter selection and the representation of precipitation input. Variations in precipitation mainly affect the general level and peaks of runoff, while different model structures lead to different simulated runoff dynamics. Large differences between the four analysed models are detected for simulations of soil moisture and, even more pronounced, runoff components. Soil moisture changes are more dynamical in the physically based model structures, which is in better agreement with observations. Streamflow contributions of overland flow are considerably lower in these models than in the more conceptual approaches. Observations of runoff components are rarely made and are not available in this study, but are shown to have high potential for an effective selection of appropriate model structures (author) [de

  9. High Temperature Wireless Communication And Electronics For Harsh Environment Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Beheim, G. M.; Ponchak, G. E.; Chen, L.-Y

    2007-01-01

    In order for future aerospace propulsion systems to meet the increasing requirements for decreased maintenance, improved capability, and increased safety, the inclusion of intelligence into the propulsion system design and operation becomes necessary. These propulsion systems will have to incorporate technology that will monitor propulsion component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This implies the development of sensors, actuators, and electronics, with associated packaging, that will be able to operate under the harsh environments present in an engine. However, given the harsh environments inherent in propulsion systems, the development of engine-compatible electronics and sensors is not straightforward. The ability of a sensor system to operate in a given environment often depends as much on the technologies supporting the sensor element as the element itself. If the supporting technology cannot handle the application, then no matter how good the sensor is itself, the sensor system will fail. An example is high temperature environments where supporting technologies are often not capable of operation in engine conditions. Further, for every sensor going into an engine environment, i.e., for every new piece of hardware that improves the in-situ intelligence of the components, communication wires almost always must follow. The communication wires may be within or between parts, or from the engine to the controller. As more hardware is added, more wires, weight, complexity, and potential for unreliability is also introduced. Thus, wireless communication combined with in-situ processing of data would significantly improve the ability to include sensors into high temperature systems and thus lead toward more intelligent engine systems. NASA Glenn Research Center (GRC) is presently leading the development of electronics, communication systems, and sensors capable of prolonged stable

  10. High-temperature sensitivity and its acclimation for photosynthetic electron reactions of desert succulents

    Energy Technology Data Exchange (ETDEWEB)

    Chetti, M.B.; Nobel, P.S. (Univ. of California, Los Angeles (USA))

    1987-08-01

    Photosynthetic electron reactions of succulent plants from hot deserts are able to tolerate extremely high temperatures and to acclimate to seasonal increase in temperature. In this study, we report the influence of relatively long, in vivo, high-temperature treatments on electron transport reactions for two desert succulents, Agave deserti and Opuntia ficus-indica, species which can tolerate 60{degree}C. Whole chain electron transport averaged 3{degree}C more sensitive to a 1-hour high-temperature treatment than did PSII (Photosystem II) which in turn averaged 3{degree}C more sensitive than did PSI. For plants maintained at day/night air temperatures of 30{degree}C/20{degree}C, treatment at 50{degree}C cause these reactions to be inhibited an average of 39% during the first hour, an additional 31% during the next 4 hours, and 100% by 12 hours. Upon shifting the plants from 30{degree}C/20{degree}C to 45{degree}C/35{degree}C, the high temperatures where activity was inhibited 50% increased 3{degree}C to 8{degree}C for the three electron transport reactions, the half-times for acclimation averaging 5 days for A. deserti and 4 days for O. ficus-indica. For the 45{degree}C/35{degree}C plants treated at 60{degree}C for 1 hour, PSI activity was reduced by 54% for A. deserti and 36% for O. ficus-indica. Acclimation leads to a toleration of very high temperatures without substantial disruption of electron transport for these desert succulents, facilitating their survival in hot deserts. Indeed, the electron transport reactions of these species tolerate longer periods at higher temperatures than any other vascular plants so far reported.

  11. The impact of edge gradients in the pressure, density, ion temperature, and electron temperature on edge-localized modes

    International Nuclear Information System (INIS)

    Kleva, Robert G.; Guzdar, Parvez N.

    2011-01-01

    The magnitude of the energy and particle fluxes in simulations of edge-localized modes (ELMs) is determined by the edge gradients in the pressure, density, ion temperature, and electron temperature. The total edge pressure gradient is the dominant influence on ELMs by far. An increase (decrease) of merely 2% in the pressure gradient results in an increase (decrease) of more than a factor of ten in the size of the ELM bursts. At a fixed pressure gradient, the size of the ELM bursts decreases as the density gradient increases, while the size of the bursts increases as the electron temperature gradient or, especially, the ion temperature gradient increases.

  12. Effects of rf power on electron density and temperature, neutral temperature, and Te fluctuations in an inductively coupled plasma

    International Nuclear Information System (INIS)

    Camparo, James; Fathi, Gilda

    2009-01-01

    Atomic clocks that fly on global-navigation satellites such as global positioning system (GPS) and Galileo employ light from low-temperature, inductively coupled plasmas (ICPs) for atomic signal generation and detection (i.e., alkali/noble-gas rf-discharge lamps). In this application, the performance of the atomic clock and the capabilities of the navigation system depend sensitively on the stability of the ICP's optical emission. In order to better understand the mechanisms that might lead to instability in these rf-discharge lamps, and hence the satellite atomic clocks, we studied the optical emission from a Rb/Xe ICP as a function of the rf power driving the plasma. Surprisingly, we found that the electron density in the plasma was essentially independent of increases in rf power above its nominal value (i.e., 'rf-power gain') and that the electron temperature was only a slowly varying function of rf-power gain. The primary effect of rf power was to increase the temperature of the neutrals in the plasma, which was manifested by an increase in Rb vapor density. Interestingly, we also found evidence for electron temperature fluctuations (i.e., fluctuations in the plasma's high-energy electron content). The variance of these fluctuations scaled inversely with the plasma's mean electron temperature and was consistent with a simple model that assumed that the total electron density in the discharge was independent of rf power. Taken as a whole, our results indicate that the electrons in alkali/noble-gas ICPs are little affected by slight changes in rf power and that the primary effect of such changes is to heat the plasma's neutral species.

  13. Nonlinear response in runoff magnitude to fluctuating rain patterns.

    Science.gov (United States)

    Curtu, R; Fonley, M

    2015-03-01

    The runoff coefficient of a hillslope is a reliable measure for changes in the streamflow response at the river link outlet. A high runoff coefficient is a good indicator of the possibility of flash floods. Although the relationship between runoff coefficient and streamflow has been the subject of much study, the physical mechanisms affecting runoff coefficient including the dependence on precipitation pattern remain open topics for investigation. In this paper, we analyze a rainfall-runoff model at the hillslope scale as that hillslope is forced with different rain patterns: constant rain and fluctuating rain with different frequencies and amplitudes. When an oscillatory precipitation pattern is applied, although the same amount of water may enter the system, its response (measured by the runoff coefficient) will be maximum for a certain frequency of precipitation. The significant increase in runoff coefficient after a certain pattern of rainfall can be a potential explanation for the conditions preceding flash-floods.

  14. Atomic origin of high-temperature electron trapping in metal-oxide-semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Xiao, E-mail: xiao.shen@vanderbilt.edu [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Dhar, Sarit [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States); Pantelides, Sokrates T. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-04-06

    MOSFETs based on wide-band-gap semiconductors are suitable for operation at high temperature, at which additional atomic-scale processes that are benign at lower temperatures can get activated, resulting in device degradation. Recently, significant enhancement of electron trapping was observed under positive bias in SiC MOSFETs at temperatures higher than 150 °C. Here, we report first-principles calculations showing that the enhanced electron trapping is associated with thermally activated capturing of a second electron by an oxygen vacancy in SiO{sub 2} by which the vacancy transforms into a structure that comprises one Si dangling bond and a bond between a five-fold and a four-fold Si atoms. The results suggest a key role of oxygen vacancies and their structural reconfigurations in the reliability of high-temperature MOS devices.

  15. Rain, Snow, and Spring Runoff Revisited.

    Science.gov (United States)

    Bohren, Craig F.

    1995-01-01

    Explores the theory behind the correlation between warm rain, rapid snowmelt, and the subsequent runoff using the concepts of enthalpy, thermal transfer, and energy transfer. Concludes that rapid runoff is not a consequence of rain per se but of the high humidities associated with the rain. (JRH)

  16. New Temperature-Insensitive Electronically-Tunable Grounded Capacitor Simulator

    OpenAIRE

    Abuelma'atti, Muhammad Taher; Khan, Muhammad Haroon

    1996-01-01

    A new circuit for simulating a grounded capacitor is presented. The circuit uses one operationalamplifier (OA), three operational-transconductance amplifiers (OTAs), and one capacitor. The realized capacitor is temperature-insensitive and electronically tunable. Experimental results are included.

  17. Determination of characteristics maximal runoff mountain rivers in ...

    African Journals Online (AJOL)

    ... water) on the rivers of the Crimean Mountains were used materials of observations for long-term period (from the beginning of observations to 2010 inclusive) on 54 of streamflow station with using a the so-called «operator» model for maximum runoff formation. Keywords: maximum runoff; rain floods; hillslope runoff; karst ...

  18. Prediction and optimization of runoff via ANFIS and GA

    Directory of Open Access Journals (Sweden)

    D.K. Ghose

    2013-06-01

    Full Text Available In planning of water resource projects, the estimation of the availability of water plays an important role. The first step in the water availability estimation is the computation of runoff resulting from the precipitation on river catchments. The length of the runoff measured in a stream may be of short period or long period depending upon the catchment characteristics. Keeping this in mind the present work is focused on two different model generation. In the first phase of this study, runoff rating curves are developed considering present day water level (H(t as input and present day runoff (Q(t as the model output. In the second phase of the study runoff prediction models are developed considering 1 day lag water level (H(t − 1, 2 day lag water level (H(t − 2 and 1 day lag runoff (Q(t − 1 as inputs and 1 day ahead runoff (Q(t + 1 as the output of the model. Models developed and used for prediction of runoff are Non-Linear Multiple Regression (NLMR and Adaptive Neuro-Fuzzy Inference System (ANFIS. Both the models were trained and tested to predict the performance of models. Genetic Algorithm (GA is then coupled with NLMR model to obtain the condition of hydrological parameter for which the runoff is maximum.

  19. Propagation of soil moisture memory to runoff and evapotranspiration

    Science.gov (United States)

    Orth, R.; Seneviratne, S. I.

    2012-10-01

    As a key variable of the land-climate system soil moisture is a main driver of runoff and evapotranspiration under certain conditions. Soil moisture furthermore exhibits outstanding memory (persistence) characteristics. Also for runoff many studies report distinct low frequency variations that represent a memory. Using data from over 100 near-natural catchments located across Europe we investigate in this study the connection between soil moisture memory and the respective memory of runoff and evapotranspiration on different time scales. For this purpose we use a simple water balance model in which dependencies of runoff (normalized by precipitation) and evapotranspiration (normalized by radiation) on soil moisture are fitted using runoff observations. The model therefore allows to compute memory of soil moisture, runoff and evapotranspiration on catchment scale. We find considerable memory in soil moisture and runoff in many parts of the continent, and evapotranspiration also displays some memory on a monthly time scale in some catchments. We show that the memory of runoff and evapotranspiration jointly depend on soil moisture memory and on the strength of the coupling of runoff and evapotranspiration to soil moisture. Furthermore we find that the coupling strengths of runoff and evapotranspiration to soil moisture depend on the shape of the fitted dependencies and on the variance of the meteorological forcing. To better interpret the magnitude of the respective memories across Europe we finally provide a new perspective on hydrological memory by relating it to the mean duration required to recover from anomalies exceeding a certain threshold.

  20. Spatial–temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Directory of Open Access Journals (Sweden)

    R. Zhai

    2018-06-01

    Full Text Available The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs for the baseline (2006–2015, 1.5, and 2.0 °C warming scenarios (2106–2115 were used to drive the validated Variable Infiltration Capacity (VIC hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from −0.45 to 6.71 and −3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD of TEWR ranged from −10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively

  1. Electron temperature in the E-region of the ionosphere

    International Nuclear Information System (INIS)

    Zalpuri, K.S.; Oyama, K.-I.

    1991-06-01

    Various heating and cooling mechanisms which are operative in the lower E-region are discussed and their relative importance in different altitude range is shown. These heating and cooling rates are then used to derive the electron temperature T e . The calculated values of electron temperature are found to be higher than neutral temperature through out the altitude range 100 ∼ 150 km, with the difference increasing with increase in altitude. However, compared to observed values of T e , the calculated values are still smaller below about 130 km. Above this altitude, the calculated values become larger. Estimation of T e for different, suggested values of heating efficiency due to dissociative recombination, show that T e profile obtained even be assuming a constant value of 1.3 eV is in fairly good agreement with those derived based on variable values of this parameter. (author)

  2. Collisional drift waves in a plasma with electron temperature inhomogeneity

    International Nuclear Information System (INIS)

    Drake, J.F.; Hassam, A.B.

    1981-01-01

    A fluid theory of collisional electrostatic drift waves in a plasma slab with magnetic shear is presented. Both electron temperature and density gradients are included. The equations are solved analytically in all relevant regions of the parameter space defined by the magnetic shear strength and the perpendicular wavelength and explicit expressions for the growth rates are given. For shear strengths appropriate for present-day tokamak discharges the temperature gradient produces potential wells which localize the mode in the electron resistive region, well inside the ion sound turning points. Mode stability arises from a competition between the destabilizing influence of the time dependent thermal force and the stabilizing influence of electron energy dissipation. Convective energy loss is not important for shear parameters of present-day fusion devices

  3. Temperature--pressure compensation for a linear accelerator electron beam dosimeter

    International Nuclear Information System (INIS)

    Hrejsa, A.F.; Soen, J.; Jankowiak, P.

    1985-01-01

    Routine weekly calibration of a Siemens Mevatron 20 linear accelerator with 3-, 5-, 7-, 10-, 12-, 15-, and 18-MeV electron energies demonstrated fluctuations in dose/monitor unit for the electron beam on the order of 3%--6%. Evaluations and study of the problem demonstrated that the electron chamber, which is open to atmosphere, was undergoing significant temperature changes during the course of a treatment day. The inability of the chamber to compensate for these changes in temperature and pressure led to the addition of a compensating circuit by the manufacturer. The results of the addition of this circuit were evaluated for several extended periods throughout the year, and it was found that the changes in dose/monitor were reduced to approximately +- 0.5%

  4. The relationship between ionospheric temperature, electron density and solar activity

    International Nuclear Information System (INIS)

    McDonald, J.N.; Williams, P.J.S.

    1980-01-01

    In studying the F-region of the ionosphere several authors have concluded that the difference between the electron temperature Tsub(e) and the ion temperature Tsub(i) is related to the electron density N. It was later noted that solar activity (S) was involved and an empirical relationship of the following form was established: Tsub(e)-Tsub(i) = A-BN+CS. The present paper extends this work using day-time data over a four year period. The results are given and discussed. A modified form of the empirical relation is proposed. (U.K.)

  5. High-Temperature Air-Cooled Power Electronics Thermal Design: Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Waye, Scot [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    Power electronics that use high-temperature devices pose a challenge for thermal management. With the devices running at higher temperatures and having a smaller footprint, the heat fluxes increase from previous power electronic designs. This project overview presents an approach to examine and design thermal management strategies through cooling technologies to keep devices within temperature limits, dissipate the heat generated by the devices and protect electrical interconnects and other components for inverter, converter, and charger applications. This analysis, validation, and demonstration intends to take a multi-scale approach over the device, module, and system levels to reduce size, weight, and cost.

  6. Electronic Structure of the Bismuth Family of High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Lisa

    2002-03-07

    High temperature superconductivity remains the central intellectual problem in condensed matter physics fifteen years after its discovery. Angle resolved photoemission spectroscopy (ARPES) directly probes the electronic structure, and has played an important role in the field of high temperature superconductors. With the recent advances in sample growth and the photoemission technique, we are able to study the electronic structure in great detail, and address regimes that were previously inaccessible. This thesis work contains systematic photoemission studies of the electronic structure of the Bi-family of high temperature superconductors, which include the single-layer system (Bi2201), the bi-layer system (Bi2212), and the tri-layer system (Bi2223). We show that, unlike conventional BCS superconductors, phase coherence information emerges in the single particle excitation spectrum of high temperature superconductors as the superconducting peak in Bi2212. The universality and various properties of this superconducting peak are studied in various systems. We argue that the origin of the superconducting peak may provide the key to understanding the mechanism of High-Tc superconductors. In addition, we identified a new experimental energy scale in the bilayer material, the anisotropic intra-bilayer coupling energy. For a long time, it was predicted that this energy scale would cause bilayer band splitting. We observe this phenomenon, for the first time, in heavily overdoped Bi2212. This new observation requires the revision of the previous picture of the electronic excitation in the Brillouin zone boundary. As the first ARPES study of a trilayer system, various detailed electronic proper- ties of Bi2223 are examined. We show that, comparing with Bi2212, both superconducting gap and relative superconducting peak intensity become larger in Bi2223, however, the strength of the interlayer coupling within each unit cell is possibly weaker. These results suggest that the

  7. Topological Phase Transitions in Zinc-Blende Semimetals Driven Exclusively by Electronic Temperature

    Science.gov (United States)

    Trushin, Egor; Görling, Andreas

    2018-04-01

    We show that electronic phase transitions in zinc-blende semimetals with quadratic band touching (QBT) at the center of the Brillouin zone, like GaBi, InBi, or HgTe, can occur exclusively due to a change of the electronic temperature without the need to involve structural transformations or electron-phonon coupling. The commonly used Kohn-Sham density-functional methods based on local and semilocal density functionals employing the local density approximation (LDA) or generalized gradient approximations (GGAs), however, are not capable of describing such phenomena because they lack an intrinsic temperature dependence and account for temperature only via the occupation of bands, which essentially leads only to a shift of the Fermi level without changing the shape or topology of bands. Kohn-Sham methods using the exact temperature-dependent exchange potential, not to be confused with the Hartree-Fock exchange potential, on the other hand, describe such phase transitions. A simple modeling of correlation effects can be achieved by screening of the exchange. In the considered zinc-blende compounds the QBT is unstable at low temperatures and a transition to electronic states without QBT takes place. In the case of HgTe and GaBi Weyl points of type I and type II, respectively, emerge during the transitions. This demonstrates that Kohn-Sham methods can describe such topological phase transitions provided they are based on functionals more accurate than those within the LDA or GGA. Moreover, the electronic temperature is identified as a handle to tune topological materials.

  8. 2-D Imaging of Electron Temperature in Tokamak Plasmas

    International Nuclear Information System (INIS)

    Munsat, T.; Mazzucato, E.; Park, H.; Domier, C.W.; Johnson, M.; Luhmann, N.C. Jr.; Wang, J.; Xia, Z.; Classen, I.G.J.; Donne, A.J.H.; Pol, M.J. van de

    2004-01-01

    By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented

  9. Ferromagnetism and temperature-dependent electronic structure in metallic films

    International Nuclear Information System (INIS)

    Herrmann, T.

    1999-01-01

    In this work the influence of the reduced translational symmetry on the magnetic properties of thin itinerant-electron films and surfaces is investigated within the strongly correlated Hubbard model. Firstly, the possibility of spontaneous ferromagnetism in the Hubbard model is discussed for the case of systems with full translational symmetry. Different approximation schemes for the solution of the many-body problem of the Hubbard model are introduced and discussed in detail. It is found that it is vital for a reasonable description of spontaneous ferromagnetism to be consistent with exact results concerning the general shape of the single-electron spectral density in the limit of strong Coulomb interaction between the electrons. The temperature dependence of the ferromagnetic solutions is discussed in detail by use of the magnetization curves as well as the spin-dependent quasi particle spectrum. For the investigation of thin films and surfaces the approximation schemes for the bulk system have to be generalized to deal with the reduced translational symmetry. The magnetic behavior of thin Hubbard films is investigated by use of the layer dependent magnetization as a function of temperature as well as the thickness of the film. The Curie-temperature is calculated as a function of the film thickness. Further, the magnetic stability at the surface is discussed in detail. Here it is found that for strong Coulomb interaction the magnetic stability at finite temperatures is reduced at the surface compared to the inner layers. This observation clearly contradicts the well-known Stoner picture of band magnetism and can be explained in terms of general arguments which are based on exact results in the limit of strong Coulomb interaction. The magnetic behavior of the Hubbard films can be analyzed in detail by inspecting the local quasi particle density of states as well as the wave vector dependent spectral density. The electronic structure is found to be strongly spin

  10. Influence of glacier runoff on ecosystem structure in Gulf of Alaska fjords

    Science.gov (United States)

    Arimitsu, Mayumi L.; Piatt, John F.; Mueter, Franz J.

    2016-01-01

    To better understand the influence of glacier runoff on fjord ecosystems, we sampled oceanographic conditions, nutrients, zooplankton, forage fish and seabirds within 4 fjords in coastal areas of the Gulf Alaska. We used generalized additive models and geostatistics to identify the range of glacier runoff influence into coastal waters within fjords of varying estuarine influence and topographic complexity. We also modeled the response of depth-integrated chlorophyll a concentration, copepod biomass, fish and seabird abundance to physical, nutrient and biotic predictor variables. The effects of glacial runoff were traced at least 10 km into coastal fjords by cold, turbid, stratified and generally nutrient-rich near-surface conditions. Glacially modified physical gradients, nutrient availability and among-fjord differences explained 67% of the variation in phytoplankton abundance, which is a driver of ecosystem structure at higher trophic levels. Copepod, euphausiid, fish and seabird distribution and abundance were related to environmental gradients that could be traced to glacial freshwater input, particularly turbidity and temperature. Seabird density was predicted by prey availability and silicate concentrations, which may be a proxy for upwelling areas where this nutrient is in excess. Similarities in ecosystem structure among fjords were attributable to an influx of cold, fresh and sediment-laden water, whereas differences were likely related to fjord topography and local differences in estuarine vs. ocean influence. We anticipate that continued changes in the timing and volume of glacial runoff will ultimately alter coastal ecosystems in the future.

  11. Effective temperature of an ultracold electron source based on near-threshold photoionization.

    Science.gov (United States)

    Engelen, W J; Smakman, E P; Bakker, D J; Luiten, O J; Vredenbregt, E J D

    2014-01-01

    We present a detailed description of measurements of the effective temperature of a pulsed electron source, based on near-threshold photoionization of laser-cooled atoms. The temperature is determined by electron beam waist scans, source size measurements with ion beams, and analysis with an accurate beam line model. Experimental data is presented for the source temperature as a function of the wavelength of the photoionization laser, for both nanosecond and femtosecond ionization pulses. For the nanosecond laser, temperatures as low as 14 ± 3 K were found; for femtosecond photoionization, 30 ± 5 K is possible. With a typical source size of 25 μm, this results in electron bunches with a relative transverse coherence length in the 10⁻⁴ range and an emittance of a few nm rad. © 2013 Elsevier B.V. All rights reserved.

  12. Statistical analysis and modelling of surface runoff from arable fields

    OpenAIRE

    P. Fiener; K. Auerswald; F. Winter; M. Disse

    2013-01-01

    Surface runoff generation on arable fields is an important driver of (local) flooding, on-site and off-site damages by erosion, and of nutrient and agrochemical transport. In general, three different processes generate surface runoff (Hortonian runoff, saturation excess runoff, and return of subsurface flow). Despite the developments in our understanding of these processes it remains difficult to predict, which processes govern runoff generation during the course of an event or through...

  13. Predicting Surface Runoff from Catchment to Large Region

    Directory of Open Access Journals (Sweden)

    Hongxia Li

    2015-01-01

    Full Text Available Predicting surface runoff from catchment to large region is a fundamental and challenging task in hydrology. This paper presents a comprehensive review for various studies conducted for improving runoff predictions from catchment to large region in the last several decades. This review summarizes the well-established methods and discusses some promising approaches from the following four research fields: (1 modeling catchment, regional and global runoff using lumped conceptual rainfall-runoff models, distributed hydrological models, and land surface models, (2 parameterizing hydrological models in ungauged catchments, (3 improving hydrological model structure, and (4 using new remote sensing precipitation data.

  14. Beyond the SCS curve number: A new stochastic spatial runoff approach

    Science.gov (United States)

    Bartlett, M. S., Jr.; Parolari, A.; McDonnell, J.; Porporato, A. M.

    2015-12-01

    The Soil Conservation Service curve number (SCS-CN) method is the standard approach in practice for predicting a storm event runoff response. It is popular because its low parametric complexity and ease of use. However, the SCS-CN method does not describe the spatial variability of runoff and is restricted to certain geographic regions and land use types. Here we present a general theory for extending the SCS-CN method. Our new theory accommodates different event based models derived from alternative rainfall-runoff mechanisms or distributions of watershed variables, which are the basis of different semi-distributed models such as VIC, PDM, and TOPMODEL. We introduce a parsimonious but flexible description where runoff is initiated by a pure threshold, i.e., saturation excess, that is complemented by fill and spill runoff behavior from areas of partial saturation. To facilitate event based runoff prediction, we derive simple equations for the fraction of the runoff source areas, the probability density function (PDF) describing runoff variability, and the corresponding average runoff value (a runoff curve analogous to the SCS-CN). The benefit of the theory is that it unites the SCS-CN method, VIC, PDM, and TOPMODEL as the same model type but with different assumptions for the spatial distribution of variables and the runoff mechanism. The new multiple runoff mechanism description for the SCS-CN enables runoff prediction in geographic regions and site runoff types previously misrepresented by the traditional SCS-CN method. In addition, we show that the VIC, PDM, and TOPMODEL runoff curves may be more suitable than the SCS-CN for different conditions. Lastly, we explore predictions of sediment and nutrient transport by applying the PDF describing runoff variability within our new framework.

  15. Approximating uncertainty of annual runoff and reservoir yield using stochastic replicates of global climate model data

    Science.gov (United States)

    Peel, M. C.; Srikanthan, R.; McMahon, T. A.; Karoly, D. J.

    2015-04-01

    Two key sources of uncertainty in projections of future runoff for climate change impact assessments are uncertainty between global climate models (GCMs) and within a GCM. Within-GCM uncertainty is the variability in GCM output that occurs when running a scenario multiple times but each run has slightly different, but equally plausible, initial conditions. The limited number of runs available for each GCM and scenario combination within the Coupled Model Intercomparison Project phase 3 (CMIP3) and phase 5 (CMIP5) data sets, limits the assessment of within-GCM uncertainty. In this second of two companion papers, the primary aim is to present a proof-of-concept approximation of within-GCM uncertainty for monthly precipitation and temperature projections and to assess the impact of within-GCM uncertainty on modelled runoff for climate change impact assessments. A secondary aim is to assess the impact of between-GCM uncertainty on modelled runoff. Here we approximate within-GCM uncertainty by developing non-stationary stochastic replicates of GCM monthly precipitation and temperature data. These replicates are input to an off-line hydrologic model to assess the impact of within-GCM uncertainty on projected annual runoff and reservoir yield. We adopt stochastic replicates of available GCM runs to approximate within-GCM uncertainty because large ensembles, hundreds of runs, for a given GCM and scenario are unavailable, other than the Climateprediction.net data set for the Hadley Centre GCM. To date within-GCM uncertainty has received little attention in the hydrologic climate change impact literature and this analysis provides an approximation of the uncertainty in projected runoff, and reservoir yield, due to within- and between-GCM uncertainty of precipitation and temperature projections. In the companion paper, McMahon et al. (2015) sought to reduce between-GCM uncertainty by removing poorly performing GCMs, resulting in a selection of five better performing GCMs from

  16. Detection and attribution of nitrogen runoff trend in China's croplands.

    Science.gov (United States)

    Hou, Xikang; Zhan, Xiaoying; Zhou, Feng; Yan, Xiaoyuan; Gu, Baojing; Reis, Stefan; Wu, Yali; Liu, Hongbin; Piao, Shilong; Tang, Yanhong

    2018-03-01

    Reliable detection and attribution of changes in nitrogen (N) runoff from croplands are essential for designing efficient, sustainable N management strategies for future. Despite the recognition that excess N runoff poses a risk of aquatic eutrophication, large-scale, spatially detailed N runoff trends and their drivers remain poorly understood in China. Based on data comprising 535 site-years from 100 sites across China's croplands, we developed a data-driven upscaling model and a new simplified attribution approach to detect and attribute N runoff trends during the period of 1990-2012. Our results show that N runoff has increased by 46% for rice paddy fields and 31% for upland areas since 1990. However, we acknowledge that the upscaling model is subject to large uncertainties (20% and 40% as coefficient of variation of N runoff, respectively). At national scale, increased fertilizer application was identified as the most likely driver of the N runoff trend, while decreased irrigation levels offset to some extent the impact of fertilization increases. In southern China, the increasing trend of upland N runoff can be attributed to the growth in N runoff rates. Our results suggested that increased SOM led to the N runoff rate growth for uplands, but led to a decline for rice paddy fields. In combination, these results imply that improving management approaches for both N fertilizer use and irrigation is urgently required for mitigating agricultural N runoff in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. The Firstflush of Pollutants in Surface Runoff

    OpenAIRE

    Pejman Razi; Amir Taebi

    2005-01-01

    One of the factors impacting quality of water resources is pollution due to urban storm runoff during first stage of storm runoff and is commonly called "firsflush". At this stage the pollution load is rather high. However, if this pollution is properly controlled and managed, the size of the required treatment facilities will be considerably reduced. The surface runoff pollution in the city of Isfahan is high and necessitates the implementation of some control system. For this purpose, ten r...

  18. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures

    International Nuclear Information System (INIS)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2015-01-01

    We extend the definition of the electronic chemical potential (μ e ) and chemical hardness (η e ) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μ e . Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (−I), positive (−A), and zero values of the fractional charge (−(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness

  19. Multi-linear model of transformation of runoff in river-basins

    International Nuclear Information System (INIS)

    Szolgay, J.; Kubes, R.

    2005-01-01

    The component part of atmospheric precipitations-runoff model of Hron River is a individual model of transformation of flows in river network, too, which transforms runoff from separate partial catchment basin into terminal profile. This component of precipitations-runoff model can also be used as individual hydrologic transformation model of runoff waves in river-basin. Identification and calibration of this model is realised independently on precipitations-runoff model of Hron River, which is described in this chapter in detail.

  20. How much complexity is warranted in a rainfall-runoff model? Findings obtained from symbolic regression, using Eureqa

    Science.gov (United States)

    Abrahart, R. J.; Beriro, D. J.

    2012-04-01

    The information content in a rainfall-runoff record is sufficient to support models of only very limited complexity (Jakeman and Hornberger, 1993). This begs the question of what limits should observed data place on the allowable complexity of rainfall-runoff models? Eureqa1 (Schmidt and Lipson, 2009) - pronounced "eureka" - is a software tool for finding equations and detecting mathematical relationships in a dataset. The challenge, for both software and modeller, is to identify, by means of symbolic regression, the simplest mathematical formulas which describe the underlying mechanisms that produced the data. It actually delivers, however, a series of preferred modelling solutions comprising one champion for each specific level of complexity i.e. related to solution enlargement involving the progressive incorporation of additional permitted factors (internal operators/ external drivers). The potential benefit of increased complexity can as a result be assessed in a rational manner. Eureqa is free to download and use; and, in the current study, has been employed to construct a set of rainfall-runoff transfer function models for the Annapolis River at Wilmot, in north-western Nova Scotia, Canada. The climatic conditions in this catchment present an interesting set of modelling challenges; daily variations and seasonal changes in temperature, snowfall and retention result in great difficulty for runoff prediction by means of a data-driven approach. Data from 10 years of daily observations are used in the present study (01/01/2000-31/12/2009): comprising [i] discharge, [ii] total rainfall (excluding snowfall), [iii] total snowfall, [iv] thickness of snow cover, and [v] maximum and [vi] minimum temperature. Precipitation occurs throughout the whole year being slightly lower during summer. Snowfall is common from November until April and rare hurricane weather may occur in autumn. The average maximum temperature is below 0 0C in January and February, but significant

  1. Synthesis of AuPd alloyed nanoparticles via room-temperature electron reduction with argon glow discharge as electron source.

    Science.gov (United States)

    Yang, Manman; Wang, Zongyuan; Wang, Wei; Liu, Chang-Jun

    2014-01-01

    Argon glow discharge has been employed as a cheap, environmentally friendly, and convenient electron source for simultaneous reduction of HAuCl4 and PdCl2 on the anodic aluminum oxide (AAO) substrate. The thermal imaging confirms that the synthesis is operated at room temperature. The reduction is conducted with a short time (30 min) under the pressure of approximately 100 Pa. This room-temperature electron reduction operates in a dry way and requires neither hydrogen nor extra heating nor chemical reducing agent. The analyses using X-ray photoelectron spectroscopy (XPS) confirm all the metallic ions have been reduced. The characterization with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) shows that AuPd alloyed nanoparticles are formed. There also exist some highly dispersed Au and Pd monometallic particles that cannot be detected by XRD and transmission electron microscopy (TEM) because of their small particle sizes. The observed AuPd alloyed nanoparticles are spherical with an average size of 14 nm. No core-shell structure can be observed. The room-temperature electron reduction can be operated in a larger scale. It is an easy way for the synthesis of AuPd alloyed nanoparticles.

  2. Thick-Film and LTCC Passive Components for High-Temperature Electronics

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2013-04-01

    Full Text Available At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors made in thick-film or Low-Temperature Co-fired Ceramics (LTCC technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors suitable for the temperature range between 150°C and 400°C.

  3. Generalized Lenard-Balescu calculations of electron-ion temperature relaxation in beryllium plasma.

    Science.gov (United States)

    Fu, Zhen-Guo; Wang, Zhigang; Li, Da-Fang; Kang, Wei; Zhang, Ping

    2015-09-01

    The problem of electron-ion temperature relaxation in beryllium plasma at various densities (0.185-18.5g/cm^{3}) and temperatures [(1.0-8)×10^{3} eV] is investigated by using the generalized Lenard-Balescu theory. We consider the correlation effects between electrons and ions via classical and quantum static local field corrections. The numerical results show that the electron-ion pair distribution function at the origin approaches the maximum when the electron-electron coupling parameter equals unity. The classical result of the Coulomb logarithm is in agreement with the quantum result in both the weak (Γ_{ee}1) electron-electron coupling ranges, whereas it deviates from the quantum result at intermediate values of the coupling parameter (10^{-2}Coulomb logarithm will decrease and the corresponding relaxation rate ν_{ie} will increase. In addition, a simple fitting law ν_{ie}/ν_{ie}^{(0)}=a(ρ_{Be}/ρ_{0})^{b} is determined, where ν_{ie}^{(0)} is the relaxation rate corresponding to the normal metal density of Be and ρ_{0}, a, and b are the fitting parameters related to the temperature and the degree of ionization 〈Z〉 of the system. Our results are expected to be useful for future inertial confinement fusion experiments involving Be plasma.

  4. River runoff influences on the Central Mediterranean overturning circulation

    Science.gov (United States)

    Verri, Giorgia; Pinardi, N.; Oddo, P.; Ciliberti, S. A.; Coppini, G.

    2018-03-01

    The role of riverine freshwater inflow on the Central Mediterranean Overturning Circulation (CMOC) was studied using a high-resolution ocean model with a complete distribution of rivers in the Adriatic and Ionian catchment areas. The impact of river runoff on the Adriatic and Ionian Sea basins was assessed by a twin experiment, with and without runoff, from 1999 to 2012. This study tries to show the connection between the Adriatic as a marginal sea containing the downwelling branch of the anti-estuarine CMOC and the large runoff occurring there. It is found that the multiannual CMOC is a persistent anti-estuarine structure with secondary estuarine cells that strengthen in years of large realistic river runoff. The CMOC is demonstrated to be controlled by wind forcing at least as much as by buoyancy fluxes. It is found that river runoff affects the CMOC strength, enhancing the amplitude of the secondary estuarine cells and reducing the intensity of the dominant anti-estuarine cell. A large river runoff can produce a positive buoyancy flux without switching off the antiestuarine CMOC cell, but a particularly low heat flux and wind work with normal river runoff can reverse it. Overall by comparing experiments with, without and with unrealistically augmented runoff we demonstrate that rivers affect the CMOC strength but they can never represent its dominant forcing mechanism and the potential role of river runoff has to be considered jointly with wind work and heat flux, as they largely contribute to the energy budget of the basin. Looking at the downwelling branch of the CMOC in the Adriatic basin, rivers are demonstrated to locally reduce the volume of Adriatic dense water formed in the Southern Adriatic Sea as a result of increased water stratification. The spreading of the Adriatic dense water into the Ionian abyss is affected as well: dense waters overflowing the Otranto Strait are less dense in a realistic runoff regime, with respect to no runoff experiment, and

  5. Bayesian analyses of seasonal runoff forecasts

    Science.gov (United States)

    Krzysztofowicz, R.; Reese, S.

    1991-12-01

    Forecasts of seasonal snowmelt runoff volume provide indispensable information for rational decision making by water project operators, irrigation district managers, and farmers in the western United States. Bayesian statistical models and communication frames have been researched in order to enhance the forecast information disseminated to the users, and to characterize forecast skill from the decision maker's point of view. Four products are presented: (i) a Bayesian Processor of Forecasts, which provides a statistical filter for calibrating the forecasts, and a procedure for estimating the posterior probability distribution of the seasonal runoff; (ii) the Bayesian Correlation Score, a new measure of forecast skill, which is related monotonically to the ex ante economic value of forecasts for decision making; (iii) a statistical predictor of monthly cumulative runoffs within the snowmelt season, conditional on the total seasonal runoff forecast; and (iv) a framing of the forecast message that conveys the uncertainty associated with the forecast estimates to the users. All analyses are illustrated with numerical examples of forecasts for six gauging stations from the period 1971 1988.

  6. Evolution of the electron temperature profile of ohmically heated plasmas in TFTR

    International Nuclear Information System (INIS)

    Taylor, G.; Efthimion, P.C.; Arunasalam, V.

    1985-08-01

    Blackbody electron cyclotron emission was used to ascertain and study the evolution and behavior of the electron temperature profile in ohmically heated plasmas in the Tokamak Fusion Test Reactor (TFTR). The emission was measured with absolutely calibrated millimeter wavelength radiometers. The temperature profile normalized to the central temperature and minor radius is observed to broaden substantially with decreasing limiter safety factor q/sub a/, and is insensitive to the plasma minor radius. Sawtooth activity was seen in the core of most TFTR discharges and appeared to be associated with a flattening of the electron temperature profile within the plasma core where q less than or equal to 1. Two types of sawtooth behavior were identified in large TFTR plasmas (minor radius, a less than or equal to 0.8 m) : a typically 35 to 40 msec period ''normal'' sawtooth, and a ''compound'' sawtooth with 70 to 80 msec period

  7. Impact of climate change on runoff in Lake Urmia basin, Iran

    Science.gov (United States)

    Sanikhani, Hadi; Kisi, Ozgur; Amirataee, Babak

    2018-04-01

    Investigation of the impact of climate change on water resources is very necessary in dry and arid regions. In the first part of this paper, the climate model Long Ashton Research Station Weather Generator (LARS-WG) was used for downscaling climate data including rainfall, solar radiation, and minimum and maximum temperatures. Two different case studies including Aji-Chay and Mahabad-Chay River basins as sub-basins of Lake Urmia in the northwest part of Iran were considered. The results indicated that the LARS-WG successfully downscaled the climatic variables. By application of different emission scenarios (i.e., A1B, A2, and B1), an increasing trend in rainfall and a decreasing trend in temperature were predicted for both the basins over future time periods. In the second part of this paper, gene expression programming (GEP) was applied for simulating runoff of the basins in the future time periods including 2020, 2055, and 2090. The input combination including rainfall, solar radiation, and minimum and maximum temperatures in current and prior time was selected as the best input combination with highest predictive power for runoff prediction. The results showed that the peak discharge will decrease by 50 and 55.9% in 2090 comparing with the baseline period for the Aji-Chay and Mahabad-Chay basins, respectively. The results indicated that the sustainable adaptation strategies are necessary for these basins for protection of water resources in future.

  8. High temperature, radiation hardened electronics for application to nuclear power plants

    International Nuclear Information System (INIS)

    Gover, J.E.

    1980-01-01

    Electronic circuits were developed and built at Sandia for many aerospace and energy systems applications. Among recent developments were high temperature electronics for geothermal well logging and radiation hardened electronics for a variety of aerospace applications. Sandia has also been active in technology transfer to commercial industry in both of these areas

  9. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Pérez, Marco, E-mail: qimfranco@hotmail.com, E-mail: jlgm@xanum.uam.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México D. F. 09340 (Mexico); Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Gázquez, José L., E-mail: qimfranco@hotmail.com, E-mail: jlgm@xanum.uam.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México D. F. 09340 (Mexico); Ayers, Paul W. [Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Vela, Alberto [Departamento de Química, Centro de Investigación y de Estudios Avanzados (Cinvestav), Av. Instituto Politécnico Nacional 2508, México D. F. 07360 (Mexico)

    2015-10-21

    We extend the definition of the electronic chemical potential (μ{sub e}) and chemical hardness (η{sub e}) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μ{sub e}. Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (−I), positive (−A), and zero values of the fractional charge (−(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness.

  10. Multi-scale response of runoff to climate fluctuation in the headwater region of Kaidu River in Xinjiang of China

    Science.gov (United States)

    Bai, Ling; Chen, Zhongsheng; Xu, Jianhua; Li, Weihong

    2016-08-01

    Based on the hydrological and meteorological data in the headwater region of the Kaidu River during 1960-2009, the multi-scale characteristics of runoff variability were analyzed using the ensemble empirical mode decomposition method (EEMD), and the aim is to investigate the oscillation mode structure characteristics of runoff change and its response to climate fluctuation at different time scales. Results indicated that in the past 50 years, the overall runoff of Kaidu River in Xinjiang has showed a significant nonlinear upward trend, and its changes have obviously exhibited an inter-annual scale (quasi-3 and quasi-6-year) and inter-decadal scale (quasi-10 and quasi-25-year). Variance contribution rates of each component manifested that the inter-decadal change had been playing a more important role in the overall runoff change for Kaidu River, and the reconstructed inter-annual variation trend could describe the fluctuation state of the original runoff anomaly during the study period. The reconstructed inter-decadal variability effectively revealed that the runoff for Kaidu River changed over the years, namely the states of abundance and low water period appear alternately. In addition, we found that runoff has a positive correlation to precipitation and temperature at different time scales, but they are most significant and relevant at inter-decadal scale, indicating the inter-decadal scale is most suitable for investigating the responses of runoff dynamics to climate fluctuation. At the same time, the results also suggested that EEMD is an effective method to analyze the multi-scale characteristics of nonlinear and non-stationary signal.

  11. Surface runoff in the Itaim Watershed

    Directory of Open Access Journals (Sweden)

    Getulio Teixeira Batista

    2007-06-01

    Full Text Available This paper describes a work done in the Itaim watershed at Taubaté, SP, and had the objective of estimating the surface runoff based on the Curve-Number (CN method in area with vegetation cover of grassland (Brachiaria Decumbens, that prevails in this watershed. The surface runoff was estimated using three different methods: 1st values of accumulated Infiltration (IAc obtained in the field were used, considered as the Potential Infiltration (S, which varied from 15.37 mm to 51.88 mm with an average value of 23.46 mm. With those measured infiltration rates and using the maximum precipitation values for Taubaté, SP, with duration time of 3 hours: P = 54.4; 70.3; 80.8; 86.7; 90.9; 94.1 and 103.9 mm, respectively, for the return times, Tr = 2, 5, 10, 15, 25, 50 and 100 years, the following values of surface runoff were generated: 34.83; 49.33; 59.14; 64.71; 68.69; 71.73 and 81.10 mm, respectively; In the 2nd method it was considered that the prevailing vegetation cover of the watershed was Dirty Pasture (Pasture with regrowth of natural vegetation and therefore, a value of CN = 75 was used and generated a potential infiltration, S = 84,7 mm and resulted in surface runoff values that varied from 11 to 44 mm; In the 3rd method, the value of CN was considered equal to 66.57. This value was calculated weighting the contribution of all land use cover classes of the watershed, and as a result a higher value of potential infiltration, S = 127 mm, was obtained. Consequently, the surface runoff values were 5.33; 11.64; 16.72; 19.83; 22.16; 23.98 and 29.83 mm, respectively. Therefore, the comparison with the results obtained by the two Curve-Number methods (conventional and weighted allowed to be concluded that the Curve-Number method applied in a conventional way underestimated the surface runoff in the studied area. However, results indicate that it is possible to use this method for surface runoff estimates as long as adjustments based on potential

  12. Electron temperatures within magnetic clouds between 2 and 4 AU: Voyager 2 observations

    Science.gov (United States)

    Sittler, E. C.; Burlaga, L. F.

    1998-08-01

    We have performed an analysis of Voyager 2 plasma electron observations within magnetic clouds between 2 and 4 AU identified by Burlaga and Behannon [1982]. The analysis has been confined to three of the magnetic clouds identified by Burlaga and Behannon that had high-quality data. The general properties of the plasma electrons within a magnetic cloud are that (1) the moment electron temperature anticorrelates with the electron density within the cloud, (2) the ratio Te/Tp tends to be >1, and (3) on average, Te/Tp~7.0. All three results are consistent with previous electron observations within magnetic clouds. Detailed analyses of the core and halo populations within the magnetic clouds show no evidence of either an anticorrelation between the core temperature TC and the electron density Ne or an anticorrelation between the halo temperature TH and the electron density. Within the magnetic clouds the halo component can contribute more than 50% of the electron pressure. The anticorrelation of Te relative to Ne can be traced to the density of the halo component relative to the density of the core component. The core electrons dominate the electron density. When the density goes up, the halo electrons contribute less to the electron pressure, so we get a lower Te. When the electron density goes down, the halo electrons contribute more to the electron pressure, and Te goes up. We find a relation between the electron pressure and density of the form Pe=αNeγ with γ~0.5.

  13. [Research on evaluation of water quality of Beijing urban stormwater runoff].

    Science.gov (United States)

    Hou, Pei-Qiang; Ren, Yu-Fen; Wang, Xiao-Ke; Ouyang, Zhi-Yun; Zhou, Xiao-Ping

    2012-01-01

    The natural rainwater and stormwater runoff samples from three underlying surfaces (rooftop, campus road and ring road) were sampled and analyzed from July to October, 2010 in Beijing. Eight rainfall events were collected totally and thirteen water quality parameters were measured in each event. Grey relationship analysis and principal component analysis were applied to assess composite water quality and identify the main pollution sources of stormwater runoff. The results show that the composite water quality of ring road runoff is mostly polluted, and then is rooftop runoff, campus road runoff and rainwater, respectively. The composite water quality of ring road runoff is inferior to V class of surface water, while rooftop runoff, campus road runoff and rainwater are in II class of surface water. The mean concentration of TN and NH4(+)-N in rainwater and runoff is 5.49-11.75 mg x L(-1) and 2.90-5.67 mg x L(-1), respectively, indicating that rainwater and runoff are polluted by nitrogen (N). Two potential pollution sources are identified in ring road runoff: (1) P, SS and organic pollutant are possibly related to debris which is from vehicle tyre and material of ring road; (2) N and dissolved metal have relations with automobile exhaust emissions and bulk deposition.

  14. Nonlocal effects in a bounded low-temperature plasma with fast electrons

    International Nuclear Information System (INIS)

    DeJoseph, C. A. Jr.; Demidov, V. I.; Kudryavtsev, A. A.

    2007-01-01

    Effects associated with nonlocality of the electron energy distribution function (EEDF) in a bounded, low-temperature plasma containing fast electrons, can lead to a significant increase in the near-wall potential drop, leading to self-trapping of fast electrons in the plasma volume, even if the density of this group is only a small fraction (∼0.001%) of the total electron density. If self-trapping occurs, the fast electrons can substantially increase the rate of stepwise excitation, supply additional heating to slow electrons, and reduce their rate of diffusion cooling. Altering the source terms of these fast electrons will, therefore, alter the near-wall sheath and, through modification of the EEDF, a number of plasma parameters. Self-trapping of fast electrons is important in a variety of plasmas, including hollow-cathode discharges and capacitive rf discharges, and is especially pronounced in an afterglow plasma, which is a key phase of any pulse-modulated discharge. In the afterglow, the electron temperature is less than a few tenths of an electron volt, and the fast electrons will have energies typically greater than an electron volt. It is shown that in the afterglow plasma of noble gases, fast electrons, arising from Penning ionization of metastable atoms, can lead to the above condition and significantly change the plasma and sheath properties. Similar effects can be important in technologically relevant electronegative gas plasmas, where fast electrons can arise due to electron detachment in collisions of negative ions with atomic species. Both experimental and modeling results are presented to illustrate these effects

  15. The electron density and temperature distributions predicted by bow shock models of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Noriega-Crespo, A.; Bohm, K.H.; Raga, A.C.

    1990-01-01

    The observable spatial electron density and temperature distributions for series of simple bow shock models, which are of special interest in the study of Herbig-Haro (H-H) objects are computed. The spatial electron density and temperature distributions are derived from forbidden line ratios. It should be possible to use these results to recognize whether an observed electron density or temperature distribution can be attributed to a bow shock, as is the case in some Herbig-Haro objects. As an example, the empirical and predicted distributions for H-H 1 are compared. The predicted electron temperature distributions give the correct temperature range and they show very good diagnostic possibilities if the forbidden O III (4959 + 5007)/4363 wavelength ratio is used. 44 refs

  16. The impact of global warming on river runoff

    Science.gov (United States)

    Miller, James R.; Russell, Gary L.

    1992-01-01

    A global atmospheric model is used to calculate the annual river runoff for 33 of the world's major rivers for the present climate and for a doubled CO2 climate. The model has a horizontal resolution of 4 x 5 deg, but the runoff from each model grid box is quartered and added to the appropriate river drainage basin on a 2 x 2.5 deg resolution. The computed runoff depends on the model's precipitation, evapotranspiration, and soil moisture storage. For the doubled CO2 climate, the runoff increased for 25 of the 33 rivers, and in most cases the increases coincide with increased rainfall within the drainage basins. There were runoff increases in all rivers in high northern latitudes, with a maximum increase of 47 percent. At low latitudes there were both increases and decreases ranging from a 96 increase to a 43 percent decrease. The effect of the simplified model assumptions of land-atmosphere interactions on the results is discussed.

  17. Spectral measurements of electron temperature in nonequilibrium highly ionized He plasma

    International Nuclear Information System (INIS)

    Korshunov, O V; Chinnov, V F; Kavyrshin, D I; Ageev, A G

    2016-01-01

    It has been experimentally shown that highly ionized He arc plasma does not achieve local thermodynamic equilibrium expected for plasmas with electron concentrations above 1 × 10 16 cm -3 like argon plasma. We have found that the reason for this deviation is strong nonisotropy of plasma. Triple electron recombination with temperatures of 2.5-3 eV is almost absent. Charged particles move from the arc ( r = 1 mm) to chamber walls due to ambipolar diffusion creating ionization nonequilibrium over the excited states rendering Boltzmann distribution and Saha equation inapplicable for determining electron temperature. A method for determining electron temperature is suggested that is based on using the relative intensities of the atomic and ion lines. Its advantage lies in an energy gap between these lines’ states over 50 eV that reduces the influence of nonequilibrium on the result. This influence can be taken into account if the ionization energies of emitting states of atom and ion have close values. The suggested method can be expanded for any media including those with dimensional nonisotropy that have both atomic and ion lines in their emission spectra. (paper)

  18. An Overview of Rainfall-Runoff Model Types

    Science.gov (United States)

    This report explores rainfall-runoff models, their generation methods, and the categories under which they fall. Runoff plays an important role in the hydrological cycle by returning excess precipitation to the oceans and controlling how much water flows into stream systems. Mode...

  19. Bivariate Rainfall and Runoff Analysis Using Shannon Entropy Theory

    Science.gov (United States)

    Rahimi, A.; Zhang, L.

    2012-12-01

    Rainfall-Runoff analysis is the key component for many hydrological and hydraulic designs in which the dependence of rainfall and runoff needs to be studied. It is known that the convenient bivariate distribution are often unable to model the rainfall-runoff variables due to that they either have constraints on the range of the dependence or fixed form for the marginal distributions. Thus, this paper presents an approach to derive the entropy-based joint rainfall-runoff distribution using Shannon entropy theory. The distribution derived can model the full range of dependence and allow different specified marginals. The modeling and estimation can be proceeded as: (i) univariate analysis of marginal distributions which includes two steps, (a) using the nonparametric statistics approach to detect modes and underlying probability density, and (b) fitting the appropriate parametric probability density functions; (ii) define the constraints based on the univariate analysis and the dependence structure; (iii) derive and validate the entropy-based joint distribution. As to validate the method, the rainfall-runoff data are collected from the small agricultural experimental watersheds located in semi-arid region near Riesel (Waco), Texas, maintained by the USDA. The results of unviariate analysis show that the rainfall variables follow the gamma distribution, whereas the runoff variables have mixed structure and follow the mixed-gamma distribution. With this information, the entropy-based joint distribution is derived using the first moments, the first moments of logarithm transformed rainfall and runoff, and the covariance between rainfall and runoff. The results of entropy-based joint distribution indicate: (1) the joint distribution derived successfully preserves the dependence between rainfall and runoff, and (2) the K-S goodness of fit statistical tests confirm the marginal distributions re-derived reveal the underlying univariate probability densities which further

  20. 49 CFR 213.59 - Elevation of curved track; runoff.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Elevation of curved track; runoff. 213.59 Section... track; runoff. (a) If a curve is elevated, the full elevation shall be provided throughout the curve, unless physical conditions do not permit. If elevation runoff occurs in a curve, the actual minimum...

  1. MIXING THE SOLAR WIND PROTON AND ELECTRON SCALES: EFFECTS OF ELECTRON TEMPERATURE ANISOTROPY ON THE OBLIQUE PROTON FIREHOSE INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Maneva, Y.; Lazar, M.; Poedts, S. [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Heverlee (Belgium); Viñas, A., E-mail: yana.maneva@wis.kuleuven.be [NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, MD 20771 (United States)

    2016-11-20

    The double adiabatic expansion of the nearly collisionless solar wind plasma creates conditions for the firehose instability to develop and efficiently prevent the further increase of the plasma temperature in the direction parallel to the interplanetary magnetic field. The conditions imposed by the firehose instability have been extensively studied using idealized approaches that ignore the mutual effects of electrons and protons. Recently, more realistic approaches have been proposed that take into account the interplay between electrons and protons, unveiling new regimes of the parallel oscillatory modes. However, for oblique wave propagation the instability develops distinct branches that grow much faster and may therefore be more efficient than the parallel firehose instability in constraining the temperature anisotropy of the plasma particles. This paper reports for the first time on the effects of electron plasma properties on the oblique proton firehose (PFH) instability and provides a comprehensive vision of the entire unstable wave-vector spectrum, unifying the proton and the smaller electron scales. The plasma β and temperature anisotropy regimes considered here are specific for the solar wind and magnetospheric conditions, and enable the electrons and protons to interact via the excited electromagnetic fluctuations. For the selected parameters, simultaneous electron and PFH instabilities can be observed with a dispersion spectrum of the electron firehose (EFH) extending toward the proton scales. Growth rates of the PFH instability are markedly boosted by the anisotropic electrons, especially in the oblique direction where the EFH growth rates are orders of magnitude higher.

  2. Mixing the Solar Wind Proton and Electron Scales: Effects of Electron Temperature Anisotropy on the Oblique Proton Firehose Instability

    Science.gov (United States)

    Maneva, Y.; Lazar, M.; Vinas, A.; Poedts, S.

    2016-01-01

    The double adiabatic expansion of the nearly collisionless solar wind plasma creates conditions for the firehose instability to develop and efficiently prevent the further increase of the plasma temperature in the direction parallel to the interplanetary magnetic field. The conditions imposed by the firehose instability have been extensively studied using idealized approaches that ignore the mutual effects of electrons and protons. Recently, more realistic approaches have been proposed that take into account the interplay between electrons and protons,? unveiling new regimes of the parallel oscillatory modes. However, for oblique wave propagation the instability develops distinct branches that grow much faster and may therefore be more efficient than the parallel firehose instability in constraining the temperature anisotropy of the plasma particles. This paper reports for the first time on the effects of electron plasma properties on the oblique proton firehose (PFH) instability and provides a comprehensive vision of the entire unstable wave-vector spectrum, unifying the proton and the smaller electron scales. The plasma ß and temperature anisotropy regimes considered here are specific for the solar wind and magnetospheric conditions, and enable the electrons and protons to interact via the excited electromagnetic fluctuations. For the selected parameters, simultaneous electron and PFH instabilities can be observed with a dispersion spectrum of the electron firehose (EFH) extending toward the proton scales. Growth rates of the PFH instability are markedly boosted by the anisotropic electrons, especially in the oblique direction where the EFH growth rates are orders of magnitude higher.

  3. Electronic Modeling and Design for Extreme Temperatures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop electronics for operation at temperatures that range from -230oC to +130oC. This new technology will minimize the requirements for external...

  4. A Harsh Environment Wireless Pressure Sensing Solution Utilizing High Temperature Electronics

    Science.gov (United States)

    Yang, Jie

    2013-01-01

    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. PMID:23447006

  5. Temperature dependence of electron concentration in cadmium arsenide

    NARCIS (Netherlands)

    Gelten, M.J.; Blom, F.A.P.

    1979-01-01

    From measurements of the temperature dependence of the electron concentration in Cd 3 As 2 , we found values for the conduction-band parameters that are in good agreement with those recently reported by Aubin, Caron, and Jay-Gerin. However, in contrast with these authors we found no small overlap,

  6. Oblique ion-acoustic cnoidal waves in two temperature superthermal electrons magnetized plasma

    International Nuclear Information System (INIS)

    Panwar, A.; Ryu, C. M.; Bains, A. S.

    2014-01-01

    A study is presented for the oblique propagation of ion acoustic cnoidal waves in a magnetized plasma consisting of cold ions and two temperature superthermal electrons modelled by kappa-type distributions. Using the reductive perturbation method, the nonlinear Korteweg de-Vries equation is derived, which further gives the solutions with a special type of cnoidal elliptical functions. Both compressive and rarefactive structures are found for these cnoidal waves. Nonlinear periodic cnoidal waves are explained in terms of plasma parameters depicting the Sagdeev potential and the phase curves. It is found that the density ratio of hot electrons to ions μ significantly modifies compressive/refractive wave structures. Furthermore, the combined effects of superthermality of cold and hot electrons κ c ,κ h , cold to hot electron temperature ratio σ, angle of propagation and ion cyclotron frequency ω ci have been studied in detail to analyze the height and width of compressive/refractive cnoidal waves. The findings in the present study could have important implications in understanding the physics of electrostatic wave structures in the Saturn's magnetosphere where two temperature superthermal electrons are present

  7. Simplified Laboratory Runoff Procedure (SLRP): Procedure and Application

    National Research Council Canada - National Science Library

    Price, Richard

    2000-01-01

    The Simplified Laboratory Runoff Procedure (SLRP) was developed to provide a faster, less expensive approach to evaluate surface runoff water quality from dredged material placed in an upland environment...

  8. Regulation of electron temperature gradient turbulence by zonal flows driven by trapped electron modes

    Science.gov (United States)

    Asahi, Y.; Ishizawa, A.; Watanabe, T.-H.; Tsutsui, H.; Tsuji-Iio, S.

    2014-05-01

    Turbulent transport caused by electron temperature gradient (ETG) modes was investigated by means of gyrokinetic simulations. It was found that the ETG turbulence can be regulated by meso-scale zonal flows driven by trapped electron modes (TEMs), which are excited with much smaller growth rates than those of ETG modes. The zonal flows of which radial wavelengths are in between the ion and the electron banana widths are not shielded by trapped ions nor electrons, and hence they are effectively driven by the TEMs. It was also shown that an E × B shearing rate of the TEM-driven zonal flows is larger than or comparable to the growth rates of long-wavelength ETG modes and TEMs, which make a main contribution to the turbulent transport before excitation of the zonal flows.

  9. Electron-temperature-gradient-driven drift waves and anomalous electron energy transport

    International Nuclear Information System (INIS)

    Shukla, P.K.; Murtaza, G.; Weiland, J.

    1990-01-01

    By means of a kinetic description for ions and Braginskii's fluid model for electrons, three coupled nonlinear equations governing the dynamics of low-frequency short-wavelength electrostatic waves in the presence of equilibrium density temperature and magnetic-field gradients in a two-component magnetized plasma are derived. In the linear limit a dispersion relation that admits new instabilities of drift waves is presented. An estimate of the anomalous electron energy transport due to non-thermal drift waves is obtained by making use of the saturated wave potential, which is deduced from the mixing-length hypothesis. Stationary solutions of the nonlinear equations governing the interaction of linearly unstable drift waves are also presented. The relevance of this investigation to wave phenomena in space and laboratory plasmas is pointed out. (author)

  10. Urban runoff and combined sewer overflow. [Wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Moffa, P.E. (Calocerinos and Spina, Liverpool, NY); Freedman, S.D.; Owens, E.M.; Field, R.; Cibik, C.

    1982-06-01

    The control, treatment and management of urban runoff and sewer overflow are reviewed. Simplified modeling and monitoring techniques are used to characterize urban runoff and to assess control alternatives. (KRM)

  11. Snowmelt runoff in the Green River basin derived from MODIS snow extent

    Science.gov (United States)

    Barton, J. S.; Hall, D. K.

    2011-12-01

    The Green River represents a vital water supply for southwestern Wyoming, northern Colorado, eastern Utah, and the Lower Colorado River Compact states (Arizona, Nevada, and California). Rapid development in the southwestern United States combined with the recent drought has greatly stressed the water supply of the Colorado River system, and concurrently increased the interest in long-term variations in stream flow. Modeling of snowmelt runoff represents a means to predict flows and reservoir storage, which is useful for water resource planning. An investigation is made into the accuracy of the Snowmelt Runoff Model of Martinec and Rango, driven by Moderate Resolution Imaging Spectroradiometer (MODIS) snow maps for predicting stream flow within the Green River basin. While the moderate resolution of the MODIS snow maps limits the spatial detail that can be captured, the daily coverage is an important advantage of the MODIS imagery. The daily MODIS snow extent is measured using the most recent clear observation for each 500-meter pixel. Auxiliary data used include temperature and precipitation time series from the Snow Telemetry (SNOTEL) and Remote Automated Weather Station (RAWS) networks as well as from National Weather Service records. Also from the SNOTEL network, snow-water equivalence data are obtained to calibrate the conversion between snow extent and runoff potential.

  12. Managing urban runoff in residential neighborhoods: Nitrogen and phosphorus in lawn irrigation driven runoff

    Science.gov (United States)

    Occhipinti, Marti L.; Yang, Yun-Ya; Majcherek, Tammy; Haver, Darren; Oki, Lorence

    2017-01-01

    Sources and mechanisms of nutrient transport in lawn irrigation driven surface runoff are largely unknown. We investigated the transport of nitrogen (N) and phosphorus (P) in lawn irrigation driven surface runoff from a residential neighborhood (28 ha) of 56% impervious and 44% pervious areas. Pervious areas encompassing turfgrass (lawns) in the neighborhood were irrigated with the reclaimed water in common areas during the evening to late night and with the municipal water in homeowner’s lawns during the morning. The stormwater outlet pipe draining the residential neighborhood was instrumented with a flow meter and Hach autosampler. Water samples were collected every 1-h and triple composite samples were obtained at 3-h intervals during an intensive sampling period of 1-week. Mean concentrations, over 56 sampling events, of total N (TN) and total P (TP) in surface runoff at the outlet pipe were 10.9±6.34 and 1.3±1.03 mg L–1, respectively. Of TN, the proportion of nitrate–N was 58% and other–N was 42%, whereas of TP, orthophosphate–P was 75% and other–P was 25%. Flow and nutrient (N and P) concentrations were lowest from 6:00 a.m. to noon, which corresponded with the use of municipal water and highest from 6:00 p.m. to midnight, which corresponded with the use of reclaimed water. This data suggests that N and P originating in lawn irrigation driven surface runoff from residential catchments is an important contributor of nutrients in surface waters. PMID:28604811

  13. Role of temperature on static correlational properties in a spin-polarized electron gas

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Priya; Moudgil, R. K., E-mail: rkmoudgil@kuk.ac.in [Department of Physics, Kurukshetra University, Kurukshetra – 136 119 (India); Kumar, Krishan [S. D. College (Lahore), Ambala Cantt. - 133001 (India)

    2016-05-06

    We have studied the effect of temperature on the static correlational properties of a spin-polarized three-dimensional electron gas (3DEG) over a wide coupling and temperature regime. This problem has been very recently studied by Brown et al. using the restricted path-integral Monte Carlo (RPIMC) technique in the warm-dense regime. To this endeavor, we have used the finite temperature version of the dynamical mean-field theory of Singwi et al, the so-called quantum STLS (qSTLS) approach. The static density structure factor and the static pair-correlation function are calculated, and compared with the RPIMC simulation data. We find an excellent agreement with the simulation at high temperature over a wide coupling range. However, the agreement is seen to somewhat deteriorate with decreasing temperature. The pair-correlation function is found to become small negative for small electron separation. This may be attributed to the inadequacy of the mean-field theory in dealing with the like spin electron correlations in the strong-coupling domain. A nice agreement with RPIMC data at high temperature seems to arise due to weakening of both the exchange and coulomb correlations with rising temperature.

  14. The Idiosyncrasies of Storage and Implications for Catchment Runoff (Invited)

    Science.gov (United States)

    Spence, C.

    2010-12-01

    Because water goes into storage when it rains, perhaps the entire concept of a direct rainfall-runoff process is erroneous and misleading. Perhaps the runoff generation process is merely the conversion of storage to runoff. Using this perspective as a foundation, it then becomes important to understand how catchments retain water, where this storage is distributed and what controls the distribution of this storage. There is a growing body of observational evidence that the idiosyncrasies of storage in the catchment are crucial for runoff generation. These idiosyncrasies are important enough that some hydrologists are questioning assumptions of steady state, linearity, and topographic control in existing theories and algorithms of runoff generation. For instance, thresholds that control the release of water have been identified at many scales and in many landscapes. Hysteresis in storage-runoff relationships at all scales manifest because of these thresholds. Because storage thresholds at a range of scales are now known to be important for runoff response, connectivity has become an important concept crucial to interpreting catchment runoff response. There appears to be growing acceptance of such ideas as thresholds, hysteresis and connectivity in the hydrological literature. Theoretical development and model parameterization have begun, but there remains much work to resolve these field observations. In particular, our community should strive to investigate the relevance of storage-runoff relationships partly through innovative measurement techniques and the development of model structures appropriate for the requisite testing of these theories in a diversity of landscapes.

  15. Runoff scenarios of the Ötz catchment (Tyrol, Austria) considering climate change driven changes of the cryosphere

    Science.gov (United States)

    Helfricht, Kay; Schneeberger, Klaus; Welebil, Irene; Schöber, Johannes; Huss, Matthias; Formayer, Herbert; Huttenlau, Matthias; Schneider, Katrin

    2014-05-01

    The seasonal distribution of runoff in alpine catchments is markedly influenced by the cryospheric contribution (snow and ice). Long-term climate change will alter these reservoirs and consequently have an impact on the water balance. Glacierized catchments like the Ötztal (Tyrol, Austria) are particularly sensitive to changes in the cryosphere and the hydrological changes related to them. The Ötztal possesses an outstanding role in Austrian and international cryospheric research and reacts sensitive to changes in hydrology due to its socio-economic structure (e.g. importance of tourism, hydro-power). In this study future glacier scenarios for the runoff calculations in the Ötztal catchment are developed. In addition to climatological scenario data, glacier scenarios were established for the hydrological simulation of future runoff. Glacier outlines and glacier surface elevation changes of the Austrian Glacier Inventory were used to derive present ice thickness distribution and scenarios of glacier area distribution. Direct effects of climate change (i.e. temperature and precipitation change) and indirect effects in terms of variations in the cryosphere were considered for the analysis of the mean runoff and particularly flood frequencies. Runoff was modelled with the hydrological model HQSim, which was calibrated for the runoff gauges at Brunau, Obergurgl and Vent. For a sensitivity study, the model was driven by separate glacier scenarios. Keeping glacier area constant, variable climate input was used to separate the effect of climate sensitivity. Results of the combination of changed glacier areas and changed climate input were subsequently analysed. Glacier scenarios show first a decrease in volume, before glacier area shrinks. The applied method indicates a 50% ice volume loss by 2050 relative to today. Further, model results show a reduction in glacier volume and area to less than 20% of the current ice cover towards the end of the 21st century. The effect

  16. Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures less than 1 keV

    Energy Technology Data Exchange (ETDEWEB)

    Ross, James Steven [Univ. of California, San Diego, CA (United States)

    2010-01-01

    Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (Te < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 1020cm-3 are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.

  17. Electron spectroscopy on high-temperature superconductors and related compounds

    International Nuclear Information System (INIS)

    Knupfer, M.

    1994-01-01

    In the last two classes of materials have been discovered which distinguish themselves due to a transition into the superconducting state at relatively high temperatures. These are the cuprate superconductors and the alkali metal doped fullerenes. In this work the electronic structure of representatives of these materials, undoped and Ca-doped YBa 2 Cu 4 O 8 and A 3 C 60 (A=K, Rb), has been investigated using electron energy-loss spectroscopy and photoemission spectroscopy. (orig.) [de

  18. Determination of equilibrium electron temperature and times using an electron swarm model with BOLSIG+ calculated collision frequencies and rate coefficients

    International Nuclear Information System (INIS)

    Pusateri, Elise N.; Morris, Heidi E.; Nelson, Eric M.; Ji, Wei

    2015-01-01

    Electromagnetic pulse (EMP) events produce low-energy conduction electrons from Compton electron or photoelectron ionizations with air. It is important to understand how conduction electrons interact with air in order to accurately predict EMP evolution and propagation. An electron swarm model can be used to monitor the time evolution of conduction electrons in an environment characterized by electric field and pressure. Here a swarm model is developed that is based on the coupled ordinary differential equations (ODEs) described by Higgins et al. (1973), hereinafter HLO. The ODEs characterize the swarm electric field, electron temperature, electron number density, and drift velocity. Important swarm parameters, the momentum transfer collision frequency, energy transfer collision frequency, and ionization rate, are calculated and compared to the previously reported fitted functions given in HLO. These swarm parameters are found using BOLSIG+, a two term Boltzmann solver developed by Hagelaar and Pitchford (2005), which utilizes updated cross sections from the LXcat website created by Pancheshnyi et al. (2012). We validate the swarm model by comparing to experimental effective ionization coefficient data in Dutton (1975) and drift velocity data in Ruiz-Vargas et al. (2010). In addition, we report on electron equilibrium temperatures and times for a uniform electric field of 1 StatV/cm for atmospheric heights from 0 to 40 km. We show that the equilibrium temperature and time are sensitive to the modifications in the collision frequencies and ionization rate based on the updated electron interaction cross sections

  19. An investigation of roof runoff during rain events at the Royal Military College of Canada and potential discharge to Lake Ontario.

    Science.gov (United States)

    Kelly, David G; Weir, Ron D; White, Steven D

    2011-01-01

    The Royal Military College of Canada, located on the north eastern shore of Lake Ontario, possesses an abundance of copper roofs and lacks surface water treatment prior to discharge into Lake Ontario. Rainwater, roof runoff and soil samples were collected and analyzed for copper and other parameters. Copper was consistently detected in runoff samples with average concentrations of 3200 +/- 2100 microg/L. Multivariable linear regression analysis for a dependant copper runoff concentration yielded an adjusted R2 value of 0.611, based on an independent variable model using minimum temperature, maximum temperature, total precipitation, and wind speed. Lake water samples taken in the vicinity of storm water outfalls draining areas with copper roofs ranged from 2.0 to 40 microg/L copper. Such data exceed the 2.0 microg/L Canadian Water Quality Guidelines for the Protection of Aquatic Life as outlined by the Canadian Council of Ministers of the Environment (CCME). Analysis of raw, filtered and digested forms suggested that the majority of copper present in runoff and lake water samples was in a dissolved form. The majority of soils taken in this study displayed copper concentrations below the 63 microg/g CCME residential/parkland land use limits. These findings suggested that ion exchange processes between runoff water and soil do not occur to a sufficient extent to elevate copper levels in soil. It may therefore be concluded that the eventual fate of copper, which is not discharged via storm water outfalls, is lost to the water table and Lake Ontario through the sub-soil.

  20. Ultra-violet recombination continuum electron temperature measurements in a non-equilibrium atmospheric argon plasma

    International Nuclear Information System (INIS)

    Gordon, M.H.; Kruger, C.H.

    1991-01-01

    Emission measurements of temperature and electron density have been made downstream of a 50 kW induction plasma torch at temperatures and electron densities ranging between 6000 K and 8500 K and 10 to the 20th and 10 to the 21st/cu cm, respectively. Absolute and relative atomic line intensities, and absolute recombination continuum in both the visible and the UV were separately interpreted in order to characterize a recombining atmospheric argon plasma. Continuum measurements made in the UV at 270 nm were used to directly determine the kinetic electron temperature, independent of a Boltzmann equilibrium, assuming only that the electron velocity distribution is Maxwellian. The data indicate that a nonequilibrium condition exists in which the bound-excited and free electrons are nearly in mutual equilibrium down to the 4P level for electron densities as low as 2 x 10 to the 20th/cu m but that both are overpopulated with respect to the ground state due to finite recombination rates. 13 refs

  1. The kinetics of low-temperature electron-phonon relaxation in a metallic film following instantaneous heating of the electrons

    International Nuclear Information System (INIS)

    Bezuglyi, A.I.; Shklovskii, V.A.

    1997-01-01

    The theoretical analysis of experiments on pulsed laser irradiation of metallic films sputtered on insulating supports is usually based on semiphenomenological dynamical equations for the electron and phonon temperatures, an approach that ignores the nonuniformity and the nonthermal nature of the phonon distribution function. In this paper we discuss a microscopic model that describes the dynamics of the electron-phonon system in terms of kinetic equations for the electron and phonon distribution functions. Such a model provides a microscopic picture of the nonlinear energy relaxation of the electron-phonon system of a rapidly heated film. We find that in a relatively thick film the energy relaxation of electrons consists of three stages: the emission of nonequilibrium phonons by 'hot' electrons, the thermalization of electrons and phonons due to phonon reabsorption, and finally the cooling of the thermalized electron-phonon system as a result of phonon exchange between film and substrate. In thin films, where there is no reabsorption of nonequilibrium phonons, the energy relaxation consists of only one stage, the first. The relaxation dynamics of an experimentally observable quantity, the phonon contribution to the electrical conductivity of the cooling film, is directly related to the dynamics of the electron temperature, which makes it possible to use the data of experiments on the relaxation of voltage across films to establish the electron-phonon and phonon-electron collision times and the average time of phonon escape from film to substrate

  2. Survey of potential electronic applications of high temperature superconductors

    International Nuclear Information System (INIS)

    Hammond, R.B.; Bourne, L.C.

    1991-01-01

    In this paper the authors present a survey of the potential electronic applications of high temperature superconductor (HTSC) thin films. During the past four years there has been substantial speculation on this topic. The authors will cover only a small fraction of the potential electronic applications that have been identified. Their treatment is influenced by the developments over the past few years in materials and device development and in market analysis. They present their view of the most promising potential applications. Superconductors have two important properties that make them attractive for electronic applications. These are (a) low surface resistance at high frequencies, and (b) the Josephson effect

  3. Development of Ultra Low-Temperature Electronics for the AEgIS Experiment

    CERN Document Server

    Kaltenbacher, Thomas; Kellerbauer, Alban; Doser, Michael; Caspers, Friedhelm

    This thesis presents the development of electronics for operation at cryogenic temperatures, with particular emphasis on the cryogenic electronics required for the Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) experiment at the European Organisation for Nuclear Research (CERN). The research is focused on a highly sensitive charged particle detection system for a Penning trap, on cryogenic low-pass filters and on a low-loss DC-contact RF switch. The detection system consists of a high quality factor tuned circuit including a superconducting coil, and a low-noise amplifier. Since the experimental setup of the AEgIS experiment requires it, the developed electronics must reliably operate at 4.2 K (~269C) and in high constant magnetic field of more than 1 Tesla. Therefore, the performance of the cryogenic electronic designs were carefully evaluated at low-temperature/high magnetic field, the result of which have important implications for the AEgIS experiment. Moreover, a new possibility of ...

  4. Temporal evolutions of electron temperature and density with edge localized mode in the JT-60U divertor plasma

    International Nuclear Information System (INIS)

    Nakano, T; Kubo, H; Asakura, N

    2010-01-01

    From the intensity ratios of the three He I lines measured at 20 kHz, the temporal evolutions of the electron temperature and density during and after the power and the particle flow into the divertor plasma caused by edge localized modes are determined. The electron temperature increases from 70 eV to 80 eV with increasing D α intensity. Then, at the peak of D α intensity, the electron temperature starts decreasing down to 60 eV. The electron density increases from 0.1 x 10 19 m -3 to 0.3 x 10 19 m -3 with increasing D α intensity, and then starts to decrease more gradually compared with the electron temperature after the peak of D α intensity. It is interpreted that the increase of the electron temperature is ascribed to the power and the particle flow into the divertor plasma, and that the decrease of the electron temperature and the increase of the electron density are ascribed to the ionization of the recycled neutrals, which consumes the electron energy and produces electrons.

  5. Specifics of surface runoff contents and treatment in large cities

    OpenAIRE

    V.N. Chechevichkin; N.I. Vatin

    2014-01-01

    The degree of surface runoff pollution in large cities has been assessed in modern conditions in the case study of production sites of St. Petersburg. Increased content of petroleum derivatives and heavy metal ions both in rainwater runoff and especially in snowmelt runoff has been revealed. It has been established that the composition of infiltration runoff from the newly built-up sites within the city limits commonly depends on their background, especially in the places of former unaut...

  6. [Regulation effect of forest vegetation on watershed runoff in the Loess Plateau].

    Science.gov (United States)

    Huang, Mingbin; Liu, Xianzhao

    2002-09-01

    The runoff and rainfall data of typical forested and non-forested watersheds in Ziwuling region, which is located in the hinterland of the Loess Plateau, were used to analyze their annual runoff variation comparatively. The result showed that the annual distribution of runoff in forested watersheds was uniform, compared with that in non-forested watersheds. The total runoff in flood season decreased by 8.88 mm and 7.1 mm. Regression analyses between runoff in dried-up season and rainfall in flood season or in dried-up season showed that the rainfall in flood season in forested watersheds could be changed into underground runoff by forest vegetation, and increased the runoff in dried-up season. The annual variation of runoff also indicated that the total effect of forest vegetation on dried-up runoff complement from October to December was 1.69 mm and 0.5 mm, and that from January to May was not significant.

  7. A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models

    Science.gov (United States)

    Gosling, S. N.; Taylor, R. G.; Arnell, N. W.; Todd, M. C.

    2011-01-01

    We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM) and catchment-scale hydrological models (CHM). Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard (Canada), Mekong (SE Asia), Okavango (SW Africa), Rio Grande (Brazil), Xiangxi (China) and Harper's Brook (UK). A single GHM (Mac-PDM.09) is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs include SLURP v. 12.2 (Liard), SLURP v. 12.7 (Mekong), Pitman (Okavango), MGB-IPH (Rio Grande), AV-SWAT-X 2005 (Xiangxi) and Cat-PDM (Harper's Brook). The CHMs typically simulate water resource impacts based on a more explicit representation of catchment water resources than that available from the GHM and the CHMs include river routing, whereas the GHM does not. Simulations of mean annual runoff, mean monthly runoff and high (Q5) and low (Q95) monthly runoff under baseline (1961-1990) and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1) prescribed increases in global-mean air temperature of 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 °C relative to baseline from the UKMO HadCM3 Global Climate Model (GCM) to explore response to different amounts of climate forcing, and (2) a prescribed increase in global-mean air temperature of 2.0 °C relative to baseline for seven GCMs to explore response to climate model structural uncertainty. We find that the differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM (e.g. an absolute GHM-CHM difference in mean annual runoff percentage change for UKMO HadCM3 2 °C warming of up to 25%), and they are generally larger for indicators of high and low monthly runoff. However

  8. A comparative analysis of projected impacts of climate change on river runoff from global and catchment-scale hydrological models

    Directory of Open Access Journals (Sweden)

    S. N. Gosling

    2011-01-01

    Full Text Available We present a comparative analysis of projected impacts of climate change on river runoff from two types of distributed hydrological model, a global hydrological model (GHM and catchment-scale hydrological models (CHM. Analyses are conducted for six catchments that are global in coverage and feature strong contrasts in spatial scale as well as climatic and developmental conditions. These include the Liard (Canada, Mekong (SE Asia, Okavango (SW Africa, Rio Grande (Brazil, Xiangxi (China and Harper's Brook (UK. A single GHM (Mac-PDM.09 is applied to all catchments whilst different CHMs are applied for each catchment. The CHMs include SLURP v. 12.2 (Liard, SLURP v. 12.7 (Mekong, Pitman (Okavango, MGB-IPH (Rio Grande, AV-SWAT-X 2005 (Xiangxi and Cat-PDM (Harper's Brook. The CHMs typically simulate water resource impacts based on a more explicit representation of catchment water resources than that available from the GHM and the CHMs include river routing, whereas the GHM does not. Simulations of mean annual runoff, mean monthly runoff and high (Q5 and low (Q95 monthly runoff under baseline (1961–1990 and climate change scenarios are presented. We compare the simulated runoff response of each hydrological model to (1 prescribed increases in global-mean air temperature of 1.0, 2.0, 3.0, 4.0, 5.0 and 6.0 °C relative to baseline from the UKMO HadCM3 Global Climate Model (GCM to explore response to different amounts of climate forcing, and (2 a prescribed increase in global-mean air temperature of 2.0 °C relative to baseline for seven GCMs to explore response to climate model structural uncertainty.

    We find that the differences in projected changes of mean annual runoff between the two types of hydrological model can be substantial for a given GCM (e.g. an absolute GHM-CHM difference in mean annual runoff percentage change for UKMO HadCM3 2 °C warming of up to 25%, and they are generally larger for indicators of high and low monthly runoff

  9. Runoff, sediment transport, and landform modifications near Sheffield, Illinois

    International Nuclear Information System (INIS)

    Gray, J.R.; deVries, M.P.

    1984-01-01

    Relations among precipitation, runoff, sediment transport, and landform modifications are being evaluated at an 8.1-hectare, low-level radioactive waste disposal site near Sheffield, IL. Rainfall, runoff, and sediment discharge are measured in three basins comprising two-thirds of the site area and in a 1.10-hectare basin in undisturbed terrain 0.5 kilometer south of the site. The effects of slope, land use, and the physical characteristics of surficial material on runoff and sediment transport are evaluated at four 0.001-hectare plots - two on site and two on the undisturbed watershed. Preliminary results indicate that 890 millimeters of precipitation from July 1, 1982, through June 30, 1983, produced 230 millimeters of runoff from the site, compared to 50 millimeters of runoff from the undisturbed basin. Storm-sediment yields from the site consistently exceed yields from the undisturbed area. Runoff and sediment yields from burial-trench covers are consistently lower than yields from the site. Over 110 collapse holes were documented at the site from December 1978 through December 1982. More than 70% of these collapses formed along the periphery of trenches

  10. Runoff, sediment transport, and landform modifications near Sheffield, Illinois

    International Nuclear Information System (INIS)

    Gray, J.R.

    1984-01-01

    Relations among runoff, sediment transport, landform modifications, and precipitation are being evaluated at a 20-acre, low-level radioactive-waste disposal site near Sheffield, Ill. Rainfall, runoff, and sediment discharge are measured in three basins comprising two-thirds of the site area and in a 3.5-acre basin in undisturbed terrain 0.3 mile south of the site. The effects of slope, land use, and the physical characteristics of surficial material on runoff and sediment transport are evaluated at four 110-square-foot plots - two on site and two on the undisturbed basin. Preliminary results indicate the mean annual precipitation of 35 in. from July 1, 1982, through June 30, 1984, produced a mean of 8 in. of runoff annually from the site, compared to less than 2 in. of runoff annually from the undisturbed basin. Storm-sediment yields from the site consistently exceed yields from the undisturbed basin. Runoff and sediment yields from burial-trench covers are consistently lower than yields from the site. Two hundred and forty-four collapse holes were documented at the site from November 7, 1978, through June 7, 1984. More than 70% of these collapses formed along the periphery of trenches

  11. Electron-trapping probability in natural dosemeters as a function of irradiation temperature

    DEFF Research Database (Denmark)

    Wallinga, J.; Murray, A.S.; Wintle, A.G.

    2002-01-01

    The electron-trapping probability in OSL traps as a function of irradiation temperature is investigated for sedimentary quartz and feldspar. A dependency was found for both minerals; this phenomenon could give rise to errors in dose estimation when the irradiation temperature used in laboratory...... procedures is different from that in the natural environment. No evidence was found for the existence of shallow trap saturation effects that Could give rise to a dose-rate dependency of electron trapping....

  12. [Hydrology and pollution characteristics of urban runoff: Beijing as a sample].

    Science.gov (United States)

    Dong, Xin; Du, Peng-Fei; Li, Zhi-Yi; Yu, Zheng-Rong; Wang, Rui; Huang, Jin-Liang

    2008-03-01

    The purpose of this study is identification and characterization of hydrological process of urban runoff, as well as concentration variation of pollutants in it. Samples were collected in 4 rainfall events in Beijing from Jun. 2006 to Aug. 2006. Hydrology and pollution of the rainfall-runoff process were analyzed on roof and road. Study results show that the shapes of hydrological curves of runoff, despite for a 5 - 20 min delay and a milder tendency, are similar to rainfall curves. Runoff coefficients of roof are 0.80 - 0.98, while 0.87 - 0.97 of road. Event mean concentrations (EMC) of pollutants are influenced by build-up and wash-off features, which leads to a higher concentration in road runoff than in roof runoff. Major pollutants that excess the water quality standards are COD, TN, and TP. Evident correlations (> 0.1) are found between pollutants. Correlation with particles are higher for COD and SO4(2-) (> 0.5), while lower for nutrients (pollutant variety, types of land covers, and rainfall intensity. FFE are found more intense in SS, more frequently in road runoff, and more difficult to form for COD and nutrients with low rainfall intensity. Therefore, control of first period of runoff would be an effective approach for runoff management in Beijing.

  13. Temperature and energy effects on secondary electron emission from SiC ceramics induced by Xe17+ ions.

    Science.gov (United States)

    Zeng, Lixia; Zhou, Xianming; Cheng, Rui; Wang, Xing; Ren, Jieru; Lei, Yu; Ma, Lidong; Zhao, Yongtao; Zhang, Xiaoan; Xu, Zhongfeng

    2017-07-25

    Secondary electron emission yield from the surface of SiC ceramics induced by Xe 17+ ions has been measured as a function of target temperature and incident energy. In the temperature range of 463-659 K, the total yield gradually decreases with increasing target temperature. The decrease is about 57% for 3.2 MeV Xe 17+ impact, and about 62% for 4.0 MeV Xe 17+ impact, which is much larger than the decrease observed previously for ion impact at low charged states. The yield dependence on the temperature is discussed in terms of work function, because both kinetic electron emission and potential electron emission are influenced by work function. In addition, our experimental data show that the total electron yield gradually increases with the kinetic energy of projectile, when the target is at a constant temperature higher than room temperature. This result can be explained by electronic stopping power which plays an important role in kinetic electron emission.

  14. Pesticide leaching by agricultural drainage in sloping, mid-textured soil conditions - the role of runoff components.

    Science.gov (United States)

    Zajíček, Antonín; Fučík, Petr; Kaplická, Markéta; Liška, Marek; Maxová, Jana; Dobiáš, Jakub

    2018-04-01

    Dynamics of pesticides and their metabolites in drainage waters during baseflow periods and rainfall-runoff events (RREs) were studied from 2014 to 2016 at three small, tile-drained agricultural catchments in Bohemian-Moravian Highlands, Czech Republic. Drainage systems in this region are typically built in slopes with considerable proportion of drainage runoff originating outside the drained area itself. Continuous monitoring was performed by automated samplers, and the event hydrograph was separated using 18 O and 2 H isotopes and drainage water temperature. Results showed that drainage systems represent a significant source for pesticides leaching from agricultural land. Leaching of pesticide metabolites was mainly associated with baseflow and shallow interflow. Water from causal precipitation diluted their concentrations. The prerequisites for the leaching of parental compounds were a rainfall-runoff event occurring shortly after spraying, and the presence of event water in the runoff. When such situations happened consequently, pesticides concentrations in drainage water were high and the pesticide load reached several grams in a few hours. Presented results introduce new insights into the processes of pesticides movement in small, tile-drained catchments and emphasizes the need to incorporate drainage hydrology and flow-triggered sampling into monitoring programmes in larger catchments as well as in environment-conservation policy.

  15. Calibration of a two-color soft x-ray diagnostic for electron temperature measurement

    Energy Technology Data Exchange (ETDEWEB)

    Reusch, L. M., E-mail: lmmcguire@wisc.edu; Den Hartog, D. J.; Goetz, J.; McGarry, M. B. [University of Wisconsin - Madison, Madison, Wisconsin 53703 (United States); Franz, P. [Consorzio RFX, Padova (Italy); Stephens, H. D. [University of Wisconsin - Madison, Madison, Wisconsin 53703 (United States); Pierce College Fort Steilacoom, Lakewood, Washington 98498 (United States)

    2016-11-15

    The two-color soft x-ray (SXR) tomography diagnostic on the Madison Symmetric Torus is capable of making electron temperature measurements via the double-filter technique; however, there has been a 15% systematic discrepancy between the SXR double-filter (SXR{sub DF}) temperature and Thomson scattering (TS) temperature. Here we discuss calibration of the Be filters used in the SXR{sub DF} measurement using empirical measurements of the transmission function versus energy at the BESSY II electron storage ring, electron microprobe analysis of filter contaminants, and measurement of the effective density. The calibration does not account for the TS and SXR{sub DF} discrepancy, and evidence from experiments indicates that this discrepancy is due to physics missing from the SXR{sub DF} analysis rather than instrumentation effects.

  16. Volumetric runoff coefficients for experimental rural catchments in the Iberian Peninsula

    Science.gov (United States)

    Taguas, Encarnación V.; Molina, Cecilio; Nadal-Romero, Estela; Ayuso, José L.; Casalí, Javier; Cid, Patricio; Dafonte, Jorge; Duarte, Antonio C.; Farguell, Joaquim; Giménez, Rafael; Giráldez, Juan V.; Gómez, Helena; Gómez, Jose A.; González-Hidalgo, J. Carlos; Keizer, J. Jacob; Lucía, Ana; Mateos, Luciano; Rodríguez-Blanco, M. Luz; Schnabel, Sussane; Serrano-Muela, M. Pilar

    2015-04-01

    Analysis of runoff and peaks therein is essential for designing hydraulic infrastructures and for assessing the hydrological implications of likely scenarios of climate and/or land-use change. Different methods are available to calculate runoff coefficients. For instance, the runoff coefficient of a catchment can be described either as the ratio of total depth of runoff to total depth of rainfall or as the ratio of peak flow to rainfall intensity for the time of concentration (Dhakal et al. 2012). If the first definition is considered, runoff coefficients represent the global effect of different features and states of catchments and its determination requires a suitable analysis according to the objectives pursued (Chow et al., 1988). In this work, rainfall-runoff data and physical attributes from small rural catchments located in the Iberian Peninsula (Portugal and Spain) were examined in order to compare the representative values of runoff coefficients using three different approaches: i) statistical analysis of rainfall-runoff data and their quantiles (Dhakal et al., 2012); ii) probabilistic runoff coefficients from the rank-ordered pairs of observed rainfall-runoff data and their relationships with rainfall depths (Schaake et al., 1967); iii) finally, a multiple linear model based on geomorphological attributes. These catchments exhibit great variety with respect to their natural settings, such as climate, topography and lithology. We present a preliminary analysis of the rainfall-runoff relationships as well as their variability in a complex context such as the Iberian Peninsula where contrasted environmental systems coexist. We also discuss reference parameters representing runoff coefficients commonly included into hydrological models. This study is conceived as the first step to explore further working protocols and modeling gaps in a very susceptible area to the climate change such as the Iberian Peninsula's, where the analysis of runoff coefficients is

  17. CADDIS Volume 2. Sources, Stressors and Responses: Urbanization - Temperature

    Science.gov (United States)

    water temperature changes associated with urbanization, heated surface runoff associated with urbanization, how temperature changes associated with urbanization can affect stream biota, interactive effects of urbanizaiton and climate change.

  18. Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

    Science.gov (United States)

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-01-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing cosntitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control. PMID:23202881

  19. Snowmelt runoff: a new focus of urban nonpoint source pollution.

    Science.gov (United States)

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-11-30

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing constitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control.

  20. Estimating Concentrations of Road-Salt Constituents in Highway-Runoff from Measurements of Specific Conductance

    Science.gov (United States)

    Granato, Gregory E.; Smith, Kirk P.

    1999-01-01

    Discrete or composite samples of highway runoff may not adequately represent in-storm water-quality fluctuations because continuous records of water stage, specific conductance, pH, and temperature of the runoff indicate that these properties fluctuate substantially during a storm. Continuous records of water-quality properties can be used to maximize the information obtained about the stormwater runoff system being studied and can provide the context needed to interpret analyses of water samples. Concentrations of the road-salt constituents calcium, sodium, and chloride in highway runoff were estimated from theoretical and empirical relations between specific conductance and the concentrations of these ions. These relations were examined using the analysis of 233 highwayrunoff samples collected from August 1988 through March 1995 at four highway-drainage monitoring stations along State Route 25 in southeastern Massachusetts. Theoretically, the specific conductance of a water sample is the sum of the individual conductances attributed to each ionic species in solution-the product of the concentrations of each ion in milliequivalents per liter (meq/L) multiplied by the equivalent ionic conductance at infinite dilution-thereby establishing the principle of superposition. Superposition provides an estimate of actual specific conductance that is within measurement error throughout the conductance range of many natural waters, with errors of less than ?5 percent below 1,000 microsiemens per centimeter (?S/cm) and ?10 percent between 1,000 and 4,000 ?S/cm if all major ionic constituents are accounted for. A semi-empirical method (adjusted superposition) was used to adjust for concentration effects-superposition-method prediction errors at high and low concentrations-and to relate measured specific conductance to that calculated using superposition. The adjusted superposition method, which was developed to interpret the State Route 25 highway-runoff records, accounts for

  1. [Research on stormwater runoff quality of mountain city by source area monitoring].

    Science.gov (United States)

    Li, Li-Qing; Shan, Bao-Qing; Zhao, Jian-Wei; Guo, Shu-Gang; Gao, Yong

    2012-10-01

    Stormwater runoff samples were collected from 10 source areas in Mountain City, Chongqing, during five rain events in an attempt to investigate the characteristics of runoff quality and influencing factors. The outcomes are expected to offer practical guidance of sources control of urban runoff pollution. The results indicated that the stormwater runoff of Mountain City presented a strong first flush for almost all events and constituents. The runoff quality indices were also influenced by the rainfall intensity. The concentration of TSS, COD, TN and TP decreased as the rainfall intensity increased. The concentrations of COD and TP in stormwater runoff were highly correlated with TSS concentrations. Suspended solid matter were not only the main pollutant of stormwater runoff but also served as the vehicle for transport of organic matter and phosphorus. Organic matter and phosphorus in stormwatrer runoff were mainly bound to particles, whereas nitrogen was predominantly dissolved, with ammonia and nitrate. A significant difference of stormwater runoff quality was observed among the ten monitored source areas. The highest magnitude of urban stormwater runoff pollution was expected in the commercial area and the first trunk road, followed by the minor road, residential area, parking lot and roof. Urban surface function, traffic volume, population density, and street sweeping practice are the main factors determining spatial differentiation of urban surface runoff quality. Commercial area, the first trunk road and residential area with high population density are the critical sources areas of urban stormwater runoff pollution.

  2. Validation of gyrokinetic simulations with measurements of electron temperature fluctuations and density-temperature phase angles on ASDEX Upgrade

    Science.gov (United States)

    Freethy, S. J.; Görler, T.; Creely, A. J.; Conway, G. D.; Denk, S. S.; Happel, T.; Koenen, C.; Hennequin, P.; White, A. E.; ASDEX Upgrade Team

    2018-05-01

    Measurements of turbulent electron temperature fluctuation amplitudes, δTe ⊥/Te , frequency spectra, and radial correlation lengths, Lr(Te ⊥) , have been performed at ASDEX Upgrade using a newly upgraded Correlation ECE diagnostic in the range of scales k⊥scale non-linear gyrokinetic turbulence simulations of the outer core (ρtor = 0.75) of a low density, electron heated L-mode plasma, performed using the gyrokinetic simulation code, GENE. The ion and electron temperature gradients were scanned within uncertainties. It is found that gyrokinetic simulations are able to match simultaneously the electron and ion heat flux at this radius within the experimental uncertainties. The simulations were performed based on a reference discharge for which δTe ⊥/Te measurements were available, and Lr(Te ⊥) and αnT were then predicted using synthetic diagnostics prior to measurements in a repeat discharge. While temperature fluctuation amplitudes are overestimated by >50% for all simulations within the sensitivity scans performed, good quantitative agreement is found for Lr(Te ⊥) and αnT. A validation metric is used to quantify the level of agreement of individual simulations with experimental measurements, and the best agreement is found close to the experimental gradient values.

  3. Runoff as a factor in USLE/RUSLE technology

    Science.gov (United States)

    Kinnell, Peter

    2014-05-01

    Modelling erosion for prediction purposes started with the development of the Universal Soil Loss Equation the focus of which was the prediction of long term (~20) average annul soil loss from field sized areas. That purpose has been maintained in the subsequent revision RUSLE, the most widely used erosion prediction model in the world. The lack of ability to predict short term soil loss saw the development of so-called process based models like WEPP and EUROSEM which focussed on predicting event erosion but failed to improve the prediction of long term erosion where the RUSLE worked well. One of the features of erosion recognised in the so-called process based modes is the fact that runoff is a primary factor in rainfall erosion and some modifications of USLE/RUSLE model have been proposed have included runoff as in independent factor in determining event erosivity. However, these models have ignored fundamental mathematical rules. The USLE-M which replaces the EI30 index by the product of the runoff ratio and EI30 was developed from the concept that soil loss is the product of runoff and sediment concentration and operates in a way that obeys the mathematical rules upon which the USLE/RUSLE model was based. In accounts for event soil loss better that the EI30 index where runoff values are known or predicted adequately. RUSLE2 now includes a capacity to model runoff driven erosion.

  4. Pollution loads in urban runoff and sanitary wastewater.

    Science.gov (United States)

    Taebi, Amir; Droste, Ronald L

    2004-07-05

    While more attention has been paid in recent years to urban point source pollution control through the establishment of wastewater treatment plants in many developing countries, no considerable planning nor any serious measures have been taken to control urban non-point source pollution (urban stormwater runoff). The present study is a screening analysis to investigate the pollution loads in urban runoff compared to point source loads as a first prerequisite for planning and management of receiving water quality. To compare pollutant loads from point and non-point urban sources, the pollutant load is expressed as the weight of pollutant per hectare area per year (kg/ha.year). Unit loads were estimated in stormwater runoff, raw sanitary wastewater and secondary treatment effluents in Isfahan, Iran. Results indicate that the annual pollution load in urban runoff is lower than the annual pollution load in sanitary wastewater in areas with low precipitation but it is higher in areas with high precipitation. Two options, namely, advanced treatment (in lieu of secondary treatment) of sanitary wastewater and urban runoff quality control systems (such as detention ponds) were investigated as controlling systems for pollution discharges into receiving waters. The results revealed that for Isfahan, as a low precipitation urban area, advanced treatment is a more suitable option, but for high precipitation urban areas, urban surface runoff quality control installations were more effective for suspended solids and oxygen-demanding matter controls, and that advanced treatment is the more effective option for nutrient control.

  5. Pollution loads in urban runoff and sanitary wastewater

    International Nuclear Information System (INIS)

    Taebi, Amir; Droste, Ronald L.

    2004-01-01

    While more attention has been paid in recent years to urban point source pollution control through the establishment of wastewater treatment plants in many developing countries, no considerable planning nor any serious measures have been taken to control urban non-point source pollution (urban stormwater runoff). The present study is a screening analysis to investigate the pollution loads in urban runoff compared to point source loads as a first prerequisite for planning and management of receiving water quality. To compare pollutant loads from point and non-point urban sources, the pollutant load is expressed as the weight of pollutant per hectare area per year (kg/ha·year). Unit loads were estimated in stormwater runoff, raw sanitary wastewater and secondary treatment effluents in Isfahan, Iran. Results indicate that the annual pollution load in urban runoff is lower than the annual pollution load in sanitary wastewater in areas with low precipitation but it is higher in areas with high precipitation. Two options, namely, advanced treatment (in lieu of secondary treatment) of sanitary wastewater and urban runoff quality control systems (such as detention ponds) were investigated as controlling systems for pollution discharges into receiving waters. The results revealed that for Isfahan, as a low precipitation urban area, advanced treatment is a more suitable option, but for high precipitation urban areas, urban surface runoff quality control installations were more effective for suspended solids and oxygen-demanding matter controls, and that advanced treatment is the more effective option for nutrient control

  6. Space Charge Saturated Sheath Regime and Electron Temperature Saturation in Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Staack, D.; Smirnov, A.; Fisch, N.J.

    2005-01-01

    Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel. Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission

  7. Applying Multimodel Ensemble from Regional Climate Models for Improving Runoff Projections on Semiarid Regions of Spain

    Science.gov (United States)

    Garcia Galiano, S. G.; Olmos, P.; Giraldo Osorio, J. D.

    2015-12-01

    In the Mediterranean area, significant changes on temperature and precipitation are expected throughout the century. These trends could exacerbate the existing conditions in regions already vulnerable to climatic variability, reducing the water availability. Improving knowledge about plausible impacts of climate change on water cycle processes at basin scale, is an important step for building adaptive capacity to the impacts in this region, where severe water shortages are expected for the next decades. RCMs ensemble in combination with distributed hydrological models with few parameters, constitutes a valid and robust methodology to increase the reliability of climate and hydrological projections. For reaching this objective, a novel methodology for building Regional Climate Models (RCMs) ensembles of meteorological variables (rainfall an temperatures), was applied. RCMs ensembles are justified for increasing the reliability of climate and hydrological projections. The evaluation of RCMs goodness-of-fit to build the ensemble is based on empirical probability density functions (PDF) extracted from both RCMs dataset and a highly resolution gridded observational dataset, for the time period 1961-1990. The applied method is considering the seasonal and annual variability of the rainfall and temperatures. The RCMs ensembles constitute the input to a distributed hydrological model at basin scale, for assessing the runoff projections. The selected hydrological model is presenting few parameters in order to reduce the uncertainties involved. The study basin corresponds to a head basin of Segura River Basin, located in the South East of Spain. The impacts on runoff and its trend from observational dataset and climate projections, were assessed. Considering the control period 1961-1990, plausible significant decreases in runoff for the time period 2021-2050, were identified.

  8. Time-dependent electron temperature diagnostics for high-power aluminum z-pinch plasmas

    International Nuclear Information System (INIS)

    Sanford, T.W.L.; Nash, T.J.; Mock, R.C.

    1996-08-01

    Time-resolved x-ray pinhole photographs and time-integrated radially-resolved x-ray crystal-spectrometer measurements of azimuthally-symmetric aluminum-wire implosions suggest that the densest phase of the pinch is composed of a hot plasma core surrounded by a cooler plasma halo. The slope of the free-bound x-ray continuum, provides a time-resolved, model-independent diagnostic of the core electron temperature. A simultaneous measurement of the time-resolved K-shell line spectra provides the electron temperature of the spatially averaged plasma. Together, the two diagnostics support a 1-D Radiation-Hydrodynamic model prediction of a plasma whose thermalization on axis produces steep radial gradients in temperature, from temperatures in excess of a kilovolt in the core to below a kilovolt in the surrounding plasma halo

  9. Electron-dislocation interaction at low temperatures. Progress report

    International Nuclear Information System (INIS)

    1978-01-01

    The interaction of mobile dislocations with electrons in copper and copper alloys has shown that dislocation motion in copper, at low temperature, can be treated as an analog of an underdamped oscillator. We have also shown that the viscous drag on mobile dislocations in type II superconductors can be treated as an acoustic attenuation of an elastic wave

  10. Climatic Models Ensemble-based Mid-21st Century Runoff Projections: A Bayesian Framework

    Science.gov (United States)

    Achieng, K. O.; Zhu, J.

    2017-12-01

    There are a number of North American Regional Climate Change Assessment Program (NARCCAP) climatic models that have been used to project surface runoff in the mid-21st century. Statistical model selection techniques are often used to select the model that best fits data. However, model selection techniques often lead to different conclusions. In this study, ten models are averaged in Bayesian paradigm to project runoff. Bayesian Model Averaging (BMA) is used to project and identify effect of model uncertainty on future runoff projections. Baseflow separation - a two-digital filter which is also called Eckhardt filter - is used to separate USGS streamflow (total runoff) into two components: baseflow and surface runoff. We use this surface runoff as the a priori runoff when conducting BMA of runoff simulated from the ten RCM models. The primary objective of this study is to evaluate how well RCM multi-model ensembles simulate surface runoff, in a Bayesian framework. Specifically, we investigate and discuss the following questions: How well do ten RCM models ensemble jointly simulate surface runoff by averaging over all the models using BMA, given a priori surface runoff? What are the effects of model uncertainty on surface runoff simulation?

  11. Time-dependent radiolytic yields at room temperature and temperature-dependent absorption spectra of the solvated electrons in polyols

    International Nuclear Information System (INIS)

    Lin Mingzhang; Mostafavi, M.; Lampre, I.; Muroya, Y.; Katsumura, Y.

    2007-01-01

    The molar extinction coefficients at the absorption maximum of the solvated electron spectrum have been evaluated to be 900, 970, and 1000 mol -1 ·m 2 for 1,2-ethanediol (12ED), 1,2-propanediol (12PD), and 1,3-propanediol (13PD), respectively. These values are two-third or three-fourth of the value usually reported in the published report. Picosecond pulse radiolysis studies have aided in depicting the radiolytic yield of the solvated electron in these solvents as a function of time from picosecond to microsecond. The radiolytic yield in these viscous solvents is found to be strongly different from that of the water solution. The temperature dependent absorption spectra of the solvated electron in 12ED, 12PD, and 13PD have been also investigated. In all the three solvents, the optical spectra shift to the red with increasing temperature. While the shape of the spectra does not change in 13PD, a widening on the blue side of the absorption band is observed in 12ED and 12PD at elevated temperatures. (authors)

  12. State of the art of High Temperature Power Electronics

    OpenAIRE

    Buttay , Cyril; Planson , Dominique; Allard , Bruno; Bergogne , Dominique; Bevilacqua , Pascal; Joubert , Charles; Lazar , Mihai; Martin , Christian; Morel , Hervé; Tournier , Dominique; Raynaud , Christophe

    2009-01-01

    International audience; High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500°C, whereas silicon is limited to 150-200°C. Applications such as transportation or deep oil and gas wells drilling can benefit. A few converters operating above 200°C have been demonstrated, but work is still ongoing to design and build a power system able to operate in...

  13. Electron and ion temperatures: a comparison of ground-based incoherent scatter and AE-C satellite measurements

    International Nuclear Information System (INIS)

    Benson, R.F.; Bauer, P.; Brace, L.H.; Carlson, H.C.; Hagen, J.; Hanson, W.B.; Hoegy, W.R.; Torr, M.R.; Wickwar, V.B.

    1977-01-01

    The Atmosphere Exploere-C satellite (AE-C) is uniquely suited for correlative studies with ground-based stations because its on-board propulsion system enables a desired ground station overflight condition to be maintained for a period of several weeks. It also provides the first low-altitude (below 260 km) comparison of satellite and incoherent scatter electron and ion temperatures. More than 40 comparisons of remote and in situ measurements were made by using data from AE-C and four incoherent scatter stations (Arecibo, Chatanika, Millstone Hill, and St. Santin). The results indicate very good agreement between satellite and ground measurements of the ion temperature, the average satellite retarding potential analyzer temperatures differing from the average incoherent scatter temperatures by -2% at St. Santin, +3% at Millstone Hill, and +2% at Arecibo. The electron temperatures also agree well, the average satellite temperatures exceeding the average incoherent scatter temperatures by 3% at St. Santin, 2% at Arecibo, and 11% at Millstone Hill. Several temperature comparisons were made between AE-C and Chatanika. In spite of the highly variable ionosphere often encountered at this high-latitude location, good agreement was obtained between the in situ and remote measurements of electron and ion temperatures. Longitudinal variations are found to be very important in the comparisons of electron temperature in some locations. The agreement between the electron temperatures is considerably better than that found in some earlier comparisons involving satellities at higher altitudes

  14. First stages of zinc runoff in humid tropical climate

    International Nuclear Information System (INIS)

    Meraz, E.; Veleva, L.; Acosta, M.

    2007-01-01

    Frequently used metals in building application are Zinc and hot dip galvanized steel. The zinc has a relatively good atmospheric resistance, due to its oxidation in air and formation of protective layer. However, some of the zinc corrosion products can be dissolved by pluvial precipitations and water condensed on the metal surface. This process is called metal runoff. In order to estimate el zinc runoff in humid tropical climate, since its firs stages, samples of pure zinc and hot dip galvanized steel have been exposed during 2 years in outdoor atmosphere (rural and urban). The data reveal high annual values of zinc runoff (8,20-12,40±0.30 g/m''2 ano), being this process 80% of total mass loss of corroded zinc. The runoff and corrosion processes are more accelerated for zinc, than that of galvanized steel. The principal factors that control the runoff process are discussed. (Author) 48 refs

  15. Short review of runoff and erosion physically based models

    Directory of Open Access Journals (Sweden)

    Gabrić Ognjen

    2015-01-01

    Full Text Available Processes of runoff and erosion are one of the main research subjects in hydrological science. Based on the field and laboratory measurements, and analogous with development of computational techniques, runoff and erosion models based on equations which describe the physics of the process are also developed. Several models of runoff and erosion which describes entire process of genesis and sediment transport on the catchment are described and compared.

  16. Human impacts on runoff regime of middle and lower Yellow River

    Directory of Open Access Journals (Sweden)

    Yan-fang Sang

    2011-03-01

    Full Text Available In this study, the 54-year (1950 to 2003 monthly runoff series from February, April, August, and November, as well as the annual runoff series, measured at both Huayuankou and Lijin hydrological stations were chosen as representative data, and the continuous wavelet transform (CWT was applied to analyze the impacts of human activities on the runoff regime of the middle and lower Yellow River. A point of change in 1970 was first determined, and the observed series before 1970 were considered natural runoff while those after 1970 were restored according to linear trends. Then, the CWT was applied to both the observed and restored runoff series to reveal their variations at multi-temporal scales, including the five temporal ranges of 1–4, 6–8, 9–12, 16–22, and 22–30 years, and the trend at the temporal scale of 54 years. These analysis results are compared and discussed in detail. In conclusion, because of the impacts of human activities, there have been significant changes in the runoff regime in the middle and lower Yellow River since 1970. The decaying tendency of annual runoff has become more pronounced, and the inner-annual distribution of runoff has changed, but human activities have had little impact on the periodic characteristics of runoff.

  17. A Low-Temperature Electron Microscopy and Electron Diffraction Study of La1.84Sr0.16CuO4

    Science.gov (United States)

    Onozuka, Takashi; Omori, Mamoru; Hirabayashi, Makoto; Syono, Yasuhiko

    1987-10-01

    A high-Tc superconducting compound, La1.84Sr0.16CuO4, has been investigated by electron microscopy and electron diffraction in the range from 10 K to ambient temperature. The tetragonal K2NiF4-type structure undergoes an orthorhombic distortion below about 130 K. In the low-temperature phase, extra diffraction spots and twin lamellae are observed reversibly on cooling and heating in situ. Based on the observed results, a plausible structure model with orthorhombic distortion is proposed.

  18. Oxide-cathode activation and surface temperature calculation of electron cooler

    International Nuclear Information System (INIS)

    Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

    2011-01-01

    The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

  19. Erosivity, surface runoff, and soil erosion estimation using GIS-coupled runoff-erosion model in the Mamuaba catchment, Brazil.

    Science.gov (United States)

    Marques da Silva, Richarde; Guimarães Santos, Celso Augusto; Carneiro de Lima Silva, Valeriano; Pereira e Silva, Leonardo

    2013-11-01

    This study evaluates erosivity, surface runoff generation, and soil erosion rates for Mamuaba catchment, sub-catchment of Gramame River basin (Brazil) by using the ArcView Soil and Water Assessment Tool (AvSWAT) model. Calibration and validation of the model was performed on monthly basis, and it could simulate surface runoff and soil erosion to a good level of accuracy. Daily rainfall data between 1969 and 1989 from six rain gauges were used, and the monthly rainfall erosivity of each station was computed for all the studied years. In order to evaluate the calibration and validation of the model, monthly runoff data between January 1978 and April 1982 from one runoff gauge were used as well. The estimated soil loss rates were also realistic when compared to what can be observed in the field and to results from previous studies around of catchment. The long-term average soil loss was estimated at 9.4 t ha(-1) year(-1); most of the area of the catchment (60%) was predicted to suffer from a low- to moderate-erosion risk (soil erosion was estimated to exceed > 12 t ha(-1) year(-1). Expectedly, estimated soil loss was significantly correlated with measured rainfall and simulated surface runoff. Based on the estimated soil loss rates, the catchment was divided into four priority categories (low, moderate, high and very high) for conservation intervention. The study demonstrates that the AvSWAT model provides a useful tool for soil erosion assessment from catchments and facilitates the planning for a sustainable land management in northeastern Brazil.

  20. The MANAGE database: nutrient load and site characteristic updates and runoff concentration data.

    Science.gov (United States)

    Harmel, Daren; Qian, Song; Reckhow, Ken; Casebolt, Pamela

    2008-01-01

    The "Measured Annual Nutrient loads from AGricultural Environments" (MANAGE) database was developed to be a readily accessible, easily queried database of site characteristic and field-scale nutrient export data. The original version of MANAGE, which drew heavily from an early 1980s compilation of nutrient export data, created an electronic database with nutrient load data and corresponding site characteristics from 40 studies on agricultural (cultivated and pasture/range) land uses. In the current update, N and P load data from 15 additional studies of agricultural runoff were included along with N and P concentration data for all 55 studies. The database now contains 1677 watershed years of data for various agricultural land uses (703 for pasture/rangeland; 333 for corn; 291 for various crop rotations; 177 for wheat/oats; and 4-33 yr for barley, citrus, vegetables, sorghum, soybeans, cotton, fallow, and peanuts). Across all land uses, annual runoff loads averaged 14.2 kg ha(-1) for total N and 2.2 kg ha(-1) for total P. On average, these losses represented 10 to 25% of applied fertilizer N and 4 to 9% of applied fertilizer P. Although such statistics produce interesting generalities across a wide range of land use, management, and climatic conditions, regional crop-specific analyses should be conducted to guide regulatory and programmatic decisions. With this update, MANAGE contains data from a vast majority of published peer-reviewed N and P export studies on homogeneous agricultural land uses in the USA under natural rainfall-runoff conditions and thus provides necessary data for modeling and decision-making related to agricultural runoff. The current version can be downloaded at http://www.ars.usda.gov/spa/manage-nutrient.

  1. Urban Runoff: Getting to the Nonpoint

    OpenAIRE

    Pendall, Rolf

    1994-01-01

    Mandates for water-quality improvement have forced regulators and planners to confront the problem of urban runoff, still an important source of water pollution. This ar­ticle discusses those mandates and how to meet them, and provides examples of ongoing nonpoint water pollution control programs in the San Francisco Bay Area. These examples suggest that cleanup of urban runoff may require more comprehensive regional planning to encourage a de­velopment pattern conducive to pollution control.

  2. Total pollution effect of urban surface runoff.

    Science.gov (United States)

    Luo, Hongbing; Luo, Lin; Huang, Gu; Liu, Ping; Li, Jingxian; Hu, Sheng; Wang, Fuxiang; Xu, Rui; Huang, Xiaoxue

    2009-01-01

    For pollution research with regard to urban surface runoff, most sampling strategies to date have focused on differences in land usage. With single land-use sampling, total surface runoff pollution effect cannot be evaluated unless every land usage spot is monitored. Through a new sampling strategy known as mixed stormwater sampling for a street community at discharge outlet adjacent to river, this study assessed the total urban surface runoff pollution effect caused by a variety of land uses and the pollutants washed off from the rain pipe system in the Futian River watershed in Shenzhen City of China. The water quality monitoring indices were COD (chemical oxygen demand), TSS (total suspend solid), TP (total phosphorus), TN (total nitrogen) and BOD (biochemical oxygen demand). The sums of total pollution loads discharged into the river for the four indices of COD, TSS, TN, and TP over all seven rainfall events were very different. The mathematical model for simulating total pollution loads was established from discharge outlet mixed stormwater sampling of total pollution loads on the basis of four parameters: rainfall intensity, total land area, impervious land area, and pervious land area. In order to treat surface runoff pollution, the values of MFF30 (mass first flush ratio) and FF30 (first 30% of runoff volume) can be considered as split-flow control criteria to obtain more effective and economical design of structural BMPs (best management practices) facilities.

  3. Determination of gas temperature in the plasmatron channel according to the known distribution of electronic temperature

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2013-01-01

    Full Text Available An analytical method to calculate the temperature distribution of heavy particles in the channel of the plasma torch on the known distribution of the electronic temperature has been proposed. The results can be useful for a number of model calculations in determining the most effective conditions of gas blowing through the plasma torch with the purpose of heating the heavy component. This approach allows us to understand full details about the heating of cold gas, inpouring the plasma, and to estimate correctly the distribution of the gas temperature inside the channel.

  4. Transport coefficients in high-temperature ionized air flows with electronic excitation

    Science.gov (United States)

    Istomin, V. A.; Oblapenko, G. P.

    2018-01-01

    Transport coefficients are studied in high-temperature ionized air mixtures using the modified Chapman-Enskog method. The 11-component mixture N2/N2+/N /N+/O2/O2+/O /O+/N O /N O+/e- , taking into account the rotational and vibrational degrees of freedom of molecules and electronic degrees of freedom of both atomic and molecular species, is considered. Using the PAINeT software package, developed by the authors of the paper, in wide temperature range calculations of the thermal conductivity, thermal diffusion, diffusion, and shear viscosity coefficients for an equilibrium ionized air mixture and non-equilibrium flow conditions for mixture compositions, characteristic of those in shock tube experiments and re-entry conditions, are performed. For the equilibrium air case, the computed transport coefficients are compared to those obtained using simplified kinetic theory algorithms. It is shown that neglecting electronic excitation leads to a significant underestimation of the thermal conductivity coefficient at temperatures higher than 25 000 K. For non-equilibrium test cases, it is shown that the thermal diffusion coefficients of neutral species and the self-diffusion coefficients of all species are strongly affected by the mixture composition, while the thermal conductivity coefficient is most strongly influenced by the degree of ionization of the flow. Neglecting electronic excitation causes noticeable underestimation of the thermal conductivity coefficient at temperatures higher than 20 000 K.

  5. Measurements of electron density and temperature profiles in a gas blanket experiment

    International Nuclear Information System (INIS)

    Kuthy, A.

    1979-02-01

    Radial profiles of electron density, temperature and H sub(β) intensity are presented for the rotating plasma device F-1. The hydrogen filling pressure, the average magnetic field strength at the midplane, and the power input to the discharge have been varied in the ranges 10-100 mTorr, 0.25-0.5 Tesla, and 0.1 to 1.5 MW, respectively. These experiments have been performed with the main purpose of studying the gas blanket (cold-mantle) state of the plasma. It is shown, that a simple spectroscopic method can be used to derive the radial distribution of the electron temperature in such plasmas. The observed peak temperatures and densities are in agreement with earlier theoretical estimates. (author)

  6. SPATIAL DISTRIBUTION OF THE AVERAGE RUNOFF IN THE IZA AND VIȘEU WATERSHEDS

    Directory of Open Access Journals (Sweden)

    HORVÁTH CS.

    2015-03-01

    Full Text Available The average runoff represents the main parameter with which one can best evaluate an area’s water resources and it is also an important characteristic in al river runoff research. In this paper we choose a GIS methodology for assessing the spatial evolution of the average runoff, using validity curves we identifies three validity areas in which the runoff changes differently with altitude. The tree curves were charted using the average runoff values of 16 hydrometric stations from the area, eight in the Vișeu and eight in the Iza river catchment. Identifying the appropriate areas of the obtained correlations curves (between specific average runoff and catchments mean altitude allowed the assessment of potential runoff at catchment level and on altitudinal intervals. By integrating the curves functions in to GIS we created an average runoff map for the area; from which one can easily extract runoff data using GIS spatial analyst functions. The study shows that from the three areas the highest runoff corresponds with the third zone but because it’s small area the water volume is also minor. It is also shown that with the use of the created runoff map we can compute relatively quickly correct runoff values for areas without hydrologic control.

  7. Electronic temperature control and measurements reactor fuel rig circuits

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, S W

    1980-01-01

    The electronic circuits of two digital temperature meters developed for the thermocouple of Ni-NiCr type are described. The output thermocouple signal as converted by means of voltage-to-freguency converter. The frequency is measured by a digital scaler controled by quartz generator signals. One of the described meter is coupled with digital temperature controler which drives the power stage of the reactor rig heater. The internal rig temperature is measured by the thermocouple providing the input signal to the mentioned voltage-to-frequency converter, that means the circuits work in the negative feedback loop. The converter frequency-to-voltage ratio is automatically adjusted to match to thermocouple sensitivity changes in the course of the temperature variations. The accuracy of measuring system is of order of +- 1degC for thermocouple temperature changes from 523 K up to 973 K (50degC up to 700degC).

  8. [Characterization and source apportionment of pollutants in urban roadway runoff in Chongqing].

    Science.gov (United States)

    Zhang, Qian-Qian; Wang, Xiao-Ke; Hao, Li-Ling; Hou, Pei-Qiang; Ouyang, Zhi-Yun

    2012-01-01

    By investigating surface runoff from urban roadway in Chongqing, we assessed the characteristics of surface runoff pollution and the effect of rainfall intensity and antecedent dry weather period on water quality. Using multivariate statistical analysis of data of runoff quality, potential pollutants discharged from urban roadway runoff were identified. The results show that the roadway runoff has high levels of COD, TP and TN, the EMC were 60.83-208.03 mg x L(-1), 0.47-1.01 mg x L(-1) and 2.07-5.00 mg x L(-1) respectively, being the main pollutants; The peaks of pollutant concentration are ahead of or synchronous with the peak of runoff volume; the peaks of pollutant concentrations are mostly occurred within 10 minutes of rainfall. The heavy metal concentrations fluctuate dentately during runoff proceeding. Two potential pollution sources to urban roadway runoff apportioned by using principal component analysis are: vehicle's traffic loss and atmospheric dry and wet deposition, and municipal wastes.

  9. Improved rainfall-runoff approach using lumped and conceptual modelling

    OpenAIRE

    Durán Barroso, Pablo

    2016-01-01

    Rainfall-runoff quantification is one of the most important tasks in both engineering and watershed management as it allows to identify, forecast and explain watershed response. The division of the rainfall depth between infiltration and runoff has a high level of complexity due to the spatial heterogeneity in real catchments and the temporal precipitation variability, which provide scale effects on the overall runoff volumes. The Natural Resources Conservation Service Curve Number (NRCS CN) ...

  10. Urban Run-off Volumes Dependency on Rainfall Measurement Method

    DEFF Research Database (Denmark)

    Pedersen, L.; Jensen, N. E.; Rasmussen, Michael R.

    2005-01-01

    Urban run-off is characterized with fast response since the large surface run-off in the catchments responds immediately to variations in the rainfall. Modeling such type of catchments is most often done with the input from very few rain gauges, but the large variation in rainfall over small areas...... resolutions and single gauge rainfall was fed to a MOUSE run-off model. The flow and total volume over the event is evaluated....

  11. Assessing the water balance in the Sahel : Impact of small scale rainfall variability on runoff. Part 2 : Idealized modeling of runoff sensitivity

    OpenAIRE

    Vischel, Théo; Lebel, Thierry

    2007-01-01

    As in many other semi-arid regions in the world, the Sahelian hydrological environment is characterized by a mosaic of small endoreic catchments with dry soil surface conditions producing mostly Hortonian runoff. Using an SCS-type event based rainfall-runoff model, an idealized modeling experiment of a Sahelian environment is set up to study the sensitivity of runoff to small scale rainfall variability. A set of 548 observed rain events is used to force the hydrological model to study the sen...

  12. Pollutant concentrations in road runoff: Southeast Queensland case study

    Energy Technology Data Exchange (ETDEWEB)

    Drapper, D.; Tomlinson, R.; Williams, P.

    2000-04-01

    This paper discusses the results of research into the pollutants in runoff from road pavement surfaces following natural rainfall events. Road runoff water quality was monitored at 21 sites centering around Brisbane, in southeast Queensland, Australia. The sites were selected according to traffic volumes, surrounding land use, pavement surface type, ease of access, and commercial vehicle percentage. Bridge sites were chosen for convenience of sample collection and minimized infrastructure modification. First flush grab samplers were permanently installed at each site to collect the first 20 L of runoff from one of the bridge drainage scuppers. The runoff samples were tested for a number of heavy metals, hydrocarbons, pesticides, and other physical characteristics. The observed results fall within the ranges of concentrations reported internationally and nationally but do not typically follow the 30,000 average annual daily traffic results reported in the United States. Traffic volumes have not been found to be the best indicator of road runoff pollutant concentrations. Interevent duration has been found to be a statistically significant factor for pollutant concentrations. Sites incorporating exit lanes have recorded higher concentrations of acid-extractable copper and zinc, tending to support the hypothesis that brake pad and tire wear caused by rapid deceleration contributes to the concentrations of these metals in road runoff. Laser particle sizing has shown that a significant proportion of the sediment found in the runoff is <100 {micro}m. However, these particulates do settle in water within 24 h, under laboratory conditions. This may be due to the presence of heavy metals.

  13. Hydrologic conditions controlling runoff generation immediately after wildfire

    Science.gov (United States)

    Ebel, Brian A.; Moody, John A.; Martin, Deborah A.

    2012-01-01

    We investigated the control of postwildfire runoff by physical and hydraulic properties of soil, hydrologic states, and an ash layer immediately following wildfire. The field site is within the area burned by the 2010 Fourmile Canyon Fire in Colorado, USA. Physical and hydraulic property characterization included ash thickness, particle size distribution, hydraulic conductivity, and soil water retention curves. Soil water content and matric potential were measured indirectly at several depths below the soil surface to document hydrologic states underneath the ash layer in the unsaturated zone, whereas precipitation and surface runoff were measured directly. Measurements of soil water content showed that almost no water infiltrated below the ash layer into the near-surface soil in the burned site at the storm time scale (i.e., minutes to hours). Runoff generation processes were controlled by and highly sensitive to ash thickness and ash hydraulic properties. The ash layer stored from 97% to 99% of rainfall, which was critical for reducing runoff amounts. The hydrologic response to two rain storms with different rainfall amounts, rainfall intensity, and durations, only ten days apart, indicated that runoff generation was predominantly by the saturation-excess mechanism perched at the ash-soil interface during the first storm and predominantly by the infiltration-excess mechanism at the ash surface during the second storm. Contributing area was not static for the two storms and was 4% (saturation excess) to 68% (infiltration excess) of the catchment area. Our results showed the importance of including hydrologic conditions and hydraulic properties of the ash layer in postwildfire runoff generation models.

  14. Modern (1992–2011) and projected (2012–99) peak snowpack and May–July runoff for the Fort Peck Lake and Lake Sakakawea watersheds in the Upper Missouri River Basin

    Science.gov (United States)

    Stamm, John F.; Todey, Dennis; Mayes Bousted, Barbara; Rossi, Shawn; Norton, Parker A.; Carter, Janet M.

    2016-02-09

    Mountain snowpack is an important contributor to runoff in the Upper Missouri River Basin; for example, high amounts of winter and spring precipitation in the mountains and plains in 2010–11 were associated with the peak runoff of record in 2011 in the Upper Missouri River Basin. To project trends in peak mountain snowpack and runoff in the upcoming decades, multiple linear regression models of peak mountain snowpack and total May–July runoff were developed for the Fort Peck Lake (above Fort Peck Dam) and lower Lake Sakakawea watersheds (between Fort Peck and Garrison Dams) in the Upper Missouri River Basin. Input to regression models included seasonal estimates of precipitation, air temperature, and total reference evapotranspiration stratified by elevation. Calibration was based on records from 107 weather stations from 1991 to 2011. Regressed annual peak mountain snowpack was used as input to the transfer function of May–July runoff. Peak snowpack and May–July runoff were projected for 2012–99 on the basis of air temperature and precipitation from the Community Climate System Model (CCSM) output. Two estimates of projected peak snowpack and May–July runoff for 2012–99 were computed: one estimate was based on output from the CCSM, version 3.0 (CCSM3), and the second estimate was based on output from the CCSM, version 4.0 (CCSM4). The significance of projected trends was based on the Kendall’s tau nonparametric test.

  15. Impact of animal waste application on runoff water quality in field experimental plots.

    Science.gov (United States)

    Hill, Dagne D; Owens, William E; Tchoounwou, Paul B

    2005-08-01

    Animal waste from dairy and poultry operations is an economical and commonly used fertilizer in the state of Louisiana. The application of animal waste to pasture lands not only is a source of fertilizer, but also allows for a convenient method of waste disposal. The disposal of animal wastes on land is a potential nonpoint source of water degradation. Water degradation and human health is a major concern when considering the disposal of large quantities of animal waste. The objective of this research was to determine the effect of animal waste application on biological (fecal coliform, Enterobacter spp. and Escherichia coli) and physical/chemical (temperature, pH, nitrate nitrogen, ammonia nitrogen, phosphate, copper, zinc, and sulfate) characteristics of runoff water in experimental plots. The effects of the application of animal waste have been evaluated by utilizing experimental plots and simulated rainfall events. Samples of runoff water were collected and analyzed for fecal coliforms. Fecal coliforms isolated from these samples were identified to the species level. Chemical analysis was performed following standard test protocols. An analysis of temperature, ammonia nitrogen, nitrate nitrogen, iron, copper, phosphate, potassium, sulfate, zinc and bacterial levels was performed following standard test protocols as presented in Standard Methods for the Examination of Water and Wastewater [1]. In the experimental plots, less time was required in the tilled broiler litter plots for the measured chemicals to decrease below the initial pre-treatment levels. A decrease of over 50% was noted between the first and second rainfall events for sulfate levels. This decrease was seen after only four simulated rainfall events in tilled broiler litter plots whereas broiler litter plots required eight simulated rainfall events to show this same type of reduction. A reverse trend was seen in the broiler litter plots and the tilled broiler plots for potassium. Bacteria numbers

  16. Assessing the benefit of snow data assimilation for runoff modeling in Alpine catchments

    Science.gov (United States)

    Griessinger, Nena; Seibert, Jan; Magnusson, Jan; Jonas, Tobias

    2016-09-01

    In Alpine catchments, snowmelt is often a major contribution to runoff. Therefore, modeling snow processes is important when concerned with flood or drought forecasting, reservoir operation and inland waterway management. In this study, we address the question of how sensitive hydrological models are to the representation of snow cover dynamics and whether the performance of a hydrological model can be enhanced by integrating data from a dedicated external snow monitoring system. As a framework for our tests we have used the hydrological model HBV (Hydrologiska Byråns Vattenbalansavdelning) in the version HBV-light, which has been applied in many hydrological studies and is also in use for operational purposes. While HBV originally follows a temperature-index approach with time-invariant calibrated degree-day factors to represent snowmelt, in this study the HBV model was modified to use snowmelt time series from an external and spatially distributed snow model as model input. The external snow model integrates three-dimensional sequential assimilation of snow monitoring data with a snowmelt model, which is also based on the temperature-index approach but uses a time-variant degree-day factor. The following three variations of this external snow model were applied: (a) the full model with assimilation of observational snow data from a dense monitoring network, (b) the same snow model but with data assimilation switched off and (c) a downgraded version of the same snow model representing snowmelt with a time-invariant degree-day factor. Model runs were conducted for 20 catchments at different elevations within Switzerland for 15 years. Our results show that at low and mid-elevations the performance of the runoff simulations did not vary considerably with the snow model version chosen. At higher elevations, however, best performance in terms of simulated runoff was obtained when using the snowmelt time series from the snow model, which utilized data assimilation

  17. A low-temperature electron microscopy and electron diffraction study of La1.84Sr0.16CuO4

    International Nuclear Information System (INIS)

    Onozuka, Takashi; Omori, Mamoru; Hirabayashi, Makoto; Syono, Yasuhiko

    1987-01-01

    A high-T c superconducting compound, La 1.84 Sr 0.16 CuO 4 , has been investigated by electron microscopy and electron diffraction in the range from 10 K to ambient temperature. The tetragonal K 2 NiF 4 -type structure undergoes an orthorhombic distortion below about 130 K. In the low-temperature phase, extra diffraction spots and twin lamellae are observed reversibly on cooling and heating in situ. Based on the observed results, a plausible structure model with orthorhombic distortion is proposed. (author)

  18. Low latitude electron temperature observed by the CHAMP satellite

    DEFF Research Database (Denmark)

    Stolle, Claudia; Truhlik, V.; Richards, P.

    2012-01-01

    Te morning overshoot (MO). Both, data and model revealed an anti-correlation between the equatorial MO amplitude and solar EUV flux at these altitudes. The CHAMP observations also reveal a post sunset electron temperature anomaly in analogy to the equatorial ionisation anomaly at altitudes below 400...

  19. Electronic structure of the high-temperature oxide superconductors

    International Nuclear Information System (INIS)

    Pickett, W.E.

    1989-01-01

    Since the discovery of superconductivity above 30 K by Bednorz and Mueller in the La copper oxide system, the critical temperature has been raised to 90 K in YBa 2 Cu 3 O 7 and to 110 and 125 K in Bi-based and Tl-based copper oxides, respectively. In the two years since this Nobel-prize-winning discovery, a large number of electronic structure calculations have been carried out as a first step in understanding the electronic properties of these materials. In this paper these calculations (mostly of the density-functional type) are gathered and reviewed, and their results are compared with the relevant experimental data. The picture that emerges is one in which the important electronic states are dominated by the copper d and oxygen p orbitals, with strong hybridization between them. Photon, electron, and positron spectroscopies provide important information about the electronic states, and comparison with electronic structure calculations indicates that, while many features can be interpreted in terms of existing calculations, self-energy corrections (''correlations'') are important for a more detailed understanding. The antiferromagnetism that occurs in some regions of the phase diagram poses a particularly challenging problem for any detailed theory. The study of structural stability, lattice dynamics, and electron-phonon coupling in the copper oxides is also discussed. Finally, a brief review is given of the attempts so far to identify interaction constants appropriate for a model Hamiltonian treatment of many-body interactions in these materials

  20. Run-off from roofing materials

    International Nuclear Information System (INIS)

    Roed, J.

    1985-01-01

    In order to find the runn-off from roof material, a roof has been constructed with two different slopes (30 deg. and 45 deg.). 7 Be and 137 Cs have been used as tracers. Considering new roof material, the pollution removed by run-off processes has been shown to be very different for various roof materials. The pollution is much more easily removed from silicon-treated material than from porous red-tile roof material. Cesium is removed more easily than beryllium. The content of cesium in old roof materials is greater in red-tile than in other less porous roof materials. However, the measured removal from new material does not correspond to the amount accumulated in the old. This could be explained by weathering and by saturation effects. The last effect is probably the more important. The measurements on old material indicate a removal of 44-86% of cesium pollution by run-off, whereas the measurement on new material showed a removal of only 31-50%. It has been demonstrated that the pollution concentration in run-off water could be very different from that in rainwater

  1. Potentialities in electronics of new high critical temperature superconductors

    International Nuclear Information System (INIS)

    Hartemann, P.

    1989-01-01

    The main electronic applications of superconductors involve the signal processing, the electromagnetic wave detection and the magnetometry. Characteristics of devices based on conventional superconductors cooled by liquid helium are given and the changes induced by incorporating high-temperature superconductors are estimated. After a survey of new superconductor properties, the superconducting devices for analog or digital signal processing are reviewed. The gains predicted for high-temperature superconducting analog devices are considered in greater detail. Different sections deal with the infrared or (sub)millimeter wave detection. The most sensitive apparatuses for magnetic measurements are based on SQUIDs. Features of SQUIDs made of granular high-temperature superconducting material samples (grain boundaries behave as barriers of intrinsic junctions) are discussed [fr

  2. Variability of Measured Runoff and Soil Loss from Field Plots

    Directory of Open Access Journals (Sweden)

    F. Asadzadeh

    2016-02-01

    Full Text Available Introduction: Field plots are widely used in studies related to the measurements of soil loss and modeling of erosion processes. Research efforts are needed to investigate factors affecting the data quality of plots. Spatial scale or size of plots is one of these factors which directly affects measuring runoff and soil loss by means of field plots. The effect of plot size on measured runoff or soil loss from natural plots is known as plot scale effect. On the other hand, variability of runoff and sediment yield from replicated filed plots is a main source of uncertainty in measurement of erosion from plots which should be considered in plot data interpretation processes. Therefore, there is a demand for knowledge of soil erosion processes occurring in plots of different sizes and of factors that determine natural variability, as a basis for obtaining soil loss data of good quality. This study was carried out to investigate the combined effects of these two factors by measurement of runoff and soil loss from replicated plots with different sizes. Materials and Methods: In order to evaluate the variability of runoff and soil loss data seven plots, differing in width and length, were constructed in a uniform slope of 9% at three replicates at Koohin Research Station in Qazvin province. The plots were ploughed up to down slope in September 2011. Each plot was isolated using soil beds with a height of 30 cm, to direct generated surface runoff to the lower part of the plots. Runoff collecting systems composed of gutters, pipes and tankswere installed at the end of each plot. During the two-year study period of 2011-2012, plots were maintained in bare conditions and runoff and soil loss were measured for each single event. Precipitation amounts and characteristics were directly measured by an automatic recording tipping-bucket rain gauge located about 200 m from the experimental plots. The entire runoff volume including eroded sediment was measured on

  3. Winter nightime ion temperatures and energetic electrons from 0go 6 plasma measurements

    International Nuclear Information System (INIS)

    Sanatani, S.; Breig, E.L.

    1981-01-01

    This paper presents and discusses ion temperature and suprathermal electron flux data acquired with the retarding potential analyzer on board the ogo 6 satellite when it was in solar eclipse. Attention is directed to measurements in the 400- to 800-km height interval between midnight and predawn in the northern winter nonpolar ionosphere. Statistical analysis of data recorded during a 1-month time span permits a decoupling of horizontal and altitude effects. A distinct longitudinal variation is observed for ion temperature above 500 km, with a significant relative enhancement over the western North Altantic Altitude distributions of ion temperature are compatible with Millstone Hill profiles within the common region of this enhancement. Large fluxes of energetic electrons are observed and extend to mush lower geomagnetic latitudes in the same longitude sector. Both a direct correlation in magnitude and a strong similarity in spatial extent are demonstrated for these ion temperature and electron flux data. The location of the limiting low-altitude boundary for observation of the electron fluxes is variable, dependent on local time and season as well as longitude. Variations in this boundary are found to be consistent with a calculated conjugate solar zenith angle of 99 0 +- 2 0 describing photoproduction of energetic electrons in the southern hemisphere. The ogo 6 data are considered to be indicative of an energy source originating in the sunlit summer hemisphere and providing heat via transport of photoelectrons to a broad but preferential segment of the winter nighttime mid-latitude ionosphere. Ions at other longitudes are without access to this energy source and cool to near the neutral temperature at heights to above 800 km inthe predawn hours

  4. Contaminants in urban runoff to Norwegian fjords

    Energy Technology Data Exchange (ETDEWEB)

    Jartun, Morten [Geological Survey of Norway, Trondheim (Norway); Pettersen, Arne [Norwegian Geotechnical Inst., Oslo (Norway)

    2010-03-15

    Introduction: Sediments from urban stormwater runoff have been collected and analyzed for the content of various contaminants in harbor areas of Harstad, Trondheim, Bergen, and Drammen, Norway. Materials and methods: The concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), tributyltin, heavy metals, and total organic carbon were determined in most samples. This study provides substantial empirical data on the active, ongoing dispersion of pollutants from land-based sources in an urban area toward the marine environments in Norway. Results and discussion: The results of the analyses clearly demonstrate the importance of the urban environment representing a variety of contamination sources, and that stormwater runoff is an important dispersion mechanism of toxic pollutants. Conclusion: The concentrations of different contaminants in the urban runoff sediments show that there are several active pollution sources supplying the runoff systems with PCBs, PAHs (including benzo(a)pyrene, B(a)p), and heavy metals such as lead, mercury, zinc, and cadmium. This study describe the usefulness of the methods on how to examine ongoing urban contamination of harbors and similar recipients before any remediation plan for improving the environmental condition of marine sediments is effectuated. (orig.)

  5. Estimating runoff from ungauged catchments for reservoir water ...

    African Journals Online (AJOL)

    The Lower Middle Zambezi Basin is sandwiched between three hydropower ... This study applied a rainfall-runoff model (HEC-HMS) and GIS techniques to ... Missing data were generated using the mean value infilling method. ... A hydrological model, HEC- HMS, was used to simulate runoff from the ungauged catchments.

  6. Runoff analysis by means of multiple isotope tracers in Iwami river drainage, Akita, Japan

    International Nuclear Information System (INIS)

    Matsubaya, Osamu; Yoshida, Minako; Tanaka-Miyamoto, Kiriko.

    1990-01-01

    By means of three isotope tracer techniques, proportion of direct runoff and characters of groundwater runoff were studied in the Iwami River drainage during a high runoff period for about 3 days, caused by a heavy rainfall of 85 mm for 17 hours. The proportion of direct runoff is 15 % or less of the total runoff caused by the rainfall, while 65 % of river water at the peak of runoff. Differences observed in the runoff manners among 18 O, 2 H, and 3 H are interpreted as a result of preferential runoff of previous precipitations stored in some unsaturated zone above the saturated groundwater zone. Cl - content is not conservative as a tracer to study runoff mechanisms. (author)

  7. Rooftop runoff as a source of contamination: a review.

    Science.gov (United States)

    Lye, Dennis J

    2009-10-15

    Scientific reports concerning chemical and microbiological contaminant levels of rainwater runoff from rooftop collection in both urban and rural areas are reviewed. This alternative source of water has been documented to often contain substantial amounts of contaminants. Studies describing levels of heavy metal contamination specific to runoff from rooftop catchment areas containing exposed metal surfaces are discussed. Depending upon the intended use, scientific evidence is also accumulating that various treatments and disinfections will be required prior to release of roof-runoff water either into surface waters or for more direct consumer usage. For microbial contamination, current proposed standards and guidelines regarding this type of water source are shown to vary widely worldwide. Scientific literature reveals a lack of clarity regarding water quality guidelines and health related standards for certain types of rooftop runoff. Studies suggests that rainwater collection systems which are properly designed, maintained, and treated may provide a valuable supplement to existing water supplies by reducing demand on community water supplies/infrastructure costs, enhancing effective management of storm water runoff, and increasing restoration of underground reservoirs through controlled infiltration.

  8. The Influence of Runoff and Surface Hydrology on Titan's Weather and Climate

    Science.gov (United States)

    Faulk, S.; Lora, J. M.; Mitchell, J.; Moon, S.

    2017-12-01

    Titan's surface liquid distribution has been shown by general circulation models (GCMs) to greatly influence the hydrological cycle, producing characteristic weather and seasonal climate patterns. Simulations from the Titan Atmospheric Model (TAM) with imposed polar methane "wetlands" reservoirs realistically produce observed cloud features and temperature profiles of Titan's atmosphere, whereas "aquaplanet" simulations with a global methane ocean are not as successful. In addition, wetlands simulations, unlike aquaplanet simulations, demonstrate strong correlations between extreme rainfall behavior and observed geomorphic features, indicating the influential role of precipitation in shaping Titan's surface. The wetlands configuration is, in part, motivated by Titan's large-scale topography featuring low-latitude highlands and high-latitude lowlands, with the implication being that methane may concentrate in the high-latitude lowlands by way of runoff and subsurface flow of a global or regional methane table. However, the extent to which topography controls the surface liquid distribution and thus impacts the global hydrological cycle by driving surface and subsurface flow is unclear. Here we present TAM simulations wherein the imposed wetlands reservoirs are replaced by a surface runoff scheme that allows surface liquid to self-consistently redistribute under the influence of topography. We discuss the impact of surface runoff on the surface liquid distribution over seasonal timescales and compare the resulting hydrological cycle to observed cloud and surface features, as well as to the hydrological cycles of the TAM wetlands and aquaplanet simulations. While still idealized, this more realistic representation of Titan's hydrology provides new insight into the complex interaction between Titan's atmosphere and surface, demonstrates the influence of surface runoff on Titan's global climate, and lays the groundwork for further surface hydrology developments in Titan

  9. Heating power at the substrate, electron temperature, and electron density in 2.45 GHz low-pressure microwave plasma

    Science.gov (United States)

    Kais, A.; Lo, J.; Thérèse, L.; Guillot, Ph.

    2018-01-01

    To control the temperature during a plasma treatment, an understanding of the link between the plasma parameters and the fundamental process responsible for the heating is required. In this work, the power supplied by the plasma onto the surface of a glass substrate is measured using the calorimetric method. It has been shown that the powers deposited by ions and electrons, and their recombination at the surface are the main contributions to the heating power. Each contribution is estimated according to the theory commonly used in the literature. Using the corona balance, the Modified Boltzmann Plot (MBP) is employed to determine the electron temperature. A correlation between the power deposited by the plasma and the results of the MBP has been established. This correlation has been used to estimate the electron number density independent of the Langmuir probe in considered conditions.

  10. Extreme heat and runoff extremes in the Swiss Alps

    Directory of Open Access Journals (Sweden)

    M. Zappa

    2007-06-01

    Full Text Available The hydrological response of Swiss river basins to the 2003 European summer heatwave was evaluated by a combined analysis of historical discharge records and specific applications of distributed hydrological modeling. In the summer of 2003, the discharge from headwater streams of the Swiss Central Plateau was only 40%–60% of the long-term average. For alpine basins runoff was about 60%–80% of the average. Glacierized basins showed the opposite behavior. According to the degree of glacierization, the average summer runoff was close or even above average. The hydrological model PREVAH was applied for the period 1982–2005. Even if the model was not calibrated for such extreme meteorological conditions, it was well able to simulate the hydrological responses of three basins. The aridity index φ describes feedbacks between hydrological and meteorological anomalies, and was adopted as an indicator of hydrological drought. The anomalies of φ and temperature in the summer of 2003 exceeded the 1982–2005 mean by more than 2 standard deviations. Catchments without glaciers showed negative correlations between φ and discharge R. In basins with about 15% glacierization, φ and R were not correlated. River basins with higher glacier percentages showed a positive correlation between φ and R. Icemelt was positively correlated with φ and reduced the variability of discharge with larger amounts of meltwater. Runoff generation from the non-glaciated sub-areas was limited by high evapotranspiration and reduced precipitation. The 2003 summer heatwave could be a precursor to similar events in the near future. Hydrological models and further data analysis will allow the identification of the most sensitive regions where heatwaves may become a recurrent natural hazard with large environmental, social and economical impacts.

  11. Measurements of plasma temperature and electron density in laser

    Indian Academy of Sciences (India)

    The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300–2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions.

  12. Madagascar corals reveal a multidecadal signature of rainfall and river runoff since 1708

    Directory of Open Access Journals (Sweden)

    C. A. Grove

    2013-03-01

    Full Text Available Pacific Ocean sea surface temperatures (SST influence rainfall variability on multidecadal and interdecadal timescales in concert with the Pacific Decadal Oscillation (PDO and Interdecadal Pacific Oscillation (IPO. Rainfall variations in locations such as Australia and North America are therefore linked to phase changes in the PDO. Furthermore, studies have suggested teleconnections exist between the western Indian Ocean and Pacific Decadal Variability (PDV, similar to those observed on interannual timescales related to the El Niño Southern Oscillation (ENSO. However, as instrumental records of rainfall are too short and sparse to confidently assess multidecadal climatic teleconnections, here we present four coral climate archives from Madagascar spanning up to the past 300 yr (1708–2008 to assess such decadal variability. Using spectral luminescence scanning to reconstruct past changes in river runoff, we identify significant multidecadal and interdecadal frequencies in the coral records, which before 1900 are coherent with Asian-based PDO reconstructions. This multidecadal relationship with the Asian-based PDO reconstructions points to an unidentified teleconnection mechanism that affects Madagascar rainfall/runoff, most likely triggered by multidecadal changes in North Pacific SST, influencing the Asian Monsoon circulation. In the 20th century we decouple human deforestation effects from rainfall-induced soil erosion by pairing luminescence with coral geochemistry. Positive PDO phases are associated with increased Indian Ocean temperatures and runoff/rainfall in eastern Madagascar, while precipitation in southern Africa and eastern Australia declines. Consequently, the negative PDO phase that started in 1998 may contribute to reduced rainfall over eastern Madagascar and increased precipitation in southern Africa and eastern Australia. We conclude that multidecadal rainfall variability in Madagascar and the western Indian Ocean needs to be

  13. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography

    International Nuclear Information System (INIS)

    Hirsch, J.E.

    2013-01-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. - Highlights: • A new property of superconducting particles is predicted. • Electron holography will show an apparent increase in thickness at low temperatures. • This will result from a predicted increase in the mean inner potential. • This will originate in expulsion of electrons from the interior to the surface. • This is not predicted by the conventional BCS theory of superconductivity

  14. Change detection of runoff-urban growth relationship in urbanised watershed

    International Nuclear Information System (INIS)

    Abas, Aisya Azizah; Hashim, Mazlan

    2014-01-01

    Urban growth has negative environmental impacts that create water-based disasters such as flash floods and storm runoff causing billions of dollars worth of damage each year. Due to serious flash floods in urbanised areas of Malaysia, water resource management is a vital issue. This paper reports on a study that has been carried out using remote sensing techniques and hydrological modelling for examining the spatial patterns changes of urban areas and its impacts on surface runoff. The estimation of surface runoff based on the Soil Conservation Service Curve Number (SCS CN) method was performed by integrating both remote sensing and Geographic Information System (GIS) techniques. Remote sensing is a data sources for monitoring urban growth by quantifying the changes of urban area and its environmental impact are then analysed by using a GIS-based hydrological model. By linking the integrated approach of remote sensing and GIS, the relationship of runoff with urban expansion are further examined. Hence, the changes in runoff due to urbanisation are analysed. This methodology is applied to the central region of Malaysia in Kuala Lumpur, where rapid urban growth has occurred over the last decade. The results showed that there was a significant between spatial patterns of urban growth and estimated runoff depth. The increase in runoff from year 2000, 2006 and 2010 are estimated about five percent

  15. Characterization and Aging Test Methodology for Power Electronic Devices at High Temperature

    International Nuclear Information System (INIS)

    Ibrahim, A.; Khatir, Z.; Dupont, L.

    2011-01-01

    Power electronic modules are key elements in the chain of power conversion. The application areas include aerospace, aviation, railway, electrical distribution, automotive, home automation, oil industry ... But the use of power electronics in high temperature environments is a major strategic issue in the coming years especially in transport. However, the active components based on silicon are limited in their applications and not suitable for those require both high voltages and high ambient temperatures. The materials with wide energy gap like SiC, GaN and diamond, have the advantage of being able to exceed these limits [1,2]. These materials seem adequate to extremely harsh temperature environments and allow the reduction of cooling systems, but also the increasing of switching frequency. (author)

  16. Rapid modification of urban land surface temperature during rainfall

    Science.gov (United States)

    Omidvar, H.; Bou-Zeid, E.; Song, J.; Yang, J.; Arwatz, G.; Wang, Z.; Hultmark, M.; Kaloush, K.

    2017-12-01

    We study the runoff dynamics and heat transfer over urban pavements during rainfall. A kinematic wave approach is combined with heat storage and transfer schemes to develop a model for impervious (with runoff) and pervious (without runoff) pavements. The resulting framework is a numerical prognostic model that can simulate the temperature fields in the subsurface and runoff layers to capture the rapid cooling of the surface, as well as the thermal pollution advected in the runoff. Extensive field measurements were then conducted over experimental pavements in Arizona to probe the physics and better represent the relevant processes in the model, and then to validate the model. The experimental data and the model results were in very good agreements, and their joint analysis elucidated the physics of the rapid heat transfer from the subsurface to the runoff layer. Finally, we apply the developed model to investigate how the various hydrological and thermal properties of the pavements, as well as ambient environmental conditions, modulate the surface and runoff thermal dynamics, what is the relative importance of each of them, and how we can apply the model mitigate the adverse impacts of urbanization.

  17. Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment

    International Nuclear Information System (INIS)

    Boyle, D. P.; Majeski, R.; Schmitt, J. C.; Auburn University, AL; Hansen, C.

    2017-01-01

    It has been predicted for over a decade that low-recycling plasma-facing components in fusion devices would allow high edge temperatures and flat or nearly flat temperature profiles. In recent experiments with lithium wall coatings in the Lithium Tokamak Experiment (LTX), a hot edge (> 200 eV) and flat electron temperature profiles have been measured following the termination of external fueling. In this work, reduced recycling was demonstrated by retention of ~ 60% of the injected hydrogen in the walls following the discharge. Electron energy confinement followed typical Ohmic confinement scaling during fueling, but did not decrease with density after fueling terminated, ultimately exceeding the scaling by ~ 200% . Lastly, achievement of the low-recycling, hot edge regime has been an important goal of LTX and lithium plasma-facing component research in general, as it has potentially significant implications for the operation, design, and cost of fusion devices.

  18. Experimental study on soluble chemical transfer to surface runoff from soil.

    Science.gov (United States)

    Tong, Juxiu; Yang, Jinzhong; Hu, Bill X; Sun, Huaiwei

    2016-10-01

    Prevention of chemical transfer from soil to surface runoff, under condition of irrigation and subsurface drainage, would improve surface water quality. In this paper, a series of laboratory experiments were conducted to assess the effects of various soil and hydraulic factors on chemical transfer from soil to surface runoff. The factors include maximum depth of ponding water on soil surface, initial volumetric water content of soil, depth of soil with low porosity, type or texture of soil and condition of drainage. In the experiments, two soils, sand and loam, mixed with different quantities of soluble KCl were filled in the sandboxes and prepared under different initial saturated conditions. Simulated rainfall induced surface runoff are operated in the soils, and various ponding water depths on soil surface are simulated. Flow rates and KCl concentration of surface runoff are measured during the experiments. The following conclusions are made from the study results: (1) KCl concentration in surface runoff water would decrease with the increase of the maximum depth of ponding water on soil surface; (2) KCl concentration in surface runoff water would increase with the increase of initial volumetric water content in the soil; (3) smaller depth of soil with less porosity or deeper depth of soil with larger porosity leads to less KCl transfer to surface runoff; (4) the soil with finer texture, such as loam, could keep more fertilizer in soil, which will result in more KCl concentration in surface runoff; and (5) good subsurface drainage condition will increase the infiltration and drainage rates during rainfall event and will decrease KCl concentration in surface runoff. Therefore, it is necessary to reuse drained fertile water effectively during rainfall, without polluting groundwater. These study results should be considered in agriculture management to reduce soluble chemical transfer from soil to surface runoff for reducing non-point sources pollution.

  19. Electron temperature anisotropy constraints in the solar wind

    Czech Academy of Sciences Publication Activity Database

    Štverák, Štěpán; Trávníček, Pavel M.; Maksimovic, M.; Marsch, E.; Fazakerley, A.; Scime, E. E.

    2008-01-01

    Roč. 113, A3 /2008/ (2008), A03103/1-A03103/10 ISSN 0148-0227 R&D Projects: GA AV ČR IAA300420602 Grant - others:EU(XE) ESA-PECS project No. 98024 Institutional research plan: CEZ:AV0Z10030501; CEZ:AV0Z30420517 Keywords : solar wind electrons * temperature anisotropy * radial Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.147, year: 2008

  20. Temperature-dependent surface structure, composition, and electronic properties of the clean SrTiO3(111) crystal face: Low-energy-electron diffraction, Auger-electron spectroscopy, electron energy loss, and ultraviolet-photoelectron spectroscopy studies

    International Nuclear Information System (INIS)

    Lo, W.J.; Somorjai, G.A.

    1978-01-01

    Low-energy-electron diffraction, Auger-electron spectroscopy, electron-energy-loss, and ultraviolet-photoelectron spectroscopies were used to study the structure, composition, and electron energy distribution of a clean single-crystal (111) face of strontium titanate (perovskite). The dependence of the surface chemical composition on the temperature has been observed along with corresponding changes in the surface electronic properties. High-temperature Ar-ion bombardment causes an irreversible change in the surface structure, stoichiometry, and electron energy distribution. In contrast to the TiO 2 surface, there are always significant concentrations of Ti 3+ in an annealed ordered SrTiO 3 (111) surface. This stable active Ti 3+ monolayer on top of a substrate with large surface dipole potential makes SrTiO 3 superior to TiO 2 when used as a photoanode in the photoelectrochemical cell

  1. Runoff Calculation by Neural Networks Using Radar Rainfall Data

    OpenAIRE

    岡田, 晋作; 四俵, 正俊

    1997-01-01

    Neural networks, are used to calculate runoff from weather radar data and ground rain gauge data. Compared to usual runoff models, it is easier to use radar data in neural network runoff calculation. Basically you can use the radar data directly, or without transforming them into rainfall, as the input of the neural network. A situation with the difficulty of ground measurement is supposed. To cover the area lacking ground rain gauge, radar data are used. In case that the distribution of grou...

  2. Rainfall and runoff characteristics of Namman Basin in the Kingdom of Saudi Arabia

    International Nuclear Information System (INIS)

    Al-Wagdany, A.S.

    2008-01-01

    Namman basin is an arid mountainous basin located in the western region of Saudi Arabia and has drainage area of about 650 km2. Namman unconfined groundwater aquifer is the source of water to the historic underground galleries known as Ain Zubaidah. The galleries became dry due to the fall of groundwater levels dramatically in the last few decades. The galleries can only be restored only if a proper water resources management is utilized in the basin. The aim of this research is to investigate two major hydrological components, namely rainfall and runoff, which are essential for a proper management of the water resources of the basin. Rainfall and runoff records for ten rain gauge stations and one runoff gauge station are used to investigate major characteristics of rainfall and runoff in Namman basin. Rainfall records are analyzed to derive conclusion about rainfall occurrence, depth duration, temporal distribution and extreme values. The relation between rainfall depth and elevation is also investigated. Runoff records are utilized to investigate seasonal variation of runoff. Values of runoff coefficient for all runoff events are computed and the relation between rainfall and runoff for the basin are discussed. The results show that there are more than 30 rainstorms per year and only about two runoff events are usually observed. The temporal analysis of rainfall and runoff indicates that there are two rainy seasons, one is during fall and winter season and other is during spring seasons while runoff is mainly observed in the winter season and the other is during spring seasons while runoff is mainly observed in the winter season. Values of runoff coefficient were very low with mean value of 0.013, which indicate that most rainfall infiltrate through the alluvial channels of the basin. (author)

  3. Precipitation-runoff relations and water-quality characteristics at edge-of-field stations, Discovery Farms and Pioneer Farm, Wisconsin, 2003-8

    Science.gov (United States)

    Stuntebeck, Todd D.; Komiskey, Matthew J.; Peppler, Marie C.; Owens, David W.; Frame, Dennis R.

    2011-01-01

    between January and the end of June. Event mean concentrations of suspended sediment in runoff during unfrozen-ground periods were significantly higher (p2= 0.92), indicating that the sources of nitrogen and phosphorus in runoff were likely similar. Analysis of runoff, concentration, and yield data on annual, monthly, and seasonal time scales, when combined with precipitation, soil moisture, soil temperature, and on-farm field-activity information, revealed conditions in which runoff was most likely. The analysis also revealed the effects that field conditions and the timing of field-management activities-most notably, manure applications and tillage-had on the quantity and quality of surface runoff from agricultural fields.

  4. Impact of global SST gradients on the Mediterranean runoff changes across the Plio-Pleistocene transition

    Science.gov (United States)

    Colleoni, Florence; Cherchi, Annalisa; Masina, Simona; Brierley, Christopher M.

    2015-06-01

    This work explores the impact of the development of global meridional and zonal sea surface temperature (SST) gradients on the Mediterranean runoff variability during the Plio-Pleistocene transition, about 3 Ma. Results show that total annual mean Pliocene Mediterranean runoff is about 40% larger than during the preindustrial period due to more increased extratropical specific humidity. As a consequence of a weakened and extended Hadley cell, the Pliocene northwest Africa hydrological network produces a discharge 30 times larger than today. Our results support the conclusion that during the Pliocene, the Mediterranean water deficit was reduced relative to today due to a larger river discharge. By means of a stand-alone atmospheric general circulation model, we simulate the separate impact of extratropical and equatorial SST cooling on the Mediterranean runoff. While cooling the equatorial SST does not imply significant changes to the Pliocene Mediterranean hydrological budget, the extratropical SST cooling increases the water deficit due to a decrease in precipitation and runoff. Consequently, river discharge from this area reduces to preindustrial levels. The main teleconnections acting upon the Mediterranean area today, i.e., the North Atlantic Oscillation during winter and the "monsoon-desert" mechanism during summer already have a large influence on the climate of our Pliocene simulations. Finally, our results also suggest that in a climate state significantly warmer than today, changes of the Hadley circulation could potentially lead to increased water resources in northwest Africa.

  5. Low-Temperature Electron Beam-Induced Transformations of Cesium Lead Halide Perovskite Nanocrystals

    Science.gov (United States)

    2017-01-01

    Cesium lead halide perovskite (CsPbX3, with X = Br, Cl, I) nanocrystals have been found to undergo severe modifications under the high-energy electron beam irradiation of a transmission electron microscope (80/200 keV). In particular, in our previous work, together with halogen desorption, Pb2+ ions were found to be reduced to Pb0 and then diffused to form lead nanoparticles at temperatures above −40 °C. Here, we present a detailed irradiation study of CsPbBr3 nanocrystals at temperatures below −40 °C, a range in which the diffusion of Pb0 atoms/clusters is drastically suppressed. Under these conditions, the irradiation instead induces the nucleation of randomly oriented CsBr, CsPb, and PbBr2 crystalline domains. In addition to the Br desorption, which accompanies Pb2+ reduction at all the temperatures, Br is also desorbed from the CsBr and PbBr2 domains at low temperatures, leading to a more pronounced Br loss, thus the final products are mainly composed of Cs and Pb. The overall transformation involves the creation of voids, which coalesce upon further exposure, as demonstrated in both nanosheets and nanocuboids. Our results show that although low temperatures hinder the formation of Pb nanoparticles in CsPbBr3 nanocrystals when irradiated, the nanocrystals are nevertheless unstable. Consequently, we suggest that an optimum combination of temperature range, electron energy, and dose rate needs to be carefully chosen for the characterization of halide perovskite nanocrystals to minimize both the Pb nanoparticle formation and the structural decomposition. PMID:28983524

  6. Trend and concentrations of legacy lead (Pb) in highway runoff

    International Nuclear Information System (INIS)

    Kayhanian, Masoud

    2012-01-01

    This study presents the results of lead (Pb) concentrations from both highway runoff and contaminated soil along 32 and 23 highway sites, respectively. In general, the Pb concentration on topsoil (0–15 cm) along highways was much higher than the Pb concentration in subsurface soil (15–60 cm). The Pb deposited on soil appears to be anthropogenic and a strong correlation was found between the Pb concentration in surface soil and highway runoff in urban areas. The concentration of Pb measured during 1980s from highways runoff throughout the world was up to 11 times higher than the measured values in mid 1990s and 2000s. The current Pb deposited on soil near highways appears to be a mixture of paint, tire weight balance and old leaded gasoline combustion. Overall, the Pb phase-out regulation reduced the Pb deposits in the environment and consequently lowered Pb loading into receiving waters. - Highlights: ► Pb concentrations in highway runoff ranged from 0.5 to 752 mg/L. ► 78% of total lead concentration in highway runoff was in particulate form. ► Pb deposited on highway sites was mostly within 0 to 15 cm of soil column. ► Pb concentration in highway runoff and top soil was strongly correlated. ► Current Pb concentration in highway runoff is up to 11 times lower than late 1980s. - Most Pb deposited on soil near highways is within the top 15 cm. This Pb is the major sources of Pb concentration in highway runoff that has substantially been reduced since lead phase-out era.

  7. Radiation damage relative to transmission electron microscopy of biological specimens at low temperature: a review

    International Nuclear Information System (INIS)

    Glaeser, R.M.; Taylor, K.A.

    1978-01-01

    When biological specimens are irradiated by the electron beam in the electron microscope, the specimen structure is damaged as a result of molecular excitation, ionization, and subsequent chemical reactions. The radiation damage that occurs in the normal process of electron microscopy is known to present severe limitations for imaging high resolution detail in biological specimens. The question of radiation damage at low temperatures has therefore been investigated with the view in mind of reducing somewhat the rate at which damage occurs. The radiation damage protection found for small molecule (anhydrous) organic compounds is generally rather limited or even non-existent. However, large molecule, hydrated materials show as much as a 10-fold reduction at low temperature in the rate at which radiation damage occurs, relative to the damage rate at room temperature. In the case of hydrated specimens, therefore, low temperature electron microscopy offers an important advantage as part of the overall effort required in obtaining high resolution images of complex biological structures. (author)

  8. Electron temperature and pressure at the edge of ASDEX Upgrade plasmas. Estimation via electron cyclotron radiation and investigations on the effect of magnetic perturbations

    International Nuclear Information System (INIS)

    Rathgeber, Sylvia K.

    2013-01-01

    Understanding and control of the plasma edge behaviour are essential for the success of ITER and future fusion plants. This requires the availability of suitable methods for assessing the edge parameters and reliable techniques to handle edge phenomena, e.g. to mitigate 'Edge Localized Modes' (ELMs) - a potentially harmful plasma edge instability. This thesis introduces a new method for the estimation of accurate edge electron temperature profiles by forward modelling of the electron cyclotron radiation transport and demonstrates its successful application to investigate the impact of Magnetic Perturbation (MP) fields used for ELM mitigation on the edge kinetic data. While for ASDEX Upgrade bulk plasmas, straightforward analysis of the measured electron cyclotron intensity spectrum based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin edge region relies on full treatment of the radiation transport considering broadened emission and absorption profiles. This is realized in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different independent and complementary diagnostics. The method reveals that in regimes with improved confinement ('High-confinement modes' (H-modes)) the edge gradient of the electron temperature can be several times higher than that of the radiation temperature. Furthermore, the model is able to reproduce the 'shine-through' peak - the observation of increased radiation temperatures at frequencies with cold resonance outside the confined plasma region. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. The accurate knowledge about the edge profiles and gradients of the electron temperature and - including the

  9. Geometric dependency of Tibetan lakes on glacial runoff

    NARCIS (Netherlands)

    Phan Hien, V.; Lindenbergh, R.C.; Menenti, M.

    2013-01-01

    The Tibetan Plateau is an essential source of water for Southeast Asia. The runoff from its ~34 000 glaciers, which occupy an area of ~50 000 km2, feeds Tibetan lakes and major Asian rivers like the Indus and Brahmaputra. Reported glacial shrinkage likely has an impact on the runoff. Unfortunately,

  10. Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

    Science.gov (United States)

    Wei, Zhang; Simin, Li; Fengbing, Tang

    2013-01-01

    To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%–30.91%, 83.29%–90.51%, and 61.54–68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff. PMID:23935444

  11. Characterization of urban runoff pollution between dissolved and particulate phases.

    Science.gov (United States)

    Wei, Zhang; Simin, Li; Fengbing, Tang

    2013-01-01

    To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%-30.91%, 83.29%-90.51%, and 61.54-68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff.

  12. Electron density and temperature in NIO1 RF source operated in oxygen and argon

    Science.gov (United States)

    Barbisan, M.; Zaniol, B.; Cavenago, M.; Pasqualotto, R.; Serianni, G.; Zanini, M.

    2017-08-01

    The NIO1 experiment, built and operated at Consorzio RFX, hosts an RF negative ion source, from which it is possible to produce a beam of maximum 130 mA in H- ions, accelerated up to 60 kV. For the preliminary tests of the extraction system the source has been operated in oxygen, whose high electronegativity allows to reach useful levels of extracted beam current. The efficiency of negative ions extraction is strongly influenced by the electron density and temperature close to the Plasma Grid, i.e. the grid of the acceleration system which faces the source. To support the tests, these parameters have been measured by means of the Optical Emission Spectroscopy diagnostic. This technique has involved the use of an oxygen-argon mixture to produce the plasma in the source. The intensities of specific Ar I and Ar II lines have been measured along lines of sight close to the Plasma Grid, and have been interpreted with the ADAS package to get the desired information. This work will describe the diagnostic hardware, the analysis method and the measured values of electron density and temperature, as function of the main source parameters (RF power, pressure, bias voltage and magnetic filter field). The main results show that not only electron density but also electron temperature increase with RF power; both decrease with increasing magnetic filter field. Variations of source pressure and plasma grid bias voltage appear to affect only electron temperature and electron density, respectively.

  13. Rainfall-runoff and hydraulic modelling integration in the Blatina River

    International Nuclear Information System (INIS)

    Timko, J.

    2017-01-01

    This paper investigates the use and integration of rainfall-runoff modelling and hydrologic modelling of Blatina river catchment. Characteristics of physical-geographical sphere and its components were created within the model, enhancing the robustness of input data for the mathematical modelling of landscape runoff. Rainfall-runoff model HEC-HMS utilised in this research allows using a wide range of methodologies to determine the movement of water in the riverbed, water losses in the basin, hydraulic and hydrological methods of transformation and base-flow. Loss and transformation of water in the basin were modeled with curve numbers method SCS-CN. The simulated hydrograph was calibrated using rainfall-runoff event from June 2009. The same event was also modelled after the deforestation of the focus area. Using hydraulic model MIKE 21, a flood of focus rainfall-runoff area was simulated under both current real and changed land cover scenarios. (authors)

  14. A glacier runoff extension to the Precipitation Runoff Modeling System

    Science.gov (United States)

    Van Beusekom, Ashley E.; Viger, Roland

    2016-01-01

    A module to simulate glacier runoff, PRMSglacier, was added to PRMS (Precipitation Runoff Modeling System), a distributed-parameter, physical-process hydrological simulation code. The extension does not require extensive on-glacier measurements or computational expense but still relies on physical principles over empirical relations as much as is feasible while maintaining model usability. PRMSglacier is validated on two basins in Alaska, Wolverine, and Gulkana Glacier basin, which have been studied since 1966 and have a substantial amount of data with which to test model performance over a long period of time covering a wide range of climatic and hydrologic conditions. When error in field measurements is considered, the Nash-Sutcliffe efficiencies of streamflow are 0.87 and 0.86, the absolute bias fractions of the winter mass balance simulations are 0.10 and 0.08, and the absolute bias fractions of the summer mass balances are 0.01 and 0.03, all computed over 42 years for the Wolverine and Gulkana Glacier basins, respectively. Without taking into account measurement error, the values are still within the range achieved by the more computationally expensive codes tested over shorter time periods.

  15. Fluctuations of the electron temperature measured by intensity interferometry on the W7-AS stellarator

    International Nuclear Information System (INIS)

    Sattler, S.

    1993-12-01

    Fluctuations of the electron temperature can cause a significant amount of the anomalous electron heat conductivity observed on fusion plasmas, even with relative amplitudes below one per cent. None of the standard diagnostics utilized for measuring the electron temperature in the confinement region of fusion plasmas is provided with sufficient spatial and temporal resolution and the sensitivity for small fluctuation amplitudes. In this work a new diagnostic for the measurement of electron temperature fluctuations in the confinement region of fusion plasmas was developed, built up, tested and successfully applied on the W7-AS Stellarator. Transport relevant fluctuations of the electron temperature can in principle be measured by radiometry of the electron cyclotron emission (ECE), but they might be buried completely in natural fluctuations of the ECE due to the thermal nature of this radiation. Fluctuations with relative amplitudes below one per cent can be measured with a temporal resolution in the μs-range and a spatial resolution of a few cm only with the help of correlation techniques. The intensity interferometry method, developed for radio astronomy, was applied here: two independent but identical radiometers are viewing the same emitting volume along crossed lines of sight. If the angle between the sightlines is chosen above a limiting value, which is determined by the spatial coherence properties of thermal radiation, the thermal noise is uncorrelated while the temperature fluctuations remain correlated. With the help of this technique relative amplitudes below 0.1% are accessible to measurement. (orig.)

  16. Frequency analysis of urban runoff quality in an urbanizing catchment of Shenzhen, China

    Science.gov (United States)

    Qin, Huapeng; Tan, Xiaolong; Fu, Guangtao; Zhang, Yingying; Huang, Yuefei

    2013-07-01

    This paper investigates the frequency distribution of urban runoff quality indicators using a long-term continuous simulation approach and evaluates the impacts of proposed runoff control schemes on runoff quality in an urbanizing catchment in Shenzhen, China. Four different indicators are considered to provide a comprehensive assessment of the potential impacts: total runoff depth, event pollutant load, Event Mean Concentration, and peak concentration during a rainfall event. The results obtained indicate that urban runoff quantity and quality in the catchment have significant variations in rainfall events and a very high rate of non-compliance with surface water quality regulations. Three runoff control schemes with the capacity to intercept an initial runoff depth of 5 mm, 10 mm, and 15 mm are evaluated, respectively, and diminishing marginal benefits are found with increasing interception levels in terms of water quality improvement. The effects of seasonal variation in rainfall events are investigated to provide a better understanding of the performance of the runoff control schemes. The pre-flood season has higher risk of poor water quality than other seasons after runoff control. This study demonstrates that frequency analysis of urban runoff quantity and quality provides a probabilistic evaluation of pollution control measures, and thus helps frame a risk-based decision making for urban runoff quality management in an urbanizing catchment.

  17. EVALUATION OF RAINFALL-RUNOFF MODELS FOR MEDITERRANEAN SUBCATCHMENTS

    Directory of Open Access Journals (Sweden)

    A. Cilek

    2016-06-01

    Full Text Available The development and the application of rainfall-runoff models have been a corner-stone of hydrological research for many decades. The amount of rainfall and its intensity and variability control the generation of runoff and the erosional processes operating at different scales. These interactions can be greatly variable in Mediterranean catchments with marked hydrological fluctuations. The aim of the study was to evaluate the performance of rainfall-runoff model, for rainfall-runoff simulation in a Mediterranean subcatchment. The Pan-European Soil Erosion Risk Assessment (PESERA, a simplified hydrological process-based approach, was used in this study to combine hydrological surface runoff factors. In total 128 input layers derived from data set includes; climate, topography, land use, crop type, planting date, and soil characteristics, are required to run the model. Initial ground cover was estimated from the Landsat ETM data provided by ESA. This hydrological model was evaluated in terms of their performance in Goksu River Watershed, Turkey. It is located at the Central Eastern Mediterranean Basin of Turkey. The area is approximately 2000 km2. The landscape is dominated by bare ground, agricultural and forests. The average annual rainfall is 636.4mm. This study has a significant importance to evaluate different model performances in a complex Mediterranean basin. The results provided comprehensive insight including advantages and limitations of modelling approaches in the Mediterranean environment.

  18. Numerical simulation of transient moisture and temperature distribution in polycarbonate and aluminum electronic enclosures

    DEFF Research Database (Denmark)

    Shojaee Nasirabadi, Parizad; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

    2016-01-01

    The challenge of developing a reliable electronic product requires huge amounts of resources and knowledge. Temperature and thermal features directly affect the life of electronic products. Furthermore, moisture can be damaging for electronic components. Nowadays, computational fluid dynamics (CF...

  19. Climate change impact on the river runoff: regional study for the Central Asian Region

    International Nuclear Information System (INIS)

    Agaitseva, Natalya

    2004-01-01

    increase is expected in evaporation from water surfaces of 15-20%. The most severe and climate conditions in the watershed area were predicted under the CCCM model. According to this model, if CO 2 concentration in the atmosphere is doubled, then the runoffs of the Syrdarya and Amudarya rivers are expected to be reduced by 28 and 40%, respectively. According to GFDL and GISS scenarios, presented.(Author)e experiencethe catchment area would increase by 3-4 o C and average annual precipitation volume by 10-15%. Under these scenarios, one could expect that no significant reduction in the Amudarya and Syrdarya runoff would occur. An air temperature rise of 1-2 o C will intensify the process of ice degradation. In 1957-180 glaciers in the Aral Sea river basins lost 115.5 km 3 Of ice (approximately 104 km 3 of water), which constituted almost 20 per cent of the 1957 ice reserve. By 2000 another 14 per cent of the 1957 reserve were lost. By 2020 glaciers will lose at least another 10 per cent of their initial volume. Calculations of regional climatic scenarios by the year 2030 also indicate persistence of present runoff volumes accompanied by an increase in fluctuations from year. Longer-term assessments are more pessimistic, since, along with increasing evaporation, water resource inputs (snow and glaciers in the mountains) are continuously shrinking. (Author)

  20. Effects of electrons on the solar wind proton temperature anisotropy

    International Nuclear Information System (INIS)

    Michno, M. J.; Lazar, M.; Schlickeiser, R.; Yoon, P. H.

    2014-01-01

    Among the kinetic microinstabilities, the firehose instability is one of the most efficient mechanisms to restrict the unlimited increase of temperature anisotropy in the direction of an ambient magnetic field as predicted by adiabatic expansion of collision-poor solar wind. Indeed, the solar wind proton temperature anisotropy detected near 1 AU shows that it is constrained by the marginal firehose condition. Of the two types of firehose instabilities, namely, parallel and oblique, the literature suggests that the solar wind data conform more closely to the marginal oblique firehose condition. In the present work, however, it is shown that the parallel firehose instability threshold is markedly influenced by the presence of anisotropic electrons, such that under some circumstances, the cumulative effects of both electron and proton anisotropies could describe the observation without considering the oblique firehose mode.

  1. Quantitative analysis on sensitive factors of runoff change in Fenhe watershed based on integration approach

    Science.gov (United States)

    Wang, Deng; Jian, Shengqi; Wu, Zening; Zhang, Zhaoxi; Hu, Caihong

    2018-06-01

    The runoff of the Fenhe River flowed into the Yellow River (RRY) is reducing significantly due to the influence of climate change and human activities. It is generating bad situation of shortage of water resources and led to the deterioration of ecological environment of Shanxi Province. At the same time, the reduction in RRY causes the runoff reduction in Yellow River and exacerbated the water resources shortage of the middle area of the Yellow River. Therefore, it is important to alleviate water shortage and develop the soil and water conservation measurements and regional water policy by analyzing the influence of human activities and climate change on the RRY. The existing study quantified the reduction in amount of RRY which caused by human activities and climate change using statistical methods and watershed hydrological model. The main results of the study were as follow: Using hydrological variation diagnosis system, the variation characteristics of long time series of measured annual runoff were analyzed in Hejin station that is the Fenhe River control station. The results showed that the runoff of Fenhe River run into Yellow River declined year by year, in 1971, fell the most obviously. The impact of LUCC on runoff was calculated using the method of area ratio in the Fenhe River basin. Human activities were major factor in the reduction of RRY than the climate change, contributed 83.09 % of the total reduction in RRY, Groundwater exploitation gave the greatest contribution to the decrease in RRY in the scope of several kinds of human activity (30.09 %), followed by coal mining (26.03 %), climate changed contributed 19.17 % of the total reduction of RRY, and the decrease of precipitation contributed 20.81 %. But the variation of air temperature and wind speed would result in the increase of the amount of RRY.

  2. Temperature Dependent Electron Transport Properties of Gold Nanoparticles and Composites: Scanning Tunneling Spectroscopy Investigations.

    Science.gov (United States)

    Patil, Sumati; Datar, Suwarna; Dharmadhikari, C V

    2018-03-01

    Scanning tunneling spectroscopy (STS) is used for investigating variations in electronic properties of gold nanoparticles (AuNPs) and its composite with urethane-methacrylate comb polymer (UMCP) as function of temperature. Films are prepared by drop casting AuNPs and UMCP in desired manner on silicon substrates. Samples are further analyzed for morphology under scanning electron microscopy (SEM) and atomic force microscopy (AFM). STS measurements performed in temperature range of 33 °C to 142 °C show systematic variation in current versus voltage (I-V) curves, exhibiting semiconducting to metallic transition/Schottky behavior for different samples, depending upon preparation method and as function of temperature. During current versus time (I-t) measurement for AuNPs, random telegraphic noise is observed at room temperature. Random switching of tunneling current between two discrete levels is observed for this sample. Power spectra derived from I-t show 1/f2 dependence. Statistical analysis of fluctuations shows exponential behavior with time width τ ≈ 7 ms. Local density of states (LDOS) plots derived from I-V curves of each sample show systematic shift in valance/conduction band edge towards/away from Fermi level, with respect to increase in temperature. Schottky emission is best fitted electron emission mechanism for all samples over certain range of bias voltage. Schottky plots are used to calculate barrier heights and temperature dependent measurements helped in measuring activation energies for electron transport in all samples.

  3. Perennial grass management impacts on runoff and sediment export from vegetated channels in pulse flow runoff events

    International Nuclear Information System (INIS)

    Wilson, H.M.; Cruse, R.M.; Burras, C.L.

    2011-01-01

    The goal of the United States Congress is to replace 30% of United States petroleum with biofuels by 2030. If this goal will be accomplished, it is estimated that 25-50% of the land enrolled in the Conservation Reserve Program (CRP) have its biomass removed. However, the purpose of many conservation practices enrolled in CRP is to improve or maintain water quality and not to serve as a source of biomass. This study was conducted to determine if biomass removal has an effect on runoff and sediment export from vegetated channels during low intensity storms that occur frequently. In June 2006, 24 channels were created that measured 2 m x 10 m. The treatments of grass species (big bluestem, corn, smooth bromegrass, and switchgrass) and biomass removal (removed, not removed) were applied to the channels in a split-plot arrangement. Three times in 2007 and 3 more times in 2008, a 787 L load of water with suspended sediment was drained on the head and sides of each experimental unit and the entire load of water that ran off was collected, weighed, and sampled for sediment concentration. Biomass removal increased runoff and sediment by an average of 15% over the two years of the study. The channels planted to perennial C4 grasses were most effective at reducing runoff and sediment export, while the corn was consistently the least effective at reducing runoff and sediment export. (author)

  4. Perennial grass management impacts on runoff and sediment export from vegetated channels in pulse flow runoff events

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, H.M. [Department of Agriculture and Natural Resources, University of Minnesota-Crookston, 2900 University Avenue, Crookston, MN 56716 (United States); Cruse, R.M.; Burras, C.L. [Agronomy Department, Iowa State University, Ames, IA 50010-1010 (United States)

    2011-01-15

    The goal of the United States Congress is to replace 30% of United States petroleum with biofuels by 2030. If this goal will be accomplished, it is estimated that 25-50% of the land enrolled in the Conservation Reserve Program (CRP) have its biomass removed. However, the purpose of many conservation practices enrolled in CRP is to improve or maintain water quality and not to serve as a source of biomass. This study was conducted to determine if biomass removal has an effect on runoff and sediment export from vegetated channels during low intensity storms that occur frequently. In June 2006, 24 channels were created that measured 2 m x 10 m. The treatments of grass species (big bluestem, corn, smooth bromegrass, and switchgrass) and biomass removal (removed, not removed) were applied to the channels in a split-plot arrangement. Three times in 2007 and 3 more times in 2008, a 787 L load of water with suspended sediment was drained on the head and sides of each experimental unit and the entire load of water that ran off was collected, weighed, and sampled for sediment concentration. Biomass removal increased runoff and sediment by an average of 15% over the two years of the study. The channels planted to perennial C4 grasses were most effective at reducing runoff and sediment export, while the corn was consistently the least effective at reducing runoff and sediment export. (author)

  5. [Analysis of first flush effect of typical underlying surface runoff in Beijing urban city].

    Science.gov (United States)

    Ren, Yu-Fen; Wang, Xiao-Ke; Ouyang, Zhi-Yun; Hou, Pei-Qiang

    2013-01-01

    Rapid increase of the urban impervious underlying surfaces causes a great increase of urban runoff and the accumulation of pollutants on the roof and road surfaces brings many pollutants into the drainage system with the runoff, and it thus becomes a great threat to the urban water environment. To know the runoff pollution process and to build scientific basis for pollutant control, runoff processes from the roof and road surfaces were monitored and analyzed from 2004 to 2006, and the runoff EMC (Event Mean Concentration) was calculated. It was found that two types of runoff were seriously polluted by COD and TN. The COD and TN of roof runoff exceeded the fifth level of the surface water environmental quality standard (GB 3838-2002) by 3.64 and 4.80 times, respectively, and the COD and TN of road runoff exceeded by 3.73 and 1.07 times, respectively. M (V) curve was used to determine the relation between runoff volume and runoff pollution load. Various degrees of the first flush phenomenon were found for TSS, COD, TN and TP in roof runoff. But this phenomenon occurred only for TSS and TP of the road runoff, and on the whole it was not obvious. Properties of the underlying surfaces, rainfall intensity, and pollutant accumulation are all important factors affecting the roof and road runoff pollutant emission characteristics.

  6. Algorithm Development for Multi-Energy SXR based Electron Temperature Profile Reconstruction

    Science.gov (United States)

    Clayton, D. J.; Tritz, K.; Finkenthal, M.; Kumar, D.; Stutman, D.

    2012-10-01

    New techniques utilizing computational tools such as neural networks and genetic algorithms are being developed to infer plasma electron temperature profiles on fast time scales (> 10 kHz) from multi-energy soft-x-ray (ME-SXR) diagnostics. Traditionally, a two-foil SXR technique, using the ratio of filtered continuum emission measured by two SXR detectors, has been employed on fusion devices as an indirect method of measuring electron temperature. However, these measurements can be susceptible to large errors due to uncertainties in time-evolving impurity density profiles, leading to unreliable temperature measurements. To correct this problem, measurements using ME-SXR diagnostics, which use three or more filtered SXR arrays to distinguish line and continuum emission from various impurities, in conjunction with constraints from spectroscopic diagnostics, can be used to account for unknown or time evolving impurity profiles [K. Tritz et al, Bull. Am. Phys. Soc. Vol. 56, No. 12 (2011), PP9.00067]. On NSTX, ME-SXR diagnostics can be used for fast (10-100 kHz) temperature profile measurements, using a Thomson scattering diagnostic (60 Hz) for periodic normalization. The use of more advanced algorithms, such as neural network processing, can decouple the reconstruction of the temperature profile from spectral modeling.

  7. Runoff Potentiality of a Watershed through SCS and Functional Data Analysis Technique

    Directory of Open Access Journals (Sweden)

    M. I. Adham

    2014-01-01

    Full Text Available Runoff potentiality of a watershed was assessed based on identifying curve number (CN, soil conservation service (SCS, and functional data analysis (FDA techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling.

  8. Runoff Potentiality of a Watershed through SCS and Functional Data Analysis Technique

    Science.gov (United States)

    Adham, M. I.; Shirazi, S. M.; Othman, F.; Rahman, S.; Yusop, Z.; Ismail, Z.

    2014-01-01

    Runoff potentiality of a watershed was assessed based on identifying curve number (CN), soil conservation service (SCS), and functional data analysis (FDA) techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling. PMID:25152911

  9. Modeling of the Monthly Rainfall-Runoff Process Through Regressions

    Directory of Open Access Journals (Sweden)

    Campos-Aranda Daniel Francisco

    2014-10-01

    Full Text Available To solve the problems associated with the assessment of water resources of a river, the modeling of the rainfall-runoff process (RRP allows the deduction of runoff missing data and to extend its record, since generally the information available on precipitation is larger. It also enables the estimation of inputs to reservoirs, when their building led to the suppression of the gauging station. The simplest mathematical model that can be set for the RRP is the linear regression or curve on a monthly basis. Such a model is described in detail and is calibrated with the simultaneous record of monthly rainfall and runoff in Ballesmi hydrometric station, which covers 35 years. Since the runoff of this station has an important contribution from the spring discharge, the record is corrected first by removing that contribution. In order to do this a procedure was developed based either on the monthly average regional runoff coefficients or on nearby and similar watershed; in this case the Tancuilín gauging station was used. Both stations belong to the Partial Hydrologic Region No. 26 (Lower Rio Panuco and are located within the state of San Luis Potosi, México. The study performed indicates that the monthly regression model, due to its conceptual approach, faithfully reproduces monthly average runoff volumes and achieves an excellent approximation in relation to the dispersion, proved by calculation of the means and standard deviations.

  10. Formation of presheath and current-free double layer in a two-electron-temperature plasma

    International Nuclear Information System (INIS)

    Sato, Kunihiro; Miyawaki, Fujio

    1992-02-01

    Development of the steady-state potential in a two-temperature-electron plasma in contact with the wall is investigated analytically. It is shown that if the hot- to cold electron temperature ratio is greater than ten, the potential drop in the presheath, which is allowed to have either a small value characterized by the cold electrons or a large value by the hot electrons, discontinuously changes at a critical value for the hot- to total electron density ratio. It is also found that the monotonically decreasing potential structure which consists of the first presheath, a current-free double layer, the second presheath, and the sheath can be steadily formed in a lower range of the hot- to total electron density ratio around the critical value. The current-free double layer is set up due to existence of the two electron species and cold ions generated by ionization so as to connect two presheath potentials at different levels. (author)

  11. Measurement of surface temperature profiles on liquid uranium metal during electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-11-01

    Surface temperature distributions of liquid uranium in a water-cooled copper crucible during electron beam evaporation were measured. Evaporation surface was imaged by a lens through a band-path filter (650{+-}5 nm) and a double mirror system on a charge coupled device (CCD) camera. The video signals of the recorded image were connected to an image processor and converted to two-dimensional spectral radiance profiles. The surface temperatures were obtained from the spectral radiation intensity ratio of the evaporation surface and a freezing point of uranium and/or a reference light source using Planck`s law of radiation. The maximum temperature exceeded 3000 K and had saturation tendency with increasing electron beam input. The measured surface temperatures agreed with those estimated from deposition rates and data of saturated vapor pressure of uranium. (author)

  12. Runoff Variability in the Scott River (SW Spitsbergen in Summer Seasons 2012–2013 in Comparison with the Period 1986–2009

    Directory of Open Access Journals (Sweden)

    Franczak Łukasz

    2016-09-01

    Full Text Available River runoff variability in the Scott River catchment in the summer seasons 2012 and 2013 has been presented in comparison to the multiannual river runoff in 1986–2009. Both in particular seasons and in the analysed multiannual, high variability of discharge rate was recorded. In the research periods 2012–2013, a total of 11 952 water stages and 20 flow rates were measured in the analysed cross-section for the determination of 83 daylong discharges. The mean multiannual discharge of the Scott River amounted to 0.96 m3·s−1. The value corresponds to a specific runoff of 94.6 dm3·s−1·km2, and the runoff layer 937 mm. The maximum values of daily discharge amounted to 5.07 m3·s−1, and the minimum values to 0.002 m3·s−1. The highest runoff occurs in the second and third decade of July, and in the first and second decade of August. The regime of the river is determined by a group of factors, and particularly meteorological conditions affecting the intensity of ablation, and consequently river runoff volume. We found a significant correlation (0.60 in 2012 and 0.67 in 2013 between the air temperature and the Scott River discharge related to the Scott Glacier ice melt.

  13. The hierarchy of controls on snowmelt-runoff generation over seasonally-frozen hillslopes

    OpenAIRE

    Coles, Anna E.; Appels, Willemijn M.; McConkey, Brian G.; McDonnell, Jeffrey J.

    2016-01-01

    Understanding and modeling snowmelt-runoff generation in seasonally-frozen regions is a major challenge in hydrology. Partly, this is because the controls on hillslope-scale snowmelt-runoff generation are potentially extensive and their hierarchy is poorly understood. Understanding the relative importance of controls (e.g. topography, vegetation, land use, soil characteristics, and precipitation dynamics) on runoff response is necessary for model development, spatial extrapolation, and runoff...

  14. Quantitative explanation of some electron temperature profiles measured in situ in the high latitude ionospheric E-region

    International Nuclear Information System (INIS)

    Schlegel, K.; Oyama, Koh-ichiro; Hirao, Kunio

    1983-01-01

    E region electron temperature profiles obtained with a rocket experiment in the Antarctica are compared to theoretical electron temperatures calculated from a model. The main heat source in this model is the heating of the electron gas by unstable plasma waves. Very good agreement between both temperatures is obtained between 105 and 115 km altitude, where this heating mechanism is effective. The agreement is also good below this altitude range, after a refinement of the data analysis procedure for the measured temperatures. Several important consequences of the good agreement are pointed out. (author)

  15. Sensitivity of Inferred Electron Temperature from X-ray Emission of NIF Cryogenic DT Implosions

    Energy Technology Data Exchange (ETDEWEB)

    Klem, Michael [Univ. of Dallas, Irving, TX (United States)

    2015-05-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory seeks to achieve thermonuclear ignition through inertial confinement fusion. The accurate assessment of the performance of each implosion experiment is a crucial step. Here we report on work to derive a reliable electron temperature for the cryogenic deuteriumtritium implosions completed on the NIF using the xray signal from the Ross filter diagnostic. These Xrays are dominated by bremsstrahlung emission. By fitting the xray signal measured through each of the individual Ross filters, the source bremsstrahlung spectrum can be inferred, and an electron temperature of the implosion hot spot inferred. Currently, each filter is weighted equally in this analysis. We present work quantifying the errors with such a technique and the results from investigating the contribution of each filter to the overall accuracy of the temperature inference. Using this research, we also compare the inferred electron temperature against other measured implosion quantities to develop a more complete understanding of the hotspot physics.

  16. Pan-Arctic distributions of continental runoff in the Arctic Ocean.

    Science.gov (United States)

    Fichot, Cédric G; Kaiser, Karl; Hooker, Stanford B; Amon, Rainer M W; Babin, Marcel; Bélanger, Simon; Walker, Sally A; Benner, Ronald

    2013-01-01

    Continental runoff is a major source of freshwater, nutrients and terrigenous material to the Arctic Ocean. As such, it influences water column stratification, light attenuation, surface heating, gas exchange, biological productivity and carbon sequestration. Increasing river discharge and thawing permafrost suggest that the impacts of continental runoff on these processes are changing. Here, a new optical proxy was developed and implemented with remote sensing to determine the first pan-Arctic distribution of terrigenous dissolved organic matter (tDOM) and continental runoff in the surface Arctic Ocean. Retrospective analyses revealed connections between the routing of North American runoff and the recent freshening of the Canada Basin, and indicated a correspondence between climate-driven changes in river discharge and tDOM inventories in the Kara Sea. By facilitating the real-time, synoptic monitoring of tDOM and freshwater runoff in surface polar waters, this novel approach will help understand the manifestations of climate change in this remote region.

  17. Microscopic Superconductivity and Room Temperature Electronics of High-Tc Cuprates

    International Nuclear Information System (INIS)

    Liu Fusui; Chen Wanfang

    2008-01-01

    This paper points out that the Landau criterion for macroscopic superfluidity of He II is only a criterion for microscopic superfluidity of 4 He, extends the Landau criterion to microscopic superconductivity in fermions (electron and hole) system and system with Cooper pairs without long-range phase coherence. This paper gives another three non-superconductive systems that are of microscopic superconductivity. This paper demonstrates that one application of microscopic superconductivity is to establish room temperature electronics of the high-T c cuprates

  18. Analyse on changes of runoff generation and confluence of the Luohe River

    International Nuclear Information System (INIS)

    Yiming Si; Xiaowei Liu

    2004-01-01

    The change trend of water cycle factors such as rainfall, runoff and flood events etc. in the Luohe River basin are analysed based on hydrological data since 1950s. The analysis shows that rainfall has been decreasing, but not much, while runoff has been decreasing remarkably. Under the same rainfall conditions, runoff and peak discharge have dropped considerably, runoff coefficient has become much smaller, and the frequency of flood occurrence has been decreasing. It is considered that environmental variation caused by human activities accounts for the change, in characteristics of runoff generation and confluence in the basin.(Author)

  19. Modelling surface run-off and trends analysis over India

    Indian Academy of Sciences (India)

    exponential model was developed between the rainfall and the run-off that predicted the run-off with an R2 of ... precipitation and other climate parameters is well documented ...... Sen P K 1968 Estimates of the regression coefficient based.

  20. Treatment conditions for the removal of contaminants from road runoff

    OpenAIRE

    Hallberg, Magnus

    2007-01-01

    The pollutant load in road runoff is related to traffic densities and road maintenance activities. Inurbanised areas treatment of road runoff is common and often considered necessary. The pollutantsare partitioned between the particulate and dissolved matter. However, the contaminantstend to have an affinity to the particulate material. Sedimentation, the predominant treatmentmethod for road runoff uses various types of ponds. Design tools used for stormwater treatmentsystems are based on ext...

  1. Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

    OpenAIRE

    Wei, Zhang; Simin, Li; Fengbing, Tang

    2013-01-01

    To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitr...

  2. Relationship between Organic Carbon Runoff to River and Land Cover

    Science.gov (United States)

    Kim, G. S.; Lee, S. G.; Lim, C. H.; Lee, W.; Yoo, S.; Kim, S. J.; Heo, S.; Lee, W. K.

    2017-12-01

    Carbon is an important unit in understanding the ecosystem and energy circulation. Each ecosystem, land, water, and atmosphere, is interconnected through the exchange of energy and organic carbon. In the rivers, primary producers utilize the organic carbon from the land. Understanding the organic carbon uptake into the river is important for understanding the mechanism of river ecosystems. The main organic carbon source of the river is land. However, it is difficult to observe the amount of organic carbon runoff to the river. Therefore, an indirect method should be used to estimate the amount of organic carbon runoff to the river. The organic carbon inflow is caused by the runoff of organic carbon dissolved in water or the inflow of organic carbon particles by soil loss. Therefore, the hydrological model was used to estimate organic carbon runoff through the flow of water. The land cover correlates with soil respiration, soil loss, and so on, and the organic carbon runoff coefficient will be estimated to the river by land cover. Using the organic carbon concentration from water quality data observed at each point in the river, we estimate the amount of organic carbon released from the land. The reason is that the runoff from the watershed converges into the rivers in the watershed, the watershed simulation is conducted based on the water quality data observation point. This defines a watershed that affects organic carbon observation sites. The flow rate of each watershed is calculated by the SWAT (Soil and Water Assessment Tool), and the total organic carbon runoff is calculated by using flow rate and organic carbon concentration. This is compared with the factors related to the amount of organic carbon such as land cover, soil loss, and soil organic carbon, and spatial analysis is carried out to estimate the organic carbon runoff coefficient per land cover.

  3. Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks

    International Nuclear Information System (INIS)

    Sesnic, S.; Diesso, M.; Hill, K.; Holland, A.; Pohl, F.

    1988-01-01

    Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron temperature, the Be filter thickness, and the electronic parameters of the acquisition system are known. PG 1810,1812 ID 131801CON N X-ray diagnostics TT Profile correction to electron temperature and enhancement factor in soft-x-ray pulse-height-analysis measurements in tokamaks AU S. Sesnic, M. Diesso, K. Hill, and A. Holland LO Princeton University, Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 AU F. Pohl LO Max-Planck Institut fuer Plasmaphysik, 8046-Garching, Federal Republic of Germany SD (Presented on 16 March 1988) AB Because soft-x-ray pulse-height-analysis spectra contain chordal information, the electron temperature and the radiation intensity (enhancement factor) measurements do not represent the local values. The correction factors for the electron temperature and the enhancement factor as a function of the temperature and density profile parameters and the energy are obtained. The spectrum distortion due to pulse pileup effects is also evaluated. A set of curves is given from which the distortion of the spectrum can be obtained if the electron tempe

  4. Method for local temperature measurement in a nanoreactor for in situ high-resolution electron microscopy.

    Science.gov (United States)

    Vendelbo, S B; Kooyman, P J; Creemer, J F; Morana, B; Mele, L; Dona, P; Nelissen, B J; Helveg, S

    2013-10-01

    In situ high-resolution transmission electron microscopy (TEM) of solids under reactive gas conditions can be facilitated by microelectromechanical system devices called nanoreactors. These nanoreactors are windowed cells containing nanoliter volumes of gas at ambient pressures and elevated temperatures. However, due to the high spatial confinement of the reaction environment, traditional methods for measuring process parameters, such as the local temperature, are difficult to apply. To address this issue, we devise an electron energy loss spectroscopy (EELS) method that probes the local temperature of the reaction volume under inspection by the electron beam. The local gas density, as measured using quantitative EELS, is combined with the inherent relation between gas density and temperature, as described by the ideal gas law, to obtain the local temperature. Using this method we determined the temperature gradient in a nanoreactor in situ, while the average, global temperature was monitored by a traditional measurement of the electrical resistivity of the heater. The local gas temperatures had a maximum of 56 °C deviation from the global heater values under the applied conditions. The local temperatures, obtained with the proposed method, are in good agreement with predictions from an analytical model. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Rainfall Runoff Mitigation by Retrofitted Permeable Pavement in an Urban Area

    Directory of Open Access Journals (Sweden)

    Muhammad Shafique

    2018-04-01

    Full Text Available Permeable pavement is an effective low impact development (LID practice that can play an important role in reducing rainfall runoff amount in urban areas. Permeable interlocking concrete pavement (PICP was retrofitted in a tremendously developed area of Seoul, Korea and the data was monitored to evaluate its effect on the hydrology and stormwater quality performance for four months. Rainfall runoff was first absorbed by different layers of the PICP system and then contributed to the sewage system. This not only helps to reduce the runoff volume, but also increase the time of concentration. In this experiment, different real rain events were observed and the field results were investigated to check the effectiveness of the PICP system for controlling the rainfall runoff in Songpa, Korea. From the analysis of data, results showed that the PCIP system was very effective in controlling rainfall runoff. Overall runoff reduction performance from the PCIP was found to be around 30–65% during various storm events. In addition, PICP significantly reduced peak flows in different storm events which is very helpful in reducing the chances of water-logging in an urbanized area. Research results also allow us to sum up that retrofitted PICP is a very effective approach for rainfall runoff management in urban areas.

  6. Adhesion of and to soil in runoff as influenced by polyacrylamide.

    Science.gov (United States)

    Bech, Tina B; Sbodio, Adrian; Jacobsen, Carsten S; Suslow, Trevor

    2014-11-01

    Polyacrylamide (PAM) is used in agriculture to reduce soil erosion and has been reported to reduce turbidity, nutrients, and pollutants in surface runoff water. The objective of this work was to determine the effect of PAM on the concentration of enteric bacteria in surface runoff by comparing four enteric bacteria representing phenotypically different motility and hydrophobicity from three soils. Results demonstrated that bacterial surface runoff was differentially influenced by the PAM treatment. Polyacrylamide treatment increased surface runoff for adhered and planktonic cells from a clay soil; significantly decreased surface runoff of adhered bacteria, while no difference was observed for planktonic bacteria from the sandy loam; and significantly decreased the surface runoff of planktonic cells, while no difference was observed for adhered bacteria from the clay loam. Comparing strains from a final water sample collected after 48 h showed a greater loss of while serovar Poona was almost not detected. Thus, (i) the PAM efficiency in reducing the concentration of enteric bacteria in surface runoff was influenced by soil type and (ii) variation in the loss of enteric bacteria highlights the importance of strain-specific properties that may not be captured with general fecal indicator bacteria. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  7. Controlling competing orders via nonequilibrium acoustic phonons: Emergence of anisotropic effective electronic temperature

    Science.gov (United States)

    Schütt, Michael; Orth, Peter P.; Levchenko, Alex; Fernandes, Rafael M.

    2018-01-01

    Ultrafast perturbations offer a unique tool to manipulate correlated systems due to their ability to promote transient behaviors with no equilibrium counterpart. A widely employed strategy is the excitation of coherent optical phonons, as they can cause significant changes in the electronic structure and interactions on short time scales. One of the issues, however, is the inevitable heating that accompanies these resonant excitations. Here, we explore a promising alternative route: the nonequilibrium excitation of acoustic phonons, which, due to their low excitation energies, generally lead to less heating. We demonstrate that driving acoustic phonons leads to the remarkable phenomenon of a momentum-dependent effective temperature, by which electronic states at different regions of the Fermi surface are subject to distinct local temperatures. Such an anisotropic effective electronic temperature can have a profound effect on the delicate balance between competing ordered states in unconventional superconductors, opening a so far unexplored avenue to control correlated phases.

  8. Compatibility analysis of precipitation and runoff trends over the large Siberian watersheds

    OpenAIRE

    Berezovskaya, Svetlana; Yang, Daqing; Kane, Douglas L.

    2004-01-01

    The consistency of long-term yearly precipitation and runoff trends over the largest Arctic watersheds (Ob, Yenisei and Lena Rivers) is examined. Three gridded precipitation datasets (Climatic Research Unit, University of Delaware, NCEP) are used for comparative analyses with runoff data collected at basin outlets. The results generally demonstrate inconsistency in long-term changes of basin precipitation and runoff. The Yenisei River runoff increases significantly, while precipitation data s...

  9. X-ray Heating and Electron Temperature of Laboratory Photoionized Plasmas

    Science.gov (United States)

    Mancini, Roberto; Lockard, Tom; Mayes, Daniel C.; Loisel, Guillaume; Bailey, James E.; Rochau, Gregory; Abdallah, J.; Golovkin, I.

    2018-06-01

    In separate experiments performed at the Z facility of Sandia National Laboratories two different samples were employed to produce and characterize photoionized plasmas. One was a gas cell filled with neon, and the other was a thin silicon layer coated with plastic. Both samples were driven by the broadband x-ray flux produced at the collapse of a wire array z-pinch implosion. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the charge state distribution, and the electron temperature was extracted from a Li-like ion level population ratio. To interpret the temperature measurement, we performed Boltzmann kinetics and radiation-hydrodynamic simulations. We found that non-equilibrium atomic physics and the coupling of the radiation flux to the atomic level population kinetics play a critical role in modeling the x-ray heating of photoionized plasmas. In spite of being driven by similar x-ray drives, differences of ionization and charged state distributions in the neon and silicon plasmas are reflected in the plasma heating and observed electron temperatures.This work was sponsored in part by DOE Office of Science Grant DE-SC0014451, and the Z Facility Fundamental Science Program of SNL.

  10. Modeling time-dependent toxicity to aquatic organisms from pulsed exposure of PAHs in urban road runoff

    International Nuclear Information System (INIS)

    Zhang Wei; Ye Youbin; Tong Yindong; Ou Langbo; Hu Dan; Wang Xuejun

    2011-01-01

    Understanding of the magnitude of urban runoff toxicity to aquatic organisms is important for effective management of runoff quality. In this paper, the aquatic toxicity of polycyclic aromatic hydrocarbons (PAHs) in urban road runoff was evaluated through a damage assessment model. Mortality probability of the organisms representative in aquatic environment was calculated using the monitored PAHs concentration in road runoff. The result showed that the toxicity of runoff in spring was higher than those in summer. Analysis of the time-dependent toxicity of series of runoff water samples illustrated that the toxicity of runoff water in the final phase of a runoff event may be as high as those in the initial phase. Therefore, the storm runoff treatment systems or strategies designed for capture and treatment of the initial portion of runoff may be inappropriate for control of runoff toxicity. - Research highlights: → Toxicity resulting from realistic exposure patterns of urban runoff is evaluated. → Toxicity of runoff water in the final phase is as high as the initial phase. → Treatment of the initial runoff portion is inappropriate to abate runoff toxicity. - Toxicity to aquatic organisms after sequential pulsed exposure to PAHs in urban road runoff is evaluated.

  11. Raster-based derivation of a flood runoff susceptibility map using the revised runoff curve number (CN) for the Kuantan watershed, Malaysia

    DEFF Research Database (Denmark)

    Akbari, Abolghasem; Samah, Azizan Abu; Daryabor, Farshid

    2016-01-01

    This study aims to develop a methodology for generating a flood runoff susceptibility (FRS) map using a revised curve number (CN) method. The study area is in the Kuantan watershed (KW), Malaysia, which was seriously affected by floods in December 2013 and December 2014. A revised runoff CN map w......, the finding of this research provides a road map for government agencies to effectively implement flood mitigation projects in the study area.......This study aims to develop a methodology for generating a flood runoff susceptibility (FRS) map using a revised curve number (CN) method. The study area is in the Kuantan watershed (KW), Malaysia, which was seriously affected by floods in December 2013 and December 2014. A revised runoff CN map....... Approximately 5% of the study area was identified as a very high-risk zone and 13% as high-risk zone. However, the spatial extent of a high-risk zone in the downstream end and lowland areas of the KW could be considered to be the main cause of flood damage in recent years. From practical point of view...

  12. Modelling monthly runoff generation processes following land use changes: groundwater-surface runoff interactions

    Science.gov (United States)

    Bari, M.; Smettem, K. R. J.

    A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, "Ernies" (control, fully forested) and "Lemon" (54% cleared) are in a zone of mean annual rainfall of 725 mm, while "Salmon" (control, fully forested) and "Wights" (100% cleared) are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall-runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i) an upper zone unsaturated store, (ii) a transient stream zone store, (ii) a lower zone unsaturated store and (iv) a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and predicted

  13. Modelling monthly runoff generation processes following land use changes: groundwater–surface runoff interactions

    Directory of Open Access Journals (Sweden)

    M. Bari

    2004-01-01

    Full Text Available A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall–runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, 'Ernies' (control, fully forested and 'Lemon' (54% cleared are in a zone of mean annual rainfall of 725 mm, while 'Salmon' (control, fully forested and 'Wights' (100% cleared are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall–runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i immediately after clearing due to reduced evapotranspiration, and (ii through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i an upper zone unsaturated store, (ii a transient stream zone store, (ii a lower zone unsaturated store and (iv a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and

  14. Phonon and electron temperature and non-Fourier heat transport in thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, I.; Cimmelli, V.A. [Department of Mathematics, Computer Science and Economics, University of Basilicata, Campus Macchia Romana, Viale dell' Ateneo Lucano 10, 85100 Potenza (Italy); Sellitto, A. [Department of Industrial Engineering, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (Italy)

    2017-04-15

    We present a thermodynamic model of heat conductor which allows for different temperatures of phonons and electrons. This model is applied to calculate the steady-state radial temperature profile in a circular thin layer. The compatibility of the obtained temperature profiles with the second law of thermodynamics is investigated in view of the requirement of positive entropy production and of a nonlocal constitutive equation for the entropy flux.

  15. Increasing runoff and sediment load from the Greenland ice sheet at kangerlussuaq (Sonder Stromfjord) in a 30-year perspective, 1979-2008

    Energy Technology Data Exchange (ETDEWEB)

    Mernild, Sebastian Haugard [Los Alamos National Laboratory; Liston, Glen [COLORADO STATE UNIV.; Hasholt, Bent [UNIV OF COPENGAGEN; Steffen, Konrad [UNIV OF COLORADO; Van Den Broeke, Michiel [UTRECHT UNIV; Mcgrath, Daniel [UNIV OF COLORADO; Yde, Jacob [UNIV OF AARHUS

    2009-01-01

    This observation and modeling study provides insights into runoff and sediment load exiting the Watson River drainage basin, Kangerlussuaq, West Greenland during a 30 year period (1978/79-2007/08) when the climate experienced increasing temperatures and precipitation. The 30-year simulations quantify the terrestrial freshwater and sediment output from part of the Greenland Ice Sheet (GrIS) and the land between the GrIS and the ocean, in the context of global warming and increasing GrIS surface melt. We used a snow-evolution modeling system (SnowModel) to simulate the winter accumulation and summer ablation processes, including runoff and surface mass balance (SMB), of the Greenland ice sheet. Observed sediment concentrations were related to observed runoff, producing a sediment-load time series. To a large extent, the SMB fluctuations could be explained by changes in net precipitation (precipitation minus evaporation and sublimation), with 8 out of 30 years having negative SMB, mainly because of relatively low annual net precipitation. The overall trend in net precipitation and runoff increased significantly, while 5MB increased insignificantly throughout the simulation period, leading to enhanced precipitation of 0.59 km{sup 3} w.eq. (or 60%), runoff of 0.43 km{sup 3} w.eq (or 54%), and SMB of 0.16 km3 w.eq. (or 86%). Runoff rose on average from 0.80 km{sup 3} w.eq. in 1978/79 to 1.23 km{sup 3} w.eq. in 2007/08. The percentage of catchment oudet runoff explained by runoff from the GrIS decreased on average {approx} 10%, indicating that catchment runoff throughout the simulation period was influenced more by precipitation and snowmelt events, and less by runoff from the GrIS. Average variations in the increasing Kangerlussuaq runoff from 1978/79 through 2007/08 seem to follow the overall variations in satellite-derived GrIS surface melt, where 64% of the variations in simulated runoff were explained by regional melt conditions on the GrIS. Throughout the simulation

  16. Hillslope runoff and sediment transport in south east Spain

    Science.gov (United States)

    Bracken (Nee Bull), L. J.; Kirkby, M. J.

    2003-04-01

    Runoff from semi-arid hillslopes in SE Spain is generated very selectively at all scales. Site response at the 1 m2 scale may be described by the dynamics of local infiltration and crusting, defining Hydrologically Similar Surfaces (HYSS), which are strongly associated with soil type and vegetation cover. This study reports the use of several reconnaissance methods to define HYSS consistently. These methods are (1) the use of small sediment traps which disturb the surface minimally,(2) the use of painted lines and (3) the identification of Morphological Zones associated with different levels of runoff and sediment transport. Five monitoring sites were established on hillslope concavities in two semi-arid catchments in South East Spain. Rainfall data were also collected from the nearest gauge established during previous research. Results show that a storm event in the Rambla de Nogalte on the 30th of June of 83.0 mm was responsible for a maximum runoff depth of 12 cm and a maximum hillslope sediment transport of 1886 cm3 m-1. The same storm in the Rambla de Torrealvilla produced 53.4 mm of rainfall on the 1st of July 2002, had a maximum runoff depth of 26 cm and was responsible for a maximum hillslope sediment transport of 2311 cm3 m-1. In general sediment transport rate and sediment travel distance increased with the distance downslope into the hillslope hollow, and these were related to the maximum depth of flow produced over the hillside. Very little sediment movement occurred directly downslope of bushes as was expected. No significant relationships were established between sediment transport and slope angle or vegetation cover. However, sediment transport and depth of runoff varied with lithology, with marl sites producing the most runoff and sediment transport. The site located on red schist was particularly unresponsive to rainfall and did not experience much sediment transport. Initial models for the response of larger areas suggest that runoff is controlled

  17. Impact of Roadway Stormwater Runoff on Microbial Contamination in the Receiving Stream.

    Science.gov (United States)

    Wyckoff, Kristen N; Chen, Si; Steinman, Andrew J; He, Qiang

    2017-09-01

    Stormwater runoff from roadways has increasingly become a regulatory concern for water pollution control. Recent work has suggested roadway stormwater runoff as a potential source of microbial pollutants. The objective of this study was to determine the impact of roadway runoff on the microbiological quality of receiving streams. Microbiological quality of roadway stormwater runoff and the receiving stream was monitored during storm events with both cultivation-dependent fecal bacteria enumeration and cultivation-independent high-throughput sequencing techniques. Enumeration of total coliforms as a measure of fecal microbial pollution found consistently lower total coliform counts in roadway runoff than those in the stream water, suggesting that roadway runoff was not a major contributor of microbial pollutants to the receiving stream. Further characterization of the microbial community in the stormwater samples by 16S ribosomal RNA gene-based high-throughput amplicon sequencing revealed significant differences in the microbial composition of stormwater runoff from the roadways and the receiving stream. The differences in microbial composition between the roadway runoff and stream water demonstrate that roadway runoff did not appear to have a major influence on the stream in terms of microbiological quality. Thus, results from both fecal bacteria enumeration and high-throughput amplicon sequencing techniques were consistent that roadway stormwater runoff was not the primary contributor of microbial loading to the stream. Further studies of additional watersheds with distinct characteristics are needed to validate these findings. Understanding gained in this study could support the development of more effective strategies for stormwater management in sensitive watersheds. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

    OpenAIRE

    Jiunian Guan; Baixing Yan; Hui Zhu; Yingying Xu

    2012-01-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting season...

  19. Herbicide volatilization trumps runoff losses, a multi-year investigation

    Science.gov (United States)

    Surface runoff and volatilization are two processes critical to herbicide off-site transport. To determine the relevance of these off-site transport mechanisms, runoff and turbulent vapor fluxes were simultaneously monitored on the same site for eight years. Site location, herbicide formulations, ...

  20. Impact of Climate Change on Runoff in the Gilgel Abbay Watershed, the Upper Blue Nile Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    Hailu Sheferaw Ayele

    2016-09-01

    Full Text Available Hydrological assessment is critical to the successful implementation of adaption measures. In this study, projections of seven global circulation models (GCMs associated with high and medium–low Representative Concentration Pathways (RCP 8.5 and RCP 4.5 for the period 2021–2040 and 2081–2100 were adopted to assess changes on runoffs in the Gilgel Abbay watershed, the upper Blue Nile basin. A weather generator was employed to generate daily temperature and precipitation to drive a hydrological model for impact assessment. Despite the projected magnitude of changes varied among different GCMs and RCPs, increasing runoffs in wet-season and decreasing in dry-season are observed in both periods, mainly attributed to the change in projected precipitation. Such changes are profound in cases of RCP 8.5 with respect to those of RCP 4.5 and in cases of 2081–2100 with respect to those of 2021–2040. Although the increasing runoffs would provide greater inflow to Lake Tana, the increase of precipitation in wet-season would imply a higher possibility of flash floods. On the other hand, decrease runoffs in dry-season further intensify existing shortage of irrigation water demand. These changes will have deleterious consequences on the economic wellbeing of the country and require successful implementation of adaption measures to reduce vulnerability.

  1. Detecting surface runoff location in a small catchment using distributed and simple observation method

    Science.gov (United States)

    Dehotin, Judicaël; Breil, Pascal; Braud, Isabelle; de Lavenne, Alban; Lagouy, Mickaël; Sarrazin, Benoît

    2015-06-01

    Surface runoff is one of the hydrological processes involved in floods, pollution transfer, soil erosion and mudslide. Many models allow the simulation and the mapping of surface runoff and erosion hazards. Field observations of this hydrological process are not common although they are crucial to evaluate surface runoff models and to investigate or assess different kinds of hazards linked to this process. In this study, a simple field monitoring network is implemented to assess the relevance of a surface runoff susceptibility mapping method. The network is based on spatially distributed observations (nine different locations in the catchment) of soil water content and rainfall events. These data are analyzed to determine if surface runoff occurs. Two surface runoff mechanisms are considered: surface runoff by saturation of the soil surface horizon and surface runoff by infiltration excess (also called hortonian runoff). The monitoring strategy includes continuous records of soil surface water content and rainfall with a 5 min time step. Soil infiltration capacity time series are calculated using field soil water content and in situ measurements of soil hydraulic conductivity. Comparison of soil infiltration capacity and rainfall intensity time series allows detecting the occurrence of surface runoff by infiltration-excess. Comparison of surface soil water content with saturated water content values allows detecting the occurrence of surface runoff by saturation of the soil surface horizon. Automatic records were complemented with direct field observations of surface runoff in the experimental catchment after each significant rainfall event. The presented observation method allows the identification of fast and short-lived surface runoff processes at a small spatial and temporal resolution in natural conditions. The results also highlight the relationship between surface runoff and factors usually integrated in surface runoff mapping such as topography, rainfall

  2. Runoff generation in a Mediterranean semi-arid landscape: Thresholds, scale, rainfall and catchment characteristics

    Science.gov (United States)

    Ries, Fabian; Schmidt, Sebastian; Sauter, Martin; Lange, Jens

    2016-04-01

    Surface runoff acts as an integrated response of catchment characteristics and hydrological processes. In the Eastern Mediterranean region, a lack of runoff data has hindered a better understanding of runoff generation processes on the catchment scale, despite the importance of surface runoff as a water resource or flood hazard. Our main aim was to identify and explain differences in catchment runoff reactions across a variety of scales. Over a period of five years, we observed runoff in ephemeral streams of seven watersheds with sizes between 3 and 129 km2. Landuse and surface cover types (share of vegetation, bare soil and rock outcrops) were derived from aerial images by objective classification techniques. Using data from a dense rainfall network we analysed the effects of scale, catchment properties and aridity on runoff generation. Thereby we extracted rainfall and corresponding runoff events from our time-series to calculate event based rainfall characteristics and catchment runoff coefficients. Soil moisture observations provided additional information on antecedent moisture conditions, infiltration characteristics and the evolution of saturated areas. In contrast to the prevailing opinion that the proportion of Hortonian overland flow increases with aridity, we found that in our area the largest share (> 95 %) of runoff is generated by saturation excess overland flow in response to long lasting, rainfall events of high amount. This was supported by a strong correlation between event runoff and precipitation totals. Similar rainfall thresholds (50 mm) for runoff generation were observed in all investigated catchments. No scale effects on runoff coefficients were found; instead we identified up to three-fold runoff coefficients in catchments with larger extension of arid areas, higher percentage of rock outcrops and urbanization. Comparing two headwater catchments with noticeable differences in extent of olive orchards, no difference in runoff generation was

  3. ARIES CATCHMENT UPPER AND MIDDLE COURSE SMALL STREAMS SEASONAL RUNOFF REGIME CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    CS. HORVATH

    2013-03-01

    Full Text Available The study is based on the processing and interpreting data from 16 gauging stations, of which 10 control catchments smaller than 150 km2 and so reflects more faithfully the local characteristics of the runoff. To highlight the runoff regime features during the year we selected three periods (1950-1967, 1950-2009 and 1970-2009. The geographical features of the central eastern part of the Apuseni Mountains, especially the climatic and geomorphic characteristics, are faithfully reflected in the rivers runoff regime. So, on all rivers the dominant is the spring runoff and the lowest percentage of the total annual average water volume is measured in the winter. Distribution and frequency of the richest (March, April and May and the poorest (January, February, August and September average runoff months vary according to the catchments altitude. The multiannual seasonal and monthly variation of the runoff was highlighted by the coefficients of variation. The study reveals that the rhythmic structure of the runoff regime reflects the local supply, the geological conditions and the reliefs morphological and morphometric characteristics.

  4. Observations of Pronounced Greenland Ice Sheet Firn Warming and Implications for Runoff Production

    Science.gov (United States)

    Polashenski, Chris; Courville, Zoe; Benson, Carl; Wagner, Anna; Chen, Justin; Wong, Gifford; Hawley, Robert; Hall, Dorothy

    2014-01-01

    Field measurements of shallow borehole temperatures in firn across the northern Greenland ice sheet are collected during May 2013. Sites first measured in 19521955 are revisited, showing long-term trends in firn temperature. Results indicate a pattern of substantial firn warming (up to +5.7C) at midlevel elevations (1400-2500 m) and little temperature change at high elevations (2500 m). We find that latent heat transport into the firn due to meltwater percolation drives the observed warming. Modeling shows that heat is stored at depth for several years, and energy delivered from consecutive melt events accumulates in the firn. The observed warming is likely not yet in equilibrium with recent melt production rates but captures the progression of sites in the percolation facies toward net runoff production.

  5. The effect of the runoff size on the pesticide concentration in runoff water and in FOCUS streams simulated by PRZM and TOXSWA

    NARCIS (Netherlands)

    Adriaanse, Pauline; Leerdam, van R.C.; Boesten, Jos J.T.I.

    2017-01-01

    Within the European Union the exposure of aquatic organisms to pesticides is assessed by simulations with the so-called FOCUS Surface Water Scenarios. Runoff plays an important role in these scenarios. As little is known about the effect of runoff size on the exposure, we investigated the effect of

  6. Characteristics of Phosphorus Runoff Losses from Typical Paddy Fields in Guangdong Province, China

    Directory of Open Access Journals (Sweden)

    NING Jian-feng

    2018-03-01

    Full Text Available Three experimental paddy fields located in the city of Zengcheng, Qingyuan and Gaozhou in Guangdong Province were selected to monitor the runoff losses of phosphorus from the year of 2008 to 2012. The results showed that runoff event in paddy field occurred mainly in the early rice season. The runoff concentration of total phosphorus(TP under conventional fertilization treatment was in the range of 0.02~1.56 mg·L-1. It was recorded that TP concentration in 11%~18% of the total runoff samples exceeded the grade Ⅴ of the national surface water environmental quality(0.4 mg·L-1. Peak concentration of different phosphorus forms[TP, dissolved total P(DTP and particulate P(PP] were observed within 14 days after fertilization, which indicated the high environmental pollution risk of phosphorus during this period. Application of phosphorus fertilizer increased runoff load of DTP in paddy field and showed no effect on that of PP and TP. The annual runoff loads of 0.63~4.05, 0.33~2.91 kg·hm-2 and 1.10~6.68 kg·hm-2 for DTP, PP and TP, respectively, were recorded under conventional fertilizer model. Runoff load of phosphorus exhibited wide spatial and temporal variation during experimental period. Runoff coefficient of 0.06%~6.81% of phosphorus was recorded. It was observed that DTP dominated the phosphorus runoff load. Phosphorus runoff losses from paddy field was affected by a variety of natural and human factors, and fertilization, precipitation and runoff volume were identified as the main factors.

  7. Electron temperature measurements in lowdensity plasmas by helium spectroscopy

    International Nuclear Information System (INIS)

    Brenning, N.

    1977-09-01

    This method to use relative intensities of singlet and triplet lines of neutral helium to measure electron temperature in low-density plasmas is examined. Calculations from measured and theoretical data about transitions in neutral helium are carried out and compared to experimental results. It is found that relative intensities of singlet and triplet lines from neutral helium only can be used for TE determination in low-density, short-duration plasmas. The most important limiting processes are excitation from the metastable 2 3 S level and excitation transfer in collisions between electrons and excited helium atoms. An evaluation method is suggested, which minimizes the effect of these processes. (author)

  8. Beyond the SCS-CN method: A theoretical framework for spatially lumped rainfall-runoff response

    Science.gov (United States)

    Bartlett, M. S.; Parolari, A. J.; McDonnell, J. J.; Porporato, A.

    2016-06-01

    Since its introduction in 1954, the Soil Conservation Service curve number (SCS-CN) method has become the standard tool, in practice, for estimating an event-based rainfall-runoff response. However, because of its empirical origins, the SCS-CN method is restricted to certain geographic regions and land use types. Moreover, it does not describe the spatial variability of runoff. To move beyond these limitations, we present a new theoretical framework for spatially lumped, event-based rainfall-runoff modeling. In this framework, we describe the spatially lumped runoff model as a point description of runoff that is upscaled to a watershed area based on probability distributions that are representative of watershed heterogeneities. The framework accommodates different runoff concepts and distributions of heterogeneities, and in doing so, it provides an implicit spatial description of runoff variability. Heterogeneity in storage capacity and soil moisture are the basis for upscaling a point runoff response and linking ecohydrological processes to runoff modeling. For the framework, we consider two different runoff responses for fractions of the watershed area: "prethreshold" and "threshold-excess" runoff. These occur before and after infiltration exceeds a storage capacity threshold. Our application of the framework results in a new model (called SCS-CNx) that extends the SCS-CN method with the prethreshold and threshold-excess runoff mechanisms and an implicit spatial description of runoff. We show proof of concept in four forested watersheds and further that the resulting model may better represent geographic regions and site types that previously have been beyond the scope of the traditional SCS-CN method.

  9. Functional approach to exploring climatic and landscape controls of runoff generation: 1. Behavioral constraints on runoff volume

    Science.gov (United States)

    Li, Hong-Yi; Sivapalan, Murugesu; Tian, Fuqiang; Harman, Ciaran

    2014-12-01

    Inspired by the Dunne diagram, the climatic and landscape controls on the partitioning of annual runoff into its various components (Hortonian and Dunne overland flow and subsurface stormflow) are assessed quantitatively, from a purely theoretical perspective. A simple distributed hydrologic model has been built sufficient to simulate the effects of different combinations of climate, soil, and topography on the runoff generation processes. The model is driven by a sequence of simple hypothetical precipitation events, for a large combination of climate and landscape properties, and hydrologic responses at the catchment scale are obtained through aggregation of grid-scale responses. It is found, first, that the water balance responses, including relative contributions of different runoff generation mechanisms, could be related to a small set of dimensionless similarity parameters. These capture the competition between the wetting, drying, storage, and drainage functions underlying the catchment responses, and in this way, provide a quantitative approximation of the conceptual Dunne diagram. Second, only a subset of all hypothetical catchment/climate combinations is found to be "behavioral," in terms of falling sufficiently close to the Budyko curve, describing mean annual runoff as a function of climate aridity. Furthermore, these behavioral combinations are mostly consistent with the qualitative picture presented in the Dunne diagram, indicating clearly the commonality between the Budyko curve and the Dunne diagram. These analyses also suggest clear interrelationships amongst the "behavioral" climate, soil, and topography parameter combinations, implying these catchment properties may be constrained to be codependent in order to satisfy the Budyko curve.

  10. Profile modification and hot electron temperature from resonant absorption at modest intensity

    International Nuclear Information System (INIS)

    Albritton, J.R.; Langdon, A.B.

    1980-01-01

    Resonant absorption is investigated in expanding plasmas. The momentum deposition associated with the ejection of hot electrons toward low density via wavebreaking readily exceeds that of the incident laser radiation and results in significant modification of the density profile at critical. New scaling of hot electron temperature with laser and plasma parameters is presented

  11. Estimation of potential runoff-contributing areas in Kansas using topographic and soil information

    Science.gov (United States)

    Juracek, Kyle E.

    1999-01-01

    Digital topographic and soil information was used to estimate potential runoff-contributing areas throughout Kansas. The results then were used to compare 91 selected subbasins representing soil, slope, and runoff variability. Potential runoff-contributing areas were estimated collectively for the processes of infiltration-excess and saturation-excess overland flow using a set of environmental conditions that represented very high, high, moderate, low, very low, and extremely low potential runoff. For infiltration-excess overland flow, various rainfall-intensity and soil-permeability values were used. For saturation-excess overland flow, antecedent soil-moisture conditions and a topographic wetness index were used. Results indicated that very low potential-runoff conditions provided the best ability to distinguish the 91 selected subbasins as having relatively high or low potential runoff. The majority of the subbasins with relatively high potential runoff are located in the eastern half of the State where soil permeability generally is less and precipitation typically is greater. The ability to distinguish the subbasins as having relatively high or low potential runoff was possible mostly due to the variability of soil permeability across the State.

  12. Large-scale runoff generation - parsimonious parameterisation using high-resolution topography

    Science.gov (United States)

    Gong, L.; Halldin, S.; Xu, C.-Y.

    2011-08-01

    World water resources have primarily been analysed by global-scale hydrological models in the last decades. Runoff generation in many of these models are based on process formulations developed at catchments scales. The division between slow runoff (baseflow) and fast runoff is primarily governed by slope and spatial distribution of effective water storage capacity, both acting at very small scales. Many hydrological models, e.g. VIC, account for the spatial storage variability in terms of statistical distributions; such models are generally proven to perform well. The statistical approaches, however, use the same runoff-generation parameters everywhere in a basin. The TOPMODEL concept, on the other hand, links the effective maximum storage capacity with real-world topography. Recent availability of global high-quality, high-resolution topographic data makes TOPMODEL attractive as a basis for a physically-based runoff-generation algorithm at large scales, even if its assumptions are not valid in flat terrain or for deep groundwater systems. We present a new runoff-generation algorithm for large-scale hydrology based on TOPMODEL concepts intended to overcome these problems. The TRG (topography-derived runoff generation) algorithm relaxes the TOPMODEL equilibrium assumption so baseflow generation is not tied to topography. TRG only uses the topographic index to distribute average storage to each topographic index class. The maximum storage capacity is proportional to the range of topographic index and is scaled by one parameter. The distribution of storage capacity within large-scale grid cells is obtained numerically through topographic analysis. The new topography-derived distribution function is then inserted into a runoff-generation framework similar VIC's. Different basin parts are parameterised by different storage capacities, and different shapes of the storage-distribution curves depend on their topographic characteristics. The TRG algorithm is driven by the

  13. Effect of Land Use and Climate Change on Runoff in the Dongjiang Basin of South China

    Directory of Open Access Journals (Sweden)

    Yanhu He

    2013-01-01

    Full Text Available Variability and availability of water resources under changing environment in a regional scale have been hot topics in recent years, due to the vulnerability of water resources associated with social and economic development. In this paper, four subbasins in the Dongjiang basin with a significant land use change were selected as case study. Runoffs of the four subbasins were simulated using the SCS monthly model to identify the quantitative impacts of land use and climate change. The results showed that (1, in the Dongjiang basin, temperature increased significantly, evaporation and sunlight decreased strongly, while precipitation showed a nonsignificant increase; (2 since the 1980s, land uses in the Dongjiang basin have experienced a significant change with a prominent increase in urban areas, a moderate increase in farmlands, and a great decrease in forest areas; (3 the SCS monthly model performed well in the four subbasins giving that the more significant land use change in each subbasin, the more runoff change correspondingly; (4 overall, runoff change was contributed half and half by climate change and human activities, respectively, in all the subbasins, in which about 20%~30% change was contributed by land use change.

  14. Constraining Glacial Runoff Contributions to Water Resources in the Cordillera Real, Bolivia using Environmental Tracers

    Science.gov (United States)

    Guido, Z.; McIntosh, J. C.; Papuga, S. A.

    2013-12-01

    Warming temperatures in recent decades have contributed to substantial reductions in glaciers in many mountain regions around the globe, including the South American Andes. Melting of these glaciers taps water resources accumulated in past climates, and the diminishing ice marks a decrease in a nonrenewable water source that begs the question: how will future water supplies be impacted by climate change. Water resource management and climate adaptation efforts can be informed by knowledge of the extent to which glaciers contribute to seasonal streamflows, but remote locations and scant monitoring often limit this quantification. In Bolivia, more than two million people draw water from watersheds fed, in part, by glaciers. The amount to which these glaciers contribute to the water supply, however, is not well constrained. We apply elemental and isotopic tracers in an end-member mixing model to quantify glacial runoff contributions to local water supplies. We present oxygen and deuterium isotopes and major anion concentrations (sulfate and chloride) of shallow groundwater, streams, reservoirs, small arroyos, and glacial runoff. Isotopic and anion mixing models suggest between 45-67% of the water measured in high altitude streams originated from within the glacial footprint during the 2011 wet season, while glacial runoff contributed about 42-53% of the water in reservoirs in the 2012 dry season. Data also show that shallow groundwater is connected to glacial-fed streams. Any future decrease in glacial runoff may contribute to a reduction in surface water supplies and lower groundwater levels downstream, perhaps below the depth of hand-dug wells common in rural communities.

  15. Ion temperature effects on magnetotail Alfvén wave propagation and electron energization: ION TEMPERATURE EFFECTS ON ALFVÉN WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Damiano, P. A. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Johnson, J. R. [Princeton Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton University, Princeton New Jersey USA; Chaston, C. C. [Space Sciences Laboratory, University of California, Berkeley California USA; School of Physics, University of Sydney, Sydney New South Wales Australia

    2015-07-01

    A new 2-D self-consistent hybrid gyrofluid-kinetic electron model in dipolar coordinates is presented and used to simulate dispersive-scale Alfvén wave pulse propagation from the equator to the ionosphere along an L = 10 magnetic field line. The model is an extension of the hybrid MHD-kinetic electron model that incorporates ion Larmor radius corrections via the kinetic fluid model of Cheng and Johnson (1999). It is found that consideration of a realistic ion to electron temperature ratio decreases the propagation time of the wave from the plasma sheet to the ionosphere by several seconds relative to a ρi=0 case (which also implies shorter timing for a substorm onset signal) and leads to significant dispersion of wave energy perpendicular to the ambient magnetic field. Additionally, ion temperature effects reduce the parallel current and electron energization all along the field line for the same magnitude perpendicular electric field perturbation.

  16. Packaging Technologies for High Temperature Electronics and Sensors

    Science.gov (United States)

    Chen, Liangyu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

    2013-01-01

    This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500degC silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chiplevel packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550degC. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500degC for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500degC are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

  17. The electronic temperature control and measurements reactor fuel rig circuits

    International Nuclear Information System (INIS)

    Glowacki, S.W.

    1980-01-01

    The electronic circuits of two digital temperature meters developed for the thermocouple of Ni-NiCr type are described. The output thermocouple signal as converted by means of voltage-to-freguency converter. The frequency is measured by a digital scaler controled by quartz generator signals. One of the described meter is coupled with digital temperature controler which drives the power stage of the reactor rig heater. The internal rig temperature is measured by the thermocouple providing the input signal to the mentioned voltage-to-frequency converter, that means the circuits work in the negative feedback loop. The converter frequency-to-voltage ratio is automatically adjusted to match to thermocouple sensitivity changes in the course of the temperature variations. The accuracy of measuring system is of order of +- 1degC for thermocouple temperature changes from 523 K up to 973 K (50degC up to 700degC). (author)

  18. Characterizations of the first flush in storm water runoff from an urban roadway.

    Science.gov (United States)

    Lee, B C; Matsui, S; Shimizu, Y; Matsuda, T

    2005-07-01

    Storm water runoff from urban roadways contains anthropogenic pollutants, which are mainly generated from traffic-related activities. The purpose of this study was to evaluate the characteristics of pollutants from the roadway runoff as well as first flush effects. Storm water runoff was sampled during five storm events from the experimental site in Otsu, Shiga, Japan. From the hydrographs and pollutographs for the roadway runoff, the concentration of pollutants increased with increasing runoff flow in the low flow rate event, but did not significantly increase in the high flow rate event. Moreover, according to the analysis of cumulative pollutant mass versus runoff volume curves from five storm events, the first 50% of the runoff volume transported 62% of TOC and Mo, 60% of SS, 59% of Fe, Mn and Cu, 58% of Ni, 57% of Cd and Pb, 56% of Al, 55% of Zn, and 54% of Cr, as the mean values. The first 30% and 80% of the runoff volume also transported 34-43% mass of the pollutants and 82-88% mass of the pollutants, respectively. This study for storm water runoff may also provide useful information to correctly design treatment facilities, such as detention tanks and ponds, filtration and adsorption systems.

  19. Impact of Animal Waste Application on Runoff Water Quality in Field Experimental Plots

    Directory of Open Access Journals (Sweden)

    Paul B. Tchounwou

    2005-08-01

    Full Text Available Animal waste from dairy and poultry operations is an economical and commonly used fertilizer in the state of Louisiana. The application of animal waste to pasture lands not only is a source of fertilizer, but also allows for a convenient method of waste disposal. The disposal of animal wastes on land is a potential nonpoint source of water degradation. Water degradation and human health is a major concern when considering the disposal of large quantities of animal waste. The objective of this research was to determine the effect of animal waste application on biological (fecal coliform, Enterobacter spp. and Escherichia coli and physical/chemical (temperature, pH, nitrate nitrogen, ammonia nitrogen, phosphate, copper, zinc, and sulfate characteristics of runoff water in experimental plots. The effects of the application of animal waste have been evaluated by utilizing experimental plots and simulated rainfall events. Samples of runoff water were collected and analyzed for fecal coliforms. Fecal coliforms isolated from these samples were identified to the species level. Chemical analysis was performed following standard test protocols. An analysis of temperature, ammonia nitrogen, nitrate nitrogen, iron, copper, phosphate, potassium, sulfate, zinc and bacterial levels was performed following standard test protocols as presented in Standard Methods for the Examination of Water and Wastewater [1]. In the experimental plots, less time was required in the tilled broiler litter plots for the measured chemicals to decrease below the initial pre-treatment levels. A decrease of over 50% was noted between the first and second rainfall events for sulfate levels. This decrease was seen after only four simulated rainfall events in tilled broiler litter plots whereas broiler litter plots required eight simulated rainfall events to show this same type of reduction. A reverse trend was seen in the broiler litter plots and the tilled broiler plots for potassium

  20. Diffuse emission and control of copper in urban surface runoff.

    Science.gov (United States)

    Boller, M A; Steiner, M

    2002-01-01

    Copper washed off from roofs and roads is considered to be a major contribution to diffuse copper pollution of urban environments. In order to guarantee sustainable protection of soils and water, the long-term strategy is to avoid or replace copper containing materials on roofs and fagades. Until achievement of this goal, a special adsorber system is suggested to control the diffuse copper fluxes by retention of copper by a mixture of granulated iron-hydroxide (GEH) and calcium carbonate. Since future stormwater runoff concepts are based on decentralised runoff infiltration into the underground, solutions are proposed which provide for copper retention in infiltration sites using GEH adsorption layers. The example of a large copper façade of which the runoff is treated in an adsorption trench reveals the first full-scale data on façade runoff and adsorber performance. During the first year of investigation average façade runoff concentrations in the range of 1-10 mg Cu/l are reduced by 96-99% in the adsorption ditch.

  1. Rainfall-induced runoff from exposed streambed sediments: an important source of water pollution.

    Science.gov (United States)

    Frey, S K; Gottschall, N; Wilkes, G; Grégoire, D S; Topp, E; Pintar, K D M; Sunohara, M; Marti, R; Lapen, D R

    2015-01-01

    When surface water levels decline, exposed streambed sediments can be mobilized and washed into the water course when subjected to erosive rainfall. In this study, rainfall simulations were conducted over exposed sediments along stream banks at four distinct locations in an agriculturally dominated river basin with the objective of quantifying the potential for contaminant loading from these often overlooked runoff source areas. At each location, simulations were performed at three different sites. Nitrogen, phosphorus, sediment, fecal indicator bacteria, pathogenic bacteria, and microbial source tracking (MST) markers were examined in both prerainfall sediments and rainfall-induced runoff water. Runoff generation and sediment mobilization occurred quickly (10-150 s) after rainfall initiation. Temporal trends in runoff concentrations were highly variable within and between locations. Total runoff event loads were considered large for many pollutants considered. For instance, the maximum observed total phosphorus runoff load was on the order of 1.5 kg ha. Results also demonstrate that runoff from exposed sediments can be a source of pathogenic bacteria. spp. and spp. were present in runoff from one and three locations, respectively. Ruminant MST markers were also present in runoff from two locations, one of which hosted pasturing cattle with stream access. Overall, this study demonstrated that rainfall-induced runoff from exposed streambed sediments can be an important source of surface water pollution. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Thomson scattering on argon surfatron plasmas at intermediate pressures: Axial profiles of the electron temperature and electron density

    International Nuclear Information System (INIS)

    Palomares, J.M.; Iordanova, E.; Veldhuizen, E.M. van; Baede, L.; Gamero, A.; Sola, A.; Mullen, J.J.A.M. van der

    2010-01-01

    The axial profiles of the electron density n e and electron temperature T e of argon surfatron plasmas in the pressure range of 6-20 mbar and microwave power between 32 and 82 W have been determined using Thomson Scattering of laser irradiation at 532 nm. For the electron density and temperature we found values in the ranges 5 x 10 18 e 19 m -3 and 1.1 e e and T e down to 8% and 3%, respectively. It is found that n e decreases in the direction of the wave propagation with a slope that is nearly constant. The slope depends on the pressure but not on the power. Just as predicted by theories we see that increasing the power leads to longer plasma columns. However, the plasmas are shorter than what is predicted by theories based on the assumption that for the plasma-wave interaction electron-atom collisions are of minor importance (the so-called collisionless regime). The plasma vanishes long before the critical value of the electron density is reached. In contrast to what is predicted by the positive column model it is found that T e does not stay constant along the column, but monotonically increases with the distance from the microwave launcher. Increases of more than 50% over 30 cm were found.

  3. Observations of temperature rise during electron cyclotron heating application in Proto-MPEX

    Science.gov (United States)

    Biewer, T. M.; Bigelow, T.; Caneses, J. F.; Diem, S. J.; Rapp, J.; Reinke, M.; Kafle, N.; Ray, H. B.; Showers, M.

    2017-10-01

    The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at ORNL utilizes a variety of power systems to generate and deliver a high heat flux plasma (1 MW/m2 for these discharges) onto the surface of material targets. In the experiments described here, up to 120 kW of 13.56 MHz ``helicon'' waves are combined with 20 kW of 28 GHz microwaves to produce Deuterium plasma discharges. The 28 GHz waves are launched in a region of the device where the magnetic field is axially varying near 0.8 T, resulting in the presence of a 2nd harmonic electron cyclotron heating (ECH) resonance layer that transects the plasma column. The electron density and temperature profiles are measured using a Thomson scattering (TS) diagnostic, and indicate that the electron density is radially peaked. In the core of the plasma column the electron density is higher than the cut-off density (0.9x1019 m-3) for ECH waves to propagate and O-X-B mode conversion into electron Bernstien waves (EBW) is expected. TS measurements indicate electron temperature increases during 28 GHz wave application, rising (from 5 eV to 20 eV) as the neutral Deuterium pressure is reduced below 1 mTorr. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725.

  4. Apparent increase in the thickness of superconducting particles at low temperatures measured by electron holography.

    Science.gov (United States)

    Hirsch, J E

    2013-10-01

    We predict that superconducting particles will show an apparent increase in thickness at low temperatures when measured by electron holography. This will result not from a real thickness increase, rather from an increase in the mean inner potential sensed by the electron wave traveling through the particle, originating in expansion of the electronic wavefunction of the superconducting electrons and resulting negative charge expulsion from the interior to the surface of the superconductor, giving rise to an increase in the phase shift of the electron wavefront going through the sample relative to the wavefront going through vacuum. The temperature dependence of the observed phase shifts will yield valuable new information on the physics of the superconducting state of metals. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Improving runoff prediction using agronomical information in a cropped, loess covered catchment

    NARCIS (Netherlands)

    Lefrancq, Marie; Van Dijk, Paul; Jetten, Victor; Schwob, Matthieu; Payraudeau, Sylvain

    2017-01-01

    Predicting runoff hot spots and hot-moments within a headwater crop-catchment is of the utmost importance to reduce adverse effects on aquatic ecosystems by adapting land use management to control runoff. Reliable predictions of runoff patterns during a crop growing season remain challenging. This

  6. Transport of oxytetracycline, chlortetracycline, and ivermectin in surface runoff from irrigated pasture.

    Science.gov (United States)

    Bair, Daniel A; Popova, Ina E; Tate, Kenneth W; Parikh, Sanjai J

    2017-09-02

    The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.

  7. [Monitoring and analysis on evolution process of rainfall runoff water quality in urban area].

    Science.gov (United States)

    Dong, Wen; Li, Huai-En; Li, Jia-Ke

    2013-02-01

    In order to find the water quality evolution law and pollution characteristics of the rainfall runoff from undisturbed to the neighborhood exit, 6 times evolution process of rainfall runoff water quality were monitored and analyzed from July to October in 2011, and contrasted the clarification efficiency of the grassland to the roof runoff rudimentarily at the same time. The research showed: 1. the results of the comparison from "undisturbed, rainfall-roof, rainfall runoff-road, rainfall-runoff the neighborhood exit runoff " showed that the water quality of the undisturbed rain was better than that from the roof and the neighborhood exist, but the road rainfall runoff water quality was the worst; 2. the average concentrations of the parameters such as COD, ammonia nitrogen and total nitrogen all exceeded the Fifth Class of the Surface Water Quality Standard except for the soluble total phosphorus from undisturbed rainfall to the neighborhood exit; 3. the runoff water quality of the short early fine days was better than that of long early fine days, and the last runoff water quality was better than that of the initial runoff in the same rainfall process; 4. the concentration reduction of the grassland was notable, and the reduction rate of the grassland which is 1.0 meter wide of the roof runoff pollutants such as COD and nitrogen reached 30%.

  8. Fill and spill drives runoff connectivity over frozen ground

    Science.gov (United States)

    Coles, A. E.; McDonnell, J. J.

    2018-03-01

    Snowmelt-runoff processes on frozen ground are poorly understood at the hillslope scale. This is especially true for hillslopes on the northern Great Plains of North America where long periods of snow-covered frozen ground with very shallow slopes mask any spatial patterns and process controls on connectivity and hillslope runoff generation. This study examines a 4.66 ha (46,600 m2) hillslope on the northern Great Plains during the 2014 spring snowmelt season to explore hillslope runoff processes. Specifically, we explore the spatial patterns of runoff production source areas and examine how surface topography and patterns of snow cover, snow water equivalent, soil water content, and thawed layer depth - which we measured on a 10 m grid across our 46,600 m2 hillslope - affect melt water partitioning and runoff connectivity. A key question was whether or not the controls on connectivity are consistent with the fill and spill mechanism found in rain-dominated and unfrozen soil domains. The contrast between the slow infiltration rates into frozen soil and the relatively fast rates of snowmelt delivery to the soil surface resulted in water accumulation in small depressions under the snowpack. Consequently, infiltration was minimal over the 12 day melt period. Instead, nested filling of micro- and meso-depressions was followed by macro-scale, whole-slope spilling. This spilling occurred when large patches of ponded water exceeded the storage capacity behind downslope micro barriers in the surface topography, and flows from them coalesced to drive a rapid increase in runoff at the hillslope outlet. These observations of ponded water and flowpaths followed mapable fill and spill locations based on 2 m resolution digital topographic analysis. Interestingly, while surface topography is relatively unimportant under unfrozen conditions at our site because of low relief and high infiltrability, surface topography shows episodically critical importance for connectivity and

  9. Enhancement in electron and ion temperatures due to solar flares as measured by SROSS-C2 satellite

    Directory of Open Access Journals (Sweden)

    D. K. Sharma

    2004-06-01

    Full Text Available The observations on the ionospheric electron and ion temperatures (Te and Ti measured by the RPA payload aboard the SROSS-C2 satellite have been used to study the effect of solar flares on ionospheric heating. The data on solar flare has been obtained from the National Geophysical Data Center (NGDC Boulder, Colorado (USA. It has been found that the electron and ion temperatures have a consistent enhancement during the solar flares on the dayside Earth's ionosphere. The estimated enhancement for the average electron temperature is from 1.3 to 1.9 times whereas for ion temperature it is from 1.2 to 1.4 times to the normal days average temperature. The enhancement of ionospheric temperatures due to solar flares is correlated with the diurnal variation of normal days' ionospheric temperatures. The solar flare does not have any significant effect on the nightside ionosphere. A comparison with the temperature obtained from the IRI-95 model also shows a similar enhancement.

  10. Electronically induced nuclear transitions - temperature dependence and Rabi oscillations

    International Nuclear Information System (INIS)

    Niez, J.J.

    2002-01-01

    This paper deals with a nucleus electromagnetically coupled with the bound states of its electronic surroundings. It describes the temperature dependence of its dynamics and the onset of potential Rabi oscillations by means of a Master Equation. The latter is generalized in order to account for possible strong resonances. Throughout the paper the approximation schemes are discussed and tested. (authors)

  11. Temperature profiles on the gadolinium surface during electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-03-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck`s law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author).

  12. Temperature profiles on the gadolinium surface during electron beam evaporation

    International Nuclear Information System (INIS)

    Ohba, Hironori; Shibata, Takemasa

    1995-01-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck's law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author)

  13. Rainfall, runoff and sediment transport in a Mediterranean mountainous catchment.

    Science.gov (United States)

    Tuset, J; Vericat, D; Batalla, R J

    2016-01-01

    The relation between rainfall, runoff, erosion and sediment transport is highly variable in Mediterranean catchments. Their relation can be modified by land use changes and climate oscillations that, ultimately, will control water and sediment yields. This paper analyses rainfall, runoff and sediment transport relations in a meso-scale Mediterranean mountain catchment, the Ribera Salada (NE Iberian Peninsula). A total of 73 floods recorded between November 2005 and November 2008 at the Inglabaga Sediment Transport Station (114.5 km(2)) have been analysed. Suspended sediment transport and flow discharge were measured continuously. Rainfall data was obtained by means of direct rain gauges and daily rainfall reconstructions from radar information. Results indicate that the annual sediment yield (2.3 t km(-1) y(-1) on average) and the flood-based runoff coefficients (4.1% on average) are low. The Ribera Salada presents a low geomorphological and hydrological activity compared with other Mediterranean mountain catchments. Pearson correlations between rainfall, runoff and sediment transport variables were obtained. The hydrological response of the catchment is controlled by the base flows. The magnitude of suspended sediment concentrations is largely correlated with flood magnitude, while sediment load is correlated with the amount of direct runoff. Multivariate analysis shows that total suspended load can be predicted by integrating rainfall and runoff variables. The total direct runoff is the variable with more weight in the equation. Finally, three main hydro-sedimentary phases within the hydrological year are defined in this catchment: (a) Winter, where the catchment produces only water and very little sediment; (b) Spring, where the majority of water and sediment is produced; and (c) Summer-Autumn, when little runoff is produced but significant amount of sediments is exported out of the catchment. Results show as land use and climate change may have an important

  14. Ice volume distribution and implications on runoff projections in a glacierized catchment

    Directory of Open Access Journals (Sweden)

    J. Gabbi

    2012-12-01

    Full Text Available A dense network of helicopter-based ground-penetrating radar (GPR measurements was used to determine the ice-thickness distribution in the Mauvoisin region. The comprehensive set of ice-thickness measurements was combined with an ice-thickness estimation approach for an accurate determination of the bedrock. A total ice volume of 3.69 ± 0.31 km3 and a maximum ice thickness of 290 m were found. The ice-thickness values were then employed as input for a combined glacio-hydrological model forced by most recent regional climate scenarios. This model provided glacier evolution and runoff projections for the period 2010–2100. Runoff projections of the measured initial ice volume distribution show an increase in annual runoff of 4% in the next two decades, followed by a persistent runoff decrease until 2100. Finally, we checked the influence of the ice-thickness distribution on runoff projections. Our analyses revealed that reliable estimates of the ice volume are essential for modelling future glacier and runoff evolution. Wrong estimations of the total ice volume might even lead to deviations of the predicted general runoff trend.

  15. [Effect of antecedent dry weather period on urban storm runoff pollution load].

    Science.gov (United States)

    Li, Li-qing; Yin, Cheng-qing; Kong, Ling-li; He, Qing-ci

    2007-10-01

    Twelve storm events were surveyed at Shilipu catchment in Wuhan City through three-year monitoring regime. The flow discharges, total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in runoff were measured to study the mechanism of urban stormwater runoff pollution. The relationship between the event pollution load and the antecedent dry weather period was identified to discuss the influence of the urban surface sanitation management, operation of sewer pipe maintenance and rainfall characteristics on the urban stormwater runoff pollution. It was found that the antecedent dry weather period and runoff amount were the important determining factors in the generation of urban stormwater runoff pollution. The event pollution load was positively correlated to the antecedent dry weather period between two rainfall events (R2 = 0.95, p pollution loads. The best regression equation to estimate pollution load for storm events was developed based on the antecedent dry weather period and runoff depth. Source control including improving urban street sweeping activities and operation of sewer pipe maintenance should be made to reduce the amount of available pollutant over the dry days. It is important alternative to control urban stormwater runoff pollution for Hanyang District.

  16. Determining of electron temperature profile on the cross section of a Tokamak, using ECE technique

    Directory of Open Access Journals (Sweden)

    M. Hosseinpour

    2007-06-01

    Full Text Available  In this paper we have used plasma electron cyclotron emissions at the second harmonic frequency of extraordinary mode to determine the temperature profile of the plasma produced in IR-T1 Tokamak. The emissions obtained at different frequencies by a 5-channel heterodyne receiver, have been analyzed to determine the spatial variation of the electron temperature on the plasma cross section. The results have been also used to show the three-dimensional time evolution of the temperature profile during the period of confinement.

  17. Finding high-temperature superconductors by metallizing the σ-bonding electrons

    International Nuclear Information System (INIS)

    Gao Miao; Lu Zhongyi; Xiang Tao

    2015-01-01

    Raising superconducting transition temperature (T_c) is an important task of fundamental research on superconductivity. It is also a prerequisite for the large scale application of superconductors. Since the microscopic mechanism of high-T_c superconductivity is unknown, the conventional approach for increasing T_c is either to apply high pressure to a material which has the potential to become superconducting, or to push it close to an antiferromagnetic or some other quantum instability point by chemical doping. In this article, the authors point out that another general approach for raising T_c is to lift the σ-bonding bands to the Fermi level, or to metallize the σ-bonding elections. This approach can increase the probability of finding a novel high-T_c superconductor because the coupling of σ-bonding electrons with phonons is generally strong and the superconducting transition induced by this interaction can occur at relatively high temperatures. After elucidating the underlying mechanism, the authors discuss a number of schemes to metallize σ-bonding electrons, and present their recent prediction for the crystalline and electronic structures of two potential high-T_c superconductors, Li_2B_3C and Li_3B_4C_2, with T_c higher than 50 K. (authors)

  18. Outcomes of tibial endovascular intervention in patients with poor pedal runoff.

    Science.gov (United States)

    Baer-Bositis, Hallie E; Hicks, Taylor D; Haidar, Georges M; Sideman, Matthew J; Pounds, Lori L; Davies, Mark G

    2018-06-01

    Tibial interventions for critical limb ischemia are now commonplace. The aim of this study was to examine the impact of pedal runoff on patient-centered outcomes after tibial endovascular intervention. A database of patients undergoing lower extremity endovascular interventions at a single urban academic medical center between 2006 and 2016 was retrospectively queried. Patients with critical ischemia (Rutherford 5 and 6) were identified. Preintervention angiograms were reviewed in all cases to assess pedal runoff. Each dorsalis pedis, lateral plantar, and medial plantar artery was assigned a score according to the reporting standards of the Society for Vascular Surgery (0, no stenosis >20%; 1, 21%-49% stenosis; 2, 50%-99% stenosis; 2.5, half or less of the vessel length occluded; 3, more than half the vessel length occluded). A foot score (dorsalis pedis + medial plantar + lateral plantar + 1) was calculated for each foot (1-10). Two runoff score groups were identified: good vs poor, runoff score of 6 (47% had a runoff score ≥7). Overall major adverse cardiac events were equivalent at 30 days after the procedure in both groups. At 5 years, vessels with compromised runoff (score ≥7) had significantly lower ulcer healing (25% ± 3% vs 73% ± 4%, mean ± standard error of the mean [SEM]) and a lower 5-year limb salvage rate (45% ± 6% vs 69% ± 4%, mean ± SEM) compared with those with good runoff (score runoff (score ≥7) had significantly lower clinical efficacy (23% ± 8% vs 38% ± 4%, mean ± SEM), amputation-free survival (32% ± 6% vs 48% ± 5%, mean ± SEM), and freedom from major adverse limb events (23% ± 9% vs 41% ± 8%, mean ± SEM) at 5 years compared with patients with good runoff (score runoff score can identify those patients who will not achieve ulcer healing and patient-centered outcomes after tibial intervention. Defining such subgroups will allow stratification of the patients and appropriate application of

  19. Surface Runoff of Pesticides from a Clay Loam Field in Sweden.

    Science.gov (United States)

    Larsbo, Mats; Sandin, Maria; Jarvis, Nick; Etana, Ararso; Kreuger, Jenny

    2016-07-01

    Pesticides stored at or close to the soil surface after field application can be mobilized and transported off the field when surface runoff occurs. The objective of our study was to quantify the potential pesticide losses in surface runoff from a conventionally managed agricultural field in a Swedish climate. This was achieved by measuring surface runoff volumes and concentrations in runoff of six spring-applied pesticides and autumn-applied glyphosate and its metabolite aminomethylphosphonic acid (AMPA). Measurements were performed for 3 yr both during the growing seasons and during intervening winter snowmelt periods on a clay loam field close to Uppsala. During growing seasons, surface runoff was generated on only five occasions during one 25-d period in 2012 when the infiltration capacity of the soil may have been reduced by structural degradation due to large cumulative rainfall amounts after harrowing. Concentrations in surface runoff exceeded Swedish water quality standards in all samples during this growing season for diflufenican and pirimicarb. Surface runoff was generated during three snowmelt periods during the winter of 2012-2013. All of the applied pesticides were found in snowmelt samples despite incorporation of residues by autumn plowing, degradation, and leaching into the soil profile during the period between spraying and sampling. Concentrations of glyphosate ranged from 0.12 to 7.4 μg L, and concentrations of AMPA ranged from 0 to 2.7 μg L. Our results indicate that temporal changes in hydraulic properties during the growing season and when the soil freezes during winter affect pesticide losses through surface runoff. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  20. Soil erosion-runoff relationships: insights from laboratory studies

    Science.gov (United States)

    Mamedov, Amrakh; Warrington, David; Levy, Guy

    2016-04-01

    Understanding the processes and mechanisms affecting runoff generation and subsequent soil erosion in semi-arid regions is essential for the development of improved soil and water conservation management practices. Using a drip type laboratory rain simulator, we studied runoff and soil erosion, and the relationships between them, in 60 semi-arid region soils varying in their intrinsic properties (e.g., texture, organic matter) under differing extrinsic conditions (e.g., rain properties, and conditions prevailing in the field soil). Both runoff and soil erosion were significantly affected by the intrinsic soil and rain properties, and soil conditions within agricultural fields or watersheds. The relationship between soil erosion and runoff was stronger when the rain kinetic energy was higher rather than lower, and could be expressed either as a linear or exponential function. Linear functions applied to certain limited cases associated with conditions that enhanced soil structure stability, (e.g., slow wetting, amending with soil stabilizers, minimum tillage in clay soils, and short duration exposure to rain). Exponential functions applied to most of the cases under conditions that tended to harm soil stability (e.g., fast wetting of soils, a wide range of antecedent soil water contents and rain kinetic energies, conventional tillage, following biosolid applications, irrigation with water of poor quality, consecutive rain simulations). The established relationships between runoff and soil erosion contributed to a better understanding of the mechanisms governing overland flow and soil loss, and could assist in (i) further development of soil erosion models and research techniques, and (ii) the design of more suitable management practices for soil and water conservation.

  1. Environmental variation and macrofauna response in a coastal area influenced by land runoff

    Science.gov (United States)

    Akoumianaki, Ioanna; Papaspyrou, Sokratis; Kormas, Konstantinos Ar.; Nicolaidou, Artemis

    2013-11-01

    Macrofauna community interactions with environmental variables in the water column (salinity, temperature, turbidity, transparency, suspended particulate matter, particulate organic matter, choloroplastic pigments) and in the sediment (granulometric variables, organic carbon and pigments) were investigated in a coastal area with high land runoff due to riverine and temporary stream discharges (Greece, Aegean Sea, Maliakos Gulf). Samples were taken along a distance-depositional gradient from the river mouth to the open sea at eight stations, at times of different precipitation regime from August 2000 to May 2001. The physical variables, such as transparency and median grain size, generally increased seawards, and parallelled the depositional gradient as opposed to measures of food inputs and hydrodynamic regime. High environmental heterogeneity was observed during peak precipitation. The total number of species increased seawards and from August (122 species) to May (170 species). Maximum abundance also increased from August (4953 m-2) to May (10,220 individuals m-2), irrespective of distance from river mouth. Species belonging to different functional groups, as to recolonization, feeding, motility and substrate preferences, coexisted at all times indicating high functional diversity. Non-parametric multivariate regression showed that at times of low, rising and falling precipitation 78-81% of community variation was explained by environmental variables, indicating that macrofauna distribution and species composition respond to food inputs and sediment characteristics. During peak land runoff the community-environment relationship weakened (57% of the variability explained). The diversity of functional traits of the most abundant species indicates that the macrofauna community can absorb the impact of increased turbidity, sedimentation and current-driven dispersion. The study offers baseline information for the integrated coastal zone management in microtidal areas

  2. Assessment of pollution in road runoff using a Bufo viridis biological assay

    International Nuclear Information System (INIS)

    Dorchin, A.; Shanas, U.

    2010-01-01

    Road runoff is a major source of environmental pollution, significantly threatening nearby aquatic habitats. Chemical analyses indicate high pollutant concentrations in the road's 'first flush', but bioassays are more advantageous for addressing the cumulative effects of the numerous pollutants within the runoff. We used Bufo viridis embryos and larvae to assess the toxicity of road runoff from two major highways in Israel. We show, for the first time, that exposure to midseason runoff not only has an adverse effect on growth and development rates of B. viridis larvae but can also lead to increased rates of morphological deformations. Seasonal first flushes, despite having higher metal concentrations, did not adversely affect the toad larvae, apparently due to a counter effect of organic matter that potentially served as a supplementary energy resource. Road runoff can be a major cause for a qualitative decrease in the quality of aquatic habitats threatening amphibians in Israel. - Highway runoff has detrimental effects on the development of B. viridis larvae.

  3. Roofing Materials Assessment: Investigation of Five Metals in Runoff from Roofing Materials.

    Science.gov (United States)

    Winters, Nancy; Granuke, Kyle; McCall, Melissa

    2015-09-01

    To assess the contribution of five toxic metals from new roofing materials to stormwater, runoff was collected from 14 types of roofing materials and controls during 20 rain events and analyzed for metals. Many of the new roofing materials evaluated did not show elevated metals concentrations in the runoff. Runoff from several other roofing materials was significantly higher than the controls for arsenic, copper, and zinc. Notably, treated wood shakes released arsenic and copper, copper roofing released copper, PVC roofing released arsenic, and Zincalume® and EPDM roofing released zinc. For the runoff from some of the roofing materials, metals concentrations decreased significantly over an approximately one-year period of aging. Metals concentrations in runoff were demonstrated to depend on a number of factors, such as roofing materials, age of the materials, and climatic conditions. Thus, application of runoff concentrations from roofing materials to estimate basin-wide releases should be undertaken cautiously.

  4. Effect of electronic contribution on temperature-dependent thermal transport of antimony telluride thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won-Yong; Park, No-Won [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hong, Ji-Eun [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Yoon, Soon-Gil, E-mail: sgyoon@cnu.ac.kr [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Koh, Jung-Hyuk [School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Sang-Kwon, E-mail: sangkwonlee@cau.ac.kr [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2015-01-25

    Highlights: • We investigated thermal transport of the antimony telluride thin films. • The contribution of the electronic thermal conductivity increased up to ∼77% at 300 K. • We theoretically analyze and explain the high contribution of electronic component. - Abstract: We study the theoretical and experimental characteristics of thermal transport of 100 nm and 500 nm-thick antimony telluride (Sb{sub 2}Te{sub 3}) thin films prepared by radio frequency magnetron sputtering. The thermal conductivity was measured at temperatures ranging from 20 to 300 K, using four-point-probe 3-ω method. Out-of-plane thermal conductivity of the Sb{sub 2}Te{sub 3} thin film was much lesser in comparison to the bulk material in the entire temperature range, confirming that the phonon- and electron-boundary scattering are enhanced in thin films. Moreover, we found that the contribution of the electronic thermal conductivity (κ{sub e}) in total thermal conductivity (κ) linearly increased up to ∼77% at 300 K with increasing temperature. We theoretically analyze and explain the high contribution of electronic component of thermal conductivity towards the total thermal conductivity of the film by a modified Callaway model. Further, we find the theoretical model predictions to correspond well with the experimental results.

  5. [Research on spatial differentiation of urban stormwater runoff quality by source area monitoring].

    Science.gov (United States)

    Li, Li-Qing; Zhu, Ren-Xiao; Guo, Shu-Gang; Yin, Cheng-Qing

    2010-12-01

    Runoff samples were collected from 14 source areas in Hanyang district during four rain events in an attempt to investigate the spatial differentiation and influencing factors of urban stormwater runoff quality. The outcomes are expected to offer practical guidance in sources control of urban runoff pollution. The results revealed that particle-bound proportion of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in stormwater runoff were 58% +/- 17%, 65% +/- 13% and 92% +/- 6%, respectively. The fractions of ammonia, nitrate and dissolved organic nitrogen were homogeneous in dissolved nitrogen composition. Urban surface function, traffic volume, land use, population density, and street sweeping practice are the main factors determining spatial differentiation of urban surface runoff quality. The highest magnitude of urban stormwater runoff pollution was expected in the old urban residential area, followed by general residential with restaurants, commercial and transport area, new developments and green land. In addition, the magnitude of road stormwater runoff pollution is positively correlated to traffic volume, in the following order: the first trunk road > the second trunk road > minor road. Street sweeping and critical source areas controls should be implemented to mitigate the adverse effects of urban stormwater runoff on receive waters.

  6. Temperature distribution induced by electron beam in a closed cavity

    International Nuclear Information System (INIS)

    Molhem, A.G.; Soulayman, S.Sh.

    2004-01-01

    In order to investigate heat transfer phenomena induced by EB in a closed cavity an experimental arrangement, which allows generating and focusing an electron beam in to closed cavity within 1 mm in diameter and measuring temperature all over any perpendicular section to the EB, is used for this purpose. Experimental data show that the radial distribution of current density and temperature is normal with pressure and location dependent parameters. Moreover, there is two distinguishable regions in the EB: one is central while the other surrounds the first one. (orig.)

  7. Simulation and assessment of urbanization impacts on runoff metrics

    DEFF Research Database (Denmark)

    Zhang, Yongyong; Xia, Jun; Yu, Jingjie

    2018-01-01

    changes. The Qing River catchment as a peri-urban catchment in the Beijing metropolitan area is selected as our study region. Results show that: (1) the dryland agriculture is decreased from 13.9% to 1.5% of the total catchment area in the years 2000–2015, while the percentages of impervious surface...... information for urban planning such as Sponge City design.......Urbanization-induced landuse changes alter runoff regimes in complex ways. In this study, a detailed investigation of the urbanization impacts on runoff regimes is provided by using multiple runoff metrics and with consideration of landuse dynamics. A catchment hydrological model is modified...

  8. DETERMINATION OF CHARACTERISTICS MAXIMAL RUNOFF MOUNTAIN RIVERS IN CRIMEA

    Directory of Open Access Journals (Sweden)

    V. A. Ovcharuk

    2016-05-01

    Full Text Available This article has been examined maximum runoff of the rivers of theCrimeanMountains. The rivers flow through the western and eastern part of the northern slope Crimean Mountains, and on its southern coast. The largest of them: Belbek, Alma, Salgir, Su-Indol and others. To characterize the maximum runoff of rain floods (the layers of rain floods and maximum discharge of water on the rivers of the Crimean Mountains were used materials of observations for long-term period (from the beginning of observations to 2010 inclusive on 54 of streamflow station with using a the so-called «operator» model for maximum runoff formation.

  9. Measurement and modeling of diclosulam runoff under the influence of simulated severe rainfall.

    Science.gov (United States)

    van Wesenbeeck, I J; Peacock, A L; Havens, P L

    2001-01-01

    A runoff study was conducted near Tifton, GA to measure the losses of water, sediment, and diclosulam (N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro-[1,2,4]triazolo-[1,5c]-pyrimidine- 2-sulfonamide), a new broadleaf herbicide, under a 50-mm-in-3-h simulated rainfall event on three separate 0.05-ha plots. Results of a runoff study were used to validate the Pesticide Root Zone Model (PRZM, v. 3.12) using field-measured soil, chemical, and weather inputs. The model-predicted edge-of-field diclosulam loading was within 1% of the average observed diclosulam runoff from the field study; however, partitioning between phases was not as well predicted. The model was subsequently used with worst-case agricultural practice inputs and a 41-yr weather record from Dublin, GA to simulate edge-of-field runoff losses for the two most prevalent soils (Tifton and Bibb) in the southeastern U.S. peanut (Arachis hypogaea L.) market for 328 simulation years, and showed that the 90th percentile runoff amounts, expressed as percent of applied diclosulam, were 1.8, 0.6, and 5.2% for the runoff study plots and Tifton and Bibb soils, respectively. The runoff study and modeling indicated that more than 97% of the total diclosulam runoff was transported off the field by water, with < 3% associated with the sediment. Diclosulam losses due to runoff can be further reduced by lower application rates, tillage and crop residue management practices that reduce edge-of-field runoff, and conservation practices such as vegetated filter strips.

  10. Estimation of Runoff for Ozat Catchment using RS and GIS Based SCS-CN Method

    OpenAIRE

    Dipesh B. Chavda1,; Jaydip J. Makwana*2,; Hitesh V. Parmar3; Arvind N. Kunapara2; Girish V. Prajapati

    2016-01-01

    Estimation of runoff in a watershed is a prerequisite for design of hydraulic structures, reservoir operation and for soil erosion control measures. Water resource planning and management is important and critical issue in arid and semi-arid regions. Runoff from a watershed affected by several geo-morphological parameters and for a particular watershed land use change can affect the runoff volume and runoff rate significantly. Several methods are investigated to estimate the surface runoff fr...

  11. Urban runoff forecasting with ensemble weather predictions

    DEFF Research Database (Denmark)

    Pedersen, Jonas Wied; Courdent, Vianney Augustin Thomas; Vezzaro, Luca

    This research shows how ensemble weather forecasts can be used to generate urban runoff forecasts up to 53 hours into the future. The results highlight systematic differences between ensemble members that needs to be accounted for when these forecasts are used in practice.......This research shows how ensemble weather forecasts can be used to generate urban runoff forecasts up to 53 hours into the future. The results highlight systematic differences between ensemble members that needs to be accounted for when these forecasts are used in practice....

  12. Evaluation of Livestock Runoff as a Source of Water Polution in Northern Utah

    OpenAIRE

    Wieneke, Stephen T.; George, Dennis B.; Filip, Daniel S.; Finney, Brad

    1980-01-01

    A mathematical model was developed to predict the impact of dairy and beef cattle feedlot runoff on receiving streams. The mathematical expressions used in the model describing runoff quantity and quality were not only a function of single rain or snow precipitation events but also consecutive events prior to the runoff occurrence. The runoff quantity and quality were also a function of feedlot surface. Computer s...

  13. Multichord time-resolved electron temperature measurements by the x-ray absorber-foil method on TFTR

    International Nuclear Information System (INIS)

    Kiraly, J.; Bitter, M.; Efthimion, P.

    1985-09-01

    Absorber foils have been installed in the TFTR X-Ray Imaging System to permit measurement of the electron temperature along 10 to 30 chords spaced at 5-12.5 cm with a time resolution of less than 100 μs. The technique uses the ratio of x-ray fluxes transmitted through two different foils. The ratio depends mainly on electron temperature. Simulations show that strong impurity line radiation can distort this ratio. To correct for these effects, special beryllium-scandium filters are employed to select the line-free region between 2 and 4.5 keV. Other filter pairs allow corrections for Fe L and Ni L line radiation as well as Ti K and Ni K emission. Good accuracy is also obtained with simple beryllium filters, provided that impurity corrections are incorporated in the analysis, taking line intensities from the x-ray pulse-height analysis diagnostic. A description of modeling calculations and a comparison of temperature values from this diagnostic with data from the x-ray pulse height analysis, the electron cyclotron emission, and the Thomson scattering diagnostics are presented. Several applications of the absorber foil electron temperature diagnostic on TFTR are discussed

  14. Multichord time-resolved electron temperature measurements by the x-ray absorber-foil method on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Kiraly, J.; Bitter, M.; Efthimion, P.; von Goeler, S.; Grek, B.; Hill, K.W.; Johnson, D.; McGuire, K.; Sauthoff, N.; Sesnic, S.

    1985-09-01

    Absorber foils have been installed in the TFTR X-Ray Imaging System to permit measurement of the electron temperature along 10 to 30 chords spaced at 5-12.5 cm with a time resolution of less than 100 ..mu..s. The technique uses the ratio of x-ray fluxes transmitted through two different foils. The ratio depends mainly on electron temperature. Simulations show that strong impurity line radiation can distort this ratio. To correct for these effects, special beryllium-scandium filters are employed to select the line-free region between 2 and 4.5 keV. Other filter pairs allow corrections for Fe L and Ni L line radiation as well as Ti K and Ni K emission. Good accuracy is also obtained with simple beryllium filters, provided that impurity corrections are incorporated in the analysis, taking line intensities from the x-ray pulse-height analysis diagnostic. A description of modeling calculations and a comparison of temperature values from this diagnostic with data from the x-ray pulse height analysis, the electron cyclotron emission, and the Thomson scattering diagnostics are presented. Several applications of the absorber foil electron temperature diagnostic on TFTR are discussed.

  15. Phosphorus runoff from turfgrass as affected by phosphorus fertilization and clipping management.

    Science.gov (United States)

    Bierman, Peter M; Horgan, Brian P; Rosen, Carl J; Hollman, Andrew B; Pagliari, Paulo H

    2010-01-01

    Phosphorus enrichment of surface water is a concern in many urban watersheds. A 3-yr study on a silt loam soil with 5% slope and high soil test P (27 mg kg(-1) Bray P1) was conducted to evaluate P fertilization and clipping management effects on P runoff from turfgrass (Poa pratensis L.) under frozen and nonfrozen conditions. Four fertilizer treatments were compared: (i) no fertilizer, (ii) nitrogen (N)+potassium (K)+0xP, (iii) N+K+1xP, and (iv) N+K+3xP. Phosphorus rates were 21.3 and 63.9 kg ha(-1) yr(-1) the first year and 7.1 and 21.3 kg ha(-1) yr(-1) the following 2 yr. Each fertilizer treatment was evaluated with clippings removed or clippings recycled back to the turf. In the first year, P runoff increased with increasing P rate and P losses were greater in runoff from frozen than nonfrozen soil. In year 2, total P runoff from the no fertilizer treatment was greater than from treatments receiving fertilizer. This was because reduced turf quality resulted in greater runoff depth from the no fertilizer treatment. In year 3, total P runoff from frozen soil and cumulative total P runoff increased with increasing P rate. Clipping management was not an important factor in any year, indicating that returning clippings does not significantly increase P runoff from turf. In the presence of N and K, P fertilization did not improve turf growth or quality in any year. Phosphorus runoff can be reduced by not applying P to high testing soils and avoiding fall applications when P is needed.

  16. Role of lattice structure and low temperature resistivity in fast-electron-beam filamentation in carbon

    International Nuclear Information System (INIS)

    Dance, R J; Butler, N M H; Gray, R J; MacLellan, D A; Rusby, D R; Xu, H; Neely, D; McKenna, P; Scott, G G; Robinson, A P L; Zielbauer, B; Bagnoud, V; Desjarlais, M P

    2016-01-01

    The influence of low temperature (eV to tens-of-eV) electrical resistivity on the onset of the filamentation instability in fast-electron transport is investigated in targets comprising of layers of ordered (diamond) and disordered (vitreous) carbon. It is shown experimentally and numerically that the thickness of the disordered carbon layer influences the degree of filamentation of the fast-electron beam. Strong filamentation is produced if the thickness is of the order of 60 μm or greater, for an electron distribution driven by a sub-picosecond, mid-10 20 Wcm −2 laser pulse. It is shown that the position of the vitreous carbon layer relative to the fast-electron source (where the beam current density and background temperature are highest) does not have a strong effect because the resistive filamentation growth rate is high in disordered carbon over a wide range of temperatures up to the Spitzer regime. (paper)

  17. Urban Runoff: National Management Measures

    Science.gov (United States)

    This helps citizens and municipalities in urban areas protect bodies of water from polluted runoff . These scientifically sound techniques are the best practices known today. The guidance helps states to implement their nonpoint source control program.

  18. Translational, rotational, vibrational and electron temperatures of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Ehn, Andreas; Gao, Jinlong

    2017-01-01

    , 0) band was used to simulate the rotational temperature (Tr) of the gliding arc discharge whereas the NO A–X (1, 0) and (0, 1) bands were used to determine its vibrational temperature (Tv). The instantaneous reduced electric field strength E/N was obtained by simultaneously measuring......Translational, rotational, vibrational and electron temperatures of a gliding arc discharge in atmospheric pressure air were experimentally investigated using in situ, non-intrusive optical diagnostic techniques. The gliding arc discharge was driven by a 35 kHz alternating current (AC) power source...... and operated in a glow-type regime. The two-dimensional distribution of the translational temperature (Tt) of the gliding arc discharge was determined using planar laser-induced Rayleigh scattering. The rotational and vibrational temperatures were obtained by simulating the experimental spectra. The OH A–X (0...

  19. Comparative assessment of predictions in ungauged basins – Part 3: Runoff signatures in Austria

    Directory of Open Access Journals (Sweden)

    A. Viglione

    2013-06-01

    Full Text Available This is the third of a three-part paper series through which we assess the performance of runoff predictions in ungauged basins in a comparative way. Whereas the two previous papers by Parajka et al. (2013 and Salinas et al. (2013 assess the regionalisation performance of hydrographs and hydrological extremes on the basis of a comprehensive literature review of thousands of case studies around the world, in this paper we jointly assess prediction performance of a range of runoff signatures for a consistent and rich dataset. Daily runoff time series are predicted for 213 catchments in Austria by a regionalised rainfall–runoff model and by Top-kriging, a geostatistical estimation method that accounts for the river network hierarchy. From the runoff time-series, six runoff signatures are extracted: annual runoff, seasonal runoff, flow duration curves, low flows, high flows and runoff hydrographs. The predictive performance is assessed in terms of the bias, error spread and proportion of unexplained spatial variance of statistical measures of these signatures in cross-validation (blind testing mode. Results of the comparative assessment show that, in Austria, the predictive performance increases with catchment area for both methods and for most signatures, it tends to increase with elevation for the regionalised rainfall–runoff model, while the dependence on climate characteristics is weaker. Annual and seasonal runoff can be predicted more accurately than all other signatures. The spatial variability of high flows in ungauged basins is the most difficult to estimate followed by the low flows. It also turns out that in this data-rich study in Austria, the geostatistical approach (Top-kriging generally outperforms the regionalised rainfall–runoff model.

  20. Temperature dependence of the electronic structure of semiconductors and insulators

    Energy Technology Data Exchange (ETDEWEB)

    Poncé, S., E-mail: samuel.pon@gmail.com; Gillet, Y.; Laflamme Janssen, J.; Gonze, X. [European Theoretical Spectroscopy Facility and Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, bte L07.03.01, B-1348 Louvain-la-neuve (Belgium); Marini, A. [Consiglio Nazionale delle Ricerche (CNR), Via Salaria Km 29.3, CP 10, 00016 Monterotondo Stazione (Italy); Verstraete, M. [European Theoretical Spectroscopy Facility and Physique des matériaux et nanostructures, Université de Liège, Allée du 6 Août 17, B-4000 Liège (Belgium)

    2015-09-14

    The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected in ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory in the adiabatic or non-adiabatic harmonic approximation. After a short description of the recent progresses in this field and a brief overview of the theory, we focus on the issue of phonon wavevector sampling convergence, until now poorly understood. Indeed, the renormalization is obtained numerically through a slowly converging q-point integration. For non-zero Born effective charges, we show that a divergence appears in the electron-phonon matrix elements at q → Γ, leading to a divergence of the adiabatic renormalization at band extrema. This problem is exacerbated by the slow convergence of Born effective charges with electronic wavevector sampling, which leaves residual Born effective charges in ab initio calculations on materials that are physically devoid of such charges. Here, we propose a solution that improves this convergence. However, for materials where Born effective charges are physically non-zero, the divergence of the renormalization indicates a breakdown of the adiabatic harmonic approximation, which we assess here by switching to the non-adiabatic harmonic approximation. Also, we study the convergence behavior of the renormalization and develop reliable extrapolation schemes to obtain the converged results. Finally, the adiabatic and non-adiabatic theories, with corrections for the slow Born effective charge convergence problem (and the associated divergence) are applied to the study of five semiconductors and insulators: α-AlN, β-AlN, BN, diamond, and silicon. For these five materials, we present the zero-point renormalization, temperature dependence, phonon-induced lifetime broadening, and the renormalized electronic band structure.

  1. Low-temperature electron microscopy and electron diffraction study of La/sub 1. 84/Sr/sub 0. 16/CuO/sub 4/

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, Takashi; Omori, Mamoru; Hirabayashi, Makoto; Syono, Yasuhiko

    1987-10-01

    A high-T/sub c/ superconducting compound, La/sub 1.84/Sr/sub 0.16/CuO/sub 4/, has been investigated by electron microscopy and electron diffraction in the range from 10 K to ambient temperature. The tetragonal K/sub 2/NiF/sub 4/-type structure undergoes an orthorhombic distortion below about 130 K. In the low-temperature phase, extra diffraction spots and twin lamellae are observed reversibly on cooling and heating in situ. Based on the observed results, a plausible structure model with orthorhombic distortion is proposed

  2. Electron irradiation effect on the reverse phase transformation temperatures in TiNi shape memory alloy thin films