WorldWideScience

Sample records for models determining water

  1. Determining extreme parameter correlation in ground water models

    DEFF Research Database (Denmark)

    Hill, Mary Cole; Østerby, Ole

    2003-01-01

    In ground water flow system models with hydraulic-head observations but without significant imposed or observed flows, extreme parameter correlation generally exists. As a result, hydraulic conductivity and recharge parameters cannot be uniquely estimated. In complicated problems, such correlation...... correlation coefficients, but it required sensitivities that were one to two significant digits less accurate than those that required using parameter correlation coefficients; and (3) both the SVD and parameter correlation coefficients identified extremely correlated parameters better when the parameters...

  2. Radiative transfer modeling applied to sea water constituent determination. [Gulf of Mexico

    Science.gov (United States)

    Faller, K. H.

    1979-01-01

    Optical radiation from the sea is influenced by pigments dissolved in the water and contained in discrete organisms suspended in the sea, and by pigmented and unpigmented inorganic and organic particles. The problem of extracting the information concerning these pigments and particulates from the optical properties of the sea is addressed and the properties which determine characteristics of the radiation that a remote sensor will detect and measure are considered. The results of the application of the volume scattering function model to the data collected in the Gulf of Mexico and its environs indicate that the size distribution of the concentrations of particles found in the sea can be predicted from measurements of the volume scattering function. Furthermore, with the volume scattering function model and knowledge of the absorption spectra of dissolved pigments, the radiative transfer model can compute a distribution of particle sizes and indices of refraction and concentration of dissolved pigments that give an upwelling light spectrum that closely matches measurements of that spectrum at sea.

  3. Determining TOC in Waters

    Science.gov (United States)

    Kehoe, Thomas J.

    1977-01-01

    The instrumental method for detecting total organic carbon (TOC) in water samples is detailed. The method's limitations are discussed and certain precautions that must be taken are emphasized. The subject of TOC versus COD and BOD is investigated and TOC is determined to be a valid indication of biological demand. (BT)

  4. Applicability of CFD Modelling in Determining Accurate Weir Discharge: Water Level Relationships

    NARCIS (Netherlands)

    Rombouts, P.M.M.; Tralli, A.; Langeveld, J.G.; Verhaart, F.; Clemens, F.H.L.R.

    2014-01-01

    Being able to accurately determine weir discharges is of key importance in urban water management. The most common method is performing a level measurement and calculating the discharge using the standard weir equation. Since this equation is only valid in certain conditions, this can lead to large

  5. A modelling approach to determine the origin of urban ground water.

    Science.gov (United States)

    Trowsdale, Sam A; Lerner, David N

    2007-04-01

    A simple modelling approach was developed to link patterns of urban land-use with ground water flow and chemistry in three dimensions and was applied to characterize the origin of recharge in the aquifer beneath the old industrial city of Nottingham, UK. The approach involved dividing land uses into types, and times into periods, and assigning the recharge from each an individual tracer-solute with a unit concentration. The computer code MT3DMS was used to track the multiple tracer-solutes in transient, three-dimensional simulations of the important urban aquifer. A depth-specific hydrochemical dataset collected in parallel supported the model predictions. At depth under the industrial area studied, a large component of ground water originated of older agricultural origin, with relatively low nitrate concentrations. Shallower ground water originated mainly from residential and industrial areas, with higher nitrate concentrations probably arising from leaking sewers and contaminated land. The results highlighted the spectrum of ground water from different origins that amalgamate even at short well screens in a non-pumped borehole and remind us that the non-point-source pollution of ground water from anthropogenic activities will involve more years of slow degradation of quality.

  6. Modelling of the Water Absorption Kinetics and Determination of the Water Diffusion Coefficient in the Pith of Raffia vinifera of Bandjoun, Cameroon

    Directory of Open Access Journals (Sweden)

    E. Tiaya Mbou

    2017-01-01

    Full Text Available The present work focuses on the study of the water absorption phenomenon through the pith of Raffia vinifera along the stem. The water absorption kinetics was studied experimentally by the gravimetric method with the discontinuous control of the sampling mass at temperature of 30°C. The samples of 70 mm × 8 mm × 4 mm were taken from twelve sampling zones of the stem of Raffia vinifera. The result shows that the percentage of water absorption of the pith of Raffia vinifera increases from the periphery to the center in the radial position and from the base to the leaves in the longitudinal position. Fick’s second law was adopted for the study of the water diffusion. Eleven models were tested for the modelling of the water absorption kinetics and the model of Sikame Tagne (2014 is the optimal model. The diffusion coefficients of two stages were determined by the solution of the Fick equation in the twelve sampling zones described by Sikame Tagne et al. (2014. The diffusion coefficients decreased from the center to the periphery in the radial position and from the base to the leaves in the longitudinal position.

  7. Determinants of Household Water Conservation Retrofit Activity: A Discrete Choice Model Using Survey Data

    Science.gov (United States)

    Cameron, T. A.; Wright, M. B.

    1990-02-01

    Economic analyses of residential water demand have typically concentrated on price and income elasticities. In the short run a substantial change in water prices might induce only small changes in consumption levels. As time passes, however, households will have the opportunity to "retrofit" existing water-using equipment to make it less water-intensive. This produces medium- to long-run demand elasticities that are higher than short-run studies suggest. We examine responses to water conservation questions appearing on the Los Angeles Department of Water and Power's 1983 residential energy survey. We find that households' decisions to install shower retrofit devices are influenced by the potential to save money on water heating bills. We attribute toilet retrofit decisions more to noneconomic factors which might be characterized as "general conservation mindedness." The endogeneity of these retrofit decisions casts some doubt on the results of studies of individual households that treat voluntary retrofits as exogenous.

  8. Using Hyperspectral Remote Sensing Models to Determine Phytoplankton Density in the Coastal Waters of Long Bay, South Carolina

    Science.gov (United States)

    Harrington, J. E.; Ali, K.

    2013-12-01

    as an index for the estimation of phytoplankton density. Efficiency of the algorithms were evaluated through a least squares regression and residual analysis. Results show that for prediction models of chlorophyll a concentrations, the Oc4v4 by Reilly et al (2000), two -band blue-green empirical algorithm yielded coefficients of determination as high as 0.64 with RMSE=0.29μg/l for an aggregated dataset (n=62, Premote sensing in accounting for the chlorophyll a variability in the turbid waters of Long Bay, SC.

  9. Economic Time Series Modeling to Determine the Feasibility of Incorporating Drinking Water Treatment in Water Quality Trading

    Science.gov (United States)

    The critical steps required to evaluating the feasiblity of establishing a water quality trading market in a testbed watershed is described. Focus is given toward describing the problem of thin markets as a specifi barrier to successful trading. Economic theory for considering an...

  10. Economic Time Series Modeling to Determine the Feasibility of Incorporating Drinking Water Treatment in Water Quality Trading

    Science.gov (United States)

    The critical steps required to evaluating the feasiblity of establishing a water quality trading market in a testbed watershed is described. Focus is given toward describing the problem of thin markets as a specifi barrier to successful trading. Economic theory for considering an...

  11. Determining Potential Sites for Runoff Water Harvesting using Remote Sensing and Geographic Information Systems-Based Modeling in Sinai

    Directory of Open Access Journals (Sweden)

    Hossam H. Elewa

    2012-01-01

    Full Text Available Problem statement: Sinai is increasingly suffering from an overwhelming water crisis. Runoff Water Harvesting (RWH could be a solution for this problem. The determined promising drainage basins for RWH could be used by the decision makers to propose appropriate controlling systems to overcome the problem of water scarcity and for implementing runoff farming and rain-fed agriculture. Approach: Remote sensing, geographic information systems, watershed modeling system were integrated to extract a multi-criteria-decision support system of nine thematic layers, namely; volume of annual flood, lineaments frequency density, drainage frequency density, maximum flow distance, basin area, basin slope, basin length, average overland flow distance and soil infiltration. These criteria were used for conducting a Weighted Spatial Probability Modeling (WSPM to determine the potential areas for the RWH. The potential runoff available for harvesting was estimated by applying Finkel-SCS rainfall-runoff methods. Results: The WSPM classified Sinai into four classes that graded from high (3,201-6,695 km2, moderate (35,923-35,896 km2, low (13,185-16,652 km2, very low (1.38-5.57 km2 for RWH. Promising watersheds like those of Abu Taryfya, Hamma El Hassana, Gerafi, Watir, Geraia, Heridien, Sidri, Feiran and Alaawag, are categorized as high-moderate RWH potential basins. Conclusion: These basins could be investigated in detail with larger scale to determine the appropriate locations for implementing the RWH structures and techniques. Implementing systems and techniques of RWH in the potential watersheds could open new opportunities for sustainable development in the area.

  12. Modeling sampling strategies for determination of zooplankton abundance in ballast water.

    Science.gov (United States)

    Hernandez, Marco R; Johansson, Mattias L; Xiao, Yanyu; Lewis, Mark A; MacIsaac, Hugh J

    2017-02-15

    Ballast water has been a major source of non-indigenous species introductions. The International Maritime Organization has proposed performance standard that will establish an upper limit for viable organisms in discharged ballast. Here we test different sampling efforts for zooplankton in ballast water on a commercial vessel. We fit different probability density functions to find the most representative and evaluated sampling efforts necessary to achieve error rates (α, β) of sample volumes. To estimate error rates, we performed simulations which drew from 1 to 30 replicates of each volume (0.10-3.00m(3)) for mean densities ranging between 1 and 20 organisms m(-3). Fieldwork and simulations suggested that >0.5m(3) samples had the best accuracy and precision, and that the Poisson distribution fit these communities best. This study provides the first field test of a sampling strategy to assess compliance with the future IMO standard for large vessels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Computational Models to Determine Transport and Hydrolysis Rate Parameters of Contaminants in a Water Distribution System

    Science.gov (United States)

    2008-12-01

    opposite to the fluoride leaving group through an SN2 -type reaction . Competition exists between a breaking of the P-S bond and a breaking of the P- OEt...model (PCM) in Gaussian03 to predict reaction rates of hydrolysis. 1. INTRODUCTION In previous research, empirical methods showed that uptake of... reaction . Verification that a transi- tion state was obtained in the degradation pathway was ob- tained by carefully tracing the reaction path in both direc

  14. A Simple Model to Determine the Trends of Electric Field Enhanced Water Dissociation in a Bipolar Membrane

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.

  15. Determination of rational design parameters of a multi-stage solar water desalination still using transient mathematical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Shatat, M.I.M.; Mahkamov, K. [School of Engineering, Durham University, South Road, Durham, DH1 3LE (United Kingdom)

    2010-01-15

    The paper describes the experimental investigations of the performance of a multi-stage water desalination still connected to a heat pipe evacuated tube solar collector with aperture area of 1.7 m{sup 2}. The multi-stage solar still water desalination system was designed to recover latent heat from evaporation and condensation processes in four stages. The variation in the solar radiation during a typical mid-summer day in the Middle East region was simulated on the test rig using an array of 110 halogen floodlights covering the area of the collector. The results of tests demonstrate that the system produces about 9 kg of fresh water per day and has a solar collector efficiency of about 68%. However, the overall efficiency of the laboratory test rig at this stage of the investigations was found to be at the level of 33% due to excessive heat losses in the system. The analysis of the distilled water showed that its quality was within the World Health Organization guidelines. The still's operation was numerically simulated by employing a mathematical model based on a system of ordinary energy and mass conservation differential equations written for each stage of the still. A computer program was developed for transient simulations of the evaporation and condensation processes inside the multi-stage still. Experimental results obtained and theoretical predictions were found to be in good agreement. The results on the determination of rational design dimensions and number of stages of the still for a given aperture of the solar collector are also presented in this work. (author)

  16. EPANET water quality model

    Energy Technology Data Exchange (ETDEWEB)

    Rossman, L.A.

    1993-01-01

    EPANET represents a third generation of water quality modeling software developed by the U.S. EPA's Drinking Water Research Division, offering significant advances in the state of the art for network water quality analysis. EPANET performs extended period simulation of hydraulic and water quality behavior within water distribution systems. In addition to substance concentration, water age and source tracing can also be simulated. EPANET includes a full featured hydraulic simulation model that can handle various types of pumps, valves, and their control rules. The water quality module is equipped to handle constituent reactions within the bulk pipe flow and at the pipe wall. It also features an efficient computational scheme that automatically determines optimal time steps and pipe segmentation for accurate tracking of material transport over time. EPANET is currently being used in the US to study such issues as loss of chlorine residual, source blending and trihalomethane (THM) formation, how altered tank operation affects water age, and total dissolved solids (TDS) control for an irrigation network.

  17. Determination of Cr in water solution by laser-induced breakdown spectroscopy with different univariate calibration models

    Science.gov (United States)

    Huang, Lin; Yao, Mingyin; Xu, Yuan; Liu, Muhua

    2013-04-01

    In order to prove the feasibility of laser-induced breakdown spectroscopy (LIBS) in measuring toxic metals Cr in water solution, a series of potassium bichromate standard solutions were prepared in the lab. The characteristic line intensity of Cromium (Cr) element at 357.87, 359.35, 360.53, 425.43, 427.48, and 428.97 nm was taken to build up the correlation with concentration. The indexes of relative standard deviation, intercept, slope, R 2 (coefficient of determination), and root mean square error of calibration were selected to verify the precision and accuracy of models. The comprehensive results showed that the 425.43 nm line had better superiority than other lines. And the detection limit of 6 ug/ml and repeatability of 3 % are reported. To improve the model accuracy further, the intensity ratio of single 425.43 nm line to the whole spectrum was extracted. And a linear relationship between the intensity ratio and the element Cr concentration was constructed. The results demonstrated the intensity ratio calibration had better accuracy than single line calibration, especially after smoothing. To verify the accuracy of prediction, the 100 ug/ml concentration sample was used as prediction sample. The relative error values are 13.2, 11.7, and 10.8 % for single line calibration, intensity ratio calibration with raw data, and by use of smooth processing data, respectively. The results further indicated that the intensity ratio calibration improved the accuracy of measurement than single line calibration. It is worth mentioning that the application of LIBS aiming the direct analysis of heavy metals in water is a great challenge that still needs efforts for its development and validation.

  18. Determining the terrain characteristics related to the surface expression of subsurface water pressurization in permafrost landscapes using susceptibility modelling

    Science.gov (United States)

    Holloway, Jean E.; Rudy, Ashley C. A.; Lamoureux, Scott F.; Treitz, Paul M.

    2017-06-01

    Warming of the Arctic in recent years has led to changes in the active layer and uppermost permafrost. In particular, thick active layer formation results in more frequent thaw of the ice-rich transient layer. This addition of moisture, as well as infiltration from late season precipitation, results in high pore-water pressures (PWPs) at the base of the active layer and can potentially result in landscape degradation. To predict areas that have the potential for subsurface pressurization, we use susceptibility maps generated using a generalized additive model (GAM). As model response variables, we used active layer detachments (ALDs) and mud ejections (MEs), both formed by high PWP conditions at the Cape Bounty Arctic Watershed Observatory, Melville Island, Canada. As explanatory variables, we used the terrain characteristics elevation, slope, distance to water, topographic position index (TPI), potential incoming solar radiation (PISR), distance to water, normalized difference vegetation index (NDVI; ME model only), geology, and topographic wetness index (TWI). ALDs and MEs were accurately modelled in terms of susceptibility to disturbance across the study area. The susceptibility models demonstrate that ALDs are most probable on hill slopes with gradual to steep slopes and relatively low PISR, whereas MEs are associated with higher elevation areas, lower slope angles, and areas relatively far from water. Based on these results, this method identifies areas that may be sensitive to high PWPs and helps improve our understanding of geomorphic sensitivity to permafrost degradation.

  19. A model to determine the lake nutrient standards for drinking water sources in Yunnan-Guizhou Plateau Ecoregion, China

    Institute of Scientific and Technical Information of China (English)

    Danfeng Ji; Beidou Xi; Jing Su; Shouliang Huo; Li He; Hongliang Liu; Queping Yang

    2013-01-01

    Lake eutrophication (LE) has become an increasingly severe environmental problem recently.However,there has been no nutrient standard established for LE control in many developing countries such as China.This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion (Yungui Ecoregion),China.The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus (TP) (total effect =-0.43),and chlorophyll a (Chl-a) is recommended as the second important indicator (total effect =-0.41).The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria (based on the reference conditions and the current environmental quality standards for surface water).It is found that these candidate criteria cannot satisfy the designated 100% use-attainment.To achieve the short-term target (85% attainment of the designated use),TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 tg/L,respectively.When used as a long-term target (90% or greater attainment of the designated use),the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 μg/L,respectively.

  20. Determination of fractional energy loss of waves in nearshore waters using an improved high-order Boussinesq-type model

    Institute of Scientific and Technical Information of China (English)

    HE Hailun; SONG Jinbao; Patrick J. Lynett; LI Shuang

    2009-01-01

    Fractional energy losses of waves due to wave breaking when passing over a submerged bar are studied systematically using a modified numerical code that is based on the high-order Boussinesq-type equations. The model is first tested by the additional experimental data, and the model's capability of simulating the wave transformation over both gentle slope and steep slope is demonstrated. Then, the model's breaking index is replaced and tested. The new breaking index, which is optimized from the several breaking indices, is not sensitive to the spatial grid length and includes the bottom slopes. Numerical tests show that the modified model with the new breaking index is more stable and efficient for the shallow-water wave breaking. Finally, the modified model is used to study the fractional energy losses for the regular waves propagating and breaking over a submerged bar. Our results have revealed that how the nonlinearity and the dispersion of the incident waves as well as the dimensionless bar height (normalized by water depth) dominate the fractional energy losses. It is also found that the bar slope (limited to gentle slopes that less than 1:10) and the dimensionless bar length (normalized by incident wave length) have negligible effects on the fractional energy losses.

  1. DETERMINATION OF ACTIVATED SLUDGE MODEL ASDM PARAMETERS FOR WASTE WATER TREATMENT PLANT OPERATING IN THE SEQUENTIAL–FLOW TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Dariusz Zdebik

    2015-01-01

    Full Text Available This paper presents a method for calibration of activated sludge model with the use of computer program BioWin. Computer scheme has been developed on the basis of waste water treatment plant operating in the sequential – flow technology. For calibration of the activated sludge model data of influent and treated effluent from the existing object were used. As a result of conducted analysis was a change in biokinetic model and kinetic parameters parameters of wastewater treatment facilities. The presented method of study of the selected parameters impact on the activated sludge biokinetic model (including autotrophs maximum growth rate, the share of organic slurry in suspension general operational, efficiency secondary settling tanks can be used for conducting simulation studies of other treatment plants.

  2. A modeling approach to determine the impacts of land use and climate change scenarios on the water flux of the upper Mara River

    Directory of Open Access Journals (Sweden)

    L. M. Mango

    2010-08-01

    Full Text Available With the flow of the Mara River becoming increasingly erratic especially in the upper reaches, attention has been directed to land use change as the major cause of this problem. The semi-distributed hydrological model Soil and Water Assessment Tool (SWAT and Landsat imagery were utilized in the upper Mara River Basin in order to 1 map existing field scale land use practices in order to determine their impact 2 determine the impacts of land use change on water flux; and 3 determine the impacts of rainfall (0%, ±10% and ±20% and air temperature variations (0% and +5% based on the Intergovernmental Panel on Climate Change projections on the water flux of the upper Mara River.

    This study found that the different scenarios impacted on the water balance components differently. Land use changes resulted in a slightly more erratic discharge while rainfall and air temperature changes had a more predictable impact on the discharge and water balance components. These findings demonstrate that the model results show the flow was more sensitive to the rainfall changes than land use changes. It was also shown that land use changes can reduce dry season flow which is the most important problem in the basin. The model shows also deforestation in the Mau Forest increased the peak flows which can also lead to high sediment loading in the Mara River. The effect of the land use and climate change scenarios on the sediment and water quality of the river needs a thorough understanding of the sediment transport processes in addition to observed sediment and water quality data for validation of modeling results.

  3. A modeling approach to determine the impacts of land use and climate change scenarios on the water flux of the upper Mara River

    Science.gov (United States)

    Mango, L. M.; Melesse, A. M.; McClain, M. E.; Gann, D.; Setegn, S. G.

    2010-08-01

    With the flow of the Mara River becoming increasingly erratic especially in the upper reaches, attention has been directed to land use change as the major cause of this problem. The semi-distributed hydrological model Soil and Water Assessment Tool (SWAT) and Landsat imagery were utilized in the upper Mara River Basin in order to 1) map existing field scale land use practices in order to determine their impact 2) determine the impacts of land use change on water flux; and 3) determine the impacts of rainfall (0%, ±10% and ±20%) and air temperature variations (0% and +5%) based on the Intergovernmental Panel on Climate Change projections on the water flux of the upper Mara River. This study found that the different scenarios impacted on the water balance components differently. Land use changes resulted in a slightly more erratic discharge while rainfall and air temperature changes had a more predictable impact on the discharge and water balance components. These findings demonstrate that the model results show the flow was more sensitive to the rainfall changes than land use changes. It was also shown that land use changes can reduce dry season flow which is the most important problem in the basin. The model shows also deforestation in the Mau Forest increased the peak flows which can also lead to high sediment loading in the Mara River. The effect of the land use and climate change scenarios on the sediment and water quality of the river needs a thorough understanding of the sediment transport processes in addition to observed sediment and water quality data for validation of modeling results.

  4. Iron speciation in soft-water lakes and soils as determined by EXAFS spectroscopy and geochemical modelling

    Science.gov (United States)

    Sjöstedt, Carin; Persson, Ingmar; Hesterberg, Dean; Kleja, Dan Berggren; Borg, Hans; Gustafsson, Jon Petter

    2013-03-01

    Complexation of iron by organic matter can potentially compete with toxic metals for binding sites. Iron(III) forms both monomeric and di/trimeric complexes with fulvic and humic acids, but the nature and extent of complexation with natural organic matter samples from soft-water lakes has not been extensively studied. The aim of this study was to determine the coordination of iron in complexes with organic matter in two soft-water lakes and in the surrounding Oe soil horizons. Iron K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy was performed on particles and large colloids (>0.45 μm) collected by in-line pre-filtration, and on smaller colloids isolated both on an AGMP-1 anion-exchange column and by concentration using 1000 Da ultrafiltration. The results showed that iron(III) was mainly present in monomeric complexes with organic matter, both in the lake water smaller colloids and in the soil samples. Evidence for iron(III) (hydr)oxides was found for the lake particles, in the ultrafiltration retentates, and in some of the soils. Overall, the results suggest that complexation of iron(III) to organic matter prevents hydrolysis into polymeric forms. Strong complexation of iron(III) would lead to competition with other metals for organic-matter binding sites.

  5. Input determination for neural network models in water resources applications. Part 2. Case study: forecasting salinity in a river

    Science.gov (United States)

    Bowden, Gavin J.; Maier, Holger R.; Dandy, Graeme C.

    2005-01-01

    This paper is the second of a two-part series in this issue that presents a methodology for determining an appropriate set of model inputs for artificial neural network (ANN) models in hydrologic applications. The first paper presented two input determination methods. The first method utilises a measure of dependence known as the partial mutual information (PMI) criterion to select significant model inputs. The second method utilises a self-organising map (SOM) to remove redundant input variables, and a hybrid genetic algorithm (GA) and general regression neural network (GRNN) to select the inputs that have a significant influence on the model's forecast. In the first paper, both methods were applied to synthetic data sets and were shown to lead to a set of appropriate ANN model inputs. To verify the proposed techniques, it is important that they are applied to a real-world case study. In this paper, the PMI algorithm and the SOM-GAGRNN are used to find suitable inputs to an ANN model for forecasting salinity in the River Murray at Murray Bridge, South Australia. The proposed methods are also compared with two methods used in previous studies, for the same case study. The two proposed methods were found to lead to more parsimonious models with a lower forecasting error than the models developed using the methods from previous studies. To verify the robustness of each of the ANNs developed using the proposed methodology, a real-time forecasting simulation was conducted. This validation data set consisted of independent data from a six-year period from 1992 to 1998. The ANN developed using the inputs identified by the stepwise PMI algorithm was found to be the most robust for this validation set. The PMI scores obtained using the stepwise PMI algorithm revealed useful information about the order of importance of each significant input.

  6. Determining lake surface water temperatures (LSWTs worldwide using a tuned 1-dimensional lake model (FLake, v1

    Directory of Open Access Journals (Sweden)

    A. Layden

    2015-10-01

    Full Text Available FLake, a 1-dimensional freshwater lake model, is tuned for 244 globally distributed large lakes using lake surface water temperatures (LSWTs derived from Along-Track Scanning Radiometers (ATSRs. The model, tuned using only 3 lake properties; lake depth, albedo (snow and ice and light extinction co-efficient, substantially improves the measured biases in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes. The daily mean absolute differences (MAD and the spread of differences (±2 standard deviations across the trial seasonally ice covered lakes (lakes with a lake-mean LSWT remaining below 1 °C for part of the annual cycle is reduced from 3.01± 2.25 °C (pre-tuning to 0.84 ± 0.51 °C (post-tuning. For non-seasonally ice-covered trial lakes (lakes with a lake-mean LSWT remaining above 1 °C throughout its annual cycle, the average daily mean absolute difference (MAD is reduced from 3.55 ± 3.20 °C to 0.96 ± 0.63 °C. The post tuning results for the trial lakes (35 lakes are highly representative of the post tuning results of the 244 lakes. The sensitivity of the summer LSWTs of deeper lakes to changes in the timing of ice-off is demonstrated. The modelled summer LSWT response to changes in ice-off timing is found to be strongly affected by lake depth and latitude, explaining 0.50 (R2adj, p = 0.001 of the inter-lake variance in summer LSWTs. Lake depth alone explains 0.35 (p =0.003 of the variance. The tuning approach undertaken in this study, overcomes the obstacle of the lack of available lake characteristic information (snow and ice albedo and light extinction co-efficient for individual lakes. Furthermore, the tuned values for lake depth, snow and ice albedo and light extinction co-efficient for the 244 lakes provide guidance for improving LSWTs modelling in FLake.

  7. Comparison of MRI techniques and modelling with R-SWMS for determining solute distribution patterns and root water uptake of a white lupine plant (Lupinus Albus L.).

    Science.gov (United States)

    Koch, Axelle; Schröder, Natalie; Pohlmeier, Andreas; Garré, Sarah; Vanderborght, Jan; Javaux, Mathieu

    2017-04-01

    Measuring water extraction by plant would allow us to better understand root water uptake processes and how soil and plant properties affect them. Yet, direct measurement of root water uptake is still challenging and determining its distribution requires coupling experimentation and modelling. In this study, we investigated how the 3D monitoring of a tracer movement in a sand container with a lupine plant could inform us about root water uptake process. A sand column (10 cm height, 5 cm inner diameter) planted with an 18-day-old white lupine was subject to a tracer experiment with a chemically inert tracer (1 mmol/L Gd-DTPA2-) applied for 6 days. Then the tracer and water fluxes were stopped. The plume was monitored in 3-D for 7 days by Magnetic Resonance Imaging (Haber-Pohlmeier et al, unp). In addition the breakthrough curve at the outlet was also measured. We used a biophysical 3-D soil-plant model: R-SWMS (Javaux et al, 2008) to extract information from this experiment. First, we ran a virtual experiment to check the assumption that Gd concentration increase around roots is proportional to the extracted soil water during the same period. We also investigated whether this type of experiment helps discriminate different root hydraulic properties with a sensitivity analysis. Then, we compared the experimental and simulated Gd concentration patterns. A preliminary (qualitative) assessment showed that measured Gd distribution patterns were better represented by the model at day 7, where the main driver of the concentration distribution was root and not soil heterogeneity (which is not taken into account in the model). The main spatial and temporal features of the transport where adequately reproduced by the model in particular during the last day. The distribution of the tracer was shown to be sensitive to the root hydraulic properties. To conclude, information about root water uptake distributions and so about root hydraulic properties could be deduced from Gd

  8. Radon determination in ground water

    Energy Technology Data Exchange (ETDEWEB)

    Segovia A, N.; Bulbulian G, S

    1991-08-15

    Studies on natural radioactivity in ground water were started in Mexico in San Luis Potosi state followed by samplings from deep wells and springs in the states of Mexico and Michoacan. The samples were analyzed for solubilized and {sup 226} Ra- supported {sup 222} Rn. Some of them were also studied for {sup 234} U/ {sup 238} U activity ratio. In this paper we discuss the activities obtained and their relationship with the geologic characteristics of the studied zones. (Author)

  9. WATER DIVERSION MODEL

    Energy Technology Data Exchange (ETDEWEB)

    J.B. Case

    1999-12-21

    The distribution of seepage in the proposed repository will be highly variable due in part to variations in the spatial distribution of percolations. The performance of the drip shield and the backfill system may divert the water flux around the waste packages to the invert. Diversion will occur along the drift surface, within the backfill, at the drip shield, and at the Waste Package (WP) surface, even after the drip shield and WP have been breached by corrosion. The purpose and objective of this Analysis and Modeling Report (AMR) are to develop a conceptual model and constitutive properties for bounding the volume and rate of seepage water that flows around the drip shield (CRWMS M&O 1999c). This analysis model is to be compatible with the selected repository conceptual design (Wilkins and Heath, 1999) and will be used to evaluate the performance of the Engineered Barrier System (EBS), and to provide input to the EBS Water Distribution and Removal Model. This model supports the Engineered Barrier System (EBS) postclosure performance assessment for the Site Recommendation (SR). This document characterizes the hydrological constitutive properties of the backfill and invert materials (Section 6.2) and a third material that represents a mixture of the two. These include the Overton Sand which is selected as a backfill (Section 5.2), crushed tuff which is selected as the invert (Section 5.1), and a combined material (Sections 5.9 and 5.10) which has retention and hydraulic conductivity properties intermediate to the selected materials for the backfill and the invert. The properties include the grain size distribution, the dry bulk density and porosity, the moisture retention, the intrinsic permeability, the relative permeability, and the material thermal properties. The van Genuchten relationships with curve fit parameters are used to define the basic retention relationship of moisture potential to volumetric moisture content, and the basic relationship of unsaturated

  10. Stream Water Quality Model

    Data.gov (United States)

    U.S. Environmental Protection Agency — QUAL2K (or Q2K) is a river and stream water quality model that is intended to represent a modernized version of the QUAL2E (or Q2E) model (Brown and Barnwell 1987).

  11. Modelling of Water Turbidity Parameters in a Water Treatment Plant

    Directory of Open Access Journals (Sweden)

    A. S. KOVO

    2005-01-01

    Full Text Available The high cost of chemical analysis of water has necessitated various researches into finding alternative method of determining portable water quality. This paper is aimed at modelling the turbidity value as a water quality parameter. Mathematical models for turbidity removal were developed based on the relationships between water turbidity and other water criteria. Results showed that the turbidity of water is the cumulative effect of the individual parameters/factors affecting the system. A model equation for the evaluation and prediction of a clarifier’s performance was developed:Model: T = T0(-1.36729 + 0.037101∙10λpH + 0.048928t + 0.00741387∙alkThe developed model will aid the predictive assessment of water treatment plant performance. The limitations of the models are as a result of insufficient variable considered during the conceptualization.

  12. Methods for determining actual soil water repellence

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.; Oostindie, K.; Moore, D.; Wesseling, J.G.

    2009-01-01

    In this paper we describe a simple and quick method for determining the presence of water repellency in a soil by using a small core sampler (1.5 cm in diameter, 25 cm long) and applying the water drop penetration time (WDPT) test at different depths on the sandy soil cores. Obtained results provide

  13. CREDIT RISK. DETERMINATION MODELS

    Directory of Open Access Journals (Sweden)

    MIHAELA GRUIESCU

    2012-01-01

    Full Text Available The internationalization of financial flows and banking and the rapid development of markets have changed the financial sector, causing him to respond with force and imagination. Under these conditions, the concerns of financial and banking institutions, rating institutions are increasingly turning to find the best solutions to hedge risks and maximize profits. This paper aims to present a number of advantages, but also limits the Merton model, the first structural model for modeling credit risk. Also, some are extensions of the model, some empirical research and performance known, others such as state-dependent models (SDM, which together with the liquidation process models (LPM, are two recent efforts in the structural models, show different phenomena in real life.

  14. Determining alpha-tocopherol distributions between the oil, water, and interfacial regions of macroemulsions: novel applications of electroanalytical chemistry and the pseudophase kinetic model.

    Science.gov (United States)

    Gunaseelan, K; Romsted, Laurence S; Gallego, Maria-Jose Pastoriza; González-Romero, Elisa; Bravo-Díaz, Carlos

    2006-11-16

    The assumptions of the pseudophase model for chemical reactivity in homogeneous microemulsions are used to determine the distribution of alpha-tocopherol (TOC) in macroemulsions from changes in the observed rate constant (k(obs)) for reaction between 4-hexadecylarenediazonium ion (16-ArN2+) probe and TOC with increasing surfactant concentration. Two partition constants are needed to describe the distribution of TOC or other antioxidant (AO) or polar uncharged molecule between the oil and interfacial (P(O)(I)) and the water and interfacial (P(W)(I)) regions of stirred fluid emulsions. The observed rate constants are measured electrochemically. Here we report values of P(O)(I) and P(W)(I) for the distribution of TOC in octane/acidic water/C12E6 (hexaethylene glycol monododecyl ether) and octane/acidic water/C12E4 (Brij 30, tetraethylene glycol dodecyl ether) emulsions obtained by fitting two kinetic data sets with an equation based on the pseudophase model and solving two equations in two unknowns. The partition constants were used to estimate the %TOC in each region of the emulsions. In 1:1 oil:water C12E6 emulsions, at 2% volume fraction of C12E6, 73% of TOC is in the interfacial region, 26% in the octane and about 1% in the water. The distributions of TOC in C12E4 emulsions are similar. The combined electrochemical-pseudophase model approach is applicable to any AO or other compound that reacts with 16-ArN2+. The second-order rate constant, k(I), for reaction in the interfacial region of the emulsions is also estimated from the kinetic data and is about the same for both surfactants (k(I) approximately 0.1-0.2 M(-1)s(-1)) showing that the medium properties of the interfacial regions of C12E6 and C12E4 emulsions are similar. Comparison of these rate constants for a variety of AOs may provide a scale of AO efficiency that is independent of AO distribution between the oil, interfacial and aqueous regions of emulsions.

  15. A method to determine plant water source using transpired water

    Directory of Open Access Journals (Sweden)

    L. B. Menchaca

    2007-04-01

    Full Text Available A method to determine the stable isotope ratio of a plant's water source using the plant's transpired water is proposed as an alternative to standard xylem extraction methods. The method consists of periodically sampling transpired waters from shoots or leaves enclosed in sealed, transparent bags which create a saturated environment, preclude further evaporation and allow the progressive mixing of evaporated transpired water and un-evaporated xylem water. The method was applied on trees and shrubs coexisting in a non-irrigated area where stable isotope ratios of local environmental waters are well characterized. The results show Eucalyptus globulus (tree and Genista monspessulana (shrub using water sources of different isotopic ratios congruent with groundwater and soil water respectively. In addition, tritium concentrations indicate that pine trees (Pinus sylvestris switch water source from soil water in the winter to groundwater in the summer. The method proposed is particularly useful in remote or protected areas and in large scale studies related to water management, environmental compliance and surveillance, because it eliminates the need for destructive sampling and greatly reduces costs associated with laboratory extraction of xylem waters from plant tissues for isotopic analyses.

  16. Multi-criteria decision making development of ion chromatographic method for determination of inorganic anions in oilfield waters based on artificial neural networks retention model.

    Science.gov (United States)

    Stefanović, Stefica Cerjan; Bolanča, Tomislav; Luša, Melita; Ukić, Sime; Rogošić, Marko

    2012-02-24

    This paper describes the development of ad hoc methodology for determination of inorganic anions in oilfield water, since their composition often significantly differs from the average (concentration of components and/or matrix). Therefore, fast and reliable method development has to be performed in order to ensure the monitoring of desired properties under new conditions. The method development was based on computer assisted multi-criteria decision making strategy. The used criteria were: maximal value of objective functions used, maximal robustness of the separation method, minimal analysis time, and maximal retention distance between two nearest components. Artificial neural networks were used for modeling of anion retention. The reliability of developed method was extensively tested by the validation of performance characteristics. Based on validation results, the developed method shows satisfactory performance characteristics, proving the successful application of computer assisted methodology in the described case study.

  17. Accelerated shallow water modeling

    Science.gov (United States)

    Gandham, Rajesh; Medina, David; Warburton, Timothy

    2015-04-01

    ln this talk we will describe our ongoing developments in accelerated numerical methods for modeling tsunamis, and oceanic fluid flows using two dimensional shallow water model and/or three dimensional incompressible Navier Stokes model discretized with high order discontinuous Galerkin methods. High order discontinuous Galerkin methods can be computationally demanding, requiring extensive computational time to simulate real time events on traditional CPU architectures. However, recent advances in computing architectures and hardware aware algorithms make it possible to reduce simulation time and provide accurate predictions in a timely manner. Hence we tailor these algorithms to take advantage of single instruction multiple data (SIMD) architecture that is seen in modern many core compute devices such as GPUs. We will discuss our unified and extensive many-core programming library OCCA that alleviates the need to completely re-design the solvers to keep up with constantly evolving parallel programming models and hardware architectures. We will present performance results for the flow simulations demonstrating performance leveraging multiple different multi-threading APIs on GPU and CPU targets.

  18. Evaluating bio-optical models to determine chlorophyll a from hyper spectral data in the turbid coastal waters of South Carolina

    Science.gov (United States)

    Hames, J. B.; Ali, K.

    2013-12-01

    Millions of people visit the beaches of South Carolina every year and the increasing utilization of the coastal waters is leading to the deterioration of water quality and the marine ecosystem. Ecological stress on these environments is reflected by the increase in the frequency and severity of Harmful Algal Blooms (HABs). This was evident during recent summer seasons particularly in the shallow nearshore waters of Long Bay, South Carolina, an open coast embayment on the South Atlantic Bight. These aspects threaten human and marine life. The early detection of HABs in the coastal waters requires more efficient and accurate monitoring tools. Remote sensing provides synoptic view of the entire Long Bay waters at high temporal coverage and allows resource managers to effectively map and monitor algal bloom development, near real time. Various remote sensing (RS) algorithms have been developed but were mostly calibrated to low resolution global data and or other specific sites. In the summer of 2013, a suite of measurements and water samples were collected from 15 locations along the nearshore waters of Long Bay using the Grice Laboratory R/V. In this study, we evaluate the efficiency of 10 bio-optical blue-green and NIR-red based RS models applied to GER 1500 hyper spectral reflectance data to predict chlorophyll a, a proxy for phytoplankton density, in the Long Bay waters of SC. Efficiency of the algorithms performance in the study site were tested through a least squares regression and residual analysis. Results show that among the selected suite of algorithms the blue green models by Darecki and Stramski (2004) produced R2 of 0.68 with RMSE=0.39μg/l, Oc4v4 model by O'Reilly et al. (2000) gave R2 of 0.62 with RMSE=0.73ug/l, and the Oc2v4 also by O'Reilly et al (2000) gave R2 of 0.69 with RMSE=0.65. Among the NIR-red models, Moses et al (2009) two-band algorithm produced R2 of 0.75 and RMSE=1.79, and the three-band version generated R2 of 0.81 and RMSE=2.25ug

  19. Preliminary ECLSS waste water model

    Science.gov (United States)

    Carter, Donald L.; Holder, Donald W., Jr.; Alexander, Kevin; Shaw, R. G.; Hayase, John K.

    1991-01-01

    A preliminary waste water model for input to the Space Station Freedom (SSF) Environmental Control and Life Support System (ECLSS) Water Processor (WP) has been generated for design purposes. Data have been compiled from various ECLSS tests and flight sample analyses. A discussion of the characterization of the waste streams comprising the model is presented, along with a discussion of the waste water model and the rationale for the inclusion of contaminants in their respective concentrations. The major objective is to establish a methodology for the development of a waste water model and to present the current state of that model.

  20. Preliminary ECLSS waste water model

    Science.gov (United States)

    Carter, Donald L.; Holder, Donald W., Jr.; Alexander, Kevin; Shaw, R. G.; Hayase, John K.

    1991-01-01

    A preliminary waste water model for input to the Space Station Freedom (SSF) Environmental Control and Life Support System (ECLSS) Water Processor (WP) has been generated for design purposes. Data have been compiled from various ECLSS tests and flight sample analyses. A discussion of the characterization of the waste streams comprising the model is presented, along with a discussion of the waste water model and the rationale for the inclusion of contaminants in their respective concentrations. The major objective is to establish a methodology for the development of a waste water model and to present the current state of that model.

  1. Determination of inorganic contaminants in water

    Energy Technology Data Exchange (ETDEWEB)

    Cidu, R. [Cagliari Univ. (Italy). Dipt. di Scienze della Terra

    1998-12-31

    The determination of trace elements in water requires to follow adequate sampling and stabilization procedures. Filtration is carried out in situ using a metal-free system under oxygen-free conditions. Addition of acid for a ph value<1 prevents metal precipitation and/or adsorption onto the container walls. Field blank solutions prepared with the same procedure as with samples are necessary to monitor potential contamination. Ultrapure reagents are required to minimize contamination and to achieve the lowest detection limit. Significant improvements in detection limits can be obtained using a preconcentration method (e.g. evaporation, ion exchange, metal extraction into organic solvent). Analytical errors can be estimated using different techniques and analysing certified reference solutions. The determination of major components prior to trace element analysis allows samples to be sorted on increasing salinity contributing to reduce memory effects between samples, dilution can be used to reduce matrix effects, and the use of internal standards is efficient for instrumental drift correction.

  2. Modelling water temperature in TOXSWA

    NARCIS (Netherlands)

    Jacobs, C.M.J.; Deneer, J.W.; Adriaanse, P.I.

    2010-01-01

    A reasonably accurate estimate of the water temperature is necessary for a good description of the degradation of plant protection products in water which is used in the surface water model TOXSWA. Based on a consideration of basic physical processes that describe the influence of weather on the

  3. Application of bilinear factor models to determine water quality parameters in the optically complex waters of the Western Basin of Lake Erie using first-derivative VIS/NiR hyperspectral data

    Science.gov (United States)

    Adem Ali, K.; Ortiz, J. D.

    2012-12-01

    Lake Erie is biological the most active among the Great Lakes and experiences frequent large scale algal bloom during the summer period. Harmful algal blooms (HABs) such as Microcystis aeruginosa have been documented and these are of great concern for human health and are detrimental to the lake's biodiversity. Therefore, efficient lake monitoring tools are required for early detection and forecasting purposes. Satellite remote sensing is an efficient tool with high spatial and temporal coverage that can allow accurate and timely detection of HABs. However, in optically complex aquatic environments such as the Western Basin of Lake Erie (WBLE) where multiple color producing agents (CPAs) including phytoplankton, suspended sediment, and dissolved organic carbon are present the recorded spectra represent a convolution of the spectral responses from multiple constituents and the discrimination between the various constituents requires separation of the mostly overlapping scattering and absorption properties. This presents a challenge to the application of remote sensing data for determining a single in-water constituent. To assess the controls on the optical properties in the lake, we conducted weekly research cruises, collecting samples and conducting in-situ spectroscopy from a total of 90 stations that encompass many of the environments in Lake Erie ranging from deeper waters, shallower bay waters and riverine discharges. First-derivative of the hyperspectral data clearly revealed known spectral features of phytoplankton, a primary constituent in the WBLE, which include absorption minima near 560 and 700 nm attributed to the minimum absorption capacity and fluorescence effects, respectively. The signal also extracted the red absorption peak due to chlorophyll a (a proxy used for phytoplankton density) near 675 nm. Attenuation effects due to dissolved organic matter, detritus and suspended inorganic matters are also evident in the spectral signatures. This study

  4. Flood Water Crossing: Laboratory Model Investigations for Water Velocity Reductions

    Directory of Open Access Journals (Sweden)

    Kasnon N.

    2014-01-01

    Full Text Available The occurrence of floods may give a negative impact towards road traffic in terms of difficulties in mobilizing traffic as well as causing damage to the vehicles, which later cause them to be stuck in the traffic and trigger traffic problems. The high velocity of water flows occur when there is no existence of objects capable of diffusing the water velocity on the road surface. The shape, orientation and size of the object to be placed beside the road as a diffuser are important for the effective flow attenuation of water. In order to investigate the water flow, a laboratory experiment was set up and models were constructed to study the flow velocity reduction. The velocity of water before and after passing through the diffuser objects was investigated. This paper focuses on laboratory experiments to determine the flow velocity of the water using sensors before and after passing through two best diffuser objects chosen from a previous flow pattern experiment.

  5. Empirical model for chlorophyll-a determination in inland waters from the forthcoming Sentinel-2 and 3. Validation from HICO images

    Directory of Open Access Journals (Sweden)

    J. Delegido

    2014-06-01

    Full Text Available Chlorophyll-a concentration is one of the main indicators of inland waters quality. Using CHRIS/PROBA images and in situ data obtained in four lakes in Colombia and Spain, we obtained empirical models for the estimation of chlorophyll-a concentration, which can be directly applied to future images of MSI Sentinel-2 and OLCI Sentinel-3 sensors. The models, based on spectral band indices, were validated with data from the hyperspectral sensor HICO, onboard of the International Space Station.

  6. Community and household determinants of water quality in coastal Ghana.

    Science.gov (United States)

    McGarvey, Stephen T; Buszin, Justin; Reed, Holly; Smith, David C; Rahman, Zarah; Andrzejewski, Catherine; Awusabo-Asare, Kofi; White, Michael J

    2008-09-01

    Associations between water sources, socio-demographic characteristics and household drinking water quality are described in a representative sample of six coastal districts of Ghana's Central Region. Thirty-six enumeration areas (EAs) were randomly chosen from a representative survey of 90 EAs in rural, semi-urban and urban residence strata. In each EA, 24 households were randomly chosen for water quality sampling and socio-demographic interview. Escherichia coli per 100 ml H2O was quantified using the IDEXX Colilert system and multi-stage regression models estimated cross-sectional associations between water sources, sanitation and socio-demographic factors. Almost three quarters, 74%, of the households have > 2 E. coli /100 ml H2O. Tap water has significantly lower E. coli levels compared with surface or rainwater and well water had the highest levels. Households with a water closet toilet have significantly lower E. coli compared with those using pit latrines or no toilets. Household size is positively associated, and a possessions index is negatively associated, with E. coli. Variations in community and household socio-demographic and behavioural factors are key determinants of drinking water quality. These factors should be included in planning health education associated with investments in water systems.

  7. Root water uptake as simulated by three water flow models

    NARCIS (Netherlands)

    Willigen, de P.; Dam, van J.C.; Javaux, M.; Heinen, M.

    2012-01-01

    The objective of our study was to determine to what extent four root water uptake (RWU) models differed when tested under extreme conditions. Cumulative transpiration patterns were similar, contrary to the spatial extraction patterns. The analysis showed that both soil physical and root physiologica

  8. Water Stress Projection Modeling

    Science.gov (United States)

    2016-09-01

    facility. Stationing analysis done with climate forecasting in mind recognizes an unpredictable future, while striving to best prepare for the...to support additional growth. This attribute places a threshold ca- pacity on water supply and treatment, which may be related to treat- ment plant ...et al. 2013). 3.3 Military impacts reduced water Extreme weather events such as droughts, floods, snow, and ice storms have significant impacts on

  9. Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

    Directory of Open Access Journals (Sweden)

    B. D. Castro

    2005-09-01

    Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.

  10. Headspace chromatographic determination of water pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Otson, R.; Williams, D.T.

    1982-05-01

    A readily constructed, automated purging assembly, on-column trapping, and simultaneous use of flame ionization and electrolytic conductivity detectors were applied to develop a dynamic headspace gas chromatographic technique which was evaluated for the determination of 42 organic polluants in water. Detection limits of <1 ..mu..g/L and linear plots of peak area against concentration in the range 0.25-16 ..mu..g/L were obtained for 32 compounds. At aqueous concentrations of 4 and 16 ..mu..g/L, peak area precision of <10% relative standard deviation (RSD) for triplicate sample analysis and purging efficiencies of >75% were generally obtained. Storage of aqueous composite standard solutions at 4 and 16 ..mu..g/L for 6 weeks at 4/sup 0/C did not usually affect analytical results by more than +/- 15%.

  11. Classical interaction model for the water molecule.

    Science.gov (United States)

    Baranyai, András; Bartók, Albert

    2007-05-14

    The authors propose a new classical model for the water molecule. The geometry of the molecule is built on the rigid TIP5P model and has the experimental gas phase dipole moment of water created by four equal point charges. The model preserves its rigidity but the size of the charges increases or decreases following the electric field created by the rest of the molecules. The polarization is expressed by an electric field dependent nonlinear polarization function. The increasing dipole of the molecule slightly increases the size of the water molecule expressed by the oxygen-centered sigma parameter of the Lennard-Jones interaction. After refining the adjustable parameters, the authors performed Monte Carlo simulations to check the ability of the new model in the ice, liquid, and gas phases. They determined the density and internal energy of several ice polymorphs, liquid water, and gaseous water and calculated the heat capacity, the isothermal compressibility, the isobar heat expansion coefficients, and the dielectric constant of ambient water. They also determined the pair-correlation functions of ambient water and calculated the energy of the water dimer. The accuracy of theirs results was satisfactory.

  12. Modeling Water Quality in Rivers

    Directory of Open Access Journals (Sweden)

    Liren Yu

    2005-01-01

    Full Text Available This study reports a PC software, used in a Windows-based environment, which was developed based on the first order reaction of Biological Oxygen Demand (BOD and a modified Streeter and Phelps equation, in order to simulate and determine the variations of Dissolved Oxygen (DO and of the BOD along with the studied river reaches. The software considers many impacts of environmental factors, such as the different type of discharges (concentrated or punctual source, tributary contribution, distributed source, nitrogenous BOD, BOD sedimentation, photosynthetic production and benthic demand of oxygen, and so on. The software has been used to model the DO profile along one river, with the aim to improve the water quality through suitable engineering measure.

  13. An Improved Frequency Domain Technique for Determining Soil Water Content

    Institute of Scientific and Technical Information of China (English)

    SUN Yu-Rui; MA Dao-Kun; LIN Jian-Hui; P. SCHULZE LAMMERS; L. DAMEROW

    2005-01-01

    For many years a soil water content sensor with low cost, reliability and sufficient accuracy has been desirable. Thus,an improved measurement method based on the frequency domain (FD) principle for determining soil water content was considered. Unlike other measurement principles, a new measurable index, η, which was independent of the output impedance and the amplitude of the oscillator while relying on the electrical impedance of a multi-pin probe, was proposed. Moreover, a model for processing the impedance of the multi-pin soil probe was developed, and several important electrical parameters for establishing their operating ranges applicable to this probe were evaluated. In order to confirm the theoretical analysis, an experiment was conducted with a 4-pin probe. Using the developed model, the relationship between the proposed indexηand soil volumetric water content was shown to be linear (R2 = 0.9921). Thus, as the measurable index, ηseemed satisfactory.

  14. Experimental determination of water activity for binary aqueous cerium(III) ionic solutions: application to an assessment of the predictive capability of the binding mean spherical approximation model.

    Science.gov (United States)

    Ruas, Alexandre; Simonin, Jean-Pierre; Turq, Pierre; Moisy, Philippe

    2005-12-08

    This work is aimed at a description of the thermodynamic properties of actinide salt solutions at high concentration. The predictive capability of the binding mean spherical approximation (BIMSA) theory to describe the thermodynamic properties of electrolytes is assessed in the case of aqueous solutions of lanthanide(III) nitrate and chloride salts. Osmotic coefficients of cerium(III) nitrate and chloride were calculated from other lanthanide(III) salts properties. In parallel, concentrated binary solutions of cerium nitrate were prepared in order to measure experimentally its water activity and density as a function of concentration, at 25 degrees C. Water activities of several binary solutions of cerium chloride were also measured to check existing data on this salt. Then, the properties of cerium chloride and cerium nitrate solutions were compared within the BIMSA model. Osmotic coefficient values for promethium nitrate and promethium chloride given by this theory are proposed. Finally, water activity measurements were made to examine the fact that the ternary system Ce(NO3)3/HNO3/H2O and the quaternary system Ce(NO3)3/HNO3/N2H5NO3/H2O may be regarded as "simple solutions" (in the sense of Zdanovskii and Mikulin).

  15. Modeling Water Filtration

    Science.gov (United States)

    Parks, Melissa

    2014-01-01

    Model-eliciting activities (MEAs) are not new to those in engineering or mathematics, but they were new to Melissa Parks. Model-eliciting activities are simulated real-world problems that integrate engineering, mathematical, and scientific thinking as students find solutions for specific scenarios. During this process, students generate solutions…

  16. Modeled ground water age distributions

    Science.gov (United States)

    Woolfenden, Linda R.; Ginn, Timothy R.

    2009-01-01

    The age of ground water in any given sample is a distributed quantity representing distributed provenance (in space and time) of the water. Conventional analysis of tracers such as unstable isotopes or anthropogenic chemical species gives discrete or binary measures of the presence of water of a given age. Modeled ground water age distributions provide a continuous measure of contributions from different recharge sources to aquifers. A numerical solution of the ground water age equation of Ginn (1999) was tested both on a hypothetical simplified one-dimensional flow system and under real world conditions. Results from these simulations yield the first continuous distributions of ground water age using this model. Complete age distributions as a function of one and two space dimensions were obtained from both numerical experiments. Simulations in the test problem produced mean ages that were consistent with the expected value at the end of the model domain for all dispersivity values tested, although the mean ages for the two highest dispersivity values deviated slightly from the expected value. Mean ages in the dispersionless case also were consistent with the expected mean ages throughout the physical model domain. Simulations under real world conditions for three dispersivity values resulted in decreasing mean age with increasing dispersivity. This likely is a consequence of an edge effect. However, simulations for all three dispersivity values tested were mass balanced and stable demonstrating that the solution of the ground water age equation can provide estimates of water mass density distributions over age under real world conditions.

  17. Storm Water Management Model (SWMM)

    Science.gov (United States)

    EPA's Storm Water Management Model (SWMM) is used throughout the world for planning, analysis and design related to stormwater runoff, combined and sanitary sewers, and other drainage systems in urban areas.

  18. Modelling Ballast Water Transport

    Digital Repository Service at National Institute of Oceanography (India)

    Jayakumar, S.; Babu, M.T.; Vethamony, P.

    by toolbox, available in MIKE software, by predicting the water elevation using the four major constituents M2, S2, K1 and O1 at the coastal tidal stations Okha and Godia (International Hydrographic Bureau, Spec. Pub, Monaco). Subsequently the tidal...-gulf is the highest compared to that on the northern and southern coasts. References Panvelkar, J.S., Bendre, V.M. and A.S.Barve (1986). ?Software for harmonic and spectral analysis of tidal data?, Proc. 3rd Indian Conference on ocean engineering, IIT Bombay, Dec...

  19. Integrated Water Resources Simulation Model for Rural Community

    Science.gov (United States)

    Li, Y.-H.; Liao, W.-T.; Tung, C.-P.

    2012-04-01

    The purpose of this study is to develop several water resources simulation models for residence houses, constructed wetlands and farms and then integrate these models for a rural community. Domestic and irrigation water uses are the major water demand in rural community. To build up a model estimating domestic water demand for residence houses, the average water use per person per day should be accounted first, including water uses of kitchen, bathroom, toilet and laundry. On the other hand, rice is the major crop in the study region, and its productive efficiency sometimes depends on the quantity of irrigation water. The water demand can be estimated by crop water use, field leakage and water distribution loss. Irrigation water comes from rainfall, water supply system and reclaimed water which treated by constructed wetland. In recent years, constructed wetlands play an important role in water resources recycle. They can purify domestic wastewater for water recycling and reuse. After treating from constructed wetlands, the reclaimed water can be reused in washing toilets, watering gardens and irrigating farms. Constructed wetland is one of highly economic benefits for treating wastewater through imitating the processing mechanism of natural wetlands. In general, the treatment efficiency of constructed wetlands is determined by evapotranspiration, inflow, and water temperature. This study uses system dynamics modeling to develop models for different water resource components in a rural community. Furthermore, these models are integrated into a whole system. The model not only is utilized to simulate how water moves through different components, including residence houses, constructed wetlands and farms, but also evaluates the efficiency of water use. By analyzing the flow of water, the water resource simulation model can optimizes water resource distribution under different scenarios, and the result can provide suggestions for designing water resource system of a

  20. River water quality modelling: II

    DEFF Research Database (Denmark)

    Shanahan, P.; Henze, Mogens; Koncsos, L.

    1998-01-01

    The U.S. EPA QUAL2E model is currently the standard for river water quality modelling. While QUAL2E is adequate for the regulatory situation for which it was developed (the U.S. wasteload allocation process), there is a need for a more comprehensive framework for research and teaching. Moreover......, and to achieve robust model calibration. Mass balance problems arise from failure to account for mass in the sediment as well as in the water column and due to the fundamental imprecision of BOD as a state variable. (C) 1998 IAWQ Published by Elsevier Science Ltd. All rights reserved....

  1. Experimental determination and chemical modelling of radiolytic processes at the spent fuel/water interface. Experiments carried out in carbonate solutions in absence and presence of chloride

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Jordi; Cera, Esther; Grive, Mireia; Duro, Lara [Enviros Spain SL (Spain); Eriksen, Trygve [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Nuclear Chemistry

    2003-01-01

    We report on the recent experimental and modelling results of a research programme that started in 1995. The aim has been to understand the kinetic and thermodynamic processes that control the radiolytic generation of oxidants and reductants at the spent fuel water interface and their consequences for spent fuel matrix stability and radionuclide release. This has been done by carrying out well-controlled dissolution experiments of PWR Ringhals spent fuel fragments in an initially anoxic closed system and by using different solution compositions. Experimental series started with several tests carried out with deionised water as solvent, in a second phase experiments were conducted with 10 mM bicarbonate solutions. New experimental series were set up during the last two years by using the same bicarbonate content in solutions with varying NaCl concentrations in order to ascertain the role of this ligand on the radiolytic products and its consequence for radionuclide release. The selected NaCl concentrations are in the range of 0.1 to 10 mM. Experimental data shows that uranium dissolution at early contact times is controlled by the oxidation of the UO{sub 2} matrix. This process controls the co-dissolution of most of the analysed radionuclides, including Sr, Mo, Tc, Np and surprisingly enough, Cs. In the overall the release rates for U and the matrix associated radionuclides are in the range of 10{sup -6} moles/day with a clear decreasing trend with exposure time and after 2 years the initial release rates have decreased down to 3x10{sup -8} moles/day. The solubility of the released actinides appears to be limited by the formation of An(IV) hydroxide phases, although Np concentrations in solution did not reach solubility levels during the time intervals of the present tests. No secondary solid phase appears to control the solubility of the rest of the elements.

  2. Modeling water waves beyond perturbations

    CERN Document Server

    Clamond, Didier

    2015-01-01

    In this chapter, we illustrate the advantage of variational principles for modeling water waves from an elementary practical viewpoint. The method is based on a `relaxed' variational principle, i.e., on a Lagrangian involving as many variables as possible, and imposing some suitable subordinate constraints. This approach allows the construction of approximations without necessarily relying on a small parameter. This is illustrated via simple examples, namely the Serre equations in shallow water, a generalization of the Klein-Gordon equation in deep water and how to unify these equations in arbitrary depth. The chapter ends with a discussion and caution on how this approach should be used in practice.

  3. The EPANET water quality model

    Energy Technology Data Exchange (ETDEWEB)

    Rossman, L.A. [Environmental Protection Agency, Cincinnati, OH (United States)

    1995-10-01

    EPANET is a software package developed by US EPA`s Drinking Water Research Division for modeling hydraulic and water quality behavior within water distribution systems. Starting with a geometric description of the pipe network, a set of initial conditions, estimates of water usage, and a set of rules for how the system is operated, EPANET predicts all flows, pressures, and water quality levels throughout the network during an extended period of operation. In addition to substance concentration, water age and source tracing can also be simulated. EPANET offers a number of advanced features including: modular, highly portable C language code with no pre-set limits on network size; a simple data input format based on a problem oriented language; a full-featured hydraulic simulator; improved water quality algorithms; analysis of water quality reactions both within the bulk flow and at the pipe wall; an optional graphical user interface running under Microsoft{reg_sign} Windows{trademark}. The Windows user interface allows one to edit EPANET input files, run a simulation, and view the results all within a single program. Simulation output can be visualized through: color-coded maps of the distribution system with full zooming, panning and labeling capabilities and a slider control to move forward or backward through time; spreadsheet-like tables that can be searched for entries meeting a specified criterion; and time series graphs of both predicted and observed values for any variable at any location in the network. EPANET is currently being used to analyze a number of water quality issues in different distribution systems across the country. These include: chlorine decay dynamics, raw water source blending, altered tank operation, and integration with real-time monitoring and control systems.

  4. Water Distribution and Removal Model

    Energy Technology Data Exchange (ETDEWEB)

    Y. Deng; N. Chipman; E.L. Hardin

    2005-08-26

    The design of the Yucca Mountain high level radioactive waste repository depends on the performance of the engineered barrier system (EBS). To support the total system performance assessment (TSPA), the Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is developed to describe the thermal, mechanical, chemical, hydrological, biological, and radionuclide transport processes within the emplacement drifts, which includes the following major analysis/model reports (AMRs): (1) EBS Water Distribution and Removal (WD&R) Model; (2) EBS Physical and Chemical Environment (P&CE) Model; (3) EBS Radionuclide Transport (EBS RNT) Model; and (4) EBS Multiscale Thermohydrologic (TH) Model. Technical information, including data, analyses, models, software, and supporting documents will be provided to defend the applicability of these models for their intended purpose of evaluating the postclosure performance of the Yucca Mountain repository system. The WD&R model ARM is important to the site recommendation. Water distribution and removal represents one component of the overall EBS. Under some conditions, liquid water will seep into emplacement drifts through fractures in the host rock and move generally downward, potentially contacting waste packages. After waste packages are breached by corrosion, some of this seepage water will contact the waste, dissolve or suspend radionuclides, and ultimately carry radionuclides through the EBS to the near-field host rock. Lateral diversion of liquid water within the drift will occur at the inner drift surface, and more significantly from the operation of engineered structures such as drip shields and the outer surface of waste packages. If most of the seepage flux can be diverted laterally and removed from the drifts before contacting the wastes, the release of radionuclides from the EBS can be controlled, resulting in a proportional reduction in dose release at the accessible environment. The purposes

  5. Methods for Determining Organic Matter and Colour in Water

    Directory of Open Access Journals (Sweden)

    Ramunė Albrektienė

    2011-02-01

    Full Text Available The article examines different methods for determining organic matter and colour in water. Most of organic compounds in water have a humic substance. These substances frequently form complexes with iron. Humic matter gives water a yellow-brownish colour. Water filtration through conventional sand filters does not remove colour and organic compounds, and therefore complicated water treatment methods shall be applied. The methods utilized for organic matter determination in water included research on total organic carbon, permanganate index and the bichromate number of UV absorption of 254 nm wave length. The obtained results showed the greatest dependence between water colour and permanganate index. However, UV adsorption could be used for organic matter determination during the operation of a water treatment plant and the start-up of plants as easy and fast methods.Article in Lithuanian

  6. Optimisation of ATP determination in drinking water

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    Adenosine Triphosphate (ATP) can be used as a relative measure of cell activity, and is measured by the light output from the reaction between luciferin and ATP catalyzed by firefly luciferase. The measurement has potential as a monitoring and surveillance tool within drinking water distribution......, since the method is very sensitive (detects 0.5 ng ATP/L) and results are obtained within minutes. When calculating the ATP value a number of parameters need to be considered. These were investigate by use of two different reagent kits (PCP-kit and Lumin(ATE)/Lumin(EX)-kit), internal standard...... and an Advance Coupe luminometer. The investigations showed a 60 times higher response of the PCP-kit, making it more suitable for measurement of samples with low ATP content. ATP-standard dilutions prepared in tap water were stable for at least 15 months when stored frozen at -80ºC, and storage of large...

  7. Optimisation of ATP determination in drinking water

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    Adenosine Triphosphate (ATP) can be used as a relative measure of cell activity, and is measured by the light output from the reaction between luciferin and ATP catalyzed by firefly luciferase. The measurement has potential as a monitoring and surveillance tool within drinking water distribution......, since the method is very sensitive (detects 0.5 ng ATP/L) and results are obtained within minutes. When calculating the ATP value a number of parameters need to be considered. These were investigate by use of two different reagent kits (PCP-kit and Lumin(ATE)/Lumin(EX)-kit), internal standard...... and an Advance Coupe luminometer. The investigations showed a 60 times higher response of the PCP-kit, making it more suitable for measurement of samples with low ATP content. ATP-standard dilutions prepared in tap water were stable for at least 15 months when stored frozen at -80ºC, and storage of large...

  8. World water dynamics: global modeling of water resources.

    Science.gov (United States)

    Simonovic, Slobodan P

    2002-11-01

    The growing scarcity of fresh and clean water is among the most important issues facing civilization in the 21st century. Despite the growing attention to a chronic, pernicious crisis in world's water resources our ability to correctly assess and predict global water availability, use and balance is still quite limited. An attempt is documented here in modeling global world water resources using system dynamics approach. Water resources sector (quantity and quality) is integrated with five sectors that drive industrial growth: population; agriculture; economy; nonrenewable resources; and persistent pollution. WorldWater model is developed on the basis of the last version of World3 model. Simulations of world water dynamics with WorldWater indicate that there is a strong relationship between the world water resources and future industrial growth of the world. It is also shown that the water pollution is the most important future water issue on the global level.

  9. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

    Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment

  10. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

    Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment concentrati

  11. Determination of oil/water and octanol/water distribution coefficients from aqueous solutions from four fossil fuels. [MS thesis; in oil-water and octanol-water

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, B.L.

    1984-07-01

    Liquid fossil fuels, both petroleum and synthetically derived oils, are exceedingly complex mixtures of thousands of components. The effect of many of these energy-related components on the environment is largely unknown. Octanol/water distribution coefficients relate both to toxicity and to the bioaccumulation potential of chemical components. Use of these partition data in conjunction with component concentrations in the oils in environmental models provides important information on the fate of fossil fuel components when released to the environment. Octanol/water distribution data are not available for many energy-related organic compounds, and those data that are available have been determined for individual components in simple, one-component octanol/water equilibrium mixtures. In this study, methods for determining many octanol/water distribution coefficients from aqueous extracts of oil products were developed. Sample aqueous mixtures were made by equilibrating liquid fossil fuels with distilled water. This approach has the advantage of detecting interactions between components of interest and other sample components. Compound types studied included phenols, nitrogen bases, hydrocarbons, sulfur heterocyclic compounds, and carboxylic acids. Octanol/water distribution coefficients that were determined in this study ranged from 9.12 for aniline to 67,600 for 1,2-dimethylnaphthalene. Within a compound type, distribution coefficients increased logarithmically with increasing alkyl substitution and molecular weight. Additionally, oil/water distribution data were determined for oil components. These data are useful in predicting maximum environmental concentrations in water columns. 96 references, 26 figures, and 40 tables.

  12. Stochastic Still Water Response Model

    DEFF Research Database (Denmark)

    Friis-Hansen, Peter; Ditlevsen, Ove Dalager

    2002-01-01

    In this study a stochastic field model for the still water loading is formulated where the statistics (mean value, standard deviation, and correlation) of the sectional forces are obtained by integration of the load field over the relevant part of the ship structure. The objective of the model...... is to establish the stochastic load field conditional on a given draft and trim of the vessel. The model contributes to a realistic modelling of the stochastic load processes to be used in a reliability evaluation of the ship hull. Emphasis is given to container vessels. The formulation of the model for obtaining...... the stochastic cargo container load field is based on a queuing and loading policy that assumes containers are handled by a first-come-first-serve policy. The load field is assumed to be Gaussian. The ballast system is imposed to counteract the angle of heel and to regulate both the draft and the trim caused...

  13. Determining the quality of water in environmental measuring technology

    Energy Technology Data Exchange (ETDEWEB)

    Bonfig, K.W.; Kramp, E.

    1983-11-01

    The present high degree of pollution of our water resources due to environmental effects endangers the natural cleaning processes. With the growing demand for water from domestic, industrial and other users, certain minimum requirements must be postulated for the quality of water returned to the natural circuit. This requires continuous control and monitoring of the quality of water in many industrial and community areas, such as water treatment plants, for example. Measuring processes and equipment are used to an increasing degree here. This article reports on processes for determining important parameters for the quality of water. Processes with and without treatment of samples are mentioned.

  14. Modeling Water Pollution of Soil

    Directory of Open Access Journals (Sweden)

    V. Doležel

    2008-01-01

    depth of 220–300 m below the terrain. As an alternative, thinner stoppers were considered, but this option was discarded.The aim of this paper is to describe the design of the stoppers applied to separate the two types of water along the contact horizon using Desai’s DSC theory (Distinct State Concept, and generalized plane strain in the multiphase problem of water flow in a porous medium. In addition, a comparison of some results from scale experimental models with numerical solutions was carried out. The intrinsic material properties of stoppers for numerical computations were obtained from physical and chemical laboratory tests. The models were evaluated for the complete underground work, particularly in its final stage of construction. 

  15. Accounting for Water Insecurity in Modeling Domestic Water Demand

    Science.gov (United States)

    Galaitsis, S. E.; Huber-lee, A. T.; Vogel, R. M.; Naumova, E.

    2013-12-01

    Water demand management uses price elasticity estimates to predict consumer demand in relation to water pricing changes, but studies have shown that many additional factors effect water consumption. Development scholars document the need for water security, however, much of the water security literature focuses on broad policies which can influence water demand. Previous domestic water demand studies have not considered how water security can affect a population's consumption behavior. This study is the first to model the influence of water insecurity on water demand. A subjective indicator scale measuring water insecurity among consumers in the Palestinian West Bank is developed and included as a variable to explore how perceptions of control, or lack thereof, impact consumption behavior and resulting estimates of price elasticity. A multivariate regression model demonstrates the significance of a water insecurity variable for data sets encompassing disparate water access. When accounting for insecurity, the R-squaed value improves and the marginal price a household is willing to pay becomes a significant predictor for the household quantity consumption. The model denotes that, with all other variables held equal, a household will buy more water when the users are more water insecure. Though the reasons behind this trend require further study, the findings suggest broad policy implications by demonstrating that water distribution practices in scarcity conditions can promote consumer welfare and efficient water use.

  16. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  17. Hydrodynamic modeling of Singapore's coastal waters: Nesting and model accuracy

    Science.gov (United States)

    Hasan, G. M. Jahid; van Maren, Dirk Sebastiaan; Ooi, Seng Keat

    2016-01-01

    The tidal variation in Singapore's coastal waters is influenced by large-scale, complex tidal dynamics (by interaction of the Indian Ocean and the South China Sea) as well as monsoon-driven low frequency variations, requiring a model with large spatial coverage. Close to the shores, the complex topography, influenced by headlands and small islands, requires a high resolution model to simulate tidal dynamics. This can be achieved through direct nesting or multi-scale nesting, involving multiple model grids. In this paper, we investigate the effect of grid resolution and multi-scale nesting on the tidal dynamics in Singapore's coastal waters, by comparing model results with observations using different statistical techniques. The results reveal that the intermediate-scale model is generally sufficiently accurate (equal to or better than the most refined model), but also that the most refined model is only more accurate when nested in the intermediate scale model (requiring multi-scale nesting). This latter is the result of the complex tidal dynamics around Singapore, where the dominantly diurnal tidal currents are decoupled from the semi-diurnal water level variations. Furthermore, different techniques to quantify model accuracy (harmonic analysis, basic statistics and more complex statistics) are inconsistent in determining which model is more accurate.

  18. Semiempirical model of soil water hysteresis

    Science.gov (United States)

    Nimmo, J.R.

    1992-01-01

    In order to represent hysteretic soil water retention curves accurately using as few measurements as possible, a new semiempirical model has been developed. It has two postulates related to physical characteristics of the medium, and two parameters, each with a definite physical interpretation, whose values are determined empirically for a given porous medium. Tests of the model show that it provides high-quality optimized fits to measured water content vs. matric pressure wetting curves for a wide variety of media. A practical use of this model is to provide a complete simulated main wetting curve for a medium where only a main drying curve and two points on the wetting curve have been measured. -from Author

  19. Determinantes psicológicos e situacionais do comportamento de conservação de água: um modelo estrutural Psychological and situational determinants of water conservation behavior: a structural model

    Directory of Open Access Journals (Sweden)

    Víctor Corral-Verdugo

    2003-08-01

    of water, and their conservation motives were assessed using a questionnaire. The possession of furniture for using water was considered as one situational factor promoting water consumption, and water scarcity was considered as a potential inhibitor of that consumption. These variables were incorporated in a structural model. Results of this model revealed that water consumption was significantly and positively influenced by utilitarian beliefs and the possession of furniture, while conservation motives, conservation skills and water scarcity inhibited such consumption. Conservation motives were positively affected by water scarcity and conservation skills, and negatively influenced by utilitarian beliefs. Significant covariances between the determinants of water consumption revealed the interdependence of situational and psychological variables affecting water use.

  20. Hydrocarbons on sea water: steady-state spreading signatures determined

    Directory of Open Access Journals (Sweden)

    Adriana Mazurek

    2007-09-01

    Full Text Available The spreading properties of several hydrocarbons (vegetable,engine, gear and crude oils on distilled and artificial seawater were determined under laboratory conditions using a noveloptical method. With the aid of Langmuir's equation, the geometricalsignatures of a discrete lens of each hydrocarbon droplet floatingon a water tank served to calculate the enteringE (31.30-94.18 mN m-1 and spreadingS (-3.50 to -57.49 mN m-1 coefficients, and equilibriumthicknesses t∞ (0.20-1.25 cm. They appeared to be in agreementwith the values derived from direct interfacial tension measurements (Wilhelmyplate and stalagmometer methods. Empirical relations of the normalized lensradius rL / rdrop and S on the water surface tensionγAW were postulated as being of significant value in oil spillassessment studies at sea. The parameters obtained together with the surfaceproperties of a natural surfactant-containing water body represent theprincipal input data required for modelling the spreading of asurface-tension-gradient-driven oil spill at sea.

  1. Hydraulic modelling of drinking water treatment plant operations

    OpenAIRE

    L. C. Rietveld; Borger, K.J.; Van Schagen, K.M.; Mesman, G.A.M.; G. I. M. Worm

    2008-01-01

    For a drinking water treatment plant simulation, water quality models, a hydraulic model, a process-control model, an object model, data management, training and decision-support features and a graphic user interface have been integrated. The integration of a hydraulic model in the simulator is necessary to correctly determine the division of flows over the plant's lanes and, thus, the flow through the individual treatment units, based on valve positions and pump speeds. The flow through a un...

  2. On the determination of the mean excitation energy of water

    DEFF Research Database (Denmark)

    Sabin, John R.; Oddershede, Jens; Sauer, Stephan P. A.

    2013-01-01

    Water is a ubiquitous substance in nature, and thus the mean excitation energy of water is an important quantity for understanding and prediction of the details of many fast ion/molecule collision processes such as those involved in external beam radiotherapy of tumors. There are several methods...... for determining numerical values for a mean excitation energy for water, both theoretical and experimental. Here the factors affecting the determination of the value of the mean excitation energy of water, especially from experiment, are discussed....

  3. Water losses dynamic modelling in water distribution networks

    Science.gov (United States)

    Puleo, Valeria; Milici, Barbara

    2015-12-01

    In the last decades, one of the main concerns of the water system managers have been the minimisation of water losses, that frequently reach values of 30% or even 70% of the volume supplying the water distribution network. The economic and social costs associated with water losses in modern water supply systems are rapidly rising to unacceptably high levels. Furthermore, the problem of the water losses assumes more and more importance mainly when periods of water scarcity occur or when not sufficient water supply takes part in areas with fast growth. In the present analysis, a dynamic model was used for estimating real and apparent losses of a real case study. A specific nodal demand model reflecting the user's tank installation and a specific apparent losses module were implemented. The results from the dynamic model were compared with the modelling estimation based on a steady-state approach.

  4. Phase Equilibria of Water/CO2 and Water/n-Alkane Mixtures from Polarizable Models.

    Science.gov (United States)

    Jiang, Hao; Economou, Ioannis G; Panagiotopoulos, Athanassios Z

    2017-02-16

    Phase equilibria of water/CO2 and water/n-alkane mixtures over a range of temperatures and pressures were obtained from Monte Carlo simulations in the Gibbs ensemble. Three sets of Drude-type polarizable models for water, namely the BK3, GCP, and HBP models, were combined with a polarizable Gaussian charge CO2 (PGC) model to represent the water/CO2 mixture. The HBP water model describes hydrogen bonds between water and CO2 explicitly. All models underestimate CO2 solubility in water if standard combining rules are used for the dispersion interactions between water and CO2. With the dispersion parameters optimized to phase compositions, the BK3 and GCP models were able to represent the CO2 solubility in water, however, the water composition in CO2-rich phase is systematically underestimated. Accurate representation of compositions for both water- and CO2-rich phases cannot be achieved even after optimizing the cross interaction parameters. By contrast, accurate compositions for both water- and CO2-rich phases were obtained with hydrogen bonding parameters determined from the second virial coefficient for water/CO2. Phase equilibria of water/n-alkane mixtures were also studied using the HBP water and an exponenial-6 united-atom n-alkanes model. The dispersion interactions between water and n-alkanes were optimized to Henry's constants of methane and ethane in water. The HBP water and united-atom n-alkane models underestimate water content in the n-alkane-rich phase; this underestimation is likely due to the neglect of electrostatic and induction energies in the united-atom model.

  5. Clusters of classical water models

    Science.gov (United States)

    Kiss, Péter T.; Baranyai, András

    2009-11-01

    The properties of clusters can be used as tests of models constructed for molecular simulation of water. We searched for configurations with minimal energies for a small number of molecules. We identified topologically different structures close to the absolute energy minimum of the system by calculating overlap integrals and enumerating hydrogen bonds. Starting from the dimer, we found increasing number of topologically different, low-energy arrangements for the trimer(3), the tetramer(6), the pentamer(6), and the hexamer(9). We studied simple models with polarizable point dipole. These were the BSV model [J. Brodholt et al., Mol. Phys. 86, 149 (1995)], the DC model [L. X. Dang and T. M. Chang, J. Chem. Phys. 106, 8149 (1997)], and the GCP model [P. Paricaud et al., J. Chem. Phys. 122, 244511 (2005)]. As an alternative the SWM4-DP and the SWM4-NDP charge-on-spring models [G. Lamoureux et al., Chem. Phys. Lett. 418, 245 (2006)] were also investigated. To study the impact of polarizability restricted to the plane of the molecule we carried out calculations for the SPC-FQ and TIP4P-FQ models, too [S. W. Rick et al., J. Chem. Phys. 101, 6141 (1994)]. In addition to them, justified by their widespread use even for near critical or surface behavior calculations, we identified clusters for five nonpolarizable models of ambient water, SPC/E [H. J. C. Berendsen et al., J. Phys. Chem. 91, 6269 (1987)], TIP4P [W. L. Jorgensen et al., J. Chem. Phys. 79, 926 (1983)], TIP4P-EW [H. W. Horn et al., J. Chem. Phys. 120, 9665 (2004)], and TIP4P/2005 [J. L. F. Abascal and C. Vega, J. Chem. Phys. 123, 234505 (2005)]. The fifth was a five-site model named TIP5P [M. W. Mahoney and W. L. Jorgensen, J. Chem. Phys. 112, 8910 (2000)]. To see the impact of the vibrations we studied the flexible SPC model. [K. Toukan and A. Rahman, Phys. Rev. B 31, 2643 (1985)]. We evaluated the results comparing them with experimental data and quantum chemical calculations. The position of the negative

  6. Water quality: determination of dissolved oxygen : electrochemical probe method

    National Research Council Canada - National Science Library

    2012-01-01

    ISO 5814:2012 specifies an electrochemical method for the determination of dissolved oxygen in water by means of an electrochemical cell which is isolated from the sample by a gas permeable membrane...

  7. Global modelling of Cryptosporidium in surface water

    Science.gov (United States)

    Vermeulen, Lucie; Hofstra, Nynke

    2016-04-01

    Conclusions GloWPa-Crypto is the first global model that can be used to analyse dynamics in surface water pathogen concentrations worldwide. Global human Cryptosporidium emissions are estimated at 1 x 10^17 oocysts/ year for the year 2010.We estimated future emissions for SSP1 and SSP3. Preliminary results show that for SSP1human emissions are approximately halved by 2050. The SSP3 human emissions are 1.5 times higher than the 2010 emissions due to increased population growth and urbanisation. Livestock Cryptosporidium emissions are expected to increase under both SSP1 and SSP3, as meat consumption continues to rise. We conclude that population growth, urbanization, changes in sanitation systems and treatment, and changes in livestock consumption and production systems are important processes that determine future Cryptosporidium emissions to surface water. References Hofstra N, Bouwman A F, Beusen A H W and Medema G J 2013 Exploring global Cryptosporidium emissions to surface water Sci. Total Environ. 442 10-9 Kiulia N M, Hofstra N, Vermeulen L C, Obara M A, Medema G J and Rose J B 2015 Global occurrence and emission of rotaviruses to surface waters Pathogens 4 229-55 Vermeulen L C, De Kraker J, Hofstra N, Kroeze C and Medema G J 2015 Modelling the impact of sanitation, population and urbanization estimates on human emissions of Cryptosporidium to surface waters - a case study for Bangladesh and India Environ. Res. Lett. 10

  8. Artificial neural networks for defining the water quality determinants of groundwater abstraction in coastal aquifer

    Science.gov (United States)

    Lallahem, S.; Hani, A.

    2017-02-01

    Water sustainability in the lower Seybouse River basin, eastern Algeria, must take into account the importance of water quantity and quality integration. So, there is a need for a better knowledge and understanding of the water quality determinants of groundwater abstraction to meet the municipal and agricultural uses. In this paper, the artificial neural network (ANN) models were used to model and predict the relationship between groundwater abstraction and water quality determinants in the lower Seybouse River basin. The study area chosen is the lower Seybouse River basin and real data were collected from forty five wells for reference year 2006. Results indicate that the feed-forward multilayer perceptron models with back-propagation are useful tools to define and prioritize the important water quality parameters of groundwater abstraction and use. The model evaluation shows that the correlation coefficients are more than 95% for training, verification and testing data. The model aims to link the water quantity and quality with the objective to strengthen the Integrated Water Resources Management approach. It assists water planners and managers to better assess the water quality parameters and progress towards the provision of appropriate quantities of water of suitable quality.

  9. Modeling water demand when households have multiple sources of water

    Science.gov (United States)

    Coulibaly, Lassina; Jakus, Paul M.; Keith, John E.

    2014-07-01

    A significant portion of the world's population lives in areas where public water delivery systems are unreliable and/or deliver poor quality water. In response, people have developed important alternatives to publicly supplied water. To date, most water demand research has been based on single-equation models for a single source of water, with very few studies that have examined water demand from two sources of water (where all nonpublic system water sources have been aggregated into a single demand). This modeling approach leads to two outcomes. First, the demand models do not capture the full range of alternatives, so the true economic relationship among the alternatives is obscured. Second, and more seriously, economic theory predicts that demand for a good becomes more price-elastic as the number of close substitutes increases. If researchers artificially limit the number of alternatives studied to something less than the true number, the price elasticity estimate may be biased downward. This paper examines water demand in a region with near universal access to piped water, but where system reliability and quality is such that many alternative sources of water exist. In extending the demand analysis to four sources of water, we are able to (i) demonstrate why households choose the water sources they do, (ii) provide a richer description of the demand relationships among sources, and (iii) calculate own-price elasticity estimates that are more elastic than those generally found in the literature.

  10. Ionometric determination of chloride ion in circulating and waste waters

    Energy Technology Data Exchange (ETDEWEB)

    Bebeshko, G.I.; Afanas' eva, V.I.; Danielova, I.I.; Dmitriev, M.A.; Radchenko, A.F.

    1986-09-01

    The authors attempt to develop selective ionometric methods to determine chloride ion in waste and circulating waters from technological ore processing, containing significant amounts of sulfide ion and various flotation reagents. These waters contain practically no cations that form hard to dissolve compounds with chloride ion such as Ag/sup +/, Cu/sup +/, Hg/sup +/ or Pb/sup 2 +/. The chloride ion concentration in water varies between 10 and 100 mg/liter. Information is shown on the concentration of the main anions and flotation reagents in waters that were analyzed.

  11. Determining operating policies for a water resource system

    Science.gov (United States)

    Dagli, C. H.; Miles, J. F.

    1980-07-01

    The object of the study described in this paper was to find a method of determining operating policies for a set of four dams which are to be constructed on the Firat (Euphrates) River in Turkey. Each of the dams has an associated hydro-electric power plant, and there are requirements to supply water for irrigation, as well as maintaining river flows downstream of the dams into Syria and Iraq. The problem is thus complex and conventional stochastic models would entail an excessive amount of computation. Moreover, the set of feasible operating policies is so large that simulation cannot be considered a viable alternative. The method adopted might be described as adaptive planning (AP). At time l a forecast is made of the inflow values expected during the planning period and using these forecast values a deterministic model of the system is solved to obtain an operating policy for time l + 1. The forecast is updated and the model re-run at each successive time period to yield revised policies based on the latest available data. The solution obtained by this method for a five-year test period, using historical data, was within 0.4% of the optimal solution.

  12. Determination of Water Use Effectiveness in Hayrabolu Irrigation Scheme

    Directory of Open Access Journals (Sweden)

    A.N.Yuksel

    2005-05-01

    Full Text Available This study was conducted to determine the effectiveness of irrigation water use in HayraboluIrrigation Scheme, established in 1987 and transferred to irrigation cooperative. The study was completed intwo years in order to minimize the meteorological and environmental effects on evapotranspiration andirrigation water requirement. Irrigation application efficiency and sufficiency of farmer irrigation applicationwere investigated at 20 different farmers’ fields.Pressurized irrigation was prevailed (51 % and irrigation efficiency for sprinkler and surfaceirrigation methods were 61 and 62 %, respectively. Irrigation water losses on the scheme basis was 11,91 %.It was further determined that farmers irrigated their crops according to the phonological observation, did nottake the permissible consumption level of water content and applied insufficient water to satisfy the fieldcapacity. Among the predominantly grown crops, wheat and sunflower were not irrigated assuming that theprecipitation was sufficient to meet their demand while onion and corn were under-supplied. Generally, aneffective irrigation programme was not realised.

  13. A Possibility of Determining the Optical Peoperties of Water from the Snell-Window Image

    Science.gov (United States)

    Dolin, L. S.; Molkov, A. A.

    2017-06-01

    We develop an analytical model of the Snell window, which allows for the effects of absorption and multiple scattering of light in water. The effect of an abnormally weak dependence of the visual brightness of the Snell-window boundary on the water turbidity is revealed. This effect, along with the effect of the Snell-window boundary "blurring" because of the light scattering in water can be used to determine the absorption and scattering coefficients of water using the corresponding processing of the Snell window images. We propose and experimentally check the algorithms for determining the inherent hydrooptical characteristics from the Snell-window images using the empirical correlations between various characteristics.

  14. Nationwide water availability data for energy-water modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Tidwell, Vincent Carroll; Zemlick, Katie M.; Klise, Geoffrey Taylor

    2013-11-01

    The purpose of this effort is to explore where the availability of water could be a limiting factor in the siting of new electric power generation. To support this analysis, water availability is mapped at the county level for the conterminous United States (3109 counties). Five water sources are individually considered, including unappropriated surface water, unappropriated groundwater, appropriated water (western U.S. only), municipal wastewater and brackish groundwater. Also mapped is projected growth in non-thermoelectric consumptive water demand to 2035. Finally, the water availability metrics are accompanied by estimated costs associated with utilizing that particular supply of water. Ultimately these data sets are being developed for use in the National Renewable Energy Laboratories' (NREL) Regional Energy Deployment System (ReEDS) model, designed to investigate the likely deployment of new energy installations in the U.S., subject to a number of constraints, particularly water.

  15. DEVELOPMENT OF WATER CIRCULATION MODEL INCLUDING IRRIGATION

    Science.gov (United States)

    Kotsuki, Shunji; Tanaka, Kenji; Kojiri, Toshiharu; Hamaguchi, Toshio

    It is well known that since agricultural water withdrawal has much affect on water circulation system, accurate analysis of river discharge or water balance are difficult with less regard for it. In this study, water circulation model composed of land surface model and distributed runoff model is proposed at 10km 10km resolution. In this model, irrigation water, which is estimated with land surface model, is introduced to river discharge analysis. The model is applied to the Chao Phraya River in Thailand, and reproduced seasonal water balance. Additionally, the discharge on dry season simulated with the model is improved as a result of including irrigation. Since the model, which is basically developed from global data sets, simulated seasonal change of river discharge, it can be suggested that our model has university to other river basins.

  16. An Alternative Approach for the Determination of Soil Water Mobility

    Institute of Scientific and Technical Information of China (English)

    M.P.C.ENGLER; R.CICHOTA; Q.DE JONG VAN LIER; E.M.BLOEM; G.SPAROVEK; E. SCHNUG

    2008-01-01

    A new laboratory method was proposed to establish an easily performed standard for the determination of mobile soil water close to real conditions during the infiltration and redistribution of water in a soil.It consisted of applying a water volume with a tracer ion on top of an undisturbed ring sample on a pressure plate under a known suction or pressure head.Afterwards,soil water mobility was determined by analyzing the tracer-ion concentration in the soil sample.Soil water mobility showed to be a function of the applied water volume.No relation between soil water mobility and applied pressure head could be established with data from the present experiment.A simple one- or two-parameter equation can be fitted to the experimental data to parameterize soil water mobility as a function of applied solute volume.Sandy soils showed higher mobility than loamy soils at low values of applied solute volumes,and both sandy and loamy soils showed an almost complete mobility at high applied solute volumes.

  17. Modelling of water permeability in cementitious materials

    DEFF Research Database (Denmark)

    Guang, Ye; Lura, Pietro; van Breugel, K.

    2006-01-01

    This paper presents a network model to predict the permeability of cement paste from a numerical simulation of its microstructure. Based on a linked list pore network structure, the effective hydraulic conductivity is estimated and the fluid flow is calculated according to the Hagen-Poiseuille law....... The pressure gradient at all nodes is calculated with the Gauss elimination method and the absolute permeability of the pore network is calculated directly from Darcy's law. Finally, the permeability model is validated by comparison with direct water permeability measurements. According to this model......, the predicted permeability of hydrating cement pastes is extremely sensitive to the particle size distribution of the cement and especially to the minimum size of the cement particles. Both in simulations and experiments, the permeability of cement pastes is mainly determined by the critical diameter...

  18. Recent Experimental Advances to Determine (noble) Gases in Waters

    Science.gov (United States)

    Kipfer, R.; Brennwald, M. S.; Huxol, S.; Mächler, L.; Maden, C.; Vogel, N.; Tomonaga, Y.

    2013-12-01

    In aquatic systems noble gases, radon, and bio-geochemically conservative transient trace gases (SF6, CFCs) are frequently applied to determine water residence times and to reconstruct past environmental and climatic conditions. Recent experimental breakthroughs now enable ● to apply the well-established concepts of terrestrial noble gas geochemistry in waters to the minute water amounts stored in sediment pore space and in fluid inclusions (A), ● to determine gas exchange processes on the bio-geochemical relevant time scales of minutes - hours (B), and ● to separate diffusive and advective gas transport in soil air (C). A. Noble-gas analysis in water samples (10.1021/es401698p. [4] Mächler et al. (2012) Environ. Sci. Technol., 47, 7060-7066. [5] Huxol et al. Environ. Sci. Technol., in revision.

  19. An apparatus for determining water vapour permeability of fabrics

    Directory of Open Access Journals (Sweden)

    B. L. Saksena

    1955-04-01

    Full Text Available An apparatus for the determination of water vapour permeability (W.V.P. of fabrics is described. The fabric partitions a closed space into two compartments in which are circulated air streams having high and low water vapour pressure respectively, without any overall pressure or temperature difference. The transfer of moisture from the high to the low humidity side of the fabric is gravimetrically measured. Results of tests are given.

  20. Urban-Water Harmony model to evaluate the urban water management.

    Science.gov (United States)

    Ding, Yifan; Tang, Deshan; Wei, Yuhang; Yin, Sun

    2014-01-01

    Water resources in many urban areas are under enormous stress due to large-scale urban expansion and population explosion. The decision-makers are often faced with the dilemma of either maintaining high economic growth or protecting water resources and the environment. Simple criteria of water supply and drainage do not reflect the requirement of integrated urban water management. The Urban-Water Harmony (UWH) model is based on the concept of harmony and offers a more integrated approach to urban water management. This model calculates four dimensions, namely urban development, urban water services, water-society coordination, and water environment coordination. And the Analytic Hierarchy Process has been used to determine the indices weights. We applied the UWH model to Beijing, China for an 11-year assessment. Our findings show that, despite the severe stress inherent in rapid development and water shortage, the urban water relationship of Beijing is generally evolving in a positive way. The social-economic factors such as the water recycling technologies contribute a lot to this change. The UWH evaluation can provide a reasonable analysis approach to combine various urban and water indices to produce an integrated and comparable evaluation index. This, in turn, enables more effective water management in decision-making processes.

  1. GlobWat – a global water balance model to assess water use in irrigated agriculture

    Directory of Open Access Journals (Sweden)

    J. Hoogeveen

    2015-01-01

    Full Text Available GlobWat is a freely distributed, global soil water balance model that is used by FAO to assess water use in irrigated agriculture; the main factor behind scarcity of freshwater in an increasing number of regions. The model is based on spatially distributed high resolution datasets that are consistent at global level and calibrated against values for Internal Renewable Water Resources, as published in AQUASTAT, FAO's global information system on water and agriculture. Validation of the model is done against mean annual river basin outflows. The water balance is calculated in two steps: first a "vertical" water balance is calculated that includes evaporation from in situ rainfall ("green" water and incremental evaporation from irrigated crops. In a second stage, a "horizontal" water balance is calculated to determine discharges from river (sub-basins, taking into account incremental evaporation from irrigation, open water and wetlands ("blue" water. The paper describes methodology, input and output data, calibration and validation of the model. The model results are finally compared with other global water balance models.

  2. WATER QUALITY MODELING OF SUZHOU CREEK

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Water-quality models are important tools for improving river environment. In this paper, the project "Water Quality Modeling of the Suzhou Creek" was briefly described, including the choice and the principle of the model, the model study and methods, the calibration and verification of the stream model. A set of parameters about water environmental characteristic of the Suzhou Creek were put forward in the period of the third water dispatch experiment in 1999. It is necessary to point out that these parameters will change with the rehabilitation and construction of the Suzhou Creek.

  3. Determination of phosphorus in natural waters: A historical review.

    Science.gov (United States)

    Worsfold, Paul; McKelvie, Ian; Monbet, Phil

    2016-04-28

    The aim of this paper is to introduce a virtual special issue that reviews the development of analytical approaches to the determination of phosphorus species in natural waters. The focus is on sampling and sample treatment, analytical methods and quality assurance of the data. The export of phosphorus from anthropogenic activities (from diffuse and point sources) can result in increased primary production and eutrophication, and potentially the seasonal development of toxic algal blooms, which can significantly impact on water quality. Therefore the quantification of phosphorus species in natural waters provides important baseline data for studying aquatic phosphorus biogeochemistry, assessing ecosystem health and monitoring compliance with legislation.

  4. Modelo para a determinação do espaçamento entre desaguadouros em estradas não pavimentadas A model to determine the spacing between water outlets in unpaved roads

    Directory of Open Access Journals (Sweden)

    Nori Paulo Griebeler

    2005-06-01

    Full Text Available As estradas não pavimentadas são de fundamental importância para o desenvolvimento social e econômico do Brasil, sendo a erosão provocada pela água no leito e nas margens destas estradas um dos principais fatores para sua degradação. Neste artigo, apresenta-se um novo modelo para a determinação do espaçamento entre desaguadouros em estradas não pavimentadas e, conseqüentemente, para a redução dos problemas associados à erosão hídrica. Utilizando o modelo de ondas cinemáticas, determina-se o hidrograma de escoamento superficial no canal de drenagem da estrada e, a partir deste, é calculada a tensão provocada pelo escoamento. Sempre que a tensão cisalhante causada pelo escoamento supera a tensão crítica para cisalhamento do solo ocorre o seu desprendimento. A diferença entre essas tensões cisalhantes é multiplicada pela erodibilidade do solo e pela área em que ocorre a aplicação da tensão cisalhante para estimar a perda de solo provocada pelo escoamento. O espaçamento máximo entre desaguadouros é obtido, comparando-se a perda de solo provocada pelo escoamento com a perda de solo tolerável. O comprimento máximo do canal é aquele para o qual a perda tolerável é atingida. O modelo permite determinar o espaçamento entre desaguadouros considerando as características das áreas que contribuem para o escoamento e a resistência do solo. As simulações realizadas mostraram que o modelo é sensível às alterações na erodibilidade e na tensão crítica de cisalhamento do solo, bem como à declividade do canal, permitindo ainda que, por meio da alteração no aprofundamento tolerável para o canal, os espaçamentos possam ser ampliados ou reduzidos.Unpaved roads are essential for the economic and social development in Brazil. Water erosion is one of the key factors causing their degradation. This study developed a new model of determination of spacing between water outlets in unpaved roads. The surface runoff

  5. Water Hammer Modelling and Simulation by GIS

    OpenAIRE

    Hariri Asli, K.; Haghi,A. K.; Hariri Asli, H.; E. Sabermaash Eshghi

    2012-01-01

    This work defined an Eulerian-based computational model compared with regression of the relationship between the dependent and independent variables for water hammer surge wave in transmission pipeline. The work also mentioned control of Unaccounted-for-Water (UFW) based on the Geography Information System (GIS) for water transmission pipeline. The experimental results of laboratory model and the field test results showed the validity of prediction achieved by computational model.

  6. Hybrid Sludge Modeling in Water Treatment Processes

    OpenAIRE

    Brenda, Marian

    2015-01-01

    Sludge occurs in many waste water and drinking water treatment processes. The numeric modeling of sludge is therefore crucial for developing and optimizing water treatment processes. Numeric single-phase sludge models mainly include settling and viscoplastic behavior. Even though many investigators emphasize the importance of modeling the rheology of sludge for good simulation results, it is difficult to measure, because of settling and the viscoplastic behavior. In this thesis, a new method ...

  7. Water Hammer Modelling and Simulation by GIS

    Directory of Open Access Journals (Sweden)

    K. Hariri Asli

    2012-01-01

    Full Text Available This work defined an Eulerian-based computational model compared with regression of the relationship between the dependent and independent variables for water hammer surge wave in transmission pipeline. The work also mentioned control of Unaccounted-for-Water (UFW based on the Geography Information System (GIS for water transmission pipeline. The experimental results of laboratory model and the field test results showed the validity of prediction achieved by computational model.

  8. RAPID DETERMINATION OF {sup 210} PO IN WATER SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.

    2013-05-22

    A new rapid method for the determination of {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that can be used for emergency response or routine water analyses. If a radiological dispersive device (RDD) event or a radiological attack associated with drinking water supplies occurs, there will be an urgent need for rapid analyses of water samples, including drinking water, ground water and other water effluents. Current analytical methods for the assay of {sup 210}Po in water samples have typically involved spontaneous auto-deposition of {sup 210}Po onto silver or other metal disks followed by counting by alpha spectrometry. The auto-deposition times range from 90 minutes to 24 hours or more, at times with yields that may be less than desirable. If sample interferences are present, decreased yields and degraded alpha spectrums can occur due to unpredictable thickening in the deposited layer. Separation methods have focused on the use of Sr Resin, often in combination with 210Pb analysis. A new rapid method for {sup 210}Po in water samples has been developed at the Savannah River National Laboratory (SRNL) that utilizes a rapid calcium phosphate co-precipitation method, separation using DGA Resin (N,N,N,N-tetraoctyldiglycolamide extractant-coated resin, Eichrom Technologies or Triskem-International), followed by rapid microprecipitation of {sup 210}Po using bismuth phosphate for counting by alpha spectrometry. This new method can be performed quickly with excellent removal of interferences, high chemical yields and very good alpha peak resolution, eliminating any potential problems with the alpha source preparation for emergency or routine samples. A rapid sequential separation method to separate {sup 210} Po and actinide isotopes was also developed. This new approach, rapid separation with DGA Resin plus microprecipitation for alpha source preparation, is a significant advance in radiochemistry for the rapid

  9. Applying the WEAP Model to Water Resource

    DEFF Research Database (Denmark)

    Gao, Jingjing; Christensen, Per; Li, Wei

    Water resources assessment is a tool to provide decision makers with an appropriate basis to make informed judgments regarding the objectives and targets to be addressed during the Strategic Environmental Assessment (SEA) process. The study shows how water resources assessment can be applied in SEA...... in assessing the effects on water resources using a case study on a Coal Industry Development Plan in an arid region in North Western China. In the case the WEAP model (Water Evaluation And Planning System) were used to simulate various scenarios using a diversity of technological instruments like irrigation...... efficiency, treatment and reuse of water. The WEAP model was applied to the Ordos catchment where it was used for the first time in China. The changes in water resource utilization in Ordos basin were assessed with the model. It was found that the WEAP model is a useful tool for water resource assessment...

  10. Multi-Phase Modeling of Rainbird Water Injection

    Science.gov (United States)

    Vu, Bruce T.; Moss, Nicholas; Sampson, Zoe

    2014-01-01

    This paper describes the use of a Volume of Fluid (VOF) multiphase model to simulate the water injected from a rainbird nozzle used in the sound suppression system during launch. The simulations help determine the projectile motion for different water flow rates employed at the pad, as it is critical to know if water will splash on the first-stage rocket engine during liftoff.

  11. Determination of Carboxylic Acids and Water-soluble Inorganic Ions ...

    African Journals Online (AJOL)

    NICO

    radiation balance.4,5 Major water-soluble inorganic ions are associated with ... central area and major road systems and possible aerosol sources include biomass ..... Tanzania than at European rural sites32 and Asia.33,34. To determine the ...

  12. WATER LAW AND MODEL OF RESPONSIBLE WATER USAGE

    Directory of Open Access Journals (Sweden)

    Dmitri Olegovitch Sivakov

    2017-03-01

    Full Text Available As it is known, the water law regulates dynamic social relationships concerning study, usage and protection of water objects, as well as their transformation. The water law explicitly regulates water economic activities. The regulatory method of the water law has a mixed nature and thus is not distinctive. It predetermines in some cases equality and independence of subjects of relationships (water usage agreement and in other – power and submission (permissive nature of water usage. The aim of the publication is to promote scientific ideas about the fate of the water law in order to make a further polygonal and productive discussion in which the reader is invited to participate. Scientific novelty. In 2016 the monograph of D.O. Sivakov “Water law: dynamics, problems, perspectives: monograph” (second edition, reviewed and updated. Moscow: Stolitsa, 2016. 540 p. was published. In 2017 the author reconsidered some conclusions of his monograph and applied scientific achievements of theory of state and law in water sphere. In accordance with this, it is important to mention research of Petrov D.E. related to issues of differentiation and integration of structural formations of Russian legal system. The scientific novelty of the article includes the synthesis of ideas of the monograph and some achievements of theory of state and law. Methods of research. The author of the article relies on some collective and individual monographic studies in the sphere of theory of state and law, natural resource law, arctic law, financial law. Basic results of research. The author promotes the model of responsible water usage. This model shall be based not on the unstable balance of economic and environmental interests (which shall practically lead to the domination of economic interests, but on the obligatory combination of economic activities with technologies, ensuring maximal preservation of water resources. Responsible water usage shall mean a system of

  13. Role of Water Resources in Determining Spatial Planning of Region

    Directory of Open Access Journals (Sweden)

    Alif Noor Anna

    2004-01-01

    Full Text Available In planning a spatial order in a territory , it is necessary to take acount of three aspects of natural resources, human resources, and living environment. Based on the reality, so it is necessary  to think of two sides: potential human resources and environment and human resources. One of the resources that is absolutely needed by creatures is water. Concerning the spatial order, the water is greatly needed in a variety of life. As the other resources, the reserve of the water also get limited. Because of its limitation, it is necessary to control the potential water sources in a territory before determining a design of good spatial order. It means that in planning the spatial order must be based on the rule and regulation of preserving its resource.

  14. Nambe Pueblo Water Budget and Forecasting model.

    Energy Technology Data Exchange (ETDEWEB)

    Brainard, James Robert

    2009-10-01

    This report documents The Nambe Pueblo Water Budget and Water Forecasting model. The model has been constructed using Powersim Studio (PS), a software package designed to investigate complex systems where flows and accumulations are central to the system. Here PS has been used as a platform for modeling various aspects of Nambe Pueblo's current and future water use. The model contains three major components, the Water Forecast Component, Irrigation Scheduling Component, and the Reservoir Model Component. In each of the components, the user can change variables to investigate the impacts of water management scenarios on future water use. The Water Forecast Component includes forecasting for industrial, commercial, and livestock use. Domestic demand is also forecasted based on user specified current population, population growth rates, and per capita water consumption. Irrigation efficiencies are quantified in the Irrigated Agriculture component using critical information concerning diversion rates, acreages, ditch dimensions and seepage rates. Results from this section are used in the Water Demand Forecast, Irrigation Scheduling, and the Reservoir Model components. The Reservoir Component contains two sections, (1) Storage and Inflow Accumulations by Categories and (2) Release, Diversion and Shortages. Results from both sections are derived from the calibrated Nambe Reservoir model where historic, pre-dam or above dam USGS stream flow data is fed into the model and releases are calculated.

  15. STORM WATER MANAGEMENT MODEL (SWMM) MODERNIZATION

    Science.gov (United States)

    The U.S. Environmental Protection Agency's Water Supply and Water Resources Division in partnership with the consulting firm of CDM to redevelop and modernize the Storm Water Management Model (SWMM). In the initial phase of this project EPA rewrote SWMM's computational engine usi...

  16. DETERMINATION OF WATER FLOW CONNECTION IN WATER SUPPLY SYSTEM IN PUBLIC BUILDINGS

    OpenAIRE

    2016-01-01

    An important factor for selection of main water meters is a precise determination of design flow, value of “nieprzewyższenia”. Presently, technical norms, on which determination of design flow for diameter selection of waterworks selection and consequently water meters selection are based, are no reliable in relation to the actual flow. This gives arguments to ascertain that harmonized standards do not meet Polish conditions and it requires correction. The article presents the method of de...

  17. Hydraulic modelling of drinking water treatment plant operations

    Directory of Open Access Journals (Sweden)

    K. J. Borger

    2008-10-01

    Full Text Available For a drinking water treatment plant simulation, water quality models, a hydraulic model, a process-control model, an object model, data management, training and decision-support features and a graphic user interface have been integrated. The integration of a hydraulic model in the simulator is necessary to correctly determine the division of flows over the plant's lanes and, thus, the flow through the individual treatment units, based on valve positions and pump speeds. The flow through a unit is one of the most important parameters in terms of a unit's effectiveness. In the present paper, a new EPAnet library is presented with the typical hydraulic elements for drinking water treatment processes. Using this library, a hydraulic model was set up and validated for the drinking water treatment plant Harderbroek.

  18. Integrated water resources modelling for assessing sustainable water governance

    Science.gov (United States)

    Skoulikaris, Charalampos; Ganoulis, Jacques; Tsoukalas, Ioannis; Makropoulos, Christos; Gkatzogianni, Eleni; Michas, Spyros

    2015-04-01

    Climatic variations and resulting future uncertainties, increasing anthropogenic pressures, changes in political boundaries, ineffective or dysfunctional governance of natural resources and environmental degradation are some of the most fundamental challenges with which worldwide initiatives fostering the "think globally, act locally" concept are concerned. Different initiatives target the protection of the environment through sustainable development; Integrated Water Resources Management (IWRM) and Transboundary Water Resources Management (TWRM) in the case of internationally shared waters are frameworks that have gained wide political acceptance at international level and form part of water resources management planning and implementation on a global scale. Both concepts contribute in promoting economic efficiency, social equity and environmental sustainability. Inspired by these holistic management approaches, the present work describes an effort that uses integrated water resources modelling for the development of an integrated, coherent and flexible water governance tool. This work in which a sequence of computer based models and tools are linked together, aims at the evaluation of the sustainable operation of projects generating renewable energy from water as well as the sustainability of agricultural demands and environmental security in terms of environmental flow under various climatic and operational conditions. More specifically, catchment hydrological modelling is coupled with dams' simulation models and thereafter with models dedicated to water resources management and planning,while the bridging of models is conducted through geographic information systems and custom programming tools. For the case of Mesta/Nestos river basin different priority rules in the dams' operational schedule (e.g. priority given to power production as opposed to irrigation needs and vice versa), as well as different irrigation demands, e.g. current water demands as opposed to

  19. Modelling of Buckingham Canal water quality.

    Science.gov (United States)

    Abbasi, S A; Khan, F I; Sentilvelan, K; Shabudeen, A

    2002-10-01

    The paper presents a case study of the modelling of the water quality of a canal situated in a petrochemical industrial complex, which receives wastewaters from Madras Refineries Limited (MRL), and Madras Fertilizers Limited (MFL). The canal well known Buckingham Canal which passes through Chennai (Madras), India has been modelled using the software QUAL2E-UNCAS. After testing and validation of the model, simulations have been carried out. The exercise enables forecasting the impacts of different seasons, base flows, and waste water inputs on the water quality of the Buckingham Canal. It also enables development of water management strategies.

  20. Determining the Most Appropriate Classification Methods for Water Quality

    Science.gov (United States)

    Gürsoy, Önder

    2016-10-01

    Assessing water resources’ quality and also monitoring them have attracted lots of attention in the recent years. Remote sensing has been growing widely in the last decade and its resources are very usable when it comes to water resources management. In this study, by using remote sensing technology, satellite images that have 350 to 1050 nanometres wavelength band sensors are used to determine the quality of the Kizilirmak River's water. Through the river's resources, ground based spectral measurements are made to identify the quality differences of the water at the test spots that have been determined before. In this context at Imranli, where the river contacts civilization for the first time, which is located in Sivas city of Turkey, samples are gathered in order to do ground based spectroradiometer measurements. These samples are gathered simultaneously with the image acquiring time of CHRIS Proba satellite. Spectral signatures that are obtained from ground measurements are used as reference data in order to classify CHRIS Proba satellite's hyperspectral images over the study area. Satellite images are classified based on Chemical Oxygen Demand (COD), Turbidity and Electrical Conductivity (EC) attributes. As a result, interpretations obtained from classified CHRIS Proba satellite hyperspectral images of the study area are presented. Spectras are readied for Matched Filtering and Spectral Angle Mapper methods for determining the best classification method.

  1. Systems modelling for effective mine water management

    Energy Technology Data Exchange (ETDEWEB)

    Cote, C.M.; Moran, C.J.; Hedemann, C.J.; Koch, C. [University of Queensland, Brisbane, Qld. (Australia)

    2010-12-15

    Concerns about the difficulties in securing water have led the Australian coal mining industry to seek innovative ways to improve its water management and to adopt novel strategies that will lead to less water being used and more water being reused. Simulation tools are essential to assess current water management performance and to predict the efficiency of potential strategies. As water systems on coal mines are complex and consist of various inter-connected elements, a systems approach was selected, which views mine site water management as a system that obtains water from various sources (surface, groundwater), provides sufficient water of suitable quality to the mining tasks (coal beneficiation, dust suppression, underground operations) and maintains environmental performance. In this paper, the model is described and its calibration is illustrated. The results of applying the model for the comparison of the water balances of 7 coal mines in the northern Bowen Basin (Queensland, Australia) are presented. The model is used to assess the impact of applying specific water management strategies. Results show that a simple systems model is an appropriate tool for assessing site performance, for providing guidance to improve performance through strategic planning, and for guiding adoption of site objectives.

  2. Model for radionuclide transport in running waters

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Karin; Elert, Mark [Kemakta Konsult AB, Stockholm (Sweden)

    2005-11-15

    Two sites in Sweden are currently under investigation by SKB for their suitability as places for deep repository of radioactive waste, the Forsmark and Simpevarp/Laxemar area. As a part of the safety assessment, SKB has formulated a biosphere model with different sub-models for different parts of the ecosystem in order to be able to predict the dose to humans following a possible radionuclide discharge from a future deep repository. In this report, a new model concept describing radionuclide transport in streams is presented. The main difference from the previous model for running water used by SKB, where only dilution of the inflow of radionuclides was considered, is that the new model includes parameterizations also of the exchange processes present along the stream. This is done in order to be able to investigate the effect of the retention on the transport and to be able to estimate the resulting concentrations in the different parts of the system. The concentrations determined with this new model could later be used for order of magnitude predictions of the dose to humans. The presented model concept is divided in two parts, one hydraulic and one radionuclide transport model. The hydraulic model is used to determine the flow conditions in the stream channel and is based on the assumption of uniform flow and quasi-stationary conditions. The results from the hydraulic model are used in the radionuclide transport model where the concentration is determined in the different parts of the stream ecosystem. The exchange processes considered are exchange with the sediments due to diffusion, advective transport and sedimentation/resuspension and uptake of radionuclides in biota. Transport of both dissolved radionuclides and sorbed onto particulates is considered. Sorption kinetics in the stream water phase is implemented as the time scale of the residence time in the stream water probably is short in comparison to the time scale of the kinetic sorption. In the sediment

  3. A Theoretical Model of Water and Trade

    Science.gov (United States)

    Dang, Q.; Konar, M.; Reimer, J.; Di Baldassarre, G.; Lin, X.; Zeng, R.

    2015-12-01

    Water is an essential factor of agricultural production. Agriculture, in turn, is globalized through the trade of food commodities. In this paper, we develop a theoretical model of a small open economy that explicitly incorporates water resources. The model emphasizes three tradeoffs involving water decision-making that are important yet not always considered within the existing literature. One tradeoff focuses on competition for water among different sectors when there is a shock to one of the sectors only, such as trade liberalization and consequent higher demand for the product. A second tradeoff concerns the possibility that there may or may not be substitutes for water, such as increased use of sophisticated irrigation technology as a means to increase crop output in the absence of higher water availability. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using products. A number of propositions are proven. For example, while trade liberalization tends to increase water use, increased pressure on water supplies can be moderated by way of a tax that is derivable with observable economic phenomena. Another example is that increased riskiness of water availability tends to cause water users to use less water than would be the case under profit maximization. These theoretical model results generate hypotheses that can be tested empirically in future work.

  4. Building Water Models, A Different Approach

    CERN Document Server

    Izadi, Saeed; Onufriev, Alexey V

    2014-01-01

    Simplified, classical models of water are an integral part of atomistic molecular simulations, especially in biology and chemistry where hydration effects are critical. Yet, despite several decades of effort, these models are still far from perfect. Presented here is an alternative approach to constructing point charge water models - currently, the most commonly used type. In contrast to the conventional approach, we do not impose any geometry constraints on the model other than symmetry. Instead, we optimize the distribution of point charges to best describe the "electrostatics" of the water molecule, which is key to many unusual properties of liquid water. The search for the optimal charge distribution is performed in 2D parameter space of key lowest multipole moments of the model, to find best fit to a small set of bulk water properties at room temperature. A virtually exhaustive search is enabled via analytical equations that relate the charge distribution to the multipole moments. The resulting "optimal"...

  5. An improved shallow water equation model for water animation

    Science.gov (United States)

    Ai, Mingjing; Du, Anding; Xu, Han; Niu, Jianwei

    2017-03-01

    In this paper, we proposed a new scheme for simulating water flows under shallow water assumption. The method is an extension of traditional shallow water equations. In contrast to traditional methods, we design a dynamic coordinate system for modeling in order to efficiently simulate water flows. Within this system, we derive our specialized shallow water equations directly from the Navier-Stockes equation. At the same time, we develop an implicit mechanism for solving the advection term and a vector projection operator for solving the external forces acting on water. We also present a two-way coupling method for simulating the interaction between water and rigid solid. The experimental results show that the proposed scheme can achieve a more realistic and accurate water model compared with the traditional methods, especially when the solid surfaces are too steep. Also we demonstrate the efficiency of our method in several scenes, all run at least 50 frames per second on average which allows real-time simulation.

  6. Shallow water modeling of Antarctic Bottom Water crossing the equator

    Science.gov (United States)

    Choboter, Paul F.; Swaters, Gordon E.

    2004-03-01

    The dynamics of abyssal equator-crossing flows are examined by studying simplified models of the flow in the equatorial region in the context of reduced-gravity shallow water theory. A simple "frictional geostrophic" model for one-layer cross-equatorial flow is described, in which geostrophy is replaced at the equator by frictional flow down the pressure gradient. This model is compared via numerical simulations to the one-layer reduced-gravity shallow water model for flow over realistic equatorial Atlantic Ocean bottom topography. It is argued that nonlinear advection is important at key locations where it permits the current to flow against a pressure gradient, a mechanism absent in the frictional geostrophic model and one of the reasons this model predicts less cross-equatorial flow than the shallow water model under similar conditions. Simulations of the shallow water model with an annually varying mass source reproduce the correct amplitude of observed time variability of cross-equatorial flow. The time evolution of volume transport across specific locations suggests that mass is stored in an equatorial basin, which can reduce the amplitude of time dependence of fluid actually proceeding into the Northern Hemisphere as compared to the amount entering the equatorial basin. Observed time series of temperature data at the equator are shown to be consistent with this hypothesis.

  7. What determines the calcium concentration of speleothem-forming drip waters?

    Science.gov (United States)

    Baker, Andy; Flemons, Ingrid; Andersen, Martin S.; Coleborn, Katie; Treble, Pauline C.

    2016-08-01

    Cave drip water calcium ion concentration is a primary determinant of speleothem deposition and growth rate. The factors that determine drip water calcium ion concentrations are the soil and vadose zone CO2 concentrations, and the hydrogeochemical evolution of the water from soil to cave. Here, we use a systematic literature review of cave drip water calcium concentrations, combined with PHREEQC equilibrium modelling, to investigate the global relationship between calcium concentration and surface climate. Our results are discussed in the context of understanding the climatic and environmental controls on drip water calcium concentration, speleothem growth rates and proxies of past climate and environmental change. We use an empirical, global soil CO2 concentration-temperature relationship to derive PHREEQC modelled cave drip water calcium concentrations. The global mean modelled drip water calcium concentration is close to that observed, but it over-predicts at high and low temperatures, and significantly under-predicts at temperate conditions. We hypothesise that closed system hydrochemical evolution due to water saturation is an important control on carbonate dissolution at colder temperatures. Under warmer conditions, for example temperate climates with a dry and hot or warm summer, seasonally-limited water availability can lead to: microbial and root respiration; wildfire; and prior calcite precipitation, all of which limit drip water calcium concentrations. In temperate climates with no dry season, higher CO2 concentrations than modelled from soil values are necessary to explain the observed drip water calcium values, which we propose is from an additional source of CO2 from microbial activity and root respiration in the vadose zone during open system hydrochemical evolution.

  8. Qualitative and quantitative determination of water in airborne particulate matter

    Directory of Open Access Journals (Sweden)

    S. Canepari

    2012-10-01

    Full Text Available This paper describes the optimization and validation of a new simple method for the quantitative determination of water in atmospheric particulate matter (PM. The analyses are performed by using a coulometric Karl-Fisher system equipped with a controlled heating device; different water contributions are separated by the application of an optimized thermal ramp (three heating steps: 50–120 °C, 120–180 °C, 180–250 °C.

    The analytical performance of the method was verified by using standard materials containing 5.55% and 1% by weight of water. The recovery was greater than 95%; the detection limit was about 20 μg. The method was then applied to NIST reference materials (NIST1649a, urban particulate matter and to real PM10 samples collected in different geographical areas. In all cases the repeatability was satisfactory (10–15%.

    When analyzing the reference material, the separation of four different types of water was obtained. In real PM10 samples the amount of water and its thermal profile differed as a function of the chemical composition of the dust. Mass percentages of 3–4% of water were obtained in most samples, but values up to about 15% were reached in areas where the chemical composition of PM is dominated by secondary inorganic ions and organic matter. High percentages of water were also observed in areas where PM is characterized by the presence of desert dust.

    A possible identification of the quality of water released from the samples was tried by applying the method to some hygroscopic compounds that are likely contained in PM (pure SiO2, Al2O3, ammonium salts, carbohydrates and dicarboxylic acids and by comparing the results with those obtained from field samples.

  9. Practical Guidelines for Water Percolation Capacity Determination of the Ground

    Directory of Open Access Journals (Sweden)

    Mihael Brenčič

    2011-06-01

    Full Text Available Determination of water infiltration capacity of ground soils and rocks represents important part of design and construction procedures of the facilities for the infiltration of clean precipitation water. With their help percolation capacity of ground as well as response of the infiltration facilities to the inflowing precipitation water is estimated.Comparing to other in situ hydrogeological tests they can be understood as simple. However, in every day’s practiceseveral problems during their on site application and desk interpretation can arise. Paper represents review of existingpractical engineering procedures during the performance of percolation tests. Procedures are described for the borehole and shaft percolation tests execution and calculation theory for stationary and non‑stationary percolation tests are given. Theory is illustrated with practical exercises. Interpretations of typical departures from theoretical presumptions according to Hvorslev test of non-stationary test are illustrated.

  10. Simulation method for determining biodegradation in surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Schoeberl, P.; Guhl, W. [Henkel KGaA, Duesseldorf (Germany). Hauptabteilung Oekologie; Scholz, N. [OXENO GmbH, Marl (Germany); Taeger, K. [BASF AG, Ludwigshafen am Rhein (Germany)

    1998-07-01

    OECD guidelines and EU directives on the biological testing of chemicals contain no methods able to simulate biodegradation in surface waters. The surface water simulation method presented in this paper is suitable for closing this gap. The species in the autochthonous biocoenosis used in the method form part of the food web in natural surface waters. The microbial degradation activity measured by the half-life is comparable with that in surface waters. The degrees of degradation measured in this surface water simulation method can be applied to natural surface waters. (orig.) [Deutsch] Die OECD- und EU-Richtlinien zur biologischen Pruefung von Chemikalien enthalten kein Verfahren, mit dem der biologische Abbau in Fliessgewaessern simuliert werden kann. Das in dieser Arbeit vorgestellte Fliessgewaesser-Simulationsmodell ist geeignet, diese Luecke zu schliessen. Die Arten der autochthonen Biocoenose des Modells sind Glieder im Nahrungsnetz natuerlicher Fliessgewaesser. Die an der Halbwertszeit gemessene mikrobielle Abbauaktivitaet ist mit derjenigen in Fliessgewaessern vergleichbar. Die im Fliessgewaesser-Simulationsmodell gemessenen Abbaugrade sind auf natuerliche Fliessgewaesser uebertragbar. (orig.)

  11. Flood Water Model Logan K. kuiper

    Science.gov (United States)

    Kuiper, L. K.

    2013-05-01

    A mathematical model is developed to simulate flood water movement. Specifically, the model applies to situations where water depth is much smaller than the width or length of the water body, and resistance to flow from obstructions such as trees and structures is minimal. The model is applicable to many situations and in some cases may be able to suggest flood alleviation procedures. The derivation of the discretized form of the time dependant nonlinear equation governing the flow is based upon water conservation and the ability to approximate water flow rate (L2/T) as a function of the gradient of water surface elevation and water depth using the Manning equation. The flow equation is discretized using four sided finite elements. The resulting set of simultaneous nonlinear equations is solved iteratively using a conjugate gradient solver. To check for model programming error, a simple problem with constant water depth and constant water surface elevation gradient is checked against the Manning equation. An application of the model to a situation similar to the 2010 flood in northern Belize is ongoing.

  12. Determination of Ammonium Ion in Lake Water by Voltammetry

    Institute of Scientific and Technical Information of China (English)

    Wu Yun-hua; Fei Jun-jie; Dang Xue-ping; Hu Sheng-shui

    2004-01-01

    An electroanalytical method for the determination of armonium ion using a platinized platinum electrode is described. Under optimized analytical conditions, the linear range of the calibration graphs for ammonium ion is 3. 0×10(-5)-5.0×10-3 mol·L-1.The Method has been applide to the determination of ammonium ion in lake water samples and recoveries of 100%-103%0 are obtained. The results obtained are found to be in good agreement with spectrophotometric results.

  13. Spectrophotometric Determination of Fenpropathrin in its Formulations and Water Samples

    OpenAIRE

    B. Krishna Priya; Subrahmanyam, P.; Dakshayani, K.; P. Chiranjeevi

    2007-01-01

    Novel spectrophotometric methods were developed for the determination of fenpropathrin in insecticidal formulations and water samples. The methods were based on the hydrolysis of fenpropathrin with ethanolic KOH to form 3-phenoxy benzaldehyde. The resultant aldehyde group was condensed with anthranilic acid in presence of basic medium to form yellowish red color product having λmax of 485 nm or condensed with 2-chloro phenyl hydrazine to form pink color product having λmax of 557 nm. The colo...

  14. Modeling Water Shortage Management Using an Object-Oriented Approach

    Science.gov (United States)

    Wang, J.; Senarath, S.; Brion, L.; Niedzialek, J.; Novoa, R.; Obeysekera, J.

    2007-12-01

    As a result of the increasing global population and the resulting urbanization, water shortage issues have received increased attention throughout the world . Water supply has not been able to keep up with increased demand for water, especially during times of drought. The use of an object-oriented (OO) approach coupled with efficient mathematical models is an effective tool in addressing discrepancies between water supply and demand. Object-oriented modeling has been proven powerful and efficient in simulating natural behavior. This research presents a way to model water shortage management using the OO approach. Three groups of conceptual components using the OO approach are designed for the management model. The first group encompasses evaluation of natural behaviors and possible related management options. This evaluation includes assessing any discrepancy that might exist between water demand and supply. The second group is for decision making which includes the determination of water use cutback amount and duration using established criteria. The third group is for implementation of the management options which are restrictions of water usage at a local or regional scale. The loop is closed through a feedback mechanism where continuity in the time domain is established. Like many other regions, drought management is very important in south Florida. The Regional Simulation Model (RSM) is a finite volume, fully integrated hydrologic model used by the South Florida Water Management District to evaluate regional response to various planning alternatives including drought management. A trigger module was developed for RSM that encapsulates the OO approach to water shortage management. Rigorous testing of the module was performed using historical south Florida conditions. Keywords: Object-oriented, modeling, water shortage management, trigger module, Regional Simulation Model

  15. Water-vortex-stabilized electric arc: III. Radial energy transport, determination of water-vapour-boundary and arc performance

    Science.gov (United States)

    Jenista, Jirí

    2003-12-01

    This paper is concerned with numerical modelling of an electric arc stabilized by a water vortex. The two-dimensional axisymmetric model presented includes the arc discharge area between the cathode and the outlet nozzle of the water plasma torch. The aims of the numerical simulations are: (1) to assess the influence of radial position of the water-vapour-boundary in the discharge chamber on arc performance and overall radial energy transport within the arc; (2) to determine the most probable mass flow rates and radii of the water-vapour-boundary in the discharge chamber for a prescribed current; (3) to demonstrate arc performance for two radiation models involved; and (4) to estimate validity of local thermodynamic equilibrium (LTE) conditions within the arc column. The rate of evaporation of water is calculated from the conduction and radiation heat fluxes at the water vapour surface for the specified mass flow rate. The behaviour of such an arc has been studied for a range of current 300-600 A. It is shown that changes of bulk magnitudes of different terms in the momentum and energy equations within the arc column as a function of arc radius enable us to reveal transitions of temperature and velocity fields from one steady state to a qualitatively different one. The best fit between experiment and numerical simulation for all currents exists for the mean arc radius ~3.3 mm. Deviations from LTE within the arc column are estimated with the criteria for kinetic equilibrium and spatial temperature gradients.

  16. Modelling proton transfer in water molecule chains

    CERN Document Server

    Korzhimanov, Artem; Shutova, Tatiana; Samuelsson, Goran

    2011-01-01

    The process of protons transport in molecular water chains is of fundamental interest for many biological systems. Although many features of such systems can be analyzed using large-scale computational modeling, other features are better understood in terms of simplified model problems. Here we have tested, analytically and numerically, a model describing the classical proton hopping process in molecular water chains. In order to capture the main features of the proton hopping process in such molecular chains, we use a simplified model for our analysis. In particular, our discrete model describes a 1D chain of water molecules situated in an external protein channel structure, and each water molecule is allowed to oscillate around its equilibrium point in this system, while the protons are allowed to move along the line of neighboring oxygen atoms. The occurrence and properties of nonlinear solitary transport structures, allowing for much faster proton transport, are discussed, and the possible implications of...

  17. Determination of Water Content of Water-soluble Paints by Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    顾润南; 钦维民; 肖舸

    2003-01-01

    This paper describes the determination of water content of water-soluble paints by gas chromatography. The water in paints is extracted by dimethyl formamide (DMF) as a solvent.Isopropanol is used as an internal standard. The mixture is separated by low-speed centrifugation.Then a 1-uL sample of the supernatant from the prepared solution is injected into the gas chromatograph. The water content is determined by internal standard calibration curve. The rate of recovery of added standard of this method is more than 98%. Relative mean deviation is less than 3‰.The linearity of calibration curve is good and relativity coefficient is higher than 0.998.

  18. The water kefir grain inoculum determines the characteristics of the resulting water kefir fermentation process.

    Science.gov (United States)

    Laureys, D; De Vuyst, L

    2017-03-01

    To investigate the influence of the water kefir grain inoculum on the characteristics of the water kefir fermentation process. Three water kefir fermentation processes were started with different water kefir grain inocula and followed as a function of time regarding microbial species diversity, community dynamics, substrate consumption profile and metabolite production course. The inoculum determined the water kefir grain growth, the viable counts on the grains, the time until total carbohydrate exhaustion, the final metabolite concentrations and the microbial species diversity. There were always 2-10 lactic acid bacterial cells for every yeast cell and the majority of these micro-organisms was always present on the grains. Lactobacillus paracasei, Lactobacillus hilgardii, Lactobacillus nagelii and Saccharomyces cerevisiae were always present and may be the key micro-organisms during water kefir fermentation. Low water kefir grain growth was associated with small grains with high viable counts of micro-organisms, fast fermentation and low pH values, and was not caused by the absence of exopolysaccharide-producing lactic acid bacteria. The water kefir grain inoculum influences the microbial species diversity and characteristics of the fermentation process. A select group of key micro-organisms was always present during fermentation. This study allows a rational selection of a water kefir grain inoculum. © 2016 The Society for Applied Microbiology.

  19. Modelling stable water isotopes: Status and perspectives

    Directory of Open Access Journals (Sweden)

    Werner M.

    2010-12-01

    Full Text Available Modelling of stable water isotopes H2 18O and HDO within various parts of the Earth’s hydrological cycle has clearly improved our understanding of the interplay between climatic variations and related isotope fractionation processes. In this article key principles and major research results of stable water isotope modelling studies are described. Emphasis is put on research work using explicit isotope diagnostics within general circulation models as this highly complex model setup bears many resemblances with studies using simpler isotope modelling approaches.

  20. Cache County Water Demand/Supply Model

    OpenAIRE

    Hughes, Trevor C.; Norby, Gregory J.; Thyagarajan, Laxman

    1996-01-01

    This report descibes a municipal water demand forecasting model for use in areas of mixed rural and urban housing types. A series of residential demand functions were derived which forecast water demand based on the ype and density of housing and season. Micro sampling techniques were used to correlate water use data and explanatory variable data for low, medium, and high density housing. The demand functions were...

  1. On determining field water capacity and available water in uniform and layered soil profiles: Critical accounts and Proposals

    Science.gov (United States)

    Ceres, F.; Chirico, G. B.; Romano, N.

    2009-04-01

    Field water capacity and available water concepts are major agronomic parameters widely used for irrigation management, especially in Mediterranean zones facing with shortage of water. However, their definitions are still under discussion among scientists and practitioners. Field water capacity is often determined using empirical relationships (e.g. pedotransfer functions) or from water retention points obtained in the laboratory, thus underplaying or even ignoring the important role exerted by the actual evolution of water redistribution processes in a soil profile, especially if it is a layered one. An objective and replicable method for determining the field water capacity requires monitoring a water redistribution process evolving in a soil profile thoroughly wetted by a preliminary infiltration phase. Accordingly, in this study free drainage processes in soil profiles have been simulated by applying the numerical model developed by Romano et al. (1998) and verified by Brunone et al. (2003). This model solves Richards' equation by applying the Crank-Nicolson finite difference technique and uses a numerical algorithm specifically designed in case of layered soils for calculating the hydraulic conductivity between soil layers. In addition, to ensure a good correspondence between the analyses performed and actual situations, an extensive database of uniform and layered soil profiles have been employed. Outcome from the scenarios on uniform soils have shown that soil water content values under the condition of field capacity do not match water content values obtained from water retention point measured at preselected matric pressure head. Similar results have been obtained when using retention data points retrieved from the use of well-established pedotransfer functions (such as the HYPRES-PTF). In case of layered soil profiles, which actually represent the rule rather than an exception, the layer sequence and reciprocal differences in the soil hydraulic properties

  2. DETERMINATION OF PHTHALATES FROM BOTTLED WATER BY GC-MS

    Directory of Open Access Journals (Sweden)

    IRINA DUMITRAȘCU

    2012-03-01

    Full Text Available Determination of phthalates from bottled water by GC-MS. Phthalates are ubiquitous pollutants in the environment, due to their widespread use in the last years. These compounds are used principally as plasticizers, to impact flexibility, workability and durability to polymers but they can also be found in products such as paints, adhesives, inks and cosmetics. Phthalates are not chemically bounded to polymers; hence they are easily released and migrate into foods, beverages and drinking water from the packaging or bottling materials or manufacturing processes. This process accelerates as plastic products age and break down. With respect to their endocrine disrupting potential, phthalates such as benzyl butyl phthalate (BBP, di-butyl phthalate (DBP and di-isobutyl phthalate (DIBP have been found to elicit estrogenic responses in in vitro assays. It is possible that phthalates are a contributory factor to endocrine-mediated adverse effects observed in wildlife and humans over the past few decades. In this experiment we have analyzed the phthalates from different bottled waters purchased from the market. Determination by gas chromatography in combination with mass spectrometry detector (GC–MS in electronic ionization mode (EI with selected-ion monitoring (SIM acquisition method (GC–MS (EI–SIM has been carried out. Methods have been developed for both qualitative and quantitative analysis of phthalates. The base peak (m/z = 149 of all the phthalates was selected for the screening studies. The characteristic ions of each compound were chosen for quantitative studies.

  3. Determination of inorganic anions in papermaking waters by ion chromatography

    Directory of Open Access Journals (Sweden)

    DARJA ŽARKOVIĆ

    2009-03-01

    Full Text Available A suppressed ion chromatography (IC method for the determination of inorganic anions in process water from paperboard production was developed and validated. Common inorganic anions (Cl-, NO3-, PO43- and SO42- were detected in fresh and process water samples collected from a paperboard production system at 16 characteristic points. It was shown that the use of an IonPac®-AS14 column under isocratic conditions with Na2CO3/NaHCO3 as the eluent and a suppression device proved to be a reliable analytical solution for the separation of the inorganic anions present in papermaking waters. This IC method is quite satisfactory concerning selectivity and sensitivity, and enables the determination of several inorganic anions over a wide concentration range. According to the obtained results, the total amount of analyzed inorganic anions was below 0.1 g/L, i.e., below the critical value which may trigger operational problems in paper production.

  4. Numerical modeling of water waves

    CERN Document Server

    Lin, Pengzhi

    2008-01-01

    Modelling large-scale wave fields and their interaction with coastal and offshore structures has become much more feasible over the last two decades with increases in computer speeds. Wave modelling can be viewed as an extension of wave theory, a mature and widely published field, applied to practical engineering through the use of computer tools. Information about the various wave models which have been developed is often widely scattered in the literature, and consequently this is one of the first books devoted to wave models and their applications. At the core of the book is an introduction to various types of wave models. For each model, the theoretical assumptions, the application range, and the advantages and limitations are elaborated. The combined use of different wave models from large-scale to local-scale is highlighted with a detailed discussion of the application and matching of boundary conditions. At the same time the book provides a grounding in hydrodynamics, wave theory, and numerical methods...

  5. Recharge estimation for transient ground water modeling.

    Science.gov (United States)

    Jyrkama, Mikko I; Sykes, Jon F; Normani, Stefano D

    2002-01-01

    Reliable ground water models require both an accurate physical representation of the system and appropriate boundary conditions. While physical attributes are generally considered static, boundary conditions, such as ground water recharge rates, can be highly variable in both space and time. A practical methodology incorporating the hydrologic model HELP3 in conjunction with a geographic information system was developed to generate a physically based and highly detailed recharge boundary condition for ground water modeling. The approach uses daily precipitation and temperature records in addition to land use/land cover and soils data. The importance of the method in transient ground water modeling is demonstrated by applying it to a MODFLOW modeling study in New Jersey. In addition to improved model calibration, the results from the study clearly indicate the importance of using a physically based and highly detailed recharge boundary condition in ground water quality modeling, where the detailed knowledge of the evolution of the ground water flowpaths is imperative. The simulated water table is within 0.5 m of the observed values using the method, while the water levels can differ by as much as 2 m using uniform recharge conditions. The results also show that the combination of temperature and precipitation plays an important role in the amount and timing of recharge in cooler climates. A sensitivity analysis further reveals that increasing the leaf area index, the evaporative zone depth, or the curve number in the model will result in decreased recharge rates over time, with the curve number having the greatest impact.

  6. Comparison Of Selected Pedotransfer Functions For The Determination Of Soil Water Retention Curves

    Science.gov (United States)

    Kupec, Michal; Stradiot, Peter; Rehák, Štefan

    2015-09-01

    Soil water retention curves were measured using a sandbox and the pressure plate extractor method on undisturbed soil samples from the Borská Lowland. The basic soil properties (e.g. soil texture, dry bulk density) of the samples were determined. The soil water retention curve was described using the van Genuchten model (Van Genuchten, 1980). The parameters of the model were obtained using the RETC program (Van Genuchten et al., 1991). For the determination of the soil water retention curve parameters, two pedotransfer functions (PTF) were also used that were derived for this area by Skalová (2003) and the Rosetta computer program (Schaap et al., 2001). The performance of the PTFs was characterized using the mean difference and root mean square error.

  7. Comparison Of Selected Pedotransfer Functions For The Determination Of Soil Water Retention Curves

    Directory of Open Access Journals (Sweden)

    Kupec Michal

    2015-09-01

    Full Text Available Soil water retention curves were measured using a sandbox and the pressure plate extractor method on undisturbed soil samples from the Borská Lowland. The basic soil properties (e.g. soil texture, dry bulk density of the samples were determined. The soil water retention curve was described using the van Genuchten model (Van Genuchten, 1980. The parameters of the model were obtained using the RETC program (Van Genuchten et al., 1991. For the determination of the soil water retention curve parameters, two pedotransfer functions (PTF were also used that were derived for this area by Skalová (2003 and the Rosetta computer program (Schaap et al., 2001. The performance of the PTFs was characterized using the mean difference and root mean square error.

  8. Water Transport Models of Moisture Absorption and Sweat Discharge Yarns

    Institute of Scientific and Technical Information of China (English)

    WANG Fa-ming; ZHOU Xiao-hong; WANG Shan-yuan

    2008-01-01

    An important property of moisture absorption and sweat discharge yams is their water transport property. In the paper, two water transport models of moisture absorption and sweat discharge yams were developed to investigate the influence factors on their wicking rate. In parallel Column Pores Model, wicking rate is determined by the equivalent capillary radius R and length of the capillary tube L. In Pellets Accumulation Model, wicking rate is decided by the capillary radius r and length of the fiber unit assemble L0.

  9. Development of Ensemble Model Based Water Demand Forecasting Model

    Science.gov (United States)

    Kwon, Hyun-Han; So, Byung-Jin; Kim, Seong-Hyeon; Kim, Byung-Seop

    2014-05-01

    In recent years, Smart Water Grid (SWG) concept has globally emerged over the last decade and also gained significant recognition in South Korea. Especially, there has been growing interest in water demand forecast and optimal pump operation and this has led to various studies regarding energy saving and improvement of water supply reliability. Existing water demand forecasting models are categorized into two groups in view of modeling and predicting their behavior in time series. One is to consider embedded patterns such as seasonality, periodicity and trends, and the other one is an autoregressive model that is using short memory Markovian processes (Emmanuel et al., 2012). The main disadvantage of the abovementioned model is that there is a limit to predictability of water demands of about sub-daily scale because the system is nonlinear. In this regard, this study aims to develop a nonlinear ensemble model for hourly water demand forecasting which allow us to estimate uncertainties across different model classes. The proposed model is consist of two parts. One is a multi-model scheme that is based on combination of independent prediction model. The other one is a cross validation scheme named Bagging approach introduced by Brieman (1996) to derive weighting factors corresponding to individual models. Individual forecasting models that used in this study are linear regression analysis model, polynomial regression, multivariate adaptive regression splines(MARS), SVM(support vector machine). The concepts are demonstrated through application to observed from water plant at several locations in the South Korea. Keywords: water demand, non-linear model, the ensemble forecasting model, uncertainty. Acknowledgements This subject is supported by Korea Ministry of Environment as "Projects for Developing Eco-Innovation Technologies (GT-11-G-02-001-6)

  10. Incorporation of salinity in Water Availability Modeling

    Science.gov (United States)

    Wurbs, Ralph A.; Lee, Chihun

    2011-10-01

    SummaryNatural salt pollution from geologic formations in the upper watersheds of several large river basins in the Southwestern United States severely constrains the use of otherwise available major water supply sources. The Water Rights Analysis Package modeling system has been routinely applied in Texas since the late 1990s in regional and statewide planning studies and administration of the state's water rights permit system, but without consideration of water quality. The modeling system was recently expanded to incorporate salinity considerations in assessments of river/reservoir system capabilities for supplying water for environmental, municipal, agricultural, and industrial needs. Salinity loads and concentrations are tracked through systems of river reaches and reservoirs to develop concentration frequency statistics that augment flow frequency and water supply reliability metrics at pertinent locations for alternative water management strategies. Flexible generalized capabilities are developed for using limited observed salinity data to model highly variable concentrations imposed upon complex river regulation infrastructure and institutional water allocation/management practices.

  11. Proposed test method for determining discharge rates from water closets

    DEFF Research Database (Denmark)

    Nielsen, V.; Fjord Jensen, T.

    At present the rates at which discharge takes place from sanitary appliances are mostly known only in the form of estimated average values. SBI has developed a measuring method enabling determination of the exact rate of discharge from a sanitary appliance as function of time. The methods depends...... on the application of a calibrated measuring vessel, the volume of water in the vessel being measured at a given moment by means of a transducer and recorded by an UV recorder which is able to follow very rapid variations. In the article the apparatus is described in detail, and an example is given...... of the measurements of the rate of discharge from a WC....

  12. Determinants of single family residential water use across scales in four western US cities.

    Science.gov (United States)

    Chang, Heejun; Bonnette, Matthew Ryan; Stoker, Philip; Crow-Miller, Britt; Wentz, Elizabeth

    2017-10-15

    A growing body of literature examines urban water sustainability with increasing evidence that locally-based physical and social spatial interactions contribute to water use. These studies however are based on single-city analysis and often fail to consider whether these interactions occur more generally. We examine a multi-city comparison using a common set of spatially-explicit water, socioeconomic, and biophysical data. We investigate the relative importance of variables for explaining the variations of single family residential (SFR) water uses at Census Block Group (CBG) and Census Tract (CT) scales in four representative western US cities - Austin, Phoenix, Portland, and Salt Lake City, - which cover a wide range of climate and development density. We used both ordinary least squares regression and spatial error regression models to identify the influence of spatial dependence on water use patterns. Our results show that older downtown areas show lower water use than newer suburban areas in all four cities. Tax assessed value and building age are the main determinants of SFR water use across the four cities regardless of the scale. Impervious surface area becomes an important variable for summer water use in all cities, and it is important in all seasons for arid environments such as Phoenix. CT level analysis shows better model predictability than CBG analysis. In all cities, seasons, and spatial scales, spatial error regression models better explain the variations of SFR water use. Such a spatially-varying relationship of urban water consumption provides additional evidence for the need to integrate urban land use planning and municipal water planning. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Modeling the Water Balloon Slingshot

    Science.gov (United States)

    Bousquet, Benjamin D.; Figura, Charles C.

    2013-01-01

    In the introductory physics courses at Wartburg College, we have been working to create a lab experience focused on the scientific process itself rather than verification of physical laws presented in the classroom or textbook. To this end, we have developed a number of open-ended modeling exercises suitable for a variety of learning environments,…

  14. Determination of tributyltin in whole water matrices under the European Water Framework Directive.

    Science.gov (United States)

    Richter, Janine; Fettig, Ina; Philipp, Rosemarie; Jakubowski, Norbert; Panne, Ulrich; Fisicaro, Paola; Alasonati, Enrica

    2016-08-12

    Monitoring of water quality is important to control water pollution. Contamination of the aquatic system has a large effect on human health and the environment. Under the European Water Framework Directive (WFD) 2000/60/EC and the related directive on environmental quality standards (EQS) in the field of water policy 2008/105/EC, the need for sensitive reference methods was highlighted. Since tributyltin (TBT) is one of the WFD listed priority substances a method was developed which is capable to qualify and quantify the pollutant at the required low WFD EQS of 0.2ngL(-1) in whole water bodies, i.e. in non-filtered water samples with dissolved organic carbon and suspended particulate matter. Therefore special attention was paid on the interaction of TBT with the suspended particulate matter and humic substances to obtain a complete representation of the pollution in surface waters. Different water samples were investigated varying the content of organic dissolved and suspended matter. Quantification was performed using species-specific isotope dilution (SSID) and gas chromatography with inductively coupled plasma mass spectrometry (GC-ICP-MS). Different sample treatment strategies were evaluated and compared. The process of internal standard addition was investigated and optimized, hence the equilibrium between internal standards and matrix is of primary importance to perform accurate SSID. Samples spiked at EQS level were analyzed with a recovery between 95 and 105 %. Additionally real surface water samples were investigated and the TBT concentration for the whole water body was determined and compared with conventional routine analysis method.

  15. Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

    Directory of Open Access Journals (Sweden)

    K. Verbist

    2009-06-01

    Full Text Available In arid and semi-arid zones runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in Northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (Ksat independently. Tension infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between observed soil water content and simulated values was as high as R2=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. Model results indicate that the infiltration trench has a significant effect on

  16. Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

    Directory of Open Access Journals (Sweden)

    K. Verbist

    2009-10-01

    Full Text Available In arid and semi-arid zones, runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study, a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (Ksat independently. The tension infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between the observed soil water content and the simulated values was as high as R2=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. The model results indicate that the infiltration trench has a

  17. Using an inverse modelling approach to evaluate the water retention in a simple water harvesting technique

    Science.gov (United States)

    Verbist, K.; Cornelis, W. M.; Gabriels, D.; Alaerts, K.; Soto, G.

    2009-10-01

    In arid and semi-arid zones, runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Nevertheless, few efforts were observed to quantify the water harvesting processes of these techniques and to evaluate their efficiency. In this study, a combination of detailed field measurements and modelling with the HYDRUS-2D software package was used to visualize the effect of an infiltration trench on the soil water content of a bare slope in northern Chile. Rainfall simulations were combined with high spatial and temporal resolution water content monitoring in order to construct a useful dataset for inverse modelling purposes. Initial estimates of model parameters were provided by detailed infiltration and soil water retention measurements. Four different measurement techniques were used to determine the saturated hydraulic conductivity (Ksat) independently. The tension infiltrometer measurements proved a good estimator of the Ksat value and a proxy for those measured under simulated rainfall, whereas the pressure and constant head well infiltrometer measurements showed larger variability. Six different parameter optimization functions were tested as a combination of soil-water content, water retention and cumulative infiltration data. Infiltration data alone proved insufficient to obtain high model accuracy, due to large scatter on the data set, and water content data were needed to obtain optimized effective parameter sets with small confidence intervals. Correlation between the observed soil water content and the simulated values was as high as R2=0.93 for ten selected observation points used in the model calibration phase, with overall correlation for the 22 observation points equal to 0.85. The model results indicate that the infiltration trench has a significant effect on soil-water storage, especially at the base of the

  18. Water chemistry model development at Total EandP Canada: modeling uncertainty in ore chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kaminsky, H.A.W.; Yoo, A.; Schaffer, M. [Total EandP Canada Ltd. (Canada)

    2011-07-01

    In oil sands mining operations, water chemistry is a key factor as it plays a role in the bitumen recovery and water discharge to the environment. Total Canada have developed a new water chemistry model combining the previous models developed by Rogers and Kasperski and making modifications to improve reliability of the results. Two challenges had to be addressed in the development of this model: making sure that the data used were appropriate, and accurately modeling uncertainty. The aim of this paper is to present the modifications made to the model and other water chemistry models. Laboratory tests were conducted using the double leach and the standard leach methods. Results showed that the standard leach method provides more accurate measurement on batch extraction tests. This paper outlined the challenges of developing a new prediction model; further tests are needed to determine the best method to use in describing ore chemistry.

  19. Separation and determination of dimethylarsenate in natural waters

    Directory of Open Access Journals (Sweden)

    Ben Issa Nureddin

    2012-01-01

    Full Text Available A simple and efficient method for separation and determination of dimethylarsenate DMAs(V was developed in this work. Two resins, a strong base anion exchange (SBAE resin and iron-oxide coated hybrid (HY resin were tested. By simple adjusting pH value of water at 7.00, DMAs(V passed through the HY column without any changes, while all other arsenic species [inorganic arsenic and monomethylarsonate, MMAs(V] were quantitatively bonded on HY resin. The resin capacity was calculated according to the breakthrough points in a fixed bed flow system. At pH 7.00 the HY resins bonded more than 4150 μg g-1 of As(III, 3500 μg g-1 of As(V and 1500 μg g1 of MMAs(V. Arsenic adsorption behavior in the presence of impurities showed tolerance with the respect to potential interference of anions commonly found in natural water. DMAs(V was determined in the effluent by ICP-MS. The detection limit was 0.03 μg L?1 and relative standard deviation (RSD was between 1.1?7.5 %. Proposed method was established performing standard procedures: with external standard, certified reference material and the standard addition method.

  20. Determining Reduced Order Models for Optimal Stochastic Reduced Order Models

    Energy Technology Data Exchange (ETDEWEB)

    Bonney, Matthew S. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Brake, Matthew R.W. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-08-01

    The use of parameterized reduced order models(PROMs) within the stochastic reduced order model (SROM) framework is a logical progression for both methods. In this report, five different parameterized reduced order models are selected and critiqued against the other models along with truth model for the example of the Brake-Reuss beam. The models are: a Taylor series using finite difference, a proper orthogonal decomposition of the the output, a Craig-Bampton representation of the model, a method that uses Hyper-Dual numbers to determine the sensitivities, and a Meta-Model method that uses the Hyper-Dual results and constructs a polynomial curve to better represent the output data. The methods are compared against a parameter sweep and a distribution propagation where the first four statistical moments are used as a comparison. Each method produces very accurate results with the Craig-Bampton reduction having the least accurate results. The models are also compared based on time requirements for the evaluation of each model where the Meta- Model requires the least amount of time for computation by a significant amount. Each of the five models provided accurate results in a reasonable time frame. The determination of which model to use is dependent on the availability of the high-fidelity model and how many evaluations can be performed. Analysis of the output distribution is examined by using a large Monte-Carlo simulation along with a reduced simulation using Latin Hypercube and the stochastic reduced order model sampling technique. Both techniques produced accurate results. The stochastic reduced order modeling technique produced less error when compared to an exhaustive sampling for the majority of methods.

  1. Determinants of tree water use across a floodplain in arid, subtropical northwest Australia

    Science.gov (United States)

    Grierson, Pauline; McLean, Elizabeth; Iles, Jordan; Skrzypek, Grzegorz; Brand, Melinda; O'Donnell, Alison; Siebers, Andre; Dogramaci, Shawan

    2017-04-01

    Riparian zones of ephemeral streams in hot arid regions are subject to unpredictable and generally short-lived flood periods. However, droughts tend to be longer and more severe than floods in their ecological impact as low water availability in surficial alluvium and on the floodplain results in hydrological stress. Resolving how riparian and floodplain vegetation respond to highly variable flow regimes remains a fundamental challenge for estimating water budgets in arid regions, particularly where water tables are subject to groundwater abstraction. Here, we investigated patterns of water use by a range of tree species (Eucalyptus camaldulensis, E. victrix, Acacia citrinoviridis, A. coriacea, Hakea lorea, Atalaya hemiglauca) across a floodplain in the Pilbara region of northwest Australia and assessed vegetation responsiveness to both temporal and spatial variation in water supply. We sought to disentangle the varying contributions of soil water, groundwater and surface water to tree water use to determine the ecological implications of changes in hydrologic connectivity resulting from both seasonal water deficits and anthropogenic management. Diurnal and seasonal dynamics of water use were assessed using sapflux measurements coupled with observations of changing source availability. Source utilization was examined using water stable isotope compositions of xylem, soil, rain, surface water and groundwater. Depending on distance from the stream channel and time since last rainfall, we found that small trees were primarily accessing shallow soil water of meteoric origin while larger eucalypts accessed water deeper in the profile (either stored soil water or groundwater), especially as surface soils dried out. However, tree species were highly variable in their diurnal patterns of water use,including some evidence of nocturnal sapflux in A. coriacea adjacent to streams. Sapflux rates also varied almost four-fold among species but generally declined with increasing

  2. Modelling the budget of middle atmospheric water vapour isotopes

    NARCIS (Netherlands)

    Zahn, A.; Franz, P.; Bechtel, C.; Grooss, J.U.; Röckmann, T.

    2006-01-01

    A one-dimensional chemistry model is applied to study the stable hydrogen (D) and stable oxygen isotope (17O, 18O) composition of water vapour in stratosphere and mesosphere. In the troposphere, this isotope composition is determined by “physical” fractionation effects, that are phase changes (e.g.

  3. Modeling climate change impacts on water trading.

    Science.gov (United States)

    Luo, Bin; Maqsood, Imran; Gong, Yazhen

    2010-04-01

    This paper presents a new method of evaluating the impacts of climate change on the long-term performance of water trading programs, through designing an indicator to measure the mean of periodic water volume that can be released by trading through a water-use system. The indicator is computed with a stochastic optimization model which can reflect the random uncertainty of water availability. The developed method was demonstrated in the Swift Current Creek watershed of Prairie Canada under two future scenarios simulated by a Canadian Regional Climate Model, in which total water availabilities under future scenarios were estimated using a monthly water balance model. Frequency analysis was performed to obtain the best probability distributions for both observed and simulated water quantity data. Results from the case study indicate that the performance of a trading system is highly scenario-dependent in future climate, with trading effectiveness highly optimistic or undesirable under different future scenarios. Trading effectiveness also largely depends on trading costs, with high costs resulting in failure of the trading program.

  4. Modelling Viking ERA Water Ice Clouds

    Science.gov (United States)

    Tamppari, L. K.; Wilson, R. J.; Zurek, R. W.; Paige, D. A.

    1999-09-01

    Water ice clouds in the Martian atmosphere are increasingly becoming recognized as a potentially important aspect of the water cycle and potentially potent mechanism for climte change. In particular, it has been suggested that water ice cloud formation can control the extent of the water column (Kahn, 1990). Further, water ice cloud formation may scavenge dust out of the atmosphere and may prevent cross-equatorial water transport, especially in the northern summer (Clancy, 1996). To address these questions, a combintion of modelling and data analysis can be used. The Viking era water ice clouds were identified (Tamppari et al., 1998) from the IRTM data set. Following that, Tamppari et al. (1999) attempted to identify the cloud opacity and temperature using a 1D, 2-layer ice and dust cloud model. However, data fits were sensitive to the surface temperature, dust opacity and temperature, and ice particle mode radius value, as well as the water ice cloud temperature and opacity. This resulted in an underconstrained problem. A Mars GCM will be employed to provide realistic atmospheric conditions as a function of season, latitude, and longitude. The non-unit surface emissivities (Christensen, 1998) will be added and synthetic IRTM brightness temperatures will be calculated. Results of the comparison of the synthetic and measured brightness temperatures will be presented.

  5. Determination of the principal factors of river water quality through cluster analysis method and its prediction

    Institute of Scientific and Technical Information of China (English)

    Liang GUO; Ying ZHAO; Peng WANG

    2012-01-01

    In this paper, an artificial neural network model was built to predict the Chemical Oxygen Demand (CODMn) measured by permanganate index in Songhua River. To enhance the prediction accuracy, principal factors were determined through the analysis of the weight relation between influencing factors and forecasting object using cluster analysis method, which optimized the topological structure of the prediction model input items of the artificial neural network. It was shown that application of the principal factors in water quality prediction model can improve its forecasting skill significantly through the comparison between results of prediction by artificial neural network and the measurements of the CODMn. This methodology is also applicable to various water quality prediction targets of other water bodies and it is valuable for theoretical study and practical application.

  6. New challenges in integrated water quality modelling

    NARCIS (Netherlands)

    Rode, M.; Arhonditsis, G.; Balin, D.; Kebede, T.; Krysanova, V.; Griensven, A.; Zee, van der S.E.A.T.M.

    2010-01-01

    There is an increasing pressure for development of integrated water quality models that effectively couple catchment and in-stream biogeochemical processes. This need stems from increasing legislative requirements and emerging demands related to contemporary climate and land use changes. Modelling w

  7. Spectrophotometric determination of silica in water. Low range; Determinacion espectrofotometrica de silicio en aguas. Rango bajo

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: eal@nuclear.inin.mx

    1992-07-15

    The spectrophotometric method for the determination of the silica element in water, demineralized water, raw waters, laundry waters, waters treated with ion exchange resins and sea waters is described. This method covers the determination of the silica element in the interval from 20 to 1000 {mu}g/l on 50 ml. of base sample. These limits its can be variable if the size of the used aliquot one is changed for the final determination of the silica element. (Author)

  8. Determining Application Runtimes Using Queueing Network Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Michael L. [Univ. of San Francisco, CA (United States)

    2006-12-14

    Determination of application times-to-solution for large-scale clustered computers continues to be a difficult problem in high-end computing, which will only become more challenging as multi-core consumer machines become more prevalent in the market. Both researchers and consumers of these multi-core systems desire reasonable estimates of how long their programs will take to run (time-to-solution, or TTS), and how many resources will be consumed in the execution. Currently there are few methods of determining these values, and those that do exist are either overly simplistic in their assumptions or require great amounts of effort to parameterize and understand. One previously untried method is queuing network modeling (QNM), which is easy to parameterize and solve, and produces results that typically fall within 10 to 30% of the actual TTS for our test cases. Using characteristics of the computer network (bandwidth, latency) and communication patterns (number of messages, message length, time spent in communication), the QNM model of the NAS-PB CG application was applied to MCR and ALC, supercomputers at LLNL, and the Keck Cluster at USF, with average errors of 2.41%, 3.61%, and -10.73%, respectively, compared to the actual TTS observed. While additional work is necessary to improve the predictive capabilities of QNM, current results show that QNM has a great deal of promise for determining application TTS for multi-processor computer systems.

  9. Performance of chromatographic systems to model soil-water sorption.

    Science.gov (United States)

    Hidalgo-Rodríguez, Marta; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

    2012-08-24

    A systematic approach for evaluating the goodness of chromatographic systems to model the sorption of neutral organic compounds by soil from water is presented in this work. It is based on the examination of the three sources of error that determine the overall variance obtained when soil-water partition coefficients are correlated against chromatographic retention factors: the variance of the soil-water sorption data, the variance of the chromatographic data, and the variance attributed to the dissimilarity between the two systems. These contributions of variance are easily predicted through the characterization of the systems by the solvation parameter model. According to this method, several chromatographic systems besides the reference octanol-water partition system have been selected to test their performance in the emulation of soil-water sorption. The results from the experimental correlations agree with the predicted variances. The high-performance liquid chromatography system based on an immobilized artificial membrane and the micellar electrokinetic chromatography systems of sodium dodecylsulfate and sodium taurocholate provide the most precise correlation models. They have shown to predict well soil-water sorption coefficients of several tested herbicides. Octanol-water partitions and high-performance liquid chromatography measurements using C18 columns are less suited for the estimation of soil-water partition coefficients.

  10. Modelling water uptake efficiency of root systems

    Science.gov (United States)

    Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

    2016-04-01

    Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

  11. The Community Water Model (CWATM) / Development of a community driven global water model

    Science.gov (United States)

    Burek, Peter; Satoh, Yusuke; Greve, Peter; Kahil, Taher; Wada, Yoshihide

    2017-04-01

    With a growing population and economic development, it is expected that water demands will increase significantly in the future, especially in developing regions. At the same time, climate change is expected to alter spatial patterns of hydrological cycle and will have global, regional and local impacts on water availability. Thus, it is important to assess water supply, water demand and environmental needs over time to identify the populations and locations that will be most affected by these changes linked to water scarcity, droughts and floods. The Community Water Model (CWATM) will be designed for this purpose in that it includes an accounting of how future water demands will evolve in response to socioeconomic change and how water availability will change in response to climate. CWATM represents one of the new key elements of IIASA's Water program. It has been developed to work flexibly at both global and regional level at different spatial resolutions. The model is open source and community-driven to promote our work amongst the wider water community worldwide and is flexible enough linking to further planned developments such as water quality and hydro-economic modules. CWATM will be a basis to develop a next-generation global hydro-economic modeling framework that represents the economic trade-offs among different water management options over a basin looking at water supply infrastructure and demand managements. The integrated modeling framework will consider water demand from agriculture, domestic, energy, industry and environment, investment needs to alleviate future water scarcity, and will provide a portfolio of economically optimal solutions for achieving future water management options under the Sustainable Development Goals (SDG) for example. In addition, it will be able to track the energy requirements associated with the water supply system e.g., pumping, desalination and interbasin transfer to realize the linkage with the water-energy economy. In

  12. Wave Numerical Model for Shallow Water

    Institute of Scientific and Technical Information of China (English)

    徐福敏; 严以新; 张长宽; 宋志尧; 茅丽华

    2000-01-01

    The history of forecasting wind waves by wave energy conservation equation is briefly described. Several currently used wave numerical models for shallow water based on different wave theories are discussed. Wave energy conservation models for the simulation of shallow water waves are introduced,with emphasis placed on the SWAN model, which takes use of the most advanced wave research achievements and has been applied to several theoretical and field conditions. The characteristics and applicability of the model, the finite difference numerical scheme of the action balance equation and its source terms computing methods are described in detail. The model has been verified with the propagation refraction numerical experiments for waves propagating in following and opposing currents; finally, the model is applied to the Haian Gulf area to simulate the wave height and wave period field there, and the results are compared with observed data.

  13. Variational modelling of nonlinear water waves

    Science.gov (United States)

    Kalogirou, Anna; Bokhove, Onno

    2015-11-01

    Mathematical modelling of water waves is demonstrated by investigating variational methods. A potential flow water wave model is derived using variational techniques and extented to include explicit time-dependence, leading to non-autonomous dynamics. As a first example, we consider the problem of a soliton splash in a long wave channel with a contraction at its end, resulting after a sluice gate is removed at a finite time. The removal of the sluice gate is included in the variational principle through a time-dependent gravitational potential. A second example involving non-autonomous dynamics concerns the motion of a free surface in a vertical Hele-Shaw cell. Explicit time-dependence now enters the model through a linear damping term due to the effect of wall friction and a term representing the motion of an artificially driven wave pump. In both cases, the model is solved numerically using a Galerkin FEM and the numerical results are compared to wave structures observed in experiments. The water wave model is also adapted to accommodate nonlinear ship dynamics. The novelty is this case is the coupling between the water wave dynamics, the ship dynamics and water line dynamics on the ship. For simplicity, we consider a simple ship structure consisting of V-shaped cross-sections.

  14. Modeling of water radiolysis at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Daemen, L.L.; Kanner, G.S.; Lillard, R.S.; Butt, D.P.; Brun, T.O.; Sommer, W.F.

    1998-12-01

    In spallation neutron sources neutrons are produced when a beam of high-energy particles (e.g., 1 GeV protons) collides with a (water-cooled) heavy metal target such as tungsten. The resulting spallation reactions produce a complex radiation environment (which differs from typical conditions at fission and fusion reactors) leading to the radiolysis of water molecules. Most water radiolysis products are short-lived but extremely reactive. When formed in the vicinity of the target surface they can react with metal atoms, thereby contributing to target corrosion. The authors will describe the results of calculations and experiments performed at Los Alamos to determine the impact on target corrosion of water radiolysis in the spallation radiation environment. The computational methodology relies on the use of the Los Alamos radiation transport code, LAHET, to determine the radiation environment, and the AEA code, FACSIMILE, to model reaction-diffusion processes.

  15. A Water Management Model for Toshka Depression

    Directory of Open Access Journals (Sweden)

    K. M. Fassieh

    2014-01-01

    Full Text Available Toshka Depression (TD, located about 250 km south west of the High Aswan Dam (HAD, consists of four deep-cut basins connected by natural sills. It is required to assess the contribution of TD as a spillway, in enhancing the effectiveness of Lake Nasser in flood control and water availability. However, most related previous works are descriptive and use qualitative methods. In order to provide the required assessment quantitatively, we developed a numerical model which computes TD mass balance and interbasin water movements. The model computes the variation of water volume, surface area, and water level in each one of the four basins (subdepressions, thus depicting their filling sequence, for the past 130 years. This TD response to realistic time series of water inflow gains and evaporation losses is analyzed to compute the TD overflow time series. This response helps assess water availability for agricultural use and effectiveness in alleviating flood risks. Furthermore, the developed model compares between three TD configurations to help the decision maker and recommends (i building a dam—height 10 m—at the end of the fourth subdepression near Kharga Oasis and/or (ii incorporating the third subdepression into TD by digging a canal through the hill that blocks it from the first subdepression.

  16. Manage water resources allocation and water use in the Susquehanna River Basin with a GIS-based model

    Science.gov (United States)

    Zhang, Z.; Balay, J.

    2012-12-01

    Water supply is one of the priority management areas of the Susquehanna River Basin Commission. The desired results of the water supply is to meet immediate and future water needs of the people of the basin, in order to maintain sustainable economic viability, protect instream uses, and ensure ecological diversity. In this study, a GIS-based model is designed and developed to assist water resource planning and management in the Susquehanna River Basin. A comprehensive basin-wide water use geographic database is compiled by integrating reported/approved water use and estimated water use if no monitoring data is available, such as agriculture water use. Then water availability at each WBD10 watersheds within the Susquehanna River Basin are then determined based on the ecosystem flow needs and acceptable hydrologic alternation. A GIS-based basin-wide model integrates the water use and water availability and couples with a module that allows iterative evaluation of water resources management alternatives. The model is capable of quantification and graphic presentation of water use and availability at various spatial scale and performance of spatial analysis and scenario analysis to aid in determining optimized water resources management.

  17. Water quality modelling of Lis River, Portugal.

    Science.gov (United States)

    Vieira, Judite; Fonseca, André; Vilar, Vítor J P; Boaventura, Rui A R; Botelho, Cidália M S

    2013-01-01

    The aim of the study was to predict the impact of flow conditions, discharges and tributaries on the water quality of Lis River using QUAL2Kw model. Calibration of the model was performed, based on data obtained in field surveys carried out in July 2004 and November 2006. Generally the model fitted quite well the experimental data. The results indicated a decrease of water quality in the downstream area of Lis River, after the confluence of Lena, Milagres and Amor tributaries, as a result of discharges of wastewaters containing degradable organics, nutrients and pathogenic organisms from cattle-raising wastewaters, domestic effluents and agricultural runoff. The water quality criteria were exceeded in these areas for dissolved oxygen, biochemical oxygen demand, total nitrogen and faecal coliforms. Water quality modelling in different scenarios showed that the impact of tributaries on the quality of Lis River water was quite negligible and mainly depends on discharges, which are responsible by an increase of almost 45, 13 and 44 % of ultimate carbonaceous biochemical oxygen demand (CBOD(u)), ammonium nitrogen and faecal coliforms, for winter simulation, and 23, 33 and 36 % for summer simulation, respectively, when compared to the real case scenario.

  18. Determination of metals in water from Billings dam, Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Talita; Sarkis, Jorge E.S.; Ulrich, Joao C.; Yamaguishi, Renata Bazante, E-mail: taoliveira@ipen.br, E-mail: jesarkis@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Menezes, Luciana Carvalho Bezerra de; Castro, Paula Maria Genova de; Monteiro Junior, Adalberto Jose; Maruyama, Lidia Sumile, E-mail: lcbm@usp.br [Instituto de Pesca, (IP/SAA-SP), Sao Paulo, SP (Brazil). Secretaria da Agricultura e Abastecimento do Estado de Sao Paulo

    2013-07-01

    The Billings reservoir, located in Sao Paulo, Brazil, is used for several purposes such as: water supply, electric generation, fishing and leisure. Although considered an area of environmental protection, in recent years the dam has suffered diverse environmental aggressions including the release of toxic metals. This study presents a recent evaluation of metal contents along the Dam. Samples were collected every three months during the period of winter 2009 to summer 2010. Samples were collected in thirteen points along of the dam, as follows: Rio dos Porcos (Point 1), Summit Control (Point 2), Ilha do Bigua (Point 3), Casa Caida (Point 4), Barragem (Point 5), Foz de Taquacetuba (Point 6), Braco Borore (Point 7), Foz de Borore (Point 8), Alvarenga (Point 9), Pedreira (Point 10), Borore's Margin (Point 11), Capivari I's Margin (Point 12) and Capivari II's Margin (Point 13). The determination of Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn was performed by using high resolution inductively coupled plasma mass spectrometer (HR-ICPMS). The methodology has been validated using certified reference material Riverine Water Reference Material for Trace Metals provided by National Research Council Canada (NRCC). The sampling points located in the Pedreira, Borore's Margin, Alvarenga, Barragem Taquacetuba, Casa Caida e Ilha do Bigua presented the highest concentrations. The level for Fe, Cu and Ni were higher than the ones reported in the literature and above the limit set by CONAMA 2914/201. (author)

  19. Voltammetric Determination of Ni and Co in Water Samples

    Science.gov (United States)

    Herrera-Melian, Jose Alberto; Dona-Rodriguez, Jose Miguel; Hernandez-Brito, Joaquin; Perez Pena, Jesus

    1997-12-01

    Stripping voltammetry has attracted considerable attention for the determination of trace and ultratrace metals. This is mainly due to its high sensitivity and low cost of instrumentation. In adsorptive stripping voltammetry an organometallic complex is formed by the addition of a suitable ligand to the sample. The complex is adsorbed onto the Hg-drop by the application of the proper adsorption potential (more positive than E1/2) and solution stirring. After an adsorption period a cathodic (negative going) potential scan is applied and the metal concentration is calculated by the standard addition method. Nickel is found in natural waters at nM levels and is closely related with phosphates and silicates. Cobalt is a component of vitamin B12 and occurs in natural waters at concentration about 0.1 nM. We propose the voltammetric analysis of these elements by adsorptive stripping voltammetry as an introductory laboratory experiment for advanced chemistry or for chemical or environmental engineering students. The experiment has been proven to be very suitable for the laboratory part of the instrumental analysis course at the University of Las Palmas de Gran Canaria (Spain). In general, about 70% of the students have obtained good agreement (less than 10% of difference) between their results and the expected ones. Two hours is enough for the overall instrumental performance and the preparation of Ni and Co standards.

  20. Data-driven behavioural modelling of residential water consumption to inform water demand management strategies

    Science.gov (United States)

    Giuliani, Matteo; Cominola, Andrea; Alshaf, Ahmad; Castelletti, Andrea; Anda, Martin

    2016-04-01

    The continuous expansion of urban areas worldwide is expected to highly increase residential water demand over the next few years, ultimately challenging the distribution and supply of drinking water. Several studies have recently demonstrated that actions focused only on the water supply side of the problem (e.g., augmenting existing water supply infrastructure) will likely fail to meet future demands, thus calling for the concurrent deployment of effective water demand management strategies (WDMS) to pursue water savings and conservation. However, to be effective WDMS do require a substantial understanding of water consumers' behaviors and consumption patterns at different spatial and temporal resolutions. Retrieving information on users' behaviors, as well as their explanatory and/or causal factors, is key to spot potential areas for targeting water saving efforts and to design user-tailored WDMS, such as education campaigns and personalized recommendations. In this work, we contribute a data-driven approach to identify household water users' consumption behavioural profiles and model their water use habits. State-of-the-art clustering methods are coupled with big data machine learning techniques with the aim of extracting dominant behaviors from a set of water consumption data collected at the household scale. This allows identifying heterogeneous groups of consumers from the studied sample and characterizing them with respect to several consumption features. Our approach is validated onto a real-world household water consumption dataset associated with a variety of demographic and psychographic user data and household attributes, collected in nine towns of the Pilbara and Kimberley Regions of Western Australia. Results show the effectiveness of the proposed method in capturing the influence of candidate determinants on residential water consumption profiles and in attaining sufficiently accurate predictions of users' consumption behaviors, ultimately providing

  1. [Water environmental capacity calculation model for the rivers in drinking water source conservation area].

    Science.gov (United States)

    Chen, Ding-jiang; Lü, Jun; Shen, Ye-na; Jin, Shu-quan; Shi, Yi-ming

    2008-09-01

    Based on the one-dimension model for water environmental capacity (WEC) in river, a new model for the WEC estimation in river-reservoir system was developed in drinking water source conservation area (DWSCA). In the new model, the concept was introduced that the water quality target of the rivers in DWSCA was determined by the water quality demand of reservoir for drinking water source. It implied that the WEC of the reservoir could be used as the water quality control target at the reach-end of the upstream rivers in DWSCA so that the problems for WEC estimation might be avoided that the differences of the standards for a water quality control target between in river and in reservoir, such as the criterions differences for total phosphorus (TP)/total nitrogen (TN) between in reservoir and in river according to the National Surface Water Quality Standard of China (GB 3838-2002), and the difference of designed hydrology conditions for WEC estimation between in reservoir and in river. The new model described the quantitative relationship between the WEC of drinking water source and of the river, and it factually expressed the continuity and interplay of these low water areas. As a case study, WEC for the rivers in DWSCA of Laohutan reservoir located in southeast China was estimated using the new model. Results indicated that the WEC for TN and TP was 65.05 t x a(-1) and 5.05 t x a(-1) in the rivers of the DWSCA, respectively. According to the WEC of Laohutan reservoir and current TN and TP quantity that entered into the rivers, about 33.86 t x a(-1) of current TN quantity should be reduced in the DWSCA, while there was 2.23 t x a(-1) of residual WEC of TP in the rivers. The modeling method was also widely applicable for the continuous water bodies with different water quality targets, especially for the situation of higher water quality control target in downstream water body than that in upstream.

  2. Water-vortex-stabilized electric arc: III. Radial energy transport, determination of water-vapour-boundary and arc performance

    Energy Technology Data Exchange (ETDEWEB)

    Jenista, Jiri [Institute of Plasma Physics ASCR, Za Slovankou 3, PO Box 17, Prague 8, 182 21 (Czech Republic)

    2003-12-07

    This paper is concerned with numerical modelling of an electric arc stabilized by a water vortex. The two-dimensional axisymmetric model presented includes the arc discharge area between the cathode and the outlet nozzle of the water plasma torch. The aims of the numerical simulations are: (1) to assess the influence of radial position of the water-vapour-boundary in the discharge chamber on arc performance and overall radial energy transport within the arc; (2) to determine the most probable mass flow rates and radii of the water-vapour-boundary in the discharge chamber for a prescribed current; (3) to demonstrate arc performance for two radiation models involved; and (4) to estimate validity of local thermodynamic equilibrium (LTE) conditions within the arc column. The rate of evaporation of water is calculated from the conduction and radiation heat fluxes at the water vapour surface for the specified mass flow rate. The behaviour of such an arc has been studied for a range of current 300-600 A. It is shown that changes of bulk magnitudes of different terms in the momentum and energy equations within the arc column as a function of arc radius enable us to reveal transitions of temperature and velocity fields from one steady state to a qualitatively different one. The best fit between experiment and numerical simulation for all currents exists for the mean arc radius {approx} 3.3 mm. Deviations from LTE within the arc column are estimated with the criteria for kinetic equilibrium and spatial temperature gradients.

  3. Mathematical modelling of plant water and nutrient uptake

    Science.gov (United States)

    Roose, Tiina

    2010-05-01

    In this presentation I will describe a model of plant water and nutrient uptake and how to translate this model and experimental data from the single root scale to the root branching structure scale. The model starts at the single root scale and describes the water and nutrient movement in the soil using Richards' equation (water uptake) and diffusion-convection equation (nutrient uptake). The water and nutrient uptake in the single root scale model is represented by boundary conditions. In the case of nutrient uptake this has the form of a non-linear Michaelis-Menten uptake law and in the case of water this is given by a soil-xylem pressure difference boundary condition. The flow of water in the xylem is modeled as Poiseuille flow. We solve the single root scale models using the analytic approximate technique of asymptotic expansions similar to Oseen expansions known from fluid dynamics. We will then discuss how to use the analytic expression to estimate the water and nutrient uptake by growing root branching systems. We model the growth of the root system using a dynamic population model to describe the branching and elongation of roots in the branching system. This root branching population model results in a hyperbolic equation similar to age dependent population models and it can be solved fully analytically using the method of characteristics. Thus we have a fully analytic description of the root branching system evolution. We use this branching model to estimate the nutrient uptake in a scenario when the competition between subbranches is small, i.e., as it is in the case of phosphate, potassium and arsenic. We compare our approximate analytic model to a full 3d simulation of the root system phosphate uptake and find that the analytic model almost perfectly reproduces the 3d numerical model. In addition the analytic model can be included in larger field/catchment/climate scale models something which is not practically possible with the numerical simulations

  4. Modelling of water potential and water uptake rate of tomato plants in the greenhouse: preliminary results.

    NARCIS (Netherlands)

    Bruggink, G.T.; Schouwink, H.E.; Gieling, Th.H.

    1988-01-01

    A dynamic model is presented which predicts water potential and water uptake rate of greenhouse tomato plants using transpiration rate as input. The model assumes that water uptake is the resultant of water potential and hydraulic resistance, and that water potential is linearly related to water con

  5. FIRESTORM: Modelling the water quality risk of wildfire.

    Science.gov (United States)

    Mason, C. I.; Sheridan, G. J.; Smith, H. G.; Jones, O.; Chong, D.; Tolhurst, K.

    2012-04-01

    Following wildfire, loss of vegetation and changes to soil properties may result in decreases in infiltration rates, less rainfall interception, and higher overland flow velocities. Rainfall events affecting burn areas before vegetation recovers can cause high magnitude erosion events that impact on downstream water quality. For cities and towns that rely upon fire-prone forest catchments for water supply, wildfire impacts on water quality represent a credible risk to water supply security. Quantifying the risk associated with the occurrence of wildfires and the magnitude of water quality impacts has important implications for managing water supplies. At present, no suitable integrative model exists that considers the probabilistic nature of system inputs as well as the range of processes and scales involved in this problem. We present FIRESTORM, a new model currently in development that aims to determine the range of sediment and associated contaminant loads that may be delivered to water supply reservoirs from the combination of wildfire and subsequent rainfall events. This Monte Carlo model incorporates the probabilistic nature of fire ignition, fire weather and rainfall, and includes deterministic models for fire behaviour and locally dominant erosion processes. FIRESTORM calculates the magnitude and associated annual risk of catchment-scale sediment loads associated with the occurrence of wildfire and rainfall generated by two rain event types. The two event types are localised, high intensity, short-duration convective storms, and widespread, longer duration synoptic-scale rainfall events. Initial application and testing of the model will focus on the two main reservoirs supplying water to Melbourne, Australia, both of which are situated in forest catchments vulnerable to wildfire. Probabilistic fire ignition and weather scenarios have been combined using 40 years of fire records and weather observations. These are used to select from a dataset of over 80

  6. determinants of residential per capita water demand of makurdi ...

    African Journals Online (AJOL)

    user

    explains 43% of the variation in residential per capital water demand of Makurdi. The F test (F= 14.236 ... safe drinking water. Today, a large .... and so resort to the use of sachet water for drinking ..... Water Supply Facilities Maintenance held at.

  7. Uncertainty in surface water flood risk modelling

    Science.gov (United States)

    Butler, J. B.; Martin, D. N.; Roberts, E.; Domuah, R.

    2009-04-01

    Two thirds of the flooding that occurred in the UK during summer 2007 was as a result of surface water (otherwise known as ‘pluvial') rather than river or coastal flooding. In response, the Environment Agency and Interim Pitt Reviews have highlighted the need for surface water risk mapping and warning tools to identify, and prepare for, flooding induced by heavy rainfall events. This need is compounded by the likely increase in rainfall intensities due to climate change. The Association of British Insurers has called for the Environment Agency to commission nationwide flood risk maps showing the relative risk of flooding from all sources. At the wider European scale, the recently-published EC Directive on the assessment and management of flood risks will require Member States to evaluate, map and model flood risk from a variety of sources. As such, there is now a clear and immediate requirement for the development of techniques for assessing and managing surface water flood risk across large areas. This paper describes an approach for integrating rainfall, drainage network and high-resolution topographic data using Flowroute™, a high-resolution flood mapping and modelling platform, to produce deterministic surface water flood risk maps. Information is provided from UK case studies to enable assessment and validation of modelled results using historical flood information and insurance claims data. Flowroute was co-developed with flood scientists at Cambridge University specifically to simulate river dynamics and floodplain inundation in complex, congested urban areas in a highly computationally efficient manner. It utilises high-resolution topographic information to route flows around individual buildings so as to enable the prediction of flood depths, extents, durations and velocities. As such, the model forms an ideal platform for the development of surface water flood risk modelling and mapping capabilities. The 2-dimensional component of Flowroute employs

  8. Interactive Water Resources Modeling and Model Use: An Overview

    Science.gov (United States)

    Loucks, Daniel P.; Kindler, Janusz; Fedra, Kurt

    1985-02-01

    This serves as an introduction for the following sequence of five papers on interactive water resources and environmental management, policy modeling, and model use. We review some important shortcomings of many management and policy models and argue for improved human-computer-model interaction and communication. This interaction can lead to more effective model use which in turn should facilitate the exploration, analysis, and synthesis of alternative designs, plans, and policies by those directly involved in the planning, management, or policy making process. Potential advantages of interactive modeling and model use, as well as some problems and research needs, are discussed.

  9. A generic hydroeconomic model to assess future water scarcity

    Science.gov (United States)

    Neverre, Noémie; Dumas, Patrice

    2015-04-01

    We developed a generic hydroeconomic model able to confront future water supply and demand on a large scale, taking into account man-made reservoirs. The assessment is done at the scale of river basins, using only globally available data; the methodology can thus be generalized. On the supply side, we evaluate the impacts of climate change on water resources. The available quantity of water at each site is computed using the following information: runoff is taken from the outputs of CNRM climate model (Dubois et al., 2010), reservoirs are located using Aquastat, and the sub-basin flow-accumulation area of each reservoir is determined based on a Digital Elevation Model (HYDRO1k). On the demand side, agricultural and domestic demands are projected in terms of both quantity and economic value. For the agricultural sector, globally available data on irrigated areas and crops are combined in order to determine irrigated crops localization. Then, crops irrigation requirements are computed for the different stages of the growing season using Allen (1998) method with Hargreaves potential evapotranspiration. Irrigation water economic value is based on a yield comparison approach between rainfed and irrigated crops. Potential irrigated and rainfed yields are taken from LPJmL (Blondeau et al., 2007), or from FAOSTAT by making simple assumptions on yield ratios. For the domestic sector, we project the combined effects of demographic growth, economic development and water cost evolution on future demands. The method consists in building three-blocks inverse demand functions where volume limits of the blocks evolve with the level of GDP per capita. The value of water along the demand curve is determined from price-elasticity, price and demand data from the literature, using the point-expansion method, and from water costs data. Then projected demands are confronted to future water availability. Operating rules of the reservoirs and water allocation between demands are based on

  10. Modelling raster-based monthly water balance components for Europe

    Energy Technology Data Exchange (ETDEWEB)

    Ulmen, C.

    2000-11-01

    The terrestrial runoff component is a comparatively small but sensitive and thus significant quantity in the global energy and water cycle at the interface between landmass and atmosphere. As opposed to soil moisture and evapotranspiration which critically determine water vapour fluxes and thus water and energy transport, it can be measured as an integrated quantity over a large area, i.e. the river basin. This peculiarity makes terrestrial runoff ideally suited for the calibration, verification and validation of general circulation models (GCMs). Gauging stations are not homogeneously distributed in space. Moreover, time series are not necessarily continuously measured nor do they in general have overlapping time periods. To overcome this problems with regard to regular grid spacing used in GCMs, different methods can be applied to transform irregular data to regular so called gridded runoff fields. The present work aims to directly compute the gridded components of the monthly water balance (including gridded runoff fields) for Europe by application of the well-established raster-based macro-scale water balance model WABIMON used at the Federal Institute of Hydrology, Germany. Model calibration and validation is performed by separated examination of 29 representative European catchments. Results indicate a general applicability of the model delivering reliable overall patterns and integrated quantities on a monthly basis. For time steps less then too weeks further research and structural improvements of the model are suggested. (orig.)

  11. Modeling the response of peach fruit growth to water stress.

    Science.gov (United States)

    Génard, M; Huguet, J G

    1996-04-01

    We applied a semi-mechanistic model of fresh matter accumulation to peach fruit during the stage of rapid mesocarp development. The model, which is based on simple hypotheses of fluid flows into and out of the fruit, assumes that solution flow into the fruit increases with fruit weight and transpiration per unit weight, and decreases with the maximum daily shrinkage of the trunk, which was used as an indicator of water stress. Fruit transpiration was assumed to increase with fruit size and with radiation. Fruit respiration was considered to be related to fruit growth and to temperature. The model simulates variability in growth among fruits according to climatic conditions, degree of water stress and weight of the fruit at the beginning of the simulation. We used data obtained from well-watered and water-stressed trees grown in containers to estimate model parameters and to test the model. There was close agreement between the simulated and measured values. A sensitivity analysis showed that initial fruit weight partly determined the variation in growth among fruits. The analysis also indicated that there was an optimal irradiance for fruit growth and that the effect of high global radiation on growth varied according to the stage of fruit development. Water stress, which was the most important factor influencing fruit growth, rapidly depressed growth, particularly when applied late in the season.

  12. Water-Air Volatilization Factors to Determine Volatile Organic Compound (VOC Reference Levels in Water

    Directory of Open Access Journals (Sweden)

    Vicenç Martí

    2014-06-01

    Full Text Available The goal of this work is the modeling and calculation of volatilization factors (VFs from water to air for volatile organic compounds (VOCs in order to perform human health risk-based reference levels (RLs for the safe use of water. The VF models have been developed starting from the overall mass-transfer coefficients (Koverall concept from air to water for two interaction geometries (flat surface and spherical droplets in indoor and outdoor scenarios. For a case study with five groups of risk scenarios and thirty VOCs, theoretical VFs have been calculated by using the developed models. Results showed that Koverall values for flat and spherical surface geometries were close to the mass transfer coefficient for water (KL when Henry’s law constant (KH was high. In the case of spherical drop geometry, the fraction of volatilization (fV was asymptotical when increasing KH with fV values also limited due to Koverall. VFs for flat surfaces were calculated from the emission flux of VOCs, and results showed values close to 1000KH for the most conservative indoor scenarios and almost constant values for outdoor scenarios. VFs for spherical geometry in indoor scenarios followed also constant VFs and were far from 1000KH. The highest calculated VF values corresponded to the E2A, E2B, E3A and E5A scenarios and were compared with experimental and real results in order to check the goodness of flat and sphere geometry models. Results showed an overestimation of calculated values for the E2A and E2B scenarios and an underestimation for the E3A and E5A scenarios. In both cases, most of the calculated VFs were from 0.1- to 10-times higher than experimental/real values.

  13. Model independent spin determination at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Edelhaeuser, Lisa

    2012-04-25

    By the end of the year 2011, both the CMS and ATLAS experiments at the Large Hadron Collider have recorded around 5 inverse femtobarns of data at an energy of 7 TeV. There are only vague hints from the already analysed data towards new physics at the TeV scale. However, one knows that around this scale, new physics should show up so that theoretical issues of the standard model of particle physics can be cured. During the last decades, extensions to the standard model that are supposed to solve its problems have been constructed, and the corresponding phenomenology has been worked out. As soon as new physics is discovered, one has to deal with the problem of determining the nature of the underlying model. A first hint is of course given by the mass spectrum and quantum numbers such as electric and colour charges of the new particles. However, there are two popular model classes, supersymmetric models and extradimensional models, which can exhibit almost equal properties at the accessible energy range. Both introduce partners to the standard model particles with the same charges and thus one needs an extended discrimination method. From the origin of these partners arises a relevant difference: The partners constructed in extradimensional models have the same spin as their standard model partners while in Supersymmetry they differ by spin 1/2. These different spins have an impact on the phenomenology of the two models. For example, one can exploit the fact that the total cross sections are affected, but this requires a very good knowledge of the couplings and masses involved. Another approach uses angular distributions depending on the particle spins. A prevailing method based on this idea uses the invariant mass distribution of the visible particles in decay chains. One can relate these distributions to the spin of the particle mediating the decay since it reflects itself in the highest power of the invariant mass s{sub ff} of the adjacent particles. In this thesis

  14. Model independent spin determination at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Edelhaeuser, Lisa

    2012-04-25

    By the end of the year 2011, both the CMS and ATLAS experiments at the Large Hadron Collider have recorded around 5 inverse femtobarns of data at an energy of 7 TeV. There are only vague hints from the already analysed data towards new physics at the TeV scale. However, one knows that around this scale, new physics should show up so that theoretical issues of the standard model of particle physics can be cured. During the last decades, extensions to the standard model that are supposed to solve its problems have been constructed, and the corresponding phenomenology has been worked out. As soon as new physics is discovered, one has to deal with the problem of determining the nature of the underlying model. A first hint is of course given by the mass spectrum and quantum numbers such as electric and colour charges of the new particles. However, there are two popular model classes, supersymmetric models and extradimensional models, which can exhibit almost equal properties at the accessible energy range. Both introduce partners to the standard model particles with the same charges and thus one needs an extended discrimination method. From the origin of these partners arises a relevant difference: The partners constructed in extradimensional models have the same spin as their standard model partners while in Supersymmetry they differ by spin 1/2. These different spins have an impact on the phenomenology of the two models. For example, one can exploit the fact that the total cross sections are affected, but this requires a very good knowledge of the couplings and masses involved. Another approach uses angular distributions depending on the particle spins. A prevailing method based on this idea uses the invariant mass distribution of the visible particles in decay chains. One can relate these distributions to the spin of the particle mediating the decay since it reflects itself in the highest power of the invariant mass s{sub ff} of the adjacent particles. In this thesis

  15. Building the Method to Determine the Rate of Freezing Water in Penaeus monodon of the Freezing Process

    Directory of Open Access Journals (Sweden)

    Nguyen Tan Dzung

    2012-10-01

    Full Text Available The method of determination the rate of freezing water in Penaeus monodon of freezing process was established on base the equation of energy balance in warming up process Penaeus monodon after freezing to determine specific heat of Penaeus monodon. The result obtained was built the mathematical model (19 to determine the rate of freezing water according to the freezing temperature of Penaeus monodon. The results indicated that when water was completely frozen (ω = 1 or 100%, the optimal freezing temperature of Penaeus monodon was-22.00°C.

  16. On inclusion of water resource management in Earth system models - Part 1: Problem definition and representation of water demand

    Science.gov (United States)

    Nazemi, A.; Wheater, H. S.

    2015-01-01

    Human activities have caused various changes to the Earth system, and hence the interconnections between human activities and the Earth system should be recognized and reflected in models that simulate Earth system processes. One key anthropogenic activity is water resource management, which determines the dynamics of human-water interactions in time and space and controls human livelihoods and economy, including energy and food production. There are immediate needs to include water resource management in Earth system models. First, the extent of human water requirements is increasing rapidly at the global scale and it is crucial to analyze the possible imbalance between water demands and supply under various scenarios of climate change and across various temporal and spatial scales. Second, recent observations show that human-water interactions, manifested through water resource management, can substantially alter the terrestrial water cycle, affect land-atmospheric feedbacks and may further interact with climate and contribute to sea-level change. Due to the importance of water resource management in determining the future of the global water and climate cycles, the World Climate Research Program's Global Energy and Water Exchanges project (WRCP-GEWEX) has recently identified gaps in describing human-water interactions as one of the grand challenges in Earth system modeling (GEWEX, 2012). Here, we divide water resource management into two interdependent elements, related firstly to water demand and secondly to water supply and allocation. In this paper, we survey the current literature on how various components of water demand have been included in large-scale models, in particular land surface and global hydrological models. Issues of water supply and allocation are addressed in a companion paper. The available algorithms to represent the dominant demands are classified based on the demand type, mode of simulation and underlying modeling assumptions. We discuss

  17. Polarizable water model for Dissipative Particle Dynamics

    Science.gov (United States)

    Pivkin, Igor; Peter, Emanuel

    2015-11-01

    Dissipative Particle Dynamics (DPD) is an efficient particle-based method for modeling mesoscopic behavior of fluid systems. DPD forces conserve the momentum resulting in a correct description of hydrodynamic interactions. Polarizability has been introduced into some coarse-grained particle-based simulation methods; however it has not been done with DPD before. We developed a new polarizable coarse-grained water model for DPD, which employs long-range electrostatics and Drude oscillators. In this talk, we will present the model and its applications in simulations of membrane systems, where polarization effects play an essential role.

  18. Modeling of Water Movement Near Saturation

    Science.gov (United States)

    Ippisch, O.; Graf, H.; Bastian, P.; Roth, K.

    Water transport in unsaturated porous media is often described using Richards' equa- tion. However Richards' equation is based on the assumption that the gas phase is mobile enough to be always (nearly) at atmospheric pressure. This assumption is not valid if the porous medium is nearly saturated with water. The difference between model calculations using Richards' equation and a multiphase formulation is analyzed and compared to results from multistep outflow experiments with columns of sintered glass. The chosen parameterization for the hydraulic param- eters (van Genuchten/Brooks-Corey) proves to expecially important.

  19. DEVELOPMENT OF RAPID TECHNIQUE FOR DETERMINATION OF THE TOTAL MINERALIZATION OF NATURAL WATERS

    Directory of Open Access Journals (Sweden)

    T. A. Kuchmenko

    2015-01-01

    Full Text Available A new approach has been proposed for rapid and easy evaluation of a indicator of quality and properties of natural water - soluble salt content (mineralization. The method of quartz crystal microbalance is employed at load of the mass-sensitive resonator electrode (BAW-type with investigated water. The degree of correlation between the various indicators related to the contents of salts and insoluble compounds and the level of mineralization obtained by the standard method (gravimetry has been studied. A procedure for salt weighing by single sensor at unilateral load with small sample of natural water has been developed. The optimal conditions for measurement is established using the design of experiment by model 23 . The possibilities of quartz crystal microbalance for determination of non-volatile compounds in the water are described. The calibration of piezosensor is produced by standard solution NaCl (c = 1.000 g / dm3 at optimal conditions of experiment. The adequacy and accuracy of proposed technique is assessed by the correlation between the results of quartz crystal microbalance and conductometry. The correlation between indicators of mineralization established by quartz crystal microbalance and gravimetry is found. It has been obtained an equation that can be used to calculate the standard indicator of the mineralization by the results of a quartz crystal microbalance using single sensor. The approaches to enhance the analytical capabilities of the developed technique for water with low and high mineralization are proposed. The metrological characteristics of quartz crystal microbalance of insoluble compounds in natural water are estimated. A new technique of determination of the mass concentration of the dry residue in water with a conductivity of 0.2 mS or above has been developed, which can be used for rapid analysis of the water at nonlaboratory conditions and in the laboratory for rapid obtaining the information about a sample.

  20. Determination of trihalomethanes in water samples: A review

    Energy Technology Data Exchange (ETDEWEB)

    Perez Pavon, Jose Luis [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Universidad de Salamanca, 37008 Salamanca (Spain)], E-mail: jlpp@usal.es; Herrero Martin, Sara; Garcia Pinto, Carmelo; Moreno Cordero, Bernardo [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias Quimicas, Universidad de Salamanca, 37008 Salamanca (Spain)

    2008-11-23

    This article reviews the most recent literature addressing the analytical methods applied for trihalomethanes (THMs) determination in water samples. This analysis is usually performed with gas chromatography (GC) combined with a preconcentration step. The detectors most widely used in this type of analyses are mass spectrometers (MS) and electron capture detectors (ECD). Here, we review the analytical characteristics, the time required for analysis, and the simplicity of the optimised methods. The main difference between these methods lies in the sample pretreatment step; therefore, special emphasis is placed on this aspect. The techniques covered are direct aqueous injection (DAI), liquid-liquid extraction (LLE), headspace (HS), and membrane-based techniques. We also review the main chromatographic columns employed and consider novel aspects of chromatographic analysis, such as the use of fast gas chromatography (FGC). Concerning the detection step, besides the common techniques, the use of uncommon detectors such as fluorescence detector, pulsed discharge photoionization detector (PDPID), dry electrolytic conductivity detector (DELCD), atomic emission detector (AED) and inductively coupled plasma-mass spectrometry (ICP-MS) for this type of analysis is described.

  1. A Provenance Model for Real-Time Water Information Systems

    Science.gov (United States)

    Liu, Q.; Bai, Q.; Zednik, S.; Taylor, P.; Fox, P. A.; Taylor, K.; Kloppers, C.; Peters, C.; Terhorst, A.; West, P.; Compton, M.; Shu, Y.; Provenance Management Team

    2010-12-01

    Generating hydrological data products, such as flow forecasts, involves complex interactions among instruments, data simulation models, computational facilities and data providers. Correct interpretation of the data produced at various stages requires good understanding of how data was generated or processed. Provenance describes the lineage of a data product. Making provenance information accessible to hydrologists and decision makers not only helps to determine the data’s value, accuracy and authorship, but also enables users to determine the trustworthiness of the data product. In the water domain, WaterML2 [1] is an emerging standard which describes an information model and format for the publication of water observations data in XML. The W3C semantic sensor network incubator group (SSN-XG) [3] is producing ontologies for the description of sensor configurations. By integrating domain knowledge of this kind into the provenance information model, the integrated information model will enable water domain researchers and water resource managers to better analyse how observations and derived data products were generated. We first introduce the Proof Mark Language (PML2) [2], WaterML2 and the SSN-XG sensor ontology as the proposed provenance representation formalism. Then we describe some initial implementations how these standards could be integrated to represent the lineage of water information products. Finally we will highlight how the provenance model for a distributed real-time water information system assists the interpretation of the data product and establishing trust. Reference [1] Taylor, P., Walker, G., Valentine, D., Cox, Simon: WaterML2.0: Harmonising standards for water observation data. Geophysical Research Abstracts. Vol. 12. [2] da Silva, P.P., McGuinness, D.L., Fikes, R.: A proof markup language for semantic web services. Inf. Syst. 31(4) (2006), 381-395. [3] W3C Semantic Sensor Network Incubator Group http://www.w3.org/2005/Incubator

  2. Ares I Scale Model Acoustic Test Above Deck Water Sound Suppression Results

    Science.gov (United States)

    Counter, Douglas D.; Houston, Janice D.

    2011-01-01

    The Ares I Scale Model Acoustic Test (ASMAT) program test matrix was designed to determine the acoustic reduction for the Liftoff acoustics (LOA) environment with an above deck water sound suppression system. The scale model test can be used to quantify the effectiveness of the water suppression system as well as optimize the systems necessary for the LOA noise reduction. Several water flow rates were tested to determine which rate provides the greatest acoustic reductions. Preliminary results are presented.

  3. River water temperature and fish growth forecasting models

    Science.gov (United States)

    Danner, E.; Pike, A.; Lindley, S.; Mendelssohn, R.; Dewitt, L.; Melton, F. S.; Nemani, R. R.; Hashimoto, H.

    2010-12-01

    Water is a valuable, limited, and highly regulated resource throughout the United States. When making decisions about water allocations, state and federal water project managers must consider the short-term and long-term needs of agriculture, urban users, hydroelectric production, flood control, and the ecosystems downstream. In the Central Valley of California, river water temperature is a critical indicator of habitat quality for endangered salmonid species and affects re-licensing of major water projects and dam operations worth billions of dollars. There is consequently strong interest in modeling water temperature dynamics and the subsequent impacts on fish growth in such regulated rivers. However, the accuracy of current stream temperature models is limited by the lack of spatially detailed meteorological forecasts. To address these issues, we developed a high-resolution deterministic 1-dimensional stream temperature model (sub-hourly time step, sub-kilometer spatial resolution) in a state-space framework, and applied this model to Upper Sacramento River. We then adapted salmon bioenergetics models to incorporate the temperature data at sub-hourly time steps to provide more realistic estimates of salmon growth. The temperature model uses physically-based heat budgets to calculate the rate of heat transfer to/from the river. We use variables provided by the TOPS-WRF (Terrestrial Observation and Prediction System - Weather Research and Forecasting) model—a high-resolution assimilation of satellite-derived meteorological observations and numerical weather simulations—as inputs. The TOPS-WRF framework allows us to improve the spatial and temporal resolution of stream temperature predictions. The salmon growth models are adapted from the Wisconsin bioenergetics model. We have made the output from both models available on an interactive website so that water and fisheries managers can determine the past, current and three day forecasted water temperatures at

  4. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    Science.gov (United States)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  5. Behavioural modelling of irrigation decision making under water scarcity

    Science.gov (United States)

    Foster, T.; Brozovic, N.; Butler, A. P.

    2013-12-01

    Providing effective policy solutions to aquifer depletion caused by abstraction for irrigation is a key challenge for socio-hydrology. However, most crop production functions used in hydrological models do not capture the intraseasonal nature of irrigation planning, or the importance of well yield in land and water use decisions. Here we develop a method for determining stochastic intraseasonal water use that is based on observed farmer behaviour but is also theoretically consistent with dynamically optimal decision making. We use the model to (i) analyse the joint land and water use decision by farmers; (ii) to assess changes in behaviour and production risk in response to water scarcity; and (iii) to understand the limits of applicability of current methods in policy design. We develop a biophysical model of water-limited crop yield building on the AquaCrop model. The model is calibrated and applied to case studies of irrigated corn production in Nebraska and Texas. We run the model iteratively, using long-term climate records, to define two formulations of the crop-water production function: (i) the aggregate relationship between total seasonal irrigation and yield (typical of current approaches); and (ii) the stochastic response of yield and total seasonal irrigation to the choice of an intraseasonal soil moisture target and irrigated area. Irrigated area (the extensive margin decision) and per-area irrigation intensity (the intensive margin decision) are then calculated for different seasonal water restrictions (corresponding to regulatory policies) and well yield constraints on intraseasonal abstraction rates (corresponding to aquifer system limits). Profit- and utility-maximising decisions are determined assuming risk neutrality and varying degrees of risk aversion, respectively. Our results demonstrate that the formulation of the production function has a significant impact on the response to water scarcity. For low well yields, which are the major concern

  6. Experimental determination of viscosity of water based magnetite nanofluid for application in heating and cooling systems

    Science.gov (United States)

    Toghraie, Davood; Alempour, Seyed Mohammadbagher; Afrand, Masoud

    2016-11-01

    In this paper, experimental determination of dynamic viscosity of water based magnetite nanofluid (Fe3O4/water) was performed. The viscosity was measured in the temperature range of 20-55 °C for various samples with solid volume fractions of 0.1%, 0.2%, 0.4%, 1%, 2% and 3%. The results showed that the viscosity considerably decreases with increasing temperature. Moreover, the viscosity enhances with an increase in the solid volume fraction, remarkably. The calculated viscosity ratios showed that the maximum viscosity enhancement was 129.7%. Using experimental data, a new correlation has been proposed to predict the viscosity of magnetite nanofluid (Fe3O4/water). A comparison between the experimental results and the correlation outputs showed that the proposed model has a suitable accuracy.

  7. Experimental infrared measurements for hydrocarbon pollutant determination in subterranean waters.

    Science.gov (United States)

    Lay-Ekuakille, A; Palamara, I; Caratelli, D; Morabito, F C

    2013-01-01

    Subterranean waters are often polluted by industrial and anthropic effluents that are drained in subsoil. To prevent and control pollution, legislations of different developed countries require an online monitoring measurement, especially for detecting organic solvents (chlorinated and unchlorinated ones). Online measurements include both real-time and no real-time measurements. In general, it is difficult to implement real-time measurements in stricto sensu for online acquisitions on aqueous effluents since they need to be processed by a modeling. This research presents an experimental measurement system based on infrared (IR) spectroscopy for aqueous effluents containing hydrocarbons and capable of displaying excellent values of pollutant concentrations even in instable conditions; the system is able to detect pollutants either in laminar or turbulent flow. The results show the possibility of avoiding the use of "Pitot tube" that is employed to create a stagnation point in order to convert kinetic energy into potential one. This conversion allows the transformation of a turbulent flow in a laminar flow making easy measurement of pollutants included in an aqueous effluent. Obviously, "Pitot tube" is also used for other fluid effluents. The obtained results have been compared with those produced by means of sophisticated IR instrumentation for laboratory applications.

  8. Water effect on peroxy radical measurement by chemical amplification: Experimental determination and chemical mechanism

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The water effect on peroxy radical measurement by chemical amplification was determined experimentally for HO2 and HO2+OH, respectively at room temperature (298±2) K and atmospheric pressure (1×105 Pa). No significant difference in water effect was observed with the type of radicals. A theoretical study of the reaction of HO2·H2O adduct with NO was performed using density functional theory at CCSD(T)/6-311 G(2d, 2p)//B3LYP/6-311 G(2d, 2p) level of theory. It was found that the primary reaction channel for the reaction is HO2·H2O+NO→HNO3+H2O (R4a). On the basis of the theoretical study, the rate constant for (R4a) was calculated using Polyrate Version 8.02 program. The fitted Arrenhnius equation for (R4a) is k = 5.49×107 T 1.03exp(?14798/T) between 200 and 2000 K. A chemical model incorporated with (R4a) was used to simulate the water effect. The water effect curve obtained by the model is in accordance with that of the experiment, suggesting that the water effect is probably caused mainly by (R4a).

  9. Water effect on peroxy radical measurement by chemical amplification: Experimental determination and chemical mechanism

    Institute of Scientific and Technical Information of China (English)

    QI Bin; LIU Lu; CHAO YuTao; WANG ZhuQing; YANG HongYan

    2008-01-01

    The water effect on peroxy radical measurement by chemical amplification was determined experi-mentally for HO2 and HO2+OH, respectively at room temperature (298+9) K and atmospheric pressure (1×105 Pa). No significant difference in water effect was observed with the type of radicals. A theoretical study of the reaction of HO2. H2O adduct with NO was performed using density functional theory at CCSD(T)/6-311 G(2d, 2p)//B3LYPI6-311 G(2d, 2p) level of theory. It was found that the primary reaction channel for the reaction is HO2. H2O+NO→HNO3+H2O (R4a). On the basis of the theoretical study, the rate constant for (R4a) was calculated using Polyrate Version 8.02 program. The fitted Arrenhnius equation for (R4a) is k=5.49×107 T1.03exp(-14798/T) between 200 and 2000 K. A chemical model in-corporated with (R4a) was used to simulate the water effect. The water effect curve obtained by the model is in accordance with that of the experiment, suggesting that the water effect is probably caused mainly by (R4a).

  10. Geochemical Modeling of ILAW Lysimeter Water Extracts

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, Kirk J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-22

    Geochemical modeling results of water extracts from simulated immobilized low-activity waste (ILAW) glasses, placed in lysimeters for eight years suggest that the secondary phase reaction network developed using product consistency test (PCT) results at 90°C may need to be modified for field conditions. For sediment samples that had been collected from near the glass samples, the impact of glass corrosion could be readily observed based upon the pH of their water extracts. For unimpacted sediments the pH ranged from 7.88 to 8.11 with an average of 8.04. Sediments that had observable impacts from glass corrosion exhibited elevated pH values (as high as 9.97). For lysimeter sediment samples that appear to have been impacted by glass corrosion to the greatest extent, saturation indices determined for analcime, calcite, and chalcedony in the 1:1 water extracts were near equilibrium and were consistent with the secondary phase reaction network developed using PCT results at 90°C. Fe(OH)3(s) also appears to be essentially at equilibrium in extracts impacted by glass corrosion, but with a solubility product (log Ksp) that is approximately 2.13 units lower than that used in the secondary phase reaction network developed using PCT results at 90°C. The solubilities of TiO2(am) and ZrO2(am) also appear to be much lower than that assumed in the secondary phase reaction network developed using PCT results at 90°C. The extent that the solubility of TiO2(am) and ZrO2(am) were reduced relative to that assumed in the secondary phase reaction network developed using PCT results at 90°C could not be quantified because the concentrations of Ti and Zr in the extracts were below the estimated quantification limit. Gibbsite was consistently highly oversaturated in the extract while dawsonite was at or near equilibrium. This suggests that dawsonite might be a more suitable phase for the secondary phase reaction network

  11. Understanding transport in model water desalination membranes

    Science.gov (United States)

    Chan, Edwin

    Polyamide based thin film composites represent the the state-of-the-art nanofiltration and reverse osmosis membranes used in water desalination. The performance of these membranes is enabled by the ultrathin (~100 nm) crosslinked polyamide film in facilitating the selective transport of water over salt ions. While these materials have been refined over the last several decades, understanding the relationships between polyamide structure and membrane performance remains a challenge because of the complex and heterogeneous nature of the polyamide film. In this contribution, we present our approach to addressing this challenge by studying the transport properties of model polyamide membranes synthesized via molecular layer-by-layer (mLbL) assembly. First, we demonstrate that mLbL can successfully construct polyamide membranes with well-defined nanoscale thickness and roughness using a variety of monomer formulations. Next, we present measurement tools for characterizing the network structure and transport of these model polyamide membranes. Specifically, we used X-ray and neutron scattering techniques to characterize their structure as well as a recently-developed indentation based poromechanics approach to extrapolate their water diffusion coefficient. Finally, we illustrate how these measurements can provide insight into the original problem by linking the key polyamide network properties, i.e. water-polyamide interaction parameter and characteristic network mesh size, to the membrane performance.

  12. A Quick Dielectric Method to Determine Insitu Soil Water Content for Precision Water Use under Sustainable Agricultural Practices

    Directory of Open Access Journals (Sweden)

    Bandi Hermawan

    2017-06-01

    Full Text Available Precise water use systems under sustainable agriculture may only be achieved if in-situ soil water content and availability of the plant can be measured quickly.  Soil water content can be determined directly using the gravimetrical method by calculating the loss of water when the soil dries out, and indirectly by measuring other variables from which soil water can be calculated.  The indirect methods have some advantages when compared to the direct gravimetrical method because measured; non-destructive soil water data are available instantly.  Soil dielectric properties have strong relationships with soil water content and have been used widely as indirect methods of soil water determination, but the cost of the available instrument is too expensive for small-scale farmers.  Two studies were conducted in 2011 and 2015 to develop a quick, cheap method to determine in-situ soil water content and precise water use by crops.  The method applied a non-linear relation between soil water content (θ, in gg-1 and soil electrical impedance (Z, in kΩ as follows: θ = a.Zb where a and b are constants.  Parameter Z showed a good predictor for soil water content (R ≥ 0.90 therefore can be used to quickly determine soil water content in the field.  The dielectric method has been successfully used to determine the water balance in the vegetated soils, in wich changes in soil water content caused by daily rainfall as low as 10 mm was detected up to the depth of 60 cm.  The method was also successfully capable of calculating the amount of water used by palm oil nursery grown in media with different levels of soil organic matter.

  13. Modeling regulated water utility investment incentives

    Science.gov (United States)

    Padula, S.; Harou, J. J.

    2014-12-01

    This work attempts to model the infrastructure investment choices of privatized water utilities subject to rate of return and price cap regulation. The goal is to understand how regulation influences water companies' investment decisions such as their desire to engage in transfers with neighbouring companies. We formulate a profit maximization capacity expansion model that finds the schedule of new supply, demand management and transfer schemes that maintain the annual supply-demand balance and maximize a companies' profit under the 2010-15 price control process in England. Regulatory incentives for costs savings are also represented in the model. These include: the CIS scheme for the capital expenditure (capex) and incentive allowance schemes for the operating expenditure (opex) . The profit-maximizing investment program (what to build, when and what size) is compared with the least cost program (social optimum). We apply this formulation to several water companies in South East England to model performance and sensitivity to water network particulars. Results show that if companies' are able to outperform the regulatory assumption on the cost of capital, a capital bias can be generated, due to the fact that the capital expenditure, contrarily to opex, can be remunerated through the companies' regulatory capital value (RCV). The occurrence of the 'capital bias' or its entity depends on the extent to which a company can finance its investments at a rate below the allowed cost of capital. The bias can be reduced by the regulatory penalties for underperformances on the capital expenditure (CIS scheme); Sensitivity analysis can be applied by varying the CIS penalty to see how and to which extent this impacts the capital bias effect. We show how regulatory changes could potentially be devised to partially remove the 'capital bias' effect. Solutions potentially include allowing for incentives on total expenditure rather than separately for capex and opex and allowing

  14. Determining water use of sorghum from two-source energy balance and radiometric temperatures

    Directory of Open Access Journals (Sweden)

    J. M. Sánchez

    2011-10-01

    Full Text Available Estimates of surface actual evapotranspiration (ET can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB model was evaluated by comparison of estimated ET with values measured on a weighing lysimeter. Errors of ±0.14 mm h−1 and ±1.0 mm d−1 were obtained at hourly and daily scales, respectively. Total accumulated crop water use during the campaign was underestimated by 5%. It is then shown that thermal radiometry can provide precise crop water necessities and is a promising tool for irrigation management.

  15. Determining water use of sorghum from two-source energy balance and radiometric temperatures

    Science.gov (United States)

    Sánchez, J. M.; López-Urrea, R.; Rubio, E.; Caselles, V.

    2011-10-01

    Estimates of surface actual evapotranspiration (ET) can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor) field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB) model was evaluated by comparison of estimated ET with values measured on a weighing lysimeter. Errors of ±0.14 mm h-1 and ±1.0 mm d-1 were obtained at hourly and daily scales, respectively. Total accumulated crop water use during the campaign was underestimated by 5%. It is then shown that thermal radiometry can provide precise crop water necessities and is a promising tool for irrigation management.

  16. Advances in the Coupled Soil Water and Groundwater Models

    Institute of Scientific and Technical Information of China (English)

    杨玉峥; 王志敏

    2014-01-01

    Models simulating the reciprocal transformation between the soil water and groundwater are of great practical importance to the development and utilization of water resources and prevention and remedy of water pollution. In this paper, popular coupled models of soil water and groundwater will be analyzed. Besides, advantages and disadvantages of different models will be summarized as a reference for the numerical model of soil water and groundwater.

  17. Patterns of local and nonlocal water resource use across the western U.S. determined via stable isotope intercomparisons

    Science.gov (United States)

    Good, Stephen P.; Kennedy, Casey D.; Stalker, Jeremy C.; Chesson, Lesley A.; Valenzuela, Luciano O.; Beasley, Melanie M.; Ehleringer, James R.; Bowen, Gabriel. J.

    2014-10-01

    In the western U.S., the mismatch between public water demands and natural water availability necessitates large interbasin transfers of water as well as groundwater mining of fossil aquifers. Here we identify probable situations of nonlocal water use in both space and time based on isotopic comparisons between tap waters and potential water resources within hydrologic basins. Our approach, which considers evaporative enrichment of heavy isotopes during storage and distribution, is used to determine the likelihood of local origin for 612 tap water samples collected from across the western U.S. We find that 64% of samples are isotopically distinct from precipitation falling within the local hydrologic basin, a proxy for groundwater with modern recharge, and 31% of samples are isotopically distinct from estimated surface water found within the local basin. Those samples inconsistent with local water sources, which we suggest are likely derived from water imported from other basins or extracted from fossil aquifers, are primarily clustered in southern California, the San Francisco Bay area, and central Arizona. Our isotope-based estimates of nonlocal water use are correlated with both hydrogeomorphic and socioeconomic properties of basins, suggesting that these factors exert a predictable influence on the likelihood that nonlocal waters are used to supply tap water. We use these basin properties to develop a regional model of nonlocal water resource use that predicts (r2 = 0.64) isotopically inferred patterns and allows assessment of total interbasin transfer and/or fossil aquifer extraction volumes across the western U.S.

  18. A novel domestic electric water heater model for a multi-objective demand side management program

    Energy Technology Data Exchange (ETDEWEB)

    Paull, Liam; Li, Howard; Chang, Liuchen [University of New Brunswick, Department of Electrical Engineering, Fredericton, NB (Canada)

    2010-12-15

    This paper presents a novel domestic hot water heater model to be used in a multi-objective demand side management program. The model incorporates both the thermal losses and the water usage to determine the temperature of the water in the tank. Water heater loads are extracted from household load data and then used to determine the household water usage patterns. The benefits of the model are: (1) the on/off state of the water heater and temperature of the water in the tank can be accurately predicted, and (2) it enables the development of water usage profiles so that users can be classified based on usage behaviour. As a result, the amount of ancillary services and peak shaving that can be achieved are accurately predictable and can be maximized without adversely affecting users. (author)

  19. Multi-agent immune recognition of water mine model

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-bo; GU Guo-chang; SHEN Jing; FU Yan

    2005-01-01

    It is necessary for mine countermeasure systems to recognise the model of a water mine before destroying because the destroying measures to be taken must be determined according to mine model. In this paper, an immune neural network (INN) along with water mine model recognition system based on multi-agent system is proposed. A modified clonal selection algorithm for constructing such an INN is presented based on clonal selection principle. The INN is a two-layer Boolean network whose number of outputs is adaptable according to the task and the affinity threshold. Adjusting the affinity threshold can easily control different recognition precision, and the affinity threshold also can control the capability of noise tolerance.

  20. Rapid, quantitative determination of bacteria in water. [adenosine triphosphate

    Science.gov (United States)

    Chappelle, E. W.; Picciolo, G. L.; Thomas, R. R.; Jeffers, E. L.; Deming, J. W. (Inventor)

    1978-01-01

    A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are presented so that the light output can be correlated to bacteria in the sample and system noise can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction.

  1. Electron Delocalization Determined Anomalous Stability in Small Water Rings

    CERN Document Server

    Wang, Bo; Dai, Xing; Song, Ruixia; Meng, Yan; Wang, Zhigang; Zhang, Ruiqin

    2013-01-01

    Water clusters are known to form through hydrogen bonding. However, this study shows that the formation of very small water clusters significantly deviates from this mechanism and instead involves both hydrogen bonding and electron delocalization. Our density functional theory calculations show that small water rings (H2O)n of n=3 or 4 show strong electron delocalization originating from both the hydrogen and oxygen atoms and extending to the ring center. This is very different from larger rings. Further energy decomposition of rings with n=3-6 demonstrates an upward trend in the polarization component but an decrease in the electrostatic and exchange repulsion components, presenting a minimum and accounting for 33% of interaction energy at n=3. This significantly promotes stability of the small water rings. Our findings provide a comprehensive analysis and improve our understanding of the stability characteristics of water clusters.

  2. Determination of viable legionellae in engineered water systems: Do we find what we are looking for?

    Science.gov (United States)

    Kirschner, Alexander K T

    2016-04-15

    In developed countries, legionellae are one of the most important water-based bacterial pathogens caused by management failure of engineered water systems. For routine surveillance of legionellae in engineered water systems and outbreak investigations, cultivation-based standard techniques are currently applied. However, in many cases culture-negative results are obtained despite the presence of viable legionellae, and clinical cases of legionellosis cannot be traced back to their respective contaminated water source. Among the various explanations for these discrepancies, the presence of viable but non-culturable (VBNC) Legionella cells has received increased attention in recent discussions and scientific literature. Alternative culture-independent methods to detect and quantify legionellae have been proposed in order to complement or even substitute the culture method in the future. Such methods should detect VBNC Legionella cells and provide a more comprehensive picture of the presence of legionellae in engineered water systems. However, it is still unclear whether and to what extent these VBNC legionellae are hazardous to human health. Current risk assessment models to predict the risk of legionellosis from Legionella concentrations in the investigated water systems contain many uncertainties and are mainly based on culture-based enumeration. If VBNC legionellae should be considered in future standard analysis, quantitative risk assessment models including VBNC legionellae must be proven to result in better estimates of human health risk than models based on cultivation alone. This review critically evaluates current methods to determine legionellae in the VBNC state, their potential to complement the standard culture-based method in the near future, and summarizes current knowledge on the threat that VBNC legionellae may pose to human health.

  3. Monthly Water Balance Model Hydrology Futures

    Science.gov (United States)

    Bock, Andy; Hay, Lauren E.; Markstrom, Steven; Atkinson, R. Dwight

    2016-01-01

    A monthly water balance model (MWBM) was driven with precipitation and temperature using a station-based dataset for current conditions (1950 to 2010) and selected statistically-downscaled general circulation models (GCMs) for current and future conditions (1950 to 2099) across the conterminous United States (CONUS) using hydrologic response units from the Geospatial Fabric for National Hydrologic Modeling (http://dx.doi.org/doi:10.5066/F7542KMD). Six MWBM output variables (actual evapotranspiration (AET), potential evapotranspiration (PET), runoff (RO), streamflow (STRM), soil moisture storage (SOIL), and snow water equivalent (SWE)) and the two MWBM input variables (atmospheric temperature (TAVE) and precipitation (PPT)) were summarized for hydrologic response units and aggregated at points of interest on a stream network. Results were then organized into the Monthly Water Balance Hydrology Futures database, an open-access database using netCDF format (http://cida-eros-mows1.er.usgs.gov/thredds/dodsC/nwb_pub/).  Methods used to calibrate and parameterize the MWBM are detailed in the Hydrology and Earth System Sciences (HESS)  paper "Parameter regionalization of a monthly water balance model for the conterminous United States" by Bock and others (2016).  See the discussion paper link in the "Related External Resources" section for access.  Supplemental data files related to the plots and data analysis in Bock and others (2016) can be found in the HESS-2015-325.zip folder in the "Attached Files" section.  Detailed information on the files and data can be found in the ReadMe.txt contained within the zipped folder. Recommended citation of discussion paper:Bock, A.R., Hay, L.E., McCabe, G.J., Markstrom, S.L., and Atkinson, R.D., 2016, Parameter regionalization of a monthly water balance model for the conterminous United States: Hydrology and Earth System Sciences, v. 20, 2861-2876, doi:10.5194/hess-20-2861-2016, 2016

  4. 18 CFR 430.7 - Determination of protected areas and restriction on water use.

    Science.gov (United States)

    2010-04-01

    ... supplies have developed or threaten to develop to such a degree as to create a water shortage or to impair... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Determination of protected areas and restriction on water use. 430.7 Section 430.7 Conservation of Power and Water Resources...

  5. Determining the effect of climate change and development on water resources management in the Sudan

    Science.gov (United States)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2013-12-01

    The effects of development and the uncertainty of climate change in East Africa provide a myriad of challenges for water managers along the Blue Nile. The construction of the Grand renaissance dam (GRD), as well as the unknown trajectory of precipitation trends in the Ethiopian highlands may greatly affect the countries that rely on the Nile. Sudan's huge irrigation potential and dams that feed multiple current irrigation schemes as well as its location within the basin means that Sudan's water management decisions may reverberate and have social, economic and political implications within the east African sub-region. Here, we apply a suite of state-of-the-art hydrology and climate analysis tools to evaluate the sensitivity of Sudan's optimal hydropower and irrigation development pathways to hydrologic variability and climate change. Present day hydrologic conditions are derived from a gridded implementation of the Noah Land Surface Model (LSM) that includes representation of typical irrigation practices in the region. Noah is implemented using the NASA Land Information System (LIS), and draws forcing data from a combination of reanalysis and satellite meteorological products. Additional satellite inputs are used to provide a constraint on Noah evapotranspiration estimates and to acquire parameters such as crop water requirements that are crucial in determining yield and agricultural production. Future climate conditions are projected using statistical downscaling techniques trained to historical meteorological records and projected forward using inputs from the 5th Coupled Model Intercomparison Project (CMIP5) simulation database. These climatic and hydrologic inputs are combined with agronomic and economic inputs to drive an optimization model developed within the General Algebraic Modeling System (GAMS). By using output and results from climate, hydrologic and optimization models this research aims to show how these models can be integrated to aid decision

  6. Modeling Soil Water Retention Curve with a Fractal Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Many empirical models have been developed to describe the soil water retention curve (SWRC). In this study, a fractal model for SWRC was derived with a specially constructed Menger sponge to describe the fractal scaling behavior of soil; relationships were established among the fractal dimension of SWRC, the fractal dimension of soil mass, and soil texture; and the model was used to estimate SWRC with the estimated results being compared to experimental data for verification. The derived fractal model was in a power-law form, similar to the Brooks-Corey and Campbell empirical functions. Experimental data of particle size distribution (PSD), texture, and soil water retention for 10 soils collected at different places in China were used to estimate the fractal dimension of SWRC and the mass fractal dimension. The fractal dimension of SWRC and the mass fractal dimension were linearly related. Also, both of the fractal dimensions were dependent on soil texture, i.e., clay and sand contents. Expressions were proposed to quantify the relationships. Based on the relationships, four methods were used to determine the fractal dimension of SWRC and the model was applied to estimate soil water content at a wide range of tension values. The estimated results compared well with the measured data having relative errors less than 10% for over 60% of the measurements. Thus, this model, estimating the fractal dimension using soil textural data, offered an alternative for predicting SWRC.

  7. Improving macroscopic modeling of the effect of water and osmotic stresses on root water uptake.

    Science.gov (United States)

    Jorda Guerra, Helena; Vanderborght, Jan

    2015-04-01

    Accurate modeling of water and salt stresses on root water uptake is critical for predicting impacts of global change and climate variability on crop production and soil water balances. Soil-hydrological models use reduction functions to represent the effect of osmotic stress in transpiration. However, these functions, which were developed empirically, present limitations in relation to the time and spatial scale at which they need to be used, fail to include compensation processes and do not agree on how water and salt stresses interact. This research intends to develop a macroscopic reduction function for water and osmotic stresses based on biophysical knowledge. Simulation experiments are conducted for a range of atmospheric conditions, soil and plant properties, irrigation water quality and scheduling using a 3-D physically-based model that resolves flow and transport to individual root segments and that couples flow in the soil and root system (Schröder et al., 2013). The effect of salt concentrations on water flow in the soil-root system is accounted for by including osmotic water potential gradients between the solution at the soil root interface and the root xylem sap in the hydraulic gradient between the soil and root. In a first step, simulation experiments are carried out in a soil volume around a single root segment. We discuss how the simulation setup can be defined so as to represent: (i) certain characteristics of the root system such as rooting depth and root length density, (ii) plant transpiration rate, (iii) leaching fraction of the irrigation, and (iii) salinity of the irrigation water. The output of these simulation experiments gives a first insight in the effect of salinity on transpiration and on the relation between the bulk salinity in the soil voxel, which is used in macroscopic salt stress functions of models that do not resolve processes at the root segment scale, and the salinity at the soil-root interface, which determines the actual

  8. Informal household water market and determinants of price: Evidence from an Indian hill city

    Science.gov (United States)

    Pal, Manoranjan; De, Utpal Kumar

    2015-02-01

    Pricing of water in the hill cities in India is different from that of plain lands, because water is a scarce resource in most of the hill cities. The supply of water by the municipalities is inadequate. The private vendors come into picture and they put the prices according to the difficulties faced in supplying to the specific locations. Thus prices become variables and are also based on the economic demand-supply mechanism in which the households try to maximise their satisfaction subject to budget and other constraints, while the vendors try to extract as much benefit as possible from the buyers. This paper tries to examine the pricing of household water use in Shillong urban area, India and the impact of various factors including income, house rent, seasonal scarcity of water, capacity of municipal supply, household size on the price-quantity determination. The analysis is made in terms of a simultaneous equation framework and the model is applied to a data collected by stratified random sampling technique across the municipal wards and non-municipal segments of greater Shillong urban Agglomeration. The result of three stage least squares reveals significant positive impacts of income, scarcity of water on the demand price while significantly negative impacts of quantity purchased, extent of municipal supply, house rent paid on the demand price. But the household size does not have any significant impact on the demand price though large household is expected to require more water. The supply of water on the other hand is not significantly affected by price, extent of municipal supply and deficiency though the coefficients are in the expected line.

  9. Determination of the IGRF 2000 model

    DEFF Research Database (Denmark)

    Olsen, Nils; Sabaka, T.J.; Tøffner-Clausen, Lars

    2000-01-01

    The IGRF 2000 has been estimated from magnetic measurements taken by the Orsted sattelite in summer 1999. For this purpose, three models have been derived: The first two models were estimated using a few geomagnetic quiet days in May and September 1999, respectively. The third model, called Oerst...

  10. Adaptive Control and Synchronization of the Shallow Water Model

    Directory of Open Access Journals (Sweden)

    P. Sangapate

    2012-01-01

    Full Text Available The shallow water model is one of the important models in dynamical systems. This paper investigates the adaptive chaos control and synchronization of the shallow water model. First, adaptive control laws are designed to stabilize the shallow water model. Then adaptive control laws are derived to chaos synchronization of the shallow water model. The sufficient conditions for the adaptive control and synchronization have been analyzed theoretically, and the results are proved using a Barbalat's Lemma.

  11. Determination of Consumers’ Demand on Water Buffalo Products

    OpenAIRE

    AZABAĞAOĞLU, M. Ömer; HURMA, Harun

    2016-01-01

    Water Buffalo whose 96.4% population is present in Asia is breed for its meat, leather and labor.When compared to cow’s milk, water buffalo milk is preferred in dairy technology since it has highfeeding properties and contains less water, higher brix level, fat, protein, and lactose. Buffalo milk ismarketed to the consumers as cream, butter, yoghurt or milk by the producers and local dairies.Nowadays, these products that are available to consumers mainly in local markets can also be found ins...

  12. Water adsorption on goethite: Application of multilayer adsorption models

    Science.gov (United States)

    Hatch, C. D.; Tumminello, R.; Meredith, R.

    2016-12-01

    Adsorbed water on the surface of atmospheric mineral dust has recently been shown to significantly affect the ability of mineral dust aerosol to act as cloud condensation nuclei. We have studied water adsorption as a function of relative humidity (RH) on goethite (α-FeO(OH)), a common component of atmospheric mineral dust. The goethite surface area and particle size was determined using BET analysis and with N2 as an adsorbate and scanning electron microscopy, respectively. Water adsorption on the sample was monitored using horizontal attenuated total reflectance Fourier transform infrared (HATR-FTIR) spectroscopy equipped with a flow cell. Water content was determined using Beer's law and the optical constants for bulk water. The results were analyzed using Type II adsorption isotherms to model multilayer adsorption, including BET (Brunauer, Emmet and Teller), FHH (Frenkel, Halsey and Hill) and Freundlich. BET fits to experimental data provide parameters of monolayer coverage, while the FHH and Freundlich isotherms provide insights into multilayer adsorption mechanisms. Results indicate that goethite contains 5% H2O by mass at 50% RH, which increases to 12% by mass at 90% RH. Adsorption parameters and experimental results will be presented.

  13. Environmental Modeling, Florida Adopted TMDLs. What is a TMDL (Total Maximum Daily Load)? A scientific determination of the maximum amount of a given pollutant that a surface water can absorb and still meet the water quality standards that protect human health and aquatic life., Published in 1999, 1:24000 (1in=2000ft) scale, Florida Department of Environmental Protection (FDEP).

    Data.gov (United States)

    NSGIC State | GIS Inventory — Environmental Modeling dataset current as of 1999. Florida Adopted TMDLs. What is a TMDL (Total Maximum Daily Load)? A scientific determination of the maximum amount...

  14. Hyperspectral Remote Sensing for Shallow Waters. I. A Semianalytical Model

    Science.gov (United States)

    Lee, Zhongping; Carder, Kendall L.; Mobley, Curtis D.; Steward, Robert G.; Patch, Jennifer S.

    1998-09-01

    For analytical or semianalytical retrieval of shallow-water bathymetry and or optical properties of the water column from remote sensing, the contribution to the remotely sensed signal from the water column has to be separated from that of the bottom. The mathematical separation involves three diffuse attenuation coefficients: one for the downwelling irradiance ( K d ), one for the upwelling radiance of the water column ( K u C ), and one for the upwelling radiance from bottom reflection ( K u B ). Because of the differences in photon origination and path lengths, these three coefficients in general are not equal, although their equality has been assumed in many previous studies. By use of the Hydrolight radiative-transfer numerical model with a particle phase function typical of coastal waters, the remote-sensing reflectance above ( R rs ) and below ( r rs ) the surface is calculated for various combinations of optical properties, bottom albedos, bottom depths, and solar zenith angles. A semianalytical (SA) model for r rs of shallow waters is then developed, in which the diffuse attenuation coefficients are explicitly expressed as functions of in-water absorption ( a ) and backscattering ( b b ). For remote-sensing inversion, parameters connecting R rs and r rs are also derived. It is found that r rs values determined by the SA model agree well with the exact values computed by Hydrolight ( 3% error), even for Hydrolight r rs values calculated with different particle phase functions. The Hydrolight calculations included b b a values as high as 1.5 to simulate high-turbidity situations that are occasionally found in coastal regions.

  15. Experimental infrared measurements for hydrocarbon pollutant determination in subterranean waters

    NARCIS (Netherlands)

    Lay-Ekuakille, A.; Palamara, I.; Caratelli, D.; Morabito, F.C.

    2013-01-01

    Subterranean waters are often polluted by industrial and anthropic effluents that are drained in subsoil. To prevent and control pollution, legislations of different developed countries require an online monitoring measurement, especially for detecting organic solvents (chlorinated and unchlorinated

  16. water quality determination of rainwater harvesting birkas in harshin ...

    African Journals Online (AJOL)

    Osondu

    2012-03-14

    Mar 14, 2012 ... drinking water and accompanying illnesses live in Asia and Africa among which majority of .... explained in Bartram and Balance (1996) was followed. The sample ... potential to cause central nervous system damage will be ...

  17. trace elements determination in municipal water supply in damaturu ...

    African Journals Online (AJOL)

    DR. AMINU

    Key words: Contamination, Trace elements, Toxic, underground water. INTRODUCTION ... prevent rot and increase longevity, such as penta- ... often contains arsenic that was in drugs administered to chickens .... could cause toxicity. Iron was ...

  18. A rapid method for determining chlorobenzenes in dam water systems

    African Journals Online (AJOL)

    2012-04-16

    Apr 16, 2012 ... KG Moodley1*, DK Chetty1, SR Ramphal1 and G Gericke2 ... materials in the manufacture of pesticides, chlorinated phenols, lubricants ...... Engineers, Jeffares and Green, Sechaba Consulting, WCE (Pty.) Ltd. and Water ...

  19. Source determination of polynuclear aromatic hydrocarbons in water ...

    African Journals Online (AJOL)

    SERVER

    2008-02-05

    Feb 5, 2008 ... African Journal of Biotechnology Vol. 7 (3), pp. 282-285, 5 ... Polynuclear aromatic hydrocarbons in surface water and sediment of Ekpan Creek of the Warri River ... contaminated with industrial PAHs wastes have directly.

  20. Determination of selected heavy metals in inland fresh water of ...

    African Journals Online (AJOL)

    Agadaga

    significant negative impact on the water quality. Key words: Heavy ... fish, and for such in-stream uses as recreation, ... adverse effects of pollutants such as heavy metals is ... through Kebbi State and flows through to the Atlantic Ocean. The.

  1. Determination of water quality index and portability of Iguedo stream ...

    African Journals Online (AJOL)

    ... copper, lead, manganese, nickel, cadmium and chromium characterized in three ... With the exception of nickel other physicochemical parameters characterized ... that the water quality at station 1 was poor while stations 2 and 3 were good.

  2. IAEA proficiency tests for determination of radionuclides in sea water.

    Science.gov (United States)

    Harms, Arend; Khanh Pham, Mai; Blinova, Oxana; Tarjan, Sandor; Nies, Hartmut; Osvath, Iolanda

    2017-08-01

    The International Atomic Energy Agency organised four proficiency tests between 2012 and 2015 to test the performance of participating laboratories in an analysis of radionuclides in sea water samples. These exercises were initiated to support IAEA Member States in sea water analyses of tritium, strontium-90 and caesium isotopes in relation to the accident at the Fukushima Daiichi nuclear power station, in March 2011, and subsequent contamination of the marine environment. Copyright © 2017. Published by Elsevier Ltd.

  3. A Data Mining Approach to Modelling of Water Supply Assets

    DEFF Research Database (Denmark)

    Babovic, V.; Drecourt, J.; Keijzer, M.

    2002-01-01

    supply assets are mainly situated underground, and therefore not visible and under the influence of various highly unpredictable forces. This paper proposes the use of advanced data mining methods in order to determine the risks of pipe bursts. For example, analysis of the database of already occurred...... with the choice of pipes to be replaced, the outlined approach opens completely new avenues in asset modelling. The condition of an asset such as a water supply network deteriorates with age. With reliable risk models, addressing the evolution of risk with aging asset, it is now possible to plan optimal...

  4. Lattice Boltzmann modeling of water entry problems

    Science.gov (United States)

    Zarghami, A.; Falcucci, G.; Jannelli, E.; Succi, S.; Porfiri, M.; Ubertini, S.

    2014-12-01

    This paper deals with the simulation of water entry problems using the lattice Boltzmann method (LBM). The dynamics of the free surface is treated through the mass and momentum fluxes across the interface cells. A bounce-back boundary condition is utilized to model the contact between the fluid and the moving object. The method is implemented for the analysis of a two-dimensional flow physics produced by a symmetric wedge entering vertically a weakly-compressible fluid at a constant velocity. The method is used to predict the wetted length, the height of water pile-up, the pressure distribution and the overall force on the wedge. The accuracy of the numerical results is demonstrated through comparisons with data reported in the literature.

  5. Underwater light field determined by water constituents in highly turbid water: the case of Taihu lake

    Directory of Open Access Journals (Sweden)

    Chang-Chun Huang

    2013-02-01

    . Overall, the knowledge of the bio-optical properties obtained in this study extends our understanding of water optics and can be used to predict the optical properties via water constituent concentration, regardless of measurement type (in situ or simulated by hydrodynamic model.

  6. Ocean modelling for aquaculture and fisheries in Irish waters

    Science.gov (United States)

    Dabrowski, T.; Lyons, K.; Cusack, C.; Casal, G.; Berry, A.; Nolan, G. D.

    2016-01-01

    The Marine Institute, Ireland, runs a suite of operational regional and coastal ocean models. Recent developments include several tailored products that focus on the key needs of the Irish aquaculture sector. In this article, an overview of the products and services derived from the models are presented. The authors give an overview of a shellfish model developed in-house and that was designed to predict the growth, the physiological interactions with the ecosystem, and the level of coliform contamination of the blue mussel. As such, this model is applicable in studies on the carrying capacity of embayments, assessment of the impacts of pollution on aquaculture grounds, and the determination of shellfish water classes. Further services include the assimilation of the model-predicted shelf water movement into a new harmful algal bloom alert system used to inform end users of potential toxic shellfish events and high biomass blooms that include fish-killing species. Models are also used to identify potential sites for offshore aquaculture, to inform studies of potential cross-contamination in farms from the dispersal of planktonic sea lice larvae and other pathogens that can infect finfish, and to provide modelled products that underpin the assessment and advisory services on the sustainable exploitation of the resources of marine fisheries. This paper demonstrates that ocean models can provide an invaluable contribution to the sustainable blue growth of aquaculture and fisheries.

  7. Climate change, livelihoods and the multiple determinants of water adequacy: two approaches at regional to global scale

    Science.gov (United States)

    Lissner, Tabea; Reusser, Dominik

    2015-04-01

    Inadequate access to water is already a problem in many regions of the world and processes of global change are expected to further exacerbate the situation. Many aspects determine the adequacy of water resources: beside actual physical water stress, where the resource itself is limited, economic and social water stress can be experienced if access to resource is limited by inadequate infrastructure, political or financial constraints. To assess the adequacy of water availability for human use, integrated approaches are needed that allow to view the multiple determinants in conjunction and provide sound results as a basis for informed decisions. This contribution proposes two parts of an integrated approach to look at the multiple dimensions of water scarcity at regional to global scale. These were developed in a joint project with the German Development Agency (GIZ). It first outlines the AHEAD approach to measure Adequate Human livelihood conditions for wEll-being And Development, implemented at global scale and at national resolution. This first approach allows viewing impacts of climate change, e.g. changes in water availability, within the wider context of AHEAD conditions. A specific focus lies on the uncertainties in projections of climate change and future water availability. As adequate water access is not determined by water availability alone, in a second step we develop an approach to assess the water requirements for different sectors in more detail, including aspects of quantity, quality as well as access, in an integrated way. This more detailed approach is exemplified at region-scale in Indonesia and South Africa. Our results show that in many regions of the world, water scarcity is a limitation to AHEAD conditions in many countries, regardless of differing modelling output. The more detailed assessments highlight the relevance of additional aspects to assess the adequacy of water for human use, showing that in many regions, quality and

  8. Evaluating Water Demand Using Agent-Based Modeling

    Science.gov (United States)

    Lowry, T. S.

    2004-12-01

    The supply and demand of water resources are functions of complex, inter-related systems including hydrology, climate, demographics, economics, and policy. To assess the safety and sustainability of water resources, planners often rely on complex numerical models that relate some or all of these systems using mathematical abstractions. The accuracy of these models relies on how well the abstractions capture the true nature of the systems interactions. Typically, these abstractions are based on analyses of observations and/or experiments that account only for the statistical mean behavior of each system. This limits the approach in two important ways: 1) It cannot capture cross-system disruptive events, such as major drought, significant policy change, or terrorist attack, and 2) it cannot resolve sub-system level responses. To overcome these limitations, we are developing an agent-based water resources model that includes the systems of hydrology, climate, demographics, economics, and policy, to examine water demand during normal and extraordinary conditions. Agent-based modeling (ABM) develops functional relationships between systems by modeling the interaction between individuals (agents), who behave according to a probabilistic set of rules. ABM is a "bottom-up" modeling approach in that it defines macro-system behavior by modeling the micro-behavior of individual agents. While each agent's behavior is often simple and predictable, the aggregate behavior of all agents in each system can be complex, unpredictable, and different than behaviors observed in mean-behavior models. Furthermore, the ABM approach creates a virtual laboratory where the effects of policy changes and/or extraordinary events can be simulated. Our model, which is based on the demographics and hydrology of the Middle Rio Grande Basin in the state of New Mexico, includes agent groups of residential, agricultural, and industrial users. Each agent within each group determines its water usage

  9. Modelling of bio-optical parameters of open ocean waters

    Directory of Open Access Journals (Sweden)

    Vadim N. Pelevin

    2001-12-01

    Full Text Available An original method for estimating the concentration of chlorophyll pigments, absorption of yellow substance and absorption of suspended matter without pigments and yellow substance in detritus using spectral diffuse attenuation coefficient for downwelling irradiance and irradiance reflectance data has been applied to sea waters of different types in the open ocean (case 1. Using the effective numerical single parameter classification with the water type optical index m as a parameter over the whole range of the open ocean waters, the calculations have been carried out and the light absorption spectra of sea waters tabulated. These spectra are used to optimize the absorption models and thus to estimate the concentrations of the main admixtures in sea water. The value of m can be determined from direct measurements of the downward irradiance attenuation coefficient at 500 nm or calculated from remote sensing data using the regressions given in the article. The sea water composition can then be readily estimated from the tables given for any open ocean area if that one parameter m characterizing the basin is known.

  10. Modeling water emission from low-mass protostellar envelopes

    CERN Document Server

    van Kempen, T A; Van Dishoeck, E F; Hogerheijde, M R; Jørgensen, J K

    2008-01-01

    Within low-mass star formation, water vapor plays a key role in the chemistry and energy balance of the circumstellar material. The Herschel Space Observatory will open up the possibility to observe water lines originating from a wide range of excitation energies.Our aim is to simulate the emission of rotational water lines from envelopes characteristic of embedded low-mass protostars. A large number of parameters that influence the water line emission are explored: luminosity, density,density slope and water abundances.Both dust and water emission are modelled using full radiative transfer in spherical symmetry. The temperature profile is calculated for a given density profile. The H2O level populations and emission profiles are in turn computed with a non-LTE line code. The results are analyzed to determine the diagnostic value of different lines, and are compared with existing observations. Lines can be categorized in: (i) optically thick lines, including ground-state lines, mostly sensitive to the cold ou...

  11. Ground-water models: Validate or invalidate

    Science.gov (United States)

    Bredehoeft, J.D.; Konikow, L.F.

    1993-01-01

    The word validation has a clear meaning to both the scientific community and the general public. Within the scientific community the validation of scientific theory has been the subject of philosophical debate. The philosopher of science, Karl Popper, argued that scientific theory cannot be validated, only invalidated. Popper’s view is not the only opinion in this debate; however, many scientists today agree with Popper (including the authors). To the general public, proclaiming that a ground-water model is validated carries with it an aura of correctness that we do not believe many of us who model would claim. We can place all the caveats we wish, but the public has its own understanding of what the word implies. Using the word valid with respect to models misleads the public; verification carries with it similar connotations as far as the public is concerned. Our point is this: using the terms validation and verification are misleading, at best. These terms should be abandoned by the ground-water community.

  12. Modeling terahertz heating effects on water

    DEFF Research Database (Denmark)

    Kristensen, Torben T.L.; Withayachumnankul, Withawat; Jepsen, Peter Uhd;

    2010-01-01

    We apply Kirchhoff’s heat equation to model the influence of a CW terahertz beam on a sample of water, which is assumed to be static. We develop a generalized model, which easily can be applied to other liquids and solids by changing the material constants. If the terahertz light source is focused...... down to a spot with a diameter of 0.5 mm, we find that the steadystate temperature increase per milliwatt of transmitted power is 1.8◦C/mW. A quantum cascade laser can produce a CW beam in the order of several milliwatts and this motivates the need to estimate the effect of beam power on the sample...... temperature. For THz time domain systems, we indicate how to use our model as a worst-case approximation based on the beam average power. It turns out that THz pulses created from photoconductive antennas give a negligible increase in temperature. As biotissue contains a high water content, this leads...

  13. Mathematical models for Enterococcus faecalis recovery after microwave water disinfection.

    Science.gov (United States)

    Benjamin, Earl; Reznik, Aron; Benjamin, Ellis; Pramanik, Saroj K; Sowers, Louise; Williams, Arthur L

    2009-12-01

    Microwave water disinfection is a rapid purification technique which can give billions of people access to clean drinking water. However, better understanding of bacterial recovery after microwave heating over time is necessary to determine parameters such as delayed bacterial growth rates and maximum bacterial yields. Mathematical models for Enterococcus faecalis recovery after microwave treatment in optimum growth conditions were developed for times up to 5 minutes using an optical absorbance method. Microwave times below 3 minutes (2,450 MHz, 130W) showed that bacterial recovery maintained a time-dependent sigmoidal form which included a maximum value. At microwave times greater than three minutes, bacterial recovery, with a time-dependent exponential form, significantly decreased and did not reach the maximum value within the interval of observance (0-8 hours). No bacterial growth was found after 6 minutes of microwave treatment. The prepared mathematical models were produced by transforming the given variables to the logistic or exponential functions. We found that time-dependent maximum growth rates and lag times could be approximated with second order polynomial functions. The determined models can be used as a template to illustrate bacterial survival during water purification using microwave irradiation, in both commercial and industrial processes.

  14. A Conceptual Model for Water Sensitive City in Surabaya

    Science.gov (United States)

    Pamungkas, A.; Tucunan, K. P.; Navastara, A.; Idajati, H.; Pratomoatmojo, N. A.

    2017-08-01

    Frequent inundated areas, low quality of water supply, highly dependent water sources from external are some key problems in Surabaya water balance. Many aspects of urban development have stimulated those problems. To uncover the complexity of water balance in Surabaya, a conceptual model for water sensitive city is constructed to find the optimum solution. A system dynamic modeling is utilized to assist and enrich the idea of conceptual model. A secondary analysis to a wide range data directs the process in making a conceptual model. FGD involving many experts from multidiscipline are also used to finalize the conceptual model. Based on those methods, the model has four main sub models that are; flooding, land use change, water demand and water supply. The model consists of 35 key variables illustrating challenges in Surabaya urban water.

  15. Integrated modeling of ozonation for optimization of drinking water treatment

    NARCIS (Netherlands)

    van der Helm, A.W.C.

    2007-01-01

    Drinking water treatment plants automation becomes more sophisticated, more on-line monitoring systems become available and integration of modeling environments with control systems becomes easier. This gives possibilities for model-based optimization. In operation of drinking water treatment

  16. Determinants of cyanuric acid and melamine assembly in water.

    Science.gov (United States)

    Ma, Mingming; Bong, Dennis

    2011-07-19

    While the recognition of cyanuric acid (CA) by melamine (M) and their derivatives has been known to occur in both water and organic solvents for some time, analysis of CA/M assembly in water has not been reported (Ranganathan, A.; Pedireddi, V. R.; Rao, C. N. R. J. Am. Chem. Soc.1999, 121, 1752-1753; Mathias, J. P.; Simanek, E. E.; Seto, C. T.; Whitesides, G. M. Macromol. Symp.1994, 77, 157-166; Zerkowski, J. A.; MacDonald, J. C.; Seto, C. T.; Wierda, D. A.; Whitesides, G. M. J. Am. Chem. Soc.1994, 116, 2382-2391; Mathias, J. P.; Seto, C. T.; Whitesides, G. M. Polym. Prepr.1993, 34, 92-93; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1993, 115, 905-916; Zerkowski, J. A.; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1992, 114, 5473-5475; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1990, 112, 6409-6411; Wang, Y.; Wei, B.; Wang, Q. J. Chem. Cryst.1990, 20, 79-84; ten Cate, M. G. J.; Huskens, J.; Crego-Calama, M.; Reinhoudt, D. N. Chem.-Eur. J.2004, 10, 3632-3639). We have examined assembly of CA/M, as well as assembly of soluble trivalent CA and M derivatives (TCA/TM), in aqueous solvent, using a combination of solution phase NMR, isothermal titration and differential scanning calorimetry (ITC/DSC), cryo-transmission electron microscopy (cryo-TEM), and synthetic chemistry. While the parent heterocycles coprecipitate in water, the trivalent system displays more controlled and cooperative assembly that occurs at lower concentrations than the parent and yields a stable nanoparticle suspension. The assembly of both parent and trivalent systems is rigorously 1:1 and proceeds as an exothermic, proton-transfer coupled process in neutral pH water. Though CA and M are considered canonical hydrogen-bonding motifs in organic solvents, we find that their assembly in water is driven in large part by enthalpically favorable surface-area burial, similar to what is observed with nucleic acid recognition. There are currently few synthetic systems capable of robust molecular

  17. Determination of estrogenic potential in waste water without sample extraction.

    Science.gov (United States)

    Avberšek, Miha; Žegura, Bojana; Filipič, Metka; Uranjek-Ževart, Nataša; Heath, Ester

    2013-09-15

    This study describes the modification of the ER-Calux assay for testing water samples without sample extraction (NE-(ER-Calux) assay). The results are compared to those obtained with ER-Calux assay and a theoretical estrogenic potential obtained by GC-MSD. For spiked tap and waste water samples there was no statistical difference between estrogenic potentials obtained by the three methods. Application of NE-(ER-Calux) to "real" influent and effluents from municipal waste water treatment plants and receiving surface waters found that the NE-(ER-Calux) assay gave higher values compared to ER-Calux assay and GC-MSD. This is explained by the presence of water soluble endocrine agonists that are usually removed during extraction. Intraday dynamics of the estrogenic potential of a WWTP influent and effluent revealed an increase in the estrogenic potential of the influent from 12.9 ng(EEQ)/L in the morning to a peak value of 40.0 ng(EEQ)/L in the afternoon. The estrogenic potential of the effluent was

  18. Physical Modeling of Scaled Water Distribution System Networks.

    Energy Technology Data Exchange (ETDEWEB)

    O' Hern, Timothy J.; Hammond, Glenn Edward; Orear, Leslie ,; van Bloemen Waanders, Bart G.; Paul Molina; Ross Johnson

    2005-10-01

    Threats to water distribution systems include release of contaminants and Denial of Service (DoS) attacks. A better understanding, and validated computational models, of the flow in water distribution systems would enable determination of sensor placement in real water distribution networks, allow source identification, and guide mitigation/minimization efforts. Validation data are needed to evaluate numerical models of network operations. Some data can be acquired in real-world tests, but these are limited by 1) unknown demand, 2) lack of repeatability, 3) too many sources of uncertainty (demand, friction factors, etc.), and 4) expense. In addition, real-world tests have limited numbers of network access points. A scale-model water distribution system was fabricated, and validation data were acquired over a range of flow (demand) conditions. Standard operating variables included system layout, demand at various nodes in the system, and pressure drop across various pipe sections. In addition, the location of contaminant (salt or dye) introduction was varied. Measurements of pressure, flowrate, and concentration at a large number of points, and overall visualization of dye transport through the flow network were completed. Scale-up issues that that were incorporated in the experiment design include Reynolds number, pressure drop across nodes, and pipe friction and roughness. The scale was chosen to be 20:1, so the 10 inch main was modeled with a 0.5 inch pipe in the physical model. Controlled validation tracer tests were run to provide validation to flow and transport models, especially of the degree of mixing at pipe junctions. Results of the pipe mixing experiments showed large deviations from predicted behavior and these have a large impact on standard network operations models.3

  19. METHOD FOR NITRATE DETERMINATION IN WATER IN THE PRESENCE OF NITRITE

    Directory of Open Access Journals (Sweden)

    Maria Sandu

    2014-12-01

    Full Text Available The study relates to determination of nitrate in presence of nitrite in water and can be used in the quality monitoring of natural water (surface and groundwater, drinking water, water from fish farms and public aquaria where autonomous filters is used. The nature and quantity of reagents used have insignificant impact on natural waters and sewages. According to the investigation, the method includes the removal of nitrite from the solution/water with sulfaminic acid, the nitrate ion reduction to nitrite using a reducing mixture that contains Na2SO4 and zinc dust in ratio of 100:5 and determining the nitrite with the Griess reagent.

  20. Definition and experimental determination of a soil-water retention surface

    OpenAIRE

    Salager, Simon; El Youssoufi, Moulay Saïd; Saix, Christian

    2010-01-01

    International audience; This paper deals with the definition and determination methods of the soil-water retention surface (SWRS), which is the tool used to present the hydromechanical behaviour of soils to highlight both the effect of suction on the change in water and total volumes and the effect of deformation with respect to the water retention capability. An experimental method is introduced to determine the SWRS and applied to a clayey silty sand. The determination of this surface is ba...

  1. Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

    Directory of Open Access Journals (Sweden)

    G. Ganbavale

    2014-05-01

    Full Text Available This work presents experimental data of the temperature dependence of water activity in aqueous organic solutions relevant for tropospheric conditions (200–273 K. Water activity (aw at low temperatures (T is a crucial parameter for predicting homogeneous ice nucleation. We investigated temperature dependent water activities, ice freezing and melting temperatures of solutions, and vapour pressures of a selection of atmospherically relevant aqueous organic systems. To measure aw over a wide composition range and with a focus on low temperatures, we use various aw measurement techniques and instruments: a dew point water activity meter, an electrodynamic balance (EDB, differential scanning calorimetry (DSC, and a setup to measure the total gas phase pressure at equilibrium over aqueous solutions. Water activity measurements were performed for aqueous multicomponent and multifunctional organic mixtures containing the functional groups typically found in atmospheric organic aerosols, such as hydroxyl, carboxyl, ketone, ether, ester, and aromatic groups. The aqueous organic systems studied at several fixed compositions over a considerable temperature range differ significantly in their temperature dependence. Aqueous organic systems of 1,4-butanediol and methoxyacetic acid show a moderate decrease in aw with decreasing temperature. The aqueous M5 system (a multicomponent system containing five different dicarboxylic acids and aqueous 2-(2-ethoxyethoxyethanol solutions both show a strong increase of water activity with decreasing temperature at high solute concentrations for TTaw can be reversed at low temperatures and that linear extrapolations of high temperature data may lead to erroneous predictions. To avoid this, experimentally determined aw at low temperature are needed to improve thermodynamic models towards lower temperatures and for improved predictions of the ice nucleation ability of organic–water systems.

  2. Feasibility of using portable, noninvasive pipe flowmeters and time totalizers for determining water use

    Science.gov (United States)

    Arvin, D.V.

    1992-01-01

    The feasibilityty of using noninvasive flowmeters for determining water use was investigated by attempting, and at some sites repeating, instantaneous pipe-flow measurements at 45 water-withdrawal sites by use of four portable noninvasive pipe flowmeters. The flowmeters measure flow in pipes; this flow is related to water use. Because actual water use can differ from the total flow in the pipe, water use is not, in itself, measured by the flowmeters.

  3. A water quality model applied for the rivers into the Qinhuangdao coastal water in the Bohai Sea, China

    Institute of Scientific and Technical Information of China (English)

    顾杰; 胡成飞; 匡翠萍; 邵亥冰; 张甲波; 刘会欣

    2016-01-01

    The water quality of all rivers into the Qinhuangdao coastal water was below the grade V in 2013. In this study, an inte- grated MIKE 11 water quality model is applied to deal with the water environment in the rivers into the Qinhuangdao coastal water. The model is first calibrated with the field measured chemical oxygen demand (COD) concentrations. Then the transport of the COD in the rivers into the Qinhuangdao coastal water is computed based on the model in the water environmental monitoring process. Numerical results show that the COD concentration decreases dramatically in the estuaries, from which we can determine the positions of long-term monitoring stations to monitor the river pollutions into the coastal water. Furthermore, different scenarios about the inputs of the point sources and the non-point sources are simulated to discuss the model application in the water enviro- nmental control, and simplified formula are derived for assessing the water quality and the environmental management of rivers.

  4. The Determination of Anionic Surfactants in Natural and Waste Waters.

    Science.gov (United States)

    Crisp, P. T.; And Others

    1983-01-01

    Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

  5. Spectrophotometric determination of fluoride in drinking water using ...

    African Journals Online (AJOL)

    2011-03-14

    Mar 14, 2011 ... for 1.5 mg∙ℓ-1 fluoride for the method using chrome azurol B were ... in drinking water can give rise to a number of adverse effects ... reagents, due to their spectrophotometric properties described .... Possible structure for aluminium chrome azurol B 1:2 complex ..... zirconium-eriochrome cyanine R. Anal.

  6. The Determination of Anionic Surfactants in Natural and Waste Waters.

    Science.gov (United States)

    Crisp, P. T.; And Others

    1983-01-01

    Background information, procedures, and results of an experiment suitable for measuring subpart per million concentrations of anionic surfactants in natural waters and waste effluents are provided. The experiment required only a spectrophotometer or filter photometer and has been successfully performed by students in an undergraduate environmental…

  7. Determination of Perchlorate in Bottled Water from Italy

    Directory of Open Access Journals (Sweden)

    Patrizia Iannece

    2013-06-01

    Full Text Available Perchlorate is regarded as an emerging persistent inorganic contaminant. It is widely known that perchlorate is an endocrine disruptor as it competitively inhibits iodide transport in the thyroid gland. As drinking water is the major source of human exposure to perchlorate, its occurrence in commercially available bottled waters purchased in different regions of Italy was investigated. Perchlorate was measured using the rapid, sensitive, and selective LC-ESI-MS/MS (liquid chromatography-electrospray tandem mass spectrometry method by multiple reaction monitoring (MRM of the transition 98.8→82.8, which corresponds to the loss of one oxygen atom in the perchlorate ion (ClO4−→ClO3−. The chlorine isotope ratio (35Cl/37Cl was used as a confirmation tool. The limit of quantification (LOQ for this method was 5 ng/L, and the recovery ranged from 94% to 108%. Perchlorate was detected in 44 of the 62 drinking waters tested, with concentrations ranging from <5 to 75 ng/L. These values are similar in magnitude to those reported in drinking water from the USA and do not pose an immediate health concern.

  8. Determination of Phenols in Water Samples using a Supported ...

    African Journals Online (AJOL)

    NJD

    industries.1 Phenols are also used as part of the raw materials in the production of a large ... during wastewater treatment, since chlorine is added as a disinfectant. ... European Union have listed phenols as priority pollutants. The official ... biological fluids15 and organotin compounds in natural waters.16. 2. Experimental.

  9. determination of lead at nanogram level in water samples by ...

    African Journals Online (AJOL)

    Preferred Customer

    concentration of Pb(II) in the range of 0.04–1.8 μg/mL for the system with a low ... storage battery, drainage from lead ore mines, paints, munitions, and ... Water samples were immediately filtered through cellulose nitrate (0.45 μm pore size, 47.

  10. Determination of Triclosan and Ketoprofen in River Water and ...

    African Journals Online (AJOL)

    NICO

    The method was validated by spiking ultra-pure water and wastewater ... detected in human milk.5 Triclosan inhibits the enoyl-acyl carrier ... simple, sensitive, accurate, rapid and affordable for the simulta- .... to other solvents tested. This is in ...

  11. Evaluating Water Conservation and Reuse Policies Using a Dynamic Water Balance Model

    Science.gov (United States)

    Qaiser, Kamal; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R.

    2013-02-01

    A dynamic water balance model is created to examine the effects of different water conservation policies and recycled water use on water demand and supply in a region faced with water shortages and significant population growth, the Las Vegas Valley (LVV). The model, developed using system dynamics approach, includes an unusual component of the water system, return flow credits, where credits are accrued for returning treated wastewater to the water supply source. In LVV, Lake Mead serves as, both the drinking water source and the receiving body for treated wastewater. LVV has a consumptive use allocation from Lake Mead but return flow credits allow the water agency to pull out additional water equal to the amount returned as treated wastewater. This backdrop results in a scenario in which conservation may cause a decline in the available water supply. Current water use in LVV is 945 lpcd (250 gpcd), which the water agency aims to reduce to 752 lpcd (199 gpcd) by 2035, mainly through water conservation. Different conservation policies focused on indoor and outdoor water use, along with different population growth scenarios, are modeled for their effects on the water demand and supply. Major contribution of this study is in highlighting the importance of outdoor water conservation and the effectiveness of reducing population growth rate in addressing the future water shortages. The water agency target to decrease consumption, if met completely through outdoor conservation, coupled with lower population growth rate, can potentially satisfy the Valley's water demands through 2035.

  12. Shallow Water Propagation and Surface Reverberation Modeling

    Science.gov (United States)

    2014-07-29

    term goals were to 1. exploit measurements of breaking wave noise and photographic images of whitecaps to infer bubble cloud populations at the sea ...surface reverberation in wind-driven seas , an additional objective has been to study the role of sub-surface bubbles on the attenuation and scattering of...acoustic signals, including determining methods for quantifying bubble populations with video footage of the sea surface and developing models of

  13. Drinking Water Temperature Modelling in Domestic Systems

    NARCIS (Netherlands)

    Moerman, A.; Blokker, M.; Vreeburg, J.; Van der Hoek, J.P.

    2014-01-01

    Domestic water supply systems are the final stage of the transport process to deliver potable water to the customers’ tap. Under the influence of temperature, residence time and pipe materials the drinking water quality can change while the water passes the domestic drinking water system. According

  14. Modelling price determination in South Africa

    Directory of Open Access Journals (Sweden)

    E Moolman

    2015-07-01

    Full Text Available South Africa has been faced with high inflation rates since the early 1970s. Despite continued monetary discipline the inflation target has not yet been met, highlighting South Africa’s price-vulnerability as a small open emerging economy and raising questions about the efficiency of monetary policy. The objectives of this paper are: (i to analyse the influence of monetary policy on inflation in the small open emerging economy of South Africa, (ii to highlight the channels other than monetary policy through which inflation can be influenced (iii to analyse the influence of international prices and the exchange rate on inflation, (iv to determine the role of the labour market on inflation, especially through wage-push dynamics and (v to determine the role of demand-pull factors on inflation.

  15. Shallow Water Measurements Using a Single Green Laser Corrected by Building a Near Water Surface Penetration Model

    Directory of Open Access Journals (Sweden)

    Jianhu Zhao

    2017-04-01

    Full Text Available To reduce the size and cost of an integrated infrared (IR and green airborne LiDAR bathymetry (ALB system, and improve the accuracy of the green ALB system, this study proposes a method to accurately determine water surface and water bottom heights using a single green laser corrected by the near water surface penetration (NWSP model. The factors that influence the NWSP of green laser are likewise analyzed. In addition, an NWSP modeling method is proposed to determine the relationship between NWSP and the suspended sediment concentration (SSC of the surface layer, scanning angle of a laser beam and sensor height. The water surface and water bottom height models are deduced by considering NWSP and using only green laser based on the measurement principle of the IR laser and green laser, as well as employing the relationship between NWSP and the time delay of the surface return of the green laser. Lastly, these methods and models are applied to a practical ALB measurement. Standard deviations of 3.0, 5.3, and 1.3 cm are obtained by the NWSP, water-surface height, and water-bottom height models, respectively. Several beneficial conclusions and recommendations are drawn through the experiments and discussions.

  16. Exploration of Water Resource and Multiple Model for Water Resource Development in Karst Areas with the Preferred Plane Theory

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    According to the theory of preferred plane, preferred planes (faults) always control the distribution of bedrock fissure water and hold abundant groundwater. Thus, the exploration of fissure or karst water can be converted into searching for the watery preferred plane (WPP). In the paper, the characteristic of watery preferred planes is analyzed and a series of superior indices has been set up. It is introduced that WPPs are determined by the methods of geological analysis, superior index and complex geophysical analysis. Meanwhile, new multiple model for water resource development in the water-scarce areas of karst mountainous regions are advanced.

  17. A method for the determination of residual beta activity in drinking water samples

    Energy Technology Data Exchange (ETDEWEB)

    Idoeta, R. [Dpto. Ingenieria Nuclear y Mecanica de Fluidos, E. T. S. Ingenieria de Bilbao - Universidad del Pais Vasco (UPV/EHU), Alda. Urquijo s/n. 48013 Bilbao (Spain)], E-mail: raquel.idoeta@ehu.es; Herranz, M.; Abelairas, A.; Legarda, F. [Dpto. Ingenieria Nuclear y Mecanica de Fluidos, E. T. S. Ingenieria de Bilbao - Universidad del Pais Vasco (UPV/EHU), Alda. Urquijo s/n. 48013 Bilbao (Spain)

    2007-09-15

    The determination of residual beta activity in drinking water is usually needed in most monitoring programs. In this work a procedure for its determination is described and expressions for the calculations of detection limits and uncertainties are proposed.

  18. An improved ET control method to determine the water-saving potential for farmland in Baiyangdian Watershed, China

    Institute of Scientific and Technical Information of China (English)

    Aiping PANG; Chuihui LI; Tao SUN; Zhifeng YANG

    2013-01-01

    Resource-based water-saving potential has been recognized as the reduction of evapotranspiration and water loss of inefficient irrigation systems.In this paper,an improved evapotranspiration control model is applied to calculate resource-based water-saving potential,considering the influences of effective rainfall (uncontrolled evapotranspiration) and irrigated water (controlled evapotranspiration).Farmland in Baiyangdian Watershed,a highly productive area in northern China,is analyzed to determine the water-saving potential of irrigation processes.The water-saving potential was zero,163.90× 106m3,and 318.24 × 106m3 in wet,normal,and dry years,respectively,and was greater in years with less rainfall.Under the combined effect of rainfall,crop water consumption,and crop water requirements,the watersaving potential showed obvious temporal and spatial variations.July and August comprised almost 98.6% of the annual potential.In the northeast and southwest comer of the study area,potential approached zero.The potential was 1.53 times greater in the north-central than in the south-central area.The model can furnish the appropriate timing and region to water managers for implementing water-saving strategies.

  19. A numerical model for ground temperature determination

    Science.gov (United States)

    Jaszczur, M.; Polepszyc, I.; Biernacka, B.; Sapińska-Śliwa, A.

    2016-09-01

    The ground surface temperature and the temperature with respect to depth are one of the most important issues for geotechnical and environmental applications as well as for plants and other living organisms. In geothermal systems, temperature is directly related to the energy resources in the ground and it influences the efficiency of the ground source system. The ground temperature depends on a very large number of parameters, but it often needs to be evaluated with good accuracy. In the present work, models for the prediction of the ground temperature with a focus on the surface temperature at which all or selected important ground and environmental phenomena are taken into account have been analysed. It has been found that the simplest models and the most complex model may result in a similar temperature variation, yet at a very low depth and for specific cases only. A detailed analysis shows that taking into account different types of pavement or a greater depth requires more complex and advanced models.

  20. Modeling the Determinants of Internet Use

    Science.gov (United States)

    Chen, Y. L.

    2008-01-01

    The purpose of the study is to build a model that predicts the level of Internet use by teachers of English as a foreign language in the northern Taiwanese higher education institutions. It examines interactional relationships among variables associated with barriers and issues of technology application as a means of analyzing the extent and the…

  1. Sample Size Determination for Rasch Model Tests

    Science.gov (United States)

    Draxler, Clemens

    2010-01-01

    This paper is concerned with supplementing statistical tests for the Rasch model so that additionally to the probability of the error of the first kind (Type I probability) the probability of the error of the second kind (Type II probability) can be controlled at a predetermined level by basing the test on the appropriate number of observations.…

  2. Determining surface water and bed sediment quality of Lake Kopa

    Directory of Open Access Journals (Sweden)

    Nurgul Kazangapovaa

    2016-10-01

    Full Text Available In this research, the results of a hydro-chemical study of Lake Kopa in Kazakhstan are described, in the context of the regional geography and aggravating ecological problems of the lake. Besides analyzing the concentrations of all major ions, heavy-metal ions and other pollutants, their vertical and horizontal distribution were also assessed. Moreover, water pollution indices (WPI were calculated for individual ions, classes of pollutants, and total pollution, revealing serious overload of human- induced pollution within the lake’s ecosystem. Concentrations of major ions and WPI were monitored over 2009-2013 period, revealing a distinct seasonal pattern and a multi-year periodicity in respect to the measured parameters. In addition, studying ion exchange between lake water and bottom sediment showed complex non-equilibrium processes besides leaching out Ca2+ and its exchange for Na+.

  3. Certified reference material to water content determination in bioethanol fuel

    Directory of Open Access Journals (Sweden)

    Janaína M. Rodrigues

    2012-01-01

    Full Text Available Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This paper presents the results of these studies. The characterization, homogeneity, short-term stability and long-term stability uncertainty contributions values were 0.00500, 0.0166, 0.0355 and 0.0391 mg g-1, respectively. The certificated value for water content of bioethanol fuel was (3.65 ± 0.11 mg g-1. This CRM is the first and up to now the unique in the world.

  4. DETERMINATION OF ECONOMIC SIZES FOR RC CYLINDRICAL WATER STORAGE TANKS

    Directory of Open Access Journals (Sweden)

    Güneş KOZLUCA

    2007-03-01

    Full Text Available Water storage tanks are built in different shapes and sizes according to needs. Designs of water storage tanks with low costs are quite important for the national economy. Cylindrical and sphere tanks are the most economic types of tanks in terms of material cost. In this study several cylindrical tank designs are made. Then most economic tank radius – tank height ratio is searched by simply changing thickness, height and the radius of the tank considered. Storage capacity of these cylindrical tanks are all the same. All these reinforced tanks have cylindrical reinforced concrete walls fixed at the bottom and free top edge without roof. It is thought that tanks constructed with this optimal ratio will be beneficial.

  5. Laser spectroscopic methods as a means of determining water pollutants

    Science.gov (United States)

    Kubitz, Joerg; Uebel, Ulrieke; Anders, Angelika

    1995-09-01

    The suitability of laser-induced fluorescence spectroscopy was evaluated as a method for the in-situ detection of water contaminants. For example, lead thallium, cerium, benzene, pyrene, toluene, xylene, naphtalene, and anthracene were investigated. The absorption-, fluorescence-, and excitation-spectra of each contaminant were measured in distilled water, artificial seawater and natural seawater as the examination of pollution spectra, that has been described in literature so far, does not characterize the contaminants dissolution in water. The chosen polycyclic aromatic hydrocarbons (PAHs) and heavy metals were excited by means of a frequency doubled dye laser, the latter being pumped by an excimer laser or by a frequency tripled Nd:YAG laser. The laser emitted radiation in the range from 220 nm to 400 nm. The fluorescence signal was recorded in the 230 nm to 600 nm range. The detection limits were in the ppb-range for the PAHs and in the ppm to ppb range for the heavy metals. Computer- simulations were applied to analyze the spectra of pollutant mixtures. They displayed a superimposition of the individual spectra. Discrete components of a mixture could be distinguished using this method. Finally, the influence of dissolved organic matter was investigated.

  6. Determinants of drinking arsenic-contaminated tubewell water in Bangladesh.

    Science.gov (United States)

    Khan, M M H; Aklimunnessa, Khandoker; Kabir, M; Mori, Mitsuru

    2007-09-01

    Bangladesh has already experienced the biggest catastrophe in the world due to arsenic contamination of drinking water. This study investigates the association of drinking arsenic-contaminated water (DACW) with both personal and household characteristics of 9116 household respondents using the household data of the Bangladesh Demographic and Health Survey (BDHS) 2004. Here DACW means that arsenic level in the drinking water is greater than the permissible limit (50 microg/l) of Bangladesh. The overall rate of DACW was 7.9%. It was found to be significantly associated with education, currently working, and division of Bangladesh, either by cross tabulation or multivariate logistic regression analyses or both. Similarly, household characteristics -- namely television, bicycle, materials of the wall and floor, total family members, number of sleeping rooms, and availability of foods -- were significantly associated in bivariate analyses. Many household characteristics -- namely electricity, television, wall and floor materials, and number of sleeping rooms -- revealed significant association in the logistic regression analysis when adjusted for age, education and division. This study indicates that respondents from Chittagong division and lower socio-economic groups (indicated by household characteristics) are at significantly higher risk of DACW. These findings should be taken into account during the planning of future intervention activities in Bangladesh.

  7. Experimental determination of viscosity of water based magnetite nanofluid for application in heating and cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Toghraie, Davood; Alempour, Seyed Mohammadbagher [Department of Mechanical Engineering, Khomeinishahr Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Afrand, Masoud, E-mail: masoud.afrand@pmc.iaun.ac.ir [Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

    2016-11-01

    In this paper, experimental determination of dynamic viscosity of water based magnetite nanofluid (Fe{sub 3}O{sub 4}/water) was performed. The viscosity was measured in the temperature range of 20–55 °C for various samples with solid volume fractions of 0.1%, 0.2%, 0.4%, 1%, 2% and 3%. The results showed that the viscosity considerably decreases with increasing temperature. Moreover, the viscosity enhances with an increase in the solid volume fraction, remarkably. The calculated viscosity ratios showed that the maximum viscosity enhancement was 129.7%. Using experimental data, a new correlation has been proposed to predict the viscosity of magnetite nanofluid (Fe{sub 3}O{sub 4}/water). A comparison between the experimental results and the correlation outputs showed that the proposed model has a suitable accuracy. - Highlights: • Preparing Magnetite nanofluids with solid volume fractions up to 3%. • Measuring viscosity in temperature range of 20–55 °C using Brookfield Viscometer. • Maximum viscosity enhancement occurred at volume fraction of 3% and was 129.7%. • Proposing new correlation to predict the viscosity of Fe3O4/water nanofluid.

  8. A marginal revenue equilibrium model for spatial water allocation

    Institute of Scientific and Technical Information of China (English)

    王劲峰; 刘昌明; 王智勇; 于静洁

    2002-01-01

    The outside water is transported into the water-shorted area. It is allocated among many sub-areas that composed the water-shorted area, in order to maximize the total benefit from the input water for the areas. This paper presents a model for spatial water allocation based on the marginal revenue of water utilization, taking the six southern districts of Hebei Province as an example.

  9. Complex of computer models for cold stress evaluation in water

    OpenAIRE

    І. I. Ermakova; N. G. Ivanushkina; A. Yu. Nikolaenko; Yu. N. Solopchuk

    2015-01-01

    Introduction. Due to the high value of water thermal conductivity comparing to air, stay of man in cold water (water temperature lower than 25 sup>°C) is associated with high life and health hazard. One of the ways to evaluate survival time of human in water is usage of statistics data about survivors and water temperature organized as tables and curves. Another method to evaluate survival time and physiological state of man in water is computer modelling of human thermoregulatory system. ...

  10. Diffusive properties of water in Artemia cysts as determined from quasi-elastic neutron scattering spectra. [Artemia shrimp

    Energy Technology Data Exchange (ETDEWEB)

    Trantham, E.C.; Rorschach, H.E.; Clegg, J.S.; Hazlewood, C.F.; Nicklow, R.M.; Wakabayashi, N.

    1984-05-01

    Results have been obtained on the quasi-elastic spectra of neutrons scattered from pure water, 20% agarose gel (hydration four grams H/sub 2/O per gram of dry solid) and cysts of the brine shrimp Artemia for hydrations between 0.10 and 1.2 grams H/sub 2/O per gram of dry solids. The spectra were interpreted using a two-component model that included contributions from the covalently bonded protons and the hydration water, and a mobile water fraction. The mobile fraction was described by a jump-diffusion correlation function for the translation motion and a simple diffusive orientational correlation function. The results for the line widths ..gamma..(Q/sup 2/) for pure water were in good agreement with previous measurements. The agarose results were consistent with NMR measurements that show a slightly reduced translational diffusion for the mobile water fraction. The Artemia results show that the translational diffusion coefficient of the mobile water fraction was greatly reduced from that of pure water. The line width was determined mainly by the rotational motion, which was also substantially reduced from the pure water value as determined from dielectric relaxation studies. The translational and rotational diffusion parameters were consistent with the NMR measurements of diffusion and relaxation. Values for the hydration fraction and the mean square thermal displacement as determined from the Q-dependence of line areas were also obtained.

  11. Water-vortex stabilized electric arc: I. Numerical model

    Science.gov (United States)

    Jenista, Jirí

    1999-11-01

    A numerical model for an electric arc stabilized by a water vortex has been proposed. The two-dimensional axisymmetric model includes the discharge area between the cathode and the orifice of the arc chamber. The production of water plasma, i.e. the rate of evaporation of a water wall, is taken either from experiments or is determined numerically by fitting of the outlet plasma parameters to the experimental ones. The computer results concern thermal, fluid dynamic and electrical characteristics of such arcs for the currents 300, 400, 500 and 600 A. It is found, for example, that the role of thermal diffusion within the discharge increases with current. The power losses from the arc due to radial conduction and radiation represent around 50% of the input power. Rotation of the plasma column due to the induced tangential velocity component has negligible effect on the overall arc performance. The calculated velocities, pressure drops and electrical potentials are in good agreement with experiments carried out on the water plasma torch PAL-160 operating at our Institute.

  12. Modeling of Water balance in semiarid region of Mexico

    Science.gov (United States)

    González-Sosa, E.; Mastachi-Loza, C.; Medina-frutos, C.; Ramos-Salinas, N. M.

    2012-04-01

    Around the world water is becoming scarce, especially in the semiarid regions where there is a high inter-annual variability in the amount and distribution of the rainfall. Studies on this kind of environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The present study was carried out from October 2005 to October 2008 in three semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Amazcala and Cadereyta in the State of Queretaro. The work aim was to provide a better understanding of the hydrological processes that occur in the semiarid ecosystems, specifically through two objectives (1) to quantify and to model the rainfall interception process (EI) employing an adequate sampling strategy and an evaluation of the models developed by Rutter et al. (1975) and Gash (1979) in two shrubs species: huisache (Acacia farnesisna) and mesquite (Prosopis laevigata) both, in situ and ex situ and (2) to quantify and model the water balance in order to define the distribution of the water and energy balance components in El Carmen and Cadereyta. For this purpose, the SiSPAT (Simple Soil Plant Atamosphere Transfer) model was used based on a parametrisation of the soil, plants and atmosphere components. It was found that EI represented between 20% and 22% of the total rainfall (PG). Gash's model reproduced EI with satisfactory efficiency (E>0.6), wind's speed and maximum intensity have a local effect on EI. It was also found that, using SiSPAT, the water balance components were particularly sensitive to parameters associated with the soil and the leaf area index. The model results showed that during the studied period, the annual evapotranspiration in Cadereyta was less than PG (-10 and -5%) and above PG for El Carmen (10 y 30%). Runoff and percolation at 5m were null. Finally in both sites there was a simulated loss of water stored in the soil. This, was

  13. Modeling soil water content for vegetation modeling improvement

    Science.gov (United States)

    Cianfrani, Carmen; Buri, Aline; Zingg, Barbara; Vittoz, Pascal; Verrecchia, Eric; Guisan, Antoine

    2016-04-01

    Soil water content (SWC) is known to be important for plants as it affects the physiological processes regulating plant growth. Therefore, SWC controls plant distribution over the Earth surface, ranging from deserts and grassland to rain forests. Unfortunately, only a few data on SWC are available as its measurement is very time consuming and costly and needs specific laboratory tools. The scarcity of SWC measurements in geographic space makes it difficult to model and spatially project SWC over larger areas. In particular, it prevents its inclusion in plant species distribution model (SDMs) as predictor. The aims of this study were, first, to test a new methodology allowing problems of the scarcity of SWC measurements to be overpassed and second, to model and spatially project SWC in order to improve plant SDMs with the inclusion of SWC parameter. The study was developed in four steps. First, SWC was modeled by measuring it at 10 different pressures (expressed in pF and ranging from pF=0 to pF=4.2). The different pF represent different degrees of soil water availability for plants. An ensemble of bivariate models was built to overpass the problem of having only a few SWC measurements (n = 24) but several predictors to include in the model. Soil texture (clay, silt, sand), organic matter (OM), topographic variables (elevation, aspect, convexity), climatic variables (precipitation) and hydrological variables (river distance, NDWI) were used as predictors. Weighted ensemble models were built using only bivariate models with adjusted-R2 > 0.5 for each SWC at different pF. The second step consisted in running plant SDMs including modeled SWC jointly with the conventional topo-climatic variable used for plant SDMs. Third, SDMs were only run using the conventional topo-climatic variables. Finally, comparing the models obtained in the second and third steps allowed assessing the additional predictive power of SWC in plant SDMs. SWC ensemble models remained very good, with

  14. On inclusion of water resource management in Earth System models – Part 1: Problem definition and representation of water demand

    Directory of Open Access Journals (Sweden)

    A. Nazemi

    2014-07-01

    Full Text Available Human activities have caused various changes in the Earth System, and hence, the interconnections between humans and the Earth System should be recognized and reflected in models that simulate the Earth System processes. One key anthropogenic activity is water resource management that determines the dynamics of human–water interactions in time and space. There are various reasons to include water resource management in Earth System models. First, the extent of human water requirements is increasing rapidly at the global scale and it is crucial to analyze the possible imbalance between water demands and supply under various scenarios of climate change and across various temporal and spatial scales. Second, recent observations show that human–water interactions, manifested through water resource management, can substantially alter the terrestrial water cycle, affect land-atmospheric feedbacks and may further interact with climate and contribute to sea-level change. Here, we divide the water resource management into two interdependent elements, related to water demand as well as water supply and allocation. In this paper, we survey the current literature on how various water demands have been included in large-scale models, including Land Surface Schemes and Global Hydrological Models. The available algorithms are classified based on the type of demand, mode of simulation and underlying modeling assumptions. We discuss the pros and cons of available algorithms, address various sources of uncertainty and highlight limitations in current applications. We conclude that current capability of large-scale models in terms of representing human water demands is rather limited, particularly with respect to future projections and online simulations. We argue that current limitations in simulating various human demands and their impact on the Earth System are mainly due to the uncertainties in data support, demand algorithms and large-scale models. To

  15. Determining the Water Bootprint of the Army’s Supply Chain

    Science.gov (United States)

    2011-05-01

    bootprint of a product is the sum of the water footprints of all the process steps • Coca - Cola determined the water footprint of its 0.5 liter bottle of... Coca - Cola – – Product Packaging – Product Ingredients – Plant Operations • Study concluded that approximately 35 liters of water are used to produce

  16. Application of Water Evaluation and Planning Model for Integrated Water Resources Management: Case Study of Langat River Basin, Malaysia

    Science.gov (United States)

    Leong, W. K.; Lai, S. H.

    2017-06-01

    Due to the effects of climate change and the increasing demand on water, sustainable development in term of water resources management has become a major challenge. In this context, the application of simulation models is useful to duel with the uncertainty and complexity of water system by providing stakeholders with the best solution. This paper outlines an integrated management planning network is developed based on Water Evaluation and Planning (WEAP) to evaluate current and future water management system of Langat River Basin, Malaysia under various scenarios. The WEAP model is known as an integrated decision support system investigate major stresses on demand and supply in terms of water availability in catchment scale. In fact, WEAP is applicable to simulate complex systems including various sectors within a single catchment or transboundary river system. To construct the model, by taking account of the Langat catchment and the corresponding demand points, we defined the hydrological model into 10 sub-hydrological catchments and 17 demand points included the export of treated water to the major cities outside the catchment. The model is calibrated and verified by several quantitative statistics (coefficient of determination, R2; Nash-Sutcliffe efficiency, NSE and Percent bias, PBIAS). The trend of supply and demand in the catchment is evaluated under three scenarios to 2050, 1: Population growth rate, 2: Demand side management (DSM) and 3: Combination of DSM and reduce non-revenue water (NRW). Results show that by reducing NRW and proper DSM, unmet demand able to reduce significantly.

  17. Spectrophotometric determination of the acidity constants of calcon in water and mixed water–organic solvents

    Directory of Open Access Journals (Sweden)

    MOHAMMAD MAZLOUM-ARDAKANI

    2009-02-01

    Full Text Available The acid–base properties of calcon (1-(2-hydroxy-1-naphthylazo-2-naphthol-4-sulfonic acid in water and mixed water–organic solvents at 25 °C at an ionic strength of 0.10 M are studied by a multiwavelength spectrophotometric method. The organic solvents used were the amphiprotic (methanol, dipolar aprotic (dimethylsulfoxide, and low basic aprotic (acetonitrile. To evaluate the pH absorbance data, a resolution method based on the combination of soft- and hard-modeling was applied. The acidity constants of all related equilibria were estimated using the whole spectral fitting of the collected data to an established factor analysis model. The data analysis program Datan was applied for determination of the acidity constants. The corresponding pKa values were determined in water and mixed water–organic solvents. Linear relationship between the acidity constants and the mole fraction of the different sol-vents in the mixtures exist. The effect of solvent properties on acid–base behavior is discussed.

  18. Determination of Vinyl Chloride at ug/l. Level in Water by Gas Chromatography

    Science.gov (United States)

    Bellar, Thomas A.; And Others

    1976-01-01

    A quantitative method for the determination of vinyl chloride in water is presented. Vinyl chloride is transfered to the gas phase by bubbling inert gas through the water. After concentration on silica gel or Carbosieve-B, determination is by gas chromatography. Confirmation of vinyl chloride is by gas chromatography-mass spectrometry. (Author/BT)

  19. Modeling of residual chlorine in water distribution system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Water quality within water distribution system may vary with both location and time. Water quality models are used to predict the spatial and temporal variation of water quality throughout water system. A model of residual chlorine decay in water pipe has been developed,given the consumption of chlorine in reactions with chemicals in bulk water, bio-films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall. Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed. Model is used to predict the decay of residual chlorine in an actual distribution system. Good agreement between calculated and measured values was obtained.

  20. Algorithm for Determining the Effectiveness of Water Conservation Measures.

    Science.gov (United States)

    1984-03-01

    Turnovsky Bruner Grima Wong Ridge, R. Leone, Ginn 1978 Miami, FL cross-sectional -1.33 dept. stores -0.89 grocery stores -0.14 to -0.30...Division of Building Technology, November 1982. M 7-2 _ ’ 21. Bruner , J.M. An Analysis of Municipal Water Demand in the Phoenix Metropolitan Area...Washington, D.C., June 1966. 89. Linaweaver, F.P. Jr., John C. Geyer, and Jerome B. Wolff. "Summary Report on the Research Project." JAWWA, 59, No

  1. Determination of arsenic species in water, soils and plants

    Energy Technology Data Exchange (ETDEWEB)

    Mattusch, J.; Wennrich, R. [UFZ - Center for Environmental Research Leipzig / Halle, Department of Analytical Chemistry, Leipzig (Germany); Schmidt, A.C.; Reisser, W. [University of Leipzig, Institute of Botany, Leipzig (Germany)

    2000-01-01

    Ion chromatographic separation coupled with ICP-MS was used to determine arsenic species in plant and soil extracts. A scheme for growth, harvesting, sample pre-treatment and analysis was developed for the arsenic species to enable determination. Preliminary results obtained with ten herb plants grown on arsenic-contaminated soil compared to non-contaminated soil show a heterogeneous pattern of accumulation rate, metabolization and detoxification mechanisms in monocots and dicots. Arsenite appears to be the major component in plants with good growth. Organic arsenic species were even detected at very low concentrations (< 150 {mu}g kg{sup -1} (dry mass)). (orig.)

  2. Shallow water model for horizontal centrifugal casting

    Science.gov (United States)

    Boháček, J.; Kharicha, A.; Ludwig, A.; Wu, M.

    2012-07-01

    A numerical model was proposed to simulate the solidification process of an outer shell of work roll made by the horizontal centrifugal casting technique. Shallow water model was adopted to solve the 2D average flow dynamics of melt spreading and the average temperature distribution inside the centrifugal casting mould by considering the centrifugal force, Coriolis force, viscous force due to zero velocity on the mould wall, gravity, and energy transport by the flow. Additionally, a 1D sub-model was implemented to consider the heat transfer in the radial direction from the solidifying shell to the mould. The solidification front was tracked by fulfilling the Stefan condition. Radiative and convective heat losses were included from both, the free liquid surface and the outer wall of the mould. Several cases were simulated with the following assumed initial conditions: constant height of the liquid metal (10, 20, and 30 mm), uniform temperature of the free liquid surface (1755 K). The simulation results have shown that while the solidification front remained rather flat, the free surface was disturbed by waves. The amplitude of waves increased with the liquid height. Free surface waves diminished as the solidification proceeded.

  3. A Novel Statistical Model for Water Age Estimation in Water Distribution Networks

    Directory of Open Access Journals (Sweden)

    Wei-ping Cheng

    2015-01-01

    Full Text Available The water retention time in the water distribution network is an important indicator for water quality. The water age fluctuates with the system demand. The residual chlorine concentration varies with the water age. In general, the concentration of residual chlorine is linearly dependent on the water demand. A novel statistical model using monitoring data of residual chlorine to estimate the nodal water age in water distribution networks is put forward in the present paper. A simplified two-step procedure is proposed to solve this statistical model. It is verified by two virtual systems and a practical application to analyze the water distribution system of Hangzhou city, China. The results agree well with that from EPANET. The model provides a low-cost and reliable solution to evaluate the water retention time.

  4. Snowmelt runoff modeling: Limitations and potential for mitigating water disputes

    Science.gov (United States)

    Kult, Jonathan; Choi, Woonsup; Keuser, Anke

    2012-04-01

    SummaryConceptual snowmelt runoff models have proven useful for estimating discharge from remote mountain basins including those spanning the various ranges of the Himalaya. Such models can provide water resource managers with fairly accurate predictions of water availability for operational purposes (e.g. irrigation and hydropower). However, these models have limited ability to address characteristic components of water disputes such as diversions, storage and withholding. Contemporary disputes between India and Pakistan surrounding the snowmelt-derived water resources of the Upper Indus Basin highlight the need for improved water balance accounting methods. We present a research agenda focused on providing refined hydrological contributions to water dispute mitigation efforts.

  5. Modeling water balance distribution in a natural semiarid region of central Mexico using a SVAT model

    Science.gov (United States)

    Mastachi-Loza, C. A.; Braud, I.; Gonzalez-Sosa, E.; Centro de Investigaciones Del Agua de Querétaro

    2010-12-01

    Around the world water is becoming insufficient, especially in the semiarid regions where there is a high inter-annual variability in the amount and distribution of the rainfall. Studies on this kind of environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The study was carried out from October 2005 to October 2008 in two semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Cadereyta in Queretaro State. The work aim was to provide a better understanding of the hydrological processes that occur in semiarid ecosystems, quantifying and modeling the water balance in order to define the distribution of the water and energy balance components in El Carmen and Cadereyta. For this purpose, the SiSPAT (Simple Soil Plant Atmosphere Transfer) model was used based on a parameterization of the soil, plants and atmosphere components. It was found that, using SiSPAT, the water balance components were particularly sensitive to parameters associated with the soil and the leaf area index. The model results showed that during the studied period, the annual evapotranspiration in Cadereyta was less than PG (-10 and -5%) and above PG for El Carmen (10 y 30%). Runoff and percolation at 5m were null. Finally in both sites there was a simulated loss of water stored in the soil.

  6. Validation of a spatial–temporal soil water movement and plant water uptake model

    KAUST Repository

    HEPPELL, J.

    2014-06-01

    © 2014, (publisher). All rights reserved. Management and irrigation of plants increasingly relies on accurate mathematical models for the movement of water within unsaturated soils. Current models often use values for water content and soil parameters that are averaged over the soil profile. However, many applications require models to more accurately represent the soil–plant–atmosphere continuum, in particular, water movement and saturation within specific parts of the soil profile. In this paper a mathematical model for water uptake by a plant root system from unsaturated soil is presented. The model provides an estimate of the water content level within the soil at different depths, and the uptake of water by the root system. The model was validated using field data, which include hourly water content values at five different soil depths under a grass/herb cover over 1 year, to obtain a fully calibrated system for plant water uptake with respect to climate conditions. When compared quantitatively to a simple water balance model, the proposed model achieves a better fit to the experimental data due to its ability to vary water content with depth. To accurately model the water content in the soil profile, the soil water retention curve and saturated hydraulic conductivity needed to vary with depth.

  7. Determinants of willingness to pay for improved water supply services in rural Kazakhstan

    Science.gov (United States)

    Tussupova, Kamshat

    2017-04-01

    The UN Sustainable development goals declare to provide water, sanitation and hygiene for all. The supply of affordable and safe water is a global priority and there is thus a requirement for a safe drinking water management and management of excreta disposal and wastewater. The current paper assesses the determinants of consumers' willingness to connect and pay (WTP) for the piped water in rural Kazakhstan. The results show that local villagers use water from different sources and at least three quarters of the respondents are willing to connect and use water from the piped water supply. The general defined determinants for WTP should be carefully considered among the different water users. Perceived water quality is a variable that is relevant for all water users. Other variables such as perceived reliability and the time-spent to collect water from the source, in-household treatment of water, and income perception are also significant but differently correlated with the WTP among different water users. Although, piped water is considered to be a safe system if properly managed, still some water users are reluctant to pay for the system and are satisfied with their current water supply and sanitation services. In this case, a proper management for the drinking water and wastewater and safe management of the excreta disposal should be supplied. It is recommended to include local water userś opinion as regard the willingness to connect and pay for the piped water system. The findings are of particular importance for policy-makers, water managers, engineers, and public health specialists.

  8. Evolved star water maser cloud size determined by star size

    CERN Document Server

    Richards, A M S; Gray, M D; Lekht, E E; Mendoza-Torres, J E; Murakawa, K; Rudnitskij, G; Yates, J A

    2012-01-01

    Cool, evolved stars undergo copious mass loss but the details of how the matter is returned to the ISM are still under debate. We investigated the structure and evolution of the wind at 5 to 50 stellar radii from Asymptotic Giant Branch and Red Supergiant stars. 22-GHz water masers around seven evolved stars were imaged using MERLIN, at sub-AU resolution. Each source was observed at between 2 and 7 epochs (several stellar periods). We compared our results with long-term Pushchino single dish monitoring. The 22-GHz emission is located in ~spherical, thick, unevenly filled shells. The outflow velocity doubles between the inner and outer shell limits. Water maser clumps could be matched at successive epochs separated by <2 years for AGB stars, or at least 5 years for RSG. This is much shorter than the decades taken for the wind to cross the maser shell, and comparison with spectral monitoring shows that some features fade and reappear. In 5 sources, most of the matched features brighten or dim in concert from...

  9. Morphology of Rain Water Channeling in Systematically Varied Model Sandy Soils

    Science.gov (United States)

    Wei, Yuli; Cejas, Cesare M.; Barrois, Rémi; Dreyfus, Rémi; Durian, Douglas J.

    2014-10-01

    We visualize the formation of fingered flow in dry model sandy soils under different rain conditions using a quasi-2D experimental setup and systematically determine the impact of the soil grain diameter and surface wetting properties on the water channeling phenomenon. The model sandy soils we use are random closely packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates a shallow top layer of soil and creates a horizontal water wetting front that grows downward homogeneously until instabilities occur to form fingered flows. For hydrophobic sandy soils, in contrast, we observe that rain water ponds on the top of the soil surface until the hydraulic pressure is strong enough to overcome the capillary repellency of soil and create narrow water channels that penetrate the soil packing. Varying the raindrop impinging speed has little influence on water channel formation. However, varying the rain rate causes significant changes in the water infiltration depth, water channel width, and water channel separation. At a fixed rain condition, we combine the effects of the grain diameter and surface hydrophobicity into a single parameter and determine its influence on the water infiltration depth, water channel width, and water channel separation. We also demonstrate the efficiency of several soil water improvement methods that relate to the rain water channeling phenomenon, including prewetting sandy soils at different levels before rainfall, modifying soil surface flatness, and applying superabsorbent hydrogel particles as soil modifiers.

  10. Water Modeling of Optimizing Tundish Flow Field

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-gang; YAN Hui-cheng; LIU Liu; WANG Xin-hua

    2007-01-01

    In the water modeling experiments, three cases were considered, i.e. , a bare tundish, a tundish equipped with a turbulence inhibitor, and a rectangular tundish equipped with weirs (dams) and a turbulence inhibitor. Comparing the RTD curves, inclusion separation, and the result of the streamline experiment, it can be found that the tundish equipped with weirs (dams) and a turbulence inhibitor has a great effect on the flow field and the inclusion separation when compared with the sole use or no use of the turbulent inhibitor or weirs (dams). In addition, the enlargement of the distance between the weir and dam will result in a better effect when the tundish equipped with weirs (dam) and a turbulence inhibitor was used.

  11. Refined Modeling of Water Temperature and Salinity in Coastal Areas

    Institute of Scientific and Technical Information of China (English)

    SHEN Yongming; ZHENG Yonghong; QIU Dahong

    2000-01-01

    The prediction of water temperature and salinity in coastal areas is one of the essential tasks in water quality control and management. This paper takes a refined forecasting model of water temperature and salinity in coastal areas as a basic target. Based on the Navier-Stokes equation and k- turbulence model, taking the characteristics of coastal areas into account, a refined model for water temperatureand salinity in coastal areas has been developed to simulate the seasonal variations of water temperatureand salinity fields in the Hakata Bay, Japan. The model takes into account the effects of a variety ofhydrodynamic and meteorological factors on water temperature and salinity. It predicts daily fluctuations in water temperature and salinity at different depths throughout the year. The model has been calibrated well against the data set of historical water temperature and salinity observations in the Hakata Bay,Japan.

  12. DETERMINATION OF WATER CONTENT IN PYROLYTIC TARS USING COULOMETRIC KARL-FISHER TITRATION

    Directory of Open Access Journals (Sweden)

    Lenka Jílková

    2017-02-01

    Full Text Available The liquid organic fraction of pyrolytic tar has a high energy value which makes possible its utilization as an energy source. However, before utilization, it is crucial to remove water from the liquid fraction. The presence of water reduces the energy value of pyrolytic tars. Water separation from the organic tar fraction is a complex process, since an emulsion can be readily formed. Therefore, after phase separation, it is important to know the residual water content in the organic phase and whether it is necessary to further dry it. The results presented in this manuscript focus on a water determination in liquid products from coal and biomass pyrolysis by a coulometric Karl‑Fischer titration. The Coulometric Karl‑Fischer titration is often used for a water content determination in gaseous, liquid and solid samples. However, to date, this titration method has not been used for a water determination in tars. A new water determination method, which has been tested on different types of tar, has been developed. The Coulometric Karl‑Fischer titration is suitable for tar samples with a water content not greater than 5 wt. %. The obtained experimental results indicate that the new introduced method can be used with a very good repeatability for a water content determination in tars.

  13. Modeling rapid mass movements using the shallow water equations

    Directory of Open Access Journals (Sweden)

    S. Hergarten

    2014-11-01

    Full Text Available We propose a new method to model rapid mass movements on complex topography using the shallow water equations in Cartesian coordinates. These equations are the widely used standard approximation for the flow of water in rivers and shallow lakes, but the main prerequisite for their application – an almost horizontal fluid table – is in general not satisfied for avalanches and debris flows in steep terrain. Therefore, we have developed appropriate correction terms for large topographic gradients. In this study we present the mathematical formulation of these correction terms and their implementation in the open source flow solver GERRIS. This novel approach is evaluated by simulating avalanches on synthetic and finally natural topographies and the widely used Voellmy flow resistance law. The results are tested against analytical solutions and the commercial avalanche model RAMMS. The overall results are in excellent agreement with the reference system RAMMS, and the deviations between the different models are far below the uncertainties in the determination of the relevant fluid parameters and involved avalanche volumes in reality. As this code is freely available and open source, it can be easily extended by additional fluid models or source areas, making this model suitable for simulating several types of rapid mass movements. It therefore provides a valuable tool assisting regional scale natural hazard studies.

  14. Are sap flow measurements useful for determining water use of fruit orchards, when absolute values are important?

    CSIR Research Space (South Africa)

    Taylor, NJ

    2013-06-01

    Full Text Available The determination of accurate figures for orchard water use is critical for improved irrigation scheduling and for the issuing of water licenses. Under- or over estimations can have serious implications for production and water resources in water...

  15. Multiwavelength spectrophotometric determination of acidity constants of 1-(2-thiazolylazo)-2-naphthol in methanol-water mixtures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The acid-base properties of 1-(2-thiazolylazo)-2-naphthol (TAN) in mixtures of methanol-water at 25 ℃ and an ionic strength of 0.1 mol/L are studied by a multi-wavelength spectrophotometric method. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program was used for determination of acidity constants. The corresponding pKa values in methanol-water mixtures were determined. There is a linear relationship between acidity constants and the mole fraction of methanol in the solvent mixtures.

  16. Model studies of dense water overflows in the Faroese Channels

    Science.gov (United States)

    Cuthbertson, Alan; Davies, Peter; Stashchuk, Nataliya; Vlasenko, Vasiliy

    2014-01-01

    The overflow of dense water from the Nordic Seas through the Faroese Channel system was investigated through combined laboratory experiments and numerical simulations using the Massachusetts Institute of Technology General Circulation Model. In the experimental study, a scaled, topographic representation of the Faroe-Shetland Channel, Wyville-Thomson Basin and Ridge and Faroe Bank Channel seabed bathymetry was constructed and mounted in a rotating tank. A series of parametric experiments was conducted using dye-tracing and drogue-tracking techniques to investigate deep-water overflow pathways and circulation patterns within the modelled region. In addition, the structure of the outflowing dense bottom water was investigated through density profiling along three cross-channel transects located in the Wyville-Thomson Basin and the converging, up-sloping approach to the Faroe Bank Channel. Results from the dye-tracing studies demonstrate a range of parametric conditions under which dense water overflow across the Wyville-Thomson Ridge is shown to occur, as defined by the Burger number, a non-dimensional length ratio and a dimensionless dense water volume flux parameter specified at the Faroe-Shetland Channel inlet boundary. Drogue-tracking measurements reveal the complex nature of flow paths and circulations generated in the modelled topography, particularly the development of a large anti-cyclonic gyre in the Wyville-Thompson Basin and up-sloping approach to the Faroe Bank Channel, which diverts the dense water outflow from the Faroese shelf towards the Wyville-Thomson Ridge, potentially promoting dense water spillage across the ridge itself. The presence of this circulation is also indicated by associated undulations in density isopycnals across the Wyville-Thomson Basin. Numerical simulations of parametric test cases for the main outflow pathways and density structure in a similarly-scaled Faroese Channels model domain indicate excellent qualitative agreement with

  17. Asian water futures - Multi scenarios, models and criteria assessment -

    Science.gov (United States)

    Satoh, Yusuke; Burek, Peter; Wada, Yoshihide; Flrörke, Martina; Eisner, Stephanie; Hanasaki, Naota; Kahil, Taher; Tramberend, Sylvia; Fischer, Günther; Wiberg, David

    2016-04-01

    A better understanding of the current and future availability of water resources is essential for the implementation of the recently agreed Sustainable Development Goals (SDGs). Long-term/efficient strategies for coping with current and potential future water-related challenges are urgently required. Although Representative Concentration Pathways (RCPs) and Shared Socioeconomic Pathways (SSPs) were develop for the impact assessment of climate change, very few assessments have yet used the SSPs to assess water resources. Then the IIASA Water Futures and Solutions Initiative (WFaS), developed a set of water use scenarios consistent with RCPs and SSPs and applying the latest climate changes scenarios. Here this study focuses on results for Asian countries for the period 2010-2050. We present three conceivable future pathways of Asian water resources, determined by feasible combinations of two RCPs and three SSPs. Such a scenario approach provides valuable insights towards identifying appropriate strategies as gaps between a "scenario world" and reality. In addition, for the assessment of future water resources a multi-criteria analysis is applied. A classification system for countries and watershed that consists of two broad dimensions: (i) economic and institutional adaptive capacity, (ii) hydrological complexity. The latter is composed of several sub-indexes including total renewable water resources per capita, the ratio of water demand to renewable water resource, variability of runoff and dependency ratio to external. Furthermore, this analysis uses a multi-model approach to estimate runoff and discharge using 5 GCMs and 5 global hydrological models (GHMs). Three of these GHMs calculate water use based on a consistent set of scenarios in addition to water availability. As a result, we have projected hot spots of water scarcity in Asia and their spatial and temporal change. For example, in a scenario based on SSP2 and RCP6.0, by 2050, in total 2.1 billion people

  18. Determination of water absorption and water holding capacities of different soil mixtures with MINIDRAIN system to enhance the plant growth

    Science.gov (United States)

    Sudan Acharya, Madhu; Rauchecker, Markus; Wu, Wei

    2014-05-01

    Soil water holding capacity is the amount of water that a given soil can hold against the force of gravity. Soil texture and organic matter are the key components that determine soil water holding capacity. Soils with smaller particle sizes, such as silt and clay have larger surface area can hold more water compared to sand which has large particle sizes which results in smaller surface area. A study report showed that 1% increase in soil humus will result in a 4% increase in stored soil water (Morris, 2004) and 1 part humus holds 4 parts of water (Wheeler and Ward, 1998). Therefore, the more humus that can be added to the soil, the greater the water holding capacity of the soil. As the level of organic matter increases in a soil, the water holding capacity also increases due to the affinity of organic matter for water. The water holding capacity of the soil is determined by the amount of water held in the soil sample vs. the dry weight of the sample. MINIDRAIN is a patented system made of geo-fabric (fleece) or combination of geosynthetics and humus. MINIDRAIN and vegetation nets developed by the company ÖKO-TEX (Linz, Austria) will improve the distribution of water and air in the soils, increase the growth of vegetation and reduce the soil erosion. Depending on the physical configuration, there are four different combinations of MINIDRAIN systems developed by ÖKO-TEX. a) Geotextile (fleece) strips of different sizes (e.g. 5x10x250 mm) b) Net formed strips (drainage nets) of different sizes c) Multilayer geotextile mats with humus, seeds or compost of different sizes (e.g. 10x30x200 mm) d) Multilayer geotextile net formed mats with humus, seeds or compost This paper describes the experimental results of the water absorption and water holding capacity of different forms of MINIDRAIN under different soil mixes. In this experiment, potting soil, coarse sand and LECA (Light weight clay aggregates) balls are mixed with different proportion of MINIDRAIN systems and

  19. Application of Normal Distribution Model to Estimate Root Water Uptake Profile by an Isotopic Approach

    Science.gov (United States)

    Yamanaka, T.; Matsuo, D.; Hirota, M.

    2008-12-01

    To confirm usefulness of a diagnostic model for estimating root water uptake profile by an isotopic approach, isotopic measurements of plant xylem water, soil water and groundwater were conducted at seven Japanese red pine forest sites and then the model was applied to the measured results. The model assumes that depth profile of relative uptake rate can be approximated by the normal distribution function, and xylem water isotopic composition is computed from interpolated depth profile of isotopic composition of subsurface waters. The peak depth and distribution range of water uptake zone for a given species at a given site are inversely determined by direct search method (assuming depth interval of 5 cm up to 2 m) so as to minimize root mean square error throughout observation period. Estimated water uptake profiles showed that in six sites the uptake zone of Japanese red pine (Pinus densiflora) ranged from 5 to 60 cm depth, while it was changed to deeper depths in the other site where Quercus myrsinaefolia and Pleioblastus chino coexist. On the other hand, Populus sieboldi and Malus sieboldii take up water from depths deeper than those for Pinus densiflora within a community, although the two species are usually considered as shallow rooted plants. These results indicate water source partitioning under inter-species competition, and we conclude that the present model is capable of making clear the plant water use strategy. Estimated water uptake zone also provides useful information for improving/calibrating prognostic, physical models of root water uptake.

  20. Model analysis of the effects of atmospheric drivers on storage water use in Scots pine

    Directory of Open Access Journals (Sweden)

    H. Verbeeck

    2007-08-01

    Full Text Available Storage water use is an indirect consequence of the interplay between different meteorological drivers through their effect on water flow and water potential in trees. We studied these microclimatic drivers of storage water use in Scots pine (Pinus sylvestris L. growing in a temperate climate. The storage water use was modeled using the ANAFORE model, integrating a dynamic water flow and – storage model with a process-based transpiration model. The model was calibrated and validated with sap flow measurements for the growing season of 2000 (26 May–18 October.

    Because there was no severe soil drought during the study period, we were able to study atmospheric effects. Incoming radiation and vapour pressure deficit (VPD were the main atmospheric drivers of storage water use. The general trends of sap flow and storage water use are similar, and follow more or less the pattern of incoming radiation. Nevertheless, considerable differences in the day-to-day pattern of sap flow and storage water use were observed. VPD was determined to be one of the main drivers of these differences. During dry atmospheric conditions (high VPD storage water use was reduced. This reduction was higher than the reduction in measured sap flow. Our results suggest that the trees did not rely more on storage water during periods of atmospheric drought, without severe soil drought. The daily minimum tree water content was lower in periods of high VPD, but the reserves were not completely depleted after the first day of high VPD, due to refilling during the night.

    Nevertheless, the tree water content deficit was a third important factor influencing storage water use. When storage compartments were depleted beyond a threshold, storage water use was limited due to the low water potential in the storage compartments. The maximum relative contribution of storage water to daily transpiration was also constrained by an increasing tree water content

  1. What determines water-bridge lifetimes at the surface of DNA? Insight from systematic molecular dynamics analysis of water kinetics for various DNA sequences.

    Science.gov (United States)

    Yonetani, Yoshiteru; Kono, Hidetoshi

    2012-01-01

    The lifetime during which a water molecule resides at the surface of a biomolecule varies according to the hydration site. What determines this variety of lifetimes? Despite many previous studies, there is still no uniform picture quantitatively explaining this phenomenon. Here we calculate the lifetime for a particular hydration pattern in the DNA minor groove, the water bridge, for various DNA sequences to show that the water-bridge lifetime varies from 1 to ~300ps in a sequence-dependent manner. We find that it follows 1/k(V(step))P(m), where P(m) and V(step) are two crucial factors, namely the probability of forming a specific hydrogen bond in which more than one donor atom participates, and the structural fluctuation of DNA, respectively. This relationship provides a picture of the water kinetics with atomistic detail and shows that water dissociation occurs when a particular hydrogen-bonding pattern appears. The rate constant of water dissociation k can be described as a function of the structural fluctuations of DNA. This picture is consistent with the model of Laage and Hynes proposing that hydrogen-bond switching occurs when an unusual number of hydrogen bonds are formed. The two new factors suggested here are discussed in the context of the surface's geometry and electrostatic nature, which were previously proposed as the determinants of water lifetimes.

  2. Ground-based RGB imaging to determine the leaf water potential of potato plants

    Science.gov (United States)

    Zakaluk, Robert F.

    The determination of plant water status from leaf water potential (Psi L) data obtained by conventional methods is impractical for meeting real time irrigation monitoring requirements. This research, undertaken first, in a greenhouse and then in the field, examined the use of artificial neural network (ANN) modeling of RGB (red green blue) images, captured by a ground-based, five mega pixel digital camera, to predict the leaf water potential of potato (Solanum tuberosum L). The greenhouse study examined cv. Russet Burbank, while the field study examined cv. Sangre. The protocol was similar in both studies: (1) images were acquired over different soil nitrate (N) and volumetric water content levels, (2) images were radiometrically calibrated, (3) green foliage was classified and extracted from the images, and (4) image transformations, and vegetation indices were calculated and transformed using principal components analysis (PCA). The findings from both studies were similar: (1) the R and G bands were more important than the B image band in the classification of green leaf pigment, (2) soil N showed an inverse linear relationship against leaf reflectance in the G image band, (3) the ANN model input neuron weights with more separation between soil N and PsiL were more important than other input neurons in predicting PsiL, and (4) the measured and predicted PsiL validation datasets were normally distributed with equal variances and means that were not significantly different. Based on these research findings, the ground-based digital camera proved to be an adequate sensor for image acquisition and a practical tool for acquiring data for predicting the PsiL of potato plants. Keywords: nitrogen, IHS transformation, chromaticity transformation, principal components, vegetation indices, remote sensing, artificial neural network, digital camera.

  3. 基于于随机-确定模型的渠井结合灌区用水优化配置%Study on Optimized Redistribution of Water Resources in Well-canal Irrigated Area Based on Stochastic-determination Model

    Institute of Scientific and Technical Information of China (English)

    贺屹; 祝田多娃

    2011-01-01

    research results in practice, the Visual Modflow software is used as a platform, and a groundwater stochastic-determination model ( GSDM) is developed based on time-series model and radial basis function neural network model (RBF-ANN) to make an intensive analysis of water pattern on a basis of prediction model of groundwater regime for Jinghui Canal Irrigated Area. The results provide a useful and powerful basis for the sustainable development and utilization of groundwater and optimized redistribution of water resources in irrigated areas.%陕西省泾惠渠灌区是一个比较典型的渠井结合灌区.由于该灌区地下水的掠夺式开发利用,使得地下水位总体上呈下降趋势,造成许多环境地质问题.如何合理开发利用地下水,优化配置灌溉水资源,是该渠井结合灌区和谐发展的关键.该研究以Visual Modflow软件为平台,并基于时间序列模型和径向基函数神经网络模型(RBFANN),建立了灌区地下水随机-确定动态预测模型,在对灌区水资源供需平衡分析的基础上,通过模型模拟计算,对灌区水资源进行优化配置,为该灌区合理开发利用地下水和灌溉水资源提供依据.

  4. Determination of pentachlorophenol in water and aquifer sediments by high-performance liquid chromatography

    Science.gov (United States)

    Goerlitz, D.F.

    1981-01-01

    Methods for the determination of pentachlorophenol (PCP) in water and aquifer sediments are presented. Reverse-phase high-performance liquid chromotography employing ion suppression and gradient elution is used. PCP can be determined directly in water at a lower limit of detection Of 0.2 micrograms per liter. For extracts of sediment, PCP can be determined to a lower limit of 1.0 micrograms per kilogram.

  5. Fluorimetric determination of uranium in water; Determinacion fluorimetrica de uranio en aguas

    Energy Technology Data Exchange (ETDEWEB)

    Acosta L, E. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: eal@nuclear.inin.mx

    1992-02-15

    The fluorimetric method for the determination of microquantities of uranium in water is described. This method covers the determination of uranium in water in the interval from 0.2 to 50 ppm on 50 ml. of radioactive base sample. These limits can be variable if the volume of the aliquot one of the base sample is changed, as well as the volume of the used aliquot one for to the final determination of uranium. (Author)

  6. An Optimal Design Model for New Water Distribution Networks in ...

    African Journals Online (AJOL)

    An Optimal Design Model for New Water Distribution Networks in Kigali City. ... a Linear Programming Problem (LPP) which involves the design of a new network of water distribution considering the cost in the form of unit price ... Article Metrics.

  7. Modeling, Instrumentation, Automation, and Optimization of Water Resource Recovery Facilities.

    Science.gov (United States)

    Sweeney, Michael W; Kabouris, John C

    2016-10-01

    A review of the literature published in 2015 on topics relating to water resource recovery facilities (WRRF) in the areas of modeling, automation, measurement and sensors and optimization of wastewater treatment (or water resource reclamation) is presented.

  8. On the cluster composition of supercritical water combining molecular modeling and vibrational spectroscopic data.

    Science.gov (United States)

    Tassaing, T; Garrain, P A; Bégué, D; Baraille, I

    2010-07-21

    The present study is aimed at a detailed analysis of supercritical water structure based on the combination of experimental vibrational spectra as well as molecular modeling calculations of isolated water clusters. We propose an equilibrium cluster composition model where supercritical water is considered as an ideal mixture of small water clusters (n=1-3) at the chemical equilibrium and the vibrational spectra are expected to result from the superposition of the spectra of the individual clusters, Thus, it was possible to extract from the decomposition of the midinfrared spectra the evolution of the partition of clusters in supercritical water as a function of density. The cluster composition predicted by this model was found to be quantitatively consistent with the near infrared and Raman spectra of supercritical water analyzed using the same procedure. We emphasize that such methodology could be applied to determine the portion of cluster in water in a wider thermodynamic range as well as in more complex aqueous supercritical solutions.

  9. Total Body Water Determination: Have We To Adapt Its Determination To The Patient Clinical Status?

    Directory of Open Access Journals (Sweden)

    Almudena Pérez Torres

    2012-06-01

    Conclusion: There is a good concordance between both methods in the determination of the TBW. The Watson formula overestimates the TBW in patients with high %FM and underestimates in those with high FFM. In the clinical practice, it is necessary to adapt the determination of TBW to the patient situation.

  10. Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

    OpenAIRE

    Dietmar Gerteisen; Robert Alink

    2013-01-01

    In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent ...

  11. Determination of water in NIST reference material for mineral oils

    Science.gov (United States)

    Cedergren; Nordmark

    2000-07-15

    The accuracy of the reference concentrations of moisture in electrical insulating oil RM 8506 and lubricating oil RM 8507 (both of mineral type) and specified by the National Institute of Standards and Technology (NIST) as containing 39.7 and 76.8 ppm (w/w) water, respectively, has recently been the subject of debate in this journal. To shed some further light on this controversy, we report in this correspondence results for these oils obtained by two additional methods, one based on specially designed reagents for diaphragm-free Karl Fischer (KF) coulometry and the other based on the concept of stripping at elevated temperature/continuous KF coulometry. A positive interference effect was shown to take place for RM 8506 when the direct coulometric method was used. If the results are corrected for this, the values including six different procedures varied in the range 13.5-15.6 ppm (w/w). For RM 8507, all values were between 42.5 and 47.2 ppm (w/w), which means that the values recommended by NIST for both reference oils using volumetric titration are about twice as high as those obtained with the other techniques. A possible explanation for this discrepancy is presented.

  12. A simple method for determining water content in organic solvents based on cobalt(II) complexes

    Institute of Scientific and Technical Information of China (English)

    Lin Zhou; Xiao Hua Liu; Hai Xin Bai; Hong Juan Wang

    2011-01-01

    A method to determine water content in organic solvents was developed based on the color change of cobalt(II) nitrate in different solvents. The color-change mechanism and optimal conditions for determining the water content were investigated. The results showed that there was a good linear relationships between the absorbance of cobalt(II) complexes in organic solvents and water contents with y in 0.9989~0.9994. This method has the advantages of low cost, good reproducibility, good sensitivity, simple in operation, fast in detection, friendly to the environment and no limitation on linear range for determining water content. It was used to determine water in samples with a satisfactory recovery in 97.81%~101.24%.

  13. MoGIRE: A Model for Integrated Water Management

    Science.gov (United States)

    Reynaud, A.; Leenhardt, D.

    2008-12-01

    Climate change and growing water needs have resulted in many parts of the world in water scarcity problems that must by managed by public authorities. Hence, policy-makers are more and more often asked to define and to implement water allocation rules between competitive users. This requires to develop new tools aiming at designing those rules for various scenarios of context (climatic, agronomic, economic). If models have been developed for each type of water use however, very few integrated frameworks link these different uses, while such an integrated approach is a relevant stake for designing regional water and land policies. The lack of such integrated models can be explained by the difficulty of integrating models developed by very different disciplines and by the problem of scale change (collecting data on large area, arbitrate between the computational tractability of models and their level of aggregation). However, modelers are more and more asked to deal with large basin scales while analyzing some policy impacts at very high detailed levels. These contradicting objectives require to develop new modeling tools. The CALVIN economically-driven optimization model developed for managing water in California is a good example of this type of framework, Draper et al. (2003). Recent reviews of the literature on integrated water management at the basin level include Letcher et al. (2007) or Cai (2008). We present here an original framework for integrated water management at the river basin scale called MoGIRE ("Modèle pour la Gestion Intégrée de la Ressource en Eau"). It is intended to optimize water use at the river basin level and to evaluate scenarios (agronomic, climatic or economic) for a better planning of agricultural and non-agricultural water use. MoGIRE includes a nodal representation of the water network. Agricultural, urban and environmental water uses are also represented using mathematical programming and econometric approaches. The model then

  14. Model predictive control on open water systems

    NARCIS (Netherlands)

    Van Overloop, P.J.

    2006-01-01

    Human life depends on water daily, especially for drinking and food production. Also, human life needs to be protected against excess of water caused by heavy precipitation and floods. People have formed water management organizations to guarantee these necessities of life for communities. These org

  15. A model for optimisation of water management in rice polders in Thailand

    NARCIS (Netherlands)

    Wandee, P.; Schultz, E.; Tingsanchali, T.

    2005-01-01

    This paper presents a mathematical model for the determination of optimal values for the main components of water management systems in rice polders in Thailand. The aim of the water management system in a rice area is to create good growing conditions for the crops. Under the hydrological

  16. Determination of Trichloroethylene in Water by Liquid–Liquid Microextraction Assisted Solid Phase Microextraction

    Directory of Open Access Journals (Sweden)

    Mengliang Zhang

    2015-02-01

    Full Text Available A method for the determination of trichloroethylene (TCE in water using portable gas chromatography/mass spectrometry (GC/MS was developed. A novel sample preparation method, liquid–liquid microextraction assisted solid phase microextraction (LLME–SPME, is introduced. In this method, 20 µL of hexane was added to 10 mL of TCE contaminated aqueous samples to assist headspace SPME. The extraction efficiency of SPME was significantly improved with the addition of minute amounts of organic solvents (i.e., 20 µL hexane. The absolute recoveries of TCE at different concentrations were increased from 11%–17% for the samples extracted by SPME to 29%–41% for the samples extracted by LLME–SPME. The method was demonstrated to be linear from 10 to 1000 ng mL−1 for TCE in water. The improvements on extraction efficiencies were also observed for toluene and 1, 2, 4-trichlorobenzene in water by using LLME–SPME method. The LLME–SPME method was optimized by using response surface modeling (RSM.

  17. Modeling the influence of temperature, water activity and water mobility on the persistence of Salmonella in low-moisture foods.

    Science.gov (United States)

    Farakos, S M Santillana; Frank, J F; Schaffner, D W

    2013-09-02

    Salmonella can survive in low-moisture foods for long periods of time. Reduced microbial inactivation during heating is believed to be due to the interaction of cells and water, and is thought to be related to water activity (a(w)). Little is known about the role of water mobility in influencing the survival of Salmonella in low-moisture foods. The aim of this study was to determine how the physical state of water in low-moisture foods influences the survival of Salmonella and to use this information to develop mathematical models that predict the behavior of Salmonella in these foods. Whey protein powder of differing water mobilities was produced by pH adjustment and heat denaturation, and then equilibrated to aw levels between 0.19±0.03 and 0.54±0.02. Water mobility was determined by wide-line proton-NMR. Powders were inoculated with a four-strain cocktail of Salmonella, vacuum-sealed and stored at 21, 36, 50, 60, 70 and 80°C. Survival data was fitted to the log-linear, the Geeraerd-tail, the Weibull, the biphasic-linear and the Baranyi models. The model with the best ability to describe the data over all temperatures, water activities and water mobilities (f(test)water mobility on the survival of Salmonella was evaluated using multiple linear regression. Secondary models were developed and then validated in dry non-fat dairy and grain, and low-fat peanut and cocoa products within the range of the modeled data. Water activity significantly influenced the survival of Salmonella at all temperatures, survival increasing with decreasing a(w). Water mobility did not significantly influence survival independent of a(w). Secondary models were useful in predicting the survival of Salmonella in various low-moisture foods providing a correlation of R=0.94 and an acceptable prediction performance of 81%. The % bias and % discrepancy results showed that the models were more accurate in predicting survival in non-fat food systems as compared to foods containing low

  18. Parameterization of small intestinal water volume using PBPK modeling.

    Science.gov (United States)

    Maharaj, Anil; Fotaki, Nikoletta; Edginton, Andrea

    2015-01-25

    To facilitate accurate predictions of oral drug disposition, mechanistic absorption models require optimal parameterization. Furthermore, parameters should maintain a biological basis to establish confidence in model predictions. This study will serve to calculate an optimal parameter value for small intestinal water volume (SIWV) using a model-based approach. To evaluate physiologic fidelity, derived volume estimates will be compared to experimentally-based SIWV determinations. A compartmental absorption and transit (CAT) model, created in Matlab-Simulink®, was integrated with a whole-body PBPK model, developed in PK-SIM 5.2®, to provide predictions of systemic drug disposition. SIWV within the CAT model was varied between 52.5mL and 420mL. Simulations incorporating specific SIWV values were compared to pharmacokinetic data from compounds exhibiting solubility induced non-proportional changes in absorption using absolute average fold-error. Correspondingly, data pertaining to oral administration of acyclovir and chlorothiazide were utilized to derive estimates of SIWV. At 400mg, a SIWV of 116mL provided the best estimates of acyclovir plasma concentrations. A similar SIWV was found to best depict the urinary excretion pattern of chlorothiazide at a dose of 100mg. In comparison, experimentally-based estimates of SIWV within adults denote a central tendency between 86 and 167mL. The derived SIWV (116mL) represents the optimal parameter value within the context of the developed CAT model. This result demonstrates the biological basis of the widely utilized CAT model as in vivo SIWV determinations correspond with model-based estimates.

  19. Using System Dynamic Model and Neural Network Model to Analyse Water Scarcity in Sudan

    Science.gov (United States)

    Li, Y.; Tang, C.; Xu, L.; Ye, S.

    2017-07-01

    Many parts of the world are facing the problem of Water Scarcity. Analysing Water Scarcity quantitatively is an important step to solve the problem. Water scarcity in a region is gauged by WSI (water scarcity index), which incorporate water supply and water demand. To get the WSI, Neural Network Model and SDM (System Dynamic Model) that depict how environmental and social factors affect water supply and demand are developed to depict how environmental and social factors affect water supply and demand. The uneven distribution of water resource and water demand across a region leads to an uneven distribution of WSI within this region. To predict WSI for the future, logistic model, Grey Prediction, and statistics are applied in predicting variables. Sudan suffers from severe water scarcity problem with WSI of 1 in 2014, water resource unevenly distributed. According to the result of modified model, after the intervention, Sudan’s water situation will become better.

  20. Uncertainties in using remote sensing for water use determination: a case study in a heterogeneous study area in South Africa

    Directory of Open Access Journals (Sweden)

    L. A. Gibson

    2010-09-01

    Full Text Available South Africa is a water scarce country where it is important for water managers to have accurate information on water resource occurrence and use. A remote sensing project highlighted many uncertainties in using complex remote sensing models to determine water use in a heterogeneous study area. The severity of the uncertainties was confirmed as the results across the catchment showed a higher total evapotranspiration than precipitation. This paper illustrates some of the uncertainties and limitations using the evapotranspiration component of the water balance as calculated by the Surface Energy Balance System (SEBS model, as an example.

    The introduction of uncertainties in the derivation of evapotranspiration were identified as: (1 sensitivity to land surface and air temperature gradient; (2 the choice of fractional vegetation cover formula; (3 height of wind speed measurement in relation to displacement height indicating a maximum canopy height at which the SEBS model should be used; and (4 study area heterogeneity.

    Uncertainties and errors are compounded when considering that the SEBS model is a complex model, requiring several image processing sequences that are combined to produce the final result. It was shown how the production and propagation of errors in the SEBS model can contribute to uncertainties in flux estimation and ultimately to uncertainties in the estimation of actual evapotranspiration.

  1. Determination of the crystal growth mechanism of KCl in ethanol?water system

    Science.gov (United States)

    Liszi, I.; Hasznosné-Nezdei, M.; Lakatos, B. G.; Sapundzhiev, Ts. J.; Popov, R. G.

    1999-03-01

    The mechanism of crystal growth of KCl in ethanol-water system is studied by Nielsen's map-model, and the growth rate is estimated by the induction time (nucleation rate, growth rate) function in a salting-out crystallization system. In the experiments, the induction time and the particle size distribution of the final product were measured, and the solid-liquid interfacial tension was calculated from the induction period data. The map of rate control of crystal-growth for the KCl-ethanol-water salting out system was constructed by taking into consideration that the liquid-vapour interfacial tension varied with the variation of the ethanol concentration, and, as a consequence, the solid-liquid interfacial tension varied as well. As a result, diffusion controlled crystal growth was obtained as a rate-determining step for supersaturation ratios 0.01<0.45. For determining the crystal growth rate, the nucleation rate was estimated from the experimental average particle number and induction period, applying the assumption that all nuclei were born during the induction period. The results, obtained by using linear and non-linear regressions, have appeared to be in good agreement with the data published in the literature.

  2. Numerical determination of vertical water flux based on soil temperature profiles

    Science.gov (United States)

    Tabbagh, Alain; Cheviron, Bruno; Henine, Hocine; Guérin, Roger; Bechkit, Mohamed-Amine

    2017-07-01

    High sensitivity temperature sensors (0.001 K sensitivity Pt100 thermistors), positioned at intervals of a few centimetres along a vertical soil profile, allow temperature measurements to be made which are sensitive to water flux through the soil. The development of high data storage capabilities now makes it possible to carry out in situ temperature recordings over long periods of time. By directly applying numerical models of convective and conductive heat transfer to experimental data recorded as a function of depth and time, it is possible to calculate Darcy's velocity from the convection transfer term, thus allowing water infiltration/exfiltration through the soil to be determined as a function of time between fixed depths. In the present study we consider temperature data recorded at the Boissy-le-Châtel (Seine et Marne, France) experimental station between April 16th, 2009 and March 8th, 2010, at six different depths and 10-min time intervals. We make use of two numerical finite element models to solve the conduction/convection heat transfer equation and compare their merits. These two models allow us to calculate the corresponding convective flux rate every day using a group of three sensors. The comparison of the two series of calculated values centred at 24 cm shows reliable results for periods longer than 8 days. These results are transformed in infiltration/exfiltration value after determining the soil volumetric heat capacity. The comparison with the rainfall and evaporation data for periods of ten days shows a close accordance with the behaviour of the system governed by rainfall evaporation rate during winter and spring.

  3. Soil erosion by water - model concepts and application

    Science.gov (United States)

    Schmidt, Juergen

    2010-05-01

    Soil erosion is not a continuous process but the result of isolated surface runoff events, whose erosional effects are determined by numerous temporally and spatially varying variables. Thus the monitoring of soil loss by direct observation is extremely limited with respect to space and time. Usually observation plots cover an area of less than 100 m2 and the observation period is less than 10 years. In order to estimate soil losses by water erosion for others than empirically observable conditions, mathematical models are needed, which are able to describe the interaction of the different physical mechanisms involved either statistically or on the basis of physical algorithms. Such models are absolutely essential for risk prognoses on catchment and regional scale. Besides the aspect of soil conservation the delivery of sediments and sediment bound pollutants into surface water bodies are of increasing relevance in this context. Based on an exemplary selection of existing water erosion models this contribution aims to give an overview over different mathematical approaches used for the description of particle detachment, transport and deposition of soil particles. According to the chronology in the development of soil erosion models empirical algorithms will be presented first based on the USLE approach. However, since purely empirical models like USLE are limited to the estimation of annual soil loss further attempts in soil erosion modelling are focussed on event based estimations considering the fact that soil erosion is not a continuous process but the result of isolated runoff events. One of the first models of this type was CREAMS using physically based algorithms in combination with empirical ones in order to describe the basic erosion processes. Today there are diverse soil erosion models available following in principle the CREAMS concept but using different algorithms in detail. Concerning particle detachment, transport and deposition alternative

  4. Kinetic model of water vapour adsorption by gluten-free starch

    Science.gov (United States)

    Ocieczek, Aneta; Kostek, Robert; Ruszkowska, Millena

    2015-01-01

    This study evaluated the kinetics of water vapour adsorption on the surface of starch molecules derived from wheat. The aim of the study was to determine an equation that would allow estimation of water content in tested material in any timepoint of the adsorption process aimed at settling a balance with the environment. An adsorption isotherm of water vapour on starch granules was drawn. The parameters of the Guggenheim, Anderson, and De Boer equation were determined by characterizing the tested product and adsorption process. The equation of kinetics of water vapour adsorption on the surface of starch was determined based on the Guggenheim, Anderson, and De Boer model describing the state of equilibrium and on the model of a first-order linear inert element describing the changes in water content over time.

  5. Determination of fractionation of oxygen isotopes between rice grain and environmental water

    Science.gov (United States)

    Kaushal, R.; Ghosh, P.

    2013-12-01

    Oxygen isotopic composition (δ18O) of plant organic matter (POM) serves as a valuable proxy for paleoclimatic studies [1].The δ18O of POM emulates the isotopic composition of the source water [2]. Rice crop cultivation goes back to 12,000 years, when rice was first domesticated in China and the earliest cultivation of rice observed in India was during 3000- 2500 BC. Presently rice is cultivated in many countries around the world including India where the prerequisite of saturated soil water condition for optimum growth of rice crop is provided by the South west monsoons. Earlier studies on δ18O of rice have been limited to its geographic characterization [3]. However, detailed investigations to determine fractionation of oxygen isotopes in water, in different parts of a rice plant, with rice seed organic matter is the primary objective of this work. This is important for understanding the mechanism responsible for the transfer of source water signature to the seed organics and can facilitate understanding of past monsoonal regime using well preserved rice grain remains from archaeological sites. Water from the leaves and culms was extracted by means of heating and cryogenic distillation in a vacuum extraction system [4]. The source water and the water extracted from plant parts were analysed by CO2 equilibration method using Gas Bench peripheral. Rice seed powder, after removal of husk, is composed primarily of starch and were analysed using High Temperature Conversion-Elemental Analyser. Both these peripherals were coupled to an Isotope Ratio Mass spectrometer- MAT253 (Thermo Finnigan). Experimental results discussed here were based on greenhouse and field based studies of water and seed organic composition. The water fed to the plant in the green house showed an average δ18O value of -0.50‰ whereas the field water from irrigation covering the time of grain filling ranges between -1.03‰ and -3.08‰. Figure 1 displays the extent of enrichment recorded in

  6. Analysis Model for Domestic Hot Water Distribution Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.; Krarti, M.; Fang, X.

    2011-11-01

    A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.

  7. Modelling Soil Water Retention for Weed Seed Germination Sensitivity to Water Potential

    Directory of Open Access Journals (Sweden)

    W. John Bullied

    2012-01-01

    Full Text Available Soil water retention is important for the study of water availability to germinating weed seeds. Six soil water retention models (Campbell, Brooks-Corey, four- and five-parameter van Genuchten, Tani, and Russo with residual soil water parameter derivations were evaluated to describe water retention for weed seed germination at minimum threshold soil water potential for three hillslope positions. The Campbell, Brooks-Corey, and four-parameter van Genuchten model with modified or estimated forms of the residual parameter had superior but similar data fit. The Campbell model underestimated water retention at a potential less than −0.5 MPa for the upper hillslope that could result in underestimating seed germination. The Tani and Russo models overestimated water retention at a potential less than −0.1 MPa for all hillslope positions. Model selection and residual parameter specification are important for weed seed germination by representing water retention at the level of minimum threshold water potential for germination. Weed seed germination models driven by the hydrothermal soil environment rely on the best-fitting soil water retention model to produce dynamic predictions of seed germination.

  8. Measuring and Modeling the Displacement of Connate Water in Chalk Core Plugs during Water Injection

    DEFF Research Database (Denmark)

    Korsbech, Uffe C C; Aage, Helle Karina; Andersen, Bertel Lohmann;

    2006-01-01

    The movement of connate water spiked with gamma emitting 22Na was studied during laboratory water flooding of oil saturated chalk from a North Sea oil reservoir. Using a one dimensional gamma monitoring technique is was observed that connate water is piled-up at the front of the injection water...... and forms a mixed water bank with almost 100% connate water in the front behind which a gradual transition to pure injection water occurs. This result underpins log interpretations from waterflooded chalk reservoirs. An ad hoc model was set up by use of the results, and the process was examined...

  9. Using reactive artificial muscles to determine water exchange during reactions

    Science.gov (United States)

    Otero, T. F.; Martínez, J. G.; Zaifoglu, B.

    2013-10-01

    Artificial muscles based on films of conducting polymers translate film volume variations, driven by electrochemical reactions (Faradaic motors), into macroscopic movements with generation of mechanical energy. The reaction promotes exchange of counterions (anions here) and solvent molecules with the electrolyte. Attributing here both the film volume variation and the movement originated by these exchanges of ions and solvent, the described angles can be used to quantify the exchanged solvent. Different angles described by bending muscles consuming equal driving charges in electrolytes having the same cation and different anions were measured. The number of exchanged counterions is given by the consumed charge and the ion valence: this is a Faradaic reaction. The described angle fraction due to the exchanged anions is given by the number of anions and the crystallographic radius. Taking as reference the anion giving the shorter angle, whatever the consumed charge, the relative number of solvent molecules exchanged by the polymeric membrane during a reversible reaction was determined. Actuators and artificial muscles can be used as useful tools for, at least, an initial study of the solvent exchange during reactions in reactive gels.

  10. Ultrasensitive 4-methylumbelliferone fluorimetric determination of water contents in aprotic solvents.

    Science.gov (United States)

    Kłucińska, Katarzyna; Jurczakowski, Rafał; Maksymiuk, Krzysztof; Michalska, Agata

    2015-01-01

    A novel approach to the quantification of relatively small amounts of water present in low polarity, aprotic solvents is proposed. This method takes advantage of protolitic reaction of 4-methylumbelliferone dissolved in the solvent with water, acting as a base. The low emission intensity neutral 4-methylumbelliferone is transformed in reaction with water to a highly fluorescent anionic form. Thus the increase in emission intensity is observed for increasing water contents in aprotic solvents. For low water contents and highly lipophilic solvents, this method yields (in practical conditions) higher sensitivity compared to biamperometric Karl Fischer titration method in volumetric mode. It is also shown that organic compounds of protolitic character (amines, acids) not only interfere with water contents determination but increase the sensitivity of emission vs. water contents dependence. Introduction of aqueous solution of strong acid or base (HCl or NaOH) has similar effect on the system as introduction of pure water.

  11. Determination of moisture content and water activity in algae and fish by thermoanalytical techniques

    Directory of Open Access Journals (Sweden)

    Vilma Mota da Silva

    2008-01-01

    Full Text Available The water content in seafoods is very important since it affects their sensorial quality, microbiological stability, physical characteristics and shelf life. In this study, thermoanalytical techniques were employed to develop a simple and accurate method to determine water content (moisture by thermogravimetry (TG and water activity from moisture content values and freezing point depression using differential scanning calorimetry (DSC. The precision of the results suggests that TG is a suitable technique to determine moisture content in biological samples. The average water content values for fish samples of Lutjanus synagris and Ocyurus chrysurus species were 76.4 ± 5.7% and 63.3 ± 3.9%, respectively, while that of Ulva lactuca marine algae species was 76.0 ± 4.4%. The method presented here was also successfully applied to determine water activity in two species of fish and six species of marine algae collected in the Atlantic coastal waters of Bahia, in Brazil. Water activity determined in fish samples ranged from 0.946 - 0.960 and was consistent with values reported in the literature, i.e., 0.9 - 1.0. The water activity values determined in marine algae samples lay within the interval of 0.974 - 0.979.

  12. Determination of moisture content and water activity in algae and fish by thermoanalytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Vilma Mota da; Silva, Luciana Almeida; Andrade, Jailson B. de [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica]. E-mail: jailsong@ufba.br; Veloso, Marcia C. da Cunha [Centro Federal de Educacao Tecnologica da Bahia (CEFET-BA), Salvador, BA (Brazil)); Santos, Gislaine Vieira [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Biologia

    2008-07-01

    The water content in seafoods is very important since it affects their sensorial quality, microbiological stability, physical characteristics and shelf life. In this study, thermoanalytical techniques were employed to develop a simple and accurate method to determine water content (moisture) by thermogravimetry (TG) and water activity from moisture content values and freezing point depression using differential scanning calorimetry (DSC). The precision of the results suggests that TG is a suitable technique to determine moisture content in biological samples. The average water content values for fish samples of Lutjanus synagris and Ocyurus chrysurus species were 76.4 {+-} 5.7% and 63.3 {+-} 3.9%, respectively, while that of Ulva lactuca marine algae species was 76.0 {+-} 4.4%. The method presented here was also successfully applied to determine water activity in two species of fish and six species of marine algae collected in the Atlantic coastal waters of Bahia, in Brazil. Water activity determined in fish samples ranged from 0.946 - 0.960 and was consistent with values reported in the literature, i.e., 0.9 - 1.0. The water activity values determined in marine algae samples lay within the interval of 0.974 - 0.979. (author)

  13. Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach

    OpenAIRE

    Das, Biswa R.; Willis, David B.; Johnson, Jeffrey W.

    2010-01-01

    Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither signifi...

  14. Effectiveness of Two Water Conservation Policies: An Integrated Modeling Approach

    OpenAIRE

    Das, Biswa R.; Willis, David B.; Johnson, Jeffrey W.

    2010-01-01

    Agriculture in the Texas High Plains depends entirely on the Ogallala Aquifer. Texas enacted water conservation legislation to address declining reserves in the aquifer. We developed an integrated regional water policy model that links a hydrology model with an economic optimization model to estimate policy impacts with respect to economic cost and water conservation. Testing the effectiveness of two policies, a groundwater extraction tax and extraction quotas, we observe that neither signifi...

  15. Monte Carlo modeling of 60 Co HDR brachytherapy source in water and in different solid water phantom materials

    Directory of Open Access Journals (Sweden)

    Sahoo S

    2010-01-01

    Full Text Available The reference medium for brachytherapy dose measurements is water. Accuracy of dose measurements of brachytherapy sources is critically dependent on precise measurement of the source-detector distance. A solid phantom can be precisely machined and hence source-detector distances can be accurately determined. In the present study, four different solid phantom materials such as polymethylmethacrylate (PMMA, polystyrene, Solid Water, and RW1 are modeled using the Monte Carlo methods to investigate the influence of phantom material on dose rate distributions of the new model of BEBIG 60 Co brachytherapy source. The calculated dose rate constant is 1.086 ± 0.06% cGy h−1 U−1 for water, PMMA, polystyrene, Solid Water, and RW1. The investigation suggests that the phantom materials RW1 and Solid Water represent water-equivalent up to 20 cm from the source. PMMA and polystyrene are water-equivalent up to 10 cm and 15 cm from the source, respectively, as the differences in the dose data obtained in these phantom materials are not significantly different from the corresponding data obtained in liquid water phantom. At a radial distance of 20 cm from the source, polystyrene overestimates the dose by 3% and PMMA underestimates it by about 8% when compared to the corresponding data obtained in water phantom.

  16. Evaluating water conservation and reuse policies using a dynamic water balance model.

    Science.gov (United States)

    Qaiser, Kamal; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R

    2013-02-01

    A dynamic water balance model is created to examine the effects of different water conservation policies and recycled water use on water demand and supply in a region faced with water shortages and significant population growth, the Las Vegas Valley (LVV). The model, developed using system dynamics approach, includes an unusual component of the water system, return flow credits, where credits are accrued for returning treated wastewater to the water supply source. In LVV, Lake Mead serves as, both the drinking water source and the receiving body for treated wastewater. LVV has a consumptive use allocation from Lake Mead but return flow credits allow the water agency to pull out additional water equal to the amount returned as treated wastewater. This backdrop results in a scenario in which conservation may cause a decline in the available water supply. Current water use in LVV is 945 lpcd (250 gpcd), which the water agency aims to reduce to 752 lpcd (199 gpcd) by 2035, mainly through water conservation. Different conservation policies focused on indoor and outdoor water use, along with different population growth scenarios, are modeled for their effects on the water demand and supply. Major contribution of this study is in highlighting the importance of outdoor water conservation and the effectiveness of reducing population growth rate in addressing the future water shortages. The water agency target to decrease consumption, if met completely through outdoor conservation, coupled with lower population growth rate, can potentially satisfy the Valley's water demands through 2035.

  17. [Watershed water environment pollution models and their applications: a review].

    Science.gov (United States)

    Zhu, Yao; Liang, Zhi-Wei; Li, Wei; Yang, Yi; Yang, Mu-Yi; Mao, Wei; Xu, Han-Li; Wu, Wei-Xiang

    2013-10-01

    Watershed water environment pollution model is the important tool for studying watershed environmental problems. Through the quantitative description of the complicated pollution processes of whole watershed system and its parts, the model can identify the main sources and migration pathways of pollutants, estimate the pollutant loadings, and evaluate their impacts on water environment, providing a basis for watershed planning and management. This paper reviewed the watershed water environment models widely applied at home and abroad, with the focuses on the models of pollutants loading (GWLF and PLOAD), water quality of received water bodies (QUAL2E and WASP), and the watershed models integrated pollutant loadings and water quality (HSPF, SWAT, AGNPS, AnnAGNPS, and SWMM), and introduced the structures, principles, and main characteristics as well as the limitations in practical applications of these models. The other models of water quality (CE-QUAL-W2, EFDC, and AQUATOX) and watershed models (GLEAMS and MIKE SHE) were also briefly introduced. Through the case analysis on the applications of single model and integrated models, the development trend and application prospect of the watershed water environment pollution models were discussed.

  18. DEVELOPMENT AND APPLICATION OF A EUTROPHICATION WATER QUALITY MODEL FOR RIVER NETWORKS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Preissmann implicit scheme was used to discretize the one-dimensional Saint-Venant equations, the river-junction-river method was applied to resolve the hydrodynamic and water quality model for river networks, and the key issues on the model were expatiated particularly in this article. This water quality module was designed to compute time dependent concentrations of a series of constituents, which are primarily governed by the processes of advection, dispersion and chemical reactions. Based on the theory of Water Quality Analysis Simulation Program (WASP) water quality model, emphasis was given to the simulation of the biogeochemical transformations that determine the fate of nutrients, in particular, the simulation of the aquatic cycles of nitrogen and phosphorus compounds. This model also includes procedures for the determination of growth and death of phytoplankton. This hydrodynamic and water quality model was applied to calculate two river networks. As illustrated by the numerical examples, the calculated water level and discharge agree with the measured data and the simulated trends and magnitudes of water quality constituents are generally in good agreement with field observations. It is concluded that the presented model is useful in the pollutant control and in the determination of pollutant-related problems for river networks.

  19. Determining Regional Sensitivity to Energy-Related Water Withdrawals in Minnesota

    Science.gov (United States)

    McCulloch, A.; Brauman, K. A.

    2015-12-01

    Minnesota has abundant freshwater resources, yet concerns about water-impacts of energy and mining development are increasing. Statewide, total annual water withdrawals have increased, and, in some watersheds, withdrawals make up a large fraction of available water. The energy and mining sectors play a critical role in determining water availability, as water is used to irrigate biofuel feedstock crops, cool thermoelectric plants, and process and transport fuels and iron ore. We evaluated the Minnesota Department of Natural Resources (DNR) Water and Reporting System (MPARS) dataset (1988-2014) to identify regions where energy and mining-related water withdrawals are high or where they are increasing. The energy and mining sectors account for over 65 percent of total water extractions in Minnesota, but this percentage is greater in some regions. In certain southern and northeastern Minnesota watersheds, these extractions account for 90 percent of total water demand. Sensitivity to these demands is not dependent on total water demand alone, and is also not uniform among watersheds. We identified and evaluated factors influencing sensitivity, including population, extraction type (surface water or groundwater), percentage of increased demand, and whether withdrawals are consumptive or not. We determined that southern Minnesota is particularly sensitive to increased water demands, because of growing biofuel and sand extraction industries (the products of which are used in hydraulic fracturing). In the last ten years, ethanol production in Minnesota has increased by 440 percent, and over fifteen refineries (each with a capacity over 1.1 billion gallons), have been built. These users primarily extract from surface water bodies within a few watersheds, compromising local supplies. As these energy-related industries continue to grow, so will the demand for freshwater resources. Determining regional sensitivity to increased demands will allow policy-makers to manage the

  20. COMPUTER MODELING OF SELECTED WATER QUALITY PARAMETERS IN WATER DISTRIBUTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Wojciech Kruszyński

    2016-06-01

    Full Text Available The paper presents the results of computer modeling of flowsand the age of the water in two rural communi-ties province Podlasie - Rutka and Jeleniewo. The model is made using Epanet. In the study, a series of variants of models simulating the behavior of existing distribution systems and water analyzes were performed century. Analysis of the age of the water in water works modeled showed areas where standing water is aging, not having the estuary and not giving way to fresh. Age of water in the pipes is an important indicator of its quality and shelf life. The longer standing water in the aqueduct, the more likely that it will develop dangerous bacteria and produce deposits which remain on the walls of the ducts.

  1. Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) for the determination of [Zn(2+)] in estuarine waters.

    Science.gov (United States)

    Pearson, Holly B C; Galceran, Josep; Companys, Encarna; Braungardt, Charlotte; Worsfold, Paul; Puy, Jaume; Comber, Sean

    2016-03-17

    Zinc (Zn) has been classified as a "Specific Pollutant" under Annex VIII of the EU Water Framework Directive by two thirds of the EU member states. As a result, the UK Environmental Quality Standard (EQS) for Transitional and Coastal (TrAC) Waters has been reduced from 612 nM to 121 nM total dissolved Zn. It is widely accepted that the free metal ion ([Zn(2+)]) is the most bioavailable fraction, but there are few techniques available to determine its concentration in these waters. In this work, Absence of Gradients and Nernstian Equilibrium Stripping (AGNES) has been applied, for the first time, to determine [Zn(2+)] in estuarine waters. The AGNES method had a mean RSD of ±18%, a (deposition time dependent) limit of detection of 0.73 nM and a [Zn(2+)] recovery of 112 ± 19% from a certified reference material (BCR-505; Estuarine Water). AGNES results for 13 estuarine samples (salinity 0.1-31.9) compared well (P = 0.02) with Competitive Ligand Exchange Cathodic Stripping Voltammetry (CLE-AdCSV) except for one sample. AGNES requires minimal sample manipulation, is unaffected by adsorption of interfering species at the electrode surface and allows direct determination of free zinc ion concentrations. Therefore AGNES results can be used in conjunction with ecotoxicological studies and speciation modelling to set and test compliance with water quality standards. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Bayesian model selection applied to artificial neural networks used for water resources modeling

    Science.gov (United States)

    Kingston, Greer B.; Maier, Holger R.; Lambert, Martin F.

    2008-04-01

    Artificial neural networks (ANNs) have proven to be extremely valuable tools in the field of water resources engineering. However, one of the most difficult tasks in developing an ANN is determining the optimum level of complexity required to model a given problem, as there is no formal systematic model selection method. This paper presents a Bayesian model selection (BMS) method for ANNs that provides an objective approach for comparing models of varying complexity in order to select the most appropriate ANN structure. The approach uses Markov Chain Monte Carlo posterior simulations to estimate the evidence in favor of competing models and, in this study, three known methods for doing this are compared in terms of their suitability for being incorporated into the proposed BMS framework for ANNs. However, it is acknowledged that it can be particularly difficult to accurately estimate the evidence of ANN models. Therefore, the proposed BMS approach for ANNs incorporates a further check of the evidence results by inspecting the marginal posterior distributions of the hidden-to-output layer weights, which unambiguously indicate any redundancies in the hidden layer nodes. The fact that this check is available is one of the greatest advantages of the proposed approach over conventional model selection methods, which do not provide such a test and instead rely on the modeler's subjective choice of selection criterion. The advantages of a total Bayesian approach to ANN development, including training and model selection, are demonstrated on two synthetic and one real world water resources case study.

  3. Using stable isotopes to determine seasonal variations in water uptake of summer maize under different fertilization treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ying, E-mail: maying@igsnrr.ac.cn [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 210008 Nanjing (China); Song, Xianfang [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101 Beijing (China)

    2016-04-15

    Fertilization and water both affect root water uptake in the nutrient and water cycle of the Soil-Plant-Atmosphere-Continuum (SPAC). In this study, dual stable isotopes (D and {sup 18}O) were used to determine seasonal variations in water uptake patterns of summer maize under different fertilization treatments in Beijing, China during 2013–2014. The contributions of soil water at different depths to water uptake were quantified by the MixSIAR Bayesian mixing model. Water uptake was mainly sourced from soil water in the 0–20 cm depth at the seeding (67.7%), jointing (60.5%), tasseling (47.5%), dough (41.4%), and harvest (43.9%) stages, and the 20–50 cm depth at the milk stage (32.8%). Different levels of fertilization application led to considerable differences in the proportional contribution of soil water at 0–20 cm (6.0–58.5%) and 20–50 cm (6.1–26.3%). There was little difference of contributions in the deep layers (50–200 cm) among treatments in 2013, whereas differences were observed in 50–90 cm at the milk stage and 50–200 cm at the dough stage during 2014. The main water uptake depth was concentrated in the upper soil layers (0–50 cm) during the wet season (2013), whereas a seasonal drought in 2014 promoted the contribution of soil water in deep layers. The contribution of soil water was significantly and positively correlated with the proportions of root length (r = 0.753, p < 0.01). The changes of soil water distribution were consistent with the seasonal variation in water uptake patterns. The present study identified water sources for summer maize under varying fertilization treatments and provided scientific implications for fertilization and irrigation management. - Highlights: • Dual stable isotopes and MixSIAR were coupled to quantify water uptake of maize. • Maize mainly used soil water in 20–50 cm at milk stage and 0–20 cm at other stages. • Fertilization treatments led to distinct water uptake pattern at 0–50 cm

  4. Determination of Aluminium and Physicochemical Parameters in the Palm Oil Estates Water Supply at Johor, Malaysia

    Science.gov (United States)

    Siti Farizwana, M. R.; Mazrura, S.; Zurahanim Fasha, A.; Ahmad Rohi, G.

    2010-01-01

    The study was to determine the concentration of aluminium (Al) and study the physicochemical parameters (pH, total dissolved solids (TDS), turbidity, and residual chlorine) in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S), the treatment plant outlet (TPO), and at the nearest houses (H1) and the furthest houses (H2) from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90). The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU). Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L). Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems. PMID:21461348

  5. Determination of water states and the structural parameters of W/O microemulsions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The states of water in sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/isooctane/water reverse(W/O) microemulsions system have been investigated by using Fourier transform infrared spectroscopy(FT-IR) technique. The broad peak obtained for hydroxy(O-H) of water has been resolved by least square curve-fitting. It has been observed that the water solubilized in microemulsion droplets has four states, i.e. bound water with sulfo-group, free water, bound water with sodium counterion in the water pool of microemulsion droplets and a small amount of trapped water in the palisade layer of microemulsion droplets. The following have also been determined: the aggregation number (n), the radius of the water pool in the microemulsions(rw), the thickness of the bound water with sulfo-group(d1), the thickness of the bound water with sodium counterion(d2), the total thickness of the bound water ( d ) and the effective area of head groups of AOT(AAOT).

  6. Determination of aluminium and physicochemical parameters in the palm oil estates water supply at Johor, Malaysia.

    Science.gov (United States)

    Siti Farizwana, M R; Mazrura, S; Zurahanim Fasha, A; Ahmad Rohi, G

    2010-01-01

    The study was to determine the concentration of aluminium (Al) and study the physicochemical parameters (pH, total dissolved solids (TDS), turbidity, and residual chlorine) in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S), the treatment plant outlet (TPO), and at the nearest houses (H1) and the furthest houses (H2) from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90). The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU). Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L). Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems.

  7. Determination of Aluminium and Physicochemical Parameters in the Palm Oil Estates Water Supply at Johor, Malaysia

    Directory of Open Access Journals (Sweden)

    M. R. Siti Farizwana

    2010-01-01

    Full Text Available The study was to determine the concentration of aluminium (Al and study the physicochemical parameters (pH, total dissolved solids (TDS, turbidity, and residual chlorine in drinking water supply in selected palm oil estates in Kota Tinggi, Johor. Water samples were collected from the estates with the private and the public water supplies. The sampling points were at the water source (S, the treatment plant outlet (TPO, and at the nearest houses (H1 and the furthest houses (H2 from the TPO. All estates with private water supply failed to meet the NSDWQ for Al with mean concentration of 0.99 ± 1.52 mg/L. However, Al concentrations in all public water supply estates were well within the limit except for one estate. The pH for all samples complied with the NSDWQ except from the private estates for the drinking water supply with an acidic pH (5.50 ± 0.90. The private water supply showed violated turbidity value in the drinking water samples (14.2 ± 24.1 NTU. Insufficient amount of chlorination was observed in the private water supply estates (0.09 ± 0.30 mg/L. Private water supplies with inefficient water treatment served unsatisfactory drinking water quality to the community which may lead to major health problems.

  8. The decisive role of free water in determining homogenous ice nucleation behavior of aqueous solutions.

    Science.gov (United States)

    Wang, Qiang; Zhao, Lishan; Li, Chenxi; Cao, Zexian

    2016-05-26

    It is a challenging issue to quantitatively characterize how the solute and pressure affect the homogeneous ice nucleation in a supercooled solution. By measuring the glass transition behavior of solutions, a universal feature of water-content dependence of glass transition temperature is recognized, which can be used to quantify hydration water in solutions. The amount of free water can then be determined for water-rich solutions, whose mass fraction, Xf, is found to serve as a universal relevant parameter for characterizing the homogeneous ice nucleation temperature, the meting temperature of primary ice, and even the water activity of solutions of electrolytes and smaller organic molecules. Moreover, the effects of hydrated solute and pressure on ice nucleation is comparable, and the pressure, when properly scaled, can be incorporated into the universal parameter Xf. These results help establish the decisive role of free water in determining ice nucleation and other relevant properties of aqueous solutions.

  9. Effects of spatially distributed sectoral water management on the redistribution of water resources in an integrated water model

    Science.gov (United States)

    Voisin, Nathalie; Hejazi, Mohamad I.; Leung, L. Ruby; Liu, Lu; Huang, Maoyi; Li, Hong-Yi; Tesfa, Teklu

    2017-05-01

    Realistic representations of sectoral water withdrawals and consumptive demands and their allocation to surface and groundwater sources are important for improving modeling of the integrated water cycle. To inform future model development, we enhance the representation of water management in a regional Earth system (ES) model with a spatially distributed allocation of sectoral water demands simulated by a regional integrated assessment (IA) model to surface and groundwater systems. The integrated modeling framework (IA-ES) is evaluated by analyzing the simulated regulated flow and sectoral supply deficit in major hydrologic regions of the conterminous U.S, which differ from ES studies looking at water storage variations. Decreases in historical supply deficit are used as metrics to evaluate IA-ES model improvement in representating the complex sectoral human activities for assessing future adaptation and mitigation strategies. We also assess the spatial changes in both regulated flow and unmet demands, for irrigation and nonirrigation sectors, resulting from the individual and combined additions of groundwater and return flow modules. Results show that groundwater use has a pronounced regional and sectoral effect by reducing water supply deficit. The effects of sectoral return flow exhibit a clear east-west contrast in the hydrologic patterns, so the return flow component combined with the IA sectoral demands is a major driver for spatial redistribution of water resources and water deficits in the US. Our analysis highlights the need for spatially distributed sectoral representation of water management to capture the regional differences in interbasin redistribution of water resources and deficits.

  10. [Rapid determination of COD in aquaculture water based on LS-SVM with ultraviolet/visible spectroscopy].

    Science.gov (United States)

    Liu, Xue-Mei; Zhang, Hai-Liang

    2014-10-01

    Ultraviolet/visible (UV/Vis) spectroscopy was studied for the rapid determination of chemical oxygen demand (COD), which was an indicator to measure the concentration of organic matter in aquaculture water. In order to reduce the influence of the absolute noises of the spectra, the extracted 135 absorbance spectra were preprocessed by Savitzky-Golay smoothing (SG), EMD, and wavelet transform (WT) methods. The preprocessed spectra were then used to select latent variables (LVs) by partial least squares (PLS) methods. Partial least squares (PLS) was used to build models with the full spectra, and back- propagation neural network (BPNN) and least square support vector machine (LS-SVM) were applied to build models with the selected LVs. The overall results showed that BPNN and LS-SVM models performed better than PLS models, and the LS-SVM models with LVs based on WT preprocessed spectra obtained the best results with the determination coefficient (r2) and RMSE being 0. 83 and 14. 78 mg · L(-1) for calibration set, and 0.82 and 14.82 mg · L(-1) for the prediction set respectively. The method showed the best performance in LS-SVM model. The results indicated that it was feasible to use UV/Vis with LVs which were obtained by PLS method, combined with LS-SVM calibration could be applied to the rapid and accurate determination of COD in aquaculture water. Moreover, this study laid the foundation for further implementation of online analysis of aquaculture water and rapid determination of other water quality parameters.

  11. Monitoring And Modeling Environmental Water Quality To Support Environmental Water Purchase Decision-making

    Science.gov (United States)

    Null, S. E.; Elmore, L.; Mouzon, N. R.; Wood, J. R.

    2016-12-01

    More than 25 million cubic meters (20,000 acre feet) of water has been purchased from willing agricultural sellers for environmental flows in Nevada's Walker River to improve riverine habitat and connectivity with downstream Walker Lake. Reduced instream flows limit native fish populations, like Lahontan cutthroat trout, through warm daily stream temperatures and low dissolved oxygen concentrations. Environmental water purchases maintain instream flows, although effects on water quality are more varied. We use multi-year water quality monitoring and physically-based hydrodynamic and water quality modeling to estimate streamflow, water temperature, and dissolved oxygen concentrations with alternative environmental water purchases. We simulate water temperature and dissolved oxygen changes from increased streamflow to prioritize the time periods and locations that environmental water purchases most enhance trout habitat as a function of water quality. Monitoring results indicate stream temperature and dissolved oxygen limitations generally exist in the 115 kilometers upstream of Walker Lake (about 37% of the study area) from approximately May through September, and this reach acts as a water quality barrier for fish passage. Model results indicate that low streamflows generally coincide with critically warm stream temperatures, water quality refugia exist on a tributary of the Walker River, and environmental water purchases may improve stream temperature and dissolved oxygen conditions for some reaches and seasons, especially in dry years and prolonged droughts. This research supports environmental water purchase decision-making and allows water purchase decisions to be prioritized with other river restoration alternatives.

  12. Suitability of a Coupled Hydrodynamic Water Quality Model to Predict Changes in Water Quality from Altered Meteorological Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Leon van der Linden

    2015-01-01

    Full Text Available Downscaled climate scenarios can be used to inform management decisions on investment in infrastructure or alternative water sources within water supply systems. Appropriate models of the system components, such as catchments, rivers, lakes and reservoirs, are required. The climatic sensitivity of the coupled hydrodynamic water quality model ELCOM-CAEDYM was investigated, by incrementally altering boundary conditions, to determine its suitability for evaluating climate change impacts. A series of simulations were run with altered boundary condition inputs for the reservoir. Air and inflowing water temperature (TEMP, wind speed (WIND and reservoir inflow and outflow volumes (FLOW were altered to investigate the sensitivity of these key drivers over relevant domains. The simulated water quality variables responded in broadly plausible ways to the altered boundary conditions; sensitivity of the simulated cyanobacteria population to increases in temperature was similar to published values. However the negative response of total chlorophyll-a suggested by the model was not supported by an empirical analysis of climatic sensitivity. This study demonstrated that ELCOM-CAEDYM is sensitive to climate drivers and may be suitable for use in climate impact studies. It is recommended that the influence of structural and parameter derived uncertainty on the results be evaluated. Important factors in determining phytoplankton growth were identified and the importance of inflowing water quality was emphasized.

  13. A novel water poverty index model for evaluation of Chinese regional water security

    Science.gov (United States)

    Gong, L.; Jin, C. L.; Li, Y. X.; Zhou, Z. L.

    2017-08-01

    This study proposed an improved Water Poverty Index (WPI) model employed in evaluating Chinese regional water security. Firstly, the Chinese WPI index system was constructed, in which the indicators were obtained according to China River reality. A new mathematical model was then established for WPI values calculation on the basis of Center for Ecology and Hydrology (CEH) model. Furthermore, this new model was applied in Shiyanghe River (located in western China). It turned out that the Chinese index system could clearly reflect the indicators threatening security of river water and the Chinese WPI model is feasible. This work has also developed a Water Security Degree (WSD) standard which is able to be regarded as a scientific basis for further water resources utilization and water security warning mechanism formulation.

  14. Integrating the simulation of domestic water demand behaviour to an urban water model using agent based modelling

    Science.gov (United States)

    Koutiva, Ifigeneia; Makropoulos, Christos

    2015-04-01

    The urban water system's sustainable evolution requires tools that can analyse and simulate the complete cycle including both physical and cultural environments. One of the main challenges, in this regard, is the design and development of tools that are able to simulate the society's water demand behaviour and the way policy measures affect it. The effects of these policy measures are a function of personal opinions that subsequently lead to the formation of people's attitudes. These attitudes will eventually form behaviours. This work presents the design of an ABM tool for addressing the social dimension of the urban water system. The created tool, called Urban Water Agents' Behaviour (UWAB) model, was implemented, using the NetLogo agent programming language. The main aim of the UWAB model is to capture the effects of policies and environmental pressures to water conservation behaviour of urban households. The model consists of agents representing urban households that are linked to each other creating a social network that influences the water conservation behaviour of its members. Household agents are influenced as well by policies and environmental pressures, such as drought. The UWAB model simulates behaviour resulting in the evolution of water conservation within an urban population. The final outcome of the model is the evolution of the distribution of different conservation levels (no, low, high) to the selected urban population. In addition, UWAB is implemented in combination with an existing urban water management simulation tool, the Urban Water Optioneering Tool (UWOT) in order to create a modelling platform aiming to facilitate an adaptive approach of water resources management. For the purposes of this proposed modelling platform, UWOT is used in a twofold manner: (1) to simulate domestic water demand evolution and (2) to simulate the response of the water system to the domestic water demand evolution. The main advantage of the UWAB - UWOT model

  15. Determining the in situ water content of the Geysers Graywacke of Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, A.

    1994-12-01

    The water content, porosity and permeability measurements of the Northern California Geysers rocks are used to predict the lifetime of the geothermal resource, which provides 10% of Northern California`s electricity. The Geysers rock was drilled from defunct well SB-15-D, and some cores wee sealed in aluminum tubes to preserve the in situ water content. These cores were sent to the Lawrence Livermore Laboratory to measure the water content. Humidity measurements were taken of the air around a one and a half foot encased core, recovered from a depth of 918.9 feet. Over a seven day period, the humidity reached almost 100% indicating that the air around the core was saturated in water vapor. We believe the sealing method is effective, preserving the in-situ water content. To measure water content, I will use Archimede`s principle to determine the density of the core before and after drying in an oven. Ultrasonic measurements will be taken of the core upon removal from aluminum tube to determine the change of p-wave velocity with change in water content. Water in the pores increases the effective compressibility of the rock therefore increasing the p-velocity. The measured p-wave velocities can then be used in the field to determine in-situ water content. Three dimensional x-ray images will be used to determine the deviations from average density within individual cores. Since the density depends on water content as well as mineralogy, images can show the location of pore fluid and drilling mud. Archimede`s principle, humidity detection, ultrasonics and x-ray scanning are viable methods to measure the in-situ water content and pore water distribution in the graywacke.

  16. DETERMINATION OF ORGANOCHLORINE PESTICIDES IN DRINKING WATERS SAMPLED FROM CLUJ AND HUNEDOARA COUNTIES

    OpenAIRE

    MARIA-ELISABETA LOVÁSZ; IRINA DUMITRAŞCU; OVIDIU TRAIAN POPA; ANCA ELENA GURZĂU

    2011-01-01

    Determination of organochlorine pesticides in drinking waterssampled from Cluj and Hunedoara counties. Pesticides are found scattered indifferent environmental factors (water, air, soil) wherefrom they are drawn off byvegetal and animal organisms. Water pollution by pesticides results from the plantprotection products industry and also from massive application of these resourcesin agriculture and other branches of economy. Pesticides can reach surface wateralong with dripping waters and by in...

  17. Technical Note: The determination of enclosed water volume in large flexible-wall mesocosms "KOSMOS"

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2013-03-01

    Full Text Available The volume of water enclosed inside flexible-wall mesocosm bags is hard to estimate using geometrical calculations and can be strongly variable among bags of the same dimensions. Here we present a method for precise water volume determination in mesocosms using salinity as a tracer. Knowledge of the precise volume of water enclosed allows establishment of exactly planned treatment concentrations and calculation of elemental budgets.

  18. Inter-basin water transfer-supply model and risk analysis with consideration of rainfall forecast information

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper develops a new inter-basin water transfer-supply and risk assessment model with consideration of rainfall forecast information. Firstly, based on the current state of reservoir and rainfall forecast information from the global forecast system (GFS), the actual diversion amount can be determined according to the inter-basin water transfer rules with the decision tree method; secondly, the reservoir supply operation system is used to distribute water resource of the inter-basin water transfer reservoir; finally, the integrated risk assessment model is built by selecting the reliability of water transfer, the reliability (water shortage risk), the resiliency and the vulnerability of water supply as risk analysis indexes. The case study shows that the inter-basin water transfer-supply model with rainfall forecast information considered can reduce the comprehensive risk and improve the utilization efficiency of water resource, as compared with conventional and optimal water distribution models.

  19. Simple Method to Determine the Partition Coefficient of Naphthenic Acid in Oil/Water

    DEFF Research Database (Denmark)

    Bitsch-Larsen, Anders; Andersen, Simon Ivar

    2008-01-01

    The partition coefficient for technical grade naphthenic acid in water/n-decane at 295 K has been determined (K-wo = 2.1 center dot 10(-4)) using a simple experimental technique with large extraction volumes (0.09 m(3) of water). Furthermore, nonequilibrium values at different pH values are prese...

  20. Calorimetric determination of the water energy dosis; Kalorimetrische Bestimmung der Wasser-Energiedosis

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, Achim [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Einheit der Wasser-Energiedosis'

    2013-06-15

    The water calorimeter of the PTB is described, which consists of a water phantom operated at 4 C, whereby the radiation-induced temperature raise is measured by means of thermistors. As application example the determination of the radiation-quality dependent k{sub Q} factors of ionization chambers for all medical accelerators present in the PTB is described. (HSI)

  1. A simple apparatus for the determining contact angle of water repellent fabrics

    Directory of Open Access Journals (Sweden)

    B. M. Banerji

    1955-04-01

    Full Text Available A simple apparatus for the determination of fabric-water contact angle of water repellent fabrics is described. It is based on the tilting plate principle and the additional advantage that the end point can be sharply ascertained by optical means.

  2. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    Science.gov (United States)

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  3. Water production in comet 81P/Wild 2 as determined by Herschel/HIFI

    NARCIS (Netherlands)

    de Val-Borro, M.; Hartogh, P.; Crovisier, J.; Bockelee-Morvan, D.; Biver, N.; Lis, D. C.; Moreno, R.; Jarchow, C.; Rengel, M.; Szutowicz, S.; Banaszkiewicz, M.; Bensch, F.; Blecka, M. I.; Emprechtinger, M.; Encrenaz, T.; Jehin, E.; Kueppers, M.; Lara, L. -M.; Lellouch, E.; Swinyard, B. M.; Vandenbussche, B.; Bergin, E. A.; Blake, G.A.; Blommaert, J. A. D. L.; Cernicharo, J.; Decin, L.; Encrenaz, P.; de Graauw, T.; Hutsemekers, D.; Kidger, M.; Manfroid, J.; Medvedev, A. S.; Naylor, D. A.; Schieder, R.; Stam, D.; Thomas, N.; Waelkens, C.; Szczerba, R.; Saraceno, P.; Di Giorgio, A. M.; Philipp, S.; Klein, T.; Ossenkopf, V.; Zaal, P.; Shipman, R.

    2010-01-01

    The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this Letter we present HIFI observations of the fundamental 1(10)-1(01) (557 GHz) ortho and 1(11)-0(00) (1113

  4. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    Science.gov (United States)

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  5. A simple flow-concentration modelling method for integrating water ...

    African Journals Online (AJOL)

    DRINIE

    2003-07-03

    Jul 3, 2003 ... a useful screening tool for identifying sites where, without reduction of pollution, the water ... or “Q-C” modelling method) developed to inter-relate water quality ..... Pretoria. 7/1-7/33. MALAN HL and DAY JA (2002a) Development of Numerical ... (1996) Trends in New Zealand's national river water quality.

  6. MATHEMATICAL MODEL OF PURIFICATION PROCESS OF OIL CONTAMINATED WATERS

    Directory of Open Access Journals (Sweden)

    С. Бойченко

    2012-04-01

    Full Text Available Sorption properties of carbonic sorbents on natural raw materials for purification of waste waters frompetroleum products are investigated. Temperature influence on sumption properties of sorbents on naturalraw materials to increase the purification degree of water ecosystem is studied. Mathematical model ofpurification process of oil contaminated waters is developed

  7. MATHEMATICAL MODEL OF PURIFICATION PROCESS OF OIL CONTAMINATED WATERS

    OpenAIRE

    С. Бойченко; Кучер, О.; Л. Павлюх

    2012-01-01

    Sorption properties of carbonic sorbents on natural raw materials for purification of waste waters frompetroleum products are investigated. Temperature influence on sumption properties of sorbents on naturalraw materials to increase the purification degree of water ecosystem is studied. Mathematical model ofpurification process of oil contaminated waters is developed

  8. Water production models for Comet Bradfield (1979 l)

    Science.gov (United States)

    Weaver, H. A.; Feldman, P. D.; Festou, M. C.

    1981-01-01

    The IUE observations of Comet Bradfield (1979 l) made 10 January 1980 to 3 March 1980 permit a detailed study of water production for this comet. Brightness measurements are presented for all three water dissociation products, H, O, and OH, and comparisons are made with model predictions. The heliocentric variation of the water production rate was derived.

  9. Determination of Chlorine Dioxide and Chlorite in Water Supply Systems by Verified Methods

    Science.gov (United States)

    Tkáčová, Jana; Božíková, Jarmila

    2014-07-01

    This work is dedicated to the development and optimization of appropriate analytical methods for the determination of chlorine dioxide and chlorite in drinking water in order to obtain accurate and correct results in the quality control of drinking water. The work deals with the development and optimization of a method for the determination of chlorine dioxide using chlorophenol red. Furthermore, a new spectrophotometric method for the determination of chlorite via bromometry using methyl orange was developed, optimized and validated. An electrochemical method for the determination of chlorite by flow coulometry was also developed, optimized and validated.

  10. Determination of Chlorine Dioxide and Chlorite in Water Supply Systems by Verified Methods

    Directory of Open Access Journals (Sweden)

    Tkáčová Jana

    2014-07-01

    Full Text Available This work is dedicated to the development and optimization of appropriate analytical methods for the determination of chlorine dioxide and chlorite in drinking water in order to obtain accurate and correct results in the quality control of drinking water. The work deals with the development and optimization of a method for the determination of chlorine dioxide using chlorophenol red. Furthermore, a new spectrophotometric method for the determination of chlorite via bromometry using methyl orange was developed, optimized and validated. An electrochemical method for the determination of chlorite by flow coulometry was also developed, optimized and validated.

  11. Determination of the amount of Cs-137 in the sea water obtained from the Dardanelles

    Science.gov (United States)

    Ataseven, D.; Şen, S.

    2017-02-01

    After the Chernobyl accident, high concentrations of Cs-137 radioisotope reached the Black Sea through dry and wet fallout. Therefore, a number of studies were performed to determine the current activity of Cs-137 near this region in the sea water and in marine organisms. Cs-137 activity was determined in the Dardanelles sea water taken from three separate locations and two different depths for each location. The old data base obtained in our previous studies was updated.

  12. Determination of trace organic impurities in water using thermal desorption from XAD resin

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, J.P.; Fritz, J.S.

    1978-10-01

    A small water sample (20 to 250 ml) is passed through a small tube containing XAD-4 resin; this effectively retains the organic impurities present in the water. This tube is connected to the permanent apparatus and the sorbed organics are thermally transferred to a small Tenex pre-column while the water vapor is vented. The pre-column is closed off, preheated to 275 to 280/sup 0/C, and then a valve is opened to plug-inject the vaporized sample into a gas chromatograph. The procedure works well for a variety of model organic compounds added to water and can be used for the analysis of actual water samples.

  13. Water Management in England: A Regional Model

    Science.gov (United States)

    Okun, Daniel A.

    1975-01-01

    Reorganization of authorities resulting in sound direction, greater flexibility, and more attention to cost effectiveness has helped the British achieve a high quality of water service. The history and development of British water management are reviewed and more cooperation between federal and state agencies is encouraged. (BT)

  14. WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL

    Science.gov (United States)

    Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

  15. Modelling Forest Water Consumption in The Netherlands

    NARCIS (Netherlands)

    Dolman, A.J.; Nonhebel, S.

    1988-01-01

    The water consumption of oak, beech, spruce and pine forest is predicted from routinely measured meteorological data for five locations in the Netherlands. Differences in water consumption are found to be primarily a result of differences in interception loss. Predicted interception loss was found t

  16. Flood modeling using WMS model for determining peak flood discharge in southwest Iran case study: Simili basin in Khuzestan Province

    Science.gov (United States)

    Hoseini, Yaser; Azari, Arash; Pilpayeh, Alireza

    2016-10-01

    It is of high importance to determine the flood discharge of different basins, in studies on water resources. However, it is necessary to use new models to determine flood hydrograph parameters. Therefore, it will be beneficial to conduct studies to calibrate the models, keeping in mind the local conditions of different regions. Therefore, this study was carried out to determine the peak flood discharge of a basin located in Southwest Iran, using the TR-20, TR55, and HEC-1 methods of the WMS model (watershed modeling system). The obtained results were compared with empirical values, as well as those of the soil conservation service (SCS) approach. Based on the results obtained, the TR55 method of the WMS model recorded the highest agreement with empirical values in Southwest Iran.

  17. Contemporary changes of water resources, water and land use in Central Asia based on observations and modeling.

    Science.gov (United States)

    Shiklomanov, A. I.; Prousevitch, A.; Sokolik, I. N.; Lammers, R. B.

    2015-12-01

    Water is a key agent in Central Asia ultimately determining human well-being, food security, and economic development. There are complex interplays among the natural and anthropogenic drivers effecting the regional hydrological processes and water availability. Analysis of the data combined from regional censuses and remote sensing shows a decline in areas of arable and irrigated lands and a significant decrease in availability of arable and irrigated lands per capita across all Central Asian countries since the middle of 1990thas the result of post-Soviet transformation processes. This change could lead to considerable deterioration in food security and human system sustainability. The change of political situation in the region has also resulted in the escalated problems of water demand between countries in international river basins. We applied the University of New Hampshire - Water Balance Model - Transport from Anthropogenic and Natural Systems (WBM-TrANS) to understand the consequences of changes in climate, water and land use on regional hydrological processes and water availability. The model accounts for sub-pixel land cover types, glacier and snow-pack accumulation/melt across sub-pixel elevation bands, anthropogenic water use (e.g. domestic and industrial consumption, and irrigation for most of existing crop types), hydro-infrastructure for inter-basin water transfer and reservoir/dam regulations. A suite of historical climate re-analysis and temporal extrapolation of MIRCA-2000 crop structure datasets has been used in WBM-TrANS for this project. A preliminary analysis of the model simulations over the last 30 years has shown significant spatial and temporal changes in hydrology and water availability for crops and human across the region due to climatic and anthropogenic causes. We found that regional water availability is mostly impacted by changes in extents and efficiency of crop filed irrigation, especially in highly arid areas of Central Asia

  18. Modelling of the water retention characteristic of deformable soils

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2016-01-01

    Full Text Available A recently proposed water retention model has been further developed for the application on unsaturated deformable soils. The physical mechanisms underpinning the water retention characteristic of soils was at first described in terms of traditional theories of capillarity and interfacial physical chemistry at pore level. Then upscaling to macroscopic level of material scale in terms of average volume theorem produces an analytical formula for the water retention characteristic. The methodology produces an explicit form of the water retention curve as a function of three state parameters: the suction, the degree-of-water-saturation and the void-ratio. At last, the model has been tested using experimental measurements.

  19. Determinants of business model performance in software firms

    OpenAIRE

    Rajala, Risto

    2009-01-01

    The antecedents and consequences of business model design have gained increasing interest among information system (IS) scholars and business practitioners alike. Based on an extensive literature review and empirical research, this study investigates the factors that drive business model design and the performance effects generated by the different kinds of business models in software firms. The main research question is: “What are the determinants of business model performance in the softwar...

  20. Determinants of agricultural water saving technology adoption: an empirical study of 10 provinces of China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In recent years,China has been faced by an increasingly severe water shortage due to the continua growth of demand on water resources.Although the Chinese government has been actively promoting the agricultural water-saving technology adoption,it is ill-informed of the adoption degree of the current agricultural water saving technologies as well as the function of the governmental policies.Therefore,this paper analyzes the aforesaid problems based on investigative data of 10 provinces in China.The results demonstrate that although there is a rapid increase of adopted agricultural water-saving technologies,the actual adoption area is rather limited.Moreover,the governmental policies and scarcity of water resources are the determinants of agricultural water-saving technology adoption.Ultimately,the paper proposes some policy suggestions.

  1. Health Belief Model and Reasoned Action Theory in Predicting Water Saving Behaviors in Yazd, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Ghaneian

    2012-12-01

    Full Text Available Background: People's behaviors and intentions about healthy behaviors depend on their beliefs, values, and knowledge about the issue. Various models of health education are used in deter-mining predictors of different healthy behaviors but their efficacy in cultural behaviors, such as water saving behaviors, are not studied. The study was conducted to explain water saving beha-viors in Yazd, Iran on the basis of Health Belief Model and Reasoned Action Theory. Methods: The cross-sectional study used random cluster sampling to recruit 200 heads of households to collect the data. The survey questionnaire was tested for its content validity and reliability. Analysis of data included descriptive statistics, simple correlation, hierarchical multiple regression. Results: Simple correlations between water saving behaviors and Reasoned Action Theory and Health Belief Model constructs were statistically significant. Health Belief Model and Reasoned Action Theory constructs explained 20.80% and 8.40% of the variances in water saving beha-viors, respectively. Perceived barriers were the strongest Predictor. Additionally, there was a sta-tistically positive correlation between water saving behaviors and intention. Conclusion: In designing interventions aimed at water waste prevention, barriers of water saving behaviors should be addressed first, followed by people's attitude towards water saving. Health Belief Model constructs, with the exception of perceived severity and benefits, is more powerful than is Reasoned Action Theory in predicting water saving behavior and may be used as a framework for educational interventions aimed at improving water saving behaviors.

  2. Water supply and demand in an energy supply model

    Energy Technology Data Exchange (ETDEWEB)

    Abbey, D; Loose, V

    1980-12-01

    This report describes a tool for water and energy-related policy analysis, the development of a water supply and demand sector in a linear programming model of energy supply in the United States. The model allows adjustments in the input mix and plant siting in response to water scarcity. Thus, on the demand side energy conversion facilities can substitute more costly dry cooling systems for conventional evaporative systems. On the supply side groundwater and water purchased from irrigators are available as more costly alternatives to unappropriated surface water. Water supply data is developed for 30 regions in 10 Western states. Preliminary results for a 1990 energy demand scenario suggest that, at this level of spatial analysis, water availability plays a minor role in plant siting. Future policy applications of the modeling system are discussed including the evaluation of alternative patterns of synthetic fuels development.

  3. Validation of water sorption-based clay prediction models for calcareous soils

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Razzaghi, Fatemeh; Moosavi, Ali

    2017-01-01

    Soil particle size distribution (PSD), particularly the active clay fraction, mediates soil engineering, agronomic and environmental functions. The tedious and costly nature of traditional methods of determining PSD prompted the development of water sorption-based models for determining the clay...

  4. A viscoelastic spring-block model for investigating subglacial water pressure pulse generation

    Science.gov (United States)

    Kavanaugh, J. L.

    2009-12-01

    A viscoelastic spring-block model of glacier motion has been developed to investigate the mechanisms responsible for generating brief pulses in subglacial water pressure recorded at Trapridge Glacier, Yukon. In this model, the glacier is treated as an array of ice blocks, each of which is connected to its nearest neighbors by spring-and-dashpot linkages. The model glacier is gravitationally driven, and down-slope flow is resisted by a basal shear stress determined by the Mohr-Coulomb failure criterion. This model is forced with realistic basal water pressure conditions. With prescribed summer-mode, diurnally-varying pressures, the model produces elevated slip activity at times of rising (rather than peak) water pressures; with steady, elevated winter-mode pressures, slip events occur at non-uniform intervals due to the effects of elastic loading and the (nonlinear) viscous relaxation of stresses. Magnitude and interevent time statistics for model slip events and basal water pressure pulses are compared.

  5. DETERMINATION OF ORGANOCHLORINE PESTICIDES IN DRINKING WATERS SAMPLED FROM CLUJ AND HUNEDOARA COUNTIES

    Directory of Open Access Journals (Sweden)

    MARIA-ELISABETA LOVÁSZ

    2011-03-01

    Full Text Available Determination of organochlorine pesticides in drinking waterssampled from Cluj and Hunedoara counties. Pesticides are found scattered indifferent environmental factors (water, air, soil wherefrom they are drawn off byvegetal and animal organisms. Water pollution by pesticides results from the plantprotection products industry and also from massive application of these resourcesin agriculture and other branches of economy. Pesticides can reach surface wateralong with dripping waters and by infiltration may reach the groundwater layers,organochlorine pesticides are most often found in the water sources (dieldrin,endrin, DDT, aldrin, lindane, heptachlor, etc. due to their increased persistence inthe external environment. This study followed up the determination oforganochlorine pesticides in 14 drinking water samples collected from the outputof water treatment plants in Cluj and Hunedoara counties that process surfacewater and deep-water sources. For identification of organochlorine pesticides, thegas chromatographic method after liquid-liquid extraction was used, by a gascromatograph Shimadzu GC 2010 with detector ECD (Electron CaptureDetection. There were not detected higher values than the method detection limit(0.01 μg/l in the drinking water samples collected and analyzed for both totalorganochlorine pesticides and components, which were well below the maximumconcentration admitted by Law 452/2002 regarding drinking water quality. Resultsare correlated with the sanitary protection areas for water sources and with the useof agricultural lands in the area. The solution to reduce risk of pesticides use isecological agriculture , which gains increasingly more ground in Romania too.

  6. Oscillatory water sorption test for determining water uptake behavior in bread crust

    NARCIS (Netherlands)

    Nieuwenhuijzen, N.H. van; Tromp, R.H.; Hamer, R.J.; Vliet, T. van

    2007-01-01

    In this work, water sorption kinetics of bread crust are described using an oscillatory sorption test in combination with a Langmuir type equation. Both kinetic and thermodynamic information could be obtained at the same time. An advantage of applying a Langmuir type equation for a quantitative desc

  7. Monetary models and exchange rate determination: The Nigerian ...

    African Journals Online (AJOL)

    Monetary models and exchange rate determination: The Nigerian evidence. ... income levels and real interest rate differentials provide better forecasts of the naira-US dollar ... in this regard is that monetary policy should be positively predicted.

  8. Health Belief Model and Reasoned Action Theory in Predicting Water Saving Behaviors in Yazd, Iran

    OpenAIRE

    Mohammad Taghi Ghaneian; Mahdieh Momayyezi; Mohammad Ali Morowatisharifabad

    2012-01-01

    Background: People's behaviors and intentions about healthy behaviors depend on their beliefs, values, and knowledge about the issue. Various models of health education are used in deter-mining predictors of different healthy behaviors but their efficacy in cultural behaviors, such as water saving behaviors, are not studied. The study was conducted to explain water saving beha-viors in Yazd, Iran on the basis of Health Belief Model and Reasoned Action Theory. Methods: The cross-sectional stud...

  9. Morphology of rain water channelization in systematically varied model sandy soils

    OpenAIRE

    Wei, Y.; Cejas, C. M.; Barrois, R.; Dreyfus, R.; Durian, D. J.

    2014-01-01

    We visualize the formation of fingered flow in dry model sandy soils under different raining conditions using a quasi-2d experimental set-up, and systematically determine the impact of soil grain diameter and surface wetting property on water channelization phenomenon. The model sandy soils we use are random closely-packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates into a shallow top layer of soil and...

  10. River water quality model no. 1 (RWQM1): I. Modelling approach

    DEFF Research Database (Denmark)

    Shanahan, P.; Borchardt, D.; Henze, Mogens

    2001-01-01

    Successful river water quality modelling requires the specification of an appropriate model structure and process formulation. Both must be related to the compartment structure of running water ecosystems including their longitudinal, vertical, and lateral zonation patterns. Furthermore, the temp...

  11. River water quality model no. 1 (RWQM1): I. Modelling approach

    DEFF Research Database (Denmark)

    Shanahan, P.; Borchardt, D.; Henze, Mogens

    2001-01-01

    Successful river water quality modelling requires the specification of an appropriate model structure and process formulation. Both must be related to the compartment structure of running water ecosystems including their longitudinal, vertical, and lateral zonation patterns. Furthermore...

  12. Crop kites: Determining crop-water production functions using crop coefficients and sensitivity indices

    Science.gov (United States)

    Smilovic, Mikhail; Gleeson, Tom; Adamowski, Jan

    2016-11-01

    The crop-water production function quantitatively evaluates the relationship between seasonal water use and crop yield and is used to evaluate optimal irrigation depth and assess the potential of deficit and supplemental irrigation. A simple and easily applicable methodology to develop crop- and region-specific crop-water production functions using crop coefficients and sensitivity-indices is presented. Previous efforts to describe the crop-water production function have not accounted for the effects of the temporal distribution of water use and trivialize the associated variability in yields by assuming an optimized or arbitrary temporal distribution. The temporal distribution of water use throughout the growing season can significantly influence crop yield, and the ability of farmers to manage both the timing and amount of irrigation water may result in higher yields. We propose crop kites, a tool that explicitly acknowledges crop yield as a function of the temporal distribution of water use to both evaluate the complete space of water use and crop yield relationships, and extract from this space specific crop-water production functions. An example for winter wheat is presented using previously validated crop-specific sensitivity indices. Crop-water production functions are extracted from the crop kite related to specific irrigation schedules and temporal distributions of water use. Crop-water production functions associated with maximizing agricultural production agree with previous efforts characterizing the shape as a diminishing curvilinear function. Crop kites provide the tools for water managers and policy makers to evaluate crop- and region-specific agricultural production as it relates to water management and the associated economics, and to determine appropriate policies for developing and supporting the infrastructure to increase water productivity.

  13. A sequential injection system for the spectrophotometric determination of calcium, magnesium and alkalinity in water samples.

    Science.gov (United States)

    Mesquita, Raquel B R; Rangel, António O S S

    2004-08-01

    A sequential injection methodology for the spectrophotometric determination of calcium, magnesium and alkalinity in water samples is proposed. A single manifold is used for the determination of the three analytes, and the same protocol sequence allows the sequential determination of calcium and magnesium (the sum corresponds to the water hardness). The determination of both metals is based on their reaction with cresolphtalein complexone; mutual interference is minimized by using 8-hydroxyquinoline for the determination of calcium and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) for the determination of magnesium. Alkalinity determination is based on a reaction with acetic acid, and corresponding color change of Bromcresol Green. Working ranges of 0.5 - 5 mg dm(-3) for Ca, 0.5 - 10 mg dm(-3) for Mg, and 10 - 100 mg HCO3- dm(-3), for alkalinity have been achieved. The results for water samples were comparable to those of the reference methods and to a certified reference water sample. RSDs lower than 5% were obtained, a low reagent consumption and a reduced volume of effluent have been accomplished. The determination rate for calcium and magnesium is 80 h(-1), corresponding to 40 h(-1) per element, while 65 determinations of alkalinity per hour could be carried out.

  14. Model Experiments for the Determination of Airflow in Large Spaces

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Model experiments are one of the methods used for the determination of airflow in large spaces. This paper will discuss the formation of the governing dimensionless numbers. It is shown that experiments with a reduced scale often will necessitate a fully developed turbulence level of the flow....... Details of the flow from supply openings are very important for the determination of room air distribution. It is in some cases possible to make a simplified supply opening for the model experiment....

  15. Assessing irrigated agriculture's surface water and groundwater consumption by combining satellite remote sensing and hydrologic modelling.

    Science.gov (United States)

    Peña-Arancibia, Jorge L; Mainuddin, Mohammed; Kirby, John M; Chiew, Francis H S; McVicar, Tim R; Vaze, Jai

    2016-01-15

    Globally, irrigation accounts for more than two thirds of freshwater demand. Recent regional and global assessments indicate that groundwater extraction (GWE) for irrigation has increased more rapidly than surface water extraction (SWE), potentially resulting in groundwater depletion. Irrigated agriculture in semi-arid and arid regions is usually from a combination of stored surface water and groundwater. This paper assesses the usefulness of remotely-sensed (RS) derived information on both irrigation dynamics and rates of actual evapotranspiration which are both input to a river-reach water balance model in order to quantify irrigation water use and water provenance (either surface water or groundwater). The assessment is implemented for the water-years 2004/05-2010/11 in five reaches of the Murray-Darling Basin (Australia); a heavily regulated basin with large irrigated areas and periodic droughts and floods. Irrigated area and water use are identified each water-year (from July to June) through a Random Forest model which uses RS vegetation phenology and actual evapotranspiration as predicting variables. Both irrigated areas and actual evapotranspiration from irrigated areas were compared against published estimates of irrigated areas and total water extraction (SWE+GWE).The river-reach model determines the irrigated area that can be serviced with stored surface water (SWE), and the remainder area (as determined by the Random Forest Model) is assumed to be supplemented by groundwater (GWE). Model results were evaluated against observed SWE and GWE. The modelled SWE generally captures the observed interannual patterns and to some extent the magnitudes, with Pearson's correlation coefficients >0.8 and normalised root-mean-square-errormodelling. The RS irrigated areas and actual evapotranspiration can be used to: (i) understand irrigation dynamics, (ii) constrain irrigation models in data scarce regions, as well as (iii) pinpointing areas that require better ground

  16. Determination of strontium in drinking water and consequences of radioactive elements present in drinking water for human health

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available In this paper the analysis of strontium and uranium content in drinking water has been done, indirectly, according to the scale which originates from drinking water in water-supply system of the city of Belgrade. Gamaspectrometric analysis showed the presence of free natural radionuclide in low activities. The activity of 90Sr in scale which is 0.72±0.11 Bq/kg was determined by radiochemical. Because of the small quantities of fur in the house heater this activity can be considered as irrelevant, but the accumulation of scale can have intensified influence. In this paper, the analysis of effects of the radioactive isotopes presence (first of all 238U and 235U in drinking water on human health has been done. .

  17. Modeling Equity for Alternative Water Rate Structures

    Science.gov (United States)

    Griffin, R.; Mjelde, J.

    2011-12-01

    The rising popularity of increasing block rates for urban water runs counter to mainstream economic recommendations, yet decision makers in rate design forums are attracted to the notion of higher prices for larger users. Among economists, it is widely appreciated that uniform rates have stronger efficiency properties than increasing block rates, especially when volumetric prices incorporate intrinsic water value. Yet, except for regions where water market purchases have forced urban authorities to include water value in water rates, economic arguments have weakly penetrated policy. In this presentation, recent evidence will be reviewed regarding long term trends in urban rate structures while observing economic principles pertaining to these choices. The main objective is to investigate the equity of increasing block rates as contrasted to uniform rates for a representative city. Using data from four Texas cities, household water demand is established as a function of marginal price, income, weather, number of residents, and property characteristics. Two alternative rate proposals are designed on the basis of recent experiences for both water and wastewater rates. After specifying a reasonable number (~200) of diverse households populating the city and parameterizing each household's characteristics, every household's consumption selections are simulated for twelve months. This procedure is repeated for both rate systems. Monthly water and wastewater bills are also computed for each household. Most importantly, while balancing the budget of the city utility we compute the effect of switching rate structures on the welfares of households of differing types. Some of the empirical findings are as follows. Under conditions of absent water scarcity, households of opposing characters such as low versus high income do not have strong preferences regarding rate structure selection. This changes as water scarcity rises and as water's opportunity costs are allowed to

  18. Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry

    Science.gov (United States)

    Chao, T.T.; Fishman, M. J.; Ball, J.W.

    1969-01-01

    A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

  19. Sorption capacities of graphitzed carbon black in determination of chlorinate pesticide traces in water

    Energy Technology Data Exchange (ETDEWEB)

    Bacaloni, A.; Goretti, G.; Lagana, A.; Petronio, B.M.; Rotatori, M.

    1980-11-01

    The use of graphitized carbon black (GCB) to extract trace organic pollutants from water is analyzed. Adsorbent materials such as GCB or Tenax can be used to determine low concentrations of organic pollutants in water. The adsorption ability of GCB vs. that of Tenax was tested with 51 different compounds including alcohols, acids, phenols, ethers, hydrocarbons,and PCB's at concentrations ranging from 5 ppb to 200 ppb. Chlorinated pesticides were among the compounds that were entirely adsorbed. Although the adsorbent efficiences depend on the nature of other substances in the water samples, GCB proves to be better than Tenax for pesticide determinations. (6 graphs, 17 references, 4 tables)

  20. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Directory of Open Access Journals (Sweden)

    Y. Wada

    2011-12-01

    Full Text Available During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960–2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr−1 (gross/net over the period 1960–2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest

  1. Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

    Science.gov (United States)

    Wada, Y.; van Beek, L. P. H.; Bierkens, M. F. P.

    2011-12-01

    During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960-2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr-1 (gross/net) over the period 1960-2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies

  2. The role of eutrophication models in water management

    NARCIS (Netherlands)

    Molen, van der D.

    1999-01-01

    In this thesis the role of eutrophication models in water management is analysed. The thesis consists of an extended introduction followed by five Appendices with papers describing different mathematical models dealing with eutrophication in surface waters. At first systems analysis is described as

  3. TAPWAT: Definition structure and applications for modelling drinking water treatment

    NARCIS (Netherlands)

    Versteegh JFM; Gaalen FW van; Rietveld LC; Evers EG; Aldenberg TA; Cleij P; Technische Universiteit Delft; LWD

    2001-01-01

    The 'Tool for the Analysis of the Production of drinking WATer' (TAPWAT) model has been developed for describing drinking-water quality in integral studies in the context of the Environmental Policy Assessment of the RIVM. The model consists of modules that represent individual steps in a treatment

  4. The role of eutrophication models in water management

    NARCIS (Netherlands)

    Molen, van der D.

    1999-01-01

    In this thesis the role of eutrophication models in water management is analysed. The thesis consists of an extended introduction followed by five Appendices with papers describing different mathematical models dealing with eutrophication in surface waters. At first systems analysis is

  5. TAPWAT: Definition structure and applications for modelling drinking water treatment

    NARCIS (Netherlands)

    Versteegh JFM; Gaalen FW van; Rietveld LC; Evers EG; Aldenberg TA; Cleij P; Technische Universiteit Delft; LWD

    2001-01-01

    The 'Tool for the Analysis of the Production of drinking WATer' (TAPWAT) model has been developed for describing drinking-water quality in integral studies in the context of the Environmental Policy Assessment of the RIVM. The model consists of modules that represent individual steps in a treatment

  6. Integrated modeling of ozonation for optimization of drinking water treatment

    NARCIS (Netherlands)

    van der Helm, A.W.C.

    2007-01-01

    Drinking water treatment plants automation becomes more sophisticated, more on-line monitoring systems become available and integration of modeling environments with control systems becomes easier. This gives possibilities for model-based optimization. In operation of drinking water treatment plants

  7. Integrated modeling of ozonation for optimization of drinking water treatment

    NARCIS (Netherlands)

    van der Helm, A.W.C.

    2007-01-01

    Drinking water treatment plants automation becomes more sophisticated, more on-line monitoring systems become available and integration of modeling environments with control systems becomes easier. This gives possibilities for model-based optimization. In operation of drinking water treatment plants

  8. Water quality of the river yamuna in the Delhi stretch: Key determinants and management issues

    Energy Technology Data Exchange (ETDEWEB)

    Trisal, Chaman; Tabassum, Tanveera; Kumar, Ritesh [Wetlands International - South Asia, New Delhi (India)

    2008-03-15

    The assessment of water quality of the River Yamuna in the Delhi stretch was carried out by determining changes in the concentration levels of 19 physico-chemical parameters. It was observed that vegetation plays an important role in acting as a biological sink for mineral nutrients, thereby restoring the water quality. It is proposed that restoration of the inundation pattern of floodplains would greatly help in re-aeration of the overlying water and re-absorption of pollutants through mud/water exchanges. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  9. METHOD OF DETERMINING THE ORIFICE AREA OF VALVE HEAD LOCKING PAIRS OF WATER FITTINGS

    Directory of Open Access Journals (Sweden)

    Alexandre P. Svintsov

    2016-01-01

    Full Text Available One of the important tasks when designing the water fittings is to calculate the orifice area of locking pair for passing the calculated water flow at a calculated pressure. The method of determining the orifice area with smoothly changing shape based on the piecewise-element method is proposed. This method is characterized by a comparative simplicity and sufficient accuracy for engineering calculations to determine the orifice area of the disk type locking pairs for the valve head. The proposed method allows us to determine the required size of the orifice area for passing the calculated water flow and also to determine the water flow rate depending on the opening level of orifice. The authors carried out the necessary calculations and manufactured ceramic disk type locking pairs by using the proposed method. Bench tests of water fittings with valve heads those are having orifices with smoothly changing shapes (in the form of bent blob showed that water flow is changing almost in proportional to the tap opening. This method can be used not only for the designing of the water fittings and also for the shut-off valves of various purposes.

  10. Determination of four heterocyclic insecticides by ionic liquid dispersive liquid-liquid microextraction in water samples.

    Science.gov (United States)

    Liu, Yu; Zhao, Ercheng; Zhu, Wentao; Gao, Haixiang; Zhou, Zhiqiang

    2009-02-01

    A novel microextraction method termed ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) combining high-performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of insecticides in water samples. Four heterocyclic insecticides (fipronil, chlorfenapyr, buprofezin, and hexythiazox) were selected as the model compounds for validating this new method. This technique combines extraction and concentration of the analytes into one step, and the ionic liquid was used instead of a volatile organic solvent as the extraction solvent. Several important parameters influencing the IL-DLLME extraction efficiency such as the volume of extraction solvent, the type and volume of disperser solvent, extraction time, centrifugation time, salt effect as well as acid addition were investigated. Under the optimized conditions, good enrichment factors (209-276) and accepted recoveries (79-110%) were obtained for the extraction of the target analytes in water samples. The calibration curves were linear with correlation coefficient ranged from 0.9947 to 0.9973 in the concentration level of 2-100 microg/L, and the relative standard deviations (RSDs, n=5) were 4.5-10.7%. The limits of detection for the four insecticides were 0.53-1.28 microg/L at a signal-to-noise ratio (S/N) of 3.

  11. Photocatalytic degradation of hexazinone and its determination in water via UPLC-MS/MS.

    Science.gov (United States)

    Mei, Mei; Du, Zhenxia; Xu, Ruifen; Chen, Yun; Zhang, Haojie; Qu, Shuping

    2012-06-30

    Degradation of hexazinone has been investigated by means of photocatalysis of mixed-phase crystal nano-TiO(2). Influences of adsorption, amount of nano-TiO(2), pH and irradiation time on the photocatalytic process are studied. Results show that hexazinone is totally degraded within 40min of irradiation under pH neutral conditions. This compares favorably with Degussa P25 TiO(2) when conducted under the same experimental conditions. Preliminary photocatalytic kinetic information for hexazinone degradation is proposed. First order kinetics is obtained for the adsorption and photocatalytic degradation reactions, which fit the Langmuir-Hinshelwood model. A rapid, sensitive and accurate UPLC-MS/MS technique is developed and utilized to determine the level of hexazinone in water in support of the degradation kinetics study. The results indicate a limit of detection (LOD) at 0.05μg/l and the recoveries between 90.2 and 98.5% with relative standard deviations (RSD) lower than 12%. A LC-MS/MS technique is used to trace the degradation process. Complete degradation is achieved into final products including nontoxic water, carbon dioxide and urea. A probable pathway for the total photocatalytic degradation of hexazinone is proposed.

  12. Modelling Per Capita Water Demand Change to Support System Planning

    Science.gov (United States)

    Garcia, M. E.; Islam, S.

    2016-12-01

    Water utilities have a number of levers to influence customer water usage. These include levers to proactively slow demand growth over time such as building and landscape codes as well as levers to decrease demands quickly in response to water stress including price increases, education campaigns, water restrictions, and incentive programs. Even actions aimed at short term reductions can result in long term water usage declines when substantial changes are made in water efficiency, as in incentives for fixture replacement or turf removal, or usage patterns such as permanent lawn watering restrictions. Demand change is therefore linked to hydrological conditions and to the effects of past management decisions - both typically included in water supply planning models. Yet, demand is typically incorporated exogenously using scenarios or endogenously using only price, though utilities also use rules and incentives issued in response to water stress and codes specifying standards for new construction to influence water usage. Explicitly including these policy levers in planning models enables concurrent testing of infrastructure and policy strategies and illuminates interactions between the two. The City of Las Vegas is used as a case study to develop and demonstrate this modeling approach. First, a statistical analysis of system data was employed to rule out alternate hypotheses of per capita demand decrease such as changes in population density and economic structure. Next, four demand sub-models were developed including one baseline model in which demand is a function of only price. The sub-models were then calibrated and tested using monthly data from 1997 to 2012. Finally, the best performing sub-model was integrated with a full supply and demand model. The results highlight the importance of both modeling water demand dynamics endogenously and taking a broader view of the variables influencing demand change.

  13. How processing digital elevation models can affect simulated water budgets.

    Science.gov (United States)

    Kuniansky, Eve L; Lowery, Mark A; Campbell, Bruce G

    2009-01-01

    For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation of the water table used in model cells is estimated via a two-step process. First, a regression equation is developed using existing land and water table elevations from wells in the area. This equation is then used to predict the water table surface for each model cell using land surface elevation available from digital elevation models (DEM). Two methods of processing DEM for estimating the land surface for each cell are commonly used (value nearest the cell centroid or mean value in the cell). This article demonstrates how these two methods of DEM processing can affect the simulated water budget. For the example presented, approximately 20% more total flow through the aquifer system is simulated if the centroid value rather than the mean value is used. This is due to the one-third greater average ground water gradients associated with the centroid value than the mean value. The results will vary depending on the particular model area topography and cell size. The use of the mean DEM value in each model cell will result in a more conservative water budget and is more appropriate because the model cell water table value should be representative of the entire cell area, not the centroid of the model cell.

  14. Calibrating an optimal condition model for solar water disinfection in peri-urban household water treatment in Kampala, Uganda.

    Science.gov (United States)

    Okurut, Kenan; Wozei, Eleanor; Kulabako, Robinah; Nabasirye, Lillian; Kinobe, Joel

    2013-03-01

    In low income settlements where the quality of drinking water is highly contaminated due to poor hygienic practices at community and household levels, there is need for appropriate, simple, affordable and environmentally sustainable household water treatment technology. Solar water disinfection (SODIS) that utilizes both the thermal and ultra-violet effect of solar radiation to disinfect water can be used to treat small quantities of water at household level to improve its bacteriological quality for drinking purposes. This study investigated the efficacy of the SODIS treatment method in Uganda and determined the optimal condition for effective disinfection. Results of raw water samples from the study area showed deterioration in bacteriological quality of water moved from source to the household; from 3 to 36 cfu/100 mL for tap water and 75 to 126 cfu/100 mL for spring water, using thermotolerant coliforms (TTCs) as indicator microorganisms. SODIS experiments showed over 99.9% inactivation of TTCs in 6 h of exposure, with a threshold temperature of 39.5 ± 0.7°C at about 12:00 noon, in the sun during a clear sunny day. A mathematical optimal condition model for effective disinfection has been calibrated to predict the decline of the number of viable microorganisms over time.

  15. Modeling root water uptake in soils: opportunities and challenges

    Science.gov (United States)

    Javaux, Mathieu; Couvreur, Valentin; Huber, Katrin; Meunier, Félicien; Vanderborght, Jan; Vereecken, Harry

    2016-04-01

    Root water uptake modeling concepts have evolved over time. On one hand, mesoscopic models have been developed, which explicitly represent the fluxes at the soil root interfaces. On the other hand macroscopic approaches were proposed, which embedded root water uptake into a sink term in the macroscopic mass balance equation. Today, new techniques for imaging root architecture, water fluxes and soil properties open new possibilities to the understanding of water depletion in planted soils. Amongst others, architectural hydraulic root and soil models can be used to bridge the scale gap between single root and plant scales. In this talk, several new promising experimental approaches will be presented together with new models and upscaling procedures, possibly paving the way for the future models of root water uptake. Furthermore, open challenges will also be presented.

  16. Study on the holistic model for water resources system

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jianshi; WANG Zhongjing; WENG Wenbin

    2004-01-01

    Based on the Theory of Complex Adaptive System developed recently, a holistic model for water resources system is established at the basin level for analyzing water resources management and allocation of the basin. In this holistic model framework,the subsystems of the water resources system, including hydrologic components,agricultural and industrial production, human living, ecosystem and enviorenment are combined in a dynamic connection with inner variables. According to the characteristics of the holistic model framework, a nesting genetic arithmetic is employed to solve the nonlinear optimal model. The model is applied in the Yellow River basin to analyze the rational amount of diversion water for the West Line of Water Transfer Project form South China to North China and its marginal benifit.

  17. [Research on rapid determination of organic matter concentration in aquaculture water based on ultraviolet/visible spectroscopy].

    Science.gov (United States)

    Cao, Hong; Qu, Wen-Tai; Yang, Xiang-Long; Jia, Sheng-Yao; Wang, Chun-Long; Lu, Chen

    2014-11-01

    Ultraviolet/visible (UV/Vis) spectroscopy was investigated for the rapid determination of chemical oxygen demand (COD) which was an indicator to measure the concentration of organic matter in aquaculture water. A total number of 135 collected turtle breeding water samples were scanned for UV/Vis spectrum, uninformative variable elimination (UVE) and successive projections algorithm (SPA) were combined as a mixed variable selection method to perform characteristic wavelength selection from the full wavelength spectrum, 7 characteristic wavelengths were selected from full 201 UV/Vis spectral variables, which were just 3.48% number of the full range spectrum, and the calibration time and complexity of the modeling were greatly reduced. The predicted results which were obtained by using least squares-support vector machine (LS-SVM) calibration showed that the characteristic wavelengths achieved better results (0.89 for correlation coefficient (r), 15.46 mg x L(-1) for root mean square error of prediction (RMSEP)) than full wavelengths did (0.88 for r and 15.71 mg x L(-1) for RMSEP). The comprehensive results revealed that the UV/Vis characteristic wavelengths which were obtained by UVE-SPA variable selection method, combined with LS-SVM calibration could apply to the rapid and accurate determination of COD in aquaculture water. Moreover, this study laid the foundation for further implementation of online analysis of aquaculture water and rapid determination of other water quality parameters.

  18. Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate Scale Water Quality Model

    Energy Technology Data Exchange (ETDEWEB)

    Khangaonkar, Tarang; Sackmann, Brandon S.; Long, Wen; Mohamedali, Teizeen; Roberts, Mindy

    2012-10-01

    The Salish Sea, including Puget Sound, is a large estuarine system bounded by over seven thousand miles of complex shorelines, consists of several subbasins and many large inlets with distinct properties of their own. Pacific Ocean water enters Puget Sound through the Strait of Juan de Fuca at depth over the Admiralty Inlet sill. Ocean water mixed with freshwater discharges from runoff, rivers, and wastewater outfalls exits Puget Sound through the brackish surface outflow layer. Nutrient pollution is considered one of the largest threats to Puget Sound. There is considerable interest in understanding the effect of nutrient loads on the water quality and ecological health of Puget Sound in particular and the Salish Sea as a whole. The Washington State Department of Ecology (Ecology) contracted with Pacific Northwest National Laboratory (PNNL) to develop a coupled hydrodynamic and water quality model. The water quality model simulates algae growth, dissolved oxygen, (DO) and nutrient dynamics in Puget Sound to inform potential Puget Sound-wide nutrient management strategies. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or control human impacts to DO levels in the sensitive areas. The project did not include any additional data collection but instead relied on currently available information. This report describes model development effort conducted during the period 2009 to 2012 under a U.S. Environmental Protection Agency (EPA) cooperative agreement with PNNL, Ecology, and the University of Washington awarded under the National Estuary Program

  19. Determination of water-lock critical value of low-permeability sandstones based on digital core

    Directory of Open Access Journals (Sweden)

    Honglin Zhu

    2016-05-01

    Full Text Available Research and development of water lock inhibiting measures is very crucial in verifying the link mechanism between the internal factors of water lock and its extent of damage. Based on conventional water-lock physics experiments, however, only the consequence of macro water lock damage can be investigated, while the microscopic mechanism cannot be studied. In this paper, 3D digital cores of low-permeability sandstones were prepared by means of high-resolution micro-CT scan, and their equivalent pore network model was built as well. Virtual “imbibition” experiments controlled by capillary force were carried out by using pore-scale flow simulation. Then the link mechanism between the microscopic internal factors (e.g. wettability, water saturation and pore–throat structure parameters and the water-lock damage degree was discussed. It is shown that the damage degree of water lock reduces gradually as the wettability transits from water wet to gas wet. Therefore, the water lock damage can be reduced effectively and gas-well productivity can be improved so long as the capillary environment is changed from strong water wettability to weak gas wettability. The more different the initial water saturation is from the irreducible water saturation, the more serious the water lock damage is. The damage degree of water lock is in a negative correlation with the coordinate number, but a positive correlation with the pore–throat ratio. Based on the existing research results, water lock tends to form in the formations composed of medium-sized throats. It is concluded that there is a critical throat radius, at which the water lock is the most serious.

  20. Modeling of Microwave Reflection from the Surface of Water Basins with Spills of Water-Cut Oil

    Science.gov (United States)

    Krotikov, V. D.; Pelushenko, S. A.; Rakut', I. V.; Savelyev, V. Yu.

    2015-06-01

    We consider specific features of reflection of microwaves from the surface of a water basin for the two-layer model of oil spills, which are determined by a water-cut-oil film. Within the spill model, the dielectric properties of water were allowed for in accordance with the Debye theory, and the dielectric properties of the water-cut oil, in accordance with the theory developed for binary systems. The data about variations in the values of reflection coefficients depending on the frequency, viewing angle, thickness of the oil film, and moisture content in the film are obtained. The dependences of reflection coefficients on the film thickness are determined for various values of volume content of the water fraction in oil. Complex values of the dielectric permittivity of oil-water emulsions with preset volume moisture content are found. Describing the obtained dependences of the complex dielectric permittivity of the emulsion on the volume moisture content requires application of asymmetrical formulas for the mixture of polar and nonpolar fluids.

  1. Water accounting for stressed river basins based on water resources management models.

    Science.gov (United States)

    Pedro-Monzonís, María; Solera, Abel; Ferrer, Javier; Andreu, Joaquín; Estrela, Teodoro

    2016-09-15

    Water planning and the Integrated Water Resources Management (IWRM) represent the best way to help decision makers to identify and choose the most adequate alternatives among other possible ones. The System of Environmental-Economic Accounting for Water (SEEA-W) is displayed as a tool for the building of water balances in a river basin, providing a standard approach to achieve comparability of the results between different territories. The target of this paper is to present the building up of a tool that enables the combined use of hydrological models and water resources models to fill in the SEEA-W tables. At every step of the modelling chain, we are capable to build the asset accounts and the physical water supply and use tables according to SEEA-W approach along with an estimation of the water services costs. The case study is the Jucar River Basin District (RBD), located in the eastern part of the Iberian Peninsula in Spain which as in other many Mediterranean basins is currently water-stressed. To guide this work we have used PATRICAL model in combination with AQUATOOL Decision Support System (DSS). The results indicate that for the average year the total use of water in the district amounts to 15,143hm(3)/year, being the Total Water Renewable Water Resources 3909hm(3)/year. On the other hand, the water service costs in Jucar RBD amounts to 1634 million € per year at constant 2012 prices. It is noteworthy that 9% of these costs correspond to non-conventional resources, such as desalinated water, reused water and water transferred from other regions.

  2. Water equilibria and management using a two-volume model of a polymer electrolyte fuel cell

    Science.gov (United States)

    Karnik, Amey Y.; Stefanopoulou, Anna G.; Sun, Jing

    In this paper, we introduce a modified interpretation of the water activity presented in Springer et al. [T.E. Springer, T.A. Zawodzinski, S. Gottesfeld, Polymer electrolyte fuel cell model, J. Electrochem. Soc. 138 (8) (1991) 2334-2342]. The modification directly affects the membrane water transport between the anode and the cathode (two electrodes) of the polymer electrolyte membrane (PEM) fuel cell in the presence of liquid water inside the stack. The modification permits calibration of a zero-dimensional isothermal model to predict the flooding and drying conditions in the two electrodes observed at various current levels [D. Spernjak, S. Advani, A.K. Prasad, Experimental investigation of liquid water formation and transport in a transparent single-serpentine PEM fuel cell, in: Proceedings of the Fourth International Conference on Fuel Cell Science, Engineering and Technology (FUELCELL2006-97271), June 2006]. Using this model the equilibria of the lumped water mass in the two electrodes are analyzed at various flow conditions of the stack to determine stable and unstable (liquid water growth) operating conditions. Two case studies of water management through modification of cathode inlet humidification and anode water removal are then evaluated using this model. The desired anode water removal and the desired cathode inlet humidification are specified based upon (i) the water balance requirements, (ii) the desired conditions in the electrodes, and (iii) the maximum membrane transport at those conditions.

  3. Parameter selection and model research on remote sensing evaluation for nearshore water quality

    Institute of Scientific and Technical Information of China (English)

    LEI Guibin; ZHANG Ying; PAN Delu; WANG Difeng; FU Dongyang

    2016-01-01

    Using remote sensing technology for water quality evaluation is an inevitable trend in marine environmental monitoring. However, fewer categories of water quality parameters can be monitored by remote sensing technology than the 35 specified in GB3097-1997 Marine Water Quality Standard. Therefore, we considered which parameters must be selected by remote sensing and how to model for water quality evaluation using the finite parameters. In this paper, focused on Leizhou Peninsula nearshore waters, we found N, P, COD, PH and DO to be the dominant parameters of water quality by analyzing measured data. Then, mathematical statistics was used to determine that the relationship among the five parameters was COD>DO>P>N>pH. Finally, five-parameter, four-parameter and three-parameter water quality evaluation models were established and compared. The results showed that COD, DO, P and N were the necessary parameters for remote sensing evaluation of the Leizhou Peninsula nearshore water quality, and the optimal comprehensive water quality evaluation model was the four-parameter model. This work may serve as a reference for monitoring the quality of other marine waters by remote sensing.

  4. Fuzzy logic applied to the modeling of water dynamics in an Oxisol in northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Antônio Cláudio Marques Afonso

    2014-04-01

    Full Text Available Modeling of water movement in non-saturated soil usually requires a large number of parameters and variables, such as initial soil water content, saturated water content and saturated hydraulic conductivity, which can be assessed relatively easily. Dimensional flow of water in the soil is usually modeled by a nonlinear partial differential equation, known as the Richards equation. Since this equation cannot be solved analytically in certain cases, one way to approach its solution is by numerical algorithms. The success of numerical models in describing the dynamics of water in the soil is closely related to the accuracy with which the water-physical parameters are determined. That has been a big challenge in the use of numerical models because these parameters are generally difficult to determine since they present great spatial variability in the soil. Therefore, it is necessary to develop and use methods that properly incorporate the uncertainties inherent to water displacement in soils. In this paper, a model based on fuzzy logic is used as an alternative to describe water flow in the vadose zone. This fuzzy model was developed to simulate the displacement of water in a non-vegetated crop soil during the period called the emergency phase. The principle of this model consists of a Mamdani fuzzy rule-based system in which the rules are based on the moisture content of adjacent soil layers. The performances of the results modeled by the fuzzy system were evaluated by the evolution of moisture profiles over time as compared to those obtained in the field. The results obtained through use of the fuzzy model provided satisfactory reproduction of soil moisture profiles.

  5. Better Insight Into Water Resources Management With Integrated Hydrodynamic And Water Quality Models

    Science.gov (United States)

    Debele, B.; Srinivasan, R.; Parlange, J.

    2004-12-01

    Models have long been used in water resources management to guide decision making and improve understanding of the system. Numerous models of different scales -spatial and temporal - are available. Yet, very few models manage to bridge simulations of hydrological and water quality parameters from both upland watershed and riverine system. Most water quality models, such as QUAL2E and EPD-RIV1 concentrate on the riverine system while CE-QUAL-W2 and WASP models focus on larger waterbodies, such as lakes and reservoirs. On the other hand, the original SWAT model, HSPF and other upland watershed hydrological models simulate agricultural (diffuse) pollution sources with limited number of processes incorporated to handle point source pollutions that emanate from industrial sectors. Such limitations, which are common in most hydrodynamic and water quality models undermine better understanding that otherwise could be uncovered by employing integrated hydrological and water quality models for both upland watershed and riverine system. The SWAT model is a well documented and verified hydrological and water quality model that has been developed to simulate the effects of various management scenarios on the health of the environment in terms of water quantity and quality. Recently, the SWAT model has been extended to include the simulation of hydrodynamic and water quality parameters in the river system. The extended SWAT model (ESWAT) has been further extended to run using diurnally varying (hourly) weather data and produce outputs at hourly timescales. This and other improvements in the ESWAT model have been documented in the current work. Besides, the results from two case studies in Texas will be reported.

  6. Decay of Bacteroidales genetic markers in relation to traditional fecal indicators for water quality modeling of drinking water sources.

    Science.gov (United States)

    Sokolova, Ekaterina; Aström, Johan; Pettersson, Thomas J R; Bergstedt, Olof; Hermansson, Malte

    2012-01-17

    The implementation of microbial fecal source tracking (MST) methods in drinking water management is limited by the lack of knowledge on the transport and decay of host-specific genetic markers in water sources. To address these limitations, the decay and transport of human (BacH) and ruminant (BacR) fecal Bacteroidales 16S rRNA genetic markers in a drinking water source (Lake Rådasjön in Sweden) were simulated using a microbiological model coupled to a three-dimensional hydrodynamic model. The microbiological model was calibrated using data from outdoor microcosm trials performed in March, August, and November 2010 to determine the decay of BacH and BacR markers in relation to traditional fecal indicators. The microcosm trials indicated that the persistence of BacH and BacR in the microcosms was not significantly different from the persistence of traditional fecal indicators. The modeling of BacH and BacR transport within the lake illustrated that the highest levels of genetic markers at the raw water intakes were associated with human fecal sources (on-site sewers and emergency sewer overflow). This novel modeling approach improves the interpretation of MST data, especially when fecal pollution from the same host group is released into the water source from different sites in the catchment.

  7. Quantitative method to determine the regional drinking water odorant regulation goals based on odor sensitivity distribution: illustrated using 2-MIB.

    Science.gov (United States)

    Yu, Jianwei; An, Wei; Cao, Nan; Yang, Min; Gu, Junong; Zhang, Dong; Lu, Ning

    2014-07-01

    Taste and odor (T/O) in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward T/O. This study proposed a method to determine the regional drinking water odorant regulation goals (ORGs) based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisoborneol (2-MIB) by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA (flavor profile analysis) intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations.

  8. A review of hydrological/water-quality models

    Directory of Open Access Journals (Sweden)

    Liangliang GAO,Daoliang LI

    2014-12-01

    Full Text Available Water quality models are important in predicting the changes in surface water quality for environmental management. A range of water quality models are wildly used, but every model has its advantages and limitations for specific situations. The aim of this review is to provide a guide to researcher for selecting a suitable water quality model. Eight well known water quality models were selected for this review: SWAT, WASP, QUALs, MIKE 11, HSPF, CE-QUAL-W2, ELCOM-CAEDYM and EFDC. Each model is described according to its intended use, development, simulation elements, basic principles and applicability (e.g., for rivers, lakes, and reservoirs and estuaries. Currently, the most important trends for future model development are: (1 combination models─individual models cannot completely solve the complex situations so combined models are needed to obtain the most appropriate results, (2 application of artificial intelligence and mechanistic models combined with non-mechanistic models will provide more accurate results because of the realistic parameters derived from non-mechanistic models, and (3 integration with remote sensing, geographical information and global position systems (3S ─3S can solve problems requiring large amounts of data.

  9. A computerized coal-water slurry transportation model

    Energy Technology Data Exchange (ETDEWEB)

    Ljubicic, B.R.; Trostad, B. [Univ. of North Dakota, Grand Forks, ND (United States); Bukurov, Z.; Cvijanovic, P. [Univ. of Novi Sad (Yugoslavia)

    1995-12-01

    Coal-water fuel (CWF) technology has been developed to the point where full-scale commercialization is just a matter of gaining sufficient market confidence in the price stability of alternate fossil fuels. In order to generalize alternative fuel cost estimates for the desired combinations of processing and/or transportation, a great deal of flexibility is required owing to the understood lack of precision in many of the newly emerging coal technologies. Previously, decisions regarding the sequential and spatial arrangement of the various process steps were made strictly on the basis of experience, simplified analysis, and intuition. Over the last decade, computer modeling has progressed from empirically based correlation to that of intricate mechanistic analysis. Nomograms, charts, tables, and many simple rules of thumb have been made obsolete by the availability of complex computer models. Given the ability to view results graphically in real or near real time, the engineer can immediately verify, from a practical standpoint, whether the initial assumptions and inputs were indeed valid. If the feasibility of a project is being determined in the context of a lack of specific data, the ability to provide a dynamic software-based solution is crucial. Furthermore, the resulting model can be used to establish preliminary operating procedures, test control logic, and train plant/process operators. Presented in this paper is a computerized model capable of estimating the delivered cost of CWF. The model uses coal-specific values, process and transport requirements, terrain factors, and input costs to determine the final operating configuration, bill of materials, and, ultimately, the capital, operating, and unit costs.

  10. Global modelling of river water quality under climate change

    Science.gov (United States)

    van Vliet, Michelle T. H.; Franssen, Wietse H. P.; Yearsley, John R.

    2017-04-01

    Climate change will pose challenges on the quality of freshwater resources for human use and ecosystems for instance by changing the dilution capacity and by affecting the rate of chemical processes in rivers. Here we assess the impacts of climate change and induced streamflow changes on a selection of water quality parameters for river basins globally. We used the Variable Infiltration Capacity (VIC) model and a newly developed global water quality module for salinity, temperature, dissolved oxygen and biochemical oxygen demand. The modelling framework was validated using observed records of streamflow, water temperature, chloride, electrical conductivity, dissolved oxygen and biochemical oxygen demand for 1981-2010. VIC and the water quality module were then forced with an ensemble of bias-corrected General Circulation Model (GCM) output for the representative concentration pathways RCP2.6 and RCP8.5 to study water quality trends and identify critical regions (hotspots) of water quality deterioration for the 21st century.

  11. Adsoption Model of Mercury in the Water-Sediment Systems in Riam Kanan Dam, South Kalimantan

    Directory of Open Access Journals (Sweden)

    Utami Irawati

    2014-06-01

    Full Text Available The Riam Kanan  Dam reservoir is one of living source for the people of South Kalimantan and has a strategic value for their prosperity. Traditional and illegal mining activities nearby the area of this dam may cause heavy metals pollution, such as mercury (Hg in the water and sediment. This research was conducted to predict  the adsorption model of mercury (Hg in water and sediment system in Riam Kanan reservoir  Banjar regency.  The modeling was carried out by analyzing the content of mercury (Hg in the water  and sediments. The result was then plotted into Freundlich and Langmuir models. The determination coefficient for each of the models were 0.947 and 0.388 respectively. It can be concluded that the transport of mercury (Hg from water bodies  onto the sediment complies with Freundlich model.

  12. Reduction of large-scale numerical ground water flow models

    NARCIS (Netherlands)

    Vermeulen, P.T.M.; Heemink, A.W.; Testroet, C.B.M.

    2002-01-01

    Numerical models are often used for simulating ground water flow. Written in state space form, the dimension of these models is of the order of the number of model cells and can be very high (> million). As a result, these models are computationally very demanding, especially if many different scena

  13. How NaCl and water content determine water activity during ripening of Gouda cheese, and the predicted effect on inhibition of Listeria monocytogenes.

    Science.gov (United States)

    Wemmenhove, E; Wells-Bennik, M H J; Stara, A; van Hooijdonk, A C M; Zwietering, M H

    2016-07-01

    This study describes the diffusion of NaCl and water in Gouda cheese during brining and ripening. Furthermore, we established water activity as a function of the NaCl-in-moisture content in Gouda cheese during ripening. We determined NaCl content, water content, and water activity in block-type Gouda cheeses that were brined for 3.8d and foil-ripened for a period of 26 wk, and in wheel-type Gouda cheeses that were brined for 0.33, 2.1, or 8.9d and subsequently nature-ripened for a period of 26 wk. The calculated diffusion coefficients of NaCl during brining were 3.6·10(-10) m(2)s(-1) in the block-type Gouda cheeses and 3.5·10(-10) m(2)s(-1) in the wheel-type Gouda cheeses. Immediately after brining, gradients of NaCl and water were observed throughout both types of cheese. During ripening, these gradients disappeared, except for the water gradient in nature-ripened cheeses. An empirical model was derived for Gouda cheese, in which water activity is expressed as a function of the NaCl-in-moisture content, as established for different brining times, locations and ripening times. Moreover, the effect of reduced water activity on inhibition of growth of Listeria monocytogenes in Gouda cheese was calculated. In addition to the presence of lactate and a pH of 5.2 to 5.3, the reduced water activity as seen in Gouda cheese can substantially contribute to inhibition of microbial growth and even to inactivation when cheeses are brined and ripened for extended times and subjected to nature-ripening. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. GEOINFORMATION-CARTOGRAPHIC MODELING OF WATER AVAILABILITY FOR WATER SECURITY AND SUSTAINABLE DEVELOPMENT OF TERRITORIES

    Directory of Open Access Journals (Sweden)

    I. D. Rybkina

    2016-01-01

    Full Text Available The study of problem associated with water availability and its mapping is due to the need to solve urgent water problems of the Russian regions for their sustainable development. At the same time, sustainability is understood as rational use of water resources and their conservation to maintain the ecological balance of territories, and water security of regions is evaluated from the standpoint of water supply to municipalities. The shortage of water resources in Russia is perceived skeptically since our country is rich in water resources and the scarcity of fresh water threatens only a small part of its territory. However, the experts consider [Danilov-Danilyan, Galfan, 2015] that such a myopic point of view can lead in the long term to emergencies. The potential danger and risk of water use are already typical for the areas, which experience water stress. These are the territories with extremely low water availability per capita, less than 1.0-2.0 thousand m3/person/year [Shiklomanov, 2000; Danilov-Danilyan, Losev, 2006]. Geoinformation-cartographic modeling allows to differentiate the area under study according to water resource potential, to identify municipalities with low water availability and to estimate the population living in the area of potential danger and risk of water use.

  15. Reduction of Waste Water in Erhai Lake Based on MIKE21 Hydrodynamic and Water Quality Model

    Directory of Open Access Journals (Sweden)

    Changjun Zhu

    2013-01-01

    Full Text Available In order to study the ecological water environment in Erhai Lake, different monitoring sections were set to research the change of hydrodynamics and water quality. According to the measured data, MIKE21 Ecolab, the water quality simulation software developed by DHI, is applied to simulate the water quality in Erhai Lake. The hydrodynamics model coupled with water quality is established by MIKE21FM software to simulate the current situation of Erhai Lake. Then through the comparison with the monitoring data, the model parameters are calibrated and the simulation results are verified. Based on this, water quality is simulated by the two-dimensional hydrodynamics and water quality coupled model. The results indicate that the level of water quality in the north and south of lake is level III, while in the center of lake, the water quality is level II. Finally, the water environment capacity and total emmision reduction of pollutants are filtered to give some guidance for the water resources management and effective utilization in the Erhai Lake.

  16. Water quality determination by photographic analysis. [optical density and water turbidity

    Science.gov (United States)

    Klooster, S. A.; Scherz, J. P.

    1973-01-01

    Aerial reconnaissance techniques to extract water quality parameters from aerial photos are reported. The turbidity can be correlated with total suspended solids if the constituent parts of the effluent remain the same and the volumetric flow remains relatively constant. A monochromator is used for the selection of the bandwidths containing the most information. White reflectance panels are used to locate sampling points and eliminate inherent energy changes from lens flare, radial lens fall-off, and changing subject illumination. Misleading information resulting from bottom effects is avoided by the use of Secchi disc readings and proper choice of wavelength for analyzing the photos.

  17. Water's structure around hydrophobic solutes and the iceberg model.

    Science.gov (United States)

    Galamba, N

    2013-02-21

    The structure of water in the hydration shells of small hydrophobic solutes was investigated through molecular dynamics. The results show that a subset of water molecules in the first hydration shell of a nonpolar solute have a significantly enhanced tetrahedrality and a slightly larger number of hydrogen bonds, relative to the molecules in water at room temperature, consistent with the experimentally observed negative excess entropy and increased heat capacity of hydrophobic solutions at room temperature. This ordering results from the rearrangement of a small number of water molecules near the nonpolar solutes that occupy one to two vertices of the enhanced water tetrahedra. Although this structuring is not nearly like that often associated with a literal interpretation of the term "iceberg" in the Frank and Evans iceberg model, it does support a moderate interpretation of this model. Thus, the tetrahedral orientational order of this ensemble of water molecules is comparable to that of liquid water at ~10 °C, although not accompanied by the small contraction of the O-O distance observed in cold water. Further, we show that the structural changes of water in the vicinity of small nonpolar solutes cannot be inferred from the water radial distribution functions, explaining why this increased ordering is not observed through neutron diffraction experiments. The present results restore a molecular view where the slower translational and reorientational dynamics of water near hydrophobic groups has a structural equivalent resembling water at low temperatures.

  18. Revised Parameters for the AMOEBA Polarizable Atomic Multipole Water Model.

    Science.gov (United States)

    Laury, Marie L; Wang, Lee-Ping; Pande, Vijay S; Head-Gordon, Teresa; Ponder, Jay W

    2015-07-23

    A set of improved parameters for the AMOEBA polarizable atomic multipole water model is developed. An automated procedure, ForceBalance, is used to adjust model parameters to enforce agreement with ab initio-derived results for water clusters and experimental data for a variety of liquid phase properties across a broad temperature range. The values reported here for the new AMOEBA14 water model represent a substantial improvement over the previous AMOEBA03 model. The AMOEBA14 model accurately predicts the temperature of maximum density and qualitatively matches the experimental density curve across temperatures from 249 to 373 K. Excellent agreement is observed for the AMOEBA14 model in comparison to experimental properties as a function of temperature, including the second virial coefficient, enthalpy of vaporization, isothermal compressibility, thermal expansion coefficient, and dielectric constant. The viscosity, self-diffusion constant, and surface tension are also well reproduced. In comparison to high-level ab initio results for clusters of 2-20 water molecules, the AMOEBA14 model yields results similar to AMOEBA03 and the direct polarization iAMOEBA models. With advances in computing power, calibration data, and optimization techniques, we recommend the use of the AMOEBA14 water model for future studies employing a polarizable water model.

  19. Determination of Water Sensitivity Index in EstakoWest and Esan Central, Nigeria

    Directory of Open Access Journals (Sweden)

    Philipa O. Idogho

    2014-07-01

    Full Text Available As world population and industrial-agricultural outputs have increased, the use of water has accelerated. This development leads to extreme difficulty to provide sufficient safe drinking water in Etasko-West and Esan Central. Water sensitivity was measured in six major towns in Etasko-West and Esan Central. Water Measuring Indicators such as Water Poverty Index-Real Time (WPIr, Water Factor Value (WFV and Access-Demand Factor (γ were applied to generate water sensitivity iterations. The outputs of these iterations show that Irrua has the fairest water supply and distribution with WPIr, WFA and γ index value of 0.22; 0.77 and 0.76, while Auchi and Ewu experience acute water shortage with the following index values: WPIr-0.43, 0.39; WFV-0.06, 0.16; and γ-0.64, 0.6 respectively. Results of One-Sample Test and Paired Sample Statistics show that the proportion of monthly income spent on portable water is significant at 0.95 confidence interval in all towns, except Auchi. Comparative analysis indicates strong relationship (R 2=0.667 between the resources spent in procuring clean water and accessibility-demand ratio in the region. Private sector participation recorded highest investment value of 62% on water sector; government and corporate organization recorded 23% and 15% respectively. Since private sector determines the progresses of water sector, this accounts for the exorbitant tariff of 1, 500 N per m 3 in this region. It is deduced that the most significant problems faced with water accessibility-affordability are transportation, finance and power supply with computed constraint index value of 47%, 40% and 13% respectively. Finally, Etasko-West and Esan Central are highly waterstressed. Government, corporate organization and private investors need to establish technically-based measures to ensure perfect accessibility and affordability of this scarce utility.

  20. Modelling heterogeneous interfaces for solar water splitting

    Science.gov (United States)

    Pham, Tuan Anh; Ping, Yuan; Galli, Giulia

    2017-04-01

    The generation of hydrogen from water and sunlight offers a promising approach for producing scalable and sustainable carbon-free energy. The key of a successful solar-to-fuel technology is the design of efficient, long-lasting and low-cost photoelectrochemical cells, which are responsible for absorbing sunlight and driving water splitting reactions. To this end, a detailed understanding and control of heterogeneous interfaces between photoabsorbers, electrolytes and catalysts present in photoelectrochemical cells is essential. Here we review recent progress and open challenges in predicting physicochemical properties of heterogeneous interfaces for solar water splitting applications using first-principles-based approaches, and highlights the key role of these calculations in interpreting increasingly complex experiments.

  1. Modelling heterogeneous interfaces for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Tuan Anh; Ping, Yuan; Galli, Giulia

    2017-01-09

    The generation of hydrogen from water and sunlight others a promising approach for producing scalable and sustainable carbon-free energy. The key of a successful solar-to-fuel technology is the design of efficient, long-lasting and low-cost photoelectrochemical cells, which are responsible for absorbing sunlight and driving water splitting reactions. To this end, a detailed understanding and control of heterogeneous interfaces between photoabsorbers, electrolytes and catalysts present in photoelectrochemical cells is essential. Here we review recent progress and open challenges in predicting physicochemical properties of heterogeneous interfaces for solar water splitting applications using first-principles-based approaches, and highlights the key role of these calculations in interpreting increasingly complex experiments.

  2. Moisture Absorption Model of Composites Considering Water Temperature Effect

    Directory of Open Access Journals (Sweden)

    HUI Li

    2016-11-01

    Full Text Available The influence of water temperature on composite moisture absorption parameters was investigated in temperature-controlled water bath. Experiments of carbon fiber/bismaleimide resin composites immersed in water of 60℃, 70℃and 80℃ were developed respectively. According to the moisture content-time curves obtained from the experimental results, the diffusion coefficient and the balanced moisture content of the composites immersed in different water temperature could be calculated. What's more, the effect of water temperature on the diffusion coefficient and the balanced moisture content were discussed too. According to the Arrhenius equation and the law of Fick, a moisture absorption model was proposed to simulate the hygroscopic behaviour of the composite laminates immersed in different water temperature which can predict the absorption rate of water of the composites immersed in distilled water of 95℃ at any time precisely and can calculate how long it will take to reach the specific absorption rate.

  3. DETERMINING INDICATORS OF URBAN HOUSEHOLD WATER CONSUMPTION THROUGH MULTIVARIATE STATISTICAL TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Gledsneli Maria Lima Lins

    2010-12-01

    Full Text Available Water has a decisive influence on populations’ life quality – specifically in areas like urban supply, drainage, and effluents treatment – due to its sound impact over public health. Water rational use constitutes the greatest challenge faced by water demand management, mainly with regard to urban household water consumption. This makes it important to develop researches to assist water managers and public policy-makers in planning and formulating water demand measures which may allow urban water rational use to be met. This work utilized the multivariate techniques Factor Analysis and Multiple Linear Regression Analysis – in order to determine the participation level of socioeconomic and climatic variables in monthly urban household consumption changes – applying them to two districts of Campina Grande city (State of Paraíba, Brazil. The districts were chosen based on socioeconomic criterion (income level so as to evaluate their water consumer’s behavior. A 9-year monthly data series (from year 2000 up to 2008 was utilized, comprising family income, water tariff, and quantity of household connections (economies – as socioeconomic variables – and average temperature and precipitation, as climatic variables. For both the selected districts of Campina Grande city, the obtained results point out the variables “water tariff” and “family income” as indicators of these district’s household consumption.

  4. Determination of a Reasonable Percentage for Ecological Water-Use in the Haihe River Basin, China

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; FENG Hua-Li; ZHAN Che-Sheng; NIU Cun-Wen

    2006-01-01

    An investigation was conducted to study problems of determining a reasonable percentage for ecological water-use in the Haihe River Basin of China. Three key aspects for the ecological water requirement (EWR) were analyzed, involving i) the EWR for river system, ii) the EWR for wetlands and lakes, and iii) the EWR for discharge into the sea to maintain the estuary ecological balance of the Haihe River. The Montana method and related water level-flow relationships, and the statistic approach based on hydrological records were applied to estimate different components of EWR. The results showed that the total ecological water demand in the region was about 3.47-14.56 billion m3. Considering flow regime change and uncertainty, the ecological water demand could be estimated by the hydrological frequency approach. Preliminary analysis showed that for different annual runoff under the frequencies of 20%, 50%, 75% and 95%, the ecological water demand approached 12%-50%, 18%-74%, 24%-103%, 35%-148% and 16%-66%, respectively. By further analysis to balance ecological water-use and socioeconomic water-use, the rational percentage of ecological water-use was estimated as 35%-74%, that provides useful information to judge whether the allocation of water resources is reasonable, and was proved to be satisfactory by comparing with the practical condition.

  5. Rapid determination of octanol-water partition coefficient using vortex-assisted liquid-liquid microextraction.

    Science.gov (United States)

    Román, Iván P; Mastromichali, Anna; Tyrovola, Konstantina; Canals, Antonio; Psillakis, Elefteria

    2014-02-21

    Vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography (HPLC) is proposed here for the rapid determination of octanol-water partitioning coefficients (Kow). VALLME uses vortex agitation, a mild emulsification procedure, to disperse microvolumes of octanol in the aqueous phase thus increasing the interfacial contact area and ensuring faster partitioning rates. With VALLME, 2min were enough to achieve equilibrium conditions between the octanolic and aqueous phases. Upon equilibration, separation was achieved using centrifugation and the octanolic microdrop was collected and analyzed in a HPLC system. Six model compounds with logKow values ranging between ∼0.5 and 3.5 were used during the present investigations. The proposed method produced logKow values that were consistent with previously published values and the recorded uncertainty was well within the acceptable log unit range. Overall, the key features of the proposed Kow determination procedure comprised speed, reliability, simplicity, low cost and minimal solvent consumption.

  6. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  7. Models of Fate and Transport of Pollutants in Surface Waters

    Science.gov (United States)

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  8. Determination of air-loop volume and radon partition coefficient for measuring radon in water sample.

    Science.gov (United States)

    Lee, Kil Yong; Burnett, William C

    A simple method for the direct determination of the air-loop volume in a RAD7 system as well as the radon partition coefficient was developed allowing for an accurate measurement of the radon activity in any type of water. The air-loop volume may be measured directly using an external radon source and an empty bottle with a precisely measured volume. The partition coefficient and activity of radon in the water sample may then be determined via the RAD7 using the determined air-loop volume. Activity ratios instead of absolute activities were used to measure the air-loop volume and the radon partition coefficient. In order to verify this approach, we measured the radon partition coefficient in deionized water in the temperature range of 10-30 °C and compared the values to those calculated from the well-known Weigel equation. The results were within 5 % variance throughout the temperature range. We also applied the approach for measurement of the radon partition coefficient in synthetic saline water (0-75 ppt salinity) as well as tap water. The radon activity of the tap water sample was determined by this method as well as the standard RAD-H2O and BigBottle RAD-H2O. The results have shown good agreement between this method and the standard methods.

  9. Quantitative Determination of Arsenic in Bottled Drinking Water Using Atomic Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Maria Guţu Claudia

    2013-10-01

    Full Text Available Background: Many studies have been performed in the past few years, to determine arsenic speciation in drinking water, food chain and environment, arsenic being a well-recognized carcinogenic and toxic agent mainly in its inorganic species. The instrumental techniques used for arsenic determination, such as hydride generation atomic absorption spectrometry (HGAAS, graphite furnace atomic absorption spectrometry (GFAAS and inductively coupled plasma mass spectrometry (ICP-MS, can provide a great sensitivity only on the total amount. Objective: The aim of this study was to develop a simple and rapid method and to analyze the concentration of total inorganic arsenic in bottled drinking water. Methods: Total arsenic was determined in samples from six different types of commercially available bottled drinking water using atomic absorption spectrometry with electrothermal or hydride generation vaporisation. All drinking water samples were acidified with 0.1M nitric acid to match the acidity of the standards. Results: The method was linear within the studied range (1-5 μg/L, R = 0.9943. The quantification limits for arsenic determination were 0.48 μg/L (HGAAS and 0.03 μg/L (GFAAS. The evaluated arsenic content in drinking water was within the accepted limits provided by law. Conclusions: A simple and sensitive method for the quantification of arsenic in drinking water using atomic absorbtion spectroscopy was described, which can be further used in toxicological studies. As an additional advantage, the system is very fast, efficient and environmental friendly

  10. Water resources management in karst aquifers - concepts and modeling approaches

    Science.gov (United States)

    Sauter, M.; Schmidt, S.; Abusaada, M.; Reimann, T.; Liedl, R.; Kordilla, J.; Geyer, T.

    2011-12-01

    Water resources management schemes generally imply the availability of a spectrum of various sources of water with a variability of quantity and quality in space and time, and the availability and suitability of storage facilities to cover various demands of water consumers on quantity and quality. Aquifers are generally regarded as suitable reservoirs since large volumes of water can be stored in the subsurface, water is protected from contamination and evaporation and the underground passage assists in the removal of at least some groundwater contaminants. Favorable aquifer properties include high vertical hydraulic conductivities for infiltration, large storage coefficients and not too large hydraulic gradients / conductivities. The latter factors determine the degree of discharge, i.e. loss of groundwater. Considering the above criteria, fractured and karstified aquifers appear to not really fulfill the respective conditions for storage reservoirs. Although infiltration capacity is relatively high, due to low storativity and high hydraulic conductivities, the small quantity of water stored is rapidly discharged. However, for a number of specific conditions, even karst aquifers are suitable for groundwater management schemes. They can be subdivided into active and passive management strategies. Active management options include strategies such as overpumping, i.e. the depletion of the karst water resources below the spring outflow level, the construction of subsurface dams to prevent rapid discharge. Passive management options include the optimal use of the discharging groundwater under natural discharge conditions. System models that include the superposition of the effect of the different compartments soil zone, epikarst, vadose and phreatic zone assist in the optimal usage of the available groundwater resources, while taking into account the different water reservoirs. The elaboration and implementation of groundwater protection schemes employing well

  11. Determination of 14 nitrosamines at nanogram per liter levels in drinking water.

    Science.gov (United States)

    Qian, Yichao; Wu, Minghuo; Wang, Wei; Chen, Beibei; Zheng, Hao; Krasner, Stuart W; Hrudey, Steve E; Li, Xing-Fang

    2015-01-20

    N-Nitrosamines, probable human carcinogens, are a group of disinfection byproducts under consideration for drinking water regulation. Currently, no method can determine trace levels of alkyl and tobacco-specific nitrosamines (TSNAs) of varying physical and chemical properties in water by a single analysis. To tackle this difficulty, we developed a single solid-phase extraction (SPE) method with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the determination of 14 nitrosamines of health concern with widely differing properties. We made a cartridge composed of a vinyl/divinylbenzene polymer that efficiently concentrated the 14 nitrosamines in 100 mL of water (in contrast to 500 mL in other methods). This single SPE-HPLC-MS/MS technique provided calculated method detection limits of 0.01-2.7 ng/L and recoveries of 53-93% for the 14 nitrosamines. We have successfully demonstrated that this method can determine the presence or absence of the 14 nitrosamines in drinking water systems (eight were evaluated in Canada and the U.S.), with occurrence similar to that in other surveys. N-Nitrosodimethylamine (NDMA), N-nitrosodiphenylamine, and the TSNA 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol were identified and quantified in authentic drinking water. Formation potential (FP) tests demonstrated that NDMA and TSNA precursors were present in (1) water samples in which tobacco was leached and (2) wastewater-impacted drinking water. Our results showed that prechlorination or ozonation destroyed most of the nitrosamine precursors in water. Our new single method determination of alkylnitrosamines and TSNAs significantly reduced the time and resource demands of analysis and will enable other studies to more efficiently study precursor sources, formation mechanisms, and removal techniques. It will be useful for human exposure and health risk assessments of nitrosamines in drinking water.

  12. Saline Water Irrigation Scheduling Through a Crop-Water-Salinity Production Function and a Soil-Water-Salinity Dynamic Model

    Institute of Scientific and Technical Information of China (English)

    WANG Yang-Ren; KANG Shao-Zhong; LI Fu-heng; ZHANG Lu; ZHANG Jian-Hua

    2007-01-01

    Using a crop-water-salinity production function and a soil-water-salinity dynamic model, optimal irrigation scheduling was developed to maximize net return per irrigated area. Plot and field experiments were used to obtain the crop water sensitivity index, the salinity sensitivity index, and other parameters. Using data collected during 35 years to calculate the 10-day mean precipitation and evaporation, the variation in soil salinity concentrations and in the yields of winter wheat and cotton were simulated for 49 irrigation scheduling that were combined from 7 irrigation schemes over 3 irrigation dates and 7 salinity concentrations of saline irrigation water (fresh water and 6 levels of saline water). Comparison of predicted results with irrigation data obtained from a large area of the field showed that the model was valid and reliable. Based on the analysis of the investment cost of the irrigation that employed deep tube wells or shallow tube wells, a saline water irrigation schedule and a corresponding strategy for groundwater development and utilization were proposed. For wheat or cotton, if the salinity concentration was higher than 7.0 g L-1 in groundwater, irrigation was needed with only fresh water; if about 5.0 g L-1, irrigation was required twice with fresh water and once with saline water; and if not higher than 3.0 g L-1, irrigation could be solely with saline water.

  13. The relative importance of road density and physical watershed features in determining coastal marsh water quality in Georgian Bay.

    Science.gov (United States)

    Decatanzaro, Rachel; Cvetkovic, Maja; Chow-Fraser, Patricia

    2009-09-01

    We used a GIS-based approach to examine the influence of road density and physical watershed features (watershed size, wetland cover, and bedrock type) on water quality in coastal marshes of Georgian Bay, Ontario. We created a GIS that included landscape information and water-quality data from a 9-year synoptic survey of 105 coastal marshes covering 28 quaternary watersheds. Multiple regressions and partial correlations were used to discern confounding effects of human-induced (road density) versus natural physical watershed determinants of water quality. Road density was the dominant factor influencing many water quality variables, showing positive correlations with specific conductivity (COND), total suspended solids (TSS), and inorganic suspended solids (ISS) and a negative correlation with overall Water Quality Index scores. Road density also showed positive correlations with total nitrate nitrogen (TNN) and total phosphorus (TP). By comparison, larger watershed area was the main factor leading to elevated TP concentrations. The proportion of the watershed occupied by wetlands explained the largest amount of variation in TNN concentrations (negative correlation) and was also negatively correlated with COND and positively correlated with TSS and ISS when we controlled for road density. Bedrock type did not have a significant effect in any of the models. Our findings suggest that road density is currently the overriding factor governing water quality of coastal marshes in Georgian Bay during the summer low-flow period. We recommend that natural variation in physical watershed characteristics be considered when developing water quality standards and management practices for freshwater coastal areas.

  14. Modeling shallow-water hydrodynamics: Rotations, rips, and rivers

    Science.gov (United States)

    Long, Joseph W.

    for alongshore uniform beaches. Through comparisons with remote sensing observations, the model proves it is capable of predicting rip currents when they are observed. Analysis suggests that the direction of the offshore wave spectra will dictate when and where rip currents will appear. We also find that for bi-modal offshore spectra, the relative amount of energy in each spectral mode is a better predictor of rip current development than the peak spectral characteristics. Finally, some preliminary work to estimate water depths from the combination of hydrodynamic models and available data is also presented. We focus this work in a river meander for our initial tests. A simple analytical model shows skill in predicting the water depth at only one of the two river meanders considered. This discrepancy appears to be related to river curvature and as curvature weakens, the model accuracy decreases. This is hypothesized to be the result of dispersive mixing which is not accounted for in this simple model but confirmation is still required. At the same time, we perform simulations within a river meander to determine the efficacy of using coastal hydrodynamic models in riverine environments where the principles governing the flow are the same. Our initial tests of the Regional Ocean Modeling System (ROMS) suggests that it is able to reproduce the flow through a river meander which opens the door to developing one model that can simulate conditions from upland rivers out to the continental shelf.

  15. Predictors of Drinking Water Boiling and Bottled Water Consumption in Rural China: A Hierarchical Modeling Approach.

    Science.gov (United States)

    Cohen, Alasdair; Zhang, Qi; Luo, Qing; Tao, Yong; Colford, John M; Ray, Isha

    2017-06-20

    Approximately two billion people drink unsafe water. Boiling is the most commonly used household water treatment (HWT) method globally and in China. HWT can make water safer, but sustained adoption is rare and bottled water consumption is growing. To successfully promote HWT, an understanding of associated socioeconomic factors is critical. We collected survey data and water samples from 450 rural households in Guangxi Province, China. Covariates were grouped into blocks to hierarchically construct modified Poisson models and estimate risk ratios (RR) associated with boiling methods, bottled water, and untreated water. Female-headed households were most likely to boil (RR = 1.36, p boiled. Our findings show that boiling is not an undifferentiated practice, but one with different methods of varying effectiveness, environmental impact, and adoption across socioeconomic strata. Our results can inform programs to promote safer and more efficient boiling using electric kettles, and suggest that if rural China's economy continues to grow then bottled water use will increase.

  16. Modelling water hammer in viscoelastic pipelines: short brief

    Science.gov (United States)

    Urbanowicz, K.; Firkowski, M.; Zarzycki, Z.

    2016-10-01

    The model of water hammer in viscoelastic pipelines is analyzed. An appropriate mathematical model of water hammer in polymer pipelines is presented. An additional term has been added to continuity equation to describe the retarded deformation of the pipe wall. The mechanical behavior of viscoelastic material is described by generalized Kelvin-Voigt model. The comparison of numerical simulation and experimental data from well known papers is presented. Short discussion about obtained results are given.

  17. An Integrated Model for a Water Leasing System on the Middle Rio Grand, New Mexico

    Science.gov (United States)

    Brookshire, D. S.; Coursey, D. L.; Tidwell, V. C.; Broadbent, C. D.

    2006-12-01

    Since 1950 demand for water has more than doubled in the United States. Virtually all water supplies are allocated, leading to the question, where will water come from? The concept of water leasing has gained considerable attention as a volunteer, market-mediated system for transferring water between competing uses. For a water leasing system to be truly effective, detailed knowledge of the available water supply and the factors that affect water demand is critical. Improving understating of the factors that determine residential, industrial, and agricultural demand for water using experimental economics and then integrating with a hydrological model will allow for better understanding of market-based mechanisms potential to allocate water resources effectively. Currently we have three case studies underway, a generalized water leasing system on the Middle Rio Grande, a sophisticated farmer decision process and a study in the Mimbres basin in southern New Mexico. The developed market model utilizes an open market trading system known as a double auction, where buyers and sellers declare their bids and offers to the market. The developed hydrological model utilizes the Upper Rio Grande Water Operations Model (URGWOM) system structure and data for the generalized water leasing system and the farmer decision process, with a different hydrological model being developed for the Mimbres basin. A key coupling between the hydrologic and market models involves tracking the difference in river losses for trades that move water up or down the river. In the experiments the hydrological model runs before the market-trading period to establish water rights, the trading period occurs and the hydrological model then runs a second time to report flows to each reach of the river. Participants in the experiment represent the interests of specific users, including farmers, Native American interests, urban interests and environmental interests. Participants in the experiments are

  18. The 3D simulation and optimized management model of groundwater systems based on ecoenvironmental water demand

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater's economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da'an in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.

  19. Determination of trace metals in drinking water in Irbid City-Northern Jordan.

    Science.gov (United States)

    Alomary, Ahmed

    2013-02-01

    Drinking water samples from Irbid, the second populated city in Jordan were analyzed for trace metals (As, Ba, Cd, Pb, Cr, Cu, Fe, Zn, Mn, Ni, and Se) content. The study was undertaken to determine if the metal concentrations were within the national and international guidelines. A total of 90 drinking water samples were collected from Al-Yarmouk University area. The samples were collected from three different water types: tap water (TW), home-purified water (HPW), and plant-purified water (PPW). All the samples were analyzed for trace metals using an inductively coupled plasma-optical emission spectrometry. All the samples analyzed were within the United States Environmental Protection Agency admissible pH limit (6.5-8.5). The results showed that concentrations of the trace metals vary significantly between the three drinking water types. The results showed that HPW samples have the lowest level of trace metals and the concentrations of some essential trace metals in these samples are less than the recommended amounts. Slight differences in the metal contents were found between HPW samples, little differences between PPW samples; however, significant differences were found between TW samples. Although some TW samples showed high levels of trace metals, however, the mean level of most elements determined in the samples were well within the Jordanian standards as well as the World Health Organization standards for drinking water.

  20. Determination of Water Sorption in Freestanding Epoxy Film by Capacitance Method Using EIS

    Institute of Scientific and Technical Information of China (English)

    Yinghua WEI; Lixin ZHANG; Wei KE

    2006-01-01

    Electrochemical impedance spectra (EIS) technique was adopted to evaluate the water sorption behaviour of an epoxy freestanding film in a 0.5 mol/L sodium chloride solution at 20C. The methods for obtaining the capacitance data from ElS data were compared. The Brasher-Kingsbury (BK) and corresponding modified version (Modi-BK) models were used to calculate the water uptake in film and the gravimetric results were presented for comparisons. According to the discussion of the discrepancy of water content in film obtained from two models, a new method was proposed to indicate the organic film structure.

  1. Lattice Model for water-solute mixtures

    OpenAIRE

    Furlan, A. P.; Almarza, N. G.; M. C. Barbosa

    2016-01-01

    A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophilic, inert and hydrophobic interactions. Extensive Monte Carlo simulations were carried out and the behavior of pure components and the excess proper...

  2. The determination of the most applicable PWV model for Turkey

    Science.gov (United States)

    Deniz, Ilke; Gurbuz, Gokhan; Mekik, Cetin

    2016-07-01

    Water vapor is a key component for modelling atmosphere and climate studies. Moreover, long-term water vapor changes can be an independent source for detecting climate changes. Since Global Navigation Satellite Systems (GNSS) use microwaves passing through the atmosphere, atmospheric effects are modeled with high accuracy. Tropospheric effects on GNSS signals are estimated with total zenith delay parameter (ZTD) which is the sum of hydrostatic (ZHD) and wet zenith delay (ZWD). The first component can be obtained from meteorological observations with high accuracy; the second component, however, can be computed by subtracting ZHD from ZTD (ZWD=ZTD-ZHD). Afterwards, the weighted mean temperature (Tm) or the conversion factor (Q) is used for the conversion between the precipitable water vapor (PWV) and ZWD. The parameters Tm and Q are derived from the analysis of radiosonde stations' profile observations. Numerous Q and Tm models have been developed for each radiosonde station, radiosonde station group, countries and global fields such as Bevis Tm model and Emardson and Derks' Q models. So, PWV models (Tm and Q models) applied for Turkey have been developed using a year of radiosonde data (2011) from 8 radiosonde stations. In this study the models developed are tested by comparing PWVGNSS computed applying Tm and Q models to the ZTD estimates derived by Bernese and GAMIT/GLOBK software at GNSS stations established at Istanbul and Ankara with those from the collocated radiosonde stations (PWVRS) from October 2013 to December 2014 with the data obtained from a project (no 112Y350) supported by the Scientific and Technological Research Council of Turkey (TUBITAK). The comparison results show that PWVGNSS and PWVRS are in high correlation (86 % for Ankara and 90% for Istanbul). Thus, the most applicable model for Turkey and the accuracy of GNSS meteorology are investigated. In addition, Tm model was applied to the ZTD estimates of 20 TUSAGA-Active (CORS-TR) stations in

  3. Business model innovation in the water sector in developing countries.

    Science.gov (United States)

    Gebauer, Heiko; Saul, Caroline Jennings

    2014-08-01

    Various technologies have been deployed in household devices or micro-water treatment plants for mitigating fluoride and arsenic, and thereby provide safe and affordable drinking water in low-income countries. While the technologies have improved considerably, organizations still face challenges in making them financially sustainable. Financial sustainability questions the business models behind these water technologies. This article makes three contributions to business models in the context of fluoride and arsenic mitigation. Firstly, we describe four business models: A) low-value devices given away to people living in extreme poverty, B) high-value devices sold to low-income customers, C) communities as beneficiaries of micro-water treatment plants and D) entrepreneurs as franchisees for selling water services and highlight the emergence of hybrid business models. Secondly, we show current business model innovations such as cost transparency & cost reductions, secured & extended water payments, business diversification and distribution channels. Thirdly, we describe skills and competencies as part of capacity building for creating even more business model innovations. Together, these three contributions will create more awareness of the role of business models in scaling-up water treatment technologies. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Household water use and conservation models using Monte Carlo techniques

    Science.gov (United States)

    Cahill, R.; Lund, J. R.; DeOreo, B.; Medellín-Azuara, J.

    2013-10-01

    The increased availability of end use measurement studies allows for mechanistic and detailed approaches to estimating household water demand and conservation potential. This study simulates water use in a single-family residential neighborhood using end-water-use parameter probability distributions generated from Monte Carlo sampling. This model represents existing water use conditions in 2010 and is calibrated to 2006-2011 metered data. A two-stage mixed integer optimization model is then developed to estimate the least-cost combination of long- and short-term conservation actions for each household. This least-cost conservation model provides an estimate of the upper bound of reasonable conservation potential for varying pricing and rebate conditions. The models were adapted from previous work in Jordan and are applied to a neighborhood in San Ramon, California in the eastern San Francisco Bay Area. The existing conditions model produces seasonal use results very close to the metered data. The least-cost conservation model suggests clothes washer rebates are among most cost-effective rebate programs for indoor uses. Retrofit of faucets and toilets is also cost-effective and holds the highest potential for water savings from indoor uses. This mechanistic modeling approach can improve understanding of water demand and estimate cost-effectiveness of water conservation programs.

  5. Mathematical Model of the Geothermal Water Resources in the South Hot Spring System in Chongqing

    Institute of Scientific and Technical Information of China (English)

    Liu Dongyan; Luo Yunju; Liu Xinrong

    2005-01-01

    The geothermal waters of south hot spring, small hot spring and Qiaokouba in Chongqing, are all part of the south hot spring geothermal water system. Exploitation has caused a decline in the water levels of the south and small hot springs, which have not flowed naturally for 15 years. Now, bores pump geothermal water to the springs. If the water level drops below the elevation of the rivers, river-water will replenish the geothermal water, destroying this resource. It is therefore an urgent task to model the geothermal water system, to enable sustainable development and continued use of the geothermal water in Qiaokouba. A numerical simulation of the geothermal water system was adopted and a quantitative study on the planning scheme was carried out. A mathematical model was set up to simulate the whole geothermal water system, based on data from the research sites. The model determined the maximum sustainable water yield in Qiaokouba and the two hot springs, and the south hot spring and small hot spring sustainable yields are 1 100 m3/d and 700 m3/d from 2006 to 2010, 1 300 m3/d and 1 000 m3/d from 2011 to 2015, and 1 500 m3/d and 1 200 m3/d from 2016 to 2036. The maximum exploitable yield is 3 300 m3/d from 2006 to 2036 in Qiaokouba. The model supplies a basis to adequately exploit and effectively protect the geothermal water resources, and to continue to develop the geothermal water as a tourist attraction in Chongqing.

  6. Molecular dynamics simulations of water within models of ion channels.

    Science.gov (United States)

    Breed, J; Sankararamakrishnan, R; Kerr, I D; Sansom, M S

    1996-04-01

    The transbilayer pores formed by ion channel proteins contain extended columns of water molecules. The dynamic properties of such waters have been suggested to differ from those of water in its bulk state. Molecular dynamics simulations of ion channel models solvated within and at the mouths of their pores are used to investigate the dynamics and structure of intra-pore water. Three classes of channel model are investigated: a) parallel bundles of hydrophobic (Ala20) alpha-helices; b) eight-stranded hydrophobic (Ala10) antiparallel beta-barrels; and c) parallel bundles of amphipathic alpha-helices (namely, delta-toxin, alamethicin, and nicotinic acetylcholine receptor M2 helix). The self-diffusion coefficients of water molecules within the pores are reduced significantly relative to bulk water in all of the models. Water rotational reorientation rates are also reduced within the pores, particularly in those pores formed by alpha-helix bundles. In the narrowest pore (that of the Ala20 pentameric helix bundle) self-diffusion coefficients and reorientation rates of intra-pore waters are reduced by approximately an order of magnitude relative to bulk solvent. In Ala20 helix bundles the water dipoles orient antiparallel to the helix dipoles. Such dipole/dipole interaction between water and pore may explain how water-filled ion channels may be formed by hydrophobic helices. In the bundles of amphipathic helices the orientation of water dipoles is modulated by the presence of charged side chains. No preferential orientation of water dipoles relative to the pore axis is observed in the hydrophobic beta-barrel models.

  7. An Integrated Risk Management Model for Source Water Protection Areas

    Directory of Open Access Journals (Sweden)

    Shang-Lien Lo

    2012-10-01

    Full Text Available Watersheds are recognized as the most effective management unit for the protection of water resources. For surface water supplies that use water from upstream watersheds, evaluating threats to water quality and implementing a watershed management plan are crucial for the maintenance of drinking water safe for humans. The aim of this article is to establish a risk assessment model that provides basic information for identifying critical pollutants and areas at high risk for degraded water quality. In this study, a quantitative risk model that uses hazard quotients for each water quality parameter was combined with a qualitative risk model that uses the relative risk level of potential pollution events in order to characterize the current condition and potential risk of watersheds providing drinking water. In a case study of Taipei Source Water Area in northern Taiwan, total coliforms and total phosphorus were the top two pollutants of concern. Intensive tea-growing and recreational activities around the riparian zone may contribute the greatest pollution to the watershed. Our risk assessment tool may be enhanced by developing, recording, and updating information on pollution sources in the water supply watersheds. Moreover, management authorities could use the resultant information to create watershed risk management plans.

  8. An integrated risk management model for source water protection areas.

    Science.gov (United States)

    Chiueh, Pei-Te; Shang, Wei-Ting; Lo, Shang-Lien

    2012-10-17

    Watersheds are recognized as the most effective management unit for the protection of water resources. For surface water supplies that use water from upstream watersheds, evaluating threats to water quality and implementing a watershed management plan are crucial for the maintenance of drinking water safe for humans. The aim of this article is to establish a risk assessment model that provides basic information for identifying critical pollutants and areas at high risk for degraded water quality. In this study, a quantitative risk model that uses hazard quotients for each water quality parameter was combined with a qualitative risk model that uses the relative risk level of potential pollution events in order to characterize the current condition and potential risk of watersheds providing drinking water. In a case study of Taipei Source Water Area in northern Taiwan, total coliforms and total phosphorus were the top two pollutants of concern. Intensive tea-growing and recreational activities around the riparian zone may contribute the greatest pollution to the watershed. Our risk assessment tool may be enhanced by developing, recording, and updating information on pollution sources in the water supply watersheds. Moreover, management authorities could use the resultant information to create watershed risk management plans.

  9. Water-resources optimization model for Santa Barbara, California

    Science.gov (United States)

    Nishikawa, T.

    1998-01-01

    A simulation-optimization model has been developed for the optimal management of the city of Santa Barbara's water resources during a drought. The model, which links groundwater simulation with linear programming, has a planning horizon of 5 years. The objective is to minimize the cost of water supply subject to: water demand constraints, hydraulic head constraints to control seawater intrusion, and water capacity constraints. The decision variables are montly water deliveries from surface water and groundwater. The state variables are hydraulic heads. The drought of 1947-51 is the city's worst drought on record, and simulated surface-water supplies for this period were used as a basis for testing optimal management of current water resources under drought conditions. The simulation-optimization model was applied using three reservoir operation rules. In addition, the model's sensitivity to demand, carry over [the storage of water in one year for use in the later year(s)], head constraints, and capacity constraints was tested.

  10. Determination of Thermal Properties of Fresh Water and Sea Water Ice using Multiphysics Analysis

    OpenAIRE

    Rashid, T.; KHAWAJA, H.; K Edvardsen

    2016-01-01

    Publisher's version, source: http://dx.doi.org/10.21152/1750-9548.10.3.277. This paper presents a methodology to determine the thermal conductivity of ice using multiphysics analysis. This methodology used a combination of both experimentation and numerical simulation. In the experimental work, an ice block is observed using an infrared camera. The results reveal the variation in temperature over the surface. These results are dependent on two primary heat transfer parameters, namely, cond...

  11. An Econometric Model for Water Sector in Jordan

    Directory of Open Access Journals (Sweden)

    Mohammed I.  Shahateet

    2008-01-01

    Full Text Available Problem statement: This study argued that there is an economic approach to reduce water problems faced by Jordan. The study took into consideration the increasing population size, the declining rainfall, a deepening shortage of supply and increasing demand for water, the production of agricultural and industrial sectors, price of unit exports, and lack of financial resources. Approach: The framework for a tool which takes into consideration the links between economic growth and the availability of water was developed in this study, in the form of a dynamic simulation econometric model. The model served as a quantitative tool to evaluate the water policy measures and forecast the effect of future policy variables on the water status in Jordan. Results: Agricultural, industrial and other types of production are affected by water uses which in turn are influenced by production and other socioeconomic variables, including population size, the extent of production market, and the size of linkage effects working through certain increases in water consumption. The results also showed the model can be used to solve key issues related to the formulation and implementation of water policy. They also identified lessons for water management policy within a broad socio-economic perspective. Conclusions: First, with regard to production sector, a major effect can be attributed to the supply of water. Second, gross domestic products of agricultural, industrial and other sectors were found to be highly significant factors in influencing the supply of water. Finally, priorities for making the most of Jordan's water resources should be given to options affecting water-supply strategy which relates the supply of water to the level of production.

  12. The effects of replacing the water model while decoupling water-water and water-solute interactions on computed properties of simple salts

    Science.gov (United States)

    Li, Jicun; Wang, Feng

    2016-07-01

    The effects of decoupling the water-water and water-solute interactions are studied with selected mono-valent ions as the solute. Using the ion-water cross terms developed for the BLYPSP-4F water model, we replaced the water potential with WAIL, TIP4P, and TIP3P without changing the ion-water parameters. When the adaptive force matching (AFM) derived BLYPSP-4F model is replaced by the other AFM derived WAIL model, the difference in ion properties, such as hydration free energies, radial distribution functions, relative diffusion constants, is negligible, demonstrating the feasibility for combining AFM parameters from different sources. Interestingly, when the AFM-derived ion-water cross-terms are used with a non-AFM based water model, only small changes in the ion properties are observed. The final combined models with TIP3P or TIP4P water reproduce the salt hydration free energies within 6% of experiments. The feasibility of combining AFM models with other non-AFM models is of significance since such combinations allow more complex systems to be studied without specific parameterization. In addition, the study suggests an interesting prospect of reusing the cross-terms when a part of a general force field is replaced with a different model. The prevailing practice, which is to re-derive all cross-terms with combining rules, may not have been optimal.

  13. A simplified GIS approach to modeling global leaf water isoscapes.

    Directory of Open Access Journals (Sweden)

    Jason B West

    Full Text Available The stable hydrogen (delta(2H and oxygen (delta(18O isotope ratios of organic and inorganic materials record biological and physical processes through the effects of substrate isotopic composition and fractionations that occur as reactions proceed. At large scales, these processes can exhibit spatial predictability because of the effects of coherent climatic patterns over the Earth's surface. Attempts to model spatial variation in the stable isotope ratios of water have been made for decades. Leaf water has a particular importance for some applications, including plant organic materials that record spatial and temporal climate variability and that may be a source of food for migrating animals. It is also an important source of the variability in the isotopic composition of atmospheric gases. Although efforts to model global-scale leaf water isotope ratio spatial variation have been made (especially of delta(18O, significant uncertainty remains in models and their execution across spatial domains. We introduce here a Geographic Information System (GIS approach to the generation of global, spatially-explicit isotope landscapes (= isoscapes of "climate normal" leaf water isotope ratios. We evaluate the approach and the resulting products by comparison with simulation model outputs and point measurements, where obtainable, over the Earth's surface. The isoscapes were generated using biophysical