WorldWideScience

Sample records for investigate water transport

  1. Cellular water distribution, transport, and its investigation methods for plant-based food material.

    Science.gov (United States)

    Khan, Md Imran H; Karim, M A

    2017-09-01

    Heterogeneous and hygroscopic characteristics of plant-based food material make it complex in structure, and therefore water distribution in its different cellular environments is very complex. There are three different cellular environments, namely the intercellular environment, the intracellular environment, and the cell wall environment inside the food structure. According to the bonding strength, intracellular water is defined as loosely bound water, cell wall water is categorized as strongly bound water, and intercellular water is known as free water (FW). During food drying, optimization of the heat and mass transfer process is crucial for the energy efficiency of the process and the quality of the product. For optimizing heat and mass transfer during food processing, understanding these three types of waters (strongly bound, loosely bound, and free water) in plant-based food material is essential. However, there are few studies that investigate cellular level water distribution and transport. As there is no direct method for determining the cellular level water distributions, various indirect methods have been applied to investigate the cellular level water distribution, and there is, as yet, no consensus on the appropriate method for measuring cellular level water in plant-based food material. Therefore, the main aim of this paper is to present a comprehensive review on the available methods to investigate the cellular level water, the characteristics of water at different cellular levels and its transport mechanism during drying. The effect of bound water transport on quality of food product is also discussed. This review article presents a comparative study of different methods that can be applied to investigate cellular water such as nuclear magnetic resonance (NMR), bioelectric impedance analysis (BIA), differential scanning calorimetry (DSC), and dilatometry. The article closes with a discussion of current challenges to investigating cellular water

  2. Numerical and experimental investigations for insulation particle transport phenomena in water flow

    Energy Technology Data Exchange (ETDEWEB)

    Krepper, Eckhard [Forschungszentrum Dresden Rossendorf e.V., (FZD), Institute of Safety Research, P.O. Box 510119, D-01314 Dresden (Germany)], E-mail: E.Krepper@fzd.de; Glover, Gregory Cartland; Grahn, Alexander; Weiss, Frank-Peter [Forschungszentrum Dresden Rossendorf e.V., (FZD), Institute of Safety Research, P.O. Box 510119, D-01314 Dresden (Germany); Alt, Soeren; Hampel, Rainer; Kaestner, Wolfgang; Kratzsch, Alexander; Seeliger, Andre [University of Applied Science Zittau/Goerlitz, Theodor Koerner Allee 16, D-02763 Zittau (Germany)

    2008-08-15

    The investigation of insulation debris generation, transport and sedimentation becomes more important with regard to reactor safety research for pressurized and boiling water reactors, when considering the long-term behaviour of emergency core coolant systems during all types of loss of coolant accidents (LOCA). The insulation debris released near the break during a LOCA incident consists of a mixture of a disparate particle population that varies with size, shape, consistency and other properties. Some fractions of the released insulation debris can be transported into the reactor sump, where it may perturb or impinge on the emergency core cooling systems. Open questions of generic interest are for example the particle load on strainers and corresponding pressure-drop, the sedimentation of the insulation debris in a water pool, its possible re-suspension and transport in the sump water flow. A joint research project on such questions is being performed in cooperation with the University of Applied Science Zittau/Goerlitz and the Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation and the development of computational fluid dynamic (CFD) models for the description of particle transport phenomena in coolant flow. While the experiments are performed at the University Zittau/Goerlitz, the theoretical work is concentrated at Forschungszentrum Dresden-Rossendorf. In the present paper, the basic concepts for computational fluid dynamic (CFD) modelling are described and experimental results are presented. Further experiments are designed and feasibility studies were performed.

  3. Investigation of tritium transport by the water courses from the territory of Krasnoyarsk MCC

    International Nuclear Information System (INIS)

    Nosov, A.V.; Martynova, A.M.; Shabanov, V.F.; Savitskij, Yu.V.; Shishlov, A.E.; Revenko, Yu.A.

    2001-01-01

    The problem of the Enisej river contamination as a result of tritium transport from the territory of the Krasnoyarsk Mining and Chemical Complex is discussed. The results of investigations realized for the Complex sewerage waters and streams running out from its territory and flowing into the Enisej river within the controlled area are analyzed. The investigations include hydrometric measurements of water flow rate, dosimetric measurements of of water stream profiles and sampling of water, bottom sediments, tidal soils, as well as hydrobionts for radioisotope and chemical analysis. Maximum tritium concentration revealed amounts to 125 Bq/l which is not dangerous from ecological viewpoint. The conclusion on necessity of the tritium monitoring in the zone affected by the Krasnoyarsk Mining and Chemical Complex is made [ru

  4. A Microfluidic Pore Network Approach to Investigate Water Transport in Fuel Cell Porous Transport Layers

    OpenAIRE

    Bazylak, A.; Berejnov, V.; Markicevic, B.; Sinton, D.; Djilali, N.

    2008-01-01

    Pore network modelling has traditionally been used to study displacement processes in idealized porous media related to geological flows, with applications ranging from groundwater hydrology to enhanced oil recovery. Very recently, pore network modelling has been applied to model the gas diffusion layer (GDL) of a polymer electrolyte membrane (PEM) fuel cell. Discrete pore network models have the potential to elucidate transport phenomena in the GDL with high computational efficiency, in cont...

  5. Geohydrology and possible transport routes of polychlorinated biphenyls in Haiku Valley, Oahu, Hawaii. Water resources investigation

    Energy Technology Data Exchange (ETDEWEB)

    Izuka, S.K.; Hill, B.R.; Shade, P.J.; Tribble, G.W.

    1991-01-01

    The report discusses geohydrologic evidence of ground-water and surface-water movement and sediment transport in an effort to identify routes by which water-borne contaminants may be transported within and beyond Haiku Valley. Specifically, the report describes the geologic framework of the valley and the bearing it has on the movement of ground water, and water budget of the Haiku Valley basin, the exchange between ground water and surface water, and the movement of sediment by surface water. The concentration of PCBs carried in suspended stream sediment is also described.

  6. Water transport in gas diffusion media for PEM fuel cells. Experimental and numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Joerg

    2010-08-20

    The water flux in partially saturated hydrophobic carbon fibre paper for polymer electrolyte membrane fuel cell applications is investigated and compared with the frequently used constitutive two-phase flow model based on Darcy's law. Further, the first steps towards a math-based material design for gas diffusion media are explored in this thesis. Two self-developed ex-situ experiments to investigate the liquid water transport are introduced. The first is a newly developed buoyancy-based measurement of the pressuresaturation relationship on thin porous material with an accuracy of 0.5 kPa for the pressure and {+-} 5% for the saturation. The second experiment measures the pressure drop in dependence of flow rates down to magnitudes of {mu}L/s across the partially saturated thin porous material. This flow rate is relevant for the fuel cell application. The liquid water transport through Toray 060 carbon fibre paper, impregnated with 7% and 10% PTFE is investigated at wet and dry boundary conditions. The experiments are also accompanied by analytical and numerical free surface modelling with the consideration of the material morphology and liquid-solid interaction. The imbibing and draining cases of an arrangement of six fibres at varying solid-liquid interaction and boundary conditions are studied with 'Surface Evolver'. In order to evaluate the findings of ex-situ and modelling work for applicability to water transport in fuel cell operation, the technique of nuclear magnetic resonance (NMR) imaging is assessed. The focus is on the visualisation of 2D and 3D water distribution in the operating fuel cell. The compatibility of the NMR experiment with fuel cell operation in relation to material selection, operating temperature, and current density is addressed. NMR imaging is employed for different current densities, stoichiometries, and fuel cell arrangements. The fuel cell arrangements differ by the cathode diffusion medium. Plain, hydrophobic, and

  7. Using molecular-scale tracers to investigate transport of agricultural pollutants in soil and water

    Science.gov (United States)

    Lloyd, C.; Michaelides, K.; Chadwick, D.; Dungait, J.; Evershed, R. P.

    2012-12-01

    We explore the use of molecular-scale tracers to investigate the transport of potential pollutants due to the application of slurry to soil. The molecular-scale approach allows us to separate the pollutants which are moved to water bodies through sediment-bound and dissolved transport pathways. Slurry is applied to agricultural land to as a soil-improver across a wide-range of topographic and climatic regimes, hence a set of experiments were designed to assess the effect of changing slope gradient and rainfall intensity on the transport of pollutants. The experiments were carried out using University of Bristol's TRACE (Test Rig for Advancing Connectivity Experiments) facility. The facility includes a dual axis soil slope (6 x 2.5 x 0.3 m3) and 6-nozzle rainfall simulator, which enables the manipulation of the slope to simulate different slope gradient and rainfall scenarios. Cattle slurry was applied to the top 1 metre strip of the experimental soil slope followed by four rainfall simulations, where the gradient (5° & 10°) and the rainfall intensity (60 & 120 mm hr-1) were co-varied. Leachate was sampled from different flow pathways (surface, subsurface and percolated) via multiple outlets on the slope throughout the experiments and soil cores were taken from the slope after each experiment. Novel tracers were used to trace the pollutants in both dissolved and sediment-bound forms. Fluorescence spectroscopy was used to trace dissolved slurry-derived material via water flow pathways, as the slurry was found to have a distinct signature compared with the soil. The fluorescence signatures of the leachates were compared with those of many organic compounds in order to characterise the origin of the signal. This allowed the assessment of the longevity of the signal in the environment to establish if it could be used as a robust long-term tracer of slurry material in water or if would be subject to transform processes through time. 5-βstanols, organic compounds

  8. Experimental investigation of gas hydrate formation, plugging and transportability in partially dispersed and water continuous systems

    Science.gov (United States)

    Vijayamohan, Prithvi

    in water. These experiments indicate that the partially dispersed systems tend to be problematic and are more severe cases with respect to flow assurance when compared to systems where the water is completely dispersed in oil. We have found that the partially dispersed systems are distinct, and are not an intermediate case between water dominated, and water-in-oil emulsified systems. Instead the experiments indicate that the hydrate formation and plugging mechanism for these systems are very complex. Hydrate growth is very rapid for such systems when compared to 100% water cut systems. The plugging mechanism for these systems is a combination of various phenomena (wall growth, agglomeration, bedding/settling, etc). Three different oils with different viscosities have been used to investigate the transportability of hydrates with respect to oil properties. The experiments indicate that the transportability of hydrates increases with increase in oil viscosity. The data from the tests performed provide the basis for a mechanistic model for hydrate formation and plugging in partially dispersed systems. It is found that in systems that were in stratified flow regime before hydrate onset, the hydrates eventually settled on the pipe walls thereby decreasing the flow area for the flow of fluids. In systems that were in the slug flow regime before hydrate formation, moving beds of hydrates were the main cause for plugging. In both the flow regimes, the systems studied entered a plugging regime beyond a certain hydrate concentration. This is termed as φplugging onset and can be used as an indicator to calculate the amount of hydrates that can be transported safely without requiring any additional treatment for a given set of flow characteristics. A correlation to calculate this hydrate concentration based on easily accessible parameters is developed in terms of flow characteristics and oil properties. The work performed in this thesis has enhanced the understanding of the

  9. Water-transporting proteins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas

    2010-01-01

    . In the K(+)/Cl(-) and the Na(+)/K(+)/2Cl(-) cotransporters, water is entirely cotransported, while water transport in glucose uniporters and Na(+)-coupled transporters of nutrients and neurotransmitters takes place by both osmosis and cotransport. The molecular mechanism behind cotransport of water...... transport. Epithelial water transport is energized by the movements of ions, but how the coupling takes place is uncertain. All epithelia can transport water uphill against an osmotic gradient, which is hard to explain by simple osmosis. Furthermore, genetic removal of aquaporins has not given support...... to osmosis as the exclusive mode of transport. Water cotransport can explain the coupling between ion and water transport, a major fraction of transepithelial water transport and uphill water transport. Aquaporins enhance water transport by utilizing osmotic gradients and cause the osmolarity...

  10. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Science.gov (United States)

    Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; Lee, Xuhui; Xiao, Ke; Chen, Zichong; Welp, Lisa R.; Schultz, Natalie M.; Gorski, Galen; Chen, Ming; Nieber, John

    2016-04-01

    Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle - an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from -40.2 to -15.9 ‰ and δ2Hv ranged from -278.7 to -113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol-1) indicate that regional evaporation can account

  11. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

    Directory of Open Access Journals (Sweden)

    T. J. Griffis

    2016-04-01

    Full Text Available Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle – an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL over a 3-year period (2010 to 2012. These measurements represent the first set of annual water vapor isotope observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from −40.2 to −15.9 ‰ and δ2Hv ranged from −278.7 to −113.0 ‰ and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( >  25 mmol mol−1

  12. A deuterium-based labeling technique for the investigation of rooting depths, water uptake dynamics and unsaturated zone water transport in semiarid environments

    Science.gov (United States)

    Beyer, M.; Koeniger, P.; Gaj, M.; Hamutoko, J. T.; Wanke, H.; Himmelsbach, T.

    2016-02-01

    Non- or minimum-invasive methods for the quantification of rooting depths of plants are rare, in particular in (semi-)arid regions; yet, this information is crucial for the parameterization of SVAT (Soil-Vegetation-Atmosphere Transfer) models and understanding of processes within the hydrological cycle. We present a technique utilizing the stable isotope deuterium (2H) applied as artificial tracer to investigate the vertical extent of the root zone, characterize water uptake dynamics of trees and shrubs at different depths and monitor transport of water through the unsaturated zone of dry environments. One liter of 35% deuterated water (2H2O) was punctually applied at several depths (0.5 m, 1 m, 2 m, 2.5 m and 4 m) at six different plots at a natural forested site in the Cuvelai-Etosha Basin (CEB), Namibia/Angola. Subsequently, uptake of the tracer was monitored by collecting plant samples (xylem and transpired water) up to seven days after tracer injection. Soil profiles at the plots were taken after the campaign and again after six months in order to evaluate the transport and distribution of 2H within the unsaturated zone. Of 162 plant samples taken, 31 samples showed clear signals of artificially introduced 2H, of which all originate from the plots labeled up to 2 m depth. No artificially injected 2H was found in plants when tracer application occurred deeper than 2 m. Results further indicate a sharing of water resources between the investigated shrubs and trees in the upper 1 m whilst tree roots seem to have better access to deeper layers of the unsaturated zone. The soil profiles taken after six months reveal elevated 2H-concentrations from depths as great as 4 m up to 1 m below surface indicating upward transport of water vapor. Purely diffuse transport towards the soil surface yielded an estimated 0.4 mm over the dry season. Results are of particular significance for a more precise parameterization of SVAT models and the formulation of water balances in

  13. The Mars Dust and Water Cycles: Investigating the Influence of Clouds on the Vertical Distribution and Meridional Transport of Dust and Water.

    Science.gov (United States)

    Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Brecht, A. S.; Urata, R.

    2015-01-01

    The dust and water cycles are critical to the current Martian climate, and they interact with each other through cloud formation. Dust modulates the thermal structure of the atmosphere and thus greatly influences atmospheric circulation. Clouds provide radiative forcing and control the net hemispheric transport of water through the alteration of the vertical distributions of water and dust. Recent advancements in the quality and sophistication of both climate models and observations enable an increased understanding of how the coupling between the dust and water cycles (through cloud formation) impacts the dust and water cycles. We focus here on the effects of clouds on the vertical distributions of dust and water and how those vertical distributions control the net meridional transport of water. We utilize observations of temperature, dust and water ice from the Mars Climate Sounder (MCS) on the Mars Reconnaissance Orbiter (MRO) and the NASA ARC Mars Global Climate Model (MGCM) to show that the magnitude and nature of the hemispheric exchange of water during NH summer is sensitive to the vertical structure of the simulated aphelion cloud belt. Further, we investigate how clouds influence atmospheric temperatures and thus the vertical structure of the cloud belt. Our goal is to isolate and understand the importance of radiative/dynamic feedbacks due to the physical processes involved with cloud formation and evolution on the current climate of Mars.

  14. Water transport in brain:

    DEFF Research Database (Denmark)

    MacAulay, Nanna; Hamann, Steffan; Zeuthen, Thomas

    2004-01-01

    It is generally accepted that cotransporters transport water in addition to their normal substrates, although the precise mechanism is debated; both active and passive modes of transport have been suggested. The magnitude of the water flux mediated by cotransporters may well be significant: both...... the number of cotransporters per cell and the unit water permeability are high. For example, the Na(+)-glutamate cotransporter (EAAT1) has a unit water permeability one tenth of that of aquaporin (AQP) 1. Cotransporters are widely distributed in the brain and participate in several vital functions: inorganic......(+)-lactate cotransporters. We have previously determined water transport capacities for these cotransporters in model systems (Xenopus oocytes, cell cultures, and in vitro preparations), and will discuss their role in water homeostasis of the astroglial cell under both normo- and pathophysiologal situations. Astroglia...

  15. Heat Transport upon River-Water Infiltration investigated by Fiber-Optic High-Resolution Temperature Profiling

    Science.gov (United States)

    Vogt, T.; Schirmer, M.; Cirpka, O. A.

    2010-12-01

    Infiltrating river water is of high relevance for drinking water supply by river bank filtration as well as for riparian groundwater ecology. Quantifying flow patterns and velocities, however, is hampered by temporal and spatial variations of exchange fluxes. In recent years, heat has become a popular natural tracer to estimate exchange rates between rivers and groundwater. Nevertheless, field investigations are often limited by insufficient sensors spacing or simplifying assumptions such as one-dimensional flow. Our interest lies in a detailed local survey of river water infiltration at a restored river section at the losing river Thur in northeast Switzerland. Here, we measured three high-resolution temperature profiles along an assumed flow path by means of distributed temperature sensing (DTS) using fiber optic cables wrapped around poles. Moreover, piezometers were equipped with standard temperature sensors for a comparison to the DTS data. Diurnal temperature oscillations were tracked in the river bed and the riparian groundwater and analyzed by means of dynamic harmonic regression and subsequent modeling of heat transport with sinusoidal boundary conditions to quantify seepage velocities and thermal diffusivities. Compared to the standard temperature sensors, the DTS data give a higher vertical resolution, facilitating the detection of process- and structure-dependent patterns of the spatiotemporal temperature field. This advantage overcompensates the scatter in the data due to instrument noise. In particular, we could demonstrate the impact of heat conduction through the unsaturated zone on the riparian groundwater by the high resolution temperature profiles.

  16. Water transport and energy.

    Science.gov (United States)

    Fricke, Wieland

    2017-06-01

    Water transport in plants occurs along various paths and is driven by gradients in its free energy. It is generally considered that the mode of transport, being either diffusion or bulk flow, is a passive process, although energy may be required to sustain the forces driving water flow. This review aims at putting water flow at the various organisational levels (cell, organ, plant) in the context of the energy that is required to maintain these flows. In addition, the question is addressed (1) whether water can be transported against a difference in its chemical free energy, 'water potential' (Ψ), through, directly or indirectly, active processes; and (2) whether the energy released when water is flowing down a gradient in its energy, for example during day-time transpiration and cell expansive growth, is significant compared to the energy budget of plant and cell. The overall aim of review is not so much to provide a definite 'Yes' and 'No' to these questions, but rather to stimulate discussion and raise awareness that water transport in plants has its real, associated, energy costs and potential energy gains. © 2016 John Wiley & Sons Ltd.

  17. Investigation of interactive effects on water flow and solute transport in sandy loam soil using time domain reflectometry.

    Science.gov (United States)

    Merdun, Hasan

    2012-01-01

    Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors like soil structure, initial soil water content (SWC), and application rate on preferential flow and transport were studied in a sandy loam field soil using measurement (by time domain reflectometry (TDR)) and modeling (by MACRO and VS2DTI) techniques. In addition, statistical analyses were performed to compare the means of the measured and modeled SWC and EC, and solute transport parameters (pore water velocity and dispersion coefficient) in 12 treatments. Research results showed that even though the effects of soil structural conditions on water and solute transport were not so clear, the applied solution moved lower depths in the profiles of wet versus dry initial SWC and high application rate versus low application rates. The effects of soil structure and initial SWC on water and solute movement could be differentiated under the interactive conditions, but the effects of the application rates were difficult to differentiate under different soil structural and initial SWC conditions. Modeling results showed that MACRO had somewhat better performance than VS2DTI in the estimation of SWC and EC with space and time, but overall both models had relatively low performances. The means of SWC, EC, and solute transport parameters of the 12 treatments were divided into some groups based on the statistical analyses, indicating different flow and transport characteristics or a certain degree nonuniform or preferential flow and transport in the soil. Conducting field experiments with more interactive factors and applying the models with different approaches may allow better understanding

  18. Osmotic water transport in aquaporins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Alsterfjord, Magnus; Beitz, Eric

    2013-01-01

    Abstract  We test a novel, stochastic model of osmotic water transport in aquaporins. A solute molecule present at the pore mouth can either be reflected or permeate the pore. We assume that only reflected solute molecules induce osmotic transport of water through the pore, while permeating solute...... molecules give rise to no water transport. Accordingly, the rate of water transport is proportional to the reflection coefficient σ, while the solute permeability, P(S), is proportional to 1 - σ. The model was tested in aquaporins heterologously expressed in Xenopus oocytes. A variety of aquaporin channel...... sizes and geometries were obtained with the two aquaporins AQP1 and AQP9 and mutant versions of these. Osmotic water transport was generated by adding 20 mM of a range of different-sized osmolytes to the outer solution. The osmotic water permeability and the reflection coefficient were measured...

  19. NMR and Electrochemical Investigation of the Transport Properties of Methanol and Water in Nafion and Clay-Nanocomposites Membranes for DMFCs

    Directory of Open Access Journals (Sweden)

    Vincenzo Baglio

    2012-06-01

    Full Text Available Water and methanol transport behavior, solvents adsorption and electrochemical properties of filler-free Nafion and nanocomposites based on two smectite clays, were investigated using impedance spectroscopy, DMFC tests and NMR methods, including spin-lattice relaxation and pulsed-gradient spin-echo (PGSE diffusion under variable temperature conditions. Synthetic (Laponite and natural (Swy-2 smectite clays, with different structural and physical parameters, were incorporated into the Nafion for the creation of exfoliated nanocomposites. Transport mechanism of water and methanol appears to be influenced from the dimensions of the dispersed platelike silicate layers as well as from their cation exchange capacity (CEC. The details of the NMR results and the effect of the methanol solution concentration are discussed. Clays particles, and in particular Swy-2, demonstrate to be a potential physical barrier for methanol cross-over, reducing the methanol diffusion with an evident blocking effect yet nevertheless ensuring a high water mobility up to 130 °C and for several hours, proving the exceptional water retention property of these materials and their possible use in the DMFCs applications. Electrochemical behavior is investigated by cell resistance and polarization measurements. From these analyses it is derived that the addition of clay materials to recast Nafion decreases the ohmic losses at high temperatures extending in this way the operating range of a direct methanol fuel cell.

  20. Using "CONNected objECT (CONNECT)" Algorithm to Explore Intense Global Water Vapor Transport to Investigate Impacts of Climate Variability and Change

    Science.gov (United States)

    Kawzenuk, B.; Sellars, S. L.; Nguyen, P.; Ralph, F. M.; Sorooshian, S.

    2017-12-01

    The CONNected objECT (CONNECT) algorithm is applied to Integrated Water Vapor Transport (IVT) data from the NASA's Modern-Era Retrospective Analysis for Research and Applications - Version 2 reanalysis product for the period 1980 to 2016 to study water vapor transport globally. The algorithm generates life-cycle records as statistical objects for the time and space location of the evolving strong vapor transport events. Global statistics are presented and used to investigate how climate variability impacts the events' location and frequency. Results show distinct water vapor object frequency and seasonal peaks during NH and SH Winter. Moreover, a positive linear trend in the annual number of objects is reported, increasing by 3.58 objects year-over-year (with 95% confidence, +/- 1.39). In addition, we show five distinct regions where these events typically exist (southeastern United States, eastern China, South Pacific south of 25°S, eastern South America and off the southern tip of South Africa), and where they rarely exist (eastern South Pacific Ocean and central southern Atlantic Ocean between 5°N-25°S). In addition, the event frequency and geographical location are also shown to be related to the Arctic Oscillation, Pacific North American Pattern, and the Quasi-Biennial Oscillation.

  1. Heavy metal transport by humic acid in underground water - investigations on europium; Untersuchungen zum huminstoffgetragenen Schwermetall-Transport im unterirdischen Wasser - durchgefuehrt am Beispiel des Europiums

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, D. (ed.)

    2001-12-01

    Colloids, i.e. particulates of 1 nm to 1 {mu}m suspended in water, are found in all types of groundwater, either as organic colloids, inorganic colloids, or mixtures of both. Their concentration, chemical composition, structure and particle size varies with the geochemistry of the sediment-water system. Inorganic colloids are Al-Fe-Mn mixed oxides, clays and other complex minerals. Organic colloids consist of humic and fulvic acids which are the main constituent of the dissolved organic carbon. Humic acids are capable of forming metal humate complexes with metal ions via proton-exchanging groups. Radionuclides, too, are transported with humic acid, especially trivalent and multivalent metal ions of the lanthanides and actinides as well as radio-iodine. [German] In allen Grundwaessern werden Kolloide, d.h. im Wasser suspendierte Teilchen mit Durchmessern im Bereich 1 nm bis 1 {mu}m gefunden. Die Zusammensetzung der Kolloide kann sowohl organischer als auch anorganischer Natur sein, wobei in vielen Grundwaessern eine Mischung beider Kolloidarten auftritt. Die Konzentration, die chemische Zusammensetzung, die Struktur und die Teilchengroesse natuerlicher Kolloide variieren stark, sie sind abhaengig von der Geochemie des Sediment-Wasser-Systems. Anorganische Kolloide sind Al-Fe-Mn-Mischoxide, Tone and andere komplexe Mineralien. Organische Kolloide bestehen aus Humin- und Fulvinsaeuren; diese Huminstoffe bilden den Hauptbestandteil des geloesten organischen Kohlenstoffs. Eine wichtige Eigenschaft der Huminstoffe ist ihre Faehigkeit, mit Metallionen ueber protonenaustauschende Gruppen Komplexe - sog. Metall-Humate - zu bilden. Auch Radionuklide, insbesondere drei- und mehrwertige Metallionen der Lanthaniden und Actiniden sowie Radio-Iod werden an Huminstoffe gebunden. Damit koennen Radionuklide nicht nur in Form einfacher Spezies, sondern auch huminstoffgebunden transportiert werden. (orig.)

  2. Students' Conceptions of Water Transport

    Science.gov (United States)

    Rundgren, Carl-Johan; Rundgren, Shu-Nu Chang; Schonborn, Konrad J.

    2010-01-01

    Understanding diffusion of water into and out of the cell through osmosis is fundamental to the learning and teaching of biology. Although this process is thought of as occurring directly across the lipid bilayer, the majority of water transport is actually mediated by specialised transmembrane water-channels called aquaporins. This study…

  3. Modelling Ballast Water Transport

    Digital Repository Service at National Institute of Oceanography (India)

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

    water in the marine environment. The bathymetry of the region has been taken from the CMAP data and augmented by data from hydrographic charts and bathymetry data available at NIO Data Center, Goa. Tides along the open boundary were generated...

  4. Investigating Water Problems. A Water Analysis Manual.

    Science.gov (United States)

    Renn, Charles E.

    This booklet has been prepared expressly for teachers and students who are interested in investigating the quality of water supplies. The intent is to provide technical support and background information concerning water quality factors and to give basic information on field and laboratory water testing techniques. It is assumed that the reader is…

  5. Water transport by the renal Na(+)-dicarboxylate cotransporter

    DEFF Research Database (Denmark)

    Meinild, A K; Loo, D D; Pajor, A M

    2000-01-01

    This study investigated the ability of the renal Na(+)-dicarboxylate cotransporter, NaDC-1, to transport water. Rabbit NaDC-1 was expressed in Xenopus laevis oocytes, cotransporter activity was measured as the inward current generated by substrate (citrate or succinate), and water transport...... was monitored by the changes in oocyte volume. In the absence of substrates, oocytes expressing NaDC-1 showed an increase in osmotic water permeability, which was directly correlated with the expression level of NaDC-1. When NaDC-1 was transporting substrates, there was a concomitant increase in oocyte volume....... This solute-coupled influx of water took place in the absence of, and even against, osmotic gradients. There was a strict stoichiometric relationship between Na(+), substrate, and water transport of 3 Na(+), 1 dicarboxylate, and 176 water molecules/transport cycle. These results indicate that the renal Na...

  6. Burning water: The water footprint of biofuel-based transport

    NARCIS (Netherlands)

    Gerbens-Leenes, Winnie; Hoekstra, Arjen Ysbert

    2010-01-01

    The trend towards substitution of conventional transport fuels by biofuels requires additional water. The EU aims to replace 10 percent of total transport fuels by biofuels by 2020. This study calculates the water footprint (WF) of different transport modes using bio-ethanol, biodiesel or

  7. Passive water and ion transport by cotransporters

    DEFF Research Database (Denmark)

    Loo, D D; Hirayama, B A; Meinild, A K

    1999-01-01

    the Lp of control oocytes. Passive Na+ transport (Na+ leak) was obtained from the blocker-sensitive Na+ currents in the absence of substrates (glucose and GABA). 2. Passive Na+ and water transport through SGLT1 were blocked by phlorizin with the same sensitivity (inhibitory constant (Ki), 3-5 micro......1. The rabbit Na+-glucose (SGLT1) and the human Na+-Cl--GABA (GAT1) cotransporters were expressed in Xenopus laevis oocytes, and passive Na+ and water transport were studied using electrical and optical techniques. Passive water permeabilities (Lp) of the cotransporters were determined from......M). When Na+ was replaced with Li+, phlorizin also inhibited Li+ and water transport, but with a lower affinity (Ki, 100 microM). When Na+ was replaced by choline, which is not transported, the SGLT1 Lp was indistinguishable from that in Na+ or Li+, but in this case water transport was less sensitive...

  8. Transport of Water in Semicrystalline Block Copolymer Membranes

    Science.gov (United States)

    Hallinan, Daniel; Oparaji, Onyekachi

    Poly(styrene)-block-poly(ethylene oxide) (PS- b-PEO) is a semicrystalline block copolymer (BCP) with interesting properties. It is mechanically tough, amphiphilic, and has a polar phase. The mechanical toughness is due to the crystallinity of PEO and the high glass transition temperature of PS, as well as the morphological structure of the BCP. The polymer has high CO2, water, and salt solubility that derive from the polar PEO component. Potential applications include CO2 separation, water purification, and lithium air batteries. In all of the aforementioned applications, water transport is an important parameter. The presence of water can also affect thermal and mechanical properties. Water transport and thermal and mechanical properties of a lamellar PS- b-PEO copolymer have been measured as a function of water activity. Water transport can be affected by the heterogeneous nature of a semicrystalline BCP. Therefore, Fourier transform infrared - attenuated total reflectance (FTIR-ATR) spectroscopy has been employed, because water transport and polymer swelling can be measured simultaneously. The effect of BCP structure on transport has been investigated by comparing water transport in PS- b-PEO to a PEO homopolymer. The crystalline content of the PEO and the presence of glassy PS lamellae will be used to explain the transport results.

  9. Radiological investigation of drinking water

    International Nuclear Information System (INIS)

    Kunz, E.

    1981-01-01

    An analysis is made of the report ''Radiological investigation of drinking water'' submitted by a working group of WHO to the Brussels meeting held between Nov 7 and 10, 1978. Annex II is emphasized of the WHO publication bearing the title ''The revision of WHO standards for drinking water''. It is shown that the draft of the revision does not basically differ from the revision introduced in Czechoslovakia and published in a revised standard CSN 83 0611 Drinking Water from 1978, including its harmonization with the Decree 59/72 Collect. of Laws on the protection of health from ionizing radiation, and from the standard CSN 83 0523 Radiometric analysis of drinking water. It is also shown that the text of the working group report contains some incorrect or unclear statements and views, which is explained by the misunderstanding of some ICRP recommendations. (H.S.)

  10. Transport Properties of Water and Sodium Dodecyl Sulfate (Postprint)

    Science.gov (United States)

    2013-08-01

    applicability and on the molecular system to be studied [34,46]. Bulk liquid properties using rigid water models are extensively studied and available...intended to be used to simulate bulk liquid water. In order to investigate the transport properties of the MP2f water model, we computed the diffusion... Monde , M., 2012, “Enhancement of Nucleate Pool Boiling Heat Transfer in Ammonia/Water Mixtures With a Surface-Active Agent,” Int. J. Heat Mass Transfer

  11. Leaf water stable isotopes and water transport outside the xylem.

    Science.gov (United States)

    Barbour, M M; Farquhar, G D; Buckley, T N

    2017-06-01

    How water moves through leaves, and where the phase change from liquid to vapour occurs within leaves, remain largely mysterious. Some time ago, we suggested that the stable isotope composition of leaf water may contain information on transport pathways beyond the xylem, through differences in the development of gradients in enrichment within the various pathways. Subsequent testing of this suggestion provided ambiguous results and even questioned the existence of gradients in enrichment within the mesophyll. In this review, we bring together recent theoretical developments in understanding leaf water transport pathways and stable isotope theory to map a path for future work into understanding pathways of water transport and leaf water stable isotope composition. We emphasize the need for a spatially, anatomically and isotopically explicit model of leaf water transport. © 2016 John Wiley & Sons Ltd.

  12. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products spanning the 1987/1988 El Nino Southern Oscillation (ENSO)...

  13. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products from the GOES-8 satellite spanning the 1987-1988 El Nino...

  14. 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

  15. Modelling anisotropic water transport in polymer composite

    Indian Academy of Sciences (India)

    This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation models were ...

  16. Modelling anisotropic water transport in polymer composite ...

    Indian Academy of Sciences (India)

    Abstract. This work reports anisotropic water transport in a polymer composite consisting of an epoxy matrix reinforced with aligned triangular bars made of vinyl ester. By gravimetric experiments, water diffusion in resin and polymer composites were characterized. Parameters for Fickian diffusion and polymer relaxation ...

  17. Fluid transport with time on peritoneal dialysis: the contribution of free water transport and solute coupled water transport

    NARCIS (Netherlands)

    Coester, Annemieke M.; Smit, Watske; Struijk, Dirk G.; Krediet, Raymond T.

    2009-01-01

    Ultrafiltration in peritoneal dialysis occurs through endothelial water channels (free water transport) and together with solutes across small pores: solute coupled water transport. A review is given of cross-sectional studies and on the results of longitudinal follow-up

  18. Investigation of RFID Based Sensors for Sustainable Transportation Applications

    Science.gov (United States)

    2011-01-21

    Through support of a University Transportation Research Center Faculty Development Minigrant an investigation was made into the use of RFID based sensing technologies for transportation purposes. Transportation applications would potentially include ...

  19. Heat Transfer in Directional Water Transport Fabrics

    Directory of Open Access Journals (Sweden)

    Chao Zeng

    2016-10-01

    Full Text Available Directional water transport fabrics can proactively transfer moisture from the body. They show great potential in making sportswear and summer clothing. While moisture transfer has been previously reported, heat transfer in directional water transport fabrics has been little reported in research literature. In this study, a directional water transport fabric was prepared using an electrospraying technique and its heat transfer properties under dry and wet states were evaluated, and compared with untreated control fabric and the one pre-treated with NaOH. All the fabric samples showed similar heat transfer features in the dry state, and the equilibrium temperature in the dry state was higher than for the wet state. Wetting considerably enhanced the thermal conductivity of the fabrics. Our studies indicate that directional water transport treatment assists in moving water toward one side of the fabric, but has little effect on thermal transfer performance. This study may be useful for development of “smart” textiles for various applications.

  20. Mechanisms and regulation of water transport across the peritoneal membrane

    OpenAIRE

    Morelle, Johann

    2016-01-01

    Peritoneal dialysis represents the major home-based dialysis modality for patients with end-stage renal disease. The capacity of the peritoneal membrane to transport water in response to an osmotic gradient contributes to the efficiency of the technique. Previous studies have demonstrated that aquaporin water channels are expressed in the endothelium lining peritoneal microvessels and mediate ultrafiltration during peritoneal dialysis. The investigations presented in this work provide novel i...

  1. Coupled water transport by rat proximal tubule.

    Science.gov (United States)

    Green, R; Giebisch, G; Unwin, R; Weinstein, A M

    1991-12-01

    Simultaneous microperfusion of proximal tubules and peritubular capillaries in kidneys of rats anesthetized with Inactin was used to examine water reabsorption by this epithelium. Osmolality of the luminal solution was varied with changes in NaCl concentration and by the addition of raffinose. Capillary perfusates contained either low (2 g/dl) or high (16 g/dl) concentrations of albumin. We used low-bicarbonate perfusates for both lumen and capillary so that we might apply the nonequilibrium thermodynamic model of transport for a single solute (NaCl) to interpret our observations. Linear regression with the volume flux equation Jv = -Lp delta II - Lp sigma delta C + Jav (where Jv is volume flux, Lp is hydraulic conductance, delta II is oncotic force, sigma is osmotic reflection coefficient, delta C is salt concentration difference, and Jav is the component of Jv not attributed to transepithelial hydrostatic or osmotic forces) revealed a tubule water permeability (Pf = 0.11 +/- 0.01 cm/s) and a sigma (0.74 +/- 0.08) in agreement with previous determinations. These transport parameters were unaffected by changes in peritubular protein. We also found that Jav was substantial, approximately three-fourths of the rate of isotonic transport under these perfusion conditions. Further, this component of water transport nearly doubled with the transition from low- to high-protein peritubular capillary perfusion. When expressed as a capacity for water reabsorption against an osmotic gradient, the salt concentration differences required to null volume flux were 13.2 +/- 2.4 and 29.4 +/- 4.0 mosmol/kgH2O under low and high peritubular protein. Our data suggest that this protein effect is, most likely, an increase in solute transport by the tubule epithelial cells.

  2. Mercury-cycling in surface waters and in the atmosphere - species analysis for the investigation of transformation and transport properties of mercury

    International Nuclear Information System (INIS)

    Ebinghaus, R.; Hintelmann, H.; Wilken, R.D.

    1994-01-01

    The river Elbe has been one of the most contaminated rivers with regard to mercury for many years. In 1991 a length-profile has been measured for mercury and methylmercury (CH 3 Hg + ) from Obristvi, Czech Republic, to the German bight. Total mercury has been measured by cold vapor atomic absorption spectrometry (CVAAS). The organo mercury compounds have been separated by high performance liquid chromatography (HPLC) connected on-line to an atomic fluorescence spectrometer (AFS) by a continuous flow-system. Total mercury up to 120 mg Hg + /kg and CH 3 Hg + concentrations up to 130 μg CH 3 Hg + /kg could be detected in special sites. The formation of CH 3 Hg + in sediments can be caused besides the methylation of mercury, by sulphate reducing or methanogenic bacteria and transmethylation reactions with organometals. Atmospheric mercury concentrations have been measured at three different European sites. Samples have been collected on gold-coated glass balls or on quartz wool, respectively. After thermal desorption mercury has been determined using the two step amalgamation technique with AFS detection. Compared to natural background concentrations of total gaseous mercury (TGM), slightly increased levels could be detected at a rural site in Germany. This increase can probably be explained by long-range transport processes. Within the vicinity of a inactivated mercury production plant high concentrations of up to 13.5 ng/m 3 particle associated mercury (Hg part ) have been detected. Consequently, dry deposition of mercury in the particulate form can intensify the total deposition flux close to Hg-emitting sources. (orig.)

  3. Impact of Interfacial Water Transport in PEMFCs on Cell Performance

    International Nuclear Information System (INIS)

    Kotaka, Toshikazu; Tabuchi, Yuichiro; Pasaogullari, Ugur; Wang, Chao-Yang

    2014-01-01

    Coupled cell performance evaluation, liquid water visualization by neutron radiography (NRG) and numerical modeling based on multiphase mixture (M2) model were performed with three types of GDMs: Micro Porous Layer (MPL) free; Carbon Paper (CP) with MPL; and CP free to investigate interfacial liquid water transport phenomena in PEMFCs and its effect on cell performance. The visualized results of MPL free GDM with different wettability of bi-polar plates (BPPs) showed hydrophilic BPP improved liquid water transport at the interface between CP and channel. Numerical modeling results indicated that this difference with BPP wettability was caused by the liquid water coverage difference on CP surface. Thus, controlling liquid water coverage is the one of the key strategies for improving cell performance. Additionally, liquid water distributions across the cell for three types of GDMs were compared and significant difference in liquid water content at the interface between Catalyst Layer (CL) and GDM was observed. Numerical modeling suggests this difference is influenced by the gap at the interface and that the MPL could minimize this effect. The CP free cell (i.e. only MPL) showed the best performance and the lowest liquid water content. There were multiple impacts of interfacial liquid water transport both at CL-GDM and GDM-channel interfaces. High hydrophobicity and fine structure of MPLs contributed to enhanced liquid water transport at GDM-channel interface and as a result reduced the liquid water coverage. At the same time, MPL improves contact at the CL-GDM interface in the same manner as seen in CP with MPL case. Thus, the CP free concept showed the best performance. It is suggested that the design of the interface between each component of the PEMFC has a great impact on cell performance and plays a significant role in achievement of high current density operation and cost reduction in FCEVs

  4. Electronic transport in partially ionized water plasmas

    Science.gov (United States)

    French, Martin; Redmer, Ronald

    2017-09-01

    We use ab initio simulations based on density functional theory to calculate the electrical and thermal conductivities of electrons in partially ionized water plasmas at densities above 0.1 g/cm3. The resulting conductivity data are then fitted to analytic expressions for convenient application. For low densities, we develop a simple and fully analytic model for electronic transport in low-density plasmas in the chemical picture using the relaxation-time approximation. In doing so, we derive a useful analytic expression for electronic transport cross sections with neutral particles, based on a model potential. In the regime of thermal ionization, electrical conductivities from the analytic model agree with the ab initio data within a factor of 2. Larger deviations are observed for the thermal conductivity, and their origin is discussed. Our results are relevant for modeling the interior and evolution of water-rich planets as well as for technical plasma applications.

  5. Investigation of the transportation requirements for fusion power plants

    International Nuclear Information System (INIS)

    Rhoads, R.E.; Davis, D.K.

    1976-09-01

    This report presents a general investigation of the transport requirements associated with the construction and operation of conceptual fusion reactors. Projections of amounts of construction and operating materials requiring transportation are presented for several proposed designs. The material to be shipped is described along with the shipping containers that might be used, the transport modes and the expected impact of transporting these materials. Transportation of both radioactive and nonradioactive materials will be required. Most of these materials are routinely shipped by the transportation industry. Transportation requirements of a representative fusion reactor are also compared with Liquid Metal Fast Breeder Reactor (LMFBR) requirements

  6. Free water transport, small pore transport and the osmotic pressure gradient

    NARCIS (Netherlands)

    Parikova, Alena; Smit, Watske; Zweers, Machteld M.; Struijk, Dirk G.; Krediet, Raymond T.

    2008-01-01

    BACKGROUND: Water transport in peritoneal dialysis (PD) patients occurs through the small pores and water channels, the latter allowing free water transport (FWT). The osmotic gradient is known to be one of the major determinants of water transport. The objective of the study was to analyse the

  7. Investigating transport pathways in the ocean

    Science.gov (United States)

    Griffa, Annalisa; Haza, Angelique; Özgökmen, Tamay M.; Molcard, Anne; Taillandier, Vincent; Schroeder, Katrin; Chang, Yeon; Poulain, P.-M.

    2013-01-01

    The ocean is a very complex medium with scales of motion that range from thousands of kilometers to the dissipation scales. Transport by ocean currents plays an important role in many practical applications ranging from climatic problems to coastal management and accident mitigation at sea. Understanding transport is challenging because of the chaotic nature of particle motion. In the last decade, new methods have been put forth to improve our understanding of transport. Powerful tools are provided by dynamical system theory, that allow the identification of the barriers to transport and their time variability for a given flow. A shortcoming of this approach, though, is that it is based on the assumption that the velocity field is known with good accuracy, which is not always the case in practical applications. Improving model performance in terms of transport can be addressed using another important methodology that has been recently developed, namely the assimilation of Lagrangian data provided by floating buoys. The two methodologies are technically different but in many ways complementary. In this paper, we review examples of applications of both methodologies performed by the authors in the last few years, considering flows at different scales and in various ocean basins. The results are among the very first examples of applications of the methodologies to the real ocean including testing with Lagrangian in-situ data. The results are discussed in the general framework of the extended fields related to these methodologies, pointing out to open questions and potential for improvements, with an outlook toward future strategies.

  8. Water transport in graphene nano-channels

    DEFF Research Database (Denmark)

    Wagemann, Enrique; Oyarzua, Elton; Walther, J. H.

    The transport of water in nanopores is of both fundamental and practical interest. Graphene Channels (GCs) are potential building blocks for nanofluidic devices dueto their molecularly smooth walls and exceptional mechanical properties. Numerous studies have found a significant flow rate enhancem......The transport of water in nanopores is of both fundamental and practical interest. Graphene Channels (GCs) are potential building blocks for nanofluidic devices dueto their molecularly smooth walls and exceptional mechanical properties. Numerous studies have found a significant flow rate...... between the chirality of the graphene walls and the slip length has not been established. In this study, we perform non-equilibrium molecular dynamics simulations of water flow in single- and multi-walled GCs. We examine the influence on the flow rates of dissipating the viscous heat produced...... by connecting the thermostat to the water molecules, the CNT wall atoms or both of them. From the atomic trajectories, we compute the fluid flow rates in GCs with zig-zag and armchair walls, heights from 1 to 4 nm and different number of graphene layers on the walls. A relation between the chirality, slip...

  9. Transport Models for Inland and Coastal Waters

    Science.gov (United States)

    Hamilton, Peter

    This proceedings volume originates from a symposium held at Berkeley, California, in August 1980. The purpose of the symposium was to assess the ability of models to predict surface water flow and the transport of dissolved substances in natural systems. The authors were invited, after an initial call for papers, by a Scientific Committee of the International Association for Hydraulic Research.In this context, predictive modeling is limited to hydrodynamic and transport models as applied to rivers, estuaries, shallow coastal waters, lakes, and reservoirs. This is a large subject, though evidently not the whole story on predictive techniques applied to natural water bodies, and many different models are described with applications to a wide variety of natural systems. There is relatively little overlap of material between chapters. It is noteworthy that 21 out of 24 authors of the chapters are affiliated with institutions outside the United States, and many of these are from large European hydraulic laboratories. A number of the chapters summarize numerical modeling studies undertaken by these institutions and so provide the U.S. reader with valuable references to the European open literature and laboratory technical reports. The latter are not usually readily available in the United States. This bias reflects a greater willingness of European engineers to employ sophisticated hydrodynamic numerical models as tools for the solution of engineering and environmental problems of natural water bodies.

  10. Transport properties of supercooled confined water

    International Nuclear Information System (INIS)

    Mallamace, F.; Baglioni, P.; Corsaro, C.; Spooren, J.; Stanley, H.E.; Chen, S.-H.

    2011-01-01

    We present an overview of recent experiments performed on water in the deeply supercooled region, a temperature region of fundamental importance in the science of water. We examine data generated by nuclear magnetic resonance, quasi-elastic neutron scattering, Fourier-transform infrared spectroscopy, and Raman spectroscopy, and study water confined in nanometer-scale environments. When contained within small pores, water does not crystallize and can be supercooled well below its homogeneous nucleation temperature T H. On this basis, it is possible to carry out a careful analysis of the well-known thermodynamic anomalies of water. Studying the temperature and pressure dependencies of water dynamics, we show that the liquid-liquid phase transition (LLPT) hypothesis represents a reliable model for describing liquid water. In this model, liquid water is a mixture of two different local structures: a low density liquid (LDL) and a high-density liquid (HDL). The LLPT line terminates at a low-T liquid-liquid critical point. We discuss the following experimental findings: 1.) the crossover from non-Arrhenius behavior at high T to Arrhenius behavior at low T in transport parameters; 2.) the breakdown of the Stokes-Einstein relation; 3.) the existence of a Widom line, which is the locus of points corresponding to a maximum correlation length in the P-T phase diagram and which ends in the liquid-liquid critical point; 4.) the direct observation of the LDL phase; and 5.) the minimum in the density at approximately 70 K below the temperature of the density maximum. In our opinion these results strongly support the LLPT hypothesis. All of the basic science and technology community should be impressed by the fact that, although the few ideas (apparently elementary) developed concerning water approximately 27 centuries ago have changed very little up to now, because of the current expansion in our knowledge in this area, they can begin to change in the near future.

  11. Fast water transport in graphene nanofluidic channels.

    Science.gov (United States)

    Xie, Quan; Alibakhshi, Mohammad Amin; Jiao, Shuping; Xu, Zhiping; Hempel, Marek; Kong, Jing; Park, Hyung Gyu; Duan, Chuanhua

    2018-03-01

    Superfast water transport discovered in graphitic nanoconduits, including carbon nanotubes and graphene nanochannels, implicates crucial applications in separation processes and energy conversion. Yet lack of complete understanding at the single-conduit level limits development of new carbon nanofluidic structures and devices with desired transport properties for practical applications. Here, we show that the hydraulic resistance and slippage of single graphene nanochannels can be accurately determined using capillary flow and a novel hybrid nanochannel design without estimating the capillary pressure. Our results reveal that the slip length of graphene in the graphene nanochannels is around 16 nm, albeit with a large variation from 0 to 200 nm regardless of the channel height. We corroborate this finding with molecular dynamics simulation results, which indicate that this wide distribution of the slip length is due to the surface charge of graphene as well as the interaction between graphene and its silica substrate.

  12. Investigation of two-phase transport phenomena in microchannels using a microfabricated experimental structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fumin [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States)]. E-mail: fuminmems@gmail.com; Steinbrenner, Julie E. [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Hidrovo, Carlos H. [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Kramer, Theresa A. [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Lee, Eon Soo [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Vigneron, Sebastien [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Cheng, Ching-Hsiang [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Eaton, John K. [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States); Goodson, Kenneth E. [Mechanical Engineering Department, Stanford University, Room 224, Building 530, Stanford, CA 94305-3030 (United States)

    2007-07-15

    Microchannels (0.05-1 mm) improve gas routing in proton exchange membrane fuel cells, but add to the complexities of water management. This work microfabricates experimental structures with distributed water injection as well as with heating and temperature sensing capabilities to study water formation and transport. The samples feature optical access to allow visualization and distributed thermometry for investigation of two-phase flow transport phenomena in the microchannels. The temperature evolution along the channel is observed that the temperature downstream of the distributed water injection decreases as the pressure drop increases. As the water injection rate is lower than 200 {mu}l/min, there exists a turning point where temperature increases as the pressure drop increases further. These micromachined structures with integrated temperature sensors and heaters are key to the experimental investigation as well as visualization of two-phase flow and water transport phenomena in microchannels for fuel cell applications.

  13. Hydrogeophysical investigations of unsaturated flow and transport

    DEFF Research Database (Denmark)

    Haarder, Eline Bojsen

    -dimensional cross-borehole electrical resistivity tomography (ERT). In another experiment GPR and microgravimetry measurements were used for monitoring the moisture content changes arising from a forced infiltration of water across a large area. Results from both of these experiments showed that small changes...

  14. experimental investigation of sand minimum transport velocity

    African Journals Online (AJOL)

    user

    The justification for experimental work was evident from the inconsistent and inaccurate results obtained using existing analytical models for MTV predictions. .... At the end of each experimental run, the sand particle was separated from mixture using a filter. The water is then re-circulated into the system continuously.

  15. Transport and transformation of surface water masses across the ...

    African Journals Online (AJOL)

    Transport and transformation of surface water masses across the Mascarene Plateau during the Northeast Monsoon season. ... Mixing occurs in the central gap between intermediate water masses (Red Sea Water [RSW] and Antarctic Intermediate Water [AAIW]) as well as in the upper waters (Subtropical Surface Water ...

  16. Hydrogeophysical investigations of unsaturated flow and transport

    DEFF Research Database (Denmark)

    Haarder, Eline Bojsen

    -dimensional cross-borehole electrical resistivity tomography (ERT). In another experiment GPR and microgravimetry measurements were used for monitoring the moisture content changes arising from a forced infiltration of water across a large area. Results from both of these experiments showed that small changes...... in grain size and sorting degree of the sand were responsible for initiating heterogeneous development of the injected tracer plume as well as the irregular moisture content development caused by the forced infiltration. In the final experiment, cross-borehole ERT data were used for estimation of natural...

  17. Procedures for ground-water investigations

    International Nuclear Information System (INIS)

    1992-12-01

    This manual was developed by the Pacific Northwest Laboratory (PNL) to document the procedures used to carry out and control the technical aspects of ground-water investigations at the PNL. Ground-water monitoring procedures are developed and used in accordance with the PNL Quality Assurance Program

  18. Ecological aspects of water coal fuel transportation and application

    Directory of Open Access Journals (Sweden)

    Anna SHVORNIKOVA

    2010-01-01

    Full Text Available This paper deals with the aspects of influence of transportation process and burning of water coal fuel on an ecological condition of environment. Also mathematical dependences between coal ash level and power consumption for transportation are presented.

  19. 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.

  20. Investigation on aerosol transport in containment cracks

    International Nuclear Information System (INIS)

    Parozzi, F.; Chatzidakis, S.; Housiadas, C.; Gelain, T.; Nahas, G.; Plumecocq, W.; Vendel, J.; Herranz, L.E.; Hinis, E.; Journeau, C.; Piluso, P.; Malgarida, E.

    2005-01-01

    Under severe accident conditions, the containment leak-tightness could be threatened by energetic phenomena that could yield a release to the environment of nuclear aerosols through penetrating concrete cracks. As few data are presently available to quantify this aerosol leakage, a specific action was launched in the framework of the Santar Project of the European 6 th Framework Programme. In this context, both theoretical and experimental investigations have been managed to develop a model that can readily be applied within a code like Aster (Accident Source Term Evaluation Code). Particle diffusion, settling, turbulent deposition, diffusiophoresis and thermophoresis have been considered as deposition mechanisms inside the crack path. They have been encapsulated in numerical models set up to reproduce experiments with small tubes and capillaries and simulate the plug formation. Then, an original lagrangian approach has been used to evaluate the crack retention under typical PWR accident conditions, comparing its predictions with those given by the eulerian approach implemented in the ECART code. On the experimental side, the paper illustrates an aerosol production and measurement system developed to validate aerosol deposition models into cracks and the results that can be obtained: a series of tests were performed with monodispersed fluorescein aerosols injected into a cracked concrete sample. A key result that should be further explored refers to the high enhancement of aerosol retention that could be due to steam condensation. Recommendations concerning future experimentation are also given in the paper. (author)

  1. Investigating hydraulic transport and disposal of coal ash at the Gacko thermal power plant

    Energy Technology Data Exchange (ETDEWEB)

    Knezevic, D.; Grbovic, M.; Petrovic, M.

    1986-01-01

    This paper discusses ash transport difficulties at the Gacko thermal power station. Designed dumper transport failed due to violent thermal reactions in water-sprayed ash during transport. An system was designed by the Institute for Ore Processing of Belgrade. Large-scale investigation of ash properties and slurry consolidation were conducted prior to hydraulic transport testing. A semi-industrial hydraulic transport was built and tested for ash disposal. It was found that Gacko power station ash may be safely transported by pipeline and disposed in layers 10 cm thick without danger of operation breaks due to ash caking within the pipeline. A sketch of the hydraulic transport system is presented. 4 refs.

  2. Water transport between CNS compartments: contributions of aquaporins and cotransporters

    DEFF Research Database (Denmark)

    MacAulay, N; Zeuthen, T

    2010-01-01

    or hydrocephalus. The molecular pathways by which water molecules cross the cell membranes of the brain are not well-understood, although the discovery of aquaporin 4 (AQP4) in the brain improved our understanding of some of these transport processes, particularly under pathological conditions. In the present...... review we introduce another family of transport proteins as water transporters, namely the cotransporters and the glucose uniport GLUT1. In direct contrast to the aquaporins, these proteins have an inherent ability to transport water against an osmotic gradient. Some of them may also function as water...

  3. Investigation of drinking water quality in Kosovo.

    Science.gov (United States)

    Berisha, Fatlume; Goessler, Walter

    2013-01-01

    In the recent years, not much environmental monitoring has been conducted in the territory of Kosovo. This study represents the first comprehensive monitoring of the drinking water situation throughout most of the territory of Kosovo. We present the distribution of major and minor trace elements in drinking water samples from Kosovo. During our study we collected 951 samples from four different sources: private-bored wells; naturally flowing artesian water; pumped-drilled wells; and public water sources (tap water). The randomly selected drinking water samples were investigated by routine water analyses using inductively coupled plasma mass spectrometry (ICPMS) for 32 elements (Li, Be, B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Te, Ba, Tl, Pb, Bi, Th, U). Even though there are set guidelines for elemental exposure in drinking water worldwide, in developing countries, such as Kosovo, the lack of monitoring drinking water continues to be an important health concern. This study reports the concentrations of major and minor elements in the drinking water in Kosovo. Additionally, we show the variation of the metal concentration within different sources. Of the 15 regulated elements, the following five elements: Mn, Fe, Al, Ni, As, and U were the elements which most often exceeded the guidelines set by the EU and/or WHO.

  4. Investigation of anisotropic thermal transport in cross-linked polymers

    Science.gov (United States)

    Simavilla, David Nieto

    Thermal transport in lightly cross-linked polyisoprene and polybutadine subjected to uniaxial elongation is investigated experimentally. We employ two experimental techniques to assess the effect that deformation has on this class of materials. The first technique, which is based on Forced Rayleigh Scattering (FRS), allows us to measure the two independent components of the thermal diffusivity tensor as a function of deformation. These measurements along with independent measurements of the tensile stress and birefringence are used to evaluate the stress-thermal and stress-optic rules. The stress-thermal rule is found to be valid for the entire range of elongations applied. In contrast, the stress-optic rule fails for moderate to large stretch ratios. This suggests that the degree of anisotropy in thermal conductivity depends on both orientation and tension in polymer chain segments. The second technique, which is based on infrared thermography (IRT), allows us to measure anisotropy in thermal conductivity and strain induced changes in heat capacity. We validate this method measurements of anisotropic thermal conductivity by comparing them with those obtained using FRS. We find excellent agreement between the two techniques. Uncertainty in the infrared thermography method measurements is estimated to be about 2-5 %. The accuracy of the method and its potential application to non-transparent materials makes it a good alternative to extend current research on anisotropic thermal transport in polymeric materials. A second IRT application allows us to investigate the dependence of heat capacity on deformation. We find that heat capacity increases with stretch ratio in polyisoprene specimens under uniaxial extension. The deviation from the equilibrium value of heat capacity is consistent with an independent set of experiments comparing anisotropy in thermal diffusivity and conductivity employing FRS and IRT techniques. We identify finite extensibility and strain

  5. Investigation on bulk water: Integral equation approach

    International Nuclear Information System (INIS)

    Adebayo, G.A.; Akinlade, O.; Hussain, L. A.; Forstmann, F.

    2001-08-01

    The static structure factor of water has been investigated using the central force model (CFM). Due to inadequacy of the HNC closure in describing the complex hydrogen bond interactions, we have used a bridge function obtained by adjusting the HH bond lengths. The modification results in an improvement in the theoretical structure factors. In addition to this, we examine other water models and provide a compilation of structural and thermodynamic results obtained from them. (author)

  6. Speciation and transport of radionuclides in ground water

    International Nuclear Information System (INIS)

    Robertson, D.E.; Toste, A.P.; Abel, K.H.; Cowan, C.E.; Jenne, E.A.; Thomas, C.W.

    1984-01-01

    Studies of the chemical speciation of a number of radionuclides migrating in a slightly contaminated ground water plume are identifying the most mobile species and providing an opportunity to test and/or validate geochemical models of radionuclide transport in ground waters. Results to date have shown that most of the migrating radionuclides are present in anionic or nonionic forms. These include anionic forms of 55 Fe, 60 Co, /sup 99m/Tc, 106 Ru, 131 I, and nonionic forms of 63 Ni and 125 Sb. Strontium-70 and a small fraction of the mobile 60 Co are the only cationic radionuclides which have been detected moving in the ground water plume beyond 30 meters from the source. A comparison of the observed chemical forms with the predicted species calculated from modeling thermodynamic data and ground water chemical parameters has indicated a good agreement for most of the radioelements in the system, including Tc, Np, Cs, Sr, Ce, Ru, Sb, Zn, and Mn. The discrepancies between observed and calculated solutions species were noted for Fe, Co, Ni and I. Traces of Fe, Co, and Ni were observed to migrate in anionic or nonionic forms which the calculations failed to predict. These anionic/nonionic species may be organic complexes having enhanced mobility in ground waters. The radioiodine, for example, was shown to behave totally as an anion but further investigation revealed that 49-57% of this anionic iodine was organically bound. The ground water and aqueous extracts of trench sediments contain a wide variety of organic compounds, some of which could serve as complexing agents for the radionuclides. These results indicate the need for further research at a variety of field sites in defining precisely the chemical forms of the mobile radionuclide species, and in better understanding the role of dissolved organic materials in ground water transport of radionuclides

  7. K9 water searches: scent and scent transport considerations.

    Science.gov (United States)

    Osterkamp, Tom

    2011-07-01

    Increased use of water search dogs for detecting submerged bodies has created the need for a better understanding of scent emanating from the bodies and how it transits the water to the dog's nose. A review of recent literature identifies likely scent sources, potential scent transport processes, and research needs. Scent sources include gases in bubbles or dissolved in the water, liquids as buoyant plumes and droplets or dissolved in the water, and solids consisting of buoyant particulates with secretions, bacteria, and body fluids. Potential transport processes through the water include buoyancy, entrainment, and turbulence. Transport processes from the water surface into the air include volatilization and evaporation enhanced by bubble bursting, breaking waves, splashing, and wind spray. Implications for the use of water search dogs are examined. Observations of submerged, decomposing bodies are needed to quantify the physical and chemical characteristics of the scent and scent transport processes. © 2011 American Academy of Forensic Sciences.

  8. Molecular mechanisms of water transport in the eye

    DEFF Research Database (Denmark)

    Hamann, Steffen

    2002-01-01

    in a general model for water transport in ocular epithelia. Some water-transporting membranes contain aquaporins, others do not. The ultrastructure is also variable among the cell layers and cannot be fitted into a general model. On the other hand, the direction of cotransport in symporters complies...

  9. Simultaneous transport of water and solutes under transient ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 117; Issue 4. Simultaneous transport of water and solutes under transient unsaturated flow conditions – A case study ... Keywords. Hydraulic conductivity; infiltration; leaching; Malaprabha; modeling; permeability; salinity; solute transport; SWIM model; water flow.

  10. The Economics of Bulk Water Transport in Southern California

    Directory of Open Access Journals (Sweden)

    Andrew Hodges

    2014-12-01

    Full Text Available Municipalities often face increasing demand for limited water supplies with few available alternative sources. Under some circumstances, bulk water transport may offer a viable alternative. This case study documents a hypothetical transfer between a water utility district in northern California and urban communities located on the coast of central and southern California. We compare bulk water transport costs to those of constructing a new desalination facility, which is the current plan of many communities for increasing supplies. We find that using water bags to transport fresh water between northern and southern California is in some instances a low-cost alternative to desalination. The choice is constrained, however, by concerns about reliability and, thus, risk. Case-study results demonstrate the challenges of water supply augmentation in water-constrained regions.

  11. Procedures for ground-water investigations

    International Nuclear Information System (INIS)

    1989-09-01

    This manual was developed by the Pacific Northwest Laboratory (PNL) to document the procedures used to carry out and control the technical aspects of ground-water investigations at the PNL. Ground-water investigations are carried out to fulfill the requirements for the US Department of Energy (DOE) to meet the requirements of DOE Orders. Investigations are also performed for various clients to meet the requirements of the Resource Conservation and Recovery Act of 1976 (RCRA) and the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA). National standards including procedures published by the American Society for Testing and Materials (ASTM) and the US Geological Survey were utilized in developing the procedures contained in this manual

  12. Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex

    OpenAIRE

    Kawedia, Jitesh D.; Nieman, Michelle L.; Boivin, Gregory P.; Melvin, James E.; Kikuchi, Ken-Ichiro; Hand, Arthur R.; Lorenz, John N.; Menon, Anil G.

    2007-01-01

    To investigate potential physiological interactions between the transcellular and paracellular pathways of water transport, we asked whether targeted deletion of Aquaporin 5 (AQP5), the major transcellular water transporter in salivary acinar cells, affected paracellular transport of 4-kDa FITC-labeled dextran (FITC-D), which is transported through the paracellular but not the transcellular route. After i.v. injection of FITC-D into either AQP5 wild-type or AQP5−/− mice and saliva collection ...

  13. Barriers to Superfast Water Transport in Carbon Nanotube Membranes

    DEFF Research Database (Denmark)

    Walther, Jens Honore; Ritos, Konstantinos; Cruz-Chu, Eduardo R.

    2013-01-01

    Carbon nanotube (CNT) membranes hold the promise of extraordinary fast water transport for applications such as energy efficient filtration and molecular level drug delivery. However, experiments and computations have reported flow rate enhancements over continuum hydrodynamics that contradict each...... over the continuum predictions. These rates are far below those reported experimentally. The results suggest that the reported superfast water transport rates cannot be attributed to interactions of water with pristine CNTs alone....

  14. Water Transport and the Evolution of CM Parent Bodies

    Science.gov (United States)

    Coker, R.; Cohen, B.

    2014-01-01

    as the effects of relevant chemical reactions, to investigate whether formation of hydrated minerals can occur in the surface and near-surface environments of carbonaceous type asteroids. These models will elucidate how the conditions within the parent body that cause internal aqueous alteration play themselves out at the asteroid's surface. We are using our models to determine whether the heat budget of 20-100-km bodies is sufficient to bring liquid water to the near-surface and cause mineral alteration, or whether additional heat input at the surface (i.e, by impacts) is needed to provide a transient liquid water source for mineral hydration without large- scale liquid water transport.

  15. Composite Transport Model and Water and Solute Transport across Plant Roots: An Update

    Directory of Open Access Journals (Sweden)

    Yangmin X. Kim

    2018-02-01

    Full Text Available The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM. It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots – apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs, which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic. Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle. The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

  16. Geochemical investigation of iron transport into bentonite as steel corrodes

    International Nuclear Information System (INIS)

    Hunter, Fiona; Bate, Fiona; Heath, Tim; Hoch, Andrew

    2007-09-01

    some experiments. Using the experimental data as a guide, a modelling investigation has been carried out. The objectives of the modelling investigation were: To develop a geochemical model of the transport of iron into bentonite based on the clear experimental evidence of the penetration of iron into bentonite. To improve our understanding of the desaturation of the bentonite as water is consumed during the corrosion process and the resultant gas(es) escapes. The production of iron from the corroding source was modelled using a rate of gas evolution that had been fitted. It was shown that ion exchange and surface complexation processes do not provide sufficient sorption to predict the high amount of iron observed in the solid phase. Therefore alternative processes, such as iron-containing mineral formation or mineral transformations, were also suggested to account for the amount of iron observed within the bentonite phase. Magnetite was identified as the most thermodynamically stable solubility limiting phase under the experimental conditions. A one-dimensional transport model was constructed to include all relevant processes. The simulations considered the diffusive transport of Fe 2+ ions away from a corroding source, using the rate of gas evolution resulting from the corrosion process. Ion exchange and surface complexation processes were allowed within the bentonite which would provide sorption of iron onto and within the bentonite solid. The pH was buffered by allowing protonation and deprotonation of the surface sites of the bentonite solid. In addition, saturation of iron-containing minerals was permitted. The base case model suggests that about 4.4 wt % of iron could form in the bentonite if the formation of magnetite was allowed. However, the maximum theoretical amount of iron available from the source term is limited to 4.5 wt % of iron by the cumulative gas evolution rate, which is lower than the observed amount of iron in the bulk bentonite (6.6 wt %). A

  17. Effect of sunlight, transport and storage vessels on drinking water ...

    African Journals Online (AJOL)

    The objective was to evaluate the effect of sunlight, transport and storage vessels on drinking water quality in rural Ghana with the aim of reducing the high demand for fuel wood in the household treatment of water. Well water was exposed for 6h to direct natural sunlight in aluminium, iron, and plastic receptacles and ...

  18. Radiotracer investigations for sediment transport in ports of India

    International Nuclear Information System (INIS)

    Pant, H.J.; Sharma, V.K.; Goswami, Sunil; Singh, Gursharan

    2013-01-01

    The knowledge of mixing and transport of sediments in coastal region is of vital importance for evaluating suitability of dumping site for dredged sediments produced during maintenance of shipping channels, expansion of existing projects and construction of new projects. Gamma-emitting radiotracers are commonly used for investigation of movement of sediments on seabed using Scandium-46 (scandium glass powder) as radiotracer. The radiotracer is injected on seabed at a desired location and its movement followed over a period of time using waterproof NaI(Tl) scintillation detectors. The recorded data is analyzed to obtain transport parameters and utilized for assessing the suitability of the dumping sites and optimization of the dredging operations. About 70 large-scale investigations have been carried out in different ports in India leading to significant economical benefits to the Ports. Present paper discusses various aspects of the radiotracer technique for sediment transport, methodology of data analysis and a specific case study. (author)

  19. Water flow and solute transport in floating fen root mats

    Science.gov (United States)

    Stofberg, Sija F.; EATM van der Zee, Sjoerd

    2015-04-01

    Floating fens are valuable wetlands, found in North-Western Europe, that are formed by floating root mats when old turf ponds are colonized by plants. These terrestrialization ecosystems are known for their biodiversity and the presence of rare plant species, and the root mats reveal different vegetation zones at a small scale. The vegetation zones are a result of strong gradients in abiotic conditions, including groundwater dynamics, nutrients and pH. To prevent irreversible drought effects such as land subsidence and mineralization of peat, water management involves import of water from elsewhere to maintain constant surface water levels. Imported water may have elevated levels of salinity during dry summers, and salt exposure may threaten the vegetation. To assess the risk of exposure of the rare plant species to salinity, the hydrology of such root mats must be understood. Physical properties of root mats have scarcely been investigated. We have measured soil characteristics, hydraulic conductivity, vertical root mat movement and groundwater dynamics in a floating root mat in the nature reserve Nieuwkoopse Plassen, in the Netherlands. The root mat mostly consists of roots and organic material, in which the soil has a high saturated water content, and strongly varies in its stage of decomposition. We have found a distinct negative correlation between degree of decomposition and hydraulic conductivity, similar to observations for bogs in the literature. Our results show that the relatively young, thin edge of the root mat that colonizes the surface water has a high hydraulic conductivity and floats in the surface water, resulting in very small groundwater fluctuations within the root mat. The older part of the root mat, that is connected to the deeper peat layers is hydrologically more isolated and the material has a lower conductivity. Here, the groundwater fluctuates strongly with atmospheric forcing. The zones of hydraulic properties and vegetation, appear to

  20. Quantification of osmotic water transport in vivo using fluorescent albumin.

    Science.gov (United States)

    Morelle, Johann; Sow, Amadou; Vertommen, Didier; Jamar, François; Rippe, Bengt; Devuyst, Olivier

    2014-10-15

    Osmotic water transport across the peritoneal membrane is applied during peritoneal dialysis to remove the excess water accumulated in patients with end-stage renal disease. The discovery of aquaporin water channels and the generation of transgenic animals have stressed the need for novel and accurate methods to unravel molecular mechanisms of water permeability in vivo. Here, we describe the use of fluorescently labeled albumin as a reliable indicator of osmotic water transport across the peritoneal membrane in a well-established mouse model of peritoneal dialysis. After detailed evaluation of intraperitoneal tracer mass kinetics, the technique was validated against direct volumetry, considered as the gold standard. The pH-insensitive dye Alexa Fluor 555-albumin was applied to quantify osmotic water transport across the mouse peritoneal membrane resulting from modulating dialysate osmolality and genetic silencing of the water channel aquaporin-1 (AQP1). Quantification of osmotic water transport using Alexa Fluor 555-albumin closely correlated with direct volumetry and with estimations based on radioiodinated ((125)I) serum albumin (RISA). The low intraperitoneal pressure probably accounts for the negligible disappearance of the tracer from the peritoneal cavity in this model. Taken together, these data demonstrate the appropriateness of pH-insensitive Alexa Fluor 555-albumin as a practical and reliable intraperitoneal volume tracer to quantify osmotic water transport in vivo. Copyright © 2014 the American Physiological Society.

  1. Transport Phenomena of Water in Molecular Fluidic Channels

    Science.gov (United States)

    Vo, Truong Quoc; Kim, Bohung

    2016-09-01

    In molecular-level fluidic transport, where the discrete characteristics of a molecular system are not negligible (in contrast to a continuum description), the response of the molecular water system might still be similar to the continuum description if the time and ensemble averages satisfy the ergodic hypothesis and the scale of the average is enough to recover the classical thermodynamic properties. However, even in such cases, the continuum description breaks down on the material interfaces. In short, molecular-level liquid flows exhibit substantially different physics from classical fluid transport theories because of (i) the interface/surface force field, (ii) thermal/velocity slip, (iii) the discreteness of fluid molecules at the interface and (iv) local viscosity. Therefore, in this study, we present the result of our investigations using molecular dynamics (MD) simulations with continuum-based energy equations and check the validity and limitations of the continuum hypothesis. Our study shows that when the continuum description is subjected to the proper treatment of the interface effects via modified boundary conditions, the so-called continuum-based modified-analytical solutions, they can adequately predict nanoscale fluid transport phenomena. The findings in this work have broad effects in overcoming current limitations in modeling/predicting the fluid behaviors of molecular fluidic devices.

  2. Investigations on transport and storage of high ion beam intensities

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ninad Shrikrishna

    2009-08-25

    In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson's equation. Further simulations were performed to study the self field effects on beam transport. Experiments were performed to compare the simulation results and gain practical experience. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He{sup +} and mixed p, H{sup 2+}, H{sup 3+} beams were analyzed. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was

  3. Investigations on transport and storage of high ion beam intensities

    International Nuclear Information System (INIS)

    Joshi, Ninad Shrikrishna

    2009-01-01

    In the framework of this thesis the intense low energy ion beam transport was investigated. Especially, the beam transport in toroidal magnetic field configurations was discussed, as it may allow the accumulation of high intensive beams in the future. One of the specific tasks is to design an injection system that can be used for the proposed low energy accumulator ring. A simulation code (TBT) was written to describe the particle motion in curved segments. Particle in Cell techniques were utilized to simulate a multi particle dynamics. A possibility of reading an external data file was made available so that a measured distribution can be used to compare simulation results with measured ones. A second order cloud in cell method was used to calculate charge density and in turn to solve Poisson's equation. Further simulations were performed to study the self field effects on beam transport. Experiments were performed to compare the simulation results and gain practical experience. The preparatory experiments consisted of building and characterization of the ion source in a first step. Along with the momentum spectrometer and emittance scanner the beam properties were studied. Low mass ion beams He + and mixed p, H 2+ , H 3+ beams were analyzed. In the second stage, beams were transported through a solenoid and the phase space distribution was measured as a function of the magnetic field for different beam energies. The phase-space as distributions measured in a first stage were simulated backward and then again forward transported through the solenoid. The simulated results were then compared with the measured distribution. The LINTRA transport program was used. The phase-space distribution was further simulated for transport experiments in a toroidal magnetic field. The transport program that was used to simulate the beam in the toroid was also used to design the injection system. The injection system with its special field configurations was designed to perform

  4. Studying Drinking Water Quality and its Change During Transportation through Samara Water-Supply Facilities

    Science.gov (United States)

    Kichigin, V. I.; Egorova, Y. A.; Nesterenko, O. I.

    2017-11-01

    The paper investigates changes in water physico-chemical composition and its physical indicators through ζ-potential in residential buildings in eight administrative districts of Samara. The results are processed by the methods of mathematical statistics and presented at the 0.05 level of importance. The sampling points for water in the city districts were chosen with the aid of random numbers tables. It was determined that the quality of drinking water was stable and consistent with the existing standards in Zheleznodorozhniy, Samarskiy, Leninskiy, Octyabrskiy, Kirovsliy, Sovetskiy and Promyshlenniy districts of Samara. The following indicators were taken into account: pH, colour, turbidity, alkalinity, general rigidity, content of ions Ca2 +, Mg2 +. It was also established that drinking water in Kuibyshevskiy district (with all other excellent indicators) had increased mineralization due to the natural hydrological conditions of the water inlet. Some change in the size of zeta-potential of the water was detected during its transportation through the existing water-supplying networks of the city. It was shown that the link between zeta-potential and various kinds of contamination in drinking water is underexplored and requires further detailed study.

  5. Thermodynamics of transport through the ammonium transporter Amt-1 investigated with free energy calculations.

    Science.gov (United States)

    Ullmann, R Thomas; Andrade, Susana L A; Ullmann, G Matthias

    2012-08-16

    Amt-1 from Archaeoglobus fulgidus (AfAmt-1) belongs to the Amt/Rh family of ammonium/ammonia transporting membrane proteins. The transport mode and the precise microscopic permeation mechanism utilized by these proteins are intensely debated. Open questions concern the identity of the transported substrate (ammonia and/or ammonium) and whether the transport is passive or active. To address these questions, we studied the overall thermodynamics of the different transport modes as a function of the environmental conditions. Then, we investigated the thermodynamics of the underlying microscopic transport mechanisms with free energy calculations within a continuum electrostatics model. The formalism developed for this purpose is of general utility in the calculation of binding free energies for ligands with multiple protonation forms or other binding forms. The results of our calculations are compared to the available experimental and theoretical data on Amt/Rh proteins and discussed in light of the current knowledge on the physiological conditions experienced by microorganisms and plants. We found that microscopic models of electroneutral and electrogenic transport modes are in principle thermodynamically viable. However, only the electrogenic variants have a net thermodynamic driving force under the physiological conditions experienced by microorganisms and plants. Thus, the transport mechanism of AfAmt-1 is most likely electrogenic.

  6. Investigation of electronic transport properties of some liquid transition metals

    Science.gov (United States)

    Patel, H. P.; Sonvane, Y. A.; Thakor, P. B.

    2018-04-01

    We investigated electronic transport properties of some liquid transition metals (V, Cr, Mn, Fe, Co and Pt) using Ziman formalism. Our parameter free model potential which is realized on ionic and atomic radius has been incorporated with the Hard Sphere Yukawa (HSY) reference system to study the electronic transport properties like electrical resistivity (ρ), thermal conductivity (σ) and thermo electrical power (Q). The screening effect on aforesaid properties has been studied by using different screening functions. The correlations of our results and others data with in addition experimental values are profoundly promising to the researchers working in this field. Also, we conclude that our newly constructed parameter free model potential is capable to explain the aforesaid electronic transport properties.

  7. Modeling of water transport through the membrane electrode assembly for direct methanol fuel cells

    Science.gov (United States)

    Xu, C.; Zhao, T. S.; Yang, W. W.

    In this work, a one-dimensional, isothermal two-phase mass transport model is developed to investigate the water transport through the membrane electrode assembly (MEA) for liquid-feed direct methanol fuel cells (DMFCs). The liquid (methanol-water solution) and gas (carbon dioxide gas, methanol vapor and water vapor) two-phase mass transport in the porous anode and cathode is formulated based on classical multiphase flow theory in porous media. In the anode and cathode catalyst layers, the simultaneous three-phase (liquid and vapor in pores as well as dissolved phase in the electrolyte) water transport is considered and the phase exchange of water is modeled with finite-rate interfacial exchanges between different phases. This model enables quantification of the water flux corresponding to each of the three water transport mechanisms through the membrane for DMFCs, such as diffusion, electro-osmotic drag, and convection. Hence, with this model, the effects of MEA design parameters on water crossover and cell performance under various operating conditions can be numerically investigated.

  8. Unstirred Water Layers and the Kinetics of Organic Cation Transport

    Science.gov (United States)

    Shibayama, Takahiro; Morales, Mark; Zhang, Xiaohong; Martinez, Lucy; Berteloot, Alfred; Secomb, Timothy W.; Wright, Stephen H.

    2015-01-01

    Purpose Unstirred water layers (UWLs) present an unavoidable complication in the measurement of transport kinetics in cultured cells and the high rates of transport achieved by overexpressing heterologous transporters exacerbate the UWL effect. This study examined the correlation between measured Jmax and Kt values and the effect of manipulating UWL thickness or transport Jmax on the accuracy of experimentally determined kinetics of the multidrug transporters, OCT2 and MATE1. Methods Transport of TEA and MPP was measured in CHO cells that stably expressed human OCT2 or MATE1. UWL thickness was manipulated by vigorous reciprocal shaking. Several methods were used to manipulate maximal transport rates. Results Vigorous stirring stimulated uptake of OCT2-mediated transport by decreasing apparent Kt (Ktapp) values. Systematic reduction in transport rates was correlated with reduction in Ktapp values. The slope of these relationships indicated a 1500 µm UWL in multiwell plates. Reducing the influence of UWLs (by decreasing either their thickness or the Jmax of substrate transport) reduced Ktapp by 2-fold to >10-fold. Conclusions Failure to take into account the presence of UWLs in experiments using cultured cells to measure transport kinetics can result in significant underestimates of the affinity of multidrug transporters for substrates. PMID:25791216

  9. Water footprint of U.S. transportation fuels.

    Science.gov (United States)

    Scown, Corinne D; Horvath, Arpad; McKone, Thomas E

    2011-04-01

    In the modern global economy, water and energy are fundamentally connected. Water already plays a major role in electricity generation and, with biofuels and electricity poised to gain a significant share of the transportation fuel market, water will become significantly more important for transportation energy as well. This research provides insight into the potential changes in water use resulting from increased biofuel or electricity production for transportation energy, as well as the greenhouse gas and freshwater implications. It is shown that when characterizing the water impact of transportation energy, incorporating indirect water use and defensible allocation techniques have a major impact on the final results, with anywhere between an 82% increase and a 250% decrease in the water footprint if evaporative losses from hydroelectric power are excluded. The greenhouse gas impact results indicate that placing cellulosic biorefineries in areas where water must be supplied using alternative means, such as desalination, wastewater recycling, or importation can increase the fuel's total greenhouse gas footprint by up to 47%. The results also show that the production of ethanol and petroleum fuels burden already overpumped aquifers, whereas electricity production is far less dependent on groundwater.

  10. 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.…

  11. Deep update with new water transport cost model

    International Nuclear Information System (INIS)

    Khamis, I.; Ibrahim, A.H.A.D.; Suleiman, S.

    2007-01-01

    DEEP 3.11 is a new version of DEEP which is capable to calculate the water transport cost in any place, with acceptable accuracy. The user needs only to specify water flow or the capacity, pipeline length and elevation of sites against sea level or difference in elevation of the beginning and end of the pipeline routs

  12. Water vapor and Gas Transport through Polymeric Membranes

    NARCIS (Netherlands)

    Metz, S.J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

  13. Investigative studies on water contamination in Bangladesh. Primary treatment of water samples at the sampling site

    International Nuclear Information System (INIS)

    Sera, K.; Islam, Md. Shafiqul; Takatsuji, T.; Nakamura, T.; Goto, S.; Takahashi, C.; Saitoh, Y.

    2010-01-01

    Arsenic concentration in 13 well waters, 9 pond waters, 10 agricultural waters and a coconut juice taken in Comilla district, Bangladesh, where the problem of arsenic pollution is the most severe, was investigated. High-level arsenic is detected even in the well water which has been kept drinking by the people. Relatively high arsenic concentration was detected for some pond and farm waters even though the sampling was performed just after the rainy season and the waters were expected to be highly diluted. Clear relationship was observed in elemental compositions between the pond water and the coconut juice collected at the edge of the water. These results are expected to become the basic information for evaluating the risk of individual food such as cultured fishes, shrimps and farm products, and for controlling total intakes of arsenic. In order to solve the problem of transportation of water samples internationally, a simple method of target preparation performed at the sampling site was established and its validity was confirmed. All targets were prepared at the sampling sites in this study on the basis of this method. (author)

  14. Investigation of electron beam transport in a helical undulator

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y.U.; Lee, B.C.; Kim, S.K. [Korea Atomic Energy Research Institute, Taejon (Korea, Democratic People`s Republic of)] [and others

    1995-12-31

    Lossless transport of electrons through the undulator is essential for CW operation of the FELs driven by recirculating electrostatic accelerators. We calculate the transport ratio of an electron beam in a helical undulator by using a 3-D simulation code and compare the results with the experimental results. The energy and the current of the electron beam are 400 keV and 2 A, respectively. The 3-D distribution of the magnetic field of a practical permanent-magnet helical undulator is measured and is used in the calculations. The major parameters of the undutlator are : period = 32 mm, number of periods = 20, number of periods in adiabatic region = 3.5, magnetic field strength = 1.3 kG. The transport ratio is very sensitive to the injection condition of the electron beam such as the emittance, the diameter, the divergence, etc.. The injection motion is varied in the experiments by changing the e-gun voltage or the field strength of the focusing magnet located at the entrance of the undulator. It is confirmed experimentally and with simulations that most of the beam loss occurs at the adiabatic region of the undulator regardless of the length of the adiabatic region The effect of axial guiding magnetic field on the beam finish is investigated. According to the simulations, the increase of the strength of axial magnetic field from 0 to 1 kG results in the increase of the transport ratio from 15 % to 95%.

  15. The effect of inhomogeneous compression on water transport in the cathode of a PEM fuel cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2011-01-01

    layer, micro-porous layer and catalyst layer, excluding the membrane and anode. In the porous media liquid water transport is described by the capillary pressure gradient, momentum loss via the Darcy-Forchheimer equation and mass transfer between phases by a non-equilibrium phase change model....... Furthermore, the presence of irreducible liquid water is taken into account. In order to account for compression, porous media morphology variations are specified based on the GDL through-plane strain and intrusion which are stated as a function of compression. These morphology variations affect gas...... and liquid water transport, and hence liquid water distribution and the risk of blocking active sites. Hence, water transport is studied under GDL compression, in order to investigate the qualitative effects. Two simulation cases are compared; one with and one without compression....

  16. Functional characterization of water transport and cellular localization of three aquaporin paralogs in the salmonid intestine

    DEFF Research Database (Denmark)

    Madsen, Steffen S; Olesen, Jesper H; Bedal, Konstanze

    2011-01-01

    Intestinal water absorption is greatly enhanced in salmonids upon acclimation from freshwater (FW) to seawater (SW); however, the molecular mechanism for water transport is unknown. We conducted a pharmacological characterization of water absorption in the rainbow trout intestine along with an in......Intestinal water absorption is greatly enhanced in salmonids upon acclimation from freshwater (FW) to seawater (SW); however, the molecular mechanism for water transport is unknown. We conducted a pharmacological characterization of water absorption in the rainbow trout intestine along...... with an investigation of the distribution and cellular localization of three aquaporins (Aqp1aa, -1ab, and -8ab) in pyloric caeca, middle (M), and posterior (P) intestine of the Atlantic salmon. In vitro iso-osmotic water absorption (J(v)) was higher in SW than FW-trout and was inhibited by (mmol L(-1)): 0.1 KCN (41......%), 0.1 ouabain (72%), and 0.1 bumetanide (82%) suggesting that active transport, Na(+), K(+)-ATPase and Na(+), K(+), 2Cl(-)-co-transport are involved in establishing the driving gradient for water transport. J(v) was also inhibited by 1 mmol L(-1) HgCl(2), serosally (23% in M and 44% in P), mucosally...

  17. Kinetics of proton transport in water

    DEFF Research Database (Denmark)

    Kornyshev, A.A.; Kuznetsov, A.M.; Spohr, E.

    2003-01-01

    +), (ii) proton transfer from hydronium to a neighboring water molecule, and (iii) structural diffusion of the Zundel complex (H5O2+), the processes all controlled by orientational fluctuations or hydrogen bond breaking in neighboring hydration shells. Spontaneous conversion of excess proton states...

  18. Free water transport, small pore transport and the osmotic pressure gradient.

    Science.gov (United States)

    Parikova, Alena; Smit, Watske; Zweers, Machteld M; Struijk, Dirk G; Krediet, Raymond T

    2008-07-01

    Water transport in peritoneal dialysis (PD) patients occurs through the small pores and water channels, the latter allowing free water transport (FWT). The osmotic gradient is known to be one of the major determinants of water transport. The objective of the study was to analyse the relation between each transport route and the osmotic gradient. The 4-h standard peritoneal permeability analyses of 80 stable PD patients were studied. Small pore transport (SPT) was calculated based on the transported amount of sodium. FWT was calculated by subtracting SPT from transcapillary ultrafiltration (TCUF). Water transport rates were determined. The osmotic gradient was calculated. The slope of the relation between FWT rate and osmotic gradient (slope(FWT)), and the elimination constant (K(e)) of the exponential relation between SPT rate and osmotic gradient (K(SPT)) were calculated for every patient. The FWT rate was related to the osmotic gradient (P = 0.001). A similar correlation was also found between the SPT rate and osmotic gradient when fitted exponentially (P = 0.005). The rates of FWT decreased significantly between each time point during the whole dwell. The SPT rates decreased significantly within the first half of the dwell and levelled off thereafter. No correlations were found between the slope(FWT), K(SPT) and PD duration. The slope(FWT) of the relationship between the FWT and the osmotic gradient is an indirect measurement of the amount of functioning water channels. Similarly, the K(SPT) value represents the number of functioning small pores. The absence of a relationship of these parameters with the duration of PD suggests opposing mechanisms, for instance a lower number of functioning pores in combination with an increased vascular surface area. Conclusion. The curves of the relationship between FWR, SPT and OG support the assumption that FWR is much more dependent on the OG than SPT. Non-osmotic determinants are likely to be important in small pore fluid

  19. Numerical and experimental investigation of UV disinfection for water treatment

    International Nuclear Information System (INIS)

    Li, H.Y.; Osman, H.; Kang, C.W.; Ba, T.

    2017-01-01

    Highlights: • UV irradiation for water treatment is numerically and experimentally investigated. • Fluence rate E increases exponentially with the increase of UVT. • UV dose distribution moves to a high range with increase of UVT and lamp power. • A linear relationship is observed between fluence rate E and average UV dose D ave . • D ave decreases with the increase of UVT and fluid flow rate. - Abstract: Disinfection by ultraviolet (UV) for water treatment in a UV reactor is numerically and experimentally investigated in this paper. The flow of water, UV radiation transportation as well as microorganism particle trajectories in the UV reactor is simulated. The effects of different parameters including UV transmittance (UVT), lamp power and water flow rate on the UV dose distribution and average UV dose are studied. The UV reactor performance in terms of average UV dose under these parameters is analysed. Comparisons are made between experiments and simulations on the average UV dose and reasonable agreement is achieved. The results show that the fluence rate increases exponentially with the increase of UVT. The UV dose distribution profiles moves to a high range of UV dose with the increase of UVT and lamp power. The increase of water flow rate reduces the average exposure time of microorganism particles to the UV light, resulting in the shifting of UV dose distribution to a low range of UV dose. A linear relationship is observed between fluence rate and the average UV dose. The average UV dose increases with the increase of lamp power while it decreases with the increase of UVT and water flow rate.

  20. Investigating the improver mechanisms of agricultural water ...

    African Journals Online (AJOL)

    The findings revealed that increase of efficient monitoring of government on surface water resources and also implementation of watershed projects are the main mechanisms of surface water and underground water management in utilization and about the management of agricultural water transmission, covering the ...

  1. Effect of hydrophilic defects on water transport in MFI zeolites.

    Science.gov (United States)

    Humplik, Thomas; Raj, Rishi; Maroo, Shalabh C; Laoui, Tahar; Wang, Evelyn N

    2014-06-10

    The subnanometer pore structure of zeolites and other microporous materials has been proposed to act as a molecular sieve for various water separation technologies. However, due to the increased interaction between the solid and water in these nanoconfined spaces, it is unclear which type of interface, be it hydrophilic or hydrophobic, offers an advantageous medium for enhancing transport properties. In this work, we probe the role of hydrophilic defects on the transport of water inside the microporous hydrophobic MFI zeolite pore structure via combined sorption and high-pressure infiltration experiments. While the inclusion of defects was observed to increase the amount of water within the zeolite pore network by up to 7 times at the saturation pressure, the diffusivity of this infiltrated water was lowered by up to 2 orders of magnitude in comparison to that of water within the nearly defect-free hydrophobic MFI zeolite. Subsequently, the permeability of water within the more defective MFI zeolite was an order of magnitude lower than that of the nearly defect-free zeolite. The results from these experiments suggest that the intrinsic hydrophobic pore structure of MFI zeolites can facilitate faster water transport due to the decreased attraction between the water and the defect-free surface. While the strong attraction of water to the defects allows for water to infiltrate the porous network at lower pressures, the results suggest that this strong attraction decreases the mobility of the infiltrated water. The insights gained from this study can be utilized to improve the design of future membranes for water desalination and other separation techniques.

  2. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  3. Biofilm bacterial communities in urban drinking water distribution systems transporting waters with different purification strategies.

    Science.gov (United States)

    Wu, Huiting; Zhang, Jingxu; Mi, Zilong; Xie, Shuguang; Chen, Chao; Zhang, Xiaojian

    2015-02-01

    Biofilm formation in drinking water distribution systems (DWDS) has many adverse consequences. Knowledge of microbial community structure of DWDS biofilm can aid in the design of an effective control strategy. However, biofilm bacterial community in real DWDS and the impact of drinking water purification strategy remain unclear. The present study investigated the composition and diversity of biofilm bacterial community in real DWDSs transporting waters with different purification strategies (conventional treatment and integrated treatment). High-throughput Illumina MiSeq sequencing analysis illustrated a large shift in the diversity and structure of biofilm bacterial community in real DWDS. Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Nitrospirae, and Cyanobacteria were the major components of biofilm bacterial community. Proteobacteria (mainly Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria) predominated in each DWDS biofilm, but the compositions of the dominant proteobacterial classes and genera and their proportions varied among biofilm samples. Drinking water purification strategy could shape DWDS biofilm bacterial community. Moreover, Pearson's correlation analysis indicated that Actinobacteria was positively correlated with the levels of total alkalinity and dissolved organic carbon in tap water, while Firmicutes had a significant positive correlation with nitrite nitrogen.

  4. Numerical investigation of nanoparticles transport in anisotropic porous media

    KAUST Repository

    Salama, Amgad

    2015-07-13

    In this work the problem related to the transport of nanoparticles in anisotropic porous media is investigated numerically using the multipoint flux approximation. Anisotropy of porous media properties are an essential feature that exist almost everywhere in subsurface formations. In anisotropic media, the flux and the pressure gradient vectors are no longer collinear and therefore interesting patterns emerge. The transport of nanoparticles in subsurface formations is affected by several complex processes including surface charges, heterogeneity of nanoparticles and soil grain collectors, interfacial dynamics of double-layer and many others. We use the framework of the theory of filtration in this investigation. Processes like particles deposition, entrapment, as well as detachment are accounted for. From the numerical methods point of view, traditional two-point flux finite difference approximation cannot handle anisotropy of media properties. Therefore, in this work we use the multipoint flux approximation (MPFA). In this technique, the flux components are affected by more neighboring points as opposed to the mere two points that are usually used in traditional finite volume methods. We also use the experimenting pressure field approach which automatically constructs the global system of equations by solving multitude of local problems. This approach facilitates to a large extent the construction of the global system. A set of numerical examples is considered involving two-dimensional rectangular domain. A source of nanoparticles is inserted in the middle of the anisotropic layer. We investigate the effects of both anisotropy angle and anisotropy ratio on the transport of nanoparticles in saturated porous media. It is found that the concentration plume and porosity contours follow closely the principal direction of anisotropy of permeability of the central domain.

  5. Online estimation of radionuclide transportation in water environment

    International Nuclear Information System (INIS)

    Yi-Jing Zhang; Li-Sheng Hu

    2017-01-01

    Transportation evaluation of the radionuclide waste discharged from nuclear power plants is an essential licensing issue, especially for inland sites. Basically, the dynamics of radionuclide transportation are nonlinear and time-varying. Motivated by its time-consuming computation, the work proposed an online estimation method for the radionuclide waste in water surface. After extracting the nonlinearity of factors influencing radionuclide transportation, the method utilizes transfer function and generalized autoregressive conditional heteroskedasticity models to perform deterministic and probabilistic estimations. It turns out that, the resulting predictions show high accuracy and can optimize the online discharge management of radioactive waste for nuclear power plants. (author)

  6. Modeling water transport in liquid feed direct methanol fuel cells

    Science.gov (United States)

    Liu, Wenpeng; Wang, Chao-Yang

    Proper water management in direct methanol fuel cells (DMFCs) is very critical and complicated because of many interacting physicochemical phenomena. Among these, the liquid saturation in the cathode side is believed to have a very strong effect on water crossover through the membrane, a key parameter to determine water balance between the anode and cathode. In this paper, based on an interfacial liquid coverage model implemented in a three-dimensional (3D) two-phase DMFC model, the liquid saturation variations in the cathode are examined in detail and their effects on the net water transport coefficient through the membrane discussed.

  7. A transportable system for radioactivity contaminated water treatment

    International Nuclear Information System (INIS)

    2013-01-01

    Contaminated water treatment system called SARRY for retrieval and recovery of water in operation at the site of Fukushima Daiichi Nuclear Power Plant since August 2011 has been modified by compacting the system size to develop a mobile system SARRY-Aqua that can process Cs-contaminated water (one ton/hour) to the level of 10 Bq/kg. Installing the system in a small container with dimensions conforming to the international standards facilitates transportation by truck and enables the contaminated water treatment occurring in a variety of locations. (S. Ohno)

  8. Impact of carbonation on water transport properties of cementitious materials

    International Nuclear Information System (INIS)

    Auroy, Martin

    2014-01-01

    Carbonation is a very well-known cementitious materials pathology. It is the major cause of reinforced concrete structures degradation. It leads to rebar corrosion and consequent concrete cover cracking. In the framework of radioactive waste management, cement-based materials used as building materials for structures or containers would be simultaneously submitted to drying and atmospheric carbonation. Although scientific literature regarding carbonating is vast, it is clearly lacking information about the influence of carbonation on water transport properties. This work then aimed at studying and understanding the change in water transport properties induced by carbonation. Simultaneously, the representativeness of accelerated carbonation (in the laboratory) was also studied. (author) [fr

  9. Moisture transport through water-impermeable concrete elements

    International Nuclear Information System (INIS)

    Rahn, Axel C.; Friedrich, Matthias; Rieger, Stephan

    2005-01-01

    Frequently during planning construction elements made of water-impermeable concrete it is disregarded that they are a matter of design, not of material. The article comments on different ways of moisture transport in water-impermeable concrete elements and explains the state of the knowledge. It goes into the German guideline ''WU-Richtlinie'' published by the German Committee of Reinforced Concrete (DAfStb) and discusses the consideration of moisture transport for the specification of the guideline requirements. Additional possible measures to be taken in cases of high-quality classification of design utilization in accordance with the guideline are described. (Abstract Copyright [2005], Wiley Periodicals, Inc.) [de

  10. Modeling and Diagnostics of Fuel Cell Porous Media for Improving Water Transport

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Jeff; M' edici, Ezequiel

    2011-07-01

    When a fuel cell is operating at high current density, water accumulation is a significant cause of performance and component degradation. Investigating the water transport inside the fuel cell is a challenging task due to opacity of the components, the randomness of the porous materials, and the difficulty in gain access to the interior for measurement due to the small dimensions of components. Numerical simulation can provide a good insight of the evolution of the water transport under different working condition. However, the validation of those simulations is remains an issue due the same experimental obstacles associated with in-situ measurements. The discussion herein will focus on pore-network modeling of the water transport on the PTL and the insights gained from simulations as well as in the validation technique. The implications of a recently published criterion to characterize PTL, based on percolation theory, and validate numerical simulation are discussed.

  11. Arctic water tracks retain phosphorus and transport ammonium

    Science.gov (United States)

    Harms, T.; Cook, C. L.; Wlostowski, A. N.; Godsey, S.; Gooseff, M. N.

    2017-12-01

    Hydrologic flowpaths propagate biogeochemical signals among adjacent ecosystems, but reactions may attenuate signals by retaining, removing, or transforming dissolved and suspended materials. The theory of nutrient spiraling describes these simultaneous reaction and transport processes, but its application has been limited to stream channels. We applied nutrient spiraling theory to water tracks, zero-order channels draining Arctic hillslopes that contain perennially saturated soils and flow at the surface either perennially or in response to precipitation. In the Arctic, experimental warming results in increased availability of nitrogen, the limiting nutrient for hillslope vegetation at the study site, which may be delivered to aquatic ecosystems by water tracks. Increased intensity of rain events, deeper snowpack, earlier snowmelt, and increasing thaw depth resulting from climate change might support increased transport of nutrients, but the reactive capacity of hillslope flowpaths, including sorption and uptake by plants and microbes, could counter transport to regulate solute flux. Characteristics of flowpaths might influence the opportunity for reaction, where slower flowpaths increase the contact time between solutes and soils or roots. We measured nitrogen and phosphorus uptake and transient storage of water tracks through the growing season and found that water tracks retain inorganic phosphorus, but transport ammonium. Nutrient uptake was unrelated to transient storage, suggesting high capacity for nutrient retention by shallow organic soils and vegetation. These observations indicate that increased availability of ammonium, the biogeochemical signal of warming tundra, is propagated by hillslope flowpaths, whereas water tracks attenuate delivery of phosphorus to aquatic ecosystems, where its availability typically limits production.

  12. Water magnetization and phosphorus transport parameters in the soil

    OpenAIRE

    Generoso, Tarcila N.; Martinez, Mauro A.; Rocha, Genelício C.; Hamakawa, Paulo J.

    2017-01-01

    ABSTRACT There are scientific studies describing changes in properties of the water when subjected to the action of a magnetic field, which may favor the availability of some nutrients in the soil solution. Some nutrients, although they are essential to the process of crop development, can be sources of pollution for watercourses and soil. The aim of this study was to evaluate the effect of water magnetization on transport parameters of the phosphate ion in a Red Latosol (RL) and in a Quartza...

  13. CFD Model of Water Droplet Transport for ISS Hygiene Activity

    Science.gov (United States)

    Son, Chang H.

    2011-01-01

    The goal of the study is to assess the impacts of free water propagation in the Waste and Hygiene Compartment (WHC). Free water can be generated inside the WHC in small quantities due to crew hygiene activity. To mitigate potential impact of free water in Node 3 cabin the WHC doorway is enclosed by a waterproof bump-out, Kabin, with openings at the top and bottom. At the overhead side of the rack, there is a screen that prevents large drops of water from exiting. However, as the avionics fan in the WHC causes airflow toward the deck side of the rack, small quantities of free water may exit at the bottom of the Kabin. A Computational Fluid Dynamics (CFD) analysis of Node 3 cabin airflow made possible to identify the paths of water transport. The Node 3 airflow was computed for several ventilation scenarios. To simulate the droplet transport the Lagrangian discrete phase approach was used. Various initial droplet distributions were considered in the study. The droplet diameter was varied in the range of 2-20 mm. The results of the computations showed that most of the drops fall to the rack surface not far from the WHC curtain. The probability of the droplet transport to the adjacent rack surface with electronic equipment was predicted.

  14. Water transport through tomato roots infected with Meloidogyne incognita.

    NARCIS (Netherlands)

    Dorhout, R.; Gommers, F.J.; Kollöffel, C.

    1991-01-01


    The effect of Meloidogyne incognita on water flow in tomato roots was investigated in rooted split-stem cuttings. Total water flow through infected root parts was significantly lower than through comparable uninfected parts. Total water uptake was correlated with total length of the root

  15. Comparison of a modified peptone water transport medium with two ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-06-07

    Jun 7, 2010 ... A laboratory modified peptone water medium was evaluated alongside Stuart and Amies media for their relative suitability as transport media for aerobic bacteria isolated from wound specimens obtained from Central Hospital, Benin City, Nigeria. The survival rates of isolates from the three media were.

  16. Water Transport in Trees--An Artificial Laboratory Tree

    Science.gov (United States)

    Susman, K.; Razpet, N.; Cepic, M.

    2011-01-01

    Water transport in tall trees is an everyday phenomenon, seldom noticed and not completely understood even by scientists. As a topic of current research in plant physiology it has several advantages for presentation within school physics lectures: it is interdisciplinary and clearly shows the connection between physics and biology; the…

  17. Comparison of a modified peptone water transport medium with two ...

    African Journals Online (AJOL)

    A laboratory modified peptone water medium was evaluated alongside Stuart and Amies media for their relative suitability as transport media for aerobic bacteria isolated from wound specimens obtained from Central Hospital, Benin City, Nigeria. The survival rates of isolates from the three media were assessed ...

  18. Classroom Techniques to Illustrate Water Transport in Plants

    Science.gov (United States)

    Lakrim, Mohamed

    2013-01-01

    The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

  19. Enhanced water transport and salt rejection through hydrophobic zeolite pores

    Science.gov (United States)

    Humplik, Thomas; Lee, Jongho; O’Hern, Sean; Laoui, Tahar; Karnik, Rohit; Wang, Evelyn N.

    2017-12-01

    The potential of improvements to reverse osmosis (RO) desalination by incorporating porous nanostructured materials such as zeolites into the selective layer in the membrane has spurred substantial research efforts over the past decade. However, because of the lack of methods to probe transport across these materials, it is still unclear which pore size or internal surface chemistry is optimal for maximizing permeability and salt rejection. We developed a platform to measure the transport of water and salt across a single layer of zeolite crystals, elucidating the effects of internal wettability on water and salt transport through the ≈5.5 Å pores of MFI zeolites. MFI zeolites with a more hydrophobic (i.e., less attractive) internal surface chemistry facilitated an approximately order of magnitude increase in water permeability compared to more hydrophilic MFI zeolites, while simultaneously fully rejecting both potassium and chlorine ions. However, our results also demonstrated approximately two orders of magnitude lower permeability compared to molecular simulations. This decreased performance suggests that additional transport resistances (such as surface barriers, pore collapse or blockages due to contamination) may be limiting the performance of experimental nanostructured membranes. Nevertheless, the inclusion of hydrophobic sub-nanometer pores into the active layer of RO membranes should improve both the water permeability and salt rejection of future RO membranes (Fasano et al 2016 Nat. Commun. 7 12762).

  20. Measuring Transport of Water Across the Peritoneal Membrane

    Czech Academy of Sciences Publication Activity Database

    Asghar, R. B.; Diskin, A. M.; Španěl, Patrik; Smith, D.; Davies, S. J.

    2003-01-01

    Roč. 64, - (2003), s. 1911-1915 ISSN 0085-2538 R&D Projects: GA ČR GA202/03/0827 Institutional research plan: CEZ:AV0Z4040901 Keywords : deuterium * total body water * solute transport Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.302, year: 2003

  1. Simultaneous transport of water and solutes under transient ...

    Indian Academy of Sciences (India)

    Simultaneous transport of water and solutes under transient unsaturated flow conditions – A case study. B K Purandara. ∗. , N Varadarajan and B Venkatesh. National Institute of Hydrology, Hard Rock Regional Center, Belgaum 590 001, Karnataka, India. ∗ e-mail: purandarabk@yahoo.com. The imbalance between ...

  2. Impacts of transportation infrastructure on storm water and surfaces waters in Chittenden County, Vermont, USA.

    Science.gov (United States)

    2014-06-01

    Transportation infrastructure is a major source of stormwater runoff that can alter hydrology and : contribute significant loading of nutrients, sediment, and other pollutants to surface waters. These : increased loads can contribute to impairment of...

  3. Investigation of water hammer in Globochica HPP

    International Nuclear Information System (INIS)

    Bergant, Anton; Saveski, Vasil; Sijamhodjic, Esad

    2004-01-01

    Water hammer should be one of the key elements of the feasibility and design studies in order to ensure safe operation of the hydroelectric power plant (HPP). The main objective of this paper is to identify critical flow regimes which may cause unacceptable water hammer in a Francis turbine HPP. Water hammer is described by the set of hyperbolic partial differential equations, the continuity equation and the equation of motion. The method of characteristics is used for solving these equations. The water turbine is treated as a boundary condition within the method of characteristics. The paper concludes with water hammer analysis in Globocica HPP, Republic of Macedonia. The system tinder consideration is fitted with two 23 MW Francis turbines. There is a reasonable agreement between the computational is field test results. (Author)

  4. Water transport by the Na+/glucose cotransporter under isotonic conditions

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Klaerke, D A

    1997-01-01

    Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed ...... of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin....

  5. Experimental investigation on heat transport in gravel-sand materials

    DEFF Research Database (Denmark)

    Maureschat, Gerald; Heller, Alfred

    1997-01-01

    in sand-gravel material, the storage media is to be water satured. In this case, handling of such material on site is rather complex. The conduction is highly dependent on the thermal properties of the storage media and so is the overall thermal performance of a storage applying such media. For sandy...... out in a small size experiment. The experiment consists of a highly insulated box filled with two kinds of sand material crossed by a plastic heat pipe. Heat transfer is measured under dry and water satured conditions in a cross-section.The conclusions are clear. To obtain necessary heat conduction......The project is a basic study on the expected thermal behaviour of gravel storage initiated as a part of a research and demonstration gravel storage for seasonal heat storage.The goal of the investigation is to determine the heat transfer between heat pipes and sand-gravel storage media by carrying...

  6. Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

    Science.gov (United States)

    Poindexter, C.; Variano, E. A.

    2010-12-01

    Flow around arrays of cylinders at low and intermediate Reynolds numbers has been studied numerically, analytically and experimentally. Early results demonstrated that at flow around randomly oriented cylinders exhibits reduced turbulent length scales and reduced diffusivity when compared to similarly forced, unimpeded flows (Nepf 1999). While horizontal dispersion in flows through cylinder arrays has received considerable research attention, the case of vertical dispersion of reactive constituents has not. This case is relevant to the vertical transfer of dissolved gases in wetlands with emergent vegetation. We present results showing that the presence of vegetation can significantly enhance vertical transport, including gas transfer across the air-water interface. Specifically, we study a wind-sheared air-water interface in which randomly arrayed cylinders represent emergent vegetation. Wind is one of several processes that may govern physical dispersion of dissolved gases in wetlands. Wind represents the dominant force for gas transfer across the air-water interface in the ocean. Empirical relationships between wind and the gas transfer coefficient, k, have been used to estimate spatial variability of CO2 exchange across the worlds’ oceans. Because wetlands with emergent vegetation are different from oceans, different model of wind effects is needed. We investigated the vertical transport of dissolved oxygen in a scaled wetland model built inside a laboratory tank equipped with an open-ended wind tunnel. Plastic tubing immersed in water to a depth of approximately 40 cm represented emergent vegetation of cylindrical form such as hard-stem bulrush (Schoenoplectus acutus). After partially removing the oxygen from the tank water via reaction with sodium sulfite, we used an optical probe to measure dissolved oxygen at mid-depth as the tank water re-equilibrated with the air above. We used dissolved oxygen time-series for a range of mean wind speeds to estimate the

  7. Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications.

    Science.gov (United States)

    Hajigholizadeh, Mohammad; Melesse, Assefa M; Fuentes, Hector R

    2018-03-14

    The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability.

  8. Erosion and Sediment Transport Modelling in Shallow Waters: A Review on Approaches, Models and Applications

    Science.gov (United States)

    Fuentes, Hector R.

    2018-01-01

    The erosion and sediment transport processes in shallow waters, which are discussed in this paper, begin when water droplets hit the soil surface. The transport mechanism caused by the consequent rainfall-runoff process determines the amount of generated sediment that can be transferred downslope. Many significant studies and models are performed to investigate these processes, which differ in terms of their effecting factors, approaches, inputs and outputs, model structure and the manner that these processes represent. This paper attempts to review the related literature concerning sediment transport modelling in shallow waters. A classification based on the representational processes of the soil erosion and sediment transport models (empirical, conceptual, physical and hybrid) is adopted, and the commonly-used models and their characteristics are listed. This review is expected to be of interest to researchers and soil and water conservation managers who are working on erosion and sediment transport phenomena in shallow waters. The paper format should be helpful for practitioners to identify and generally characterize the types of available models, their strengths and their basic scope of applicability. PMID:29538335

  9. Quantized Water Transport: Ideal Desalination through Graphyne-4 Membrane

    Science.gov (United States)

    Zhu, Chongqin; Li, Hui; Zeng, Xiao Cheng; Wang, E. G.; Meng, Sheng

    2013-01-01

    Graphyne sheet exhibits promising potential for nanoscale desalination to achieve both high water permeability and salt rejection rate. Extensive molecular dynamics simulations on pore-size effects suggest that γ-graphyne-4, with 4 acetylene bonds between two adjacent phenyl rings, has the best performance with 100% salt rejection and an unprecedented water permeability, to our knowledge, of ~13 L/cm2/day/MPa, 3 orders of magnitude higher than prevailing commercial membranes based on reverse osmosis, and ~10 times higher than the state-of-the-art nanoporous graphene. Strikingly, water permeability across graphyne exhibits unexpected nonlinear dependence on the pore size. This counter-intuitive behavior is attributed to the quantized nature of water flow at the nanoscale, which has wide implications in controlling nanoscale water transport and designing highly effective membranes. PMID:24196437

  10. Pentobarbital inhibits glucose uptake, but not water transport by glucose transporter type 3.

    Science.gov (United States)

    Tomioka, Shigemasa; Kaneko, Miyuki; Nakajo, Nobuyoshi

    2012-08-01

    To understand the mechanisms underlying the neuroprotective efficacy of barbiturates, the effect of pentobarbital on glucose uptake and water transport was determined in Xenopus oocytes expressing glucose transporter type 3 (GLUT3). Pentobarbital induced a 50% concentration-dependent inhibition in glucose uptake, but exerted no effect on water transport by GLUT3. Eadie-Hofstee analysis showed that pentobarbital decreased Vmax significantly, but not Km of GLUT3 for 2-deoxy-D-glucose. Although the protein kinase C (PKC) activator significantly decreased glucose uptake by GLUT3, no additive or synergistic interactions were observed between the PKC activator and pentobarbital. Our results suggest that pentobarbital may play an important role in neuroprotection by inhibition of glucose uptake by GLUT3 by a mechanism involving PKC.

  11. The Effect of Inhomogeneous Compression on Water Transport in the Cathode of a Proton Exchange Membrane Fuel Cell

    DEFF Research Database (Denmark)

    Olesen, Anders Christian; Berning, Torsten; Kær, Søren Knudsen

    2012-01-01

    diffusion layer, microporous layer, and catalyst layer, excluding the membrane and anode. In the porous media liquid water transport is described by the capillary pressure gradient, momentum loss via the Darcy-Forchheimer equation, and mass transfer between phases by a nonequilibrium phase change model...... variations affect gas and liquid water transport, and hence liquid water distribution and the risk of blocking active sites. Hence, water transport is studied under GDL compression in order to investigate the qualitative effects. Two simulation cases are compared; one with and one without compression.......A three-dimensional, multicomponent, two-fluid model developed in the commercial CFD package CFX 13 (ANSYS Inc.) is used to investigate the effect of porous media compression on water transport in a proton exchange membrane fuel cell (PEMFC). The PEMFC model only consist of the cathode channel, gas...

  12. Ground-water solute transport modeling using a three-dimensional scaled model

    International Nuclear Information System (INIS)

    Crider, S.S.

    1987-01-01

    Scaled models are used extensively in current hydraulic research on sediment transport and solute dispersion in free surface flows (rivers, estuaries), but are neglected in current ground-water model research. Thus, an investigation was conducted to test the efficacy of a three-dimensional scaled model of solute transport in ground water. No previous results from such a model have been reported. Experiments performed on uniform scaled models indicated that some historical problems (e.g., construction and scaling difficulties; disproportionate capillary rise in model) were partly overcome by using simple model materials (sand, cement and water), by restricting model application to selective classes of problems, and by physically controlling the effect of the model capillary zone. Results from these tests were compared with mathematical models. Model scaling laws were derived for ground-water solute transport and used to build a three-dimensional scaled model of a ground-water tritium plume in a prototype aquifer on the Savannah River Plant near Aiken, South Carolina. Model results compared favorably with field data and with a numerical model. Scaled models are recommended as a useful additional tool for prediction of ground-water solute transport

  13. Neutron imaging of root water uptake, transport and hydraulic redistribution

    Science.gov (United States)

    Warren, J.; Bilheux, H.; Kang, M.; Voisin, S.; Cheng, C.; Horita, J.; Perfect, E.

    2012-12-01

    Knowledge of plant water fluxes is critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolving root water transport dynamics has been a particularly daunting task. Our objectives were to demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within 1-3-week old Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings using neutron imaging. Seedlings were propagated in a growth chamber adjacent to the HFIR CG1 Beam Line at Oak Ridge National Laboratory in cylindrical or plate-like aluminum chambers containing sand. Seedlings were maintained under fairly dry conditions, with water added only to replace daily evapotranspiration. Plants were placed into the high flux cold neutron beam line and injections of H2O or deuterium oxide (D2O) were tracked through the soil and root systems by collecting consecutive CCD radiographs through time. Water fluxes within the root systems were manipulated by cycling on a growth lamp that altered foliar demand for water and thus internal water potential driving forces. 2D and 3D neutron radiography readily illuminated root structure, root growth, and relative plant and soil water content. 2D pulse-chase irrigation experiments with H2O and D2O, which have different neutron cross sections and thus differences in resulting image contrast, successfully allowed observation of uptake and mass flow of water within the root system. After irrigation there was rapid root water uptake from the newly wetted soil, followed by progressive hydraulic redistribution of water through the root systems to roots terminating in dry soil. Water flux within individual roots responded differentially to foliar illumination based on internal water potential gradients. Using 2D radiography, absolute fluxes of H2O or D2O through the system could not be easily determined since neutron attenuation through the sample was dependent on unknown and dynamic magnitudes of both D and H

  14. Structural basis of water-specific transport through the AQP1 water channel

    Science.gov (United States)

    Sui, Haixin; Han, Bong-Gyoon; Lee, John K.; Walian, Peter; Jap, Bing K.

    2001-12-01

    Water channels facilitate the rapid transport of water across cell membranes in response to osmotic gradients. These channels are believed to be involved in many physiological processes that include renal water conservation, neuro-homeostasis, digestion, regulation of body temperature and reproduction. Members of the water channel superfamily have been found in a range of cell types from bacteria to human. In mammals, there are currently 10 families of water channels, referred to as aquaporins (AQP): AQP0-AQP9. Here we report the structure of the aquaporin 1 (AQP1) water channel to 2.2Å resolution. The channel consists of three topological elements, an extracellular and a cytoplasmic vestibule connected by an extended narrow pore or selectivity filter. Within the selectivity filter, four bound waters are localized along three hydrophilic nodes, which punctuate an otherwise extremely hydrophobic pore segment. This unusual combination of a long hydrophobic pore and a minimal number of solute binding sites facilitates rapid water transport. Residues of the constriction region, in particular histidine 182, which is conserved among all known water-specific channels, are critical in establishing water specificity. Our analysis of the AQP1 pore also indicates that the transport of protons through this channel is highly energetically unfavourable.

  15. Development of atmosphere-soil-vegetation model for investigation of radioactive materials transport in terrestrial biosphere

    International Nuclear Information System (INIS)

    Katata, Genki; Nagai, Haruyasu; Zhang, Leiming; Held, Andreas; Serca, Dominique; Klemm, Otto

    2010-01-01

    In order to investigate the transport of radionuclides in the terrestrial biosphere we have developed a one-dimensional numerical model named SOLVEG that predicts the transfer of water, heat, and gaseous and particulate matters in atmosphere-soil-vegetation system. The SOLVEG represents atmosphere, soil, and vegetation as an aggregation of several layers. Basic equations used in the model are solved using the finite difference method. Most of predicted variables are interrelated with the source/sink terms of momentum, water, heat, gases, and particles based on mathematically described biophysical processes in atmosphere, soil and vegetation. The SOLVEG can estimate dry, wet and fog deposition of gaseous and particulate matters at each canopy layer. Performance tests of the SOLVEG with several observational sites were carried out. The SOLVEG predicted the observed temporal changes in water vapor, CO 2 , and ozone fluxes over vegetated surfaces. The SOLVEG also reproduced measured fluxes of fog droplets and of fine aerosols over the forest. (author)

  16. Simplification of Water Distribution Network Simulation by Topological Clustering – Investigation of its Potential Use in Copenhagen's Water Supply Monitoring and Contamination Contingency Plans

    DEFF Research Database (Denmark)

    Kirstein, Jonas Kjeld; Albrechtsen, Hans-Jørgen; Rygaard, Martin

    2014-01-01

    Topological clustering was investigated to simplify a complex water distribution network of Copenhagen, Denmark, into recogniz- able water movement patterns. This made it possible to assess the general transport of the water and to suggest strategic sampling locations. Through a topological analy...

  17. Impact of carbonation on the durability of cementitious materials: water transport properties characterization

    Directory of Open Access Journals (Sweden)

    Le Bescop P.

    2013-07-01

    Full Text Available Within the context of long-lived intermediate level radioactive waste geological disposal, reinforced concrete would be used. In service life conditions, the concrete structures would be subjected to drying and carbonation. Carbonation relates to the reaction between carbon dioxide (CO2 and the main hydrates of the cement paste (portlandite and C-S-H. Beyond the fall of the pore solution pH, indicative of steel depassivation, carbonation induces mineralogical and microstructural changes (due to portlandite and C-S-H dissolution and calcium carbonate precipitation. This results in the modification of the transport properties, which can impact the structure durability. Because concrete durability depends on water transport, this study focuses on the influence of carbonation on water transport properties. In fact, the transport properties of sound materials are known but they still remain to be assessed for carbonated ones. An experimental program has been designed to investigate the transport properties in carbonated materials. Four hardened cement pastes, differing in mineralogy, are carbonated in an accelerated carbonation device (in controlled environmental conditions at CO2 partial pressure of about 3%. Once fully carbonated, all the data needed to describe water transport, using a simplified approach, will be evaluated.

  18. Investigations of the transport behavior of contaminants in fresh water/brine systems under consideration of density differences; Untersuchungen zum Transportverhalten von Schadstoffen in Suess- / Salzwassersystemen unter Beruecksichtigung von Dichteunterschieden

    Energy Technology Data Exchange (ETDEWEB)

    Larue, Juergen; Weyand, Torben; Mayer, Kim-Marisa

    2016-10-15

    This report contains a compilation of national and international experience gathered as part of a research project sponsored by the BMUB concerning the aspect of the transport behaviour of contaminants in freshwater/brine systems with consideration of density and viscosity differences. The fundamentals of modelling density-dependent flows are presented and a series of examples of the application with different codes and their uses with reference to real sites is described. Besides an overview of test cases for the verification of these codes, the further development of the instruments available to GRS and test calculations regarding their implementation are presented.

  19. Climate change intensification of horizontal water vapor transport in CMIP5

    Science.gov (United States)

    Lavers, David A.; Ralph, F. Martin; Waliser, Duane E.; Gershunov, Alexander; Dettinger, Michael D.

    2015-07-01

    Global warming of the Earth's atmosphere is hypothesized to lead to an intensification of the global water cycle. To determine associated hydrological changes, most previous research has used precipitation. This study, however, investigates projected changes to global atmospheric water vapor transport (integrated vapor transport (IVT)), the key link between water source and sink regions. Using 22 global circulation models from the Climate Model Intercomparison Project Phase 5, we evaluate, globally, the mean, standard deviation, and the 95th percentiles of IVT from the historical simulations (1979-2005) and two emissions scenarios (2073-2099). Considering the more extreme emissions, multimodel mean IVT increases by 30-40% in the North Pacific and North Atlantic storm tracks and in the equatorial Pacific Ocean trade winds. An acceleration of the high-latitude IVT is also shown. Analysis of low-altitude moisture and winds suggests that these changes are mainly due to higher atmospheric water vapor content.

  20. The evolution of water transport in plants: an integrated approach.

    Science.gov (United States)

    Pittermann, J

    2010-03-01

    This review examines the evolution of the plant vascular system from its beginnings in the green algae to modern arborescent plants, highlighting the recent advances in developmental, organismal, geochemical and climatological research that have contributed to our understanding of the evolution of xylem. Hydraulic trade-offs in vascular structure-function are discussed in the context of canopy support and drought and freeze-thaw stress resistance. This qualitative and quantitative neontological approach to palaeobotany may be useful for interpreting the water-transport efficiencies and hydraulic limits in fossil plants. Large variations in atmospheric carbon dioxide levels are recorded in leaf stomatal densities, and may have had profound impacts on the water conservation strategies of ancient plants. A hypothesis that links vascular function with stomatal density is presented and examined in the context of the evolution of wood and/or vessels. A discussion of the broader impacts of plant transport on hydrology and climate concludes this review.

  1. Superconductivity and fast proton transport in nanoconfined water

    Science.gov (United States)

    Johnson, K. H.

    2018-04-01

    A real-space molecular-orbital density-wave description of Cooper pairing in conjunction with the dynamic Jahn-Teller mechanism for high-Tc superconductivity predicts that electron-doped water confined to the nanoscale environment of a carbon nanotube or biological macromolecule should superconduct below and exhibit fast proton transport above the transition temperature, Tc ≅ 230 K (-43 °C).

  2. Co-regulation of water and K(+) transport in sunflower plants during water stress recovery.

    Science.gov (United States)

    Benlloch, Manuel; Benlloch-González, María

    2016-06-01

    16-day-old sunflower (Helianthus annuus L.) plants were subjected to deficit irrigation for 12 days. Following this period, plants were rehydrated for 2 days to study plant responses to post-stress recovery. The moderate water stress treatment applied reduced growth in all plant organs and the accumulation of K(+) in the shoot. After the rehydration period, the stem recovered its growth and reached a similar length to the control, an effect which was not observed in either root or leaves. Moreover, plant rehydration after water stress favored the accumulation of K(+) in the apical zone of the stem and expanding leaves. In the roots of plants under water stress, watering to field capacity, once the plants were de- topped, rapidly favored K(+) and water transport in the excised roots. This quick and short-lived response was not observed in roots of plants recovered from water stress for 2 days. These results suggest that the recovery of plant growth after water stress is related to coordinated water and K(+) transport from the root to the apical zone of the ​​stem and expanding leaves. This stimulation of K(+) transport in the root and its accumulation in the cells of the growing zones of the ​​stem must be one of the first responses induced in the plant during water stress recovery. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. Performance of a Cross-Flow Humidifier with a High Flux Water Vapor Transport Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R. K.; Wang, X.; Johnson, W. B.; Berg, F.; Kadylak, D.

    2015-09-30

    Water vapor transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flow humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower pressures, but the mass transfer effectiveness is higher at higher pressures. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the gradient in RH of the wet and dry streams but is also affected by vapor diffusion in the gas layer and the microporous layer.

  4. Mercuric Chloride Effects on Root Water Transport in Aspen Seedlings.

    Science.gov (United States)

    Wan; Zwiazek

    1999-11-01

    HgCl(2) (0.1 mM) reduced pressure-induced water flux and root hydraulic conductivity in the roots of 1-year-old aspen (Populus tremuloides Michx.) seedlings by about 50%. The inhibition was reversed with 50 mM mercaptoethanol. Mercurial treatment reduced the activation energy of water transport in the roots from 10.82 +/- 0.700 kcal mol(-1) to 6.67 +/- 0.193 kcal mol(-1) when measured over the 4 degrees C to 25 degrees C temperature range. An increase in rhodamine B concentration in the xylem sap of mercury-treated roots suggested a decrease in the symplastic transport of water. However, the apoplastic pathway in both control and mercury-treated roots constituted only a small fraction of the total root water transport. Electrical conductivity and osmotic potentials of the expressed xylem sap suggested that 0.1 mM HgCl(2) and temperature changes over the 4 degrees C to 25 degrees C range did not induce cell membrane leakage. The 0.1 mM HgCl(2) solution applied as a root drench severely reduced stomatal conductance in intact plants, and this reduction was partly reversed by 50 mM mercaptoethanol. In excised shoots, 0.1 mM HgCl(2) did not affect stomatal conductance, suggesting that the signal that triggered stomatal closure originated in the roots. We suggest that mercury-sensitive processes in aspen roots play a significant role in regulating plant water balance by their effects on root hydraulic conductivity.

  5. MX Siting Investigation Water Resources Program.

    Science.gov (United States)

    1980-10-31

    Henningson, Durham and Richardson (HDR) Sciences in Santa Barbara, Califor- nia, on 15 May 1980. The report was submitted to HDR Sciences at that time so...4400 acre-feet (5.4 hm3 ) for a primary base and 6380 acre-feet (7.9 hm3 ) for cluster construction, during the peak construction-water use year. What...This is evidenced by the combined i discharge of 13,600 gpm (858 1/s) which issues from Hiko (4S/60- 22), Crystal (5G,/60-10), and Ash (5S/60-36

  6. Organic nature of colloidal actinides transported in surface water environments.

    Science.gov (United States)

    Santschi, Peter H; Roberts, Kimberly A; Guo, Laodong

    2002-09-01

    Elevated levels of (239,240)Pu and 241Am have been present in surficial soils of the Rocky Flats Environmental Technology Site (RFETS), CO, since the 1960s, when soils were locally contaminated in the 1960s by leaking drums stored on the 903 Pad. Further dispersion of contaminated soil particles was by wind and water. From 1998 until 2001, we examined actinide ((239,240)Pu and 241Am) concentrations and phase speciation in the surface environment at RFETS through field studies and laboratory experiments. Measurements of total (239,240)Pu and 241Am concentrations in storm runoff and pond discharge samples, collected during spring and summer times in 1998-2000, demonstrate that most of the (239,240)Pu and 241Am transported from contaminated soils to streams occurred in the particulate (> or = 0.45 microm; 40-90%) and colloidal (approximately 2 nm or 3 kDa to 0.45 microm; 10-60%) phases. Controlled laboratory investigations of soil resuspension, which simulated storm and erosion events, confirmed that most of the Pu in the 0.45 microm filter-passing phase was in the colloidal phase (> or = 80%) and that remobilization of colloid-bound Pu during soil erosion events can be greatly enhanced by humic and fulvic acids present in these soils. Most importantly, isoelectric focusing experiments of radiolabeled colloidal matter extracted from RFETS soils revealed that colloidal Pu is in the four-valent state and is mostly associated with a negatively charged organic macromolecule with a pH(IEP) of 3.1 and a molecular weight of 10-15 kDa, rather than with the more abundant inorganic (iron oxide and clay) colloids. This finding has important ramifications for possible remediation, erosion controls, and land-management strategies.

  7. Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-26

    Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy. In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240

  8. Effect of passive transport of water through plasma membrane in production of extracellular enzyme.

    Science.gov (United States)

    Mahmoodi, M; Najafpour, G D; Mohammadi, M

    2017-02-01

    In this article, availability and control of water in solid-state fermentation (SSF) were investigated. Based on passive transport of water through plasma membranes, a new model was proposed for calculation and control of water activities in the mixture of solids. The validity of theoretical model and accuracy of the proposed model were proved by experimental data. This model was used for production of pectinases via mixed-SSF with the aid of a rotary drum bioreactor. It was found that in case of extracellular enzyme production, the new model is in good agreement with experimental data for the control of water activities in the mixed-SSF. Exact control of water activity in SFF, the production of endo- and exo-pectinases was relatively enhanced. Based on theoretical view point, the prominence of this new model in control of water activity was also proved.

  9. A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

    2000-01-01

    A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing...... increases with hydraulic conductance of the pathway carrying water from mucosal solution into lis. Uphill water transport is accomplished, but with high hydraulic conductance of cell membranes strength of transport is obscured by water flow through cells. Anomalous solvent drag occurs when back flux...

  10. Investigation of hydrate formation and transportability in multiphase flow systems

    Science.gov (United States)

    Grasso, Giovanny A.

    cohesion force (3.32 mN/m). These measurements prove the importance of natural surfactants in crude oil for particle dispersion. An experimental methodology was provided to determine the effectiveness of asphaltenes as a dispersant. Even though hydrate deposition was inferred from the flowloop tests, it could not be verified from these measurements. Custom-made experimental set-ups (a recirculation liquid system, a rocking cell and a lab-scale mini-loop) were used to isolate the hydrate deposi- tion investigation. Besides water, mineral oil 70T and King Ranch condensate were used in combination with water for the deposition investigation. One of the most important deliverables of this thesis was the construction of a lab-scale flowloop that provides insight on deposition phenomenon in multiphase flow, representing the only set-up, reported in the literature, suitable for this investigation. The miniloop can handle gas-liquid flow (maximum flow rates of 10 Nm3/m for gas and 22 GPM for liquid) through a 10 ft. long straight section (2 in. standard tubing). The testing section (30 in. long) was designed to observe hydrate deposition on the wall. Three mechanisms of hydrate deposition were identified: film growth, particles adhering and particle bedding. The maximum water conversions were: 27.5 ml in the rocking cell, 2400 ml in the miniloop with 100 % WC and 250 ml in the miniloop for dispersed water in mineral oil 70T. The measured DP across to the testing section ranged from 0 to 8 in. H2O. Deposits were obtained for different flow regimes, including 100 % LL, stratified, stratified- wavy and slug flow. The maximum deposit thickness was 1.5 in., obtained in the gas flowing section. When deposits form from particle cohesion, they were easy to slough. From all the experimental worked in this thesis, hydrates accumulated depending on the degrees of subcooling of the bulk fluid, film growth (between 3 to 5 F), deposition from a combination of film growth and particle cohesion

  11. Moisture harvesting and water transport through specialized micro-structures on the integument of lizards

    Directory of Open Access Journals (Sweden)

    Philipp Comanns

    2011-04-01

    Full Text Available Several lizard species that live in arid areas have developed special abilities to collect water with their bodies' surfaces and to ingest the so collected moisture. This is called rain- or moisture-harvesting. The water can originate from air humidity, fog, dew, rain or even from humid soil. The integument (i.e., the skin plus skin derivatives such as scales has developed features so that the water spreads and is soaked into a capillary system in between the reptiles' scales. Within this capillary system the water is transported to the mouth where it is ingested. We have investigated three different lizard species which have developed the ability for moisture harvesting independently, viz. the Australian thorny devil (Moloch horridus, the Arabian toadhead agama (Phrynocephalus arabicus and the Texas horned lizard (Phrynosoma cornutum. All three lizards have a honeycomb like micro ornamentation on the outer surface of the scales and a complex capillary system in between the scales. By investigation of individual scales and by producing and characterising polymer replicas of the reptiles' integuments, we found that the honeycomb like structures render the surface superhydrophilic, most likely by holding a water film physically stable. Furthermore, the condensation of air humidity is improved on this surface by about 100% in comparison to unstructured surfaces. This allows the animals to collect moisture with their entire body surface. The collected water is transported into the capillary system. For Phrynosoma cornutum we found the interesting effect that, in contrast to the other two investigated species, the water flow in the capillary system is not uniform but directed to the mouth. Taken together we found that the micro ornamentation yields a superhydrophilic surface, and the semi-tubular capillaries allow for an efficient passive – and for Phrynosoma directed – transport of water.

  12. Moisture harvesting and water transport through specialized micro-structures on the integument of lizards.

    Science.gov (United States)

    Comanns, Philipp; Effertz, Christian; Hischen, Florian; Staudt, Konrad; Böhme, Wolfgang; Baumgartner, Werner

    2011-01-01

    Several lizard species that live in arid areas have developed special abilities to collect water with their bodies' surfaces and to ingest the so collected moisture. This is called rain- or moisture-harvesting. The water can originate from air humidity, fog, dew, rain or even from humid soil. The integument (i.e., the skin plus skin derivatives such as scales) has developed features so that the water spreads and is soaked into a capillary system in between the reptiles' scales. Within this capillary system the water is transported to the mouth where it is ingested. We have investigated three different lizard species which have developed the ability for moisture harvesting independently, viz. the Australian thorny devil (Moloch horridus), the Arabian toadhead agama (Phrynocephalus arabicus) and the Texas horned lizard (Phrynosoma cornutum). All three lizards have a honeycomb like micro ornamentation on the outer surface of the scales and a complex capillary system in between the scales. By investigation of individual scales and by producing and characterising polymer replicas of the reptiles' integuments, we found that the honeycomb like structures render the surface superhydrophilic, most likely by holding a water film physically stable. Furthermore, the condensation of air humidity is improved on this surface by about 100% in comparison to unstructured surfaces. This allows the animals to collect moisture with their entire body surface. The collected water is transported into the capillary system. For Phrynosoma cornutum we found the interesting effect that, in contrast to the other two investigated species, the water flow in the capillary system is not uniform but directed to the mouth. Taken together we found that the micro ornamentation yields a superhydrophilic surface, and the semi-tubular capillaries allow for an efficient passive - and for Phrynosoma directed - transport of water.

  13. Characterizing the transplanar and in-plane water transport of textiles with gravimetric and image analysis technique: Spontaneous Uptake Water Transport Tester.

    Science.gov (United States)

    Tang, K P M; Wu, Y S; Chau, K H; Kan, C W; Fan, J T

    2015-04-15

    Water absorption and transport property of textiles is important since it affects wear comfort, efficiency of treatment and functionality of product. This paper introduces an accurate and reliable measurement tester, which is based on gravimetric and image analysis technique, for characterising the transplanar and in-plane wicking property of fabrics. The uniqueness of this instrument is that it is able to directly measure the water absorption amount in real-time, monitor the direction of water transport and estimate the amount of water left on skin when sweating. Throughout the experiment, water supply is continuous which simulates profuse sweating. Testing automation could even minimise variation caused by subjective manipulation, thus enhancing testing accuracy. This instrument is versatile in terms of the fabrics could be tested. A series of shirting fabrics made by different fabric structure and yarn were investigated and the results show that the proposed method has high sensitivity in differentiating fabrics with varying geometrical differences. Fabrics with known hydrophobicity were additionally tested to examine the sensitivity of the instrument. This instrument also demonstrates the flexibility to test on high performance moisture management fabrics and these fabrics were found to have excellent transplanar and in-plane wicking properties.

  14. Characterizing the transplanar and in-plane water transport of textiles with gravimetric and image analysis technique: Spontaneous Uptake Water Transport Tester

    Science.gov (United States)

    Tang, K. P. M.; Wu, Y. S.; Chau, K. H.; Kan, C. W.; Fan, J. T.

    2015-01-01

    Water absorption and transport property of textiles is important since it affects wear comfort, efficiency of treatment and functionality of product. This paper introduces an accurate and reliable measurement tester, which is based on gravimetric and image analysis technique, for characterising the transplanar and in-plane wicking property of fabrics. The uniqueness of this instrument is that it is able to directly measure the water absorption amount in real-time, monitor the direction of water transport and estimate the amount of water left on skin when sweating. Throughout the experiment, water supply is continuous which simulates profuse sweating. Testing automation could even minimise variation caused by subjective manipulation, thus enhancing testing accuracy. This instrument is versatile in terms of the fabrics could be tested. A series of shirting fabrics made by different fabric structure and yarn were investigated and the results show that the proposed method has high sensitivity in differentiating fabrics with varying geometrical differences. Fabrics with known hydrophobicity were additionally tested to examine the sensitivity of the instrument. This instrument also demonstrates the flexibility to test on high performance moisture management fabrics and these fabrics were found to have excellent transplanar and in-plane wicking properties. PMID:25875329

  15. The Structure and Transport of Water and Hydrated Ions Within Hydrophobic, Nanoscale Channels

    Energy Technology Data Exchange (ETDEWEB)

    Holt, J K; Herberg, J L; Wu, Y; Schwegler, E; Mehta, A

    2009-06-15

    The purpose of this project includes an experimental and modeling investigation into water and hydrated ion structure and transport at nanomaterials interfaces. This is a topic relevant to understanding the function of many biological systems such as aquaporins that efficiently shuttle water and ion channels that permit selective transport of specific ions across cell membranes. Carbon nanotubes (CNT) are model nanoscale, hydrophobic channels that can be functionalized, making them artificial analogs for these biological channels. This project investigates the microscopic properties of water such as water density distributions and dynamics within CNTs using Nuclear Magnetic Resonance (NMR) and the structure of hydrated ions at CNT interfaces via X-ray Absorption Spectroscopy (XAS). Another component of this work is molecular simulation, which can predict experimental measurables such as the proton relaxation times, chemical shifts, and can compute the electronic structure of CNTs. Some of the fundamental questions this work is addressing are: (1) what is the length scale below which nanoscale effects such as molecular ordering become important, (2) is there a relationship between molecular ordering and transport?, and (3) how do ions interact with CNT interfaces? These are questions of interest to the scientific community, but they also impact the future generation of sensors, filters, and other devices that operate on the nanometer length scale. To enable some of the proposed applications of CNTs as ion filtration media and electrolytic supercapacitors, a detailed knowledge of water and ion structure at CNT interfaces is critical.

  16. Dealing with water deficit in Atta ant colonies: large ants scout for water while small ants transport it

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Da-Silva

    2012-07-01

    Leafcutter ants (Atta sexdens rubropilosa (Forel 1908 have an elaborate social organization, complete with caste divisions. Activities carried out by specialist groups contribute to the overall success and survival of the colony when it is confronted with environmental challenges such as dehydration. Ants detect variations in humidity inside the nest and react by activating several types of behavior that enhance water uptake and decrease water loss, but it is not clear whether or not a single caste collects water regardless of the cost of bringing this resource back to the colony. Accordingly, we investigated water collection activities in three colonies of Atta sexdens rubropilosa experimentally exposed to water stress. Specifically, we analyzed whether or not the same ant caste foraged for water, regardless of the absolute energetic cost (distance of transporting this resource back to the colony. Our experimental design offered water sources at 0 m, 1 m and 10 m from the nest. We studied the body size of ants near the water sources from the initial offer of water (time  =  0 to 120 min, and tested for specialization. We observed a reduction in the average size and variance of ants that corroborated the specialization hypothesis. Although the temporal course of specialization changed with distance, the final outcome was similar among distances. Thus, we conclude that, for this species, a specialist (our use of the word “specialist” does not mean exclusive task force is responsible for collecting water, regardless of the cost of transporting water back to the colony.

  17. Vessel-Generated Ballast Water: Gray Water Investigation

    Science.gov (United States)

    2015-09-01

    is either heat treated, sandblasted to a specific surface profile , or coated with different materials, depending on the experiment being performed...multiple pools, restaurants , bathrooms and bars, all contribute to the quantity of gray water created. This wastewater coming from many different sources...Treatment Methods Ballast tanks are used by sea going vessels to increase stability. As vessels offload cargo or consume onboard stores, such as fuel and

  18. Investigation of potential water quality and quantity impacts ...

    African Journals Online (AJOL)

    A scoping level study was performed to consolidate the existing information on the geohydrology and pre-mining water quantity and quality of water resources associated with the Waterberg coal reserves. New data regarding water quality and acid-base potential for the different geological areas (through field investigations) ...

  19. European CO2 emission trends: A decomposition analysis for water and aviation transport sectors

    International Nuclear Information System (INIS)

    Andreoni, V.; Galmarini, S.

    2012-01-01

    A decomposition analysis is used to investigate the main factors influencing the CO 2 emissions of European transport activities for the period 2001–2008. The decomposition method developed by Sun has been used to investigate the carbon dioxide emissions intensity, the energy intensity, the structural changes and the economy activity growth effects for the water and the aviation transport sectors. The analysis is based on Eurostat data and results are presented for 14 Member States, Norway and EU27. Results indicate that economic growth has been the main factor behind the carbon dioxide emissions increase in EU27 both for water and aviation transport activities. -- Highlights: ► Decomposition analysis is used to investigate factors that influenced the energy-related CO 2 emissions of European transport. ► Economic growth has been the main factor affecting the energy-related CO 2 emissions increases. ► Investigating the CO 2 emissions drivers is the first step to define energy efficiency policies and emission reduction strategies.

  20. Hydrological model for the transport of radioisotope in surface water

    International Nuclear Information System (INIS)

    Adoboah, E.K.

    2011-01-01

    The use of radioisotopes has gained grounds in Ghana as a result of the numerous benefits that could be derived from it. In Ghana, radioisotope materials are used for various purposes in a number of institutions. However, improper disposal of the waste poses threat to the environment. To evaluate the environmental impact of radioisotope pollution, mathematical models play a major role in predicting the pollution level in any medium. This study is concerned with the hydrological model for the transport of radioactive material in the river. The model was composed by employing partial differential equations, describing relevant physical processes evolution (water level, velocities and dissolved substances concentrations) that occurs in water bodies. The mass conservation and momentum laws, state equation and state transport equations are equation system basis. The explicit central difference scheme in space and a forward difference method in time were used for the evaluation of the generalized transport equation, the Advection-Dispersion Equation. A Matlab code was developed to predict the concentration of the radioactive contaminant at any particular time along the river and in a reservoir. The model was able to simulate accurately the various levels of radionuclide concentration changes in the flowing rivers as the flows are augmented by tributary inflows. (au)

  1. Investigating anomalous transport of electrolytes in charged porous media

    Science.gov (United States)

    Skjøde Bolet, Asger Johannes; Mathiesen, Joachim

    2017-04-01

    Surface charge is know to play an important role in microfluidics devices when dealing with electrolytes and their transport properties. Similarly, surface charge could play a role for transport in porous rock with submicron pore sizes. Estimates of the streaming potentials and electro osmotic are mostly considered in simple geometries both using analytic and numerical tools, however it is unclear at present how realistic complex geometries will modify the dynamics. Our work have focused on doing numerical studies of the full three-dimensional Stokes-Poisson-Nernst-Planck problem for electrolyte transport in porous rock. As the numerical implementation, we have used a finite element solver made using the FEniCS project code base, which can both solve for a steady state configuration and the full transient. In the presentation, we will show our results on anomalous transport due to electro kinetic effects such as the streaming potential or the electro osmotic effect.

  2. Soil heterogeneity effects on water and solute transport. Methodological comparison in different climates

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Hiroshi

    1996-11-01

    Spatial heterogeneity of soils is important to consider for soil water and solute transport. The results of the present work indicated that spatial heterogeneity affects all investigated soils and for widely varying climates. Both soil water content and temperature patterns for a bare and vegetated transect in a typical sand dune area in China indicated preferential transport of soil water after rainfall. Infiltrating soil water appeared to follow paths that had high water content before the rainfall. The effect of rainfall was therefore not a larger uniformity of soil water, but rather increasing variability. Preferential flow was observed by tracer and dye in Tunisia. The experimental data indicated a high degree of bypass or preferential flow within small plots and non-sigmoid breakthrough curves suggesting tailing phenomena and immobile fractions of soil water. The groundwater tracer concentration increased up to twice the concentration of the water in the unsaturated zone withdrawn from different depths. This consequently shows that bypass directly to the groundwater occurred also for unsaturated conditions. Soil layering appeared to be a significant cause for preferential flow for both sand and clay soils. The results also showed great variability for hydraulic properties in terms of van Genuchten parameters for a small plot in a temperate climate. The present work supports the dual-porosity hypothesis. But findings also indicate that the observation scale is important to consider when averaging the process in time and space. 95 refs, 7 figs, 1 tab

  3. Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas

    Energy Technology Data Exchange (ETDEWEB)

    Dexin Wang

    2012-03-31

    The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

  4. Fate and Transport of Nutrients in Groundwater and Surface Water in an Urban Slum Catchment Kampala, Uganda

    NARCIS (Netherlands)

    Nyenje, P.

    2014-01-01

    This study investigates the generation, transport and fate of sanitation-related nutrients in groundwater and surface water in an urban slum area in sub-Saharan Africa. In excess, nutrients can cause eutrophication of downstream water bodies. The study argues that nitrogen-containing rains and

  5. Using SRμCT to define water transport capacity in Picea abies

    Science.gov (United States)

    Lautner, Silke; Lenz, Claudia; Hammel, Jörg; Moosmann, Julian; Kühn, Michael; Caselle, Michele; Vogelgesang, Matthias; Kopmann, Andreas; Beckmann, Felix

    2017-10-01

    Water transport from roots to shoots is a vital necessity in trees in order to sustain their photosynthetic activity and, hence, their physiological activity. The vascular tissue in charge is the woody body of root, stem and branches. In gymnosperm trees, like spruce trees (Picea abies (L.) Karst.), vascular tissue consists of tracheids: elongated, protoplast- free cells with a rigid cell wall that allow for axial water transport via their lumina. In order to analyze the over-all water transport capacity within one growth ring, time-consuming light microscopy analysis of the woody sample still is the conventional approach for calculating tracheid lumen area. In our investigations at the Imaging Beamline (IBL) operated by the Helmholtz-Zentrum Geesthacht (HZG) at PETRA III storage ring of the Deutsches Elektronen-Synchrotron DESY, Hamburg, we applied SRμCT on small wood samples of spruce trees in order to visualize and analyze size and formation of xylem elements and their respective lumina. The selected high-resolution phase-contrast technique makes full use of the novel 20 MPixel CMOS area detector developed within the cooperation of HZG and the Karlsruhe data by light microscopy analysis and, hence, prove, that μCT is a most appropriate method to gain valid information on xylem cell structure and tree water transport capacity.

  6. Ground-water transport model selection and evaluation guidelines

    International Nuclear Information System (INIS)

    Simmons, C.S.; Cole, C.R.

    1983-01-01

    Guidelines are being developed to assist potential users with selecting appropriate computer codes for ground-water contaminant transport modeling. The guidelines are meant to assist managers with selecting appropriate predictive models for evaluating either arid or humid low-level radioactive waste burial sites. Evaluation test cases in the form of analytical solutions to fundamental equations and experimental data sets have been identified and recommended to ensure adequate code selection, based on accurate simulation of relevant physical processes. The recommended evaluation procedures will consider certain technical issues related to the present limitations in transport modeling capabilities. A code-selection plan will depend on identifying problem objectives, determining the extent of collectible site-specific data, and developing a site-specific conceptual model for the involved hydrology. Code selection will be predicated on steps for developing an appropriate systems model. This paper will review the progress in developing those guidelines. 12 references

  7. Water magnetization and phosphorus transport parameters in the soil

    Directory of Open Access Journals (Sweden)

    Tarcila N. Generoso

    Full Text Available ABSTRACT There are scientific studies describing changes in properties of the water when subjected to the action of a magnetic field, which may favor the availability of some nutrients in the soil solution. Some nutrients, although they are essential to the process of crop development, can be sources of pollution for watercourses and soil. The aim of this study was to evaluate the effect of water magnetization on transport parameters of the phosphate ion in a Red Latosol (RL and in a Quartzarenic Neosol (QN. Saturated leaching columns were connected to bottles containing KH2PO4 solutions. In RL, there were significant differences in phosphorus (P transport parameters, related to the retardation factor (R and distribution coefficient (Kd. For the others, Peclet number (Pe, dispersive-diffusion coefficient (D and dispersivity (λ, there were no significant differences in the comparison between the treatments with magnetized and non-magnetized water. In QN, there were statistical differences in R and Kd. For the other parameters, Pe, D and λ, there were no statistical differences between treatments.

  8. Interstitial Fibrosis Restricts Osmotic Water Transport in Encapsulating Peritoneal Sclerosis

    Science.gov (United States)

    Morelle, Johann; Sow, Amadou; Hautem, Nicolas; Bouzin, Caroline; Crott, Ralph

    2015-01-01

    Encapsulating peritoneal sclerosis (EPS) is a rare but severe complication of peritoneal dialysis (PD) characterized by extensive fibrosis of the peritoneum. Changes in peritoneal water transport may precede EPS, but the mechanisms and potential predictive value of that transport defect are unknown. Among 234 patients with ESRD who initiated PD at our institution over a 20-year period, 7 subsequently developed EPS. We evaluated changes in peritoneal transport over time on PD in these 7 patients and in 28 matched controls using 3.86% glucose peritoneal equilibration tests. Compared with long-term PD controls, patients with EPS showed early loss of ultrafiltration capacity and sodium sieving before the onset of overt EPS. Multivariate analysis revealed that loss of sodium sieving was the most powerful predictor of EPS. Compared with long-term PD control and uremic peritoneum, EPS peritoneum showed thicker submesothelial fibrosis, with increased collagen density and a greater amount of thick collagen fibers. Reduced osmotic conductance strongly correlated with the degree of peritoneal fibrosis, but not with vasculopathy. Peritoneal fibrosis was paralleled by an excessive upregulation of vascular endothelial growth factor and endothelial nitric oxide synthase, but the expression of endothelial aquaporin-1 water channels was unaltered. Our findings suggest that an early and disproportionate reduction in osmotic conductance during the course of PD is an independent predictor of EPS. This functional change is linked to specific alterations of the collagen matrix in the peritoneal membrane of patients with EPS, thereby validating the serial three-pore membrane/fiber matrix and distributed models of peritoneal transport. PMID:25636412

  9. Simulation of water transport through a lipid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Marrink, S.J.; Berendsen, H.J.C. (Univ. of Groningen (Netherlands))

    1994-04-14

    To obtain insight in the process of water permeation through a lipid membrane we performed molecular dynamics simulations on a phospholipid (DPPC)/water system with atomic detail. Since the actual process of permeation is too slow to be studied directly, we deduced the permeation rate indirectly via computation of the free energy and diffusion rate profiles of a water molecule across the bilayer. We concluded that the permeation of water through a lipid membrane cannot be described adequately by a simple homogeneous solubility-diffusion model. Both the excess free energy and the diffusion rate strongly depend on the position in the membrane, as a result from the inhomogeneous nature of the membrane. The calculated excess free energy profile has a shallow slope and a maximum height of 26 kJ/mol. The diffusion rate is highest in the middle of the membrane where the lipid density is low. In the interfacial region almost all water molecules are bound by the lipid headgroups, and the diffusion turns out to be 1 order of magnitude smaller. The total transport process is essentially determined by the free energy barrier. 78 refs., 12 figs.

  10. CFD modelling of insulation debris transport phenomena in water flow

    Energy Technology Data Exchange (ETDEWEB)

    Krepper, Eeckhard; Cartland-Glover, Gregory; Grahn, Alexander [Forschungszentrum Rossendorf e.V., Dresden (Germany). Inst. fuer Sicherheitsforschung

    2009-11-15

    The investigation of insulation debris generation, transport and sedimentation becomes important with regard to reactor safety research for PWR and BWR, when considering the long-term behaviour of emergency core cooling systems during all types of loss of coolant accidents. A joint research project on such questions is being performed in cooperation between the University of Applied Sciences Zittau/Goerlitz and the Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation of particle transport phenomena in coolant flow and the development of CFD models for its description. While the experiments are performed at the University at Zittau/Goerlitz, the theoretical modelling efforts are concentrated at Forschungszentrum Dresden-Rossendorf. In the current paper the basic concepts for CFD modelling are described and feasibility studies are presented. (orig.)

  11. Investigations on ruthenium transport in highly oxidising conditions

    International Nuclear Information System (INIS)

    Auvinen, A.; Backman, U.; Jokiniemi, J.; Lipponen, M.; Zilliacus, R.; Kissane, M.; Nagy, I.; Kunstar, M.; Ver, N.

    2005-01-01

    This paper presents results from ruthenium release, transport and speciation experiments obtained in recent European studies. Experiments have shown that ruthenium may be released from the fuel already at a relatively moderate temperature, if the cladding is breached and if the flow contains oxygen. Furthermore, a significant fraction of released ruthenium is expected to be transported in the primary circuit in gaseous form. This work helps to resolve a severe accident safety issue related to fission product release in highly oxidising environment, which was indicated in the EURSAFE phenomena identification and ranking table (PIRT) [1]. Ultimately the goal of the ongoing projects is to improve modelling of ruthenium transport phenomena in severe accident codes such as ASTEC/Sophaeros. (author)

  12. Modeling of Ultrathin Catalyst Layers in Polymer Electrolyte Fuel Cells: Proton Transport and Water Management

    OpenAIRE

    Chan, Karen Ka Wing

    2013-01-01

    Ultrathin catalyst layers (UTCLs) are emerging as a promising alternative to conventional catalyst layers in polymer electrolyte fuel cells. In comparison, UTCLs have dramatically reduced Pt loading and thicknesses and are ionomer–free. We explore two open questions in the theory of UTCLs (1) the proton transport mechanism within the ionomer–free layer and (2) water management in membrane electrode assemblies (MEAs) with UTCLs. To investigate (1), we present a UTCL model, which assumes the pr...

  13. Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex.

    Science.gov (United States)

    Kawedia, Jitesh D; Nieman, Michelle L; Boivin, Gregory P; Melvin, James E; Kikuchi, Ken-Ichiro; Hand, Arthur R; Lorenz, John N; Menon, Anil G

    2007-02-27

    To investigate potential physiological interactions between the transcellular and paracellular pathways of water transport, we asked whether targeted deletion of Aquaporin 5 (AQP5), the major transcellular water transporter in salivary acinar cells, affected paracellular transport of 4-kDa FITC-labeled dextran (FITC-D), which is transported through the paracellular but not the transcellular route. After i.v. injection of FITC-D into either AQP5 wild-type or AQP5-/- mice and saliva collection for fixed time intervals, we show that the relative amount of FITC-D transported in the saliva of AQP5-/- mice is half that in matched AQP5+/+ mice, indicating a 2-fold decrease in permeability of the paracellular barrier in mice lacking AQP5. We also found a significant difference in the proportion of transcellular vs. paracellular transport between male and female mice. Freeze-fracture electron microscopy revealed an increase in the number of tight junction strands of both AQP5+/+ and AQP5-/- male mice after pilocarpine stimulation but no change in strand number in female mice. Average acinar cell volume was increased by approximately 1.4-fold in glands from AQP5-/- mice, suggesting an alteration in the volume-sensing machinery of the cell. Western blots revealed that expression of Claudin-7, Claudin-3, and Occludin, critical proteins that regulate the permeability of the tight junction barrier, were significantly decreased in AQP5-/- compared with AQP5+/+ salivary glands. These findings reveal the existence of a gender-influenced molecular mechanism involving AQP5 that allows transcellular and paracellular routes of water transport to act in conjunction.

  14. Molecular-dynamics of water transport through membranes - water from solvent to solute

    NARCIS (Netherlands)

    BERENDSEN, HJC; MARRINK, SJ

    1993-01-01

    An application of Molecular Dynamics computer simulation (MD) to the process of transport of water through a lipid bilayer membrane is described. The permeation process is far too slow to be modeled by straightforward MD. In stead the inverse of the permeability coefficient is expressed as an

  15. Water stress inhibits hydraulic conductance and leaf growth in rice seedlings but not the transport of water via mercury-sensitive water channels in the root

    Science.gov (United States)

    Lu; Neumann

    1999-05-01

    The mechanisms by which moderate water stress (adding polyethylene glycol 6000 to the root medium) induces a sustained inhibition of growth in emerging first leaves of intact rice (Oryza sativa) seedlings was investigated under growth-chamber conditions. Early (24 h) inhibition of leaf growth was not related to changes in root size or in osmotic potential gradients and cell wall-yielding characteristics in the leaf-expansion zone of stressed seedlings. However, reductions in root-to-leaf hydraulic conductance (L) were measured in two rice cultivars after 4 or 24 h at various levels of water stress, and these reductions correlated well with the inhibition of leaf growth. We assayed L by a psychrometric method and, in intact seedlings, by a novel osmotic-jump method. The addition of 0.5 mM HgCl2 to the root medium to inhibit water transport through Hg-sensitive water channels in the roots did not inhibit leaf growth in unstressed seedlings. However, both leaf growth and L were additionally reduced (by 49% and 43%, respectively) within minutes of adding HgCl2 to roots of water-stressed seedlings. Water stress therefore appeared to increase the transport of water via Hg-sensitive water channels. Other mechanisms were apparently involved in inhibiting overall L and leaf growth.

  16. Role of Oxygen Functionalities in Graphene Oxide Architectural Laminate Subnanometer Spacing and Water Transport.

    Science.gov (United States)

    Amadei, Carlo Alberto; Montessori, Andrea; Kadow, Julian P; Succi, Sauro; Vecitis, Chad D

    2017-04-18

    Active research in nanotechnology contemplates the use of nanomaterials for environmental engineering applications. However, a primary challenge is understanding the effects of nanomaterial properties on industrial device performance and translating unique nanoscale properties to the macroscale. One emerging example consists of graphene oxide (GO) membranes for separation processes. Thus, here we investigate how individual GO properties can impact GO membrane characteristics and water permeability. GO chemistry and morphology were controlled with easy-to-implement photoreduction and sonication techniques and were quantitatively correlated, offering a valuable tool for accelerating characterization. Chemical GO modification allows for fine control of GO oxidation state, allowing control of GO architectural laminate (GOAL) spacing and permeability. Water permeability was measured for eight GOALs characterized by different GOAL chemistry and morphology and indicates that GOAL nanochannel height dictates water transport. The experimental outputs were corroborated with mesoscale water transport simulations of relatively large domains (thousands of square nanometers) and indicate a no-slip Darcy-like behavior inside the GOAL nanochannels. The experimental and simulation evidence presented in this study helps create a clearer picture of water transport in GOAL and can be used to rationally design more effective and efficient GO membranes.

  17. Relative turbulent transport efficiency and flux-variance relationships of temperature and water vapor

    Science.gov (United States)

    Hsieh, C. I.

    2016-12-01

    This study investigated the relative transport efficiency and flux-variance relationships of temperature and water vapor, and examined the performance of using this method for predicting sensible heat (H) and water vapor (LE) fluxes with eddy-covariance measured flux data at three different ecosystems: grassland, paddy rice field, and forest.The H and LE estimations were found to be in good agreement with the measurements over the three fields. The prediction accuracy of LE could be improved by around 15% if the predictions were obtained by the flux-variance method in conjunction with measured sensible heat fluxes. Moreover, the paddy rice field was found to be a special case where water vapor follows flux-variance relation better than heat does. The flux budget equations of heat and water vapor were applied to explain this phenomenon. Our results also showed that heat and water vapor were transported with the same efficiency above the grassland and rice paddy. For the forest, heat was transported 20% more efficiently than evapotranspiration.

  18. Peristaltic transport of copper-water nanofluid saturating porous medium

    Science.gov (United States)

    Abbasi, F. M.; Hayat, T.; Ahmad, B.

    2015-03-01

    Prime goal of present study is to model the problem for peristaltic transport of copper-water nanofluid in an asymmetric channel. The fluid fills porous space. Analysis is carried out in the presence of mixed conviction, viscous dissipation and heat generation/absorption. Long wavelength and low Reynolds number approximations are utilized in problem formulation. Numerical computations are presented for the axial velocity, pressure gradient, streamlines, temperature and heat transfer rate at the boundary. Graphical analysis is carried out to examine the effects of sundry parameters on flow quantities of interest. Results revealed that the axial velocity of copper-water nanofluid decreases with an increase in the nanoparticle volume fraction. Copper nanoparticles prove effective coolant since they sufficiently reduce the fluid temperature and show increase in the heat transfer between the fluid and solid boundary. Moreover temperature of the fluid decreases by increasing the permeability of porous medium.

  19. Fundamental investigation of the transport properties of superacids in aqueous and non-aqueous media

    Science.gov (United States)

    Suarez, Sophia

    In the quest to develop more efficient energy providers one of the main focus of research has been on the improvement of ion transport. In lithium battery research this has led to the incorporation of various lithium salts, ceramics and plasticizers into the poly(ethylene)oxide (PEO) matrix, the polymer most used In Proton Conduction Membrane (PCM) fuel cell research this has led to the development of new membranes, which are designed with to replicate Nafion's ((c)DuPont) proton transport but also improve upon its deficiency of transporting intact fuel molecules and its dependence upon the presence of solvating water molecules. To better understand the process of ion transport, NMR was used to investigate dynamic properties such as D (self-diffusion coefficient) and T1 (spin-lattice relaxation time) of various proton and lithium ion-conducting systems. Ionic conductivity and viscosity measurements were also performed. The systems studied includes aqueous superacid solutions (trifluoromethanesulfonic (TFSA), para-toluenesulfonic (PTSA) and bis(trifluoromethanesulfonyl)imide (TFSI)); nano-porous (NP-) PCM's incorporating various ceramics and 3M fuel/2M H2SO4 solutions; and P(EO)20LiBETI (LiN(SO 2CF2CF3)2 composite incorporating SiO 2 ceramic nano particles. The objective of the study of the superacid solutions was to determine the effect of concentration on the transport. It was found that beyond the ionic conductivity maximum, fluctuations in both D and T1 supports the existence of local ordering in the ionic network, caused by the reduced solvent dielectric coefficient and increasing viscosity. Of the three superacids TFSA was the most conductive and most affected by reduced solvent concentration. For the P(EO)20LiBETI composite the aim was to determine the effect of the ceramic on the ion transport of the composite in a solvent free environment. Results show that the ceramic causes only modest increase in the lithium transport below 90°C. The objective in the

  20. Hydrological balance and water transport processes of partially sealed soils

    Science.gov (United States)

    Timm, Anne; Wessolek, Gerd

    2017-04-01

    With increased urbanisation, soil sealing and its drastic effects on hydrological processes have received a lot of attention. Based on safety concerns, there has been a clear focus on urban drainage and prevention of urban floods caused by storm water events. For this reason, any kind of sealing is often seen as impermeable runoff generator that prevents infiltration and evaporation. While many hydrological models, especially storm water models, have been developed, there are only a handful of empirical studies actually measuring the hydrological balance of (partially) sealed surfaces. These challenge the general assumption of negligible infiltration and evaporation and show that these processes take place even for severe sealing such as asphalt. Depending on the material, infiltration from partially sealed surfaces can be equal to that of vegetated ones. Therefore, more detailed knowledge is needed to improve our understanding and models. In Berlin, two partially sealed weighable lysimeters were equipped with multiple temperature and soil moisture sensors in order to study their hydrological balance, as well as water and heat transport processes within the soil profile. This combination of methods affirms previous observations and offers new insights into altered hydrological processes of partially sealed surfaces at a small temporal scale. It could be verified that not all precipitation is transformed into runoff. Even for a relatively high sealing degree of concrete slabs with narrow seams, evaporation and infiltration may exceed runoff. Due to the lack of plant roots, the hydrological balance is mostly governed by precipitation events and evaporation generally occurs directly after rainfall. However, both surfaces allow for upward water transport from the upper underlying soil layers, sometimes resulting in relatively low evaporation rates on days without precipitation. The individual response of the surfaces differs considerably, which illustrates how

  1. Vapor Transport Modeling of Continental Water Isotope Gradients

    Science.gov (United States)

    Ritch, A. J.; Caves, J. K.; Ibarra, D. E.; Winnick, M. J.; Chamberlain, C. P.

    2015-12-01

    Stable isotopes have been widely used to reconstruct past climatic conditions and topographic histories of mountain belts. However, many studies do not account for the influences of evapotranspiration and vapor recycling on downstream meteoric water isotopic compositions. Here we present a case study of the modern Sierra Nevada and Basin and Range to illustrate the value of using process-based models across larger spatial scales to reconstruct the conditions driving local- to regional-scale water isotopic compositions. We use a one-dimensional reactive vapor transport model, driven by the National Centers for Environmental Prediction (NCEP) high-resolution North American Regional Reanalysis (NARR) dataset, to simulate the isotopic composition of modern meteoric waters (δ18O and δD) along storm tracks across the Sierra Nevada and Basin and Range. Storm track pathways are generated using NOAA's Air Resources Laboratory's Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. In addition, we couple the vapor transport model with a soil moisture model to simulate depth profiles of the oxygen isotopic composition of authigenic carbonate along our storm tracks. We show that, given reasonable estimates of the modern partitioning between evaporation and transpiration, our model output is in agreement with modern isotopic data both from compilations of published meteoric water samples and from newly collected soil carbonate samples along a transect across the northern Sierra Nevada and Basin and Range (~38-42° N). These results demonstrate that our modeling approach can be used to analyze the relative contributions of climate and topography to observed isotopic gradients. Future studies can apply this modeling framework to isotopes preserved in the geologic record to provide a quantitative means of understanding the paleoclimatic influences on spatial isotopic distributions.

  2. Effects of Cholesterol on the Thermodynamics and Kinetics of Passive Transport of Water through Lipid Membranes.

    Science.gov (United States)

    Issack, Bilkiss B; Peslherbe, Gilles H

    2015-07-23

    While it has long been known that cholesterol reduces the permeability of biological membranes to water, the exact mechanism by which cholesterol influences transmembrane permeation is still unclear. The thermodynamic and kinetic contributions to the transport of water across mixed DPPC/cholesterol bilayers of different composition are thus examined by molecular dynamics simulations. Our analyses show that cholesterol decreases transmembrane permeability to water mainly by altering the thermodynamics of water transport. In particular, the free-energy barrier to permeation is magnified in the dense bilayer interior and the partitioning of water is significantly lowered. The changes are observed to correlate quantitatively well with the cholesterol-dependent density and thickness of the bilayers. In contrast, diffusion coefficients are relatively insensitive to cholesterol concentration, except in the sparsely populated center of the bilayer. Diffusion of water in cholesterol-containing bilayers appears to be related to changes in the free area in the middle of the bilayer and to the solute cross-sectional area in the denser hydrophobic regions. Overall, cholesterol is found to have an inhibitory effect on the permeation of water at all concentrations investigated, although bilayers containing cholesterol concentrations up to 20 mol % display a more dramatic dependence on cholesterol content than at higher concentrations. Our results show that it is possible to quantitatively reproduce the relative effects of cholesterol on lipid bilayer permeability from molecular dynamics simulations.

  3. Investigation of mass transport properties of microfibrillated cellulose (MFC) films

    DEFF Research Database (Denmark)

    Minelli, Matteo; Baschetti, Marco Giacinti; Doghieri, Ferruccio

    2010-01-01

    , confirming the existence of complex structures below the film surface. In contrast, the diffusion coefficient was definitely affected by plasticization, being higher for glycerol-containing samples and showing in all cases an exponential increase when water was added to the system. Similar behavior...... the existence of complex structures in the different samples. A porous, closely packed fiber network, more homogeneous in the samples containing glycerol, was characteristic of the surface of MFC films; while film cross-sections presented a dense layered structure with no evidence of porosity. Water vapor...... sorption experiments confirmed the hydrophilic character of these cellulosic materials and showed a dual effect of glycerol which reduced the water uptake at low water activity while enhancing it at high relative humidity. The water diffusion in dry samples was remarkably slow for a porous material...

  4. Electrical transport and EPR investigations: A comparative study for ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 35; Issue 5. Electrical transport and EPR ... The charge carriers show a change over from 3D VRH to quasi 1D VRH hopping process for multivalent ions at higher doping levels whereas 1D VRH has been followed by monovalent ion for full doping range. These studies ...

  5. Dual-permeability model for water flow and solute transport in shrinking soils

    Science.gov (United States)

    Coppola, Antonio; Gerke, Horst; Comegna, Alessandro; Basile, Angelo

    2014-05-01

    A dual-permeability approach was extended to describe preferential water flow and solute transport in shrinking soils. In the approach, the soil is treated as a dual-permeability bulk porous medium consisting of dynamic interacting matrix and fractures pore domains. Water flow and solute transport in both the domains are described by the Richards' equation and advection-dispersion equation, respectively. In the model the contributions of the two regions to water flow and solute transport is changed dynamically according to the shrinkage characteristic exhibited under soil drying. Aggregate deformation during wetting/drying cycles is assumed to change only the relative proportions of voids in the fractures and in the aggregates, while the total volume of pores (and thus the layer thickness) remains unchanged. Thus, the partial contributions of the fracture and aggregate domains, are now a function of the water content (or the pressure head h), while their sum, the bulk porosity, is assumed to be constant. Any change in the aggregate contribution to total porosity is directly converted into a proportional change in the fracture porosity. This means that bulk volume change during shrinkage is mainly determined by change in crack volume rather than by change in layer thickness. This simplified approach allows dealing with an expansive soil as with a macroscopically rigid soil. The model was already tested by investigating whether and how well hydraulic characteristics obtained under the assumption of "dynamic" dual-permeability hydraulic parameterizations, or, alternatively, assuming the rigidity of the porous medium, reproduced measured soil water contents in a shrinking soil. Here we will discuss theoretical implications of the model in terms of relative importance of the parameters involved. The relative importance will be evaluated for different flow and transport processes and for different initial and top boundary conditions. Key words: Preferential flow and

  6. Modeling water flow and solute transport in unsaturated zone inside NSRAWD project

    International Nuclear Information System (INIS)

    Constantin, A.; Diaconu, D.; Bucur, C.; Genty, A.

    2015-01-01

    The NSRAWD project (2010-2013) - Numerical Simulations for Radioactive Waste Disposal was initiated under a collaboration agreement between the Institute for Nuclear Research and the French Alternative Energies and Atomic Energy Commission (CEA). The context of the project was favorable to combine the modeling activities with an experimental part in order to improve and validate the numerical models used so far to simulate water flow and solute transport at Saligny site, Romania. The numerical models developed in the project were refined and validated on new hydrological data gathered between 2010-2012 by a monitoring station existent on site which performs automatic determination of soil water content and matrix potential, as well as several climate parameters (wind, temperature and precipitations). Water flow and solute transport was modeled in transient conditions, by taking into consideration, as well as neglecting the evapotranspiration phenomenon, on the basis of a tracer test launched on site. The determination of dispersivities for solute transport was targeted from the solute plume. The paper presents the main results achieved in the NSRAWD project related to water flow and solute transport in the unsaturated area of the Saligny site. The results indicated satisfactory predictions for the simulation of water flow in the unsaturated area, in steady state and transient conditions. In the case of tracer transport modeling, dispersivity coefficients could not be finally well fitted for the data measured on site and in order to obtain a realistic preview over the values of these parameters, further investigations are recommended. The article is followed by the slides of the presentation

  7. Structure and Water Transport in Nafion Nanocomposite Membranes

    Science.gov (United States)

    Davis, Eric; Page, Kirt

    2014-03-01

    Perfluorinated ionomers, specifically Nafion, are the most widely used ion exchange membranes for vanadium redox flow battery applications, where an understanding of the relationship between membrane structure and transport of water/ions is critical to battery performance. In this study, the structure of Nafion/SiO2 nanocomposite membranes, synthesized using sol-gel chemistry, as well as cast directly from Nafion/SiO2 nanoparticle dispersions, was measured using both small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS). Through contrast match studies of the SiO2 nanoparticles, direct information on the change in the structure of the Nafion membranes and the ion-transport channels within was obtained, where differences in membrane structure was observed between the solution-cast membranes and the membranes synthesized using sol-gel chemistry. Additionally, water sorption and diffusion in these Nafion/SiO2 nanocomposite membranes were measured using in situ time-resolved Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy and dynamic vapor sorption (DVS).

  8. Aeromonas hydrophila disturbs water and electrolyte transport in ...

    African Journals Online (AJOL)

    Fish diseases create a menace to aquaculture farms. They provoke disastrous economic losses and sanitary risks for the consumer. The present study aims to investigate the effect of the bacteria, Aeromonas hydrophila on water and electrolyte (Na+, K+, Cl-, HCO3 -) flux of Mugil cephalus (L, 1758) intestine. Anterior, middle ...

  9. INVESTIGATION OF ATMOSPHERIC HUMIDITY TRANSPORT ON THE BASIS OF AEROLOGICAL MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    NYITRAI L.

    2015-03-01

    Full Text Available The global upper-air data base over the last 40 years is available by courtesy of College of Engineering and Applied Sciences at the University of Wyoming. Considering the fact, that in the atmospheric moisture transport between the oceans and the continents the humidity flow is much stronger towards the mainland than in the reverse direction, therefore it is reasonable to look for some correlation between the moisture transport and precipitation climate of the continents. For Europe, this is not easy because of the highly indented coastlines. According to laws of physics moisture transport influx to a (part of a continent i.e. through the border of a closed curve occurs as rain falling out in the water balance of the geographical area investigated. We are interested in quasi-stationary temporal changes showed by the stationary approach mentioned above that can be related to climate change. In Europe the precipitation regime of the rainy coast in Western Balkans can be described as a stationary approach, while the relationship between the moisture coming from the seas and the precipitation climate of Central and Eastern Europe in the past 40 years can be examined as a quasi-stationary process. This change in our region moves towards more frequent droughts having great economic influences, mainly in agriculture and hydrology. The aim of this study is to analyse the relationship between moisture convergence calculated by the radiosonde measurements and the precipitation climate of a selected area of land.

  10. Water flow and solute transport through fractured rock

    International Nuclear Information System (INIS)

    Bolt, J.E.; Bourke, P.J.; Pascoe, D.M.; Watkins, V.M.B.; Kingdon, R.D.

    1990-09-01

    In densely fractured slate at the Nirex research site in Cornwall, the positions, orientations and hydraulic conductivities of the 380 fractures intersecting a drill hole between 9 and 50 m depth have been individually measured. These data have been used: to determine the dimensions of statistically representative volumes of the network of fractures and to predict, using discrete flow path modelling and the NAPSAC code, the total flows into the fractures when large numbers are simultaneously pressurised along various lengths of the hole. Corresponding measurements, which validated the NAPSAC code to factor of two accuracy for the Cornish site, are reported. Possibilities accounting for this factor are noted for experimental investigation, and continuing, more extensive, inter hole flow and transport measurements are outlined. The application of this experimental and theoretical approach for calculating radionuclide transport in less densely fractured rock suitable for waste disposal is discussed. (Author)

  11. Investigations of Atomic Transport Induced by Heavy Ion Irradiation

    Science.gov (United States)

    Banwell, Thomas Clyde

    The mechanisms of atomic transport induced by ion irradiation generally fall into the categories of anisotropic or isotropic processes. Typical examples of these are recoil implantation and cascade mixing, respectively. We have measured the interaction of these processes in the mixing of Ti/SiO(,2)/Si, Cr/SiO(,2)/Si and Ni/SiO(,2)/Si multi-layers irradiated with Xe at fluences of 0.01 - 10 x 10('15)cm('-2). The fluence dependence of net metal transport into the underlying layers was measured with different thicknesses of SiO(,2) and different sample temperatures during irradiation (-196 to 500C). There is a linear dependence at low fluences. At high fluences, a square-root behavior predominates. For thin SiO(,2) layers (primary recoils is quite pronounced since the gross mixing is small. A significant correlation exists between the mixing and the energy deposited through elastic collisions F(,D ). Several models are examined in an attempt to describe the transport process in Ni/SiO(,2). It is likely that injection of Ni by secondary recoil implantation is primarily responsible for getting Ni into the SiO(,2). Secondary recoil injection is thought to scale with F(,D). Trends in the mixing rates indicate that the dominant mechanism for Ti and Cr could be the same as for Ni. The processes of atomic transport and phase formation clearly fail to be separable at higher temperatures. A positive correlation with chemical reactivity emerges at higher irradiation temperatures. The temperature at which rapid mixing occurs is not much below that for spontaneous thermal reaction. Less Ni is retained in the SiO(,2) at high irradiation temperatures. Ni incorporated in the SiO(,2) by low temperature irradiation is not expelled during a consecutive high temperature irradiation. The Ni remains trapped within larger clusters during a sequential 500C irradiation. (Abstract shortened with permission of author.).

  12. CFD-modeling of insulation debris transport phenomena in water flow

    Energy Technology Data Exchange (ETDEWEB)

    Krepper, Eckhard, E-mail: E.Krepper@fzd.d [Forschungszentrum Dresden-Rossendorf, Institute of Safety Research, Bautzner Landstrasse 128, 01328 Dresden (Germany); Cartland-Glover, Gregory; Grahn, Alexander; Weiss, Frank-Peter [Forschungszentrum Dresden-Rossendorf, Institute of Safety Research, Bautzner Landstrasse 128, 01328 Dresden (Germany); Alt, Soeren; Hampel, Rainer; Kaestner, Wolfgang; Seeliger, Andre [University of Applied Sciences Zittau/Goerlitz (FH), Theodor-Koerner-Allee 16, 02763 Zittau (Germany)

    2010-09-15

    The investigation of insulation debris generation, transport and sedimentation becomes important with regard to reactor safety research for PWR and BWR, when considering the long-term behavior of emergency core cooling systems during all types of loss of coolant accidents (LOCA). The insulation debris released near the break during a LOCA incident consists of a mixture of disparate particle population that varies with size, shape, consistency and other properties. Some fractions of the released insulation debris can be transported into the reactor sump, where it may perturb/impinge on the emergency core cooling systems. Open questions of generic interest are the sedimentation of the insulation debris in a water pool, its possible re-suspension and transport in the sump water flow and the particle load on strainers and corresponding pressure drop. A joint research project on such questions is being performed in cooperation between the University of Applied Sciences Zittau/Goerlitz and the Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation of particle transport phenomena in coolant flow and the development of CFD models for its description. While the experiments are performed at the University at Zittau/Goerlitz, the theoretical modeling efforts are concentrated at Forschungszentrum Dresden-Rossendorf. In the current paper the basic concepts for CFD-modeling are described and feasibility studies including the conceptual design of the experiments are presented.

  13. Particle transport in subaqueous eruptions: An experimental investigation

    Science.gov (United States)

    Verolino, A.; White, J. D. L.; Zimanowski, B.

    2018-01-01

    Subaqueous volcanic eruptions are natural events common under the world's oceans. Here we report results from bench-scale underwater explosions that entrain and eject particles into a water tank. Our aim was to examine how particles are transferred to the water column and begin to sediment from it, and to visualize and interpret evolution of the 'eruption' cloud. Understanding particle transfer to water is a key requirement for using deposit characteristics to infer behaviour and evolution of an underwater eruption. For the experiments here, we used compressed argon to force different types of particles, under known driving pressures, into water within a container, and recorded the results at 1 MPx/frame and 1000 fps. Three types of runs were completed: (1) particles within water were driven into a water-filled container; (2) dry particles were driven into water; (3) dry particles were driven into air at atmospheric pressure. Across the range of particles used for all subaqueous runs, we observed: a) initial doming, b) a main expansion of decompressing gas, and c) a phase of necking, when a forced plume separated from the driving jet. Phase c did not take place for the subaerial runs. A key observation is that none of the subaqueous explosions produced a single, simple, open cavity; in all cases, multiphase mixtures of gas bubbles, particles and water were formed. Explosions in which the expanding argon ejects particles in air, analogous to delivery of particles created in an explosion, produce jets and forced plumes that release particles into the tank more readily than do those in which particles in water are driven into the tank. The latter runs mimic propulsion of an existing vent slurry by an explosion. Explosions with different particle types also yielded differences in behaviour controlled primarily by particle mass, particle density, and particle-population homogeneity. Particles were quickly delivered into the water column during plume rise following

  14. Investigation of average daily water consumption and its impact on ...

    African Journals Online (AJOL)

    Investigation of average daily water consumption and its impact on weight gain in captive common buzzards ( Buteo buteo ) in Greece. ... At the end of 24 hours, the left over water was carefully brought out and re-measured to determine the quantity the birds have consumed. A control was set with a ceramic bowl with same ...

  15. An investigation into the prevalence of water borne diseases in ...

    African Journals Online (AJOL)

    Water-borne diseases are the most prevalent infectious diseases in the developing countries especially in new settlements along the river. The present investigation was carried out to assess the prevalence rate of water-borne diseases among people residing near the left bank of River Ravi. This study has a descriptive ...

  16. Water and chloride transport in a fine-textured soil in a feedlot pen

    Science.gov (United States)

    Veizaga, E. A.; Rodríguez, L.; Ocampo, C. J.

    2015-11-01

    Cattle feeding in feedlot pens produces large amounts of manure and animal urine. Manure solutions resulting from surface runoff are composed of numerous chemical constituents whose leaching causes salinization of the soil profile. There is a relatively large number of studies on preferential flow characterization and modeling in clayed soils. However, research on water flow and solute transport derived from cattle feeding operations in fine-textured soils under naturally occurring precipitation events is less frequent. A field monitoring and modeling investigation was conducted at two plots on a fine-textured soil near a feedlot pen in Argentina to assess the potential of solute leaching into the soil profile. Soil pressure head and chloride concentration of the soil solution were used in combination with HYDRUS-1D numerical model to simulate water flow and chloride transport resorting to the concept of mobile/immobile-MIM water for solute transport. Pressure head sensors located at different depths registered a rapid response to precipitation suggesting the occurrence of preferential flow-paths for infiltrating water. Cracks and small fissures were documented at the field site where the % silt and % clay combined is around 94%. Chloride content increased with depth for various soil pressure head conditions, although a dilution process was observed as precipitation increased. The MIM approach improved numerical results at one of the tested sites where the development of cracks and macropores is likely, obtaining a more dynamic response in comparison with the advection-dispersion equation.

  17. Experimental investigation of stepped solar still with continuous water circulation

    International Nuclear Information System (INIS)

    El-Agouz, S.A.

    2014-01-01

    Highlights: • Comparison between modified stepped and conventional solar still was carried out. • Effect of storage tank and cotton absorber on productivity was investigated. • Efficiency for modified stepped still is higher than conventional still by 20%. • The day and night efficiency increases by 5% and 3.5% for salt and sea water. - Abstract: This paper presents a modification of stepped solar still with continuous water circulation using a storage tank for sea and salt water. Total dissolved solids (TDS) of seawater and salt water before desalination is 57,100 and 2370 mg/l. A comparison study between modified stepped and conventional solar still was carried out to evaluate the developed desalination system performance under the same climate conditions. The effect of installing a storage tank and cotton black absorber for modified stepped solar still on the distillate productivity was investigated. The results indicate that, the productivity of the modified stepped still is higher than that for conventional still approximately by 43% and 48% for sea and salt water with black absorber respectively, while 53% and 47% of sea and salt water, respectively with cotton absorber. Also, the daily efficiency for modified stepped still is higher than that for conventional still approximately by 20%. The maximum efficiency of modified stepped still is occurring at a feed water flow rate of 1 LPM for sea water and 3 LPM for salt water. Total dissolved solids (TDS) of seawater and salt water after desalination is 41, and 27 mg/l

  18. Potential risk of microplastics transportation into ground water

    Science.gov (United States)

    Huerta, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A.; Geissen, Violette

    2016-04-01

    Microplastics, are plastics particles with a size smaller than 5mm. They are formed by the fragmentation of plastic wastes. They are present in the air, soil and water. But only in aquatic systems (ocean and rivers) are studies over their distribution, and the effect of microplastics on organisms. There is a lack of information of what is the distribution of microplastics in the soil, and in the ground water. This study tries to estimate the potential risk of microplastics transportation into the ground water by the activity of earthworms. Earthworms can produce burrows and/or galleries inside the soil, with the presence of earthworms some ecosystem services are enhanced, as infiltration. In this study we observed after 14 days with 5 treatments (0, 7, 28 and 60% w/w microplastics mixed with Populus nigra litter) and the anecic earthworm Lumbricus terrestris, in microcosms (3 replicas per treatment) that macroplastics are indeed deposit inside earthworms burrows, with 7% microplastics on the surface is possible to find 1.8 g.kg-1 microplastics inside the burrows, with a bioaumentation factor of 0.65. Burrows made by earthworms under 60% microplastics, are significant bigger (pmicroplastics in their soil surface. The amount of litter that is deposit inside the burrows is significant higher (pmicroplastics on the surface than without microplastics. The microplastics size distribution is smaller inside the burrows than on the surface, with an abundance of particles under 63 μm.

  19. "Sticky"-Ends-Guided Creation of Functional Hollow Nanopores for Guest Encapsulation and Water Transport.

    Science.gov (United States)

    Huo, Yanping; Zeng, Huaqiang

    2016-05-17

    Commercial uses of water-transporting aquaporins for seawater desalination and wastewater reclamation/reuse are being investigated in both academia and the industry. Presently, structural complexity, stability, scalability, and activity reconstitution of these costly channel proteins still present substantial challenges to scientists and engineers. An attractive strategy is to develop robust synthetic water channels able to mimic the water-transporting function of aquaporins for utility in the making of next generation of water channel-based biomimetic porous membranes for various water purification applications. In sharp contrast to burgeoning development in constructing synthetic ion channels over the past four decades, very limited progress has been made in the area of synthetic water channels. A handful of such examples include the first report by Percec in 2007 (Percec et al. J. Am. Chem. Soc. 2007, 129, 11698-11699), which was followed by Barboiu in 2011 (Barboiu et al. Angew. Chem., Int. Ed. 2011, 50, 11366-11372), Gong and Hou in 2012 (Gong et al. Nat. Commun. 2012, 3, 949; Hou et al. J. Am. Chem. Soc. 2012, 134, 8384-8387), and Zeng in 2014 (Zeng et al. J. Am. Chem. Soc. 2014, 136, 14270-14276). Radically deviating from the fact that the discovery of novel synthetic channel systems with desired transport selectivity is most often empirical and very often serendipitous, we have instead adopted a more rational designer approach whereby molecular building blocks have been carefully designed from scratch to perform their intended built-in functions. Our designer journey started in 2008, two years after I started leading a group at the National University of Singapore. Since then, we have been actively investigating the use of designed water-binding "aquafoldamers" to construct synthetic water channels for the rapid and selective transport of water molecules ideally with the exclusion of all other nonproton molecular species. Toward this goal, we designed and

  20. Measurements of water uptake of maize roots: insights for traits that influence water transport from the soil

    Science.gov (United States)

    Ahmed, Mutez A.; Zarebanadkouki, Mohsen; Kroener, Eva; Carminati, Andrea

    2015-04-01

    Water availability is a primary constraint to the global crop production. Although maize (Zea mays L.) is one of the most important crops worldwide, there is limited information on the function of different root segments and types in extracting water from soils. Aim of this study was to investigate the location of water uptake in maize roots. We used neutron radiography to: 1) image the spatial distribution of maize roots in soil and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants were grown in aluminum containers (40×38×1 cm) filled with sandy soil. The soil was partitioned into different compartments using 1-cm-thick layers of coarse sand. When the plants were two weeks-old we injected D2O into selected soil compartments. The experiments were performed during the day (transpiring plants) and night (non transpiring plants). The transport of D2O into roots was simulated using a convection-diffusion numerical model of D2O transport into roots. By fitting the observed D2O transport we quantified the diffusion coefficient and the water uptake of the different root segments. The maize root architecture consisted of a primary root, 4-5 seminal roots and many lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal 15 cm of the primary and seminal roots. Both during day and night measurements, D2O entered more quickly into lateral roots than into primary and seminal roots. The quick transport of D2O into laterals was caused by the small radius of lateral roots. The diffusion coefficient of lateral roots (4.68×10-7cm2s-1)was similar to that of the distal segments of seminal roots (4.72×10-7cm2s-1) and higher than of the proximal segments (1.42×10-7cm2s-1). Water uptake of lateral roots (1.64×10-5cms-1)was much higher than that of the distal segments of seminal roots (1.18×10-12cms-1). Water uptake of the proximal seminal segments was negligible. We conclude that the function of lateral

  1. The Effect of Cirrus Clouds on Water Vapor Transport in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Lei, L.; McCormick, M. P.; Anderson, J.

    2017-12-01

    Water vapor plays an important role in the Earth's radiation budget and stratospheric chemistry. It is widely accepted that a large percentage of water vapor entering the stratosphere travels through the tropical tropopause and is dehydrated by the cold tropopause temperature. The vertical transport of water vapor is also affected by the radiative effects of cirrus clouds in the tropical tropopause layer. This latter effect of cirrus clouds was investigated in this research. The work focuses on the tropical and mid-latitude region (50N-50S). Water vapor data from the Microwave Limb Sounder (MLS) and cirrus cloud data from the Cloud-Aerosol Lidar and Infrared pathfinder Satellite Observation (CALIPSO) instruments were used to investigate the relationship between the water vapor and the occurrence of cirrus cloud. A 10-degree in longitude by 10-degree in latitude resolution was chosen to bin the MLS and CALIPSO data. The result shows that the maximum water vapor in the upper troposphere (below 146 hPa) is matched very well with the highest frequency of cirrus cloud occurrences. Maximum water vapor in the lower stratosphere (100 hPa) is partly matched with the maximum cirrus cloud occurrence in the summer time. The National Oceanic and Atmospheric Administration Interpolated Outgoing Longwave Radiation data and NCEP-DOE Reanalysis 2 wind data were used also to investigate the relationship between the water vapor entering the stratosphere, deep convection, and wind. Results show that maximum water vapor at 100 hPa coincides with the northern hemisphere summer-time anticyclone. The effects from both single-layer cirrus clouds and cirrus clouds above the anvil top on the water vapor entering the stratosphere were also studied and will be presented.

  2. Influence of transport conditions and pre-slaughter water shower spray during summer on protein characteristics and water distribution of broiler breast meat.

    Science.gov (United States)

    Xing, Tong; Li, Yun Han; Li, Ming; Jiang, Nan Nan; Xu, Xing Lian; Zhou, Guang Hong

    2016-11-01

    This study investigated the effects of pre-slaughter transport during summer and subsequent water shower spray on broiler meat quality and protein characteristics. Arbor Acres broiler chickens (n = 126, 42 days old, mixed sex, 2.5-3 kg) were randomly categorized into three treatments: (i) control group without transport (C); (ii) 30 min transport (T); and (iii) 30 min transport followed by 10 min water shower spray and 20 min lairage (T/W). Each treatment consisted of six replicates with seven birds each. Ambient temperature was 32-35°C during transportation. Results indicated that transport during high ambient temperature denatured myosin and sarcoplasmic proteins, led to decreased protein solubility and resulted in glycogen phosphorylase precipitated to the myofibrillar fraction. Furthermore, meat quality in the transport group showed a pale, soft and exudative (PSE)-like syndrome. Water shower spray during lairage after transport reduced the degree of protein denaturation and lessened the deterioration of meat quality. © 2016 Japanese Society of Animal Science.

  3. Measurements and simulations of water transport in maize plants

    Science.gov (United States)

    Heinlein, Florian; Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2017-04-01

    In Central Europe climate change will become manifest in the increase of extreme weather events like flash floods, heat waves and summer droughts, and in a shift of precipitation towards winter months. Therefore, regional water availability will alter which has an effect on future crop growth, water use efficiency and yields. To better estimate these effects accurate model descriptions of transpiration and other parts of the water balance are important. In this study, we determined transpiration of four maize plants on a field of the research station Scheyern (about 40km North of Munich) by means of sap flow measurement devices (ICQ International Pty Ltd, Australia) using the Heat-Ratio-Method: two temperature probes, 0.5 cm above and below a heater, detect a heat pulse and its speed which facilitates the calculation of sap flow. Additionally, high resolution changes of stem diameters were measured with dendrometers (DD-S, Ecomatik). The field was also situated next to an eddy covariance station which provided latent heat fluxes from the soil-plant system. We also performed terrestrial laser scans of the respective plants to extract the plant architectures. These structures serve as input for our mechanistic transpiration model simulating the water transport within the plant. This model, which has already been successfully applied to single Fagus sylvatica L. trees, was adapted to agricultural plants such as maize. The basic principle of this model is to solve a 1-D Richards equation along the graph of the single plants. A comparison between the simulations and the measurements is presented and discussed.

  4. Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

    Science.gov (United States)

    F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

    2006-01-01

    The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

  5. An Investigation of Potable Water Supply Problems in Akinima ...

    African Journals Online (AJOL)

    The instruments used for investigation are questionnaire survey, face to face interview and observation. Experimentation was done in the laboratory to investigate physical, chemical and microbiological samples of drinking water from the households in Akinima community. Both primary and secondary data are applied for ...

  6. Simplification of Water Distribution Network Simulation by Topological Clustering – Investigation of its Potential Use in Copenhagen's Water Supply Monitoring and Contamination Contingency Plans

    OpenAIRE

    Kirstein, J.K.; Albrechtsen, H.-J.; Rygaard, M.

    2014-01-01

    Topological clustering was investigated to simplify a complex water distribution network of Copenhagen, Denmark, into recogniz- able water movement patterns. This made it possible to assess the general transport of the water and to suggest strategic sampling locations. Through a topological analysis, the network model was divided into strongly and weakly connected clusters within selected time periods. Steady connected clusters were found by conducting a cluster analysis over all chosen selec...

  7. Interfacial transport phenomena and stability in liquid-metal/water systems: scaling considerations

    International Nuclear Information System (INIS)

    Abdulla, S.; Liu, X.; Anderson, M.; Bonazza, R.; Corradini, M.; Cho, D.

    2001-01-01

    One concept being considered for steam generation in innovative nuclear reactor applications, involves water coming into direct contact with a circulating molten metal. The vigorous agitation of the two fluids, the direct liquid-liquid contact and the consequent large interfacial area give rise to very high heat transfer coefficients and rapid steam generation. For an optimum design of such direct contact heat exchange and vaporization systems, detailed knowledge is necessary of the various flow regimes, interfacial transport phenomena, heat transfer and operational stability. In this paper we describe current results from the first year of this research that studies the transport phenomena involved with the injection of water into molten metals (e.g., lead alloys). In particular, this work discusses scaling considerations related to direct contact heat exchange, our experimental plans for investigation and a test plan for the important experimental parameters; i.e., the water and liquid metal mass flow rates, the liquid metal pool temperature and the ambient pressure of the direct contact heat exchanger. Past experimental work and initial scaling results suggest that our experiments can directly represent the proper liquid metal pool temperature and the water subcooling. The experimental variation in water and liquid metal flow rates and system pressure (1-10 bar), although smaller than the current conceptual system designs, is sufficient to verify the expected scale effects to demonstrate the phenomena. (authors)

  8. Sodium and chloride transport in soft water and hard water acclimated zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Boisen, A M Z; Amstrup, J; Novak, I

    2003-01-01

    While the zebrafish is commonly used for studies of developmental biology and toxicology, very little is known about their osmoregulatory physiology. The present investigation of Na(+) and Cl(-) transport revealed that the zebrafish is able to tolerate extremely low ambient ion concentrations and...

  9. FEATURES OF TRANSPORT OF CERTAIN ELEMENTS IN WATER NORTH CASPIAN

    Directory of Open Access Journals (Sweden)

    E. V. Chujko

    2013-01-01

    Full Text Available Major influence on the form of migration of trace elements in the North Caspian has Volga runoff. The bulk of the elements in the Volga waters carried in the suspended solids. The exception is zinc, transports mainly in dissolved form.In article presents the results of a study of dissolved and suspended forms of zinc, copper, lead, and manganese in the surface water of the North Caspian Sea from 2002 to 2009. On the basis of the received data the ratio of dissolved and suspended forms of trace elements studied. According to calculations, the bulk of the copper, lead and manganese is carried in the suspended solids. Zinc migrates mainly in dissolved form. The dominant form of migration of the metal increases, depending on the season. For zinc, the migrant in the ionic state, and for copper, lead, manganese, transferring primarily in suspension, in the autumn period the increase in the proportion of dissolved (Zn and suspended forms (Cu, Pb, Mn, respectively. Increase in the proportion of ionic forms of metals in the North Caspian occurred episodically in local areas. Over the entire study period the greatest number of excess dissolved form of weighted metal observed in the central part of the shallow zone predustevogo space p. Volga near the exit of the Kirov and Belinsky channels.

  10. Comparative investigation of electronic transport across three-dimensional nanojunctions

    Science.gov (United States)

    Wang, Yun-Peng; Zhang, X.-G.; Fry, J. N.; Cheng, Hai-Ping

    2017-02-01

    We show the thickness-dependent transition from metallic conduction to tunneling in three-dimensional (3D) Ag/Si/Ag nanojunctions through layer-by-layer electronic structure and quantum transport calculations. The transmission coefficients are calculated quantum mechanically within the framework of density functional theory in conjunction with nonequilibrium Green's function techniques. Thin junctions show nearly metallic character with no energy gap opening in Si layers due to the metal-induced interface states, and the transmission is independent of the stacking order of Si layers. An energy gap reemerges for Si layers deeply buried within thick junction, and the decay rate of transmission in this insulating region depends on the stacking order. Complex band analysis indicates that the decay of transmission is not determined by a single exponential constant but also depends on the available number of evanescent states. Calculating the electric resistance from the transmission coefficient requires a 3D generalization of the Landauer formula, which is not unique. We examine two approaches, the Landauer-Büttiker formula, with and without subtraction of the Sharvin resistance, and a semiclassical Boltzmann equation with boundary conditions defined by the transmission coefficients at the junction. We identify an empirical upper limit of ˜0.05 per channel in the transmission coefficient, below which the Landauer-Büttiker formula without the Sharvin resistance correction remains a good approximation. In the high transmission limit, the Landauer-Büttiker formula with Sharvin correction and the semiclassical Boltzmann method reach fair agreement.

  11. Effects of heat and water transport on the performance of polymer electrolyte membrane fuel cell under high current density operation

    International Nuclear Information System (INIS)

    Tabuchi, Yuichiro; Shiomi, Takeshi; Aoki, Osamu; Kubo, Norio; Shinohara, Kazuhiko

    2010-01-01

    Key challenges to the acceptance of polymer electrolyte membrane fuel cells (PEMFCs) for automobiles are the cost reduction and improvement in its power density for compactness. In order to get the solution, the further improvement in a fuel cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFCs has considerable effects on the cell performance. In this study, the impact of heat and water transport on the cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution in MEA between rib and channel area is evaluated by neutron radiography. In order to neglect the effect of liquid water in gas channels and reactant species concentration distribution in the flow direction, the differential cell was used in this study. Experimental results suggested that liquid water under the channel was dramatically changed with rib/channel width. From the numerical study, it is found that the change of liquid water distribution was significantly affected by temperature distribution in MEA between rib and channel area. In addition, not only heat transport but also water transport through the membrane also significantly affected the cell performance under high current density operation.

  12. The influence of water on the structural and transport properties of model ionic liquids.

    Science.gov (United States)

    Spohr, Heidrun V; Patey, G N

    2010-06-21

    Molecular dynamics simulations are used to investigate the influence of water on model ionic liquids. Several models, where the ions vary in size, and in the location of the charge with respect to the center of mass, are considered. Particular attention is focused on the variation in transport properties (diffusion coefficients, shear viscosity, and electrical conductivity) with water concentration. An effort is made to identify the underlying physical reasons for water's influence. The results for our model ionic liquids fall loosely into two categories, depending on the molecular characteristics of the constituent ions. If the ion size disparity is not too large (cation:anion diameter ratio water concentration. This agrees with what is commonly observed experimentally for room temperature ionic liquids (RTILs). For these systems, we do not find changes in the equilibrium structure that can account for the strong influence of water on the transport properties. Rather, by varying the molecular mass of water in our simulations, we demonstrate that the dominant effect of water can be dynamical in origin. In RTIL-water mixtures, the molecular mass of water is generally much less than that of the ions it replaces. These lighter water molecules tend to displace much heavier counterions from the ion coordination shells. This reduces caging and increases the diffusivity, which leads to higher conductivities and lower viscosities. For models with a larger ion size disparity (3:1), or in charge-off-center systems, where strong directional ion pairs are important in the pure ionic liquid, the behavior can be quite different. In these systems, the diffusion coefficients and electrical conductivity can still display conventional behavior and increase when water is added even though the reasons for this can be more complex than in the simpler cases noted above. However, in these systems the viscosity can increase, sometimes quite steeply, with increasing water concentration. We

  13. Investigation of metal concentration in water using PIXE

    International Nuclear Information System (INIS)

    Prajapati, P.K.; Chakraborty, S.; Tiwary, S.S.; Majumder, C.; Sharma, H.P.; Kumar, A.; Singh, K.P.; Shivcharan; Mohanty, B.P.

    2017-01-01

    Availability of clean drinking water is an essential requirement for human health. The Ganga water is being widely used for drinking and irrigation purposes in many cities situated near the bank of the river, which effect the human health. Hence investigation of toxic elements of Ganga water is very important. PIXE (Particle Induce X-ray Emission) is well known and useful technique for finding out qualitative and quantitative analysis of various samples (taken from environment) and may contains about 30-50 elements together with concentration of about 1ppb. The elemental analysis depends on the inner-shell ionization process and measurement of the X-ray yield of the samples. For the present investigation, samples of Ganga water were collected from Varanasi and Allahabad

  14. Does water content or flow rate control colloid transport in unsaturated porous media?

    Science.gov (United States)

    Knappenberger, Thorsten; Flury, Markus; Mattson, Earl D; Harsh, James B

    2014-04-01

    Mobile colloids can play an important role in contaminant transport in soils: many contaminants exist in colloidal form, and colloids can facilitate transport of otherwise immobile contaminants. In unsaturated soils, colloid transport is, among other factors, affected by water content and flow rate. Our objective was to determine whether water content or flow rate is more important for colloid transport. We passed negatively charged polystyrene colloids (220 nm diameter) through unsaturated sand-filled columns under steady-state flow at different water contents (effective water saturations Se ranging from 0.1 to 1.0, with Se = (θ - θr)/(θs - θr)) and flow rates (pore water velocities v of 5 and 10 cm/min). Water content was the dominant factor in our experiments. Colloid transport decreased with decreasing water content, and below a critical water content (Se colloid transport was inhibited, and colloids were strained in water films. Pendular ring and water film thickness calculations indicated that colloids can move only when pendular rings are interconnected. The flow rate affected retention of colloids in the secondary energy minimum, with less colloids being trapped when the flow rate increased. These results confirm the importance of both water content and flow rate for colloid transport in unsaturated porous media and highlight the dominant role of water content.

  15. Transport and Retention of Concentrated Oil-in-Water Emulsions in Sandy Porous Media

    Science.gov (United States)

    Muller, K.; Esahani, S. G.; Steven, C. C.; Ramsburg, A.

    2015-12-01

    Oil-in-water emulsions are widely employed to promote biotic reduction of contaminants; however, emulsions can also be used to encapsulate and deliver active ingredients required for long-term subsurface treatment. Our research focuses on encapsulating alkalinity-releasing particles in oil-in-water emulsions for sustained control of subsurface pH. Typical characteristics of these emulsions include kinetically stable for >20 hr; 20% soybean oil; 1 g/mL density; 8-10 cP viscosity; and 1.5 μm droplet d50, with emulsions developed for favorable subsurface delivery. The viscosity of the oil-in-water emulsions was found to be a function of oil content. Ultimately we aim to model both emulsion delivery and alkalinity release (from retained emulsion droplets) to provide a description of pH treatment. Emulsion transport and retention was investigated via a series of 1-d column experiments using varying particle size fractions of Ottawa sand. Emulsions were introduced for approximately two pore volumes followed by a flush of background solution (approx. ρ=1 g/mL; μ=1cP). Emulsion breakthrough curves exhibit an early fall on the backside of the breakthrough curve along with tailing. Deposition profiles are found to be hyper-exponential and unaffected by extended periods of background flow. Particle transport models established for dilute suspensions are unable to describe the transport of the concentrated emulsions considered here. Thus, we explore the relative importance of additional processes driving concentrated droplet transport and retention. Focus is placed on evaluating the role of attachment-detachment-straining processes, as well as the influence of mixing from both viscous instabilities and variable water saturation due to deposited mass.

  16. Water information bulletin No. 30 geothermal investigations in Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J.C.; Johnson, L.L.; Anderson, J.E.; Spencer, S.G.; Sullivan, J.F.

    1980-06-01

    There are 899 thermal water occurrences known in Idaho, including 258 springs and 641 wells having temperatures ranging from 20 to 93/sup 0/C. Fifty-one cities or towns in Idaho containing 30% of the state's population are within 5 km of known geothermal springs or wells. These include several of Idaho's major cities such as Lewiston, Caldwell, Nampa, Boise, Twin Falls, Pocatello, and Idaho Falls. Fourteen sites appear to have subsurface temperatures of 140/sup 0/C or higher according to the several chemical geothermometers applied to thermal water discharges. These include Weiser, Big Creek, White Licks, Vulcan, Roystone, Bonneville, Crane Creek, Cove Creek, Indian Creek, and Deer Creek hot springs, and Raft River, Preston, and Magic Reservoir areas. These sites could be industrial sites, but several are in remote areas away from major transportation and, therefore, would probably be best utilized for electrical power generation using the binary cycle or Magma Max process. Present uses range from space heating to power generation. Six areas are known where commercial greenhouse operations are conducted for growing cut and potted flowers and vegetables. Space heating is substantial in only two places (Boise and Ketchum) although numerous individuals scattered throughout the state make use of thermal water for space heating and private swimming facilities. There are 22 operating resorts using thermal water and two commercial warm-water fish-rearing operations.

  17. 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.

  18. Investigating water soluble organic aerosols: Sources and evolution

    Science.gov (United States)

    Hecobian, Arsineh N.

    Many studies are being conducted on the different properties of organic aerosols (OA-s) as it is first emitted into the atmosphere and the consequent changes in these characteristics as OA-s age and secondary organic aerosol (SOA) is produced and in turn aged. This thesis attempts to address some of the significant and emerging issues that deal with the formation and transformation of water-soluble organic aerosols in the atmosphere. First, a proven method for the measurement of gaseous sulfuric acid, negative ion chemical ionization mass spectrometry (CIMS), has been modified for fast and sensitive measurements of particulate phase sulfuric acid (i.e. sulfate). The modifications implemented on this system have also been the subject of preliminary verifications for measurements of aerosol phase oxalic acid (an organic acid). Second, chemical and physical characteristics of a wide range of biomass-burning plumes intercepted by the NASA DC-8 research aircraft during the three phases of the ARCTAS experiment are presented here. A statistical summary of the emission (or enhancement) ratios relative to carbon monoxide is presented for various gaseous and aerosol species. Extensive investigations of fire plume evolutions were undertaken during the second part of this field campaign. For four distinct Boreal fires, where plumes were intercepted by the aircraft over a wide range of down-wind distances, emissions of various compounds and the effect of aging on them were investigated in detail. No clear evidence of production of secondary compounds (e.g., WSOC and OA) was observed. High variability in emissions between the different plumes may have obscured any clear evidence of changes in the mass of various species with increasing plume age. Also, the lack if tropospheric oxidizing species (e.g., O3 and OH) may have contributed to the lack of SOA formation. Individual intercepts of smoke plumes in this study were segregated by source regions. The normalized excess mixing

  19. Finite-bias electronic transport of molecules in a water solution

    KAUST Repository

    Rungger, Ivan

    2010-06-04

    The effects of water wetting conditions on the transport properties of molecular nanojunctions are investigated theoretically by using a combination of empirical-potential molecular-dynamics and first-principles electronic-transport calculations. These are at the level of the nonequilibrium Green’s-function method implemented for self-interaction corrected density-functional theory. We find that water effectively produces electrostatic gating to the molecular junction with a gating potential determined by the time-averaged water dipole field. Such a field is large for the polar benzene-dithiol molecule, resulting in a transmission spectrum shifted by about 0.6 eV with respect to that of the dry junction. The situation is drastically different for carbon nanotubes (CNTs). In fact, because of their hydrophobic nature the gating is almost negligible so that the average transmission spectrum of wet Au/CNT/Au junctions is essentially the same as that in dry conditions. This suggests that CNTs can be used as molecular interconnects also in water-wet situations, for instance, as tips for scanning tunnel microscopy in solution or in biological sensors.

  20. Numerical Modeling of Water Flow and Salt Transport in Bare Saline Soil Subjected to Transient Evaporation

    Science.gov (United States)

    Geng, X.; Boufadel, M.; Saleh, F. S.

    2014-12-01

    It has been found that evaporation over bare soil plays an important role in subsurface solute transport processes. A numerical study, based on a density-dependent variably saturated groundwater flow model MARUN, was conducted to investigate subsurface flow and salt transport in bare saline aquifers subjected to transient evaporation. The bulk aerodynamic formulation was adopted to simulate transient evaporation rate at ground surface. Subsurface flow pattern, moisture distribution, and salt migration were quantified. Key factors likely affecting this process, including saturated hydraulic conductivity, capillary drive, air humidity, and surrounding water supply, were examined. The results showed that evaporation induced an upward flow pattern, which led to a high saline plume formed beneath the evaporation zone. In absence of surrounding water supply, as the humidity between the ground surface and air tended to equilibrium, evaporation-induced density gradient generated pore water circulations around the plume edge and caused the salt to migrate downwards with "finger" shapes. It was found that capillary properties and atmospheric condition had significant impacts on subsurface moisture distribution and salt migration in response to the evaporation. Larger capillary fringe and/or lower air humidity would allow evaporation to extract more water from the ground. It would induce a larger and denser saline plume formed beneath the evaporation zone. The results also suggested that the presence of the surrounding water supply (represented as a constant water table herein) could provide a steady evaporation rate at the ground surface; meanwhile, in response to the evaporation, a hydraulic gradient was formed from the water supply boundary, which induced an inclined upper saline plume with greater density far from the supply boundary.

  1. How does fiction reading influence empathy? An experimental investigation on the role of emotional transportation

    NARCIS (Netherlands)

    Bal, P.M.; Veltkamp, M.

    2013-01-01

    The current study investigated whether fiction experiences change empathy of the reader. Based on transportation theory, it was predicted that when people read fiction, and they are emotionally transported into the story, they become more empathic. Two experiments showed that empathy was influenced

  2. Investigation on Kombiterm GE Domestic Hot Water Tank

    DEFF Research Database (Denmark)

    Heller, Alfred; Heuer, Andreas Walter

    1996-01-01

    Investigation of a hot water tank with a high heat exchanger spiral with a small pipe diameter in the upper part of the heat exchanger spiral and a large pipe diameter in the lower part of the heat exchanger spiral in cooperation with Kãhler&Breum Beholder- og Maskinfabrik K/S. First preprint of ...

  3. Investigations on stratification devices for hot water stores

    DEFF Research Database (Denmark)

    Andersen, Elsa; Furbo, Simon; Hampel, Matthias

    2008-01-01

    The significance of the thermal stratification for the energy efficiency of small solar-thermal hot water heat stores is pointed out. Exemplary the thermal stratification build-up with devices already marketed as well as with devices still in development has been investigated experimentally...

  4. investigating water absorption and thickness swelling tendencies of ...

    African Journals Online (AJOL)

    HOD

    INVESTIGATING WATER ABSORPTION AND THICKNESS SWELLING TENDENCIES OF POLYMERIC COMPOSITE … O. Adekomaya & K. Adama. Nigerian Journal of Technology,. Vol. 37, No. 1, January 2018. 169. Table 2: Physical and thermal properties of epoxy resin materials (Adapted from manufacturer data sheet).

  5. Hydrogeochemical transport modeling of 24 years of Rhine water infiltration in the dunes of the Amsterdam Water Supply.

    NARCIS (Netherlands)

    van Breukelen, B.M.; Appelo, C.A.J.; Olsthoorn, T.N.

    1998-01-01

    Water quality changes were modelled along a flowpath in a plume of artificially recharged, pretreated Rhine water in the dunes of the Amsterdam Water Supply, after 24 years of infiltration. The hydrogeochemical transport model PHREEQC was extended with dispersion/diffusion and kinetics for selected

  6. Investigation of radiological properties and water equivalency of PRESAGE dosimeters.

    Science.gov (United States)

    Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Adamovics, John; Bosi, Stephen; Kim, Jung-Ha; Baldock, Clive

    2011-04-01

    PRESAGE is a dosimeter made of polyurethane, which is suitable for 3D dosimetry in modern radiation treatment techniques. Since an ideal dosimeter is radiologically water equivalent, the authors investigated water equivalency and the radiological properties of three different PRESAGE formulations that differ primarily in their elemental compositions. Two of the formulations are new and have lower halogen content than the original formulation. The radiological water equivalence was assessed by comparing the densities, interaction probabilities, and radiation dosimetry properties of the three different PRESAGE formulations to the corresponding values for water. The relative depth doses were calculated using Monte Carlo methods for 50, 100, 200, and 350 kVp and 6 MV x-ray beams. The mass densities of the three PRESAGE formulations varied from 5.3% higher than that of water to as much as 10% higher than that of water for the original formulation. The probability of photoelectric absorption in the three different PRESAGE formulations varied from 2.2 times greater than that of water for the new formulations to 3.5 times greater than that of water for the original formulation. The mass attenuation coefficient for the three formulations is 12%-50% higher than the value for water. These differences occur over an energy range (10-100 keV) in which the photoelectric effect is the dominant interaction. The collision mass stopping powers of the relatively lower halogen-containing PRESAGE formulations also exhibit marginally better water equivalency than the original higher halogen-containing PRESAGE formulation. Furthermore, the depth dose curves for the lower halogen-containing PRESAGE formulations are slightly closer to that of water for a 6 MV beam. In the kilovoltage energy range, the depth dose curves for the lower halogen-containing PRESAGE formulations are in better agreement with water than the original PRESAGE formulation. Based on the results of this study, the new

  7. Review on the development of unidirectional water-transport fibers and fabrics

    Directory of Open Access Journals (Sweden)

    Yaqian XIAO

    2017-08-01

    Full Text Available Unidirectional water-transport fabric is a kind of functional fiber assembles used to realize unidirectional conduction of liquid water, and it could be used for the design and development of clothing with the function of thermal-wet comfort. The development of unidirectional water-transport fabrics from the mechanism of the unidirectional water-transport, selection of fiber and preparation method is summarized. Five key methods to achieve the unidirectional water-transport effect have been reviewed, including the designing of fabric structure, chemical finishing, plasma treatment, electro spinning and photocatalytic treatment. According to the current problems in the research on unidirectional water-transfer fabric, it is proposed that multi-functional unidirectional water-transfer fabrics should be developed by post-treatment finishing technology with adding special functional additives to expand the practical applications.

  8. Experimental and numerical investigation of the coupling of turbulence and sediment transport over dunes

    Science.gov (United States)

    Schmeeckle, M. W.; Leary, K. P.

    2016-12-01

    We investigate the spatiotemporal coupling of sediment transport over dunes using a turbulence- and particle-resolving numerical model and high-speed video in a laboratory flume. The model utilizes the Large Eddy Simulation (LES) for the fluid turbulence and a Discrete Element Method (DEM) simulation for the sediment. Previous experiments assessing the effects of flow separation on downstream fluid turbulent structures and bedload transport suggest that localized, intermittent, high-magnitude transport events, called permeable splat events, play an important role in both downstream and cross-stream transport near flow reattachment. The flume was lined with 17 concrete ripples that had a 2 cm high crest and were 30 cm long. A high-speed camera observed sediment transport along the entirety of the bedform at 250 Hz. Downstream and vertical fluid velocity was observed at 1mm and 3 mm above the bed using Laser Doppler Velocitmetry (LDV) at 15 distances along bedform profile. As observed in our previous backward-facing step experiments and simulations, mean downstream fluid velocity increases nonlinearly with increasing distance along the ripple. Observed sediment transport, however, increases linearly with increasing distance along the ripple with an exception at the crest of the bedform, where both mean downstream fluid velocity and sediment transport decrease significantly. Previous experiments assessing only the effect of flow separation showed that calculating sediment transport as a function of boundary shear stress using a Meyer-Peter Müller type equation, produced a zone of underestimated transport near flow reattachment. Results reported here show that calculating sediment transport in this way underestimates observed sediment transport along the entire profile of the bedform, not just near flow reattachment. Preliminary sediment transport time-series data show a zone of high-magnitude cross-stream transport near flow reattachment, suggesting that permeable

  9. Development and optimization of radiographic and tomographic methods for characterization of water transport processes in PEM fuel cell materials

    International Nuclear Information System (INIS)

    Markoetter, Henning

    2013-01-01

    perforated MPL/GDL-materials were investigated. It had been shown in complementary measurements that depending on process parameters perforated MPL/GDL materials can have either a positive or in other cases a negative impact on the cell performance (gains of up to 20 % vs. losses of same magnitude). The water transport was found to be responsible for the different behavior. At its best, the perforations have a drainage effect which facilitates effective water removal. In other cases a flooding of the whole local pore area around the perforation was observed. This area was obviously heat affected by laser perforation procedure and showed a hydrophilic behavior. The transport through the perforations was also found to be bidirectional. In this work, specially adapted measuring techniques were applied to analyze various aspects of water management. For example the combination of dynamic radiographic and three-dimensional tomographic measurements has been proven as valuable method to interpret transport phenomena in terms of the underlying cell structure. On top of that a method is applied, which allows for an increased spatial resolution in tomography and the easy switch between radiographic and tomographic measure mode. By comparing the tomographic data of the cell measured subsequent to operation with the dry reference state it was possible to extract the three-dimensional quasi in situ water distribution. This allows for more detailed analyses, for example, statistical water cluster size distributions. The extracted water distribution was also used by a group at the ZSW Ulm for the model validation of a grand canonical Monte Carlo simulation.

  10. Wearable Sensors in Transportation - Exploratory Advanced Research Program Initial Stage Investigation

    Science.gov (United States)

    2016-03-01

    This report summarizes an initial stage investigation into wearable sensors for transportation research : applications. The Federal Highway Administration (FHWA) has observed significant activity in this area and : seeks to obtain an understanding of...

  11. New methods For Modeling Transport Of Water And Solutes In Soils

    DEFF Research Database (Denmark)

    Møldrup, Per

    Recent models for water and solute transport in unsaturated soils have been mechanistically based but numerically very involved. This dissertation concerns the development of mechanistically-based but numerically simple models for calculating and analyzing transport of water and solutes in soil s...

  12. How does fiction reading influence empathy? An experimental investigation on the role of emotional transportation.

    Science.gov (United States)

    Bal, P Matthijs; Veltkamp, Martijn

    2013-01-01

    The current study investigated whether fiction experiences change empathy of the reader. Based on transportation theory, it was predicted that when people read fiction, and they are emotionally transported into the story, they become more empathic. Two experiments showed that empathy was influenced over a period of one week for people who read a fictional story, but only when they were emotionally transported into the story. No transportation led to lower empathy in both studies, while study 1 showed that high transportation led to higher empathy among fiction readers. These effects were not found for people in the control condition where people read non-fiction. The study showed that fiction influences empathy of the reader, but only under the condition of low or high emotional transportation into the story.

  13. How Does Fiction Reading Influence Empathy? An Experimental Investigation on the Role of Emotional Transportation

    Science.gov (United States)

    Bal, P. Matthijs; Veltkamp, Martijn

    2013-01-01

    The current study investigated whether fiction experiences change empathy of the reader. Based on transportation theory, it was predicted that when people read fiction, and they are emotionally transported into the story, they become more empathic. Two experiments showed that empathy was influenced over a period of one week for people who read a fictional story, but only when they were emotionally transported into the story. No transportation led to lower empathy in both studies, while study 1 showed that high transportation led to higher empathy among fiction readers. These effects were not found for people in the control condition where people read non-fiction. The study showed that fiction influences empathy of the reader, but only under the condition of low or high emotional transportation into the story. PMID:23383160

  14. Study on lead transportation in air-water-paddy system with 210Pb as tracer

    International Nuclear Information System (INIS)

    Li Shuding; Zhang Hairong; Ma Xuejun

    1987-08-01

    With 210 PbCl 2 as tracer, a research into lead sources in brown rice, lead distribution in soil and rice, lead chemical forms in soil and their change with time, availability of soil for rice and effect of soil pH on the Pb adsorption was carried out in air-water-paddy system near cities and towns located upper and middle reaches of Liaohe River, northeastern China. Test soil was light acid meadow brown soil. The Pb proportions in rice grain derived from the soil, airborne dust and irrigation water and the transportation pathway to brown rice were investigated. Transportation coefficients of Pb in the system were determined by tracer experiment. It was indicated that the Pb concentration in rice root, the Pb concentration and its distribution in the soil are main factors effecting Pb transportation to rice. Based on the simulation test, mathematical model for computing soil environmental capacity of Pb in the system is put forward. The soil environmental capacity of Pb computed is 1600 - 1700 ppm, i.e. 3.6 - 3.8 t/ha. The computed result was in agreement with the observed. The mathematical model was also used to compute soil enviromental capacity of those heavy metal corresponding respectively with 203 Hg, 115+115m Cd, 65 Zn, 51 Cr, 65 Ni, 60 Co etc

  15. Development of a Life Cycle Inventory of Water Consumption Associated with the Production of Transportation Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, David J. [Argonne National Lab. (ANL), Argonne, IL (United States); Cai, Hao [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Keisman, Jennifer [Argonne National Lab. (ANL), Argonne, IL (United States); Wu, May [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer [Argonne National Lab. (ANL), Argonne, IL (United States); Sullivan, John L. [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, Amgad [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Michael [Argonne National Lab. (ANL), Argonne, IL (United States); Keisman, Jennifer [American Association for the Advancemetn of Science (AAAS), Washington, DC (United States)

    2015-10-01

    The production of all forms of energy consumes water. To meet increased energy demands, it is essential to quantify the amount of water consumed in the production of different forms of energy. By analyzing the water consumed in different technologies, it is possible to identify areas for improvement in water conservation and reduce water stress in energy-producing regions. The transportation sector is a major consumer of energy in the United States. Because of the relationships between water and energy, the sustainability of transportation is tied to management of water resources. Assessment of water consumption throughout the life cycle of a fuel is necessary to understand its water resource implications. To perform a comparative life cycle assessment of transportation fuels, it is necessary first to develop an inventory of the water consumed in each process in each production supply chain. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can used to estimate the full life-cycle environmental impacts of various transportation fuel pathways from wells to wheels. GREET is currently being expanded to include water consumption as a sustainability metric. The purpose of this report was to document data sources and methodologies to estimate water consumption factors (WCF) for the various transportation fuel pathways in GREET. WCFs reflect the quantity of freshwater directly consumed per unit production for various production processes in GREET. These factors do not include consumption of precipitation or low-quality water (e.g., seawater) and reflect only water that is consumed (i.e., not returned to the source from which it was withdrawn). The data in the report can be combined with GREET to compare the life cycle water consumption for different transportation fuels.

  16. Investigation of the core melt accident in light water reactors

    International Nuclear Information System (INIS)

    Koerber, H.

    1980-01-01

    In the thesis the core melt accident, heating up and collapsing of the reactor core were investigated. The most important parameters of influence were found and their effect on the development of the accident were shown. A causal diagram was developed representing the great number of events occurring in the course of the core melt accident as well as their mutual dependences. Models were developed and applied for a detailed description of the collapse process, melting of materials, heat and material transport at flow-off of the melted mass and for taking into account steam blocking in the destroyed core sections. (orig.) [de

  17. Source investigation methods to determine PCE transport pathways to groundwater at dry cleaners in Chicao, California

    International Nuclear Information System (INIS)

    Taylor, J.; Venus, T.; Lubke, R.; Graydon, J.; Riddle, G.

    1992-01-01

    Tetrachloroethylene (PCE) contamination of groundwater underlying Chico, California has caused the closure of 5 public water supply wells, degraded the water quality in 23 private wells, and rendered up to 32,000 acre-ft of groundwater non-potable. The principal source of the PCE is believed to be waste disposal from dry cleaning operations. The investigative tools employed to characterize the distribution of PCE in the vadose zone and shallow groundwater at dry cleaner sites included: soil gas surveys; soil core sampling; depth-discrete groundwater sampling using the HydroPunch II sampler; groundwater samples obtained from monitoring wells; soil gas samples obtained from vapor monitoring wells; and dye-testing, video surveying, and high-pressure flush sampling of sanitary sewer lines. Quantitative results of field gas chromatographic (GC) analysis of soil vapor, groundwater, sanitary sewer flow, and soil samples compared favorably with concentrations reported from split samples analyzed by a California-certified laboratory. Results from the field GC analyses were used to guide the selection of monitoring well location, depth, and screened interval, and reduced the number of samples submitted to the laboratory. Results show that while modest levels of PCE (10-100 ppb) were found in soil and shallow groundwater at the sites, substantial concentrations (up to 0.1%) were found in sewer flush samples taken downstream from one of the active sites. PCE in sewer lines is believed to originate from the disposal of PCE-saturated wastewaters from the dry cleaners. This study indicates that employing several methods of contaminant detection increases the potential for source confirmation and determination of contaminant transport pathways. The high concentrations of PCE found in sewer lines downstream from dry cleaners in this study indicate that priority should be given early in the project to investigations of sanitary sewers

  18. Solute transport in coupled inland-coastal water systems. General conceptualisation and application to Forsmark

    International Nuclear Information System (INIS)

    Jarsjoe, Jerker; Destouni, Georgia; Persson, Klas; Prieto, Carmen

    2007-12-01

    fraction of mass released in a cell that reaches the considered recipient. Results showed that average delivery factors, representing the whole catchment and equalling expected delivery factors in the probabilistic case, can exhibit considerable differences between transport pathway scenarios (I) and (II). However, the magnitude of the differences in average delivery factors (between transport pathway scenarios as well as between considered release points) depends on the actual attenuation rates (i.e. λ-values). This is because for low λ (for Forsmark: λ 10/y) only a small fraction of the mass reaches the coast regardless of release point and scenario. The above results imply that, in general, mass delivery factors to recipients are sensitive to both pathways and entrance points or areas in the Quaternary deposits of Forsmark, with for instance a remaining key question being to which extent the deep groundwater transport pathway to the coast includes the surface water system and/or Quaternary deposits-bedrock interface zone. However, given more specific sub-catchment areas and possible ranges of attenuation rates from parallel studies, the present analyses also show that robust predictions regarding e.g. mass delivery can in some cases be obtained despite considerable pathway and entrance point uncertainties. Because such cases then can be excluded from further investigation, it appears that specific transport analyses that consider relevant combinations of possible release points, transport pathway scenarios and attenuation rates can be used for delimiting specific priority regions, where remaining uncertainties are high and further experimental investigations and/or monitoring hence may be needed to reduce the uncertainties

  19. Transients of Water Distribution and Transport in PEM Fuel Cells

    KAUST Repository

    Hussaini, Irfan S.

    2009-01-01

    The response of polymer electrolyte membrane (PEM) fuel cells to a step change in load is investigated experimentally in this work. Voltage undershoot, a characteristic feature of transient response following a step increase in current, is due to transients of water distribution in the membrane and ionomers occurring at subsecond time scales. The use of humidified reactants as a means to control the magnitude of voltage undershoot is demonstrated. Further, the response under a step decrease in current density is explored to determine the existence of hysteresis. Under sufficiently humidified conditions, the responses under forward and reverse step changes are symmetric, but under low relative humidity conditions, voltage undershoot is twice as large as the overshoot. © 2009 The Electrochemical Society.

  20. Transients of Water Distribution and Transport in PEFCs

    KAUST Repository

    Hussaini, Irfan

    2008-01-01

    Response of PEM fuel cells to a step-change in load is investigated experimentally in this work. Voltage undershoot, a characteristic feature of such transient response, is shown to be due to transients of water distribution in membrane phase occurring at sub-second time scales. Use of humidified reactants as a means to control magnitude of voltage undershoot has been demonstrated. Constant stoichiometry operation under certain current-step conditions is found to result in reactant starvation, potentially leading to cell shut down. Further, response under step decrease in current density has been explored to determine existence of hysteresis. Under sufficiently humidified conditions, response under forward and reverse step changes are found to be symmetric, but under low RH conditions, voltage undershoot is found to be twice as large as the overshoot. © The Electrochemical Society.

  1. Effect of biochar on soil structural characteristics: water retention and gas transport

    DEFF Research Database (Denmark)

    Sun, Zhencai; Møldrup, Per; Vendelboe, Anders Lindblad

    Biochar addition to agricultural soil has been reported to reduce climate gas emission, as well as improve soil fertility and crop productivity. Little, however, is known about biochar effects on soil structural characteristics. This study investigates if biochar-application changes soil structural...... characteristics, as indicated from water retention and gas transport measurements on intact soil samples. Soil was sampled from a field experiment on a sandy loam with four control plots (C) without biochar and four plots (B) with incorporated biochar at a rate of 20 tons per hectare (plot size, 6 x 8 m). The C......-gas diffusivity on intact 100cm3 soil samples (5 replicates in each plot). We found that biochar application significantly decreased soil bulk density, hereby creating higher porosity. At the same soil-water matric potential, all the soil-gas phase parameters (air-filled porosity, air permeability and gas...

  2. COPTEM: A Model to Investigate the Factors Driving Crude Oil Pipeline Transportation Emissions.

    Science.gov (United States)

    Choquette-Levy, Nicolas; Zhong, Margaret; MacLean, Heather; Bergerson, Joule

    2018-01-02

    Previous transportation fuel life cycle assessment studies have not fully accounted for the full variability in the crude oil transport stage, for example, transporting a light crude through a high-diameter pipeline, vs transporting a heavy crude through a small-diameter pipeline. We develop a first-principles, fluid mechanics-based crude oil pipeline transportation emissions model (COPTEM) that calculates the greenhouse gas (GHG) emissions associated with pipeline transport as a function of crude oil parameters, pipeline dimensions, and external factors. Additionally, we estimate the emissions associated with the full life cycle of pipeline construction, maintenance, and disposal. This model is applied to an inventory of 62 major Canadian and U.S. pipelines (capacity greater than 100 000 barrels/day) to estimate the variability of GHG emissions associated with pipeline transportation. We demonstrate that pipeline GHG emissions intensities range from 0.23 to 20.3 g CO 2 e/(bbl·km), exhibiting considerably greater variability than data reported in other studies. A sensitivity analysis demonstrates that the linear velocity of crude transport and pipeline diameter are the most impactful parameters driving this variability. To illustrate one example of how COPTEM can be used, we develop an energy efficiency gap analysis to investigate the possibilities for more efficient pipeline transport of crude oil.

  3. Numerical and Experimental Investigation of Turbulent Transport Control via Shaping of Radial Plasma Flow Profiles

    Energy Technology Data Exchange (ETDEWEB)

    Gilmore, Mark Allen [Univ. of New Mexico, Albuquerque, NM (United States)

    2017-02-05

    Turbulence, and turbulence-driven transport are ubiquitous in magnetically confined plasmas, where there is an intimate relationship between turbulence, transport, instability driving mechanisms (such as gradients), plasma flows, and flow shear. Though many of the detailed physics of the interrelationship between turbulence, transport, drive mechanisms, and flow remain unclear, there have been many demonstrations that transport and/or turbulence can be suppressed or reduced via manipulations of plasma flow profiles. This is well known in magnetic fusion plasmas [e.g., high confinement mode (H-mode) and internal transport barriers (ITB’s)], and has also been demonstrated in laboratory plasmas. However, it may be that the levels of particle transport obtained in such cases [e.g. H-mode, ITB’s] are actually lower than is desirable for a practical fusion device. Ideally, one would be able to actively feedback control the turbulent transport, via manipulation of the flow profiles. The purpose of this research was to investigate the feasibility of using both advanced model-based control algorithms, as well as non-model-based algorithms, to control cross-field turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles. The University of New Mexico was responsible for the experimental portion of the project, while our collaborators at the University of Montana provided plasma transport modeling, and collaborators at Lehigh University developed and explored control methods.

  4. Ebullition, Plant-Mediated Transport, and Subsurface Horizontal Water Flow Dominate Methane Transport in an Arctic Sphagnum Bog

    Science.gov (United States)

    Wehr, R. A.; McCalley, C. K.; Logan, T. A.; Chanton, J.; Crill, P. M.; Rich, V. I.; Saleska, S. R.

    2017-12-01

    Emission of the greenhouse gas methane from wetlands is of prime concern in the prediction of climate change - especially emission associated with thawing permafrost, which may drive a positive feedback loop of emission and warming. In addition to the biochemistry of methane production and consumption, wetland methane emission depends critically on the transport mechanisms by which methane moves through and out of the ecosystem. We therefore developed a model of methane biochemistry and transport for a sphagnum bog representing an intermediate permafrost thaw stage in Stordalen Mire, Sweden. In order to simultaneously reproduce measured profiles of both the concentrations and isotopic compositions of both methane and carbon dioxide in the peat pore water (Fig. 1) - as well as the surface methane emission - it was necessary for the model to include ebullition, plant-mediated transport via aerenchyma, and subsurface horizontal water flow. Diffusion of gas through the pore water was relatively unimportant. As a result, 90% of the produced methane escaped the wetland rather than being consumed by methanotrophic organisms in the near-surface pore water. Our model provides a comprehensive picture of methane emission from this bog site by quantifying the vertical profiles of: acetoclastic methanogenesis, hydrogenotrophic methanogenesis, methane oxidation, aerobic respiration, ebullition, plant-mediated transport, subsurface horizontal water flow, and diffusion.

  5. Visualization of root water uptake: quantification of deuterated water transport in roots using neutron radiography and numerical modeling.

    Science.gov (United States)

    Zarebanadkouki, Mohsen; Kroener, Eva; Kaestner, Anders; Carminati, Andrea

    2014-10-01

    Our understanding of soil and plant water relations is limited by the lack of experimental methods to measure water fluxes in soil and plants. Here, we describe a new method to noninvasively quantify water fluxes in roots. To this end, neutron radiography was used to trace the transport of deuterated water (D2O) into roots. The results showed that (1) the radial transport of D2O from soil to the roots depended similarly on diffusive and convective transport and (2) the axial transport of D2O along the root xylem was largely dominated by convection. To quantify the convective fluxes from the radiographs, we introduced a convection-diffusion model to simulate the D2O transport in roots. The model takes into account different pathways of water across the root tissue, the endodermis as a layer with distinct transport properties, and the axial transport of D2O in the xylem. The diffusion coefficients of the root tissues were inversely estimated by simulating the experiments at night under the assumption that the convective fluxes were negligible. Inverse modeling of the experiment at day gave the profile of water fluxes into the roots. For a 24-d-old lupine (Lupinus albus) grown in a soil with uniform water content, root water uptake was higher in the proximal parts of lateral roots and decreased toward the distal parts. The method allows the quantification of the root properties and the regions of root water uptake along the root systems. © 2014 American Society of Plant Biologists. All Rights Reserved.

  6. PHAST--a program for simulating ground-water flow, solute transport, and multicomponent geochemical reactions

    Science.gov (United States)

    Parkhurst, David L.; Kipp, Kenneth L.; Engesgaard, Peter; Charlton, Scott R.

    2004-01-01

    The computer program PHAST simulates multi-component, reactive solute transport in three-dimensional saturated ground-water flow systems. PHAST is a versatile ground-water flow and solute-transport simulator with capabilities to model a wide range of equilibrium and kinetic geochemical reactions. The flow and transport calculations are based on a modified version of HST3D that is restricted to constant fluid density and constant temperature. The geochemical reactions are simulated with the geochemical model PHREEQC, which is embedded in PHAST. PHAST is applicable to the study of natural and contaminated ground-water systems at a variety of scales ranging from laboratory experiments to local and regional field scales. PHAST can be used in studies of migration of nutrients, inorganic and organic contaminants, and radionuclides; in projects such as aquifer storage and recovery or engineered remediation; and in investigations of the natural rock-water interactions in aquifers. PHAST is not appropriate for unsaturated-zone flow, multiphase flow, density-dependent flow, or waters with high ionic strengths. A variety of boundary conditions are available in PHAST to simulate flow and transport, including specified-head, flux, and leaky conditions, as well as the special cases of rivers and wells. Chemical reactions in PHAST include (1) homogeneous equilibria using an ion-association thermodynamic model; (2) heterogeneous equilibria between the aqueous solution and minerals, gases, surface complexation sites, ion exchange sites, and solid solutions; and (3) kinetic reactions with rates that are a function of solution composition. The aqueous model (elements, chemical reactions, and equilibrium constants), minerals, gases, exchangers, surfaces, and rate expressions may be defined or modified by the user. A number of options are available to save results of simulations to output files. The data may be saved in three formats: a format suitable for viewing with a text editor; a

  7. Proposed water-supply investigations in Sidamo Province, Ethiopia

    Science.gov (United States)

    Phoenix, David A.

    1966-01-01

    The present report describes the results of an air and ground hydrologic reconnaissance of some 32,000 square kilometers in Sidamo Province of southern Ethiopia. Existing (1966) water resources developments, chiefly for livestock and village supplies, include surface reservoirs, a few drilled wells, several clusters of dug wells in the Mega area, several scattered springs, and the perennial Dawa Parma River. Surface-water reservoirs range from hand-dug ponds of a few hundred cubic meters capacity to large machine-constructed excavations built to hold 62,000 cubic meters of water. All the existing drilled wells tap saturated alluvium at depths of less than 120 meters. The dug wells tap water-bearing zones in tuffaceous lacustrine deposits or stream-channel alluvium generally at depths of less than 30 meters. The springs mostly rise from fractured Precambrian quartzite and individual discharges are all less than 75 liters per minute. The report also outlines the terms of reference for a longer term water-resources investigation of the region including staffing, housing and equipment requirements and other logistic support.

  8. Investigation and Quantification of Water Track Networks in Boreal Regions Using Remote Sensing and Geophysical Data

    Science.gov (United States)

    Mendbayar, U.; Misra, D.; Gupta, T.; Ghosh, T.

    2015-12-01

    Water tracks are the most prominent drainage pathways that route water through the soil over permafrost in the polar environment and thus play a major role in hydrology, geomorphology, and geochemistry of the polar ecosystem. Existing literature on water tracks is limited and is largely confined to tundra areas devoid of vegetation. The objective of this study is to initiate the investigation of water tracks in thickly vegetated boreal regions, many of which contain predominant engineered infrastructures. The ancillary objectives include the development of methods for mapping the distribution of water tracks in boreal regions and a preliminary analysis of the geotechnical impacts of water track interception on infrastructures. The study area is Goldstream Road in Fairbanks, Alaska. This road experiences high amounts of damage, possibly due to interception of prominent water tracks. To investigate the road damage, the Alaska Department of Transportation has collected geophysical data in 2012. We plan to create a water track distribution map around the Goldstream Road using high-spatial-and-spectral-resolution remote sensing imagery and correlate it with the geophysical data from 2012. We have collected ground data from two water tracks: one in a residence in Fairbanks and the other besides the Goldstream Road. The two tracks vary greatly in size and features. Both water tracks revealed different yet quite promising characteristics. These findings will be used to extract other water tracks from remotely sensed images of the Goldstream Road area. So far, a 2010 SPOT 5 image (2.5m x 2.5 m), an aerial orthophoto (14 cm x 14 cm) and a DEM (57 cm x 57 cm) from September 2014 have been acquired. Normalized Difference Vegetation Index (NDVI) processing was performed on the 2010 SPOT 5 image. A detailed water track database was created and water tracks are being manually digitized from the available imagery and Web Mapping Services (WMS). As a test, using FLIR, handheld

  9. The Influence of Orbital Resonances on the Water Transport to Objects in the Circumprimary Habitable Zone of Binary Star Systems

    Science.gov (United States)

    Bancelin, David; Pilat-Lohinger, Elke; Maindl, Thomas I.; Ragossnig, Florian; Schäfer, Christoph

    2017-06-01

    We investigate the role of secular and mean motion resonances on the water transport from a belt of icy asteroids onto planets or embryos orbiting inside the circumprimary habitable zone (HZ) of a binary star system. In addition, the host-star has an accompanying gas giant planet. For a comparison, we perform two case studies where a secular resonance (SR) is located either inside the HZ close to 1.0 au (causing eccentric motion of a planet or embryos therein) or in the asteroid belt, beyond the snow line. In the latter case, a higher flux of icy objects moving toward the HZ is expected. Collisions between asteroids and objects in the HZ are treated analytically. Our purely dynamical study shows that the SR in the HZ boosts the water transport however, collisions can occur at very high impact speeds. In this paper, we treat for the first time, realistic collisions using a GPU 3D-SPH code to assess the water loss in the projectile. Including the water loss into the dynamical results, we get more realistic values for the water mass fraction of the asteroid during an impact. We highlight that collisions occurring at high velocities greatly reduce the water content of the projectile and thus the amount of water transported to planets or embryos orbiting inside the HZ. Moreover, we discuss other effects that could modify our results, namely the asteroid’s surface rate recession due to ice sublimation and the atmospheric drag contribution on the asteroids’ mass loss.

  10. 49 CFR Appendix to Part 800 - Request to the Secretary of the Department of Transportation To Investigate Certain Aircraft...

    Science.gov (United States)

    2010-10-01

    ... Transportation To Investigate Certain Aircraft Accidents Appendix to Part 800 Transportation Other Regulations... the Department of Transportation To Investigate Certain Aircraft Accidents (a) Acting pursuant to the... Safety Board Act of 1974, and as set forth below to investigate the facts, conditions, and circumstances...

  11. A numerical investigation on multi-phase transport phenomena in a proton exchange membrane fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Le, Anh Dinh; Zhou, Biao [Department of Mechanical, Automotive and Materials Engineering, University of Windsor, 401 Sunset Ave., Windsor, ON (Canada)

    2010-08-15

    In this study, the simulation of a fuel cell stack is performed by applying a general numerical model with VOF method that has been successfully applied to single PEMFC model to investigate the fluid dynamics, mass transport, flooding phenomenon and the effects of liquid water on the stack performance. The performance of three single cells in series connection in the fuel cell stack is examined according to the presence of liquid water in different single cells. The distributions of fluid flow, species concentration and the current density are presented to illustrate the effects of liquid water on the performance of each single cell. The numerical results locate that the low distributions of species in the flooding cell certainly degrade the performance of this cell. Moreover, it can be seen that the performance of the flooding cell will significantly affect the whole stack performance since the values of average current density must be identical in all single cells. (author)

  12. Colloid transport, retention, and remobilization during two-phase flow: Micro-model investigation and modeling

    NARCIS (Netherlands)

    Zhang, Q.

    2013-01-01

    In this study the transport of colloids in a two-phase fluid system is investigated. In particular, the effects on the interface of two immiscible fluids in steady-state and transient circumstances in a micro-porous network are investigated. The experimental setup is designed consisting of micro

  13. Radiotracer method to study the transport of mercury(II)chloride from water to sediment and air

    International Nuclear Information System (INIS)

    Karaca, F.; Aras, N.K.

    2004-01-01

    The fate of dissolved Hg(II) in surface waters is an important component of the Hg cycle. A simple experimental methodology was used to understand and measure the transport of Hg(II) from water to air and sediment. The use of radioactive dissolved Hg tracer for the determination of evasion and deposition is found to be a very useful technique. The evasion of mercury was investigated during a 140-hour period. It was observed that about a quarter of mercury chloride remained in the water phase, the other quarter was emitted via the evasion process and half of it deposited in sediment. (author)

  14. Investigating the Potential of Single-Walled Aluminosilicate Nanotubes in Water Desalination.

    Science.gov (United States)

    Liou, Kai-Hsin; Kang, Dun-Yen; Lin, Li-Chiang

    2017-01-18

    Water shortage has become a critical issue. To facilitate the large-scale deployment of reverse-osmosis water desalination to produce fresh water, discovering novel membranes is essential. Here, we computationally demonstrate the great potential of single-walled aluminosilicate nanotubes (AlSiNTs), materials that can be synthesized through scalable methods, in desalination. State-of-the-art molecular dynamics simulations were employed to investigate the desalination performance and structure-performance relationship of AlSiNTs. Free energy profiles, passage time distribution, and water density map were also analyzed to further understand the dependence of transport properties on diameter and water dynamics in the nanotubes. AlSiNTs with an inner diameter of 0.86 nm were found to fully reject NaCl ions while allowing orders of magnitude higher water fluxes compared to currently available reverse osmosis membranes, providing opportunities in water desalination. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Laboratory investigation of water extraction effects on saltwater wedge displacement

    Directory of Open Access Journals (Sweden)

    S. Noorabadi

    2017-12-01

    Full Text Available There is a close connection between saltwater intrusion into aquifers and groundwater extraction. Freshwater extraction in coastal aquifers is one of the most important reasons for the saltwater intrusion into these aquifers. Condition of extraction system such as well depth, discharge rate, saltwater concentration and etc. could affect this process widely. Thus, investigating different extraction conditions comprises many management advantages.  In the present study, the effects of freshwater extraction on saltwater interface displacement have been investigated in a laboratory box. Three different well depths (H were considered with combinations of 3 different extraction rates (Q and 3 saltwater concentrations (C for detailed investigation of the effects of these factors variations on saltwater displacement. SEAWAT model has been used to simulate all the scenarios to numerically study of the process. The experimental and numerical results showed that when the C and Q rates were small and the well depth was shallow, the saltwater interface wouldn’t reach the extraction well, so the extracted water remained uncontaminated. When the C and Q rates were increased and the well was deepened, the salinity of the extracted water became higher. When the Q and C rates were high enough, in the shallow well depth, the final concentration of the extracted water was low but a huge part of the porous media was contaminated by the saltwater, furthermore when the well was deepened enough, the final concentration of the extracted water was increased but a small part of the porous media was contaminated by the saltwater. Finally, the results showed that when the Q and H rates were high enough, the extraction well behaved like a barrier and didn’t allow the advancing saltwater wedge toe to be intruded beyond the wells.

  16. Transport-limited water splitting at ion-selective interfaces during concentration polarization

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Peder; Bruus, Henrik

    2014-01-01

    We present an analytical model of salt- and water-ion transport across an ion-selective interface based on an assumption of local equilibrium of the water-dissociation reaction. The model yields current-voltage characteristics and curves of water-ion current versus salt-ion current, which are in ...

  17. Measurement of water transport from saturated pumice aggregates to hardening cement paste

    DEFF Research Database (Denmark)

    Lura, Pietro; Bentz, Dale; Lange, David A.

    2006-01-01

    In internal water curing of High Performance Concrete, it is fundamental to know how and when the water contained in the internal curing agent is released into the hydrating cement paste. In this study, X-ray absorption measurements showed that considerable transport of water from saturated pumice...... the crucial factor to avoid self-desiccation shrinkage at early-age....

  18. Whole-tree water transport scales with sapwood capacitance in tropical forest canopy trees.

    Science.gov (United States)

    F.C. Meinzer; S.A. James; G. Goldstein; D. Woodruff

    2003-01-01

    The present study examines the manner in which several whole-tree water transport properties scale with species specific variation in sapwood water storage capacity. The hypothesis that constraints on relationships between sapwood capacitance and other water relations characteristics lead to predictable scaling relationships between intrinsic capacitance and whole-tree...

  19. The impacts of water stress on phloem transport in Douglas-fir trees

    Science.gov (United States)

    David Woodruff

    2014-01-01

    Despite the critical role that phloem plays in a number of plant functional processes and the potential impact of water stress on phloem structural and phloem sap compositional characteristics, little research has been done to examine how water stress influences phloem transport. The objectives of this study were to develop a more accurate understanding of how water...

  20. Experimental and Numerical Investigations of Silver Nanoparticle Transport under Variable Flow and Ionic Strength in Soil.

    Science.gov (United States)

    Makselon, Joanna; Zhou, Dan; Engelhardt, Irina; Jacques, Diederik; Klumpp, Erwin

    2017-02-21

    Unsaturated column experiments were conducted with an undisturbed loamy sand soil to investigate the influence of flow interruption (FI) and ionic strength (IS) on the transport and retention of surfactant-stabilized silver nanoparticles (AgNP) and the results were compared to those obtained under continuous flow conditions. AgNP concentrations for breakthrough curves (BTCs) and retention profiles (RPs) were analyzed by ICP-MS. Experimental results were simulated by the numerical code HP1 (Hydrus-PhreeqC) with the DLVO theory, extended colloid filtration theory and colloid release model. BTCs of AgNP showed a dramatic drop after FI compared to continuous flow conditions. Evaporation increased due to FI, resulting in increased electrical conductivity of the soil solution, which led to a totally reduced mobility of AgNP. A reduction of IS after FI enhanced AgNP mobility slightly. Here the strongly increased Al and Fe concentration in the effluent suggested that soil colloids facilitated the release of AgNP (cotransport). The numerical model reproduced the measured AgNP BTCs and indicated that attachment to the air-water interface (AWI) occurring during FI was the key process for AgNP retention.

  1. Critical review: Radionuclide transport, sediment transport, and water quality mathematical modeling; and radionuclide adsorption/desorption mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Y.; Serne, R.J.; Arnold, E.M.; Cowan, C.E.; Thompson, F.L. [Pacific Northwest Lab., Richland, WA (United States)

    1981-01-01

    This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, {sup 3}H, U, Zn and Zr.

  2. Water sorption and transport in dry crispy bread crust

    NARCIS (Netherlands)

    Meinders, M.B.J.; Nieuwenhuijzen, van N.H.; Tromp, R.H.; Hamer, R.J.; Vliet, van T.

    2010-01-01

    Water sorption and dynamical properties of bread crust have been studied using gravimetric sorption experiments. Water uptake and loss were followed while relative humidity (RH) was stepwise in- or decreased (isotherm experiment) or varied between two adjusted values (oscillatory experiment).

  3. Experimental and modelling investigations of tracer transport in variably saturated agricultural soil of Thailand: Column study

    Directory of Open Access Journals (Sweden)

    Tulaya Masipan

    2016-03-01

    Full Text Available Tracer (Bromide movement through the unsaturated agricultural soil was investigated in soil columns. Two tracer column experiments, with a diameter of 7 cm and a depth of 25 cm, were vertically homogeneous packed with sandy loam and then carried out to investigate bromide (Br− transport under different water contents (at steady flow condition. One soil column (Column 1 represents the unsaturated agricultural soil in dry season (with water content ranging from 0.23 to 0.26 and the other (Column 2 represents the soil in wet season (water content from 0.24 to 0.35. Bromide samples were periodically collected by vacuum tubes inserted at 6.25 cm equally spaced intervals (e.g., 6.25, 12.5, 18.75 and 25 cm along the length of the column and the effluent collected at the end of the column. The observed breakthrough curves (BTCs of bromide in both columns represented a relative smooth and sigmodal curves at different distances (sampling ports. Dispersivity (α, cm for sandy loam at different locations was numerically estimated by curve fitting the experimental data with HYDRUS-1D. The α can be well described by the convection–dispersion equation and these values derived from Column 1 (ranging from 0.37 to 0.98 cm are more than those from Column 2 (0.25–0.59. Moreover, the α in both columns increases with the travel distance due to the scale-dependent effect. Furthermore, the α values were plotted on a log–log scale against travel distances and they yield empirical power law relationships with an excellent correlation (α = 0.102 (L0.697, R2 = 0.999 and α = 0.086 (L0.579, R2 = 0.963 for Column 1 and 2, respectively.

  4. [Investigation of the methods of extension of useful life of nanofiltration membranes in washing water regenerating system].

    Science.gov (United States)

    Shumilina, I V; Krivobok, S M; Maksimov, E D

    2000-01-01

    Transport and selective characteristics of Russian nanofiltration membranes OPMN-K were investigated in order to find approaches to extend useful life of the membranes and, therefore, of the nanofiltration assembly and the washing water regenerating system at large. Hygienic cleansing agents as washing water ingredients pollute but not irreversibly impair the membranes. Flushing of membranes after regeneration of various model detergents was shown to recover the membrane permeability virtually up to original level.

  5. Modelling of the reactive transport of organic pollutants in ground water; Modellierung des reaktiven Transports organischer Schadstoffe im Grundwasser

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, W. [Heidelberg Univ. (Germany). Inst. fuer Umweltphysik

    1999-07-01

    The book describes reactive transport of organic pollutants in ground water and its quantitative monitoring by means of numerical reaction transport models. A brief introduction dealing with the importance of and hazards to ground water and opportunities for making use of ground water models is followed by a more detailed chapter on organic pollutants in ground water. Here the focus is on organochlorine compounds and mineral oil products. Described are propagation mechanisms for these substances in the ground and, especially, their degradability in ground water. A separate chapter is dedicated to possibilities for cleaning up polluted ground water aquifers. The most important decontamination techniques are presented, with special emphasis on in-situ processes with hydraulic components. Moreover, this chapter discusses the self-cleaning capability of aquifers and the benefits of the application of models to ground water cleanup. In the fourth chapter the individual components of reaction transport models are indicated. Here it is, inter alia, differences in the formulation of reaction models as to their complexity, and coupling between suspended matter transport and reaction processes that are dealt with. This chapter ends with a comprehensive survey of literature regarding the application of suspended matter transport models to real ground water accidents. Chapter 5 consists of a description of the capability and principle of function of the reaction transport model TBC (transport biochemism/chemism). This model is used in the two described applications to the reactive transport of organic pollutants in ground water. (orig.) [German] Inhalt des vorliegenden Buches ist die Darstellung des reaktiven Transports organischer Schadstoffe im Grundwasser und dessen quantitative Erfassung mithilfe numerischer Reaktions-Transportmodelle. Auf eine kurze Einleitung zur Bedeutung und Gefaehrdung von Grundwasser und zu den Einsatzmoeglichkeiten von Grundwassermodellen folgt ein

  6. An Assessment of Transport Property Estimation Methods for Ammonia–Water Mixtures and Their Influence on Heat Exchanger Size

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Modi, Anish; Jensen, Jonas Kjær

    2015-01-01

    Transport properties of fluids are indispensable for heat exchanger design. The methods for estimating the transport properties of ammonia–water mixtures are not well established in the literature. The few existent methods are developed from none or limited, sometimes inconsistent experimental...... of ammonia–water mixtures. Firstly, the different methods are introduced and compared at various temperatures and pressures. Secondly, their individual influence on the required heat exchanger size (surface area) is investigated. For this purpose, two case studies related to the use of the Kalina cycle...... the interpolative methods in contrast to the corresponding state methods. Nevertheless, all possible mixture transport property combinations used herein resulted in a heat exchanger size within 4.3 % difference for the flue-gas heat recovery boiler, and within 12.3 % difference for the oil-based boiler....

  7. 33 CFR 336.2 - Transportation of dredged material for the purpose of disposal into ocean waters.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Transportation of dredged material for the purpose of disposal into ocean waters. 336.2 Section 336.2 Navigation and Navigable Waters... WATERS OF THE U.S. AND OCEAN WATERS § 336.2 Transportation of dredged material for the purpose of...

  8. Water vapor and gas transport through PEO PBT block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2002-01-01

    Introduction At the bore well natural gas is saturated with water. Downstream the presence of water may cause: formation of methane hydrates (blocking eventually the pipeline), condensation of water in the pipeline and corrosion effects. A process used for the dehydration of natural gas is glycol

  9. Hygienic investigation of coastal waters of the upper Adriatic Sea.

    Science.gov (United States)

    Möse, J R; Mascher, F; Pichler-Semmelrock, F; Köck, M; Reinthaler, F F

    1990-05-01

    In the course of the bathing season of 1989, investigations of bathing waters were carried out in two-week intervals. From the point of view of public health, the chemical-physical and microbiological results do not suggest objections against bathing at the beach areas investigated (Grado, Lignano). However, these favorable results do not imply intact ecological conditions. National and international standards are designed for humans and allow only very limited conclusions about the living conditions of the marine ecosystem. This also means that ecological investigations are not sufficient to permit conclusions about hygienic conditions. In spite of this seeming contradiction, hygienic and ecological concerns are clearly identical. Hygienic measures must not be limited to local "cosmetic" corrections but must target foremost unfavorable basic conditions.

  10. Numerical and experimental investigation of thermosyphon solar water heater

    International Nuclear Information System (INIS)

    Zelzouli, Khaled; Guizani, Amenallah; Kerkeni, Chakib

    2014-01-01

    Highlights: • We studied a thermosyphon solar water heater composed of high-performance components. • A differential equations solution technique is investigated. • The influences of the collector and storage losses on the system performance were examined. • The storage losses have more influence on the long-term performance. - Abstract: A glassed flat plate collector with selective black chrome coated absorber and a low wall conductance horizontal storage are combined in order to set up a high performance thermosyphon system. Each component is tested separately before testing the complete system in spring days. During the test period, effect of different inlet water temperatures on the collector performance is studied and results have shown that the collector can reach a high efficiency and high outlet water temperature even for elevated inlet water temperatures. Subsequently, long term system performance is estimated by using a developed numerical model. The proposed model, accurate and gave a good agreement with experimental results, allowed to describe the heat transfer in the storage. It has shown also that the long-term performances are strongly influenced by losses from the storage than losses from the collector

  11. Risk assessment of pesticide transport with water erosion: A conceptual model

    Science.gov (United States)

    Yang, Xiaomei; Van Der Zee, Sjoerd E. A. T. M.; Gai, Lingtong; Wesseling, Jan G.; Ritsema, Coen J.; Geissen, Violette

    2017-04-01

    Pesticides are widely used in agriculture, horticulture, and forestry, and pesticide pollution has become an important issue worldwide. Entraining in runoff and being attached to eroded soil particles, posing a risk to water and soil quality and human health. In order to assess the risk of pesticide during water erosion processes, a simple integrative model of pesticide transport by runoff and erosion was developed. Taking soil hydrological and pesticide behaviour into account, such as water infiltration, erosion, runoff, and pesticide transport and degradation in soil, the conceptual framework was based on the known assumptions such as the convection-dispersion equation and lognormal distributions of soil properties associated with transport, sorption, degradation, and erosion. A sensitivity analysis was conducted and the results indicated that the total amount of pesticide related to soil eroded by water washing increased with slope gradient, rainfall intensity, and water field capacity of the soil. The mass of transported pesticide decreased as the micro-topography of the soil surface became obviously and the time from pesticide sprayed to erosion occurring associated with pesticide degradation negatively influenced the total amount of transported pesticide. The mechanisms involved in pesticide transport, such as runoff, infiltration, soil erosion, and pesticide transport and decay in the topsoil, thus can be well accounted for pesticide risk assessment especially in the region with intensive pesticide use and soil water erosion events.

  12. Anatomical features associated with water transport in imperforate tracheary elements of vessel-bearing angiosperms

    Science.gov (United States)

    Sano, Yuzou; Morris, Hugh; Shimada, Hiroshi; Ronse De Craene, Louis P.; Jansen, Steven

    2011-01-01

    Background and Aims Imperforate tracheary elements (ITEs) in wood of vessel-bearing angiosperms may or may not transport water. Despite the significance of hydraulic transport for defining ITE types, the combination of cell structure with water transport visualization in planta has received little attention. This study provides a quantitative analysis of structural features associated with the conductive vs. non-conductive nature of ITEs. Methods Visualization of water transport was studied in 15 angiosperm species by dye injection and cryo-scanning electron microscopy. Structural features of ITEs were examined using light and electron microscopy. Key Results ITEs connected to each other by pit pairs with complete pit membranes contributed to water transport, while cells showing pit membranes with perforations up to 2 µm were hydraulically not functional. A close relationship was found between pit diameter and pit density, with both characters significantly higher in conductive than in non-conductive cells. In species with both conductive and non-conductive ITEs, a larger diameter was characteristic of the conductive cells. Water transport showed no apparent relationship with the length of ITEs and vessel grouping. Conclusions The structure and density of pits between ITEs represent the main anatomical characters determining water transport. The pit membrane structure of ITEs provides a reliable, but practically challenging, criterion to determine their conductive status. It is suggested that the term tracheids should strictly be used for conductive ITEs, while fibre-tracheids and libriform fibres are non-conductive. PMID:21385773

  13. Water as a transport medium for waste out of towns

    DEFF Research Database (Denmark)

    Harremoës, P.

    1999-01-01

    The historical background for centralised water management in the cities of the developed world is outlined in order to give the rationale for the technical solutions we have inherited from the last century. The key element is maintaining the hygienic conditions in the cities. The success is illu...... water use, because water is not lost, but polluted, which can be abated. Water can be re-routed and recycled. There are many attractive local solutions for better handling of urban water. (C) 1999 IAWQ Published by Elsevier Science Ltd.-All rights reserved....

  14. Effect of gravity on colloid transport through water-saturated columns packed with glass beads: modeling and experiments.

    Science.gov (United States)

    Chrysikopoulos, Constantinos V; Syngouna, Vasiliki I

    2014-06-17

    The role of gravitational force on colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q = 1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one-dimensional, colloid transport model. The effect of gravity is incorporated in the mathematical model by combining the interstitial velocity (advection) with the settling velocity (gravity effect). The results revealed that flow direction influences colloid transport in porous media. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for colloid deposition.

  15. Copper distribution in water-dispersible colloids of swine manure and its transport through quartz sand.

    Science.gov (United States)

    Bao, Qibei; Lin, Qi; Tian, Guangming; Wang, Guihao; Yu, Jian; Peng, Guiqun

    2011-02-28

    To demonstrate the potential risks associated with the application of solid agricultural wastes, we investigated Cu distribution in water-dispersible colloids derived from swine manure and its transport through quartz sand. Samples were sequentially centrifuged to obtain five colloid suspensions (colloid subsamples (1-10, 0.45-1, 0.2-0.45, and 0.02-0.2 μm). We observed that 2% of Cu in the swine manure was found in the 0.02-10 μm colloid fractions, while 18% was observed in the colloid suspension. The highest accumulation of Cu was found in the 0.02-0.2 μm fraction of colloids, in which organic carbon was the major component. The Cu in the 1-10 μm colloid fraction existed in both inorganic compounds and organic associations, whereas it mainly existed as organic complexes in colloids colloids (1-10 μm) of swine manure were partially filtered out as they passed through the sand particles, and fine colloids facilitated the transport of Cu. The formation of organic complexes was hypothesized to enhance the mobility of Cu. Further research is needed to incorporate our experimental findings into a realistic model of particle mobilization and transport through soil or groundwater aquifers. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Field-scale water flow and solute transport : SWAP model concepts, parameter estimation and case studies = [Waterstroming en transport van opgeloste stoffen op veldschaal

    NARCIS (Netherlands)

    Dam, van J.C.

    2000-01-01

    Water flow and solute transport in top soils are important elements in many environmental studies. The agro- and ecohydrological model SWAP (Soil-Water-Plant-Atmosphere) has been developed to simulate simultaneously water flow, solute transport, heat flow and crop growth at field scale

  17. Water, solute and heat transport in the soil: the Australian connection

    Science.gov (United States)

    Knight, John

    2016-04-01

    The interest of Peter Raats in water, solute and heat transport in the soil has led to scientific and/or personal interactions with several Australian scientists such as John Philip, David Smiles, Greg Davis and John Knight. Along with John Philip and Robin Wooding, Peter was an early user of the Gardner (1958) linearised model of soil water flow, which brought him into competition with John Philip. I will discuss some of Peter's solutions relevant to infiltration from line and point sources, cavities and basins. A visit to Canberra, Australia in the early 1980s led to joint work on soil water flow, and on combined water and solute movement with David Smiles and others. In 1983 Peter was on the PhD committee for Greg Davis at the University of Wollongong, and some of the methods in his thesis 'Mathematical modelling of rate-limiting mechanisms of pyritic oxidation in overburden dumps' were later used by Peter's student Sjoerd van der Zee. David Smiles and Peter wrote a survey article 'Hydrology of swelling clay soils' in 2005. In the last decade Peter has been investigating the history of groundwater and vadose zone hydrology, and recently he and I have been bringing to light the largely forgotten work of Lewis Fry Richardson on finite difference solution of the heat equation, drainage theory, soil physics, and the soil-plant-atmosphere continuum.

  18. Investigation on flow stability of supercritical water cooled systems

    International Nuclear Information System (INIS)

    Cheng, X.; Kuang, B.

    2006-01-01

    Research activities are ongoing worldwide to develop nuclear power plants with supercritical water cooled reactor (SCWR) with the purpose to achieve a high thermal efficiency and to improve their economical competitiveness. However, the strong variation of the thermal-physical properties of water in the vicinity of the pseudo-critical line results in challenging tasks in various fields, e.g. thermal-hydraulic design of a SCWR. One of the challenging tasks is to understand and to predict the dynamic behavior of supercritical water cooled systems. Although many thermal-hydraulic research activities were carried out worldwide in the past as well as in the near present, studies on dynamic behavior and flow stability of SC water cooled systems are scare. Due to the strong density variation, flow stability is expected to be one of the key items which need to be taken into account in the design of a SCWR. In the present work, the dynamic behavior and flow stability of SC water cooled systems are investigated using both numerical and theoretical approaches. For this purpose a new computer code SASC was developed, which can be applied to analysis the dynamic behavior of systems cooled by supercritical fluids. In addition, based on the assumptions of a simplified system, a theoretical model was derived for the prediction of the onset of flow instability. A comparison was made between the results obtained using the theoretical model and those from the SASC code. A good agreement was achieved. This gives the first evidence of the reliability of both the SASC code and the theoretical model

  19. Macroscopic analysis of characteristic water transport phenomena in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hye-Mi [Graduate School, Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea); Lee, Kwan-Soo; Um, Sukkee [School of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea)

    2008-04-15

    Comprehensive analytical and numerical analyses were performed, focusing on anode water loss, cathode flooding, and water equilibrium for polymer electrolyte fuel cells. General features of water transport as a function of membrane thickness and current density were presented to illustrate the net effect of back-diffusion of water from the cathode to anode over a polymer electrolyte fuel cell domain. First, two-dimensional numerical simulation were performed, showing that the difference in molar concentration of water at the channel outlet is widened as the operating current density increases with a thin membrane (Nafion {sup registered} 111), which was verified by Dong et al. [Distributed performance of polymer electrolyte fuel cells under low-humidity conditions. J Electrochem Soc 2005; 152: A2114-22]. Then, analytical solutions were compared with computational results in predicting those characteristics of water transport phenomena. It was theoretically estimated that the high pressure operation of fuel cells expedites water condensing and results in shorter anode water loss and cathode flooding locations. In this study, it was also found that a thin membrane (Nafion {sup registered} 111) facilitates water transport in the through-membrane direction and therefore water concentration at the anode and cathode channel outlets reaches an equilibrium state particularly at low operating current densities. Moreover, the difference in the anode water concentration between Nafion {sup registered} 111 and Nafion {sup registered} 115 membranes becomes intensified in the in-plane direction under the same water production condition, while the cathode water concentration profiles remains almost same. (author)

  20. Hydrology in Lichens: How Biological Architecture is Used to Regulate Water Access to Support Drought Resilience and Nutrient Transport

    Science.gov (United States)

    Ten Veldhuis, M. C.; Dismukes, G. C.; Ananyev, G.

    2017-12-01

    Lichens are Nature's masters at controlling water and air flux within a symbiotic organism comprised of an algal photobiont and its fungal host. Here we investigated the equilibrium partitioning and kinetic transport of water between the symbionts in the lichen flavoparmelia species. Lichens have developed a unique strategy to recover after deep dehydration, that otherwise would kill the majority of free living phototrophs. By measuring both kinetics of water content and chlorophyll fluorescence emission (indicative of algal charge separation and water oxidation) during dehydration, we identified 3 distinct temporal stages and mapped these to physical zones by confocal microscopy using a combination of hydro-philic/-phobic dyes. Below a critical level of water content, controlled by the greater hydrophilicity of fungal tissues, algal photosynthesis rapidly turns off. We show that the distinct stages in dehydration mirror the 3D architecture of lichen tissue (the thallus). We provide evidence that control of water distribution is achieved by capillary forces within ordered zones of physical space possessing different hydro-phobic/-philic characteristics. This strategy ensures that photosynthetic capacity is protected from and can quickly recover after desiccation. The fungal host controls the onset and extent of photosynthesis in the enslaved alga, presumably to ensure transport of algal derived sugars and oxygen (O2) to the fungal host only when sufficient water exists for transport. Lichen architecture provides Nature's solution to gas-water transport that is self-regulated by humidity. It offers novel lessons for designing practical devices such as fuel cell membranes and dialysis membranes. Supported by the US Dept of Energy, Basic Energy Sciences, Physical Biosciences Division.

  1. Antarctic circumpolar transport and the southern mode: a model investigation of interannual to decadal timescales

    Directory of Open Access Journals (Sweden)

    C. W. Hughes

    2014-04-01

    Full Text Available It is well-established that, at periods shorter than a year, variations in Antarctic circumpolar transport are reflected in a barotropic mode, known as the southern mode, in which sea level and bottom pressure varies coherently around Antarctica. Here, we use two multidecadal ocean model runs to investigate the behaviour of the southern mode at timescales on which density changes become important, leading to a baroclinic component to the adjustment. We find that the concept of a southern mode in bottom pressure remains valid, and remains a direct measure of the circumpolar transport, with changes at the northern boundary playing only a small role even on decadal timescales. However, at periods longer than about 5 years, density changes start to play a role, leading to a surface intensification of the vertical profile of the transport. We also find that barotropic currents on the continental slope account for a significant fraction of the variability, and produce surface intensification in the meridional-integral flow. Circumpolar sea level and transport are related at all investigated timescales. However, the role of density variations results in a ratio of sea level change to transport which becomes larger at longer timescales. This means that any long-term transport monitoring strategy based on present measurement systems must involve multiplying the observed quantity by a factor which depends on frequency.

  2. Water characteristics and transport of the Antarctic circumpolar current in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Mathew, B.

    Geostrophic velocities are computed across meridians 37 degrees E and 105 degrees E using hydrographic data. The estimated mass transport is represented on a temperature - salinity diagram. The characteristics of the water within the Antarctic...

  3. On water transport in polymer electrolyte membranes during the passage of current

    DEFF Research Database (Denmark)

    Berning, Torsten

    2011-01-01

    This article discusses an approach to model the water transport in the membranes of PEM fuel cells during operation. Starting from a frequently utilized equation the various transport mechanisms are analyzed in detail. It is shown that the commonly used approach to simply balance the electro......-osmotic drag (EOD) with counter diffusion and/or hydraulic permeation is flawed, and that any net transport of water through the membrane is caused by diffusion. Depending on the effective drag the cathode side of the membrane may experience a lower hydration than the anode side. The effect of a water......-uptake layer on the net water transport will also be pictured. Finally, the effect of EOD is visualized using “Newton’s cradle”....

  4. Chapter II.C Transport of Radionuclides through Soil and Ground Water; FINAL

    International Nuclear Information System (INIS)

    Corey, J.C.

    1980-01-01

    The purpose of this report is to provide a clearer perspective of the impact of radionuclides in soil and groundwater, particularly for those not well-versed in soil science, hydrology, and geology. Through nuclear waste disposal or accidents, radionuclides come in contact with soil and groundwater. Man is exposed to radiation as a result of movement (or transport) of the radionuclides into his environment. Water is the principal carrier that induces transport, but chemical characteristics of soil inhibit the transport

  5. Transportation of spent fuel from light water reactors

    International Nuclear Information System (INIS)

    Bernard, H.

    1993-01-01

    The French 'Compagnie Generale des Matieres Nucleaires' - COGEMA - is involved in the whole nuclear fuel cycle about 20 years. Among the different parts of the cycle, the Transport of Radioactive Materials, acting as a link between the differents plants has a great importance. As nuclear material transportation is the only fuel cycle step to be performed on public grounds, the industrial task has to be performed with the utmost stringent safety criteria. COGEMA and associates is now operating a fully mature commercial activity, with some 300 spent fuel shipments per year from its reprocessing customer's reactors to the LA HAGUE plant, either by rail, road or sea. The paper will review the organization of COGEMA transportation business, the level of technology with an update of the casks used for spent fuel, and the operational experience, with a particular view of the maintenance policy. (author)

  6. Models for the transport of low energy electrons in water and the yield of hydrated electrons at early times

    International Nuclear Information System (INIS)

    Brenner, D.J.; Miller, J.H.; Ritchie, R.H.; Bichsel, H.

    1985-01-01

    An insulator model with four experimental energy bands was used to fit the optical properties of liquid water and to extend these data to non-zero momentum transfer. Inelastic mean free paths derived from this dielectric response function provided the basic information necessary to degrade high energy electrons to the subexcitation energy domain. Two approaches for the transport of subexcitation electrons were investigated. (i) Gas phase cross sections were used to degrade subexcitation electrons to thermal energy and the thermalization lengths were scaled to unit density. (ii) Thermalization lengths were estimated by age-diffusion theory with a stopping power deduced from the data on liquid water and transport cross sections derived from elastic scattering in water vapor. Theoretical ranges were compared to recent experimental results. A stochastic model was used to calculate the rapid diffusion and reaction of hydrated electrons with other radiolysis products. The sensitivity of the calculated yields to the model assumptions and comparison with experimental data are discussed

  7. Transport processes investigation: A necessary first step in site scale characterization plans

    International Nuclear Information System (INIS)

    Roepke, C.; Glass, R.J.; Brainard, J.; Mann, M.; Kriel, K.; Holt, R.; Schwing, J.

    1995-01-01

    We propose an approach, which we call the Transport Processes Investigation or TPI, to identify and verify site-scale transport processes and their controls. The TPI aids in the formulation of an accurate conceptual model of flow and transport, an essential first step in the development of a cost effective site characterization strategy. The TPI is demonstrated in the highly complex vadose zone of glacial tills that underlie the Fernald Environmental Remediation Project (FEMP) in Fernald, Ohio. As a result of the TPI, we identify and verify the pertinent flow processes and their controls, such as extensive macropore and fracture flow through layered clays, which must be included in an accurate conceptual model of site-scale contaminant transport. We are able to conclude that the classical modeling and sampling methods employed in some site characterization programs will be insufficient to characterize contaminant concentrations or distributions at contaminated or hazardous waste facilities sited in such media

  8. Water transport through graphene oxide membranes: the roles of driving forces.

    Science.gov (United States)

    Chong, J Y; Wang, B; Li, K

    2018-02-21

    Graphene oxide (GO) membranes have shown excellent selectivities in nanofiltration and pervaporation. However, the water transport mechanisms in the unique membrane laminar structure are still not well understood, especially in pervaporation which involves selective permeation and evaporation. Herein, water transport in GO membranes was tested under two different modes: pressure-driven permeation and pervaporation. The pure water flux was found to be 1-2 orders of magnitude higher in pervaporation due to the large capillary pressure induced by evaporation. The water flux in pervaporation was suggested to be limited by evaporation at room temperature but surface diffusion at high temperature.

  9. Heavy metal transport processes in surface water and groundwater. Geochemical and isotopic aspects

    International Nuclear Information System (INIS)

    Tricca, A.

    1997-01-01

    This work deals with the transport mechanisms of trace elements in natural aquatic systems. The experimental field is situated in the Upper Rhine Rift Valley because of the density and variety of its hydrological net. This study focused on three aspects: the isotopic tracing with Sr, Nd and O allowed to characterize the hydro-system. The 87 Sr/ 86 Sr and 143 Nd/ 144 Nd ratios show that the system is controlled by two natural end members a carbonate and a silicate one and a third end member of anthropogenic origin. The isotopic data allowed also to investigate the exchange processes between the dissolved and the particulate phases of the water samples. Because of their use in the industry and their very low concentrations in natural media, the Rare Earth Elements (REE) are very good tracers of anthropogenic contamination. Furthermore, due to their similar chemical properties with the actinides,they constitute excellent analogues to investigate the behaviour of fission products in the nature. In this study we determined the distribution of the REE within a river between the dissolved, the colloidal and the particulate phases. Among the REE of the suspended load, we distinguished between the exchangeable and the residual REE by means OF IN HCl leading experiments. The third topic is the investigation of uranium series disequilibrium using α-Spectrometry. The determination of ratios 234 U/ 238 U as well as of the activities short-lived radionuclides like 222 Rn, 224 Ra, 226 Ra, 228 Ra, 210 Po and 210 Pb have been performed. Their activities are controlled by chemical and physical parameters and depend also on the lithology of the source area. The combination of the three aspects provided relevant informations about the exchanges between the different water masses, about the transport mechanisms of the REE. Furthermore, the uranium series disequilibrium provided informations about the geochemical processes at a micro-scale. (author)

  10. Transport of tylosin and tylosin-resistance genes in subsurface drainage water from manured fields

    Science.gov (United States)

    Animal agriculture appears to contribute to the spread of antibiotic resistance genes, but few studies have quantified gene transport in agricultural fields. The transport of tylosin, tylosin-resistance genes (erm B, F, A) and tylosin-resistant Enterococcus were measured in tile drainage water from ...

  11. Development of Telematics and its Application in Water Transport

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2003-01-01

    Full Text Available Significant increase in traffic demand at the end of the 2nd century and the increasing anthropogenic environmental pollutionhave resulted in the need to introduce the telematics-supportedintelligent transport systems in all the traffic branches.The work presents the development and the basic characteristicsof transport systems managed by information and communicationtechnologies. Also, the possible development and advantagesof implementing telematics in the traffic along theriver of Danube through Austria, as well as monitoring sea-goingships and containers in intennodal traffic.

  12. Traffic and transport technology-road, railway, and water-borne transportation

    Science.gov (United States)

    1990-01-01

    This is "Part 2: Case Studies - Chapter 9" of the book, "The Japanese Experience in Technology", and includes the following subsections: Modernization and the railway; The transportation network; Issues in railway policy; Original design and producti...

  13. Investigating the environmental transport of human pharmaceuticals to streams in the United Kingdom

    Energy Technology Data Exchange (ETDEWEB)

    Ashton, D.; Hilton, M.; Thomas, K.V

    2004-10-15

    The occurrence of 12 selected pharmaceutical compounds and pharmaceutical compound metabolites in sewage treatment works (STW) effluents and surface waters was investigated. The substances selected for the monitoring programme were identified by a risk ranking procedure to identify those substances with the greatest potential to pose a risk to the aquatic environment. STW final effluent and surface water samples were collected from Corby, Great Billing, East Hyde, Harpenden and Ryemeads STWs. Ten of the 12 pharmaceutical compounds were detected in the STW effluent samples: propranolol (100%, median=76 ng/l), diclofenac (86%, median=424 ng/l), ibuprofen (84%, median=3086 ng/l), mefenamic acid (81%, median=133 ng/l), dextropropoxyphene (74%, median=195 ng/l), trimethoprim (65%, 70 ng/l), erythromycin (44%, <10 ng/l), acetyl-sulfamethoxazole (33%, median=<50 ng/l), sulfamethoxazole (9%, median=<50 ng/l), tamoxifen (4%, median=<10 ng/l). In the corresponding receiving streams, fewer compounds and lower concentrations were found: propranolol (87%, median=29 ng/l), ibuprofen (69%, median=826 ng/l), mefenamic acid (60%, median=62 ng/l), dextropropoxyphene (53%, median=58 ng/l), diclofenac (47%, median=<20 ng/l), erythromycin (38%, median=<10 ng/l), trimethoprim (38%, median=<10 ng/l), acetyl sulfamethoxazole (38%, median=<50 ng/l). Four human pharmaceutical compounds were detected in samples upstream of the STWs sampled: ibuprofen (57%, median=181 ng/l), trimethoprim (36%, median <10 ng/l), erythromycin (17%, median=<10 ng/l), propranolol (14%, median=<10 ng/l), suggesting that longer range stream transport of some compounds is possible. The particular STW that was sampled and the month that it was sampled significantly influenced the measured concentrations of several, but not all, substances. There was no significant relationship between usage data and the overall frequency with which different substances were detected. There was however, some evidence to suggest that

  14. Investigating the environmental transport of human pharmaceuticals to streams in the United Kingdom

    International Nuclear Information System (INIS)

    Ashton, D.; Hilton, M.; Thomas, K.V.

    2004-01-01

    The occurrence of 12 selected pharmaceutical compounds and pharmaceutical compound metabolites in sewage treatment works (STW) effluents and surface waters was investigated. The substances selected for the monitoring programme were identified by a risk ranking procedure to identify those substances with the greatest potential to pose a risk to the aquatic environment. STW final effluent and surface water samples were collected from Corby, Great Billing, East Hyde, Harpenden and Ryemeads STWs. Ten of the 12 pharmaceutical compounds were detected in the STW effluent samples: propranolol (100%, median=76 ng/l), diclofenac (86%, median=424 ng/l), ibuprofen (84%, median=3086 ng/l), mefenamic acid (81%, median=133 ng/l), dextropropoxyphene (74%, median=195 ng/l), trimethoprim (65%, 70 ng/l), erythromycin (44%, <10 ng/l), acetyl-sulfamethoxazole (33%, median=<50 ng/l), sulfamethoxazole (9%, median=<50 ng/l), tamoxifen (4%, median=<10 ng/l). In the corresponding receiving streams, fewer compounds and lower concentrations were found: propranolol (87%, median=29 ng/l), ibuprofen (69%, median=826 ng/l), mefenamic acid (60%, median=62 ng/l), dextropropoxyphene (53%, median=58 ng/l), diclofenac (47%, median=<20 ng/l), erythromycin (38%, median=<10 ng/l), trimethoprim (38%, median=<10 ng/l), acetyl sulfamethoxazole (38%, median=<50 ng/l). Four human pharmaceutical compounds were detected in samples upstream of the STWs sampled: ibuprofen (57%, median=181 ng/l), trimethoprim (36%, median <10 ng/l), erythromycin (17%, median=<10 ng/l), propranolol (14%, median=<10 ng/l), suggesting that longer range stream transport of some compounds is possible. The particular STW that was sampled and the month that it was sampled significantly influenced the measured concentrations of several, but not all, substances. There was no significant relationship between usage data and the overall frequency with which different substances were detected. There was however, some evidence to suggest that

  15. Evaluating the costs of desalination and water transport

    NARCIS (Netherlands)

    Zhou, Y.; Tol, R.S.J.

    2005-01-01

    Many regions of the world are facing formidable freshwater scarcity. Although there is substantial scope for economizing on the consumption of water without affecting its service level, the main response to water scarcity has been to increase the supply. To a large extent, this is done by

  16. Simulation of Water Transport through a Lipid Membrane

    NARCIS (Netherlands)

    Marrink, Siewert-Jan; Berendsen, Herman J.C.

    1994-01-01

    To obtain insight in the process of water permeation through a lipid membrane, we performed molecular dynamics simulations on a phospholipid (DPPC)/water system with atomic detail. Since the actual process of permeation is too slow to be studied directly, we deduced the permeation rate indirectly

  17. Probing water structure and transport in proton exchange membranes

    NARCIS (Netherlands)

    Ling, X.

    2018-01-01

    Proton exchange membrane fuel cells (PEMFCs) have attracted tremendous attention as alternative energy sources because of their high energy density and practically zero greenhouse gas emission - water is their only direct by-product. Critical to the function of PEMFCs is fast proton and water

  18. Water as a transport medium for waste out of towns

    DEFF Research Database (Denmark)

    Harremoës, P.

    1999-01-01

    is illustrated by the absence of water-borne diseases in the modem developed city. A new paradigm is introduced based on added concern for the use of resources, pollution of the environment and the concern for the welfare of the coming generations. The water resource is not the unsustainable aspect of urban...

  19. Characterizing the transplanar and in-plane water transport properties of fabrics under different sweat rate: Forced Flow Water Transport Tester.

    Science.gov (United States)

    Tang, K P M; Chau, K H; Kan, C W; Fan, J T

    2015-11-23

    The water absorption and transport properties of fabrics are critical to wear comfort, especially for sportswear and protective clothing. A new testing apparatus, namely Forced Flow Water Transport Tester (FFWTT), was developed for characterizing the transplanar and in-plane wicking properties of fabrics based on gravimetric and image analysis technique. The uniqueness of this instrument is that the rate of water supply is adjustable to simulate varying sweat rates with reference to the specific end-use conditions ranging from sitting, walking, running to other strenuous activities. This instrument is versatile in terms of the types of fabrics that can be tested. Twenty four types of fabrics with varying constructions and surface finishes were tested. The results showed that FFWTT was highly sensitive and reproducible in differentiating these fabrics and it suggests that water absorption and transport properties of fabrics are sweat rate-dependent. Additionally, two graphic methods were proposed to map the direction of liquid transport and its relation to skin wetness, which provides easy and direct comparison among different fabrics. Correlation analysis showed that FFWTT results have strong correlation with subjective wetness sensation, implying validity and usefulness of the instrument.

  20. Update report on fracture flow in saturated tuff: Dynamic transport task for the Nevada Nuclear Waste Investigations

    International Nuclear Information System (INIS)

    Janecky, D.R.; Rundberg, R.S.; Ott, M.; Mitchell, A.

    1990-11-01

    This report summarizes the results of continuing experiments on the behavior of tracers during fracture flow in saturated, welded tuff. These experiments were completed during the past year as part of the Dynamic Transport Task of geochemical investigations for the Yucca Mountain Project sponsored by the US Department of Energy. These experiments are designed to investigate the effects of fluid movement in fractures when coupled with matrix diffusion and sorption but isolated from the effects of capillary suction and two-phase flow characteristic of unsaturated conditions. The experiments reported here are continuations of experimental efforts reported previously. The behavior of three tracers [HTO (tritiated water), TcO 4 - (pertechnetate), and sulforhodamine B dye] have been investigated during flow through a saturated column of densely welded tuff from the Topopah Spring Member of the Paintbrush Tuff, Yucca Mountain, Nye County, southern Nevada. 31 refs., 26 figs., 2 tabs

  1. Investigating transport capacity equations in sediment yield modelling for the Cariri semi-arid region of Paraiba-PB/Brazil

    Directory of Open Access Journals (Sweden)

    E. E. De Figueiredo

    2015-03-01

    Full Text Available In the semi arid Cariri region of the state of Paraiba, Brazil, runoff is of the Hortonian type generated by excess of rainfall over infiltration capacity, and soil erosion is governed by rainfall intensity and sediment size. However, the governing sediment transport mechanism is not well understood. Sediment transport generally depends on the load of sediment provided by soil erosion and on the transport capacity of the flow. The latter is mainly governed by mechanisms such as water shear stress, or stream power. Accordingly, the load of sediment transported by the flow may vary depending on the mechanism involved in the equation of estimation. Investigation of the sediment transport capacity of the flow via a distributed physically-based model is an important and necessary task, but quite rare in semi-arid climates, and particularly in the Cariri region of the state of Paraíba/Brazil. In this study, the equations of Yalin, Engelund & Hansen, Laursen, DuBoys and Bagnold have been coupled with the MOSEE distributed physically based model aiming at identifying the mechanisms leading to the best model simulations when compared with data observed at various basin scales and land uses in the study region. The results obtained with the investigated methods were quite similar and satisfactory suggesting the feasibility of the mechanisms involved, but the observed values were better represented with Bagnold’s equation, which is physically grounded on the stream power, and we recommend it for simulations of similar climate, runoff generation mechanisms and sediment characteristics as in the study region.

  2. Transport modelling in coastal waters using stochastic differential equations

    NARCIS (Netherlands)

    Charles, W.M.

    2007-01-01

    In this thesis, the particle model that takes into account the short term correlation behaviour of pollutants dispersion has been developed. An efficient particle model for sediment transport has been developed. We have modified the existing particle model by adding extra equations for the

  3. Molecular Dynamics of Equilibrium and Pressure-Driven Transport Properties of Water through LTA-Type Zeolites

    KAUST Repository

    Turgman-Cohen, Salomon

    2013-10-08

    We consider an atomistic model to investigate the flux of water through thin Linde type A (LTA) zeolite membranes with differing surface chemistries. Using molecular dynamics, we have studied the flow of water under hydrostatic pressure through a fully hydrated LTA zeolite film (∼2.5 nm thick) capped with hydrophilic and hydrophobic moieties. Pressure drops in the 50-400 MPa range were applied across the membrane, and the flux of water was monitored for at least 15 ns of simulation time. For hydrophilic membranes, water molecules adsorb at the zeolite surface, creating a highly structured fluid layer. For hydrophobic membranes, a depletion of water molecules occurs near the water/zeolite interface. For both types of membranes, the water structure is independent of the pressure drop established in the system and the flux through the membranes is lower than that observed for the bulk zeolitic material; the latter allows an estimation of surface barrier effects to pressure-driven water transport. Mechanistically, it is observed that (i) bottlenecks form at the windows of the zeolite structure, preventing the free flow of water through the porous membrane, (ii) water molecules do not move through a cage in a single-file fashion but rather exhibit a broad range of residence times and pronounced mixing, and (iii) a periodic buildup of a pressure difference between inlet and outlet cages takes place which leads to the preferential flow of water molecules toward the low-pressure cages. © 2013 American Chemical Society.

  4. Molecular dynamics of equilibrium and pressure-driven transport properties of water through LTA-type zeolites.

    Science.gov (United States)

    Turgman-Cohen, Salomon; Araque, Juan C; Hoek, Eric M V; Escobedo, Fernando A

    2013-10-08

    We consider an atomistic model to investigate the flux of water through thin Linde type A (LTA) zeolite membranes with differing surface chemistries. Using molecular dynamics, we have studied the flow of water under hydrostatic pressure through a fully hydrated LTA zeolite film (~2.5 nm thick) capped with hydrophilic and hydrophobic moieties. Pressure drops in the 50-400 MPa range were applied across the membrane, and the flux of water was monitored for at least 15 ns of simulation time. For hydrophilic membranes, water molecules adsorb at the zeolite surface, creating a highly structured fluid layer. For hydrophobic membranes, a depletion of water molecules occurs near the water/zeolite interface. For both types of membranes, the water structure is independent of the pressure drop established in the system and the flux through the membranes is lower than that observed for the bulk zeolitic material; the latter allows an estimation of surface barrier effects to pressure-driven water transport. Mechanistically, it is observed that (i) bottlenecks form at the windows of the zeolite structure, preventing the free flow of water through the porous membrane, (ii) water molecules do not move through a cage in a single-file fashion but rather exhibit a broad range of residence times and pronounced mixing, and (iii) a periodic buildup of a pressure difference between inlet and outlet cages takes place which leads to the preferential flow of water molecules toward the low-pressure cages.

  5. Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Wenbin [General Motors LLC, Pontiac, MI (United States)

    2014-08-29

    This report documents the work performed by General Motors (GM) under the Cooperative agreement No. DE-EE0000470, “Investigation of Micro- and Macro-Scale Transport Processes for Improved Fuel Cell Performance,” in collaboration with the Penn State University (PSU), University of Tennessee Knoxville (UTK), Rochester Institute of Technology (RIT), and University of Rochester (UR) via subcontracts. The overall objectives of the project are to investigate and synthesize fundamental understanding of transport phenomena at both the macro- and micro-scales for the development of a down-the-channel model that accounts for all transport domains in a broad operating space. GM as a prime contractor focused on cell level experiments and modeling, and the Universities as subcontractors worked toward fundamental understanding of each component and associated interface.

  6. Dynamics of the water circulations in the southern South China Sea and its seasonal transports

    DEFF Research Database (Denmark)

    Daryabor, Farshid; Ooi, See Hai Ooi; Samah, Azizan Abu

    2016-01-01

    circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China......A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re......-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast...

  7. A reactive transport investigation of a seawater intrusion experiment in a shallow aquifer, Skansehage Denmark

    DEFF Research Database (Denmark)

    Christensen, Flemming Damgaard; Engesgaard, Peter Knudegaard; Kipp, K.L.

    2001-01-01

    Previous investigations on seawater intrusion have mainly focused on either the physical density flow system with transport of a single non-reactive species or focused on the geochemical aspects neglecting density effects. This study focuses on both the geochemical and physical aspects of seawate...

  8. A reactive transport investigation of a seawater intrusion experiment in a shallow aquifer, Skansehage Denmark

    DEFF Research Database (Denmark)

    Christensen, Flemming Damgaard; Engesgaard, Peter Knudegaard; Kipp, K.L.

    2001-01-01

    Previous investigations on seawater intrusion have mainly focused on either the physical density flow system with transport of a single non-reactive species or focused on the geochemical aspects neglecting density effects. This study focuses on both the geochemical and physical aspects of seawater...

  9. Chemical mass transport between fluid fine tailings and the overlying water cover of an oil sands end pit lake

    Science.gov (United States)

    Dompierre, Kathryn A.; Barbour, S. Lee; North, Rebecca L.; Carey, Sean K.; Lindsay, Matthew B. J.

    2017-06-01

    Fluid fine tailings (FFT) are a principal by-product of the bitumen extraction process at oil sands mines. Base Mine Lake (BML)—the first full-scale demonstration oil sands end pit lake (EPL)—contains approximately 1.9 × 108 m3 of FFT stored under a water cover within a decommissioned mine pit. Chemical mass transfer from the FFT to the water cover can occur via two key processes: (1) advection-dispersion driven by tailings settlement; and (2) FFT disturbance due to fluid movement in the water cover. Dissolved chloride (Cl) was used to evaluate the water cover mass balance and to track mass transport within the underlying FFT based on field sampling and numerical modeling. Results indicated that FFT was the dominant Cl source to the water cover and that the FFT is exhibiting a transient advection-dispersion mass transport regime with intermittent disturbance near the FFT-water interface. The advective pore water flux was estimated by the mass balance to be 0.002 m3 m-2 d-1, which represents 0.73 m of FFT settlement per year. However, the FFT pore water Cl concentrations and corresponding mass transport simulations indicated that advection rates and disturbance depths vary between sample locations. The disturbance depth was estimated to vary with location between 0.75 and 0.95 m. This investigation provides valuable insight for assessing the geochemical evolution of the water cover and performance of EPLs as an oil sands reclamation strategy.

  10. Experimental investigation and CFD simulation of horizontal air/water slug flow

    International Nuclear Information System (INIS)

    Vallee, C.; Hoehne, T.; Prasser, H.M.; Suehnel, T.

    2006-01-01

    For the investigation of air/water slug flow, a horizontal channel with rectangular cross-section was built at Forschungszentrum Rossendorf. The channel allows the investigation of air/water co- and counter-current flows at atmospheric pressure, especially the slug behaviour. Optical measurements were performed with a high-speed video camera, and were complemented by simultaneous dynamic pressure measurements. Moreover velocity-fields were measured using particle image velocimetry (PIV). A CFD simulation of the stratified co-current flow was performed using the code CFX-5, applying the Euler-Euler two fluid model with the free surface option. The grid contains 4 x 10 5 control volumes. The turbulence was modelled separately for each phase using the k-ω based shear stress transport (SST) turbulence model. To achieve wave generation in such a short channel, the inlet water level had to be varied in time. For this purpose, the water level history was taken from a recorded image sequence and set as time-dependent boundary condition at the model inlet. The results show a wave formation up to slug development with closure of the whole channel cross-section and consequently an increase of the pressure level behind the slug. Despite unsteady conditions at the inlet of the test channel and simplified initial conditions in the model, the slug simulation with CFX is in good qualitative agreement with the experiment, while the slug length increases during its progression, witch was not observed in reality. (orig.)

  11. Thermodynamic and transport properties of air/water mixtures

    Science.gov (United States)

    Fessler, T. E.

    1981-01-01

    Subroutine WETAIR calculates properties at nearly 1,500 K and 4,500 atmospheres. Necessary inputs are assigned values of combinations of density, pressure, temperature, and entropy. Interpolation of property tables obtains dry air and water (steam) properties, and simple mixing laws calculate properties of air/water mixture. WETAIR is used to test gas turbine engines and components operating in relatively humid air. Program is written in SFTRAN and FORTRAN.

  12. The water needs for LDV transportation in the United States

    International Nuclear Information System (INIS)

    King, Carey W.; Webber, Michael E.; Duncan, Ian J.

    2010-01-01

    Concern over increased demand for petroleum, reliable fuel supply, and global climate change has resulted in the US government passing new Corporate Average Fuel Economy standards and a Renewable Fuels Standard. Consequently, the fuel mix for light duty vehicle (LDV) travel in the United States will change over the coming years. This paper explores the embodied water consumption and withdrawal associated with two projections for future fuel use in the US LDV sector. This analysis encompasses conventional and unconventional fossil fuels, corn ethanol, cellulosic ethanol, soy biodiesel, electricity, and hydrogen. The existing mandate in the US to blend ethanol into gasoline had effectively committed 3300 billion liters of irrigation water in 2005 (approximately 2.4% of US 2005 fresh water consumption) for producing fuel for LDVs. With current irrigation practices, fuel processing, and electricity generation, it is estimated that by 2030, approximately 14,000 billion liters of water per year will be consumed and 23,000-27,000 billion liters withdrawn to produce fuels used in LDVs. Irrigation for biofuels dominates projected water usage for LDV travel, but other fuels (coal to liquids, oil shale, and electricity via plug-in hybrid vehicles) will also contribute appreciably to future water consumption and withdrawal, especially on a regional basis. (author)

  13. Studies and research concerning BNFP: transportation of radioactive material by water

    International Nuclear Information System (INIS)

    Anderson, R.T.

    1980-11-01

    Currently there are many limitations imposed on the shipment of radioactive material from nuclear power plants. In this regard, many questions have arisen related to the feasibility of substituting water transportation of these materials as a backup or supplement to the highway and rail modes which are now in use. This study addresses the results of studies performed by Allied-General Nuclear Services concerning the water transportation of spent nuclear fuel and radwaste materials. The report presents both an overview of the possible applications, problems, and means of solution, and specific information related to one particular site. In particular, a detailed case study of a nuclear plant site located on a navigable waterway (Chesapeake Bay) was made. The study concludes that there are some real advantages in using water transport, which are particularly evident if a site is not served by rail or its primary transport route lies near populous areas. Whereas, water transport has been used extensively in Europe and Japan, it has been virtually bypassed in the United States. A recommendation is made to continue examination of water transport, including the development of necessary standards for possible future operations

  14. Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model

    International Nuclear Information System (INIS)

    Tucci, P.

    2001-01-01

    This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M and O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment

  15. Water vapor and gas transport through a poly (butylene terephthalate) poly (ethylene oxide) block copolymer

    NARCIS (Netherlands)

    Metz, S.J.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2002-01-01

    In this paper the transport behavior of water vapor and nitrogen in a poly(butylene terephthalate) poly (ethylene oxide) block copolymer is discussed. This polymer has a high solubility for water (300 cm3 (STP)/cm3 polymer at activity 0.9). A new permeation set up has been built to determine the

  16. Numerical modeling of coupled water flow and heat transport in soil and snow

    Science.gov (United States)

    Thijs J. Kelleners; Jeremy Koonce; Rose Shillito; Jelle Dijkema; Markus Berli; Michael H. Young; John M. Frank; William Massman

    2016-01-01

    A one-dimensional vertical numerical model for coupled water flow and heat transport in soil and snow was modified to include all three phases of water: vapor, liquid, and ice. The top boundary condition in the model is driven by incoming precipitation and the surface energy balance. The model was applied to three different terrestrial systems: A warm desert bare...

  17. Transport and transfer rates in the waters of the continental shelf. Annual report

    International Nuclear Information System (INIS)

    Biscaye, P.E.

    1980-09-01

    The goal of govern project is to understand and quantify the processes that the transport and dispersal of energy-related pollutants introduced to the waters of the continental shelf and slope. The report is divided into sections dealing with processes associated with suspended solids; processes associated with sediments sinks for radionuclides and other pollutants; and spreading of water characteristics and species in solution

  18. Functional magnetic resonance microscopy of long- and short-distance water transport in trees

    NARCIS (Netherlands)

    Homan, N.

    2009-01-01

    Due to their long life span, changing climatic conditions are of particular importance for trees. Climate changes will affect the water balance, which can become an important limiting factor for photosynthesis and growth. Long-distance water transport in trees is directly related to the

  19. Use of orthonormal polynomials to fit energy spectrum data for water transported through membrane

    International Nuclear Information System (INIS)

    Bogdanova, N.; Todorova, L.

    2001-01-01

    A new application of our approach with orthonormal polynomials to curve fitting is given when both variables have errors. We approximate and describe data of a new effect due to change of water energy spectrum as a result of water transport in a porous membrane

  20. Geological and hydrological investigation and mass transport study in a fractured system at the Kamaishi Mine

    International Nuclear Information System (INIS)

    Uchida, Masahiro; Sawada, Atsushi; Senba, Takeshi; Miyoshi, Tadakazu; Shimo, Michito; Yamamoto, Hajime; Takahara, Hiroyuki; Doe, T.W.; Cladouhos, T.T.

    1999-01-01

    The hydrologic investigations demonstrate clearly that variable connectivity of fracture networks can lead to compartmentalised flow systems. These compartments may be significant for understanding flow and transport in a repository site. The experiment shows that complex geometries of fracture networks can be deduced by simple, but careful monitoring of drilling and testing operations. Inadequate isolation of conducting features during experiment area development may short-circuit the flow system and make geometric assessment difficult or impossible. Once conducting features are identified, tracer tests can successfully provide information on transport properties. (author)

  1. Intact plant MRI for the study of cell water relations, membrane permeability, cell-to-cell and long distance water transport

    NARCIS (Netherlands)

    As, van H.

    2007-01-01

    Water content and hydraulic conductivity, including transport within cells, over membranes, cell-to-cell, and long-distance xylem and phloem transport, are strongly affected by plant water stress. By being able to measure these transport processes non-invasely in the intact plant situation in

  2. Taxonomic investigations of bacteriophage sensitive bacteria isolated from marine waters

    Science.gov (United States)

    Moebus, K.; Nattkemper, H.

    1983-12-01

    Based on 28 criteria the taxonomy of 366 phage sensitive bacterial strains isolated from marine waters (Atlantic between European continental shelf and Sargasso Sea, Bay of Biscay, North Sea near Helgoland) was investigated. Seventy-eight phage-intensity strains derived from the same Atlantic Ocean regions as the sensitive ones were tested for comparison. While in the latter considerable diversity was observed, the results obtained with the phage-sensitive bacteria are characterized by stupendous uniformity. 362 of the 366 strains are assigned to the family Vibrionaceae, some 280 of which belong to the genus Vibrio. As discussed, this taxonomic uniformity among the phage-sensitive bacteria is assumed to be an artifact mainly caused by the type of enrichment culture employed for the isolation of all but a few bacteriophage strains used and, to a lesser degree, by characteristics of the bacterial populations encountered.

  3. Some analytic diagnostic models for transport processes in estuarine and coastal waters

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2001-03-01

    Advection and dispersion processes in estuarine and coastal waters are briefly reviewed. Beginning from the basic macroscopic equations of transport for a substance diluted or suspended in the considered body of water,several levels of filtering in time and space are described and applied to obtain suitable diagnostic mathematical models both with scale effects and gaussian.The solutions of the aforementioned models,for initial distributions and boundary conditions with enough symmetry,are discussed, as well as their applications to a parameter characterization of the transport properties of the receiving body of water

  4. Reactive Transport Modeling Investigation of High Dissolved Sulfide Concentrations in Sedimentary Basin Rocks

    Science.gov (United States)

    Xie, M.; Mayer, U. K.; MacQuarrie, K. T. B.

    2017-12-01

    Water with total dissolved sulfide in excess of 1 mmol L-1is widely found in groundwater at intermediate depths in sedimentary basins, including regions of the Michigan basin in southeastern Ontario, Canada. Conversely, at deeper and shallower depths, relatively low total dissolved sulfide concentrations have been reported. The mechanisms responsible for the occurrence of these brackish sulfide-containing waters are not fully understood. Anaerobic microbial sulfate reduction is a common process resulting in the formation of high sulfide concentrations. Sulfate reduction rates depend on many factors including the concentration of sulfate, the abundance of organic substances, redox conditions, temperature, salinity and the species of sulfate reducing bacteria (SRB). A sedimentary basin-specific conceptual model considering the effect of salinity on the rate of sulfate reduction was developed and implemented in the reactive transport model MIN3P-THCm. Generic 2D basin-scale simulations were undertaken to provide a potential explanation for the dissolved sulfide distribution observed in the Michigan basin. The model is 440 km in the horizontal dimension and 4 km in depth, and contains fourteen sedimentary rock units including shales, sandstones, limestones, dolostone and evaporites. The main processes considered are non-isothermal density dependent flow, kinetically-controlled mineral dissolution/precipitation and its feedback on hydraulic properties, cation exchange, redox reactions, biogenic sulfate reduction, and hydromechanical coupling due to glaciation-deglaciation events. Two scenarios were investigated focusing on conditions during an interglacial period and the transient evolution during a glaciation-deglaciation cycle. Inter-glaciation simulations illustrate that the presence of high salinity brines strongly suppress biogenic sulfate reduction. The transient simulations show that glaciation-deglaciation cycles can have an impact on the maximum depth of

  5. Investigation of water films on fuel rods in boiling water reactors using neutron tomography

    International Nuclear Information System (INIS)

    Lanthen, Jonas

    2006-09-01

    In a boiling water reactor, thin films of liquid water around the fuel rods play a very important role in cooling the fuel, and evaporation of the film can lead to fuel damage. If the thickness of the water film could be measured accurately the reactor operation could be both safer and more economical. In this thesis, the possibility to use neutron tomography, to study thin water films on fuel rods in an experimental nuclear fuel set-up, has been investigated. The main tool for this has been a computer simulation software. The simulations have shown that very thin water films, down to around 20 pm, can be seen on fuel rods in an experimental set-up using neutron tomography. The spatial resolution needed to obtain this result is around 300 pm. A suitable detector system for this kind of experiment would be plastic fiber scintillators combined with a CCD camera. As a neutron source it would be possible to use a D-D neutron generator, which generates neutrons with energies of 2.5 MeV. Using a neutron generator with a high enough neutron yield and a detector with high enough detection efficiency, a neutron tomography to measure thin water films should take no longer than 25 - 30 minutes

  6. Laboratory investigation of the role of desorption kinetics on americium transport associated with bentonite colloids.

    Science.gov (United States)

    Dittrich, Timothy Mark; Boukhalfa, Hakim; Ware, Stuart Douglas; Reimus, Paul William

    2015-10-01

    Understanding the parameters that control colloid-mediated transport of radionuclides is important for the safe disposal of used nuclear fuel. We report an experimental and reactive transport modeling examination of americium transport in a groundwater-bentonite-fracture fill material system. A series of batch sorption and column transport experiments were conducted to determine the role of desorption kinetics from bentonite colloids in the transport of americium through fracture materials. We used fracture fill material from a shear zone in altered granodiorite collected from the Grimsel Test Site (GTS) in Switzerland and colloidal suspensions generated from FEBEX bentonite, a potential repository backfill material. The colloidal suspension (100 mg L(-1)) was prepared in synthetic groundwater that matched the natural water chemistry at GTS and was spiked with 5.5 × 10(-10) M (241)Am. Batch characterizations indicated that 97% of the americium in the stock suspension was adsorbed to the colloids. Breakthrough experiments conducted by injecting the americium colloidal suspension through three identical columns in series, each with mean residence times of 6 h, show that more than 95% of the bentonite colloids were transported through each of the columns, with modeled colloid filtration rates (k(f)) of 0.01-0.02 h(-1). Am recoveries in each column were 55-60%, and Am desorption rate constants from the colloids, determined from 1-D transport modeling, were 0.96, 0.98, and 0.91 h(-1) in the three columns, respectively. The consistency in Am recoveries and desorption rate constants in each column indicates that the Am was not associated with binding sites of widely-varying strengths on the colloids, as one binding site with fast kinetics represented the system accurately for all three sequential columns. Our data suggest that colloid-mediated transport of Am in a bentonite-fracture fill material system is unlikely to result in transport over long distance scales because

  7. Water-mediated energy transport and structure across a protein-protein interface

    Science.gov (United States)

    Leitner, David

    2010-03-01

    Water molecules embedded within proteins or at the interface between globules play a central role in folding and function. We discuss the influence of interfacial water molecules on energy transport and structure, specifically the role of water at the interface between the two globules of the homodimeric hemoglobin from Scapharca inaequivalvis, which binds oxygen cooperatively. We have studied the water-mediated energy transport in this protein with communication maps and nonequilibrium molecular simulations of energy flow, which reveal the disproportionate amount of energy carried by the water molecules, particularly across the interface, i.e., a larger thermal conductivity of the interfacial waters compared with other parts of the protein, promoting hydrogen bond rearrangements at the interface.

  8. Hydrogeologic settings and groundwater-flow simulations for regional investigations of the transport of anthropogenic and natural contaminants to public-supply wells—Investigations begun in 2004

    Science.gov (United States)

    Eberts, Sandra M.

    2011-01-01

    A study of the Transport of Anthropogenic and Natural Contaminants to public-supply wells (TANC study) was begun in 2001 as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. The study was designed to shed light on factors that affect the vulnerability of groundwater and, more specifically, water from public-supply wells to contamination to provide a context for the NAWQA Program's earlier finding of mixtures of contaminants at low concentrations in groundwater near the water table in urban areas across the Nation. The TANC study has included investigations at both the regional (tens to thousands of square kilometers) and local (generally less than 25 square kilometers) scales. At the regional scale, the approach to investigation involves refining conceptual models of groundwater flow in hydrologically distinct settings and then constructing or updating a groundwater-flow model with particle tracking for each setting to help quantify regional water budgets, public-supply well contributing areas (areas contributing recharge to wells and zones of contribution for wells), and traveltimes from recharge areas to selected wells. A great deal of information about each contributing area is captured from the model output, including values for 170 variables that describe physical and (or) geochemical characteristics of the contributing areas. The information is subsequently stored in a relational database. Retrospective water-quality data from monitoring, domestic, and many of the public-supply wells, as well as data from newly collected samples at selected public-supply wells, also are stored in the database and are used with the model output to help discern the more important factors affecting vulnerability in many, if not most, settings. The study began with investigations in seven regional areas, and it benefits from being conducted as part of the NAWQA Program, in which consistent methods are used so that meaningful comparisons can be

  9. Profiling of sugar transporter genes in grapevine coping with water deficit.

    Science.gov (United States)

    Medici, Anna; Laloi, Maryse; Atanassova, Rossitza

    2014-11-03

    The profiling of grapevine (Vitis vinifera L.) genes under water deficit was specifically targeted to sugar transporters. Leaf water status was characterized by physiological parameters and soluble sugars content. The expression analysis provided evidence that VvHT1 hexose transporter gene was strongly down-regulated by the increased sugar content under mild water-deficit. The genes of monosaccharide transporter VvHT5, sucrose carrier VvSUC11, vacuolar invertase VvGIN2 and grape ASR (ABA, stress, ripening) were up-regulated under severe water stress. Their regulation in a drought-ABA signalling network and possible roles in complex interdependence between sugar subcellular partitioning and cell influx/efflux under Grapevine acclimation to dehydration are discussed. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  10. Climate change and the impact of increased rainfall variability on sediment transport and catchment scale water quality

    Science.gov (United States)

    Hancock, G. R.; Willgoose, G. R.; Cohen, S.

    2009-12-01

    Recently there has been recognition that changing climate will affect rainfall and storm patterns with research directed to examine how the global hydrological cycle will respond to climate change. This study investigates the effect of different rainfall patterns on erosion and resultant water quality for a well studied tropical monsoonal catchment that is undisturbed by Europeans in the Northern Territory, Australia. Water quality has a large affect on a range of aquatic flora and fauna and a significant change in sediment could have impacts on the aquatic ecosystems. There have been several studies of the effect of climate change on rainfall patterns in the study area with projections indicating a significant increase in storm activity. Therefore it is important that the impact of this variability be assessed in terms of catchment hydrology, sediment transport and water quality. Here a numerical model of erosion and hydrology (CAESAR) is used to assess several different rainfall scenarios over a 1000 year modelled period. The results show that that increased rainfall amount and intensity increases sediment transport rates but predicted water quality was variable and non-linear but within the range of measured field data for the catchment and region. Therefore an assessment of sediment transport and water quality is a significant and complex issue that requires further understandings of the role of biophysical feedbacks such as vegetation as well as the role of humans in managing landscapes (i.e. controlled and uncontrolled fire). The study provides a robust methodology for assessing the impact of enhanced climate variability on sediment transport and water quality.

  11. Water Transport and the Evolution of CM Parent Bodies

    Science.gov (United States)

    Coker, Rob; Cohen, Barbara

    2014-01-01

    Meteorites have amino acids and hydrated minerals which constrain the peak temperature ranges they have experienced. CMs in particular have a narrow range (273-325K). Bulk fluid motion during hydration constrained to small scales (less than mm). Some asteroids are known to have hydrated minerals on their surfaces. It is presumed these two facts may be related. Problem: hydration only occurs (significantly) with liquid water; melting water only occurs early on in nebula (1-10 Myrs ANC); in nebula asteroid surface temperature very cold (approximately 150K). Can indigenous alteration produce CMs and/or surface hydration?

  12. Role of air-water interfaces in colloid transport in porous media: A review

    Science.gov (United States)

    Flury, Markus; Aramrak, Surachet

    2017-07-01

    Air-water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air-water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air-water interfaces in porous media. We discuss the theory of colloid/air-water interface interactions, based on the different forces acting between colloids and the air-water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air-water interface because most subsurface colloids and the air-water are negatively charged. However, hydrophobic interactions can lead to attraction to the air-water interface. When colloids are at the air-water interface, capillary forces are usually dominant over other forces. Moving air-water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air-water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air-water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air-water-solid interface line, causing colloid retention and immobilization. Air-water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface

  13. Investigations into the binding of 125I-calmodulin to CA++ transport ATPase of human erythrocytes

    International Nuclear Information System (INIS)

    Sterk, V.

    1983-01-01

    The study described was carried out in order to investigate the binding of 125 I-calmodulin to Ca ++ transport ATPase using different Ca ++ concentrations and temperatures. The data obtained from these experiments were subsequently analysed in such as a way as to yield meaningful information relating to the mechanisms underlying the attachment of calmodulin to Ca ++ transport ATPase, the % proportion of membrane protein that was attributable to the enzyme as well as the number of calmodulin receptor sites on the individual erythrocytes, etc. Comparisons with data from the relevant literature permitted conclusions to be drawn concerning the mode of Ca ++ transport at the level of the erythrocytes. A new methodology and processing technique had to be developed prior to the beginning of the experiments. (orig./MG) [de

  14. Investigation of Trihalomethanes in Drinking Water of Abbas Abad Water Treatment Plant

    Directory of Open Access Journals (Sweden)

    Kiani R

    2017-06-01

    Full Text Available Introduction: Chlorination is the most common and successful method for disinfection of drinking water, especially in developing countries. However, due to the probability of formation of disinfection by-products especially Trihalomethanes (THMs that are known as hazardous and usually carcinogenic compounds, this study was conducted to assess the investigation of THMs in drinking water of Abbas Abad water treatment plant in 2015. Methods: In this study, 81 water samples were gathered during autumn season of 2015. Temperature, pH, Ec, turbidity, and residual chlorine were measured on site. After samples preparation in the laboratory, THMs concentrations were determined using gas chromatography. All statistical analyses were performed using the SPSS statistical package. Results: The results showed that the minimum and maximum mean concentrations (µg/l for bromodichloromethane were 1.47 ± 0.57 and 1.90 ± 0.26, for bromoform were 1.47 ± 0.35 and 2.36 ± 1.10, for dibromochloromethane were 1.47 ± 0.42 and 1.53 ± 0.55, and for chloroform were 3.40 ± 0.70 and 7.53 ± 1.00, and all compounds were determined for stations 1 and 3, respectively. Also comparing the mean concentrations of assessed THMs with ISIRI and World Health Organization (WHO Maximum Permissible Limits (MPL showed significant differences (P < 0.05. Thus, the mean concentrations of all Trihalomethanes compounds were significantly lower than the maximum permissible limits. Conclusions: Although the mean concentrations of THMs were lower than MPL, yet due to discharge of restaurants and gardens’ wastewater into the Abbas Abad River, pre-chlorination process of water in Abbas Abad water treatment plant, high retention time and increasing loss of foliage into the water, especially in autumn season, the formation of Trihalomethanes compounds could increase. Therefore, periodic monitoring of THMs in drinking water distribution network is recommended.

  15. The hydraulic transportation of thickened sludges | Slatter | Water SA

    African Journals Online (AJOL)

    Industries which pump sludges are under continuous pressure to decrease water content, and increase concentration. Environmentally superior disposal techniques are demanding that such sludges have high mechanical strength properties. This results in a sludge with an increasing viscous character. At high ...

  16. Quantitative analysis of soil chromatography. I. Water and radionuclide transport

    International Nuclear Information System (INIS)

    Reeves, M.; Francis, C.W.; Duguid, J.O.

    1977-12-01

    Soil chromatography has been used successfully to evaluate relative mobilities of pesticides and nuclides in soils. Its major advantage over the commonly used suspension technique is that it more accurately simulates field conditions. Under such conditions the number of potential exchange sites is limited both by the structure of the soil matrix and by the manner in which the carrier fluid moves through this structure. The major limitation of the chromatographic method, however, has been its qualitative nature. This document represents an effort to counter this objection. A theoretical basis is specified for the transport both of the carrier eluting fluid and of the dissolved constituent. A computer program based on this theory is developed which optimizes the fit of theoretical data to experimental data by automatically adjusting the transport parameters, one of which is the distribution coefficient k/sub d/. This analysis procedure thus constitutes an integral part of the soil chromatographic method, by means of which mobilities of nuclides and other dissolved constituents in soils may be quantified

  17. Quantitative analysis of soil chromatography. I. Water and radionuclide transport

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, M.; Francis, C.W.; Duguid, J.O.

    1977-12-01

    Soil chromatography has been used successfully to evaluate relative mobilities of pesticides and nuclides in soils. Its major advantage over the commonly used suspension technique is that it more accurately simulates field conditions. Under such conditions the number of potential exchange sites is limited both by the structure of the soil matrix and by the manner in which the carrier fluid moves through this structure. The major limitation of the chromatographic method, however, has been its qualitative nature. This document represents an effort to counter this objection. A theoretical basis is specified for the transport both of the carrier eluting fluid and of the dissolved constituent. A computer program based on this theory is developed which optimizes the fit of theoretical data to experimental data by automatically adjusting the transport parameters, one of which is the distribution coefficient k/sub d/. This analysis procedure thus constitutes an integral part of the soil chromatographic method, by means of which mobilities of nuclides and other dissolved constituents in soils may be quantified.

  18. Extension of Applicability of integral neutron transport theory in reactor cell and core investigation

    International Nuclear Information System (INIS)

    Pop-Jordanov, J.; Bosevski, T.; Kocic, A.; Altiparmakov, D.

    1980-01-01

    A Space-Point Energy-Group integral transport theory method (SPEG) is developed and applied to the local and global calculations of the Yugoslav RA reactor. Compared to other integral transport theory methods, the SPEG distinguishes by (1) the arbitrary order of the polynomial, (2) the effective determination of integral parameters through point flux values, (3) the use of neutron balance condition. as a posterior measure of the accuracy of the calculation and (4) the elimination of the subdivisions- into zones, in realistic cases. In addition, different direct (collision probability) and indirect (Monte Carlo) approaches to integral transport theory have been investigated and Some effective acceleration procedures introduced. The study was performed on three test problems in plane and cylindrical geometry, as well as on the nine-region cell of the RA reactor. In particular, the limitations of the integral transport theory including its non-applicability to optically large material regions and to global reactor calculations were examined. The proposed strictly multipoint approach, avoiding the subdivision into zones and groups, seems to provide a good starting point to overcome these limitations of the integral transport theory. (author)

  19. Experimental and Numerical Investigations on Colloid-facilitated Plutonium Reactive Transport in Fractured Tuffaceous Rocks

    Science.gov (United States)

    Dai, Z.; Wolfsberg, A. V.; Zhu, L.; Reimus, P. W.

    2017-12-01

    Colloids have the potential to enhance mobility of strongly sorbing radionuclide contaminants in fractured rocks at underground nuclear test sites. This study presents an experimental and numerical investigation of colloid-facilitated plutonium reactive transport in fractured porous media for identifying plutonium sorption/filtration processes. The transport parameters for dispersion, diffusion, sorption, and filtration are estimated with inverse modeling for minimizing the least squares objective function of multicomponent concentration data from multiple transport experiments with the Shuffled Complex Evolution Metropolis (SCEM). Capitalizing on an unplanned experimental artifact that led to colloid formation and migration, we adopt a stepwise strategy to first interpret the data from each experiment separately and then to incorporate multiple experiments simultaneously to identify a suite of plutonium-colloid transport processes. Nonequilibrium or kinetic attachment and detachment of plutonium-colloid in fractures was clearly demonstrated and captured in the inverted modeling parameters along with estimates of the source plutonium fraction that formed plutonium-colloids. The results from this study provide valuable insights for understanding the transport mechanisms and environmental impacts of plutonium in fractured formations and groundwater aquifers.

  20. Mathematical simulation of sediment and contaminant transport in surface waters. Annual report, October 1977--September 1978

    International Nuclear Information System (INIS)

    Onishi, Y.; Arnold, E.M.; Serne, R.J.; Cowan, C.E.; Thompson, F.L.; Mayer, D.W.

    1979-01-01

    Various pathways exist for exposure of humans and biota to radioactive materials released from nuclear facilities. Hydrologic transport (liquid pathway) is one element in the evaluation of the total radiation dose to man. Mathematical models supported by well-planned field data collection programs can be useful tools in assessing the hydrologic transport and ultimate fate of radionuclides. Radionuclides with high distribution coefficients or radionuclides in surface waters with high suspended sediment concentrations are, to a great extent, adsorbed by river and marine sediments. Thus, otherwise dilute contaminants are concentrated. Contaminated sediments may be deposited on the river and ocean beds creating a significant pathway to man. Contaminated bed sediment in turn may become a long-term source of pollution through desorption and resuspension. In order to assess migration and accumulation of radionuclides in surface waters, mathematical models must correctly simulate essential mechanisms of radionuclide transport. The objectives of this study were: (1) to conduct a critical review of (a) radionuclide transport models as well as sediment transport and representative water quality models in rivers, estuaries, oceans, lakes, and reservoirs, and (b) adsorption and desorption mechanisms of radionuclides with sediments in surface waters; (2) to synthesize a mathematical model capable of predicting short- and long-term transport and accumulation of radionuclides in marine environments

  1. Using Lagrangian sampling to study water quality during downstream transport in the San Luis Drain, California, USA

    Science.gov (United States)

    Volkmar, E.C.; Dahlgren, R.A.; Stringfellow, W.T.; Henson, S.S.; Borglin, S.E.; Kendall, C.; Van Nieuwenhuyse, E. E.

    2011-01-01

    To investigate the mechanism for diel (24h) changes commonly observed at fixed sampling locations and how these diel changes relate to downstream transport in hypereutrophic surface waters, we studied a parcel of agricultural drainage water as it traveled for 84h in a concrete-lined channel having no additional water inputs or outputs. Algal fluorescence, dissolved oxygen, temperature, pH, conductivity, and turbidity were measured every 30min. Grab samples were collected every 2h for water quality analyses, including nutrients, suspended sediment, and chlorophyll/pheophytin. Strong diel patterns were observed for dissolved oxygen, pH, and temperature within the parcel of water. In contrast, algal pigments and nitrate did not exhibit diel patterns within the parcel of water, but did exhibit strong diel patterns for samples collected at a fixed sampling location. The diel patterns observed at fixed sampling locations for these constituents can be attributed to algal growth during the day and downstream transport (washout) of algae at night. Algal pigments showed a rapid daytime increase during the first 48h followed by a general decrease for the remainder of the study, possibly due to sedimentation and photobleaching. Algal growth (primarily diatoms) was apparent each day during the study, as measured by increasing dissolved oxygen concentrations, despite low phosphate concentrations (<0.01mgL-1). ?? 2011 Elsevier B.V.

  2. Effects of clamping force on the water transport and performance of a PEM (proton electrolyte membrane) fuel cell with relative humidity and current density

    International Nuclear Information System (INIS)

    Cha, Dowon; Ahn, Jae Hwan; Kim, Hyung Soon; Kim, Yongchan

    2015-01-01

    The clamping force should be applied to a proton electrolyte membrane (PEM) fuel cell due to its structural characteristics. The clamping force affects the ohmic and mass transport resistances in the PEM fuel cell. In this study, the effects of the clamping force on the water transport and performance characteristics of a PEM fuel cell are experimentally investigated with variations in the relative humidity and current density. The water transport characteristics were analyzed by calculating the net drag coefficient. The ohmic resistance decreased with the increase in the clamping force due to the reduced contact resistance and more even membrane hydration. However, the mass transport resistance increased with the increase in the clamping force due to the gas diffusion layer compression. The net drag coefficient decreased with the increase in the clamping force due to high water back-diffusion. Additionally, the relationship between the total resistance and the net drag coefficient was investigated. - Highlights: • Effects of clamping force on the performance of a PEM fuel cell are investigated. • Water transport characteristics are analyzed using net drag coefficient. • Ohmic resistance decreased with clamping force, but mass transport resistance increased. • Net drag coefficient decreased with the increase in clamping force. • Total resistance was significantly degraded for a net drag coefficient below 0.2.

  3. Seasonal Water Transport in the Atmosphere of Mars: Applications of a Mars General Circulation Model Using Mars Global Surveyor Data

    Science.gov (United States)

    Hollingsworth, Jeffery L.; Bridger, Alison F. C.; Haberle, Robert M.

    1999-01-01

    This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Center and San Jose State University, Department of Meteorology. We present below a summary of progress made during the duration of this JRI. The focus of this JRI has been to investigate seasonal water vapor transport in the atmosphere of Mars and its effects on the planet's present climate. To this end, the primary task has been to adapt a new dynamical processor for the adiabatic tendencies of the atmospheric circulation into the NASA Ames Mars general circulation model (MGCM). Using identical boundary and initial conditions, several comparative tests between the new and old MGCMs have been performed and the nature of the simulated circulations have been diagnosed. With confidence that the updated version of the Ames MGCM produces quite similar mean and eddy circulation statistics, the new climate model is well poised as a tool to pursue fundamental questions related to the spatial and seasonal variations of atmospheric water vapor on Mars, and to explore exchanges of water with non-atmospheric reservoirs and transport within its atmosphere. In particular, the role of surface sources and sinks can be explored, the range of water-vapor saturation altitudes can be investigated, and plausible precipitation mechanisms can be studied, for a range of atmospheric dust loadings. Such future investigations can contribute to a comprehensive study of surface inventories, exchange mechanisms, and the relative importance of atmospheric transport Mars' water cycle. A listing of presentations made and manuscripts submitted during the course of this project is provided.

  4. Investigation of silicate surface chemistry and reaction mechanisms associated with mass transport in geologic media

    International Nuclear Information System (INIS)

    White, A.F.; Perry, D.L.

    1982-01-01

    The concentration and rate of transport of radionuclides through geologic media can be strongly influenced by the extent of sorption on aquifer surfaces. Over time intervals relevant to such transport processes, rock and mineral surfaces cannot be considered as inert, unreactive substrates but rather as groundwater/solidphase interfaces which are commonly in a state of natural or artificially induced disequilibrium. The goal of the present research is to define experimentally the type of water/rock interactions that will influence surface chemistry and hence sorption characteristics and capacities of natural aquifers. As wide a range of silicate minerals as possible was selected for study to represent rock-forming minerals in basalt, tuff, and granite. The minerals include K-feldspar, plagioclase feldspar, olivine, hornblende, biotite, and volcanic glass

  5. Transport and metabolic degradation of hydrogen peroxide in Chara corallina: model calculations and measurements with the pressure probe suggest transport of H(2)O(2) across water channels.

    Science.gov (United States)

    Henzler, T; Steudle, E

    2000-12-01

    A mathematical model is presented that describes permeation of hydrogen peroxide across a cell membrane and the implications of solute decomposition by catalase inside the cell. The model was checked and analysed by means of a numerical calculation that raised predictions for measured osmotic pressure relaxation curves. Predictions were tested with isolated internodal cells of CHARA: corallina, a model system for investigating interactions between water and solute transport in plant cells. Series of biphasic osmotic pressure relaxation curves with different concentrations of H(2)O(2) of up to 350 mol m(-3) are presented. A detailed description of determination of permeability (P(s)) and reflection coefficients (sigma(s)) for H(2)O(2) is given in the presence of the chemical reaction in the cell. Mean values were P(s)=(3.6+/-1.0) 10(-6) m s(-1) and sigma(s)=(0.33+/-0.12) (+/-SD, N=6 cells). Besides transport properties, coefficients for the catalase reaction following a Michaelis-Menten type of kinetics were determined. Mean values of the Michaelis constant (k(M)) and the maximum rate of decompositon (v(max)) were k(M)=(85+/-55) mol m(-3) and v(max)=(49+/-40) nmol (s cell)(-1), respectively. The absolute values of P:(s) and sigma(s) of H(2)O(2) indicated that hydrogen peroxide, a molecule with chemical properties close to that of water, uses water channels (aquaporins) to cross the cell membrane rapidly. When water channels were inhibited with the blocker mercuric chloride (HgCl(2)), the permeabilities of both water and H(2)O(2) were substantially reduced. In fact, for the latter, it was not measurable. It is suggested that some of the water channels in CHARA: (and, perhaps, in other species) serve as 'peroxoporins' rather than as 'aquaporins'.

  6. Biofuel scenarios in a water perspective: the global blue and green water footprint of road transport in 2030

    NARCIS (Netherlands)

    van Lienden, A.R.; Gerbens-Leenes, Winnie; Hoekstra, Arjen Ysbert; van der Meer, Theodorus H.

    2010-01-01

    The trend towards substitution of conventional transport fuels by biofuels requires additional water. The EU aims In the last two centuries, fossil fuels have been our major source of energy. However, issues concerning energy security and the quality of the environment have given an impulse to the

  7. Investigation of bacterial transport in the large-block test, a thermally perturbed block of Topopah Spring tuff

    International Nuclear Information System (INIS)

    Chen, C.I.; Meike, A.; Chuu, Y.J.; Sawvel, A.; Lin, W.

    1999-01-01

    Transport of bacteria is investigated as part of the Large-Block Test (LBT), a thermally perturbed block of Topopah Spring tuff. Two bacterial species, Bacillus subtilis and Arthrobacter oxydans, were isolated from the Yucca Mountain Tuff. Natural mutants that can grow under the simultaneous presence of the two antibiotics, streptomycin and rifampicin, were selected from these species by laboratory procedures, cultured, and injected into the five heater boreholes of the large block hours before heating was initiated. The temperature, as measured 5 cm above one of the heater boreholes, rose slowly over a matter of months to a maximum of 142 C and to 60 C at the top and bottom of the block. Samples were collected from boreholes located approximately 5 ft below the injection points. Double-drug-resistant microbes also appeared in the heater boreholes where the temperature had been sustainably high throughout the test. The number of double-drug-resistant bacteria that were identified in the collection boreholes increased with time until the heater was deactivated. Negative indications in the collection holes after the heater was deactivated support the supposition that these bacteria were the species that were injected. An apparent homogeneous distribution among the collection boreholes suggests no pattern to the migration of bacteria through the block. The relationship between bacterial migration and the movement of water is not yet understood. These observations indicate the possibility of rapid bacterial transport in a thermally perturbed geologic setting. The implications for colloid transport need to be reviewed

  8. Transport behaviour of xenobiotic micropollutants in surface waters - an experimental assessment

    Science.gov (United States)

    Schwientek, Marc; Kuch, Bertram; Rügner, Hermann; Dobramysl, Lorenz; Grathwohl, Peter

    2013-04-01

    Xenobiotics are substances that do not exist in natural systems but are increasingly produced by industrial processes and introduced into the environment. While many of these compounds are eliminated in waste water treatment plants, some are only barely degraded and are discharged into receiving water bodies. Often little is known about their acute or chronic toxicity and even less about their persistence or transport behaviour in aquatic systems. In the present study, the stability and turnover of selected micropollutants along a 7.5 km long segment of the River Ammer in Southwest Germany was investigated (catchment area 134 km²). This stream carries a proportion of treated wastewater which is clearly above the average in German rivers, mainly supplied by a major waste water treatment plant at the upstream end of the studied stream segment. An experimental mass balance approach was chosen where in- and outflow of water and target compounds into and out of the balanced stream segment was measured during base flow conditions. To cover a complete diurnal cycle of wastewater input, pooled samples were collected every 2 h over a sampling period of 24 h. A comparison of bulk mass fluxes showed that carbamazepine, a pharmaceutical, and phosphorous flame retardants, such as TCPP, behave conservative under the given conditions. Some retention was observed for the disinfectant product Triclosan and some polycyclic musk fragrances (e.g., HHCB). TAED, a bleaching activator used in detergents, was completely eliminated along the stream segment. The outcome of the experiment demonstrates the very different persistence of some widely-used micropollutants in aquatic systems. However, the mechanisms involved in their attenuation as well as the fate of the most persistent compounds still remain subject to further research.

  9. Investigation of Optimal Configuration of Solar Energy System Considering Configuration of Apparatuses and Electricity Transportation between Interprofessional Consumers

    Science.gov (United States)

    Ohkura, Masashi; Mori, Shunsuke

    This paper describes about a decision model for solar energy utilization and an investigation of optimal configuration of solar energy system considering electricity transportation between interprofessional consumers. Solar energy is effective energy source for CO2 reduction. Available collectable area for solar energy is limited to consumer's condition. A photovoltaic can supply electricity which is flexible. However its efficiency is low compared to solar heat collector. A solar heat collector has high efficiency. But heat demand varies with consumer type. We investigate optimal ratio of photovoltaic and solar heat collector in several condition. The result shows that solar heat collector is effective energy supply system for consumers which require high hot water demand in daytime. On the other hand, electrical heat pump for hot water supply varies optimal configuration of solar energy system due to the shift of energy source from gas to electricity. To introduce electrical heat pump for hot water supply increases the ratio of photovoltaic due to the increase in electricity demand. However, there is no consumer without solar heat collector. Therefore, solar heat collector does not compare with electrification of consumer.

  10. Investigation of the shape change of bio-flocs and its influence on mass transport using particle image velocimetry.

    Science.gov (United States)

    Ren, T T; Xiao, F; Sun, W J; Sun, F Y; Lam, K M; Li, X Y

    2014-01-01

    In this laboratory study, an advanced flow visualization technique - particle image velocimetry (PIV) - was employed to investigate the change of shape of activated sludge flocs in water and its influence on the material transport characteristics of the flocs. The continuous shape change of the bio-flocs that occurred within a very short period of time could be captured by the PIV system. The results demonstrate that the fluid turbulence caused the shift of parts of a floc from one side to the other in less than 200 ms. During the continuous shape change, the liquid within the floc was forced out of the floc, which was then refilled with the liquid from the surrounding flow. For the bio-flocs saturated with a tracer dye, it was shown that the dye could be released from the flocs at a faster rate when the flocs were swayed around in water. The experimental results indicate that frequent shape change of bio-flocs facilitates the exchange of fluid and materials between the floc interior and the surrounding water. This mass transfer mechanism can be more important than molecular diffusion and internal permeation to the function and behavior of particle aggregates, including bio-flocs, in natural waters and treatment systems.

  11. Impact of high speed civil transports on stratospheric ozone. A 2-D model investigation

    Energy Technology Data Exchange (ETDEWEB)

    Kinnison, D.E.; Connell, P.S. [Lawrence Livermore National Lab., CA (United States)

    1997-12-31

    This study investigates the effect on stratospheric ozone from a fleet of proposed High Speed Civil Transports (HSCTs). The new LLNL 2-D operator-split chemical-radiative-transport model of the troposphere and stratosphere is used for this HSCT investigation. This model is integrated in a diurnal manner, using an implicit numerical solver. Therefore, rate coefficients are not modified by any sort of diurnal average factor. This model also does not make any assumptions on lumping of chemical species into families. Comparisons to previous model-derived HSCT assessment of ozone change are made, both to the previous LLNL 2-D model and to other models from the international assessment modeling community. The sensitivity to the NO{sub x} emission index and sulfate surface area density is also explored. (author) 7 refs.

  12. High-Efficiency Fog Collector: Water Unidirectional Transport on Heterogeneous Rough Conical Wires.

    Science.gov (United States)

    Xu, Ting; Lin, Yucai; Zhang, Miaoxin; Shi, Weiwei; Zheng, Yongmei

    2016-12-27

    An artificial periodic roughness-gradient conical copper wire (PCCW) can be fabricated by inspiration from cactus spines and wet spider silks. PCCW can harvest fog on periodic points of the conical surface from air and transports the drops for a long distance without external force, which is attributed to dynamic as-released energy generated from drop deformation in drop coalescence, in addition to both gradients of geometric curve (inducing Laplace pressure) and periodic roughness (inducing surface energy difference). It is found that the ability of fog collection can be related to various tilt-angle wires, thus a fog collector with an array system of PCCWs is further designed to achieve a continuous process of efficient water collection. As a result, the effect of water collection on PCCWs is better than previous results. These findings are significant to develop and design materials with water collection and water transport for promising application in fogwater systems to ease the water crisis.

  13. A Laboratory Investigation of the Suspension, Transport, and Settling of Silver Carp Eggs Using Synthetic Surrogates.

    Directory of Open Access Journals (Sweden)

    Tatiana Garcia

    Full Text Available Asian carp eggs are semi-buoyant and must remain suspended in the water to survive, supported by the turbulence of the flow, until they hatch and develop the ability to swim. Analysis of the transport and dispersal patterns of Asian carp eggs will facilitate the development and implementation of control strategies to target the early life stages. Experimenting with Asian carp eggs is complicated due to practical issues of obtaining eggs in close proximity to experimental facilities and extensive handling of eggs tends to damage them. Herein, we describe laboratory experiments using styrene beads (4.85 mm diameter as synthetic surrogate eggs to mimic the physical properties of water-hardened silver carp eggs. The first set of experiments was completed in a rectangular vertical column filled with salt water. The salinity of the water was adjusted in an iterative fashion to obtain a close approximation of the fall velocity of the styrene beads to the mean fall velocity of silver carp water-hardened eggs. The terminal fall velocity of synthetic eggs was measured using an image processing method. The second set of experiments was performed in a temperature-controlled recirculatory flume with a sediment bed. The flume was filled with salt water, and synthetic eggs were allowed to drift under different flow conditions. Drifting behavior, suspension conditions, and settling characteristics of synthetic eggs were observed. At high velocities, eggs were suspended and distributed through the water column. Eggs that touched the sediment bed were re-entrained by the flow. Eggs saltated when they touched the bed, especially at moderate velocities and with a relatively flat bed. At lower velocities, some settling of the eggs was observed. With lower velocities and a flat bed, eggs were trapped near the walls of the flume. When bedforms were present, eggs were trapped in the lee of the bedforms in addition to being trapped near the flume walls. Results of this

  14. A Laboratory Investigation of the Suspension, Transport, and Settling of Silver Carp Eggs Using Synthetic Surrogates.

    Science.gov (United States)

    Garcia, Tatiana; Zuniga Zamalloa, Carlo; Jackson, P Ryan; Murphy, Elizabeth A; Garcia, Marcelo H

    2015-01-01

    Asian carp eggs are semi-buoyant and must remain suspended in the water to survive, supported by the turbulence of the flow, until they hatch and develop the ability to swim. Analysis of the transport and dispersal patterns of Asian carp eggs will facilitate the development and implementation of control strategies to target the early life stages. Experimenting with Asian carp eggs is complicated due to practical issues of obtaining eggs in close proximity to experimental facilities and extensive handling of eggs tends to damage them. Herein, we describe laboratory experiments using styrene beads (4.85 mm diameter) as synthetic surrogate eggs to mimic the physical properties of water-hardened silver carp eggs. The first set of experiments was completed in a rectangular vertical column filled with salt water. The salinity of the water was adjusted in an iterative fashion to obtain a close approximation of the fall velocity of the styrene beads to the mean fall velocity of silver carp water-hardened eggs. The terminal fall velocity of synthetic eggs was measured using an image processing method. The second set of experiments was performed in a temperature-controlled recirculatory flume with a sediment bed. The flume was filled with salt water, and synthetic eggs were allowed to drift under different flow conditions. Drifting behavior, suspension conditions, and settling characteristics of synthetic eggs were observed. At high velocities, eggs were suspended and distributed through the water column. Eggs that touched the sediment bed were re-entrained by the flow. Eggs saltated when they touched the bed, especially at moderate velocities and with a relatively flat bed. At lower velocities, some settling of the eggs was observed. With lower velocities and a flat bed, eggs were trapped near the walls of the flume. When bedforms were present, eggs were trapped in the lee of the bedforms in addition to being trapped near the flume walls. Results of this research study

  15. A laboratory investigation of the suspension, transport, and settling of silver carp eggs using synthetic surrogates

    Science.gov (United States)

    Garcia, Tatiana; Zuniga Zamalloa, Carlo; Jackson, P. Ryan; Murphy, Elizabeth A.; Garcia, Marcelo H.

    2015-01-01

    Asian carp eggs are semi-buoyant and must remain suspended in the water to survive, supported by the turbulence of the flow, until they hatch and develop the ability to swim. Analysis of the transport and dispersal patterns of Asian carp eggs will facilitate the development and implementation of control strategies to target the early life stages. Experimenting with Asian carp eggs is complicated due to practical issues of obtaining eggs in close proximity to experimental facilities and extensive handling of eggs tends to damage them. Herein, we describe laboratory experiments using styrene beads (4.85 mm diameter) as synthetic surrogate eggs to mimic the physical properties of water-hardened silver carp eggs. The first set of experiments was completed in a rectangular vertical column filled with salt water. The salinity of the water was adjusted in an iterative fashion to obtain a close approximation of the fall velocity of the styrene beads to the mean fall velocity of silver carp water-hardened eggs. The terminal fall velocity of synthetic eggs was measured using an image processing method. The second set of experiments was performed in a temperature-controlled recirculatory flume with a sediment bed. The flume was filled with salt water, and synthetic eggs were allowed to drift under different flow conditions. Drifting behavior, suspension conditions, and settling characteristics of synthetic eggs were observed. At high velocities, eggs were suspended and distributed through the water column. Eggs that touched the sediment bed were re-entrained by the flow. Eggs saltated when they touched the bed, especially at moderate velocities and with a relatively flat bed. At lower velocities, some settling of the eggs was observed. With lower velocities and a flat bed, eggs were trapped near the walls of the flume. When bedforms were present, eggs were trapped in the lee of the bedforms in addition to being trapped near the flume walls. Results of this research study

  16. Investigation of Beam Emittance and Beam Transport Line Optics on Polarization

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, Andrew [Northern Illinois U.; Syphers, Michael [Fermilab

    2017-10-06

    Effects of beam emittance, energy spread, optical parameters and magnet misalignment on beam polarization through particle transport systems are investigated. Particular emphasis will be placed on the beam lines being used at Fermilab for the development of the muon beam for the Muon g-2 experiment, including comparisons with the natural polarization resulting from pion decay, and comments on the development of systematic correlations among phase space variables.

  17. Transport of lead in secondary systems of PWR plants: laboratory and plant investigations

    International Nuclear Information System (INIS)

    Feron, D.; Rocher, A.; Nordmann, F.

    1992-01-01

    Both in France and abroad, abnormally high lead concentrations have been found in the deposits on certain steam generator tubes subject to combined inter and transgranular corrosion on the secondary side. Many potential sources of lead have been identified in PWR steam-water system, mainly at the turbine level. Tests on a loop (ORION) have shown that lead (as Pb or PbO) can transport from the condenser to the steam generator and that the contaminant mainly concentrates in flow restricted areas of steam generators

  18. Bacteriological investigation of ground water sources in selected ...

    African Journals Online (AJOL)

    cml

    2012-06-16

    Jun 16, 2012 ... Microbial contamination of ground water sources is a common problem in all the big cities, which ... To assess this, 39 water samples were collected from ... World health organization (WHO) recommends zero coliforms per 100 ml of water sample (Kahlown, 2006; Pakistan. Standards, 2002; WHO, 1996).

  19. Investigating water meter performance in developing countries: A ...

    African Journals Online (AJOL)

    High levels of water losses in distribution systems are the main challenge that water utilities in developing countries currently face. The water meter is an essential tool for both the utility and the customers to measure and monitor consumption. When metering is inefficient and coupled with low tariffs, the financial ...

  20. Influence of Modern Stormwater Management Practices on Transport of Road Salt to Surface Waters.

    Science.gov (United States)

    Snodgrass, Joel W; Moore, Joel; Lev, Steven M; Casey, Ryan E; Ownby, David R; Flora, Robert F; Izzo, Grant

    2017-04-18

    Application of road salts in regions with colder climates is leading to ground and surface water contamination. However, we know little about how modern stormwater management practices affect the movement of road salt through urban watersheds. We investigated groundwater contamination and transport of road salts at two stormwater ponds in Baltimore County, Maryland. In association with the ponds, we documented a plume of contaminated groundwater that resulted in Cl - loadings to the adjacent stream of 6574 to 40 008 kg Cl - per winter, depending on winter snowfall. We also monitored Na + and Cl - ion concentrations and the temporal dynamics of conductivity at a range of stream sites in watersheds with and without stormwater management ponds. Streams draining watersheds with stormwater ponds had consistently higher conductivities and Cl - concentrations during base flow conditions and often exhibited greater peaks in Cl - and conductivity associated with winter storms and subsequent melting events, despite the degree of watershed development. Our results indicate that modern stormwater management practices are not protecting surface waters from road salt contamination and suggest they create contaminated plumes of groundwater that deliver Cl - and Na + to streams throughout the year.

  1. A High-Resolution Model of Water Mass Transformation and Transport in the Weddell Sea

    Science.gov (United States)

    Hazel, J.; Stewart, A.

    2016-12-01

    The ocean circulation around the Antarctic margins has a pronounced impact on the global ocean and climate system. One of these impacts includes closing the global meridional overturning circulation (MOC) via formation of dense Antarctic Bottom Water (AABW), which ventilates a large fraction of the subsurface ocean. AABW is also partially composed of modified Circumpolar Deep Water (CDW), a warm, mid-depth water mass whose transport towards the continent has the potential to induce rapid retreat of marine-terminating glaciers. Previous studies suggest that these water mass exchanges may be strongly influenced by high-frequency processes such as downslope gravity currents, tidal flows, and mesoscale/submesoscale eddy transport. However, evaluating the relative contributions of these processes to near-Antarctic water mass transports is hindered by the region's relatively small scales of motion and the logistical difficulties in taking measurements beneath sea ice.In this study we develop a regional model of the Weddell Sea, the largest established source of AABW. The model is forced by an annually-repeating atmospheric state constructed from the Antarctic Mesoscale Prediction System data and by annually-repeating lateral boundary conditions constructed from the Southern Ocean State Estimate. The model incorporates the full Filchner-Ronne cavity and simulates the thermodynamics and dynamics of sea ice. To analyze the role of high-frequency processes in the transport and transformation of water masses, we compute the model's overturning circulation, water mass transformations, and ice sheet basal melt at model horizontal grid resolutions ranging from 1/2 degree to 1/24 degree. We temporally decompose the high-resolution (1/24 degree) model circulation into components due to mean, eddy and tidal flows and discuss the geographical dependence of these processes and their impact on water mass transformation and transport.

  2. Investigation of sediment transport and optimization of dredging operations in Indian ports using radiotracer technique

    International Nuclear Information System (INIS)

    Pant, H.J.

    2012-01-01

    India has a long coastline of about 7,515 km and there are twelve major ports situated on the coastline. Out of them, six are situated on the West Coast whereas other six are situated on the East Coast. In addition to this, there are more than 140 minor ports and other marine establishments situated along the coastline. Each port and marine project has a navigation channel and depth of this navigation channel needs to be maintained to a level of at least 12-15 meters for smooth sailing of ships. Sediments continuously move along the coast due to alongshore currents generated by the waves and tides; and get deposited in navigation channels. For maintaining the required depth of the channels, the dredging operation is carried out. throughout the year or as and when required. Development of a new port or harbour also involves huge capital dredging. The dredged sediments generated during maintenance or capital dredging needs to be dumped at a suitable location, so that it does not find its way back to the channel and obstruct sailing of ships. Moreover the selected site should be such that the turn around time of the dredger is kept minimum to economize the dredging operation. In order to meet the above requirements, the knowledge of transport parameters such as the general direction of movement, extent of lateral and longitudinal movement, transport velocity, transport thickness and bed load movement rate is required. Radiotracer techniques are commonly used to investigate sediment transport on seabed and evaluate the suitability of the proposed dumping sites. Scandium-46 (half-life: 84 days, Gamma energies: 0.89 MeV (100%), 1.12 MeV (100%)) in the form of scandium glass powder is the most suitable radiotracer for tracing sediments on seabed. The activity used in an investigation ranges from 75-300 GBq (2-8 Ci). The suitably prepared particulate radiotracer is injected on seabed at the proposed site using a specially designed injection system and its movement is

  3. Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kandlikar, Satish G. [Rochester Inst. of Technology, Rochester, NY (United States); Lu, Zijie [Rochester Inst. of Technology, Rochester, NY (United States); Rao, Navalgund [Rochester Inst. of Technology, Rochester, NY (United States); Sergi, Jacqueline [Rochester Inst. of Technology, Rochester, NY (United States); Rath, Cody [Rochester Inst. of Technology, Rochester, NY (United States); McDade, Christopher [Rochester Inst. of Technology, Rochester, NY (United States); Trabold, Thomas [General Motors, Honeoye Falls, NY (United States); Owejan, Jon [General Motors, Honeoye Falls, NY (United States); Gagliardo, Jeffrey [General Motors, Honeoye Falls, NY (United States); Allen, Jeffrey [Michigan Technological Univ., Houghton, MI (United States); Yassar, Reza S. [Michigan Technological Univ., Houghton, MI (United States); Medici, Ezequiel [Michigan Technological Univ., Houghton, MI (United States); Herescu, Alexandru [Michigan Technological Univ., Houghton, MI (United States)

    2010-05-30

    In this program, Rochester Institute of Technology (RIT), General Motors (GM) and Michigan Technological University (MTU) have focused on fundamental studies that address water transport, accumulation and mitigation processes in the gas diffusion layer and flow field channels of the bipolar plate. These studies have been conducted with a particular emphasis on understanding the key transport phenomena which control fuel cell operation under freezing conditions.

  4. Investigating bomb radiocarbon transport in the southern Pacific Ocean with otolith radiocarbon

    Science.gov (United States)

    Grammer, G. L.; Fallon, S. J.; Izzo, C.; Wood, R.; Gillanders, B. M.

    2015-08-01

    To explore the transport of carbon into water masses from the surface ocean to depths of ∼ 1000 m in the southwest Pacific Ocean, we generated time series of radiocarbon (Δ14C) from fish otoliths. Otoliths (carbonate earstones) from long-lived fish provide an indirect method to examine the "bomb pulse" of radiocarbon that originated in the 1950s and 1960s, allowing identification of changes to distributions of 14C that has entered and mixed within the ocean. We micro-sampled ocean perch (Helicolenus barathri) otoliths, collected at ∼ 400- 500 m in the Tasman Sea, to obtain measurements of Δ14C for those depths. We compared our ocean perch Δ14C series to published otolith-based marine surface water Δ14C values (Australasian snapper (Chrysophrys auratus) and nannygai (Centroberyx affinis)) and to published deep-water values (800-1000 m; orange roughy (Hoplostethus atlanticus)) from the southwest Pacific to establish a mid-water Δ14C series. The otolith bomb 14C results from these different depths were consistent with previous water mass results in the upper 1500 m of the southwest Pacific Ocean (e.g. World Ocean Circulation Experiment and Geochemical Ocean Sections Study). A comparison between the initial Δ14C bomb pulse rise at 400-500 m suggested a ventilation lag of 5 to 10 yr, whereas a comparison of the surface and depths of 800-1000 m detailed a 10 to 20 yr lag in the time history of radiocarbon invasion at this depth. Pre-bomb reservoir ages derived from otolith 14C located in Tasman Sea thermocline waters were ∼ 530 yr, while reservoir ages estimated for Tasman Antarctic intermediate water were ∼ 730 yr.

  5. Fate and transport of oil sand process-affected water into the underlying clay till: A field study

    Science.gov (United States)

    Abolfazlzadehdoshanbehbazari, Mostafa; Birks, S. Jean; Moncur, Michael C.; Ulrich, Ania C.

    2013-08-01

    The South Tailings Pond (STP) is a ~ 2300-ha tailing pond operated by Suncor Energy Inc. that has received oil sand process-affected (PA) water and mature fine tailings since 2006. The STP is underlain by a clay till, which is in turn underlain by the Wood Creek Sand Channel (WCSC). The sandy deposits of the WCSC provide greater geotechnical stability but could act as a potential flow pathway for PA water to migrate off site and into the Athabasca River. Preliminary modeling of the STP suggests that PA water from the pond will infiltrate into the underlying sand channel, but the extent and development of this impact is still poorly understood. Suncor Energy Inc. built interception wells and a cut-off-wall to control any potential seepage. Here we present the results of an investigation of the fate and transport of PA water in clay till underlying a 10 m × 10 m infiltration pond that was constructed on the southeastern portion of the STP. The geochemistry of pore water in the till underlying the infiltration pond was determined prior to filling with process-affected water (2008) and two years after the infiltration pond was filled with PA waters (2010). Pore water was analyzed for metals, cations, anions, and isotopes (2H and 18O). The distribution of conservative tracers (18O and chloride) indicated migration of the PA waters to approximately 0.9 m, but the migrations of major ions and metals were significantly delayed relative to this depth. Uptake of Na and Mo and release of Ca, Mg, Mn, Ba, and Sr suggest that adsorption and ion exchange reactions are the foremost attenuation processes controlling inorganic solutes transport.

  6. Investigation of Electromagnetic Field Threat to Fuel Tank Wiring of a Transport Aircraft

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Dudley, Kenneth L.; Scearce, Stephen A.; Beck, Fred B.; Deshpande, Manohar D.; Cockrell, C. R.

    2000-01-01

    National Transportation Safety Board investigators have questioned whether an electrical discharge in the Fuel Quantity Indication System (FQIS) may have initiated the TWA-800 center wing tank explosion. Because the FQIS was designed to be incapable of producing such a discharge on its own, attention has been directed to mechanisms of outside electromagnetic influence. To support the investigation, the NASA Langley Research Center was tasked to study the potential for radiated electromagnetic fields from external radio frequency (RF) transmitters and passenger carried portable electronic devices (PEDs) to excite the FQIS enough to cause arcing, sparking or excessive heating within the fuel tank.

  7. Analysis of the sodium recirculation theory of solute-coupled water transport in small intestine.

    Science.gov (United States)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkaer

    2002-07-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+-2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral flows of water across the epithelium with recirculation of the diffusible ions maintained by a 1Na+-1K+-2Cl- cotransporter in the plasma membrane facing the serosal compartment. With intracellular non-diffusible anions and compliant plasma membranes, the model describes the dependence on membrane permeabilities and pump constants of fluxes of water and electrolytes, volumes and ion concentrations of cell and lateral intercellular space (lis), and membrane potentials and conductances. Simulating physiological bioelectrical features together with cellular and paracellular fluxes of the sodium ion, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions. The computed sodium recirculation flux that is required for isotonic transport corresponds to that estimated in experiments on toad small intestine. This result is shown to be robust and independent of whether the apical entrance mechanism for the sodium ion is a channel, a SGLT1 transporter driving inward uphill water flux, or an electroneutral Na+-K+-2Cl- cotransporter.

  8. Do Transport Infrastructures Promote the Foreign Direct Investments Attractiveness? Empirical Investigation from Four North African Countries

    Directory of Open Access Journals (Sweden)

    Samir Saidi

    2018-03-01

    Full Text Available The relationship among foreign direct investments and economic growth is a very controversial issue that has given rise to an abundant literature. Numerous research studies examine the bidirectional causal relationship and investigate the major determinants of these investments. In the same order of ideas, this article gives an empirical study from four North African countries to evaluate the role of transport infrastructures to improve the territorial attractiveness for the foreign direct investment. The present paper starts by a theoretical study explaining the role of transport as a major determinant of FDI. In a second section, we represent the empirical study. By using an econometric model with panel data, we found that traditional determinants of FDI have the most significant influence on the international investors’ decision. However, the same findings verify a positive impact of transport and consider it as a new important factor with strategic issues that cannot be avoided. The empirical validation from the four countries leads to verify that it is necessary to adopt development strategies that take into account the transport infrastructures and logistics function

  9. Experimental and gyrokinetic investigation of core impurity transport in Alcator C-mod

    Science.gov (United States)

    Howard, N.; Greenwald, M.; Podpaly, Y.; Reinke, M. L.; Rice, J. E.; White, A. E.; Mikkelsen, D. R.; Puetterich, T.

    2010-11-01

    A new multiple pulse laser blow-off system coupled with an upgraded high resolution x-ray spectrometer with spatial resolution allow for the most detailed studies of impurity transport on Alcator C-mod to date. Trace impurity injections created by the laser blow-off technique were introduced into plasmas with a wide range of parameters and time evolving profiles of He-like calcium were measured. The unique measurement of a single charge state profile and line integrated emission measurements from spectroscopic diagnostics were compared with the simulated emission from the impurity transport code STRAHL. A nonlinear least squares fitting routine was coupled with STRAHL, allowing for core impurity transport coefficients with errors to be determined. With this method, experimental data from trace calcium injections were analyzed and radially dependent, core values (< r/a ˜.6) of the diffusive and convective components of the impurity flux were obtained. The STRAHL results are compared with linear and global, nonlinear simulations from the gyrokinetic code GYRO. Results of this comparison and an investigation of the underlying physics associated with turbulent impurity transport will be presented.

  10. Reforming the road freight transportation system using systems thinking: An investigation of Coronial inquests in Australia.

    Science.gov (United States)

    Newnam, Sharon; Goode, Natassia; Salmon, Paul; Stevenson, Mark

    2017-04-01

    Road freight transport is considered to be one of the most dangerous industries in Australia, accounting for over 30% of all work fatalities. Whilst system reform (i.e., change to policy and practice) is needed, it is not clear what this reform should be, or what approaches should be used to drive it. This article argues that road freight transportation reform should be underpinned by a systems thinking approach. Efforts to understand crash causation should be focused beyond the driver and identify contributing factors at other levels with the road freight system. Accordingly, we present the findings from a study that examined whether Australian Coronial investigations into road freight crashes reflect support appropriate system reform. Content analysis was used to identify the contributing factors and interrelations implicated in the road freight crashes described in publicly available Australian Coroner's inquest reports from the last 10 years (2004-2014; n=21). The results found evidence to suggest that the Coronial inquests provide some understanding of the complex system of factors influencing road freight transportation crashes in Australia. However, there was a lack of evidence to suggest an understanding of system-based reform based on the identification of reductionist-focused recommendations. It is concluded that researchers and practitioners (ie., government and industry) need to work together to develop prevention efforts focused on system reforms. Systems thinking based data collection and analysis frameworks are urgently required to help develop this understanding in road freight transportation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A dispersion model of transport media in radiotracer investigations on selected chemical installations

    International Nuclear Information System (INIS)

    Iller, E.

    1999-01-01

    Tracer investigations of media transport through chemical reactors play a significant role in the chemical technology. They provide the basis for the determination of some important process parameters, such as flow character of the transported medium, degree of utilisation of the reactor volume during chemical transitions of substrates or even indicate possible mechanisms of chemical reactions. Determination of the medium flow characteristics is closely connected with the mathematical description of the process - a mathematical model of transport. The method of assessment of radiotracers suitability for the investigation of distillation processes presented in this paper allows to determine, in a simple manner, the parameters of distillation characteristics of the radionuclides, the average distillation temperature, the range of distillation temperatures, a suitable radiochemical purity. These parameters precisely determine the behavior of tracers to be expected in a wide range of variable conditions of the distillation process. Applications of tracer tested in such a manner to the investigations of dynamics of media in the industrial rectification columns has resulted in obtaining a dependable evaluation of the performance of these columns in a wide range of changes of their operational parameters. Particular attention has been paid to dynamics of the liquid [phase on the column plate. A dispersion model of liquid flow with hold-up zones has been proposed for the description of the liquid phase transport in the plate - overall assembly.The model consists of a number of flow and stagnant zones, with mass transfer between them. Another example of practical application of results from radiotracer investigation is an analysis of of phase dynamics in the installations designed for the process of liquefaction of Polish coals by means of their catalytic hydrogenation. For the analysis of phase transport in a reaction vessel various mathematical models were applied with

  12. Water transport through cement-based barriers-A preliminary study using neutron radiography and tomography

    Energy Technology Data Exchange (ETDEWEB)

    Brew, D.R.M. [ANSTO (Australian Nuclear Science and Technology Organisation), Menai, NSW 2234 (Australia)], E-mail: dbr@ansto.gov.au; Beer, F.C. de; Radebe, M.J.; Nshimirimana, R. [Necsa (South African Nuclear Energy Corporation), Pretoria (South Africa); McGlinn, P.J.; Aldridge, L.P.; Payne, T.E. [ANSTO (Australian Nuclear Science and Technology Organisation), Menai, NSW 2234 (Australia)

    2009-06-21

    In this preliminary study we use neutron radiography and tomography to examine differences in water transport through cement pastes and mortars. Bulk residual water contents and sorptivity curves determined using neutron radiography are compared with data obtained gravimetrically. In addition, macro-pore volume distributions of each sample were measured. Furthermore, it was possible to use neutron radiography to monitor the change in the mass of water when samples were dried or when water moved into the samples. The trends and absolute values of weight loss and gain obtained using both approaches are very consistent for mortars, especially when a neutron-scattering correction is applied.

  13. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B.; Hunter, R.L.; Pickens, J.F.

    1991-01-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The U.S. Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. Computer code used: SWIFT II (flow and transport code). 4 figs., 12 refs

  14. Transport properties of water molecules confined between hydroxyapaptite surfaces: A Molecular dynamics simulation approach

    Science.gov (United States)

    Prakash, Muthuramalingam; Lemaire, Thibault; Di Tommaso, Devis; de Leeuw, Nora; Lewerenz, Marius; Caruel, Matthieu; Naili, Salah

    2017-10-01

    Water diffusion in the vicinity of hydroxyapatite (HAP) crystals is a key issue to describe biomineralization process. In this study, a configuration of parallel HAP platelets mimicking bone nanopores is proposed to characterize the nanoscopic transport properties of water molecules at HAP-water surface and interfaces using various potential models such as combination of the Core-Shell (CS) model, Lennard-Jones (LJ) potentials with SPC or SPC/E water models. When comparing all these potentials models, it appears that the core-shell potential for HAP together with the SPC/E water model more accurately predicts the diffusion properties of water near HAP surface. Moreover, we have been able to put into relief the possibility of observing hydroxyl (OH-) ion dissociation that modifies the water structure near the HAP surface.

  15. Investigation on processing technology for tritiated water in glove box

    International Nuclear Information System (INIS)

    Luo Deli; Meng Daqiao

    2002-01-01

    A 0.5 nm molecular sieve absorption column and a hot decomposing magnesium bed was found to be one of the effective means to collect and decompose HTO in glove box atmosphere. The absorption characteristics of the 0.5 nm molecular sieve column and water decomposing characteristics of the hot Mg bed were obtained. The results showed that the column absorbs water vapour from air with efficiency up to 99.99%. Water in tested gases was between 3.4 x 10 3 to 4.2 x 10 3 μg·g -1 and the total water absorbed on the column was up to 162 g, under this condition no water was detected in output gases. Using the hot magnesium bed more than 99.9% desorption water from the column was decomposed

  16. A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

    2000-01-01

    those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio of the solute (influx/outflux) is small (2-4) in agreement with experiments. The virtual solute...... concentration of fluid emerging from lis is then significantly larger than the concentration in lis. Thus, in absence of external driving forces the model generates isotonic transport provided a component of the solute flux emerging downstream lis is taken up by cells through the serosal membrane and pumped...

  17. Large-scale Experiment for Water and Gas Transport in Cementitious Backfill Materials (Phase 1 ): COLEX I

    International Nuclear Information System (INIS)

    Mayer, G.; Wittmann, F.H.; Moetsch, H.A.

    1998-05-01

    In the planned Swiss repository for low- and intermediate-level radioactive waste, the voids between the waste containers will be backfilled with a highly permeable mortar (NAGRA designation: mortar M1 ). As well as providing mechanical stability through filling of voids and sorbing radionuclides, the mortar must divert gases formed in the repository as a result of corrosion into the neighbouring host rock. This will prevent damage which could be caused by excess pressure on the repository structures. Water transport, which is coupled to gas transport, is also of interest. The former is responsible for the migration of radionuclides. Up till now, numerical simulations for a repository situation were carried out using transport parameters determined for small samples in the laboratory. However, the numerical simulations still had to be validated by a large-scale experiment. The investigations presented here should close this gap. Investigations into gas and water transport were carried out using a column (up to 5.4 m high) filled with backfill mortar. The column has a modular construction and can be sealed at the top end with a material of defined permeability (plug or top plug). The possibility to vary the material of the plug allows the influence of the more impermeable cavern lining or possible gas escape vents in the cavern roof to be investigated. A gas supply is connected to the bottom end and is used to simulate different gas generation rates from the waste. A total of 5 experiments were carried out in which the gas generation rate, the column height and the permeability of the plug were varied. Before the start of the experiments, the mortar in the column and the plug were saturated with water to approx. 95 %. In all the experiments, an increase in pressure with time could be observed. The higher the gas generation rate and the lower the permeability of the plug, the more quickly this occurred. At the beginning, only water flow out of the top of the column

  18. Radiotracer investigations in oil production and water injection wells

    International Nuclear Information System (INIS)

    Eapen, A.C.; Jain, S.K.; Kirti

    1977-01-01

    Injection of gamma emitting radiotracers into oil wells followed by logging provides information on several aspects such as the identification of zones of seepage of water in the water injection wells and also the location of source of water entering oil producting wells. The experience gained in the application of bromine-82 and rubidium-86 as radiotracers in such studies at the Ankleshwar and Kalol oil fields in Gujarat and Nazira in Assam has been briefly reported. (author)

  19. Investigation of the dimensionality of charge transport in organic field effect transistors

    Science.gov (United States)

    Abdalla, Hassan; Fabiano, Simone; Kemerink, Martijn

    2017-02-01

    Ever since the first experimental investigations of organic field effect transistors (OFETs) the dimensionality of charge transport has alternately been described as two dimensional (2D) and three dimensional (3D). More recently, researchers have turned to an analytical analysis of the temperature-dependent transfer characteristics to classify the dimensionality as either 2D or 3D as well as to determine the disorder of the system, thereby greatly simplifying dimensionality investigations. We applied said analytical analysis to the experimental results of our OFETs comprising molecularly well-defined polymeric layers as the active material as well as to results obtained from kinetic Monte Carlo simulations and found that it was not able to correctly distinguish between 2D and 3D transports or give meaningful values for the disorder and should only be used for quasiquantitative and comparative analysis. We conclude to show that the dimensionality of charge transport in OFETs is a function of the interplay between transistor physics and morphology of the organic material.

  20. Analytical and experimental investigations of the passive heat transport in HTRs under severe accident conditions

    International Nuclear Information System (INIS)

    Rehm, W.; Barthels, H.; Jahn, W.; Cleveland, J.C.; Ishihara, M.

    1992-01-01

    Thermodynamic accident analyses have been performed with computer simulation models to investigate core heatup sequences, sensitivity analyses, power variations, anticipated transients without scram, and core displacement considerations for probabilistic safety analyses (PSA) of small gas-cooled high-temperature reactors (e.g. HTR-Module). In worst case considerations where not only a loss of the active heat removal system is assumed but also a loss of the vessel cooling system, the heat would be transported into the surrounding concrete structure. In such a case the concrete would act as a natural long-term intermediate heat storage dissipating the heat through the concrete surface. Large scale and reactor safety experiments have been performed to investigate passive heat transport mechanisms -- which can cooldown a HIR core during severe accident conditions -- for validation basis of computer simulation codes used for accident analyses. In general, the comparisons of experimental and analytical results with computer calculations of the heat transport codes are in good agreement

  1. Breviscapine prevents downregulation of renal water and sodium transport proteins in response to unilateral ureteral obstruction

    Directory of Open Access Journals (Sweden)

    Yang Mei

    2016-05-01

    Full Text Available Objective(s:Our recent report indicates that breviscapine play a protective role of the kidney by down-regulating transforming growth factor-β1(TGF-β1, α-smooth muscle actin (α-SMA and alleviating interstitial fibrosis following unilateral ureteral obstruction (UUO. In this study, we investigate the effect of breviscapine on changes of renal water and sodium transport proteins in response to UUO. Materials and Methods: Male Sprague-Dawley rats were divided into 3 groups, sham group, UUO group and UUO treat with breviscapine. After 4, 7 and 14 days, histologic changes and interstitial collagen were determined microscopically following hematoxylin and eosin (H&E and Masson's trichrome staining. The expression of Aquaporins (AQP-2 and γ-epithelial sodium channel (γ-ENaC were investigated using immunohistochemistry and Western blot in each group. Results:Breviscapine treatment decrease the tubular injury index and the degree of interstitial collagen deposition significantly compared with the UUO group (P

  2. Impacts of Cropland Changes on Water Balance, Sediment and Nutrient Transport in Eden River, UK

    Science.gov (United States)

    Huang, Yumei; Quinn, Paul; Liang, Qiuhua; Adams, Russell

    2017-04-01

    Water is the key to food and human life. Farming is the main part of economic and society in Eden, with approximately 2000 farms which covers 95% of under crops. However, with the growth of farming practice and global climate changes, Eden has presented great challenges and bringing uncertainty in the water quality caused by the agricultural diffuse pollution. This expected to reduce negative impacts of the water diffuse pollution from agriculture in Eden. Therefore, there is a high need to ensure effective water resource management to enhance water quality, to address the flow pathways and sediment transport in different farming practice and cropland changes. Hence we need to understand nutrient and the hydrological flow pathways from soil to Hillslope to channel. The aim of this research is to evaluate the impacts of different cropland changes on water balance, sediment and nutrient transport. By using the hydrological models Soil and Water Assessment Tool (SWAT) and the Catchment Runoff Attenuation Flux Tool (CRAFT), it can show the sediment and nutrient export from the load for each flow pathways (overland flow, soil water flow and ground water flow). We will show results from a small research catchment (10km2) area to the whole of Eden (800km2) at a daily time step.

  3. Agricultural phosphorus and water quality: sources, transport and management

    Directory of Open Access Journals (Sweden)

    A. SHARPLEY

    2008-12-01

    Full Text Available Freshwater eutrophication is usually controlled by inputs of phosphorus (P. To identify critical sources of P export from agricultural catchments we investigated hydrological and chemical factors controlling P export from a mixed land use (30% wooded, 50% cultivated, 20% pasture 39.5-ha catchment in east-central Pennsylvania, USA. Mehlich-3 extractable soil P, determined on a 30-m grid over the catchment, ranged from 7 to 788 mg kg-1. Generally, soils in wooded areas had low Mehlich-3 P (

  4. Numerical investigation of interfacial mass transport resistance and two-phase flow in PEM fuel cell air channels

    Science.gov (United States)

    Koz, Mustafa

    Proton exchange membrane fuel cells (PEMFCs) are efficient and environmentally friendly electrochemical engines. The performance of a PEMFC is adversely affected by oxygen (O2) concentration loss from the air flow channel to the cathode catalyst layer (CL). Oxygen transport resistance at the gas diffusion layer (GDL) and air channel interface is a non-negligible component of the O2 concentration loss. Simplified PEMFC performance models in the available literature incorporate the O2 resistance at the GDL-channel interface as an input parameter. However, this parameter has been taken as a constant so far in the available literature and does not reflect variable PEMFC operating conditions and the effect of two-phase flow in the channels. This study numerically calculates the O2 transport resistance at the GDL-air channel interface and expresses this resistance through the non-dimensional Sherwood number (Sh). Local Sh is investigated in an air channel with multiple droplets and films inside. These water features are represented as solid obstructions and only air flow is simulated. Local variations of Sh in the flow direction are obtained as a function of superficial air velocity, water feature size, and uniform spacing between water features. These variations are expressed with mathematical expressions for the PEMFC performance models to utilize and save computational resources. The resulting mathematical correlations for Sh can be utilized in PEMFC performance models. These models can predict cell performance more accurately with the help of the results of this work. Moreover, PEMFC performance models do not need to use a look-up table since the results were expressed through correlations. Performance models can be kept simplified although their predictions will become more realistic. Since two-phase flow in channels is experienced mostly at lower temperatures, performance optimization at low temperatures can be done easier.

  5. Nutrient transport in the mammary gland: calcium, trace minerals and water soluble vitamins.

    Science.gov (United States)

    Montalbetti, Nicolas; Dalghi, Marianela G; Albrecht, Christiane; Hediger, Matthias A

    2014-03-01

    Milk nutrients are secreted by epithelial cells in the alveoli of the mammary gland by several complex and highly coordinated systems. Many of these nutrients are transported from the blood to the milk via transcellular pathways that involve the concerted activity of transport proteins on the apical and basolateral membranes of mammary epithelial cells. In this review, we focus on transport mechanisms that contribute to the secretion of calcium, trace minerals and water soluble vitamins into milk with particular focus on the role of transporters of the SLC series as well as calcium transport proteins (ion channels and pumps). Numerous members of the SLC family are involved in the regulation of essential nutrients in the milk, such as the divalent metal transporter-1 (SLC11A2), ferroportin-1 (SLC40A1) and the copper transporter CTR1 (SLC31A1). A deeper understanding of the physiology and pathophysiology of these transporters will be of great value for drug discovery and treatment of breast diseases.

  6. Experimental investigation of turbulent transport at the edge of a tokamak plasma

    International Nuclear Information System (INIS)

    Fedorczak, N.

    2010-01-01

    This manuscript is devoted to the experimental investigation of particle transport in the edge region of the tokamak Tore Supra. The first part introduces the motivations linked to energy production, the principle of a magnetic confinement and the elements of physics essential to describe the dynamic of the plasma at the edge region. From data collected by a set of Langmuir probes and a fast visible imaging camera, we demonstrate that the particle transport is dominated by the convection of plasma filaments, structures elongated along magnetic field lines. They present a finite wave number, responsible for the high enhancement of the particle flux at the low field side of the tokamak. This leads to the generation of strong parallel flows, and the strong constraint of filament geometry by the magnetic shear. (author)

  7. Technical note An investigation of the franchising option for water ...

    African Journals Online (AJOL)

    of the operation of water services, and outlines the need to formulate a franchise model that could be developed and made available to emerging entrepreneurs as the basis of a viable business. The franchising would be in respect of components of the water services value chain that are suitable for small businesses in that ...

  8. investigation of factors affecting drinking water quality from source

    African Journals Online (AJOL)

    user

    storage container by pouring showed a significant reduction on the concentration of faecal coliform than dipping (P<0.05). A similar study in Bolivia indicated that. 52.0% of the respondents admitted that they had introduced their hands into drinking water stored in the house, which results in the contamination of stored water.

  9. Investigating the effects of water vaporization on the production of ...

    African Journals Online (AJOL)

    The simulations show that water vaporization increases productivity of well by increasing gas saturation and relative permeability near the well walls and improving the mobility of gas; and this effect is stronger in rich gas condensate reservoir than the lean ones. Keywords: Well, Gas, Pressure Drop, Vapor pressure of water ...

  10. Investigation of heat transfer for extruded polymers cooled in water

    CSIR Research Space (South Africa)

    Kumar, R

    2015-10-01

    Full Text Available to be extruded before they are fabricated for end users. The work described in this paper has been divided in two parts. In the first part PE, PP and PLA are subjected to extrusion and the extruded polymers are allowed to pass in a water bath having still water...

  11. Investigation of Different Water Sources as a Possible Cause of ...

    African Journals Online (AJOL)

    Vibrio cholerae, 01 serogroup, Ogawa serotype and EI-Tor biotype was isolated from 20.8% of the water samples tested. These isolates showed multiple resistance to antibiotics particularly tetracycline but were susceptible to the cephalosporins. Eleven other water samples (45.8%) showed growth of Enterococcus faecalis ...

  12. Transport and transfer rates in the waters of the continental shelf. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Biscaye, P.E.

    1980-09-01

    The goal of govern project is to understand and quantify the processes that the transport and dispersal of energy-related pollutants introduced to the waters of the continental shelf and slope. The report is divided into sections dealing with processes associated with suspended solids; processes associated with sediments sinks for radionuclides and other pollutants; and spreading of water characteristics and species in solution. (ACR)

  13. USGS investigations of water produced during hydrocarbon reservoir development

    Science.gov (United States)

    Engle, Mark A.; Cozzarelli, Isabelle M.; Smith, Bruce D.

    2014-01-01

    Significant quantities of water are present in hydrocarbon reservoirs. When brought to the land surface during oil, gas, and coalbed methane production, the water—either naturally occurring or injected as a method to enhance production—is termed produced water. Produced water is currently managed through processes such as recycling, treatment and discharge, spreading on roads, evaporation or infiltration, and deep well injection. U.S. Geological Survey (USGS) scientists conduct research and publish data related to produced water, thus providing information and insight to scientists, decisionmakers, the energy industry, and the public. The information advances scientific knowledge, informs resource management decisions, and facilitates environmental protection. This fact sheet discusses integrated research being conducted by USGS scientists supported by programs in the Energy and Minerals and Environmental Health Mission Areas. The research products help inform decisions pertaining to understanding the nature and management of produced water in the United States.

  14. Investigation of DMSD Trend in the ISS Water Processor Assembly

    Science.gov (United States)

    Carter, Layne; Bowman, Elizabeth; Wilson, Mark; Gentry, Greg; Rector, Tony

    2013-01-01

    The ISS Water Recovery System (WRS) is responsible for providing potable water to the crew, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. The WRS includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WPA processes condensate from the cabin air and distillate produced by the UPA. In 2010, an increasing trend in the Total Organic Carbon (TOC) in the potable water was ultimately identified as dimethylsilanediol (DMSD). The increasing trend was ultimately reversed after replacing the WPA's two multifiltration beds. However, the reason for the TOC trend and the subsequent recovery was not understood. A subsequent trend occurred in 2012. This paper summarizes the current understanding of the fate of DMSD in the WPA, how the increasing TOC trend occurred, and the plan for modifying the WPA to prevent recurrence.

  15. ICON-ART-ISO: Water isotopologues implemented in the chemistry- transport model ICON-ART

    Science.gov (United States)

    Eckstein, Johannes; Ruhnke, Roland; Reinert, Daniel; Pfahl, Stephan

    2017-04-01

    Stable isotopes of water can help to understand processes that have influenced the distribution of water in the atmosphere. Isotope enabled models, capable of simulating the distribution of HDO and H218O, can be a very useful tool for understanding these processes and the distribution of isotope ratios which are observed. We present ICON-ART-ISO, the implementation of water isotopes into the chemistry-transport model ICON-ART. The core of this global model is the ICOsahedral Non-hydrostatic (ICON) modelling framework (Zaengl et al, 2015 (Q. J. R. Meteorol. Soc.)), a joint development of the German Weather Service (DWD) and the Max Planck Institute for Meteorology. The model system ICON-ART (Aerosols and Reactive Trace gases, Rieger et al, 2015 (GMD)) is a two-way coupled extension to ICON, which allows to study the influence of aerosols, trace gases and their chemistry on the atmosphere. We set up ICON-ART-ISO within this framework, profitting from the model infrastructure. We follow the implementation of COSMOiso (Pfahl et al., 2012 (ACP)), the isotope-enabled version of the COSMO model, the predecessor of ICON. In order to include the isotopes in the model, the water cycle is doubled diagnostically for each isotope. By the choice of physical parameters, these modelled isotopes are set to HDO and H218O, but the simulation of a purely diagnostic H2O is also possible. Fractionation, i.e. the change of the isotope ratio changes during phase changes, is considered in evaporation, grid-scale precipitation and convection. For the source of evaporation, a constant isotope ratio is currently used. To consider grid scale precipitation, the processes in the two-moment microphysical scheme by Seifert and Beheng, 2005 (Meteorol. Atmos. Phys.) are diagnostically applied to the isotopes. For convection, the Tiedtke-Bechtold scheme (Bechtold et al., 2013 (JAS)) is used. We present the current status of the model system. All processes have been implemented and we show first

  16. Prolonged river water pollution due to variable-density flow and solute transport in the riverbed

    Science.gov (United States)

    Jin, Guangqiu; Tang, Hongwu; Li, Ling; Barry, D. A.

    2015-04-01

    A laboratory experiment and numerical modeling were used to examine effects of density gradients on hyporheic flow and solute transport under the condition of a solute pulse input to a river with regular bed forms. Relatively low-density gradients due to an initial salt pulse concentration of 1.55 kg m-3 applied in the experiment were found to modulate significantly the pore-water flow and solute transport in the riverbed. Such density gradients increased downward flow and solute transport in the riverbed by factors up to 1.6. This resulted in a 12.2% increase in the total salt transfer from the water column to the riverbed over the salt pulse period. As the solute pulse passed, the effect of the density gradients reversed, slowing down the release of the solute back to the river water by a factor of 3.7. Numerical modeling indicated that these density effects intensified as salt concentrations in the water column increased. Simulations further showed that the density gradients might even lead to unstable flow and result in solute fingers in the bed of large bed forms. The slow release of solute from the bed back to the river led to a long tail of solute concentration in the river water. These findings have implications for assessment of impact of pollution events on river systems, in particular, long-term effects on both the river water and riverbed due to the hyporheic exchange.

  17. Water transport and clustering behavior in homopolymer and graft copolymer polylactide

    Energy Technology Data Exchange (ETDEWEB)

    Du, An; Koo, Donghun; Theryo, Grayce; Hillmyer, Marc A.; Cairncross, Richard A. (Drexel); (UMM)

    2015-02-19

    Polylactide is a bio-based and biodegradable polymer well-known for its renewable origins. Water sorption and clustering behavior in both a homopolymer polylactide and a graft copolymer of polylactide was studied using the quartz crystal microbalance/heat conduction calorimetry (QCM/HCC) technique. The graft copolymer, poly(1,5-cyclooctadiene-co-5-norbornene-2-methanol-graft-D,L-lactide), contained polylactide chains (95 wt.%) grafted onto a hydrophobic rubbery backbone (5 wt.%). Clustering is an important phenomenon in the study of water transport properties in polymers since the presence of water clusters can affect the water diffusivity. The HCC method using the thermal power signals and Van't Hoff's law were both employed to estimate the water sorption enthalpy. Sorption enthalpy of water in both polymers was determined to be approximately -40 kJ/mol for all water activity levels. Zimm-Lundberg analysis showed that water clusters start to form at a water activity of 0.4. The engaged species induced clustering (ENSIC) model was used to curve fit sorption isotherms and showed that the affinity among water molecules is higher than that between water molecules and polymer chains. All the methods used indicate that clustering of water molecules exists in both polymers.

  18. Water and Solute Transport in Arid Vadose Zones: Innovations in Measurement and Analysis

    International Nuclear Information System (INIS)

    Tyler, S W.; Scanlon, Bridget R.; Gee, Glendon W.; Allison, G B.; Parlange, M. B.; Hopmans, J. W.

    1999-01-01

    Understanding the physics of flow and transport through the vadose zone has advanced significantly in the last three decades. These advances have been made primarily in humid regions or in irrigated agricultural settings. While some of the techniques are useful, many are not suited to arid regions. The fluxes of water and solutes typically found in arid regions are often orders of magnitude smaller than those found in agricultural settings, while the time scales for transport can be orders of magnitude larger. The depth over which transport must be characterized is also often much greater than in humid regions. Rather than relying on advances in applied tracers, arid-zone researchers have developed natural tracer techniques that are capable of quantifying transport over tens to thousands of years. Techniques have been developed to measure the hydraulic properties of sediments at all water contents, including the very dry range and at far greater depths. As arid and semiarid regions come under increased development pressures for such activities as hazardous- and radioactive-waste disposal, the development of techniques and the understanding of water and solute transport have become crucial components in defining the environmental impacts of activities at the landsurface

  19. Continuous directional water transport on the peristome surface of Nepenthes alata

    Science.gov (United States)

    Chen, Huawei; Zhang, Pengfei; Zhang, Liwen; Liu, Hongliang; Jiang, Ying; Zhang, Deyuan; Han, Zhiwu; Jiang, Lei

    2016-04-01

    Numerous natural systems contain surfaces or threads that enable directional water transport. This behaviour is usually ascribed to hierarchical structural features at the microscale and nanoscale, with gradients in surface energy and gradients in Laplace pressure thought to be the main driving forces. Here we study the prey-trapping pitcher organs of the carnivorous plant Nepenthes alata. We find that continuous, directional water transport occurs on the surface of the ‘peristome’—the rim of the pitcher—because of its multiscale structure, which optimizes and enhances capillary rise in the transport direction, and prevents backflow by pinning in place any water front that is moving in the reverse direction. This results not only in unidirectional flow despite the absence of any surface-energy gradient, but also in a transport speed that is much higher than previously thought. We anticipate that the basic ‘design’ principles underlying this behaviour could be used to develop artificial fluid-transport systems with practical applications.

  20. On the water transport of animals with special reference to Denmark.

    Science.gov (United States)

    Katić, Ivan; Bajt, Vesna Vucevac

    2009-01-01

    Transport of animals by water is a very old way of transport because it is relatively cheap and safe, with a minimum loss of animals. Waterways have been used for the transport of living animals and various goods from ancient times, for example in Ancient Egypt and the Roman Empire. Later, Vikings were so successful in their conquests because they always had trained horses aboard. It is believed that the colonization of America was possible because Spaniards were also bringing many horses with them. Danish possessions in the Caribbean owe much of their economic success in the period between 1820 and 1920 to permanent supply of cheap mules and other equides from South America. Mules were used for agricultural purposes and for work in sugar-cane mills. In the 20th century, a significant number of animals was transported to German and British colonies in South Africa. During the First and the Second World War, animals were also transported by water; measures were taken to meet the fundamental physiological requirements, and a veterinarian accompanied animals on long voyages. These precautions resulted in minimum transport losses.

  1. The establishment of Atlantic Water transport as a topographically trapped slope current off Scotland

    Directory of Open Access Journals (Sweden)

    Qin Zhou

    2013-05-01

    Full Text Available Atlantic Water, with its origin in the western Atlantic, enters the Nordic Seas partly as a barotropic current following the continental slope. This water mass is carried across the Atlantic by the baroclinic North Atlantic Current (NAC. When the NAC meets the continental slope at the east side of the Atlantic, some of the transport is converted to barotropic transport over the slope before continuing northward. Here, we show that this baroclinic to barotropic conversion is in agreement with geostrophic theory. Historical observations show that the transport of the slope current increases significantly from the Rockall Channel (RC to the Faroe–Shetland Channel (FSC. Geostrophy predicts that with a northward decreasing buoyancy, baroclinic currents from the west will be transferred into northward topographically steered barotropic flow. We use hydrographic data from two sections crossing the continental slope, one located in the RC and another in the FSC, to estimate baroclinic and barotropic transport changes over the slope, within the framework of geostrophic dynamics. Our results indicate that ~1 Sv of the cross-slope baroclinic flow is mainly converted to northward barotropic transport above the 200–500m isobaths, which is consistent with observed transport changes between the RC and the FSC. Similar processes are also likely to occur further south, along the eastern Atlantic margin. This shows that AW within the slope current in the FSC is derived from both the eastern and the western Atlantic, in agreement with earlier studies of AW inflow to the Nordic Seas.

  2. Investigating the potential for "water piracy" in North East Greenland

    Science.gov (United States)

    Karlsson, Nanna B.; Dahl-Jensen, Dorthe

    2013-04-01

    The incorporation of subglacial processes in ice flow models remains a challenge while at the same time observational evidence increasingly underscores the important role liquid water plays in ice flow dynamics. One of the many problems ice flow models face (that also includes scarcity of data at the bed and the deformational properties of water-saturated sediments) is the different time-scales on which the processes operate. For example, observations indicate that subglacial water may be re-routed to a neighbouring ice stream in response to changes in surface elevation. This implies that ice flow models have to allow for changes in ice flow mode where, depending on the basal properties, the flow may be dominated by deformation or basal sliding. The re-routing of water between neighbouring ice streams is often termed "water piracy" and in this study we demonstrate that the potential for water piracy exists even in regions with very small surface elevation changes. We use a simple, vertically integrated, 2D-plane ice flow model based on the shallow ice flow approximation to model the large-scale changes in surface elevation of North East Greenland in response to gravity and mass balance. Considering time-scales of 100-500 years the model predicts changes in elevation of less than a metre per year which is in agreement with data from remote sensing. We then calculate the corresponding changes in hydrological pressure potential and use evidence from radio-echo sounding data to identify areas with basal melting and thus potential liquid water production. The corresponding change in hydrological pressure potential in response to the surface elevation changes is sufficient to divert the subglacial water to different pathways. This change in subglacial water pathways could be sufficient to change the ice flow mode from deformation to sliding and might initiate speed-up and/or slow-down of the ice streams at the margins of the basin.

  3. Structural investigation of aroylhydrazones in dimethylsulphoxide/water mixtures

    Science.gov (United States)

    Galić, Nives; Dijanošić, Adriana; Kontrec, Darko; Miljanić, Snežana

    Molecular structures of aroylhydrazones derived from salicylaldehyde, o-vanilin and nicotinic acid hydrazide in DMSO and DMSO/H2O mixtures have been studied by NMR, UV-Vis, ATR and Raman spectroscopy. The addition of water to the system did not induce the tautomeric conversion of the existing form constituted of the ketoamino hydrazide part and the enolimino aldehyde part, but it was involved in the formation of hydrated molecules. Vibrational spectra (ATR and Raman) clearly indicated hydrogen bonding of the studied hydrazones through the carbonyl, amino and hydroxyl groups with water molecules. Increasing the water content conversion from E to Z isomer was not observed.

  4. Apparatus for ground water chemistry investigations in field caissons

    International Nuclear Information System (INIS)

    Cokal, E.J.; Stallings, E.; Walker, R.; Nyhan, J.W.; Polzer, W.L.; Essington, E.H.

    1985-01-01

    Los Alamos is currently in its second season of ground water chemistry and hydrology experimentation in a field facility that incorporates clusters of six, 3-meter-diameter by 6-meter-deep, soil-filled caissons and required ancillaries. Initial experience gained during the 1983 field season indicated the need for further development of the technology of this type of experimentation supporting hydrologic waste management research. Uniform field application of water/matrix solutions to the caisson, matrix and tracer solution blending/storage, and devices for ground water sampling are discussed

  5. Modeling Nitrogen Fate and Transport at the Sediment-Water Interface

    Science.gov (United States)

    Diffusive mass transfer at media interfaces exerts control on the fate and transport of pollutants originating from agricultural and urban landscapes and affects the con-ditions of water bodies. Diffusion is essentially a physical process affecting the distribution and fate of va...

  6. Logistics of water and salt transport through the plant: structure and functioning of the xylem

    NARCIS (Netherlands)

    Boer, de A.H.; Volkov, V.

    2003-01-01

    The xylem is a long-distance transport system that is unique to higher plants. It evolved into a very sophisticated plumbing system ensuring controlled loading/unloading of ions and water and their effective translocation to the required sinks. The focus of this overview will be the intrinsic

  7. Logistics of water and salt transport through the plant design and fuctioning of the xylem

    NARCIS (Netherlands)

    de Boer, A.H.; Volkov, V.

    2003-01-01

    The xylem is a long-distance transport system that is unique to higher plants. It evolved into a very sophisticated plumbing system ensuring controlled loading/unloading of ions and water and their effective translocation to the required sinks. The focus of this overview will be the intrinsic

  8. Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

    DEFF Research Database (Denmark)

    Jensen, F B; Wang, T; Jones, D R

    1998-01-01

    + binding. Erythrocyte volume, plasma pH, and plasma HCO3- concentration also varied little with the degree of oxygenation. Diffusional water permeability was higher in oxygenated than deoxygenated RBCs. The RBCs have rapid band 3-mediated Cl- and HCO3- transport, which was not affected by degree...

  9. Transport of water vapor and inert gas mixtures through highly selective and highly permeable polymer membranes

    NARCIS (Netherlands)

    Metz, S.J.; van de Ven, W.J.C.; Potreck, Jens; Mulder, M.H.V.; Wessling, Matthias

    2005-01-01

    This paper studies in detail the measurement of the permeation properties of highly permeable and highly selective polymers for water vapor/nitrogen gas mixtures. The analysis of the mass transport of a highly permeable polymer is complicated by the presence of stagnant boundary layers at feed and

  10. Radial transport processes as a precursor to particle deposition in drinking water distribution systems.

    Science.gov (United States)

    van Thienen, P; Vreeburg, J H G; Blokker, E J M

    2011-02-01

    Various particle transport mechanisms play a role in the build-up of discoloration potential in drinking water distribution networks. In order to enhance our understanding of and ability to predict this build-up, it is essential to recognize and understand their role. Gravitational settling with drag has primarily been considered in this context. However, since flow in water distribution pipes is nearly always in the turbulent regime, turbulent processes should be considered also. In addition to these, single particle effects and forces may affect radial particle transport. In this work, we present an application of a previously published turbulent particle deposition theory to conditions relevant for drinking water distribution systems. We predict quantitatively under which conditions turbophoresis, including the virtual mass effect, the Saffman lift force, and the Magnus force may contribute significantly to sediment transport in radial direction and compare these results to experimental observations. The contribution of turbophoresis is mostly limited to large particles (>50 μm) in transport mains, and not expected to play a major role in distribution mains. The Saffman lift force may enhance this process to some degree. The Magnus force is not expected to play any significant role in drinking water distribution systems. © 2010 Elsevier Ltd. All rights reserved.

  11. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  12. The cellular contribution to effluent potassium and its relation to free water transport during peritoneal dialysis

    NARCIS (Netherlands)

    Coester, Annemieke M.; Struijk, Dirk G.; Smit, Watske; de Waart, Dirk R.; Krediet, Raymond T.

    2007-01-01

    BACKGROUND: Aquaporin-1 (AQP-1) dysfunction is one of the valid theories for decreased free water transport (FWT) in long-term peritoneal dialysis (PD) ultrafiltration failure (UFF). We questioned whether apoptosis of peritoneal cells could be reflected in an increased release of cellular (CR) K(+)

  13. Analysis of the sodium recirculation theory of solute-coupled water transport in small intestine

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkaer

    2002-01-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+-2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral...... permeabilities and pump constants of fluxes of water and electrolytes, volumes and ion concentrations of cell and lateral intercellular space (lis), and membrane potentials and conductances. Simulating physiological bioelectrical features together with cellular and paracellular fluxes of the sodium ion......, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions...

  14. Uranium facilitated transport by water-dispersible colloids in field and soil columns

    International Nuclear Information System (INIS)

    Crancon, P.; Pili, E.; Charlet, L.

    2010-01-01

    The transport of uranium through a sandy podsolic soil has been investigated in the field and in column experiments. Field monitoring, numerous years after surface contamination by depleted uranium deposits, revealed a 20 cm deep uranium migration in soil. Uranium retention in soil is controlled by the ≤ 50 μm mixed humic and clayey coatings in the first 40 cm i.e. in the E horizon. Column experiments of uranium transport under various conditions were run using isotopic spiking. After 100 pore volumes elution, 60% of the total input uranium is retained in the first 2 cm of the column. Retardation factor of uranium on E horizon material ranges from 1300 (column) to 3000 (batch). In parallel to this slow uranium migration, we experimentally observed a fast elution related to humic colloids of about 1-5% of the total-uranium input, transferred at the mean pore-water velocity through the soil column. In order to understand the effect of rain events, ionic strength of the input solution was sharply changed. Humic colloids are retarded when ionic strength increases, while a major mobilization of humic colloids and colloid-borne uranium occurs as ionic strength decreases. Isotopic spiking shows that both 238 U initially present in the soil column and 233 U brought by input solution are desorbed. The mobilization process observed experimentally after a drop of ionic strength may account for a rapid uranium migration in the field after a rainfall event, and for the significant uranium concentrations found in deep soil horizons and in groundwater, 1 km downstream from the pollution source. (authors)

  15. Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

    Science.gov (United States)

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

    2012-01-01

    Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

  16. Impact of freeze-drying, mixing and horizontal transport on water vapor in the upper troposphere and lower stratosphere (UTLS)

    Science.gov (United States)

    Poshyvailo, Liubov; Ploeger, Felix; Müller, Rolf; Tao, Mengchu; Konopka, Paul; Abdoulaye Diallo, Mohamadou; Grooß, Jens-Uwe; Günther, Gebhard; Riese, Martin

    2017-04-01

    Water vapor in the upper troposphere and lower stratosphere (UTLS) is a key player in the global radiation budget. Therefore, a realistic representation of the water vapor distribution in this region and the involved control processes is critical for climate models, but largely uncertain hitherto. It is known that the extremely low temperatures around the tropical tropopause cause the dominant factor controlling water vapor in the lower stratosphere. Here, we focus on additional processes, such as horizontal transport between tropics and extratropics, small-scale mixing, and freeze-drying. We assess the sensitivities of simulated water vapor in the UTLS from simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS). CLaMS is a Lagrangian transport model, with a parameterization of small-scale mixing (model diffusion) which is coupled to deformations in the large-scale flow. First, to assess the robustness of water vapor with respect to the meteorological datasets we examine CLaMS driven by ECMWF ERA-Interim and the Japanese 55-year reanalysis. Second, to investigate the effects of small-scale mixing we vary the parameterized mixing strength in the CLaMS model between the reference case with the mixing strength optimized to reproduce atmospheric trace gas observations and a purely advective simulation with parameterized mixing turned off. Also calculation of Lagrangian cold points gives further insight of the processes involved. Third, to assess the effects of horizontal transport between the tropics and extratropics we carry out sensitivity simulations with horizontal transport barriers along latitude circles at the equator, 15°N/S and 35°N/S. Finally, the impact of Antarctic dehydration is estimated from additional sensitivity simulations with switched off freeze-drying in the model at high latitudes of 50°N/S. Our results show that the uncertainty in the tropical tropopause temperatures between current reanalysis datasets causes significant

  17. Investigation of Locally Made Ceramic Filter for Household Water Treatment

    OpenAIRE

    Nurmiyanto, Awaluddin; Prasetya, Agus

    2012-01-01

    This research have objective to develop and evaluate the performance of ceramic filter in using locally available material at Yogyakarta. Ceramic filter are made by pressing a mixture of clay, discarded pottery (grog) and combustible material (coconut fiber) into the molder. Curving processes are then applied to form tubular shape before firing it using kiln (1005°C). Filtration test were performed gravitationally by flowing well water into ceramic filter. Filtered water quality was complying...

  18. Comparison of Contaminant Transport in Agricultural Drainage Water and Urban Stormwater Runoff.

    Directory of Open Access Journals (Sweden)

    Ehsan Ghane

    Full Text Available Transport of nitrogen and phosphorus from agricultural and urban landscapes to surface water bodies can cause adverse environmental impacts. The main objective of this long-term study was to quantify and compare contaminant transport in agricultural drainage water and urban stormwater runoff. We measured flow rate and contaminant concentration in stormwater runoff from Willmar, Minnesota, USA, and in drainage water from subsurface-drained fields with surface inlets, namely, Unfertilized and Fertilized Fields. Commercial fertilizer and turkey litter manure were applied to the Fertilized Field based on agronomic requirements. Results showed that the City Stormwater transported significantly higher loads per unit area of ammonium, total suspended solids (TSS, and total phosphorus (TP than the Fertilized Field, but nitrate load was significantly lower. Nitrate load transport in drainage water from the Unfertilized Field was 58% of that from the Fertilized Field. Linear regression analysis indicated that a 1% increase in flow depth resulted in a 1.05% increase of TSS load from the City Stormwater, a 1.07% increase in nitrate load from the Fertilized Field, and a 1.11% increase in TP load from the Fertilized Field. This indicates an increase in concentration with a rise in flow depth, revealing that concentration variation was a significant factor influencing the dynamics of load transport. Further regression analysis showed the importance of targeting high flows to reduce contaminant transport. In conclusion, for watersheds similar to this one, management practices should be directed to load reduction of ammonium and TSS from urban areas, and nitrate from cropland while TP should be a target for both.

  19. Comparison of Contaminant Transport in Agricultural Drainage Water and Urban Stormwater Runoff.

    Science.gov (United States)

    Ghane, Ehsan; Ranaivoson, Andry Z; Feyereisen, Gary W; Rosen, Carl J; Moncrief, John F

    2016-01-01

    Transport of nitrogen and phosphorus from agricultural and urban landscapes to surface water bodies can cause adverse environmental impacts. The main objective of this long-term study was to quantify and compare contaminant transport in agricultural drainage water and urban stormwater runoff. We measured flow rate and contaminant concentration in stormwater runoff from Willmar, Minnesota, USA, and in drainage water from subsurface-drained fields with surface inlets, namely, Unfertilized and Fertilized Fields. Commercial fertilizer and turkey litter manure were applied to the Fertilized Field based on agronomic requirements. Results showed that the City Stormwater transported significantly higher loads per unit area of ammonium, total suspended solids (TSS), and total phosphorus (TP) than the Fertilized Field, but nitrate load was significantly lower. Nitrate load transport in drainage water from the Unfertilized Field was 58% of that from the Fertilized Field. Linear regression analysis indicated that a 1% increase in flow depth resulted in a 1.05% increase of TSS load from the City Stormwater, a 1.07% increase in nitrate load from the Fertilized Field, and a 1.11% increase in TP load from the Fertilized Field. This indicates an increase in concentration with a rise in flow depth, revealing that concentration variation was a significant factor influencing the dynamics of load transport. Further regression analysis showed the importance of targeting high flows to reduce contaminant transport. In conclusion, for watersheds similar to this one, management practices should be directed to load reduction of ammonium and TSS from urban areas, and nitrate from cropland while TP should be a target for both.

  20. Increasing water vapor transport to the Greenland Ice Sheet revealed using self-organizing maps

    Science.gov (United States)

    Mattingly, Kyle S.; Ramseyer, Craig A.; Rosen, Joshua J.; Mote, Thomas L.; Muthyala, Rohi

    2016-09-01

    The Greenland Ice Sheet (GrIS) has been losing mass in recent decades, with an acceleration in mass loss since 2000. In this study, we apply a self-organizing map classification to integrated vapor transport data from the ERA-Interim reanalysis to determine if these GrIS mass loss trends are linked to increases in moisture transport to Greenland. We find that "moist" days (i.e., days featuring anomalously intense water vapor transport to Greenland) were significantly more common during 2000-2015 compared to 1979-1994. Furthermore, the two most intense GrIS melt seasons during the last 36 years were either preceded by a record percentage of moist winter days (2010) or occurred during a summer with a record frequency of moist days (2012). We hypothesize that moisture transport events alter the GrIS energy budget by increasing downwelling longwave radiation and turbulent fluxes of sensible and latent energy.

  1. Variation in material transport and water chemistry along a large ephemeral river in the Namib Desert

    Science.gov (United States)

    Jacobson, P.J.; Jacobson, K.M.; Angermeier, P.L.; Cherry, D.S.

    2000-01-01

    1. The chemical characteristics of floodwaters in ephemeral rivers are little known, particularly with regard to their organic loads. These rivers typically exhibit a pronounced downstream hydrological decay but few studies have documented its effect on chemical characteristics and material transport. To develop a better understanding of the dynamics of floods and associated material transport in large ephemeral rivers, floods of the ephemeral Kuiseb River in south-western Africa were tracked and repeatedly sampled at multiple points along the river's lower 220 km. 2. We quantified the composition and transport of solute and sediment loads in relation to longitudinal hydrological patterns associated with downstream hydrological decay. Source and sink areas for transported materials were identified, and the composition and transport dynamics of the organic matter load were compared to those described from more mesic systems. 3. Concentrations of sediments and solutes transported by floods in the Kuiseb River tended to increase downstream in association with pronounced hydrological decay. The contribution of particulate organic matter to total organic load is among the highest recorded, despite our observation of unusually high levels of dissolved organic matter. Hydrological decay resulted in deposition of all transported material within the lower Kuiseb River, with no discharge of water or materials to the Atlantic Ocean. 4. Our results suggest that longitudinal variation in surface flow and associated patterns of material transport renders the lower Kuiseb River a sink for materials transported from upstream. The downstream transport and deposition of large amounts of labile organic matter provides an important carbon supplement to heterotrophic communities within the river's lower reaches.

  2. Investigation on Floating Lid Construction, pit Water Storage, Ottrupgaard, Denmark

    DEFF Research Database (Denmark)

    Heller, Alfred

    At Ottrupgaard a pit water storage of 1,500 m3 and a lid area of about 700 m2 is built for seasonal storage of a solar collector field of 560 m2. The lid price is the largest component of a pit water store with a cost share of about 57%, more precisely 1,163 Dkr./m2. Due to the large share in price...... the development of lid constructions is crucial for the development of pit water storage and seasonal storage, as it seems that the development of solar collectors will not have a breakthrough in the near future.The Ottrupgaard lid design is basically a sandwich element construction of PUR-foam between two...... conditions floating on hot water. The test lids were examined for tightness by a number of means. The results showed critical construction errors of the first lid design. A redesigned lid showed acceptable results, but also some water penetration into the lid insulation. The entered water gathers...

  3. Sensitizing curium luminescence through an antenna protein to investigate biological actinide transport mechanisms.

    Science.gov (United States)

    Sturzbecher-Hoehne, Manuel; Goujon, Christophe; Deblonde, Gauthier J-P; Mason, Anne B; Abergel, Rebecca J

    2013-02-20

    Worldwide stocks of actinides and lanthanide fission products produced through conventional nuclear spent fuel are increasing continuously, resulting in a growing risk of environmental and human exposure to these toxic radioactive metal ions. Understanding the biomolecular pathways involved in mammalian uptake, transport and storage of these f-elements is crucial to the development of new decontamination strategies and could also be beneficial to the design of new containment and separation processes. To start unraveling these pathways, our approach takes advantage of the unique spectroscopic properties of trivalent curium. We clearly show that the human iron transporter transferrin acts as an antenna that sensitizes curium luminescence through intramolecular energy transfer. This behavior has been used to describe the coordination of curium within the two binding sites of the protein and to investigate the recognition of curium-transferrin complexes by the cognate transferrin receptor. In addition to providing the first protein-curium spectroscopic characterization, these studies prove that transferrin receptor-mediated endocytosis is a viable mechanism of intracellular entry for trivalent actinides such as curium and provide a new tool utilizing the specific luminescence of curium for the determination of other biological actinide transport mechanisms.

  4. In vitro investigation of intestinal transport mechanism of silicon, supplied as orthosilicic acid-vanillin complex.

    Science.gov (United States)

    Sergent, Thérèse; Croizet, Karine; Schneider, Yves-Jacques

    2017-02-01

    Silicon (Si) is one of the most abundant trace elements in the body. Although pharmacokinetics data described its absorption from the diet and its body excretion, the mechanisms involved in the uptake and transport of Si across the gut wall have not been established. Caco-2 cells were used as a well-accepted in vitro model of the human intestinal epithelium to investigate the transport, across the intestinal barrier in both the absorption and excretion directions, of Si supplied as orthosilicic acid stabilized by vanillin complex (OSA-VC). The transport of this species was found proportional to the initial concentration and to the duration of incubation, with absorption and excretion mean rates similar to those of Lucifer yellow, a marker of paracellular diffusion, and increasing in the presence of EGTA, a chelator of divalents cations including calcium. A cellular accumulation of Si, polarized from the apical side of cells, was furthermore detected. These results provide evidence that Si, ingested as a food supplement containing OSA-VC, crosses the intestinal mucosa by passive diffusion via the paracellular pathway through the intercellular tight junctions and accumulates intracellularly, probably by an uptake mechanism of facilitated diffusion. This study can help to further understand the kinetic of absorption of Si. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. [Investigation on contamination of Cryptosporidium and Giardia in drinking water and environmental water in Shanghai].

    Science.gov (United States)

    Zhang, Xiao-Ping; He, Yan-Yan; Zhu, Qian; Ma, Xiao-Jiang; Cai, Li

    2010-12-30

    To understand the contamination status of Cryptosporidium sp. and Giardia lamblia in drinking water, source water and environmental water in Shanghai. All water samples collected from drinking water, source water and environmental water were detected by a procedure of micromembrane filtration, immune magnetic separation (IMS), and immunofluorescent assay (IFA). Cryptosporidium oocysts and Giardia cysts were not found in 156 samples of the drinking water including finished water, tap water, or pipe water for directly drinking in communities. Among 70 samples either source water of water plants (15 samples), environmental water from Huangpu River(25), canal water around animal sheds(15), exit water from waste-water treatment plants(9), or waste water due to daily life(6), Cryptosporidium oocysts were detected in 1(6.7%), 2(8.0%), 7(46.7%), 1(11.1%), and 1(16.7%) samples, respectively; and Giardia cysts were detected in 1(6.7%), 3(12.0%), 6 (40.0%), 2(22.2%), and 2(33.3%), respectively. The positive rate of Cryptosporidium oocysts and Giardia cysts was 17.1% (12/70) and 20.0% (14/70), respectively. No Cryptosporidium oocysts and Giardia cysts have been detected in drinking water, but found in source water and environmental water samples in Shanghai.

  6. Mobility and transport of mercury and methylmercury in peat as a function of changes in water table regime and plant functional groups

    Science.gov (United States)

    Kristine M. Haynes; Evan S. Kane; Lynette Potvin; Erik A. Lilleskov; Randy Kolka; Carl P. J. Mitchell

    2017-01-01

    Climate change is likely to significantly affect the hydrology, ecology, and ecosystem function of peatlands, with potentially important but unclear impacts on mercury mobility within and transport from peatlands. Using a full-factorial mesocosm approach, we investigated the potential impacts on mercury mobility of water table regime changes (high and low) and...

  7. Experimental investigations on liquid water removal from the gas diffusion layer by reactant flow in a PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Kui; Li, Xianguo [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada); Park, Jaewan [Department of Mechanical and Aeronautical Engineering, University of California, Davis One Shields Ave., Davis, CA 95616 (United States)

    2010-09-15

    The cross flow from channel to channel through gas diffusion layer (GDL) under the land could play an important role for water removal in proton exchange membrane (PEM) fuel cells. In this study, characteristics of liquid water removal from GDL have been investigated experimentally, through measuring unsteady pressure drop in a cell which has the GDL initially wet with liquid water. The thickness of GDL is carefully controlled by inserting various thicknesses of metal shims between the plates. It has been found that severe compression of GDL could result in excessive pressure drop from channel inlet to channel outlet. Removing liquid water from GDL by cross flow is difficult for GDL with high compression levels and for low inlet air flow rates. However, effective water removal can still be achieved at high compression levels of GDL if the inlet air flow rate is high. Based on different compressed GDL thicknesses, different GDL porosities and permeabilities were calculated and their effects on the characteristics of liquid water removal from GDL were evaluated. Visualization of liquid water transport has been conducted by using transparent flow channel, and liquid water removal from GDL under the land was observed for all the tested inlet air flow rates, which confirms that cross flow is practically effective to remove the liquid water accumulated in GDL under the land area. (author)

  8. Pore-Scale Investigation of Micron-Size Polyacrylamide Elastic Microspheres (MPEMs) Transport and Retention in Saturated Porous Media

    KAUST Repository

    Yao, Chuanjin

    2014-05-06

    Knowledge of micrometer-size polyacrylamide elastic microsphere (MPEM) transport and retention mechanisms in porous media is essential for the application of MPEMs as a smart sweep improvement and profile modification agent in improving oil recovery. A transparent micromodel packed with translucent quartz sand was constructed and used to investigate the pore-scale transport, surface deposition-release, and plugging deposition-remigration mechanisms of MPEMs in porous media. The results indicate that the combination of colloidal and hydrodynamic forces controls the deposition and release of MPEMs on pore-surfaces; the reduction of fluid salinity and the increase of Darcy velocity are beneficial to the MPEM release from pore-surfaces; the hydrodynamic forces also influence the remigration of MPEMs in pore-throats. MPEMs can plug pore-throats through the mechanisms of capture-plugging, superposition-plugging, and bridge-plugging, which produces resistance to water flow; the interception with MPEM particulate filters occurring in the interior of porous media can enhance the plugging effect of MPEMs; while the interception with MPEM particulate filters occurring at the surface of low-permeability layer can prevent the low-permeability layer from being damaged by MPEMs. MPEMs can remigrate in pore-throats depending on their elasticity through four steps of capture-plugging, elastic deformation, steady migration, and deformation recovery. © 2014 American Chemical Society.

  9. An investigation of the electrical transport properties of graphene-oxide thin films

    International Nuclear Information System (INIS)

    Venugopal, Gunasekaran; Krishnamoorthy, Karthikeyan; Mohan, Rajneesh; Kim, Sang-Jae

    2012-01-01

    Highlights: ► Four terminal electrical transport characterization of graphene-oxide thin film. ► Low temperature R–T and I–V studies on GO thin film. ► Electrical transport obeys VRH mechanism supported by Raman spectra. ► GO characterizations by SEM, AFM, UV–vis, XRD, FTIR and XPS. ► GO-FET confirms the p-type semiconducting behavior. - Abstract: The electrical transport properties of graphene-oxide (GO) thin films were investigated. The GO was synthesized by a modified Hummers method and was characterized by X-ray diffraction and UV–visible spectroscopy. The thin film of GO was made on a Si/SiO 2 substrate by drop-casting. The surface morphology of the GO film was analyzed by using scanning electron microscopy and atomic force microscopy techniques. Temperature dependent resistance and current–voltage measurements were studied using four-terminal method at various temperatures (120, 150, 175, 200, 250 and 300 K) and their charge transport followed the 3D variable range hopping mechanism which was well supported by Raman spectra analysis. The presence of various functional groups in GO were identified by using high resolution X-ray photo electron (XPS) and Fourier transform infra red (FT-IR) spectroscopic techniques. Graphene-oxide thin film field effect transistor devices show p-type semiconducting behavior with a hole mobility of 0.25 cm 2 V −1 s −1 and 0.59 cm 2 V −1 s −1 when measured in air and vacuum respectively.

  10. Patterned gradient surface for spontaneous droplet transportation and water collection: simulation and experiment

    International Nuclear Information System (INIS)

    Tan, Xianhua; Zhu, Yiying; Shi, Tielin; Tang, Zirong; Liao, Guanglan

    2016-01-01

    We demonstrate spontaneous droplet transportation and water collection on wedge-shaped gradient surfaces consisting of alternating hydrophilic and hydrophobic regions. Droplets on the surfaces are modeled and simulated to analyze the Gibbs free energy and free energy gradient distributions. Big half-apex angle and great wettability difference result in considerable free energy gradient, corresponding to large driving force for spontaneous droplet transportation, thus causing the droplets to move towards the open end of the wedge-shaped hydrophilic regions, where the Gibbs free energy is low. Gradient surfaces are then fabricated and tested. Filmwise condensation begins on the hydrophilic regions, forming wedge-shaped tracks for water collection. Dropwise condensation occurs on the hydrophobic regions, where the droplet size distribution and departure diameters are controlled by the width of the regions. Condensate water from both the hydrophilic and hydrophobic regions are collected directionally to the open end of the wedge-shaped hydrophilic regions, agreeing with the simulations. Directional droplet transport and controllable departure diameters make the branched gradient surfaces more efficient than smooth surfaces for water collection, which proves that gradient surfaces are potential in water collection, microfluidic devices, anti-fogging and self-cleaning. (paper)

  11. Investigation of nanostructured electrocatalysts and mass transport phenomena in polymer electrolyte fuel cells

    Science.gov (United States)

    Goenaga, Gabriel A.

    Proton exchange membrane (PEM) fuel cells (FC) are promising devices in the search of clean and efficient technologies to reduce the use of fossil fuels. However, their poor performance in dynamic applications and high cost of platinum group metal (PGM) catalysts, have prevented them from becoming an affordable solution. This dissertation comprehend three research projects that study the mass transport phenomena in modified PEMs, the reduction of the amount of PGM catalyst used for oxygen reduction reaction (ORR) and the use of non-PGM catalysts as alternative catalyst to Pt for ORR. Nafion is the most used PEM for FC applications. Nafion proton conductivity is proportional to its degree of hydration, what imposes low temperature operation to maintain appropriate water content. In this research, Nafion composite membranes doped with hydrophilic metal inorganic particles have been studied using pulse field gradient (PFG) nuclear magnetic resonance (NMR). The Nafion composite membranes were found to have higher water uptake, higher water retention, higher water diffusion and, in some cases, lower methanol diffusion (crossover) than the filler free Nafion membrane. The amount of Pt and PGM catalysts supported on carbon used in the electrodes, has a great impact in the PEMFC cost. In particular, it is of high relevance to reduce the amount of Pt in the cathode electrode, in which the sluggish ORR demands four to five times more Pt catalyst than in the anode. In this thesis is shown that the use of aligned carbon nanotubes (ACNTs) as Pt support, allows a more uniform distribution of the Pt nanoparticles, what in addition to their high hydrophobicity and high corrosive resistance, lead to improved mass transport and stability of the membrane electrode assembly (MEA), when compared to a benchmark MEA that uses Pt catalyst supported on carbon black. The improvement was accomplished using less Pt than in the benchmark MEA. Replacing Pt with non-PGM catalyst can lead to an

  12. Experimental investigation of the stability of the floating water bridge

    Science.gov (United States)

    Montazeri Namin, Reza; Azizpour Lindi, Shiva; Amjadi, Ahmad; Jafari, Nima; Irajizad, Peyman

    2013-09-01

    When a high voltage is applied between two beakers filled with deionized water, a floating bridge of water is formed in between exceeding the length of 2 cm when the beakers are pulled apart. Currently two theories regarding the stability of the floating water bridge exist, one suggesting that the tension caused by electric field in the dielectric medium is holding the bridge and the other suggesting surface tension to be responsible for the vertical equilibrium. We construct experiments in which the electric field and the geometry of the bridge are measured and compared with predictions of theories of the floating water bridge stability. We use a numerical simulation for estimation of the electric field. Our results indicate that the two forces of dielectric and surface tensions hold the bridge against gravity simultaneously and, having the same order of magnitude, neither of the two forces are negligible. In bridges with larger diameters, the effect of dielectric tension is slightly more in the vertical equilibrium than surface tension. Results show that the stability can be explained by macroscopic forces, regardless of the microscopic changes in the water structure.

  13. Use of stable isotopes for estimating water and nitrogen transport in plants

    International Nuclear Information System (INIS)

    Grygoryuk, I.P.; Petrenko, N.I.; Shvedova, O.Yu.; Tkachev, V.I.; Yaroshenko, O.A.

    1998-01-01

    Peculiarities in the response of various wheat cultivars and maize hybrids to water deficiency were studied in laboratory and vegetation experiments. Their resistance to extemal environmental factors was estimated by changes in nitrogen ( 15 N) and water (HDO) accumulation, transport and distribution in plant organs. The water supply was maintained at 60% FWC (control) and was reduced to 30% FWC (experiment) in the absence of plant watering during different stages or with use of polyethylene glycol. Decrease in water potential of medium from -0.05 (control) to -0.5, -0.9 and -1.6 MPa resulted in inhibition of water absorption, transport and distribution in spring wheat organs. After 24-hour stress, root absorption of water of drought-resistant varieties as compared to non-drought resistant ones was more sensitive, during 5, 10 and 15 min intervals after HDO introduction in nutrition medium. Strong depression of water exchange was observed at weaker stress in non-resistant variety. HDO absorption of the low part of the stem at short exposure resembled that of roots. The 24-hour stress revealed the tendency to sharper inhibition of absorption of labelled water in leaves of resistant variety. At a more durable stress the intensity of leaf water-exchange resistant variety was stabilized, while in the non-resistant variety it was reduced considerably. The intensity of HDO and 15 N exchange under stress conditions depended on the lability of regulator mechanism of water transport. Genotypic specificity of N use by wheat and maize plants depending on water supply and inclusion of 15 N in total and protein N was found. The 15 N content in total N in spring wheat cultivars under optimum water supply and under drought made 3.65 to 6.20 and 1.69 to 3.47, respectively. The 15 N content in protein N under the above conditions was 3.03 to 5.96 and 2.36 to 2.93, respectively. At water stress the main mass of labelled N in plant roots and stems was localized, while its intake into

  14. Water transport confined in graphene oxide channels through the rarefied effect.

    Science.gov (United States)

    Chen, Bo; Jiang, Haifeng; Liu, Xiang; Hu, Xuejiao

    2018-02-21

    Understanding the mechanism of water transport inside an interlayer between graphene-based plates has tremendous value for theoretical studies and industrial applications. The fluid flow confined in nano-scaled spaces experiences a slip velocity near the wall, which is significantly different to that of bulk water. Here we propose a model combining classic hydrodynamics with kinetic theory to depict the dependency of the slip effect on the oxide concentration of valley plates. The influence of oxidized graphene on water flow is a comprehensive result of a slipped boundary, and depends on both the diffuse reflection coefficient of the wall, and the shrunken effective passageway caused by the electrostatic interactions between the oxidized surface and the water molecules. The former effect enhances the water flow, which reduces with increasing oxide concentration, while the latter effect inhibits water flow. We examine the diffuse reflection coefficient and the shrunken effective passageway at different oxide concentrations of the GO sheets by molecular dynamics simulations, and we quantitively predict the flux relationship at various concentrations. This work provides a molecular insight into transport processes of confined water and a useful guideline for the design of perfect graphene-derived membranes for desalination.

  15. Complexity in the validation of ground-water travel time in fractured flow and transport systems

    International Nuclear Information System (INIS)

    Davies, P.B; Hunter, R.L.; Pickens, J.F.

    1991-02-01

    Ground-water travel time is a widely used concept in site assessment for radioactive waste disposal. While ground-water travel time was originally conceived to provide a simple performance measure for evaluating repository sites, its definition in many flow and transport environments is ambiguous. The US Department of Energy siting guidelines (10 CFR 960) define ground-water travel time as the time required for a unit volume of water to travel between two locations, calculated by dividing travel-path length by the quotient of average ground-water flux and effective porosity. Defining a meaningful effective porosity in a fractured porous material is a significant problem. Although the Waste Isolation Pilot Plant (WIPP) is not subject to specific requirements for ground-water travel time, travel times have been computed under a variety of model assumptions. Recently completed model analyses for WIPP illustrate the difficulties in applying a ground-water travel-time performance measure to flow and transport in fractured, fully saturated flow systems. 12 refs., 4 figs

  16. Investigation of toxic influence of Ignalina NPP waste water on Spirodela polyrrhiza culture

    International Nuclear Information System (INIS)

    Lakachauskiene, R.; Marchiulioniene, D.

    1995-01-01

    The influence of Ignalina NPP waste waters and of water taken in different biotop of lake Drukshiai on Spirodela polyrrhiza culture (growth intensity, biomass and morphological changes) was investigated. It was revealed that most polluted waters formed by Ignalina NPP outcomes were from industrial - rain sewerage and economic - domestic waste waters. Toxicity of all investigated waters was higher in autumn (October) than it was in spring (March -April). Comparative analysis of the data obtained in 1992-1994 indicated the growing tendency of toxicity in Ignalina NPP waste waters as well as lake Drukshiai water. (author). 5 refs., 4 figs

  17. Water level determination for transportation projects : mean high water manual, final report, November 2009.

    Science.gov (United States)

    2009-11-01

    To ensure proficient network management and safe usage of navigable waterways especially in waters that are : subject to tides, it is essential that the height of the water at various tidal phases be known. This knowledge is also : essential for prop...

  18. Investigation on the oxygen transport mechanisms in the Sarcheshmeh waste rock dumps

    Directory of Open Access Journals (Sweden)

    Saeed Yousefi

    2015-04-01

    rates: a laboratory study comparing oxygen fluxes and rates of oxidation product release. Canadian Geotechnical Journal, 31(3: 375-383. Jannesar Malakooti, S., Shafaei Tonkaboni, S.Z., Noaparast, M., Ardejani, F.D. and Naseh, R., 2014. Characterisation of the Sarcheshmeh copper mine tailings, Kerman province, southeast of Iran. Environmental Earth Sciences, 71(5: 2267-2291. Jaynes, D.B., Rogowski, A.S. and Pionke, H.B., 1984. Acid mine drainage from reclaimed coal strip mines 1. Model description. Water Resources Research, 20(2: 233-242. Morin, K.A., Cherry, J.A., Dave, N.K., Lim, T.P. and Vivyurka, A.J., 1988. Migration of acidic groundwater seepage from uranium-tailings impoundments, 1. Field study and conceptual hydrogeochemical model. Journal of Contaminant Hydrology, 2(4: 271-303. Wunderly, M.D., Blowes, D.W., Frind, E.O. and Ptacek, C.J., 1986. Sulfide mineral oxidation and subsequent reactive transport of oxidation products in mine tailings impoundments: A numerical model. Water Resources Research, 32(10: 3173-3187.

  19. Investigation of radioactive cesium transportation from forest canopy to floor by litterfall, stemflow and throughfall in northern Fukushima

    Science.gov (United States)

    Endo, I.; Ohte, N.; Iseda, K.; Tanoi, K.; Hirose, A.; Kobayashi, N. I.; Murakami, M.; Tokuchi, N.; Ohashi, M.

    2015-12-01

    After the Fukushima Daiichi nuclear power plant accident due to Great East Japan Earthquake in March 11th 2011, large areas of forest have been highly contaminated by the radioactive nuclides. Most of the deposited radioactive material to the canopy is then washed out with rainfall or leaf fall due to the tree phenology. There have been studies showing that the amount of 137Cs transportation differs among litter components and water pathways, and was affected by seasonal variations. Thus, to evaluate the amount of 137Cs flux from canopy to forest floor, continuous monitoring of each component (litterfall, throughfall and stemflow) is required. We investigated the annual transfer of 137Cs from the forest canopy to the floor by litterfall, throughfall and stemflow at two different forest types in northern Fukushima after two years from the accident. Seasonal variations in 137Cs transportation and differences between forests types were also determined. Forest sites were set in the upstream part of Kami-Oguni River catchment at Date city, which locates approximately 50km northwest from the Fukushima Dai-ichi Nuclear Power Plant. The study sites consisted of two deciduous (Mixed deciduous-1, Mixed deciduous-2) and one cedar (Cedar plantation) stands. The cumulative 137Cs transportation from the forest canopy to the floor was 6.6 kBq m-2 year-1 for the Mixed deciduous-1, 3.9 kBq m-2 year-1 for the Mixed deciduous-2 and 11.0 kBq m-2 year-1 for the Cedar plantation. 137Cs transportation with litterfall increased in the defoliation period which correlated with the increased amount of litterfall. 137Cs transportation with throughfall and stemflow increased in the rainy season. 137Cs flux by litterfall was higher in Cedar plantation compared with that of mixed deciduous forests, while the opposite result was obtained for stemflow. The ratio of annual 137Cs flux and the estimated 137Cs amount deposited in the forests will be discussed.

  20. A theoretical investigation of water adsorption on titanium dioxide surfaces

    Science.gov (United States)

    Fahmi, Adil; Minot, Christian

    1994-03-01

    Water adsorption on various crystallographic faces of TiO 2 (anatase and rutile) are calculated using a periodic Hartree-Fock method. Titanium oxide is an amphoteric compound. Water adsorbs on the acidic site, the titanium atom, and then dissociates to give hydroxyl groups. The adsorption energy is larger on the (110) face of the rutile structure than on other faces and is correlated with its very acidic sites. The OH groups are oriented to maximize hydrogen bonding. Hydrogen bonding is particularly important for molecular adsorption on the (100) face of the rutile structure; in this case, the molecular adsorption becomes competitive with the dissociative one. The thermodynamics of water adsorption strongly favor dissociation when singly-coordinated oxygen atoms are present on the surface as it is in a perfectly truncated anatase surface.

  1. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports

    Science.gov (United States)

    Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea. PMID:27410682

  2. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports.

    Science.gov (United States)

    Daryabor, Farshid; Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea.

  3. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports.

    Directory of Open Access Journals (Sweden)

    Farshid Daryabor

    Full Text Available A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea.

  4. Co-current air-water flow in downward sloping pipes : Transport of capacity reducing gas pockets in wastewater mains

    NARCIS (Netherlands)

    Pothof, I.W.M.

    2011-01-01

    Air-water flow is an undesired condition in many systems for the transportation of water or wastewater. Air in storm water tunnels may get trapped and negatively affect the system. Air pockets in hydropower tunnels or sewers may cause blow-back events and inadmissible pressure spikes. Water pipes

  5. Water quality investigation of Francis Slocum Lake, Luzerne County, Pennsylvania

    Science.gov (United States)

    Barker, James L.

    1978-01-01

    This report summarizes water-quality data collected in the Francis Slocum Lake drainage basin, Pennsylvania, during an assessment from October 1976 to September 1977. Data were collected for nitrogen, phosphorus, carbon, and fecal coliform and fecal streptococcal bacteria.Results of the restricted sampling indicate that nutrient recycling within the lake is sufficient to support the periodic luxurient growth of algae and aquatic weeds. Inflows are not contributing high concentrations of nutrients to the ecosystem. Sampling for enteric bacteria indicate the sanitary quality is sufficiently high for water-contact recreation.

  6. Airborne differential absorption lidar system for water vapor investigations

    Science.gov (United States)

    Browell, E. V.; Carter, A. F.; Wilkerson, T. D.

    1981-01-01

    Range-resolved water vapor measurements using the differential-absorption lidar (DIAL) technique is described in detail. The system uses two independently tunable optically pumped lasers operating in the near infrared with laser pulses of less than 100 microseconds separation, to minimize concentration errors caused by atmospheric scattering. Water vapor concentration profiles are calculated for each measurement by a minicomputer, in real time. The work is needed in the study of atmospheric motion and thermodynamics as well as in forestry and agriculture problems.

  7. Investigation of interactions between water and ion exchanger perfluorinated membranes

    International Nuclear Information System (INIS)

    Ben Said, Chakir

    1983-01-01

    In this research thesis, the author, by using nuclear magnetic resonance (NMR), shows the privileged situation of the first absorbed water molecules which come and fix about cations and fill up the first hydration sphere. He reports the study of Nafion membranes provided by DuPont de Nemours: chemical definition (chemical structure, properties, and microstructure), interest of the use of NMR, results and discussion (influence of water content, of temperature, of thermal cycling), and other results obtained by using different techniques (electronic paramagnetic resonance or EPR, differential calorimetry and thermo-porometry, mechanical measurements) [fr

  8. Investigation of methods for fabricating, characterizing, and transporting cryogenic inertial-confinement-fusion tartets

    International Nuclear Information System (INIS)

    Fanning, J.J.; Kim, K.

    1981-01-01

    The objective of this work is to investigate methods for fabricating, characterizing and transporting cryogenic inertial confinement fusion targets on a continuous basis. A microprocessor-based data acquisition system has been built that converts a complete target image to digital data, which are then analyzed by automated software procedures. The low temperatures required to freeze the hydrogen isotopes contained in a target is provided by a cryogenic cold chamber capable of attaining 15 K. A new method for target manipulation and positioning is studied that employs molecular gas beams to levitate a target and an electrostatic quadrupole structure to provide for its lateral containment. Since the electrostatic target-positioning scheme requires that the targets be charged, preliminary investigation has been carried out for a target-charging mechanism based on ion-bombardment

  9. Investigating water meter performance in developing countries: A ...

    African Journals Online (AJOL)

    2011-10-07

    Oct 7, 2011 ... real losses (leakage) or apparent (commercial) losses. Apparent losses occur due to illegal use, inaccuracies in metering, meter reading errors, data handling and billing errors, and have a negative impact on utility revenue and accuracy of water usage data (AWWA, 2009). One of the tools that has received ...

  10. Investigation of Cooling Water Injection into Supersonic Rocket Engine Exhaust

    Science.gov (United States)

    Jones, Hansen; Jeansonne, Christopher; Menon, Shyam

    2017-11-01

    Water spray cooling of the exhaust plume from a rocket undergoing static testing is critical in preventing thermal wear of the test stand structure, and suppressing the acoustic noise signature. A scaled test facility has been developed that utilizes non-intrusive diagnostic techniques including Focusing Color Schlieren (FCS) and Phase Doppler Particle Anemometry (PDPA) to examine the interaction of a pressure-fed water jet with a supersonic flow of compressed air. FCS is used to visually assess the interaction of the water jet with the strong density gradients in the supersonic air flow. PDPA is used in conjunction to gain statistical information regarding water droplet size and velocity as the jet is broken up. Measurement results, along with numerical simulations and jet penetration models are used to explain the observed phenomena. Following the cold flow testing campaign a scaled hybrid rocket engine will be constructed to continue tests in a combusting flow environment similar to that generated by the rocket engines tested at NASA facilities. LaSPACE.

  11. Crossing the boundary: numerical investigation of water entry conditions

    Science.gov (United States)

    Angelidis, Dionysios; Sotiropoulos, Fotis

    2017-11-01

    Several engineering and scientific applications involve water impact problems. To accurately capture the dynamics of the cavity formation and the water ejected as a body hits the water, the formidable range of temporal and spatial scales should accurately be resolved with affordable computational cost. We have enhanced the potential of the two-phase flow version of the immersed-boundary adaptive mesh refinement flow solver, developed by our group, to perform high-fidelity two-phase flow calculations on locally refined grids. We employ a level-set method and tackle the computational challenges arise during the explicit solution of a mass-conserving reinitialization equation. In contrast to conventional approaches, we propose a convergence criterion which enables the number of iterations to be self-adjusted based on the values of the distance function. The efficiency of our method is demonstrated by performing two-phase flow calculations including the high-speed water entry of a V-shaped wedge. Our results are found to be in good agreement with experimental measurements and enable us to gain insight into the instability that arises on the onset of the closure phase of the cavity. This material is based upon work supported by the National Science Foundation (CBET-1509071).

  12. A preliminary investigation of the water use efficiency of sweet ...

    African Journals Online (AJOL)

    ... compared to Ukulinga research farm. The results from this study showed that the WUE of sweet sorghum was sensitive to plant density. The WUE values confirm that sweet sorghum has high WUE under different climatic conditions. Keywords: water use efficiency; ethanol yield; biofuel crop; plant density, sweet sorghum, ...

  13. An investigation into the prevalence of water borne diseases in ...

    African Journals Online (AJOL)

    user

    2Sustainable Development Study Centre, Government College University, Lahore, Pakistan. 3Government Post Graduate Degree College, Lahore, Pakistan. ...... Health benefits from improvements in water supply and sanitation: Survey and analysis of the literature on selected diseases. WASH Techn. Rep., 66, April.

  14. ESKIMO1 disruption in Arabidopsis alters vascular tissue and impairs water transport.

    Directory of Open Access Journals (Sweden)

    Valérie Lefebvre

    Full Text Available Water economy in agricultural practices is an issue that is being addressed through studies aimed at understanding both plant water-use efficiency (WUE, i.e. biomass produced per water consumed, and responses to water shortage. In the model species Arabidopsis thaliana, the ESKIMO1 (ESK1 gene has been described as involved in freezing, cold and salt tolerance as well as in water economy: esk1 mutants have very low evapo-transpiration rates and high water-use efficiency. In order to establish ESK1 function, detailed characterization of esk1 mutants has been carried out. The stress hormone ABA (abscisic acid was present at high levels in esk1 compared to wild type, nevertheless, the weak water loss of esk1 was independent of stomata closure through ABA biosynthesis, as combining mutant in this pathway with esk1 led to additive phenotypes. Measurement of root hydraulic conductivity suggests that the esk1 vegetative apparatus suffers water deficit due to a defect in water transport. ESK1 promoter-driven reporter gene expression was observed in xylem and fibers, the vascular tissue responsible for the transport of water and mineral nutrients from the soil to the shoots, via the roots. Moreover, in cross sections of hypocotyls, roots and stems, esk1 xylem vessels were collapsed. Finally, using Fourier-Transform Infrared (FTIR spectroscopy, severe chemical modifications of xylem cell wall composition were highlighted in the esk1 mutants. Taken together our findings show that ESK1 is necessary for the production of functional xylem vessels, through its implication in the laying down of secondary cell wall components.

  15. Solute transport modelling in a coupled water and heat flow system applied to cold regions hydrogeology

    Science.gov (United States)

    Frampton, Andrew; Destouni, Georgia

    2016-04-01

    In cold regions, flow in the unsaturated zone is highly dynamic with seasonal variability and changes in temperature, moisture, and heat and water fluxes, all of which affect ground freeze-thaw processes and influence transport of inert and reactive waterborne substances. In arctic permafrost environments, near-surface groundwater flow is further restricted to a relatively shallow and seasonally variable active layer, confined by perennially frozen ground below. The active layer is typically partially saturated with ice, liquid water and air, and is strongly dependent on seasonal temperature fluctuations, thermal forcing and infiltration patterns. Here there is a need for improved understanding of the mechanisms controlling subsurface solute transport in the partially saturated active layer zone. Studying solute transport in cold regions is relevant to improve the understanding of how natural and anthropogenic pollution may change as activities in arctic and sub-arctic regions increase. It is also particularly relevant for understanding how dissolved carbon is transported in coupled surface and subsurface hydrological systems under climate change, in order to better understand the permafrost-hydrological-carbon climate feedback. In this contribution subsurface solute transport under surface warming and degrading permafrost conditions is studied using a physically based model of coupled cryotic and hydrogeological flow processes combined with a particle tracking method. Changes in subsurface water flows and solute transport travel times are analysed for different modelled geological configurations during a 100-year warming period. Results show that for all simulated cases, the minimum and mean travel times increase non-linearly with warming irrespective of geological configuration and heterogeneity structure. The travel time changes are shown to depend on combined warming effects of increase in pathway length due to deepening of the active layer, reduced transport

  16. An inversion of the estuarine circulation by sluice water discharge and its impact on suspended sediment transport

    Science.gov (United States)

    Schulz, Kirstin; Gerkema, Theo

    2018-01-01

    The Wadden Sea is characterized by a complex topography of branching channels and intertidal flats, in which the interplay between fresh water discharges, wind forcing and the tidal current causes sediment transport rates and direction to be highly variable in space and time. During three field campaigns, indications of a negative estuarine circulation have been found in a channel adjacent to the coast in the Western Dutch Wadden Sea. Contrary to the classical picture of estuarine circulation, a periodic density stratification was observed that builds up during flood and breaks down during ebb. This can be related to a large freshwater source at the mouth of the channel, the sluice in Kornwerderzand. In this study, observations of this phenomenon are presented, and with the help of a numerical model the different drivers for residual suspended matter transport in this area, namely tidal asymmetries in the current velocity and the above mentioned periodic stratification, are investigated. It is found that the residual current in the area of interest points in ebb direction, caused by both the elongated ebb flow phase and the periodic stratification. On the contrary, the stronger flood currents cause a transport of suspended matter in flood direction. This transport is counteracted and therefore diminished by the effects of the sluice discharge.

  17. Investigating tides, where does all the water go?

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will aim to complete a project investigating and researching tides. Each student should seek to develop an understanding of what causes tides and why sea levels change between high and low tide. Investigate and become familiar with tides as a natural feature in the local environment. Explore ways in which tides affect the behaviour of plants, animals and people.

  18. The role of the complete Coriolis force in cross-equatorial transport of the Antarctic Bottom Water

    Science.gov (United States)

    Stewart, Andrew; Dellar, Paul

    2010-05-01

    We investigate the equatorial crossing of the Antarctic Bottom Water using a shallow water model that includes the complete Coriolis force. Most theoretical models of the atmosphere and ocean neglect the component of the Coriolis force associated with the horizontal component of the Earth's rotation vector, the so-called traditional approximation. This approximation is typically justified on the basis that ratio of the ocean depth to the Rossby radius of deformation is negligibly small, H-Rd ≪ 1. However, the steep topography and weak stratification in the abyssal ocean magnify the role of the non-traditional component of the Coriolis force. This is most pronounced in equatorial regions, where the traditional component of the Coriolis force is weakest and the non-traditional component is strongest. The inclusion of the complete Coriolis force gives rise to a range of very long sub-inertial waves, whose frequencies lie below the inertial frequency, in the two-layer shallow water equations. These waves have a dramatically different structure to their traditional counterparts, particularly when the stratification is weak. We focus on the flow of the Antarctic Bottom Water from the Brazil Basin in the western South Atlantic to the Guiana Basin in the western North Atlantic. In this region, the current traverses a deep channel directed westwards and very slightly northwards across the equator. Previous attempts to model this flow have struggled to explain why the cross-equatorial transport is so high, with around 2.0-2.2 Sv exiting at the northern end of the channel. We present analytical and numerical solutions of the non-traditional shallow water equations for the cross-equatorial flow of the Antarctic Bottom Water. We obtain analytical solutions by considering the steady-state flow of a single layer of shallow water through a northwesterly channel with a simple geometry. We assume zero potential vorticity, as it may be shown that fluid whose potential vorticity q

  19. Water and Salt Transport Properties of Triptycene-Containing Sulfonated Polysulfone Materials for Desalination Membrane Applications.

    Science.gov (United States)

    Luo, Hongxi; Aboki, Joseph; Ji, Yuanyuan; Guo, Ruilan; Geise, Geoffrey M

    2018-01-31

    A series of triptycene-containing sulfonated polysulfone (TRP-BP) materials was prepared via condensation polymerization, and the desalination membrane-relevant fundamental water and salt transport properties (i.e., sorption, diffusion, and permeability coefficients) of the polymers were characterized. Incorporating triptycene into sulfonated polysulfone increased the water content of the material compared to sulfonated polysulfone materials that do not contain triptycene. No significant difference in salt sorption was observed between TRP-BP membranes and other sulfonated polysulfone membranes, suggesting that the presence of triptycene in the polymer did not dramatically affect thermodynamic interactions between salt and the polymer. Both water and salt diffusion coefficients in the TRP-BP membranes were suppressed relative to other sulfonated polysulfone materials with comparable water content, and these phenomena may result from the influence of triptycene on polymer chain packing and/or free-volume distribution, which could increase the tortuosity of the transport pathways in the polymers. Enhanced water/salt diffusivity selectivity was observed for some of the TRP-BP membranes relative to those materials that did not contain triptycene, and correspondingly, incorporation of triptycene into sulfonated polysulfone resulted in an increase, particularly for acid counterion form TRP-BP materials, in water/salt permeability selectivity, which is favorable for desalination membrane applications.

  20. Swelling kinetics and electrical charge transport in PEDOT:PSS thin films exposed to water vapor.

    Science.gov (United States)

    Sarkar, Biporjoy; Jaiswal, Manu; Satapathy, Dillip K Kumar

    2018-04-16

    We report the swelling kinetics and evolution of the electrical charge transport in poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) thin films subjected to water vapor. Polymer films swell by the diffusion of water vapor and are found to undergo structural relaxations. Upon exposure to water vapor, primarily the hygroscopic PSS shell, which surrounds the conducting PEDOT-rich cores, takes up water vapor and subsequently swells. We found that the degree of swelling largely depends on the PEDOT to PSS ratio. Swelling driven microscopic rearrangement of the conducting PEDOT-rich cores in the PSS matrix strongly influences the electrical charge transport of the polymer film. Swelling induced increase as well as decrease of electrical resistance are observed in polymer films having different PEDOT to PSS ratio. This anomalous charge transport behavior in PEDOT:PSS films is reconciled by taking into account the contrasting swelling behavior of the PSS and the conducting PEDOT-rich cores leading to spatial segregation of PSS in films with PSS as a minority phase and by a net increase in mean separation between conducting PEDOT-rich cores for films having abundance of PSS. © 2018 IOP Publishing Ltd.

  1. Improvement of water transport mechanisms during potato drying by applying ultrasound.

    Science.gov (United States)

    Ozuna, César; Cárcel, Juan A; García-Pérez, José V; Mulet, Antonio

    2011-11-01

    The drying rate of vegetables is limited by internal moisture diffusion and convective transport mechanisms. The increase of drying air temperature leads to faster water mobility; however, it provokes quality loss in the product and presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during convective drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve convective drying of potato and quantify the influence of the applied power in the water transport mechanisms. Drying kinetics of potato cubes were increased by the ultrasonic application. The influence of power ultrasound was dependent on the ultrasonic power (from 0 to 37 kW m(-3) ), the higher the applied power, the faster the drying kinetic. The diffusion model considering external resistance to mass transfer provided a good fit of drying kinetics. From modelling, it was observed a proportional and significant (P < 0.05) influence of the applied ultrasonic power on the identified kinetic parameters: effective moisture diffusivity and mass transfer coefficient. The ultrasonic application during drying represents an interesting alternative to traditional convective drying by shortening drying time, which may involve an energy saving concerning industrial applications. In addition, the ultrasonic effect in the water transport is based on mechanical phenomena with a low heating capacity, which is highly relevant for drying heat sensitive materials and also for obtaining high-quality dry products. Copyright © 2011 Society of Chemical Industry.

  2. Modified finite element transport model, FETRA, for sediment and radionuclide migration in open coastal waters

    International Nuclear Information System (INIS)

    Onishi, Y.; Arnold, E.M.; Mayer, D.W.

    1979-08-01

    The finite element model, FETRA, simulates transport of sediment and radionuclides (and other contaminants, such as heavy metals, pesticides, and other toxic substances) in surface water bodies. The model is an unsteady, two-dimensional (longitudinal and lateral) model which consists of the following three submodels coupled to include sediment-contaminant interactions: (1) sediment transport submodel, (2) dissolved contaminant transport submodel, and (3) particulate contaminant (contaminant adsorbed by sediment) transport submodel. Under the current phase of the study, FETRA was modified to include sediment-wave interaction in order to extend the applicability of the model to coastal zones and large lakes (e.g., the Great Lakes) where wave actions can be one of the dominant mechanisms to transport sediment and toxic contaminant. FETRA was further modified to handle both linear and quadratic approximations to velocity and depth distributions in order to be compatible with various finite element hydrodynamic models (e.g., RMA II and CAFE) which supply hydrodynamic input data to FETRA. The next step is to apply FETRA to coastal zones to simulate transport of sediment and radionuclides with their interactions in order to test and verify the model under marine and large lacustrine environments

  3. Regional water implications of reducing oil imports with liquid transportation fuel alternatives in the United States.

    Science.gov (United States)

    Jordaan, Sarah M; Diaz Anadon, Laura; Mielke, Erik; Schrag, Daniel P

    2013-01-01

    The Renewable Fuel Standard (RFS) is among the cornerstone policies created to increase U.S. energy independence by using biofuels. Although greenhouse gas emissions have played a role in shaping the RFS, water implications are less understood. We demonstrate a spatial, life cycle approach to estimate water consumption of transportation fuel scenarios, including a comparison to current water withdrawals and drought incidence by state. The water consumption and land footprint of six scenarios are compared to the RFS, including shale oil, coal-to-liquids, shale gas-to-liquids, corn ethanol, and cellulosic ethanol from switchgrass. The corn scenario is the most water and land intense option and is weighted toward drought-prone states. Fossil options and cellulosic ethanol require significantly less water and are weighted toward less drought-prone states. Coal-to-liquids is an exception, where water consumption is partially weighted toward drought-prone states. Results suggest that there may be considerable water and land impacts associated with meeting energy security goals through using only biofuels. Ultimately, water and land requirements may constrain energy security goals without careful planning, indicating that there is a need to better balance trade-offs. Our approach provides policymakers with a method to integrate federal policies with regional planning over various temporal and spatial scales.

  4. Sorption of PAHs to humic acid- and iron(III)carbon ate particles by using passive dosing vials for investigating the transport of organic contamination in stormwater runoff

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Mikkelsen, Peter Steen; Baun, Anders

    2013-01-01

    During the last decades, the growing urbanisation a nd increasing anthropogenic activities in urban areas have turned urban stormwater runoff int o a surface water quality contamination problem. The concerns of urban stormwater runoff as a source of contamination in the receiving surface water...... (lakes, rivers or sea) have been raised by researchers throughout the world (e.g. Broman et. al., 1987, and Xanthopoulos et. al., 1990), and have in Europe gained increased interest in relation to the implementatio n of the Water Framework Directive (WFD, 2000/60/EC). Particles (often defined as >0.45 μm...... abundance, and knowledge about their facilitated transport of persistent organic polluti on in natural waters, they are likely to diminish the efficiency of engineered treatment sys tems unless appropriately accounted for. In this work organic and inorganic nanosized partic les were investigated...

  5. Effects of water content on reactive transport of Sr in Chernobyl sand columns

    Energy Technology Data Exchange (ETDEWEB)

    Szenknect, S. [CEA, Tracers Applications Laboratory, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Dewiere, L.; Ardois, C. [IRSN, Environment and Emergency Operations Division, Geosphere-related Risk Analysis Department, BP 17, 92262 Fontenay-aux-Roses (France); Gaudet, J.P. [UMR 5564 (CNRS/IRD/INPG/UJF), LTHE, BP 53, 38041 Grenoble Cedex 9 (France)

    2005-07-01

    Full text of publication follows: While transport of non-reactive solutes has been studied extensively in unsaturated porous media, much less is known about the factors that control the transport of sorbing solutes in unsaturated conditions. Three laboratory techniques were used to analyze the transport of Sr in the aeolian sand from Chernobyl Pilot Site [1] in both saturated and unsaturated flow conditions. Batch experiments were performed to study the chemical equilibrium state of the soil/solution system. Stirred flow-through reactor (SFTR) experiments were performed to study the kinetics and reversibility of sorption reactions at the surface of solid particles. Column experiments were also performed in saturated and unsaturated steady flow conditions. Experimental data pointed out a non-linear, instantaneous and reversible sorption process of Sr. A suitable cation-exchange model was used to describe the solute/soil reaction. The former model was coupled with transport models to describe behavior of Sr in saturated [2] and unsaturated flow conditions. Transport properties of sand packed columns have been determined with an inert tracer (HTO). BTCs obtained under saturated conditions exhibit a small amount of dispersion compared to those obtained under unsaturated conditions. Classical advection-dispersion model described successfully saturated tritium breakthrough curves (BTCs), whereas a mobile-immobile model (MIM) was required to described asymmetrical unsaturated BTCs. The MIM assumes that the porous medium contains a mobile water phase in which convective-dispersive transport occurs, and a immobile water phase with which solutes can exchange with a first order kinetic. In our experiments, transport by advection in the mobile phase is the predominant process whatever the flow conditions and mass transfer rate between the mobile and immobile regions is the predominant process for broadening the BTCs. Since dispersion is blurred by mass transfer resistance, the

  6. Geophysical Methods for Investigating Ground-Water Recharge

    Science.gov (United States)

    Ferre, Ty P.A.; Binley, Andrew M.; Blasch, Kyle W.; Callegary, James B.; Crawford, Steven M.; Fink, James B.; Flint, Alan L.; Flint, Lorraine E.; Hoffmann, John P.; Izbicki, John A.; Levitt, Marc T.; Pool, Donald R.; Scanlon, Bridget R.

    2007-01-01

    While numerical modeling has revolutionized our understanding of basin-scale hydrologic processes, such models rely almost exclusively on traditional measurements?rainfall, streamflow, and water-table elevations?for calibration and testing. Model calibration provides initial estimates of ground-water recharge. Calibrated models are important yet crude tools for addressing questions about the spatial and temporal distribution of recharge. An inverse approach to recharge estimation is taken of necessity, due to inherent difficulties in making direct measurements of flow across the water table. Difficulties arise because recharging fluxes are typically small, even in humid regions, and because the location of the water table changes with time. Deep water tables in arid and semiarid regions make recharge monitoring especially difficult. Nevertheless, recharge monitoring must advance in order to improve assessments of ground-water recharge. Improved characterization of basin-scale recharge is critical for informed water-resources management. Difficulties in directly measuring recharge have prompted many efforts to develop indirect methods. The mass-balance approach of estimating recharge as the residual of generally much larger terms has persisted despite the use of increasing complex and finely gridded large-scale hydrologic models. Geophysical data pertaining to recharge rates, timing, and patterns have the potential to substantially improve modeling efforts by providing information on boundary conditions, by constraining model inputs, by testing simplifying assumptions, and by identifying the spatial and temporal resolutions needed to predict recharge to a specified tolerance in space and in time. Moreover, under certain conditions, geophysical measurements can yield direct estimates of recharge rates or changes in water storage, largely eliminating the need for indirect measures of recharge. This appendix presents an overview of physically based, geophysical methods

  7. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

    Full Text Available Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination.

  8. Transportation

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Here is the decree of the thirtieth of July 1998 relative to road transportation, to trade and brokerage of wastes. It requires to firms which carry out a road transportation as well as to traders and to brokers of wastes to declare their operations to the prefect. The declaration has to be renewed every five years. (O.M.)

  9. Strategy for the use of laboratory methods in the site investigations programme for the transport properties of the rock

    International Nuclear Information System (INIS)

    Widestrand, Henrik; Byegaard, Johan; Ohlsson, Yvonne; Tullborg, Eva-Lena

    2003-06-01

    This report comprises a strategy for the handling of laboratory investigations of diffusivity and sorption characteristics within the discipline-specific programme 'Transport Properties of the Rock' in the SKB site investigations. The aim of the transport programme is to investigate the solute transport properties at a site in order to acquire data that are required for an assessment of the long-term performance and radiological safety of the deep repository. The result of the transport programme is the Transport Properties Site Descriptive Model, i.e. a description of the site-specific properties for the transport of solutes in the groundwater at a site. A strategy for the methodology, control of sampling and characterisation programme and interpretation of the results, is proposed. The basis for the laboratory investigations is a conceptual geological model based on the geological model produced in the geology programme. Major and minor types of rock and fractures are defined and characterised according to the quality of the general database and site-specific needs. The selection of samples and analyses is determined in close co-operation with the geology, hydrogeology, hydrogeochemistry and rock mechanics programmes. The result of the laboratory investigations is a retardation model, which is used as an input in the Transport Properties Site Descriptive Model. The interpretation and production of a retardation model is described and exemplified. Lastly, method-specific strategies and recommendations are given, including strategies for the selection of tracers in the experiments and for the treatment of the sampled geologic materials

  10. A preliminary investigation of the water use efficiency of sweet ...

    African Journals Online (AJOL)

    2016-01-01

    Jan 1, 2016 ... fresh stalk biomass (t∙ha-1) × 10 × 0.511 (conversion factor of ethanol from sugar) × 0.85 (total ... (Brix) yield to seasonal water use. Ethanol. WUE was also estimated as the ratio of ethanol yield to sea- .... at Ukulinga was 24.4 t∙ha−1 with a standard deviation (SD) of. 3.4(%)t∙ha−1 for the 2010/11 growing ...

  11. Investigation of Locally Made Ceramic Filter for Household Water Treatment

    Directory of Open Access Journals (Sweden)

    Awaluddin Nurmiyanto

    2012-06-01

    Full Text Available This research have objective to develop and evaluate the performance of ceramic filter in using locally available material at Yogyakarta. Ceramic filter are made by pressing a mixture of clay, discarded pottery (grog and combustible material (coconut fiber into the molder. Curving processes are then applied to form tubular shape before firing it using kiln (1005°C. Filtration test were performed gravitationally by flowing well water into ceramic filter. Filtered water quality was complying with Indonesia drinking water quality standard (E.Coli and turbidity although it has low filtration rate (0,461 L/Hr. The most optimum ceramic filter in turbidity and bacterial removal was composition number 10 {clay+coconut fiber 4,5%(w/w+grog 5%(w/w} that have average turbidity removal 88,2%, and average E. Coli removal 100%. N2 adsorption-desorption result on ceramic filter number 10 showed 0,04μm pore size, and 4,32m2/g pore surface area. The result from the XRD (X-ray diffractometer indicates crystal structure of calcite and quartz on ceramic filter surface. Energy Dispersive X-ray (EDX analysis showed Carbon compound as the most material constituent within the filter. Whereas micro’s photo using SEM (scanning electron microscopic and TEM (transmitted electron microscopic showed filter surface consists of stacked aggregates, separated by more randomly oriented particles.

  12. Multiangular hyperspectral investigation of polarized light in case 2 waters

    Science.gov (United States)

    Tonizzo, A.; Zhou, J.; Gilerson, A.; Chowdhary, J.; Gross, B.; Moshary, F.; Ahmed, S.

    2009-09-01

    The focus of this work is on the dependence of in situ hyperspectral and multiangular polarized data on the size distribution and refractive index of the suspended particles. Underwater polarization measurements were obtained using a polarimeter developed at the Optical Remote Sensing Laboratory of the City College of New York, NY. The degree of polarization (DOP) of the underwater light field in coastal environments was measured and the water-leaving polarized radiance was derived. In-water optical properties were also measured with an ac-9 (WET Labs). Absorption and attenuation spectra are then used to derive information on the dissolved and suspend components in the water medium which are used in a vector radiative transfer code which provides the upwelling radiance. The model was run for various values of the refractive index of mineral particles until the modeled DOP matched the measured one. The relationship between the intensity of the maximum of the DOP and both the refractive index of the mineral particles and the shapes of their size distributions is analyzed in detail.

  13. Coarse-grained model of nanoscale segregation, water diffusion, and proton transport in Nafion membranes

    Science.gov (United States)

    Vishnyakov, Aleksey; Mao, Runfang; Lee, Ming-Tsung; Neimark, Alexander V.

    2018-01-01

    We present a coarse-grained model of the acid form of Nafion membrane that explicitly includes proton transport. This model is based on a soft-core bead representation of the polymer implemented into the dissipative particle dynamics (DPD) simulation framework. The proton is introduced as a separate charged bead that forms dissociable Morse bonds with water beads. Morse bond formation and breakup artificially mimics the Grotthuss hopping mechanism of proton transport. The proposed DPD model is parameterized to account for the specifics of the conformations and flexibility of the Nafion backbone and sidechains; it treats electrostatic interactions in the smeared charge approximation. The simulation results qualitatively, and in many respects quantitatively, predict the specifics of nanoscale segregation in the hydrated Nafion membrane into hydrophobic and hydrophilic subphases, water diffusion, and proton mobility. As the hydration level increases, the hydrophilic subphase exhibits a percolation transition from a collection of isolated water clusters to a 3D network of pores filled with water embedded in the hydrophobic matrix. The segregated morphology is characterized in terms of the pore size distribution with the average size growing with hydration from ˜1 to ˜4 nm. Comparison of the predicted water diffusivity with the experimental data taken from different sources shows good agreement at high and moderate hydration and substantial deviation at low hydration, around and below the percolation threshold. This discrepancy is attributed to the dynamic percolation effects of formation and rupture of merging bridges between the water clusters, which become progressively important at low hydration, when the coarse-grained model is unable to mimic the fine structure of water network that includes singe molecule bridges. Selected simulations of water diffusion are performed for the alkali metal substituted membrane which demonstrate the effects of the counter-ions on

  14. Investigation of selected water quality parameters in the Amargosa Drainage Basin

    International Nuclear Information System (INIS)

    Elliott, B.

    1982-08-01

    The purpose of this investigation was to determine whether Amargoso Desert water quality meets established federal drinking water standards. Samples were collected at selected drinking water supply sites and were analyzed for inorganic chemical constituents and radioactivity. The findings indicate that no concentrations of radioactivity in the drinking water exceeded the standards; however, some naturally occurring chemical constituent analysis indicate concentrations above federal drinking water standards. 18 references, 3 figures, 4 tables. (MF)

  15. Aespoe HRL - Geoscientific evaluation 1997/4. Results from pre-investigation and detailed site characterization. Comparison of predictions and observations. Hydrogeology, groundwater chemistry and transport of solutes

    International Nuclear Information System (INIS)

    Rhen, I.; Gustafson, Gunnar; Wikberg, P.

    1997-06-01

    The pre-investigations for the Aespoe Hard Rock Laboratory were started in 1986 and involved extensive field measurements, aimed at characterizing the rock formations with regard to geology, hydrogeology, hydrochemistry and rock mechanics. Prior to the excavation in 1990 predictions were made for the excavation phase concerning: geology, ground water flow and chemistry, transport of solutes and mechanical stability. This report presents a comparison between these predictions and the observations made during the excavation. Also, investigation methods for the 700-2874 m sections of the tunnel are evaluated

  16. Spatio-Temporal Variability of Water Vapor in the Free Troposphere Investigated by Dial and Ftir Vertical Soundings

    Science.gov (United States)

    Vogelmann, H.; Sussmann, R.; Trickl, T.; Reichert, A.

    2016-06-01

    We report on the free tropospheric spatio-temporal variability of water vapor investigated by the analysis of a five-year period of water vapor vertical soundings above Mt. Zugspitze (2962 m a.s.l., Germany). Our results are obtained from a combination of measurements of vertically integrated water vapor (IWV), recorded with a solar Fourier Transform InfraRed (FTIR) spectrometer and of water vapor profiles recorded with the nearby differential absorption lidar (DIAL). The special geometrical arrangement of one zenith-viewing and one sun-pointing instrument and the temporal resolution of both optical instruments allow for an investigation of the spatio-temporal variability of IWV on a spatial scale of less than one kilometer and on a time scale of less than one hour. We investigated the short-term variability of both IWV and water vapor profiles from statistical analyses. The latter was also examined by case studies with a clear assignment to certain atmospheric processes as local convection or long-range transport. This study is described in great detail in our recent publication [1].

  17. Spatio-Temporal Variability of Water Vapor in the Free Troposphere Investigated by Dial and Ftir Vertical Soundings

    Directory of Open Access Journals (Sweden)

    Vogelmann H.

    2016-01-01

    Full Text Available We report on the free tropospheric spatio-temporal variability of water vapor investigated by the analysis of a five-year period of water vapor vertical soundings above Mt. Zugspitze (2962 m a.s.l., Germany. Our results are obtained from a combination of measurements of vertically integrated water vapor (IWV, recorded with a solar Fourier Transform InfraRed (FTIR spectrometer and of water vapor profiles recorded with the nearby differential absorption lidar (DIAL. The special geometrical arrangement of one zenith-viewing and one sun-pointing instrument and the temporal resolution of both optical instruments allow for an investigation of the spatio-temporal variability of IWV on a spatial scale of less than one kilometer and on a time scale of less than one hour. We investigated the short-term variability of both IWV and water vapor profiles from statistical analyses. The latter was also examined by case studies with a clear assignment to certain atmospheric processes as local convection or long-range transport. This study is described in great detail in our recent publication [1].

  18. Clinical investigation on application of water swallowing to MR esophagography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinping, E-mail: zjpmri@163.com [Department of Radiology, Tongling People' s Hospital, Bijiashan Road 468, Tongling 244000, Anhui (China); Hu, Weijian; Zang, Lin [Department of Cardiothoracic Surgery, Tongling People' s Hospital, Bijiashan Road 468, Tongling 244000, Anhui (China); Yao, Yibin; Tang, Yongxiang; Qian, Zhen; Gao, Ping; Wu, Xiaoyan; Li, Shijian [Department of Radiology, Tongling People' s Hospital, Bijiashan Road 468, Tongling 244000, Anhui (China); Xie, Zhenlan; Yuan, Xiaoqing [Department of Pathology, Tongling People' s Hospital, Bijiashan Road 468, Tongling 244000, Anhui (China)

    2012-09-15

    Objective: To verify the clinical outcomes of applying water swallowing to MR esophagography. Methods: Thirty patients confirmed postoperatively or histopathologically with thoracic esophageal carcinoma by endoscopic biopsy and 10 healthy volunteers with normal esophagus underwent respectively conventional magnetic resonance imaging (MRI) detection and water swallowing MR esophagography. Of those patients, 4 underwent second examination after radiotherapy. Assessment on imaging effects of MR esophagography was performed. Assessment on definition on MR esophagography of the tumor in both upper and lower ends, specific localization, tumor size finally measured, coincidence with the gross pathologic types and tumor staging were respectively performed by comparison with conventional MRI. Additionally, we evaluated the outcomes of radiotherapy by comparing the previous MR esophagography with the second one with interventional technique. Results: Of the total 44 images of MR esophagography, 97.7% (43/44) were in high resolution by sagittal view and 81.8% (36/44) by cross-section. 93.3% (56/60) of the MR esophagography were clearly defined with the neoplastic lesion ends in the 30 patients with thoracic esophageal carcinoma, compared with 11.7% (7/60) by conventional MRI. The results were totally different in statistics (P < 0.005). Preoperative conventional MRI detection of the 22 cases in 25 undergone radical resection suggested vague diameter of the primary tumor and impossibly identified it at middle-lower thoracic esophagus in 5, and even failed to confirm gross pathologic types in 19 cases. Yet, MR esophagography with water swallowing represented accurate tumor length (graded as excellent) in 88% (22/25), localization in 100% (25/25), exact gross pathologic types in 88% (22/25), and accuracy for tumor staging in 80.8% (21/26) compared to 92.3% (24/26) by conventional MRI. Therapeutic effects achieved in 4 patients with radiotherapy. Conclusions: MR esophagography

  19. Preliminary investigation of the transport of small plastic litter along a vegetated riverbank

    Science.gov (United States)

    Liu, Da; Valyrakis, Manousos

    2017-04-01

    Plastics are widely used in consumer products, due to its low cost, low weight and high durability compared to other types of materials. Contamination of marine ecosystems due to plastics (including microplastics) is a challenge that has received a lot of attention due to the significant risks it poses for the environment and human health. Plastics find their way to the ocean from land via the river system. Studying and obtaining a better understanding of the mechanisms contributing to the fate of plastic litter is therefore important in proactively devising methods to reduce their quantity or produce designs to trap plastic pollutants and prevent them from entering the ocean through estuaries. In this context, it is a common observation of hydraulic practitioners and field geomorphologists, that plastic litter can be trapped within riparian vegetation patches along streams or canals, which can be washed away in periods of high flows. To this goal this study aims to use a series of purpose specific physical experiments to examine the mechanisms of dispersion of plastic litter along the water surface of a channel with simulated riparian vegetation. The set of experiments are conducted in a recirculating flume with rigid riverbank and riparian vegetation modeled by a large number of acrylic rods, placed on the top of the riverbank section. Six different sizes of pieces of Styrofoam are used to simulate plastic litter. These are released from different locations upstream and in the vicinity of the riparian vegetation for various configurations (linear, staggered and random) of characteristic solid density. The trajectory of the plastic litter is recorded with a camera offering a top view of the arrangement. From the analysis of this a variety of results are obtained including transport metrics (including transport velocity and time to trapping) and litter-trapping location. The relation between the size of the litter, the vegetation configuration and the traveling

  20. Water-mediated interactions enable smooth substrate transport in a bacterial efflux pump.

    Science.gov (United States)

    Vargiu, Attilio Vittorio; Ramaswamy, Venkata Krishnan; Malvacio, Ivana; Malloci, Giuliano; Kleinekathöfer, Ulrich; Ruggerone, Paolo

    2018-04-01

    Efflux pumps of the Resistance-Nodulation-cell Division superfamily confer multi-drug resistance to Gram-negative bacteria. The most-studied polyspecific transporter belonging to this class is the inner-membrane trimeric antiporter AcrB of Escherichia coli. In previous studies, a functional rotation mechanism was proposed for its functioning, according to which the three monomers undergo concerted conformational changes facilitating the extrusion of substrates. However, the molecular determinants and the energetics of this mechanism still remain unknown, so its feasibility must be proven mechanistically. A computational protocol able to mimic the functional rotation mechanism in AcrB was developed. By using multi-bias molecular dynamics simulations we characterized the translocation of the substrate doxorubicin driven by conformational changes of the protein. In addition, we estimated for the first time the free energy profile associated to this process. We provided a molecular view of the process in agreement with experimental data. Moreover, we showed that the conformational changes occurring in AcrB enable the formation of a layer of structured waters on the internal surface of the transport channel. This water layer, in turn, allows for a fairly constant hydration of the substrate, facilitating its diffusion over a smooth free energy profile. Our findings reveal a new molecular mechanism of polyspecific transport whereby water contributes by screening potentially strong substrate-protein interactions. We provided a mechanistic understanding of a fundamental process related to multi-drug transport. Our results can help rationalizing the behavior of other polyspecific transporters and designing compounds avoiding extrusion or inhibitors of efflux pumps. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  1. Stable isotope reactive transport modeling in water-rock interactions during CO2 injection

    Science.gov (United States)

    Hidalgo, Juan J.; Lagneau, Vincent; Agrinier, Pierre

    2010-05-01

    Stable isotopes can be of great usefulness in the characterization and monitoring of CO2 sequestration sites. Stable isotopes can be used to track the migration of the CO2 plume and identify leakage sources. Moreover, they provide unique information about the chemical reactions that take place on the CO2-water-rock system. However, there is a lack of appropriate tools that help modelers to incorporate stable isotope information into the flow and transport models used in CO2 sequestration problems. In this work, we present a numerical tool for modeling the transport of stable isotopes in groundwater reactive systems. The code is an extension of the groundwater single-phase flow and reactive transport code HYTEC [2]. HYTEC's transport module was modified to include element isotopes as separate species. This way, it is able to track isotope composition of the system by computing the mixing between the background water and the injected solution accounting for the dependency of diffusion on the isotope mass. The chemical module and database have been expanded to included isotopic exchange with minerals and the isotope fractionation associated with chemical reactions and mineral dissolution or precipitation. The performance of the code is illustrated through a series of column synthetic models. The code is also used to model the aqueous phase CO2 injection test carried out at the Lamont-Doherty Earth Observatory site (Palisades, New York, USA) [1]. References [1] N. Assayag, J. Matter, M. Ader, D. Goldberg, and P. Agrinier. Water-rock interactions during a CO2 injection field-test: Implications on host rock dissolution and alteration effects. Chemical Geology, 265(1-2):227-235, July 2009. [2] Jan van der Lee, Laurent De Windt, Vincent Lagneau, and Patrick Goblet. Module-oriented modeling of reactive transport with HYTEC. Computers & Geosciences, 29(3):265-275, April 2003.

  2. Water flow and multicomponent solute transport in drip-irrigated lysimeters

    Science.gov (United States)

    Raij, Iael; Šimůnek, Jiří; Ben-Gal, Alon; Lazarovitch, Naftali

    2016-08-01

    Controlled experiments and modeling are crucial components in the evaluation of the fate of water and solutes in environmental and agricultural research. Lysimeters are commonly used to determine water and solute balances and assist in making sustainable decisions with respect to soil reclamation, fertilization, or irrigation with low-quality water. While models are cost-effective tools for estimating and preventing environmental damage by agricultural activities, their value is highly dependent on the accuracy of their parameterization, often determined by calibration. The main objective of this study was to use measured major ion concentrations collected from drip-irrigated lysimeters to calibrate the variably saturated water flow model HYDRUS (2D/3D) coupled with the reactive transport model UNSATCHEM. Irrigation alternated between desalinated and brackish waters. Lysimeter drainage and soil solution samples were collected for chemical analysis and used to calibrate the model. A second objective was to demonstrate the potential use of the calibrated model to evaluate lower boundary design options of lysimeters with respect to leaching fractions determined using drainage water fluxes, chloride concentrations, and overall salinity of drainage water, and exchangeable sodium percentage (ESP) in the profile. The model showed that, in the long term, leaching fractions calculated with electrical conductivity values would be affected by the lower boundary condition pressure head, while those calculated with chloride concentrations and water fluxes would not be affected. In addition, clear dissimilarities in ESP profiles were found between lysimeters with different lower boundary conditions, suggesting a potential influence on hydraulic conductivities and flow patterns.

  3. Surface deformation induced by water pumping for construction of Mass Rapid Transportation in Taipei basin

    Science.gov (United States)

    Hu, J. C.; Wu, P. C.; Tung, H.; Tsai, M. C.

    2017-12-01

    In 1968, there were 2,200 wells in the Taipei Basin used for water supply to meet the requirement of high population density. The overuse of ground water lead to the land subsidence rate up to 5 cm/yr. Although the government had already begun to limit groundwater pumping since 1968, the groundwater in the Taipei Basin demonstrated temporary fluctuation induced by pumping water for large deep excavation site or engineering usage. The previous study based on precise leveling suggested that the surface deformation was highly associated with the recovery of water level. In 1989, widespread uplift dominated in Taipei basin due to the recovery of ground water Table. In this study, we use 37 high-resolution X-band COSMO-SkyMed radar images from May 2011 to April 2015 to characterize deformation pattern in the period of construction of Mass Rapid Transportation (MRT). We also use 30 wells and 380 benchmarks of precise leveling in Taipei basin to study the correlation of surface deformation and change of ground water table. The storability is roughly constant across most of the aquifer with values between 0.8 x 10-4 and 1.3 x 10-3. Moreover, the high water pumping in two major aquifers, Jignme and Wuku Foramtions, before the underground construction for MRT led to inflict surface deformation and no time delay observed for surface deformation during the water pumping. It implies that the poro-elastic effect dominates in major aquifers in Taipei basin.

  4. Investigation of high-p{sub T} phenomena within a partonic transport model

    Energy Technology Data Exchange (ETDEWEB)

    Fochler, Oliver

    2011-10-26

    In the work presented herein the microscopic transport model BAMPS (Boltzmann Approach to Multi-Parton Scatterings) is applied to simulate the time evolution of the hot partonic medium that is created in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) and in Pb+Pb collisions at the recently started Large Hadron Collider (LHC). The study is especially focused on the investigation of the nuclear modification factor R{sub AA}, that quantifies the suppression of particle yields at large transverse momentum with respect to a scaled proton+proton reference, and the simultaneous description of the collective properties of the medium in terms of the elliptic flow v{sub 2} within a common framework. (orig.)

  5. Investigation of Multiscale and Multiphase Flow, Transport and Reaction in Heavy Oil Recovery Processes

    Energy Technology Data Exchange (ETDEWEB)

    Yortsos, Y.C.

    2001-05-29

    This report is an investigation of various multi-phase and multiscale transport and reaction processes associated with heavy oil recovery. The thrust areas of the project include the following: Internal drives, vapor-liquid flows, combustion and reaction processes, fluid displacements and the effect of instabilities and heterogeneities and the flow of fluids with yield stress. These find respective applications in foamy oils, the evolution of dissolved gas, internal steam drives, the mechanics of concurrent and countercurrent vapor-liquid flows, associated with thermal methods and steam injection, such as SAGD, the in-situ combustion, the upscaling of displacements in heterogeneous media and the flow of foams, Bingham plastics and heavy oils in porous media and the development of wormholes during cold production.

  6. Groundwater-Surface Water Interactions and Downstream Transport of Water, Heat, and Solutes in a Hydropeaked River

    Science.gov (United States)

    Ferencz, S. B.; Cardenas, M. B.; Neilson, B. T.; Watson, J.

    2017-12-01

    A majority of the world's largest river systems are regulated by dams. In addition to being used for water resources management and flood prevention, many large dams are also used for hydroelectric power generation. In the United States, dams account for 7% of domestic electricity, and hydropower accounts for 16% of worldwide electricity production. To help meet electricity demand during peak usage times, hydropower utilities often increase their releases of water during high demand periods. This practice, termed hydropeaking, can cause large transient flow regimes downstream of hydroelectric dams. These transient flow increases can result in order of magnitude daily fluctuations in discharge, and the released water can have different thermal and chemical properties than ambient river water. As hydropeaking releases travel downstream, the temporary rise in stage and increase in discharge can enhance surface water-groundwater (SW-GW) exchange between the river and its alluvial aquifer. This dam-induced SW-GW exchange, combined with hydrodynamic attenuation and heat exchange processes, result in complex responses downstream. The dam-regulated Lower Colorado River downstream of Austin, TX was used as a natural laboratory to observe SW-GW interactions and downstream transport of water, heat, and solutes under hydropeaking conditions. To characterize SW-GW interactions, well transects were installed in the banks of the river to observe exchanges between the river and alluvial aquifer. The well transects were installed at three different distances from the dam (15km, 35km, and 80km). At each well transect conductivity, temperature, and pressure sensors were deployed in the monitoring wells and in the channel. Additional conductivity and temperature sensors were deployed along the study reach to provide a more detailed record of heat and solute transport during hydropeaking releases. The field data spans over two months of daily dam releases that were punctuated by two

  7. An investigation into the hazards associated with the maritime transport of spent nuclear reactor fuel to the British Isles

    International Nuclear Information System (INIS)

    1980-01-01

    Interim results are presented from an investigation into the potential hazard from maritime transport of spent reactor fuel. From a review of official safety studies the most severe accident is identified as a prolonged shipboard fire of 9 hours or more. According to studies performed for the International Atomic Energy Agency by the Batelle Laboratories such a fire could fail all fuel elements and release volatile radionuclides such as caesium to the environment. The consequences of such an accident are investigated for a release to the Irish Sea from a fire damaged vessel. Consequences are analysed for a release to the continental shelf waters following sinking, and also for an atmospheric release close to a conurbation. The port of Barrow is taken as an example. The report concludes that either of these events could have catastrophic consequences: the Irish Sea might have to be closed to fisheries and in the case of an atmospheric release large scale evacuation would be necessary to prevent loss of life. (author)

  8. Nanoscale Titanium Dioxide (nTiO2) Transport in Water-Saturated Natural Sediments: Influence of Soil Organic Matter and Fe/Al Oxyhydroxides

    Science.gov (United States)

    Fisher-Power, L.; Cheng, T.

    2017-12-01

    Transport of engineered nanoparticles (ENP) in subsurface environments has important implications to water quality and soil contamination. Although extensive research has been conducted to understand the effects of water chemistry on ENP transport, less attention has been paid to influences from the transport medium/matrix. The objective of this research is to investigate the effects of natural organic matter (NOM) and Fe/Al oxyhydroxides in a natural sediment on ENP transport. A sediment was collected and separated into four portions, one of which was unmodified, and the others treated to remove specific components (organic matter, Fe/Al oxyhydroxides, or both organic matter and Fe/Al oxyhydroxides). Transport of nanoscale titanium dioxide (nTiO2) in columns packed with quartz sand and each of the four types of the sediment under water-saturated conditions was studied. Our results showed that nTiO2 transport was strongly influenced by pH and sediment composition. When influent pH = 5, nTiO2 transport in all the sediments was low, as positively-charged nTiO2 was attracted to negatively charged NOM, quartz, and other minerals. nTiO2 transport was slightly enhanced in columns packed with untreated sediment or Fe/Al oxyhydroxides removed sediment due to dissolved organic matter generated by the partial dissolution of NOM, which adsorbed onto nTiO2 surface and reversed its zeta potential to negative. When influent pH = 9, nTiO2 transport was generally high since negatively-charged nTiO2 was repelled by negatively charged transport medium. However, in columns packed with the organic matter removed sediment or the Fe/Al oxyhydroxides removed sediment, nTiO2 transport was low. This was attributable to pH buffering by the sediment, which decreased pore water pH in the column, resulting in zeta potential change and electrostatic attraction between Fe/Al oxyhydroxides and nTiO2. This research demonstrates that electrostatic forces between nTiO2 and mineral/organic components

  9. FEATURES OF ADMINISTRATIVEJURISDICTIONAL ACTIVITY OF EMPLOYEES OF POLICE IN ENSURING PUBLIC SAFETY ON WATER TRANSPORT

    OpenAIRE

    L. B. Panfilova; E. A. Sychev

    2016-01-01

    The article attempts to reveal the concept of administrative and jurisdictional activity of the police to ensure public safety on water transport, the features of the stages of proceedings on administrative offenses. Under the administrative process is commonly understood outside the law enforcement activities of the executive authorities, local government agencies and other entities authorized by the state to resolve the limits of their competence in specific legal cases arising on the basis...

  10. Hollow Nanospheres with Fluorous Interiors for Transport of Molecular Oxygen in Water

    KAUST Repository

    Vu, Khanh B.

    2016-08-11

    A dispersion system for saturated fluorocarbon (SFC) liquids based on permeable hollow nanospheres with fluorous interiors is described. The nanospheres are well dispersible in water and are capable of immediate uptake of SFCs. The nanosphere shells are gas-permeable and feature reactive functional groups for easy modification of the exterior. These features make the SFC-filled nanospheres promising vehicles for respiratory oxygen storage and transport. Uptake of molecular oxygen into nanosphere-stabilized SFC dispersions is demonstrated.

  11. Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single Family Homes (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, J.; Withers, C.; Martin, E.; Moyer, N.

    2012-10-01

    This document focuses on managing the driving forces which move air and moisture across the building envelope. While other previously published Measure Guidelines focus on elimination of air pathways, the ultimate goal of this Measure Guideline is to manage drivers which cause air flow and water vapor transport across the building envelope (and also within the home), control air infiltration, keep relative humidity (RH) within acceptable limits, avoid combustion safety problems, improve occupant comfort, and reduce house energy use.

  12. Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single-Family Homes

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, James [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Withers, Charles [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Martin, Eric [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States); Moyer, Neil [Building America Partnership for Improved Residential Construction (BA-PIRC), Cocoa, FL (United States)

    2012-10-01

    This report is a revision of an earlier report titled: Measure Guideline: Managing the Drivers of Air Flow and Water Vapor Transport in Existing Single-Family Homes. Revisions include: Information in the text box on page 1 was revised to reflect the most accurate information regarding classifications as referenced in the 2012 International Residential Code. “Measure Guideline” was dropped from the title of the report. An addition was made to the reference list.

  13. Waste area Grouping 2 Phase I remedial investigation: Sediment and Cesium-137 transport modeling report

    International Nuclear Information System (INIS)

    Clapp, R.B.; Bao, Y.S.; Moore, T.D.; Brenkert, A.L.; Purucker, S.T.; Reece, D.K.; Burgoa, B.B.

    1996-06-01

    This report is one of five reports issued in 1996 that provide follow-up information to the Phase I Remedial Investigation (RI) Report for Waste Area Grouping (WAG) 2 at Oak Ridge National Laboratory (ORNL). The five reports address areas of concern that may present immediate risk to public health at the Clinch River and ecological risk within WAG 2 at ORNL. A sixth report, on groundwater, in the series documenting WAG 2 RI Phase I results were part of project activities conducted in FY 1996. The five reports that complete activities conducted as part of Phase I of the Remedial Investigation (RI) for WAG 2 are as follows: (1) Waste Area Grouping 2, Phase I Task Data Report: Seep Data Assessment, (2) Waste Area Grouping 2, Phase I Task Data Report: Tributaries Data Assessment, (3) Waste Area Grouping 2, Phase I Task Data Report: Ecological Risk Assessment, (4) Waste Area Grouping 2, Phase I Task Data Report: Human Health Risk Assessment, (5) Waste Area Grouping 2, Phase I Task Data Report: Sediment and 137 Cs Transport Modeling In December 1990, the Remedial Investigation Plan for Waste Area Grouping 2 at Oak Ridge National Laboratory was issued (ORNL 1990). The WAG 2 RI Plan was structured with a short-term component to be conducted while upgradient WAGs are investigated and remediated, and a long-term component that will complete the RI process for WAG 2 following remediation of upgradient WAGs. RI activities for the short-term component were initiated with the approval of the Environmental Protection Agency, Region IV (EPA), and the Tennessee Department of Environment and Conservation (TDEC). This report presents the results of an investigation of the risk associated with possible future releases of 137 Cs due to an extreme flood. The results are based on field measurements made during storms and computer model simulations

  14. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Flueckiger, Reto [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Marone, Federica [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stampanoni, Marco [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Institute for Biomedical Engineering, University and ETH Zurich, Gloriastrasse 35, CH-8092 Zurich (Switzerland); Wokaun, Alexander [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Buechi, Felix N., E-mail: felix.buechi@psi.c [Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2011-02-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  15. Investigation of liquid water in gas diffusion layers of polymer electrolyte fuel cells using X-ray tomographic microscopy

    International Nuclear Information System (INIS)

    Flueckiger, Reto; Marone, Federica; Stampanoni, Marco; Wokaun, Alexander; Buechi, Felix N.

    2011-01-01

    In polymer electrolyte fuel cells (PEFCs), condensation of water within the pore network of the gas diffusion layers (GDL) can influence the gas transport properties and thus reduce the electrochemical conversion rates. The use of X-ray tomographic microscopy (XTM), which allows for a resolution in the order of one micrometer is investigated for studying ex situ the local saturation in GDL's. The strength of XTM is the high spatial resolution with simultaneous contrast for water and carbon, allowing for non-destructive 3D-imaging of the solid and the contained water. The application of this method for imaging the ex situ water intrusion into the porous network of GDLs is explored using absorption and phase contrast methods. It is shown that the inhomogeneous filling behavior of GDL materials can indeed be visualized with sufficient resolution. For Toray paper TGP-H-060 the local saturation was measured as function of the water pressure. The results, evaluated in 1D, 2D and 3D show a liquid water retention effect at the denser layers near the surface. A comparison with established capillary pressure functions is presented. Altogether, the results show the potential of the XTM-method as a tool for studying the liquid water behavior in PEFC on a microscopic scale.

  16. Preliminary investigation into the cause of acid mine water induced ...

    African Journals Online (AJOL)

    An approach to risk assessment of possible earthquake scenarios in the City of Johannesburg (CoJ) is proposed. The approach aims to assess potential damage to infrastructure and loss of life in the case of an earthquake. The results of such an assessment may provide justification for more detailed investigations.

  17. Transportation

    National Research Council Canada - National Science Library

    Allshouse, Michael; Armstrong, Frederick Henry; Burns, Stephen; Courts, Michael; Denn, Douglas; Fortunato, Paul; Gettings, Daniel; Hansen, David; Hoffman, Douglas; Jones, Robert

    2007-01-01

    .... The ability of the global transportation industry to rapidly move passengers and products from one corner of the globe to another continues to amaze even those wise to the dynamics of such operations...

  18. Modeling particle transport and discoloration risk in drinking water distribution networks

    Science.gov (United States)

    van Summeren, Joost; Blokker, Mirjam

    2017-10-01

    Discoloration of drinking water is a worldwide phenomenon caused by accumulation and subsequent remobilization of particulate matter in drinking water distribution systems (DWDSs). It contributes a substantial fraction of customer complaints to water utilities. Accurate discoloration risk predictions could improve system operation by allowing for more effective programs on cleaning and prevention actions and field measurements, but are challenged by incomplete understanding on the origins and properties of particles and a complex and not fully understood interplay of processes in distribution networks. In this paper, we assess and describe relevant hydraulic processes that govern particle transport in turbulent pipe flow, including gravitational settling, bed-load transport, and particle entrainment into suspension. We assess which transport mechanisms are dominant for a range of bulk flow velocities, particle diameters, and particle mass densities, which includes common conditions for DWDSs in the Netherlands, the UK, and Australia. Our analysis shows that the theoretically predicted particle settling velocity and threshold shear stresses for incipient particle motion are in the same range as, but more variable than, previous estimates from lab experiments, field measurements, and modeling. The presented material will be used in the future development of a numerical modeling tool to determine and predict the spatial distribution of particulate material and discoloration risk in DWDSs. Our approach is aimed at understanding specific causalities and processes, which can complement data-driven approaches.

  19. Oskarshamn site investigation. Programme for further investigations of bedrock, soil, water and environment in Laxemar subarea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-03-15

    SKB (the Swedish Nuclear Fuel and Waste Management Co), has been conducting a site investigation at Simpevarp and Laxemar in Oskarshamn for siting of a final repository for spent nuclear fuel. An equivalent investigation is being conducted in Forsmark in Ohmmeter's. The initial part of the site investigations had been completed for the both of the subareas Simpevarp and Laxemar in the autumn of 2004. Based on the results of these investigations, SKB preliminarily prioritized the Laxemar subarea for further investigations. A programme was presented for the first stage of the complete site investigation in the Laxemar subarea, along with the main features of the remainder of the site investigation. The programme included investigations up until the summer of 2005 and was particularly aimed at obtaining answers to several vital questions so that the subsequent investigations could be focused on the rock areas judged to be most suitable for a final repository. These investigations have now been completed. This report presents the programme for the remainder of the site investigation. The points of departure are the general goals for the Deep Repository Project during the site investigation phase, analyses and evaluations of data from completed investigations, and the needs for additional data to be able to evaluate the site as a siting alternative for the final repository. The account mainly covers the investigations on the site. All other work - analyses, site descriptive modelling, facility design, safety assessments and studies and assessments of consequences for the environment, human health and society - are only mentioned to the extent necessary in order to place the investigations in their context. The direction of the site investigation in Oskarshamn and the investigation programme presented in this report is based on SKB's preliminary decision to prioritize the Laxemar subarea for further investigations. A final decision on the direction of the site

  20. Oskarshamn site investigation. Programme for further investigations of bedrock, soil, water and environment in Laxemar subarea

    International Nuclear Information System (INIS)

    2006-03-01

    SKB (the Swedish Nuclear Fuel and Waste Management Co), has been conducting a site investigation at Simpevarp and Laxemar in Oskarshamn for siting of a final repository for spent nuclear fuel. An equivalent investigation is being conducted in Forsmark in Ohmmeter's. The initial part of the site investigations had been completed for the both of the subareas Simpevarp and Laxemar in the autumn of 2004. Based on the results of these investigations, SKB preliminarily prioritized the Laxemar subarea for further investigations. A programme was presented for the first stage of the complete site investigation in the Laxemar subarea, along with the main features of the remainder of the site investigation. The programme included investigations up until the summer of 2005 and was particularly aimed at obtaining answers to several vital questions so that the subsequent investigations could be focused on the rock areas judged to be most suitable for a final repository. These investigations have now been completed. This report presents the programme for the remainder of the site investigation. The points of departure are the general goals for the Deep Repository Project during the site investigation phase, analyses and evaluations of data from completed investigations, and the needs for additional data to be able to evaluate the site as a siting alternative for the final repository. The account mainly covers the investigations on the site. All other work - analyses, site descriptive modelling, facility design, safety assessments and studies and assessments of consequences for the environment, human health and society - are only mentioned to the extent necessary in order to place the investigations in their context. The direction of the site investigation in Oskarshamn and the investigation programme presented in this report is based on SKB's preliminary decision to prioritize the Laxemar subarea for further investigations. A final decision on the direction of the site