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Sample records for affect water flow

  1. Nonequilibrium water dynamics in the rhizosphere: How mucilage affects water flow in soils

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The flow of water from soil to plant roots is controlled by the properties of the narrow region of soil close to the roots, the rhizosphere. In particular, the hydraulic properties of the rhizosphere are altered by mucilage, a polymeric gel exuded by the roots. In this paper we present experimental results and a conceptual model of water flow in unsaturated soils mixed with mucilage. A central hypothesis of the model is that the different drying/wetting rate of mucilage compared to the bulk soil results in nonequilibrium relations between water content and water potential in the rhizosphere. We coupled this nonequilibrium relation with the Richards equation and obtained a constitutive equation for water flow in soil and mucilage. To test the model assumptions, we measured the water retention curve and the saturated hydraulic conductivity of sandy soil mixed with mucilage from chia seeds. Additionally, we used neutron radiography to image water content in a layer of soil mixed with mucilage during drying and wetting cycles. The radiographs demonstrated the occurrence of nonequilibrium water dynamics in the soil-mucilage mixture. The experiments were simulated by numerically solving the nonequilibrium model. Our study provides conceptual and experimental evidences that mucilage has a strong impact on soil water dynamics. During drying, mucilage maintains a greater soil water content for an extended time, while during irrigation it delays the soil rewetting. We postulate that mucilage exudation by roots attenuates plant water stress by modulating water content dynamics in the rhizosphere.

  2. Assessment of processes affecting low-flow water quality of Cedar Creek, west-central Illinois

    USGS Publications Warehouse

    Schmidt, Arthur R.; Freeman, W.O.; McFarlane, R.D.

    1989-01-01

    Water quality and the processes that affect dissolved oxygen, nutrient (nitrogen and phosphorus species), and algal concentrations were evaluated for a 23.8-mile reach of Cedar Creek near Galesburg, west-central Illinois, during periods of warm-weather, low-flow conditions. Water quality samples were collected and stream conditions were measured over a diel (24 hour) period on three occasions during July and August 1985. Analysis of data from the diel-sampling periods indicates that concentrations of iron, copper, manganese, phenols, and total dissolved-solids exceeded Illinois ' general-use water quality standards in some locations. Dissolved-oxygen concentrations were less than the State minimum standard throughout much of the study reach. These data were used to calibrate and verify a one-dimensional, steady-state, water quality model. The computer model was used to assess the relative effects on low-flow water quality of processes such as algal photosynthesis and respiration, ammonia oxidation, biochemical oxygen demand, sediment oxygen demand, and stream reaeration. Results from model simulations and sensitivity analysis indicate that sediment oxygen demand is the principal cause of low dissolved-oxygen concentrations in the creek. (USGS)

  3. Microbial water quality in streams as affected by high flow events

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bottom sediments in surface water sources were shown to serve as reservoirs of pathogen and indicator microorganisms. Resuspension of these sediments during the high flow events strongly modifies microbial quality of recreation and irrigation waters. Therefore, changes in microbial water quality are...

  4. Design configurations affecting flow pattern and solids accumulation in horizontal free water and subsurface flow constructed wetlands.

    PubMed

    Pedescoll, A; Sidrach-Cardona, R; Sánchez, J C; Carretero, J; Garfi, M; Bécares, E

    2013-03-01

    The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix. PMID:23286990

  5. Hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction, San Joaquin Valley, California

    USGS Publications Warehouse

    Sneed, Michelle

    2001-01-01

    This report summarizes hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction in the San Joaquin Valley, a broad alluviated intermontane structural trough that constitutes the southern two-thirds of the Central Valley of California. These values will be used to constrain a coupled ground-water flow and aquifer-system compaction model of the western San Joaquin Valley called WESTSIM. A main objective of the WESTSIM model is to evaluate potential future land subsidence that might occur under conditions in which deliveries of imported surface water for agricultural use are reduced and ground-water pumping is increased. Storage values generally are components of the total aquifer-system storage and include inelastic and elastic skeletal storage values of the aquifers and the aquitards that primarily govern the potential amount of land subsidence. Vertical hydraulic conductivity values generally are for discrete thicknesses of sediments, usually aquitards, that primarily govern the rate of land subsidence. The data were compiled from published sources and include results of aquifer tests, stress-strain analyses of borehole extensometer observations, laboratory consolidation tests, and calibrated models of aquifer-system compaction.

  6. Modeling coupled water flow, solute transport and geochemical reactions affecting heavy metal migration in a podzol soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many or most subsurface pollution problems at the field scale involve such simultaneous processes as water flow, multicomponent solute transport, heat transport and biogeochemical processes and reactions. Process-based models that integrate these various processes can be valuable tools for investiga...

  7. How Do Changes to the Railroad Causeway in Utah’s Great Salt Lake Affect Water and Salt Flow?

    PubMed Central

    White, James S.; Null, Sarah E.; Tarboton, David G.

    2015-01-01

    Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah’s Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey’s Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses. PMID:26641101

  8. How Do Changes to the Railroad Causeway in Utah's Great Salt Lake Affect Water and Salt Flow?

    PubMed

    White, James S; Null, Sarah E; Tarboton, David G

    2015-01-01

    Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah's Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey's Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses. PMID:26641101

  9. Evaluation of the surface-water sampling design in the Western Lake Michigan Drainages in relation to environmental factors affecting water quality at base flow

    USGS Publications Warehouse

    Robertson, Dale M.

    1998-01-01

    The variability in water quality throughout the WMIC Study Unit during base-flow conditions could be described very well by subdividing the area into Relatively Homogeneous Units and sampling a few streams with drainage basins completely within these homogeneous units. This subdivision and sampling scheme enabled the differences in water quality to be directly related to the differences in the environmental characteristics that exist throughout the Study Unit.

  10. Computeer-based decision support tools for evaluation of actions affecting flow and water quality in the San Joaquin Basin

    SciTech Connect

    Quinn, N.W.T.

    1993-01-01

    This document is a preliminary effort to draw together some of the important simulation models that are available to Reclamation or that have been developed by Reclamation since 1987. This document has also attempted to lay out a framework by which these models might be used both for the purposes for which they were originally intended and to support the analysis of other issues that relate to the hydrology and to salt and water quality management within the San Joaquin Valley. To be successful as components of a larger Decision Support System the models should to be linked together using custom designed interfaces that permit data sharing between models and that are easy to use. Several initiatives are currently underway within Reclamation to develop GIS - based and graphics - based decision support systems to improve the general level of understanding of the models currently in use, to standardize the methodology used in making planning and operations studies and to permit improved data analysis, interpretation and display. The decision support systems should allow greater participation in the planning process, allow the analysis of innovative actions that are currently difficult to study with present models and should lead to better integrated and more comprehensive plans and policy decisions in future years.

  11. Evaluation of processes affecting 1,2-dibromo-3-chloropropane (DBCP) concentrations in ground water in the eastern San Joaquin Valley, California : analysis of chemical data and ground-water flow and transport simulations

    USGS Publications Warehouse

    Burow, Karen R.; Panshin, Sandra Y.; Dubrovsky, Neil H.; Vanbrocklin, David; Fogg, Graham E.

    1999-01-01

    A conceptual two-dimensional numerical flow and transport modeling approach was used to test hypotheses addressing dispersion, transformation rate, and in a relative sense, the effects of ground- water pumping and reapplication of irrigation water on DBCP concentrations in the aquifer. The flow and transport simulations, which represent hypothetical steady-state flow conditions in the aquifer, were used to refine the conceptual understanding of the aquifer system rather than to predict future concentrations of DBCP. Results indicate that dispersion reduces peak concentrations, but this process alone does not account for the apparent decrease in DBCP concentrations in ground water in the eastern San Joaquin Valley. Ground-water pumping and reapplication of irrigation water may affect DBCP concentrations to the extent that this process can be simulated indirectly using first-order decay. Transport simulation results indicate that the in situ 'effective' half-life of DBCP caused by processes other than dispersion and transformation to BAA could be on the order of 6 years.

  12. Internal Surface Water Flows

    USGS Publications Warehouse

    Murray, Mitchell H.

    1999-01-01

    Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making.The U.S. Geological Survey (USGS) provides scientitic information as part of the South Florida Ecosystem Restoration Program. The USGS began its own project, called the South Florida Ecosystem Project in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Historical changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system with canals, levees, and pumping stations. These structures have altered the hydology of the Everglades ecosystem on both coastal and interior lands. Surface-water flows in a direction south of Lake Okeechobee have been regulated by an extensive canal network, begun in the 1940's, to provide for drainage, flood control, saltwater intrusion control, agricultural requirements, and various environmental needs. Much of the development and subsequent monitoring of canal and river discharge south of Lake Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has been placed on providing a more accurate water budget for internal canal flows.

  13. The Dynamics of Flowing Waters.

    ERIC Educational Resources Information Center

    Mattingly, Rosanna L.

    1987-01-01

    Describes a series of activities designed to help students understand the dynamics of flowing water. Includes investigations into determining water discharge, calculating variable velocities, utilizing flood formulas, graphing stream profiles, and learning about the water cycle. (TW)

  14. FAITH Water Channel Flow Visualization

    NASA Video Gallery

    Water channel flow visualization experiments are performed on a three dimensional model of a small hill. This experiment was part of a series of measurements of the complex fluid flow around the hi...

  15. Bromide affecting drinking water mutagenicity.

    PubMed

    Myllykangas, T; Nissinen, T K; Mäki-Paakkanen, J; Hirvonen, A; Vartiainen, T

    2003-11-01

    The effect of bromide on the mutagenicity of artificially recharged groundwater and purified artificially recharged groundwater after chlorine, ozone, hydrogen peroxide, permanganate, and UV treatments alone and in various combinations was studied. The highest mutagenicity was observed after chlorination, while hydrogen peroxide-ozone-chlorine treatment produced the lowest value for both waters. Chlorinated waters, which were spiked with bromide, had up to 3.7 times more mutagenic activity than waters without bromide after every preoxidation method. 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) was found to correspond as much as 76% of the overall mutagenicity in the waters not spiked with bromide. MX formation was found to be lower when the treated water contained bromide, implicating the formation of brominated MX analogues. Trihalomethane formation increased when the treated water contained bromide. PMID:13129514

  16. Exploring Online Game Players' Flow Experiences and Positive Affect

    ERIC Educational Resources Information Center

    Chiang, Yu-Tzu; Lin, Sunny S. J.; Cheng, Chao-Yang; Liu, Eric Zhi-Feng

    2011-01-01

    The authors conducted two studies to explore online game players' flow experiences and positive affect. Our findings indicated that online game are capable of evoking flow experiences and positive affect, and games of violent or nonviolent type may not arouse players' aggression. The players could be placed into four flow conditions: flow,…

  17. Groundwater flow and hydrochemistry in mountain areas affected by DSGSDs

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni B.; Frattini, Paolo; Pena Reyes, Fredy; Riva, Federico

    2014-05-01

    Large slope instabilities such as DSGSD and rockslides locally affect the groundwater flow at the slope scale. These phenomena present morphostructures (scarps, counterscarps and trenches) parallel to the slope direction that control the surface water runoff, directing it transversal to the slope dip and favouring its percolation within the slope through the more conductive materials aligned with the trench . This also affects the slope hydrochemistry, locally controlling the solute transport and circulation. The upper Valtellina (Central European Alps, Northern Italy) is characterize by a high density of DSGSD phenomena, with 29 DSGSDs within an area of about 900 km2 (Crosta et al, 2013). The study area ranges from 1150 to 3500 m in altitude, and shows a clear glacial imprint, which significantly influenced the geomorphology and water distribution in the study area. In order to characterize the groundwater flow and the hydrochemistry of the area, we collected historical data analysis (4070 samples from springs, wells, lakes, rivers and public fountains), and we performed four seasonal campaigns, from summer 2012 to spring 2013, to complete a hydrologic year. During these campaigns, we measured the spring discharge, and we collected samples for chemical (anions and cations) and isotopic (tritium, deuterium and O18) analyses in more almost 40 selected spring located throughout the study area. These springs were selected because representative of main spring clusters, with a particular attention to problems related to the presence of Arsenic in high concentration. In this study, we analyze the effect of DSGSD phenomena on the aquifers of upper Valtellina through the quantitative analysis of hydro-chemical and isotopic data. We show how these phenomena affect the ground water flow also in relation to the presence of geological structures that are associated and locally reactivated by DSGSDs.

  18. Electromanipulating water flow in nanochannels.

    PubMed

    Kou, Jianlong; Yao, Jun; Lu, Hangjun; Zhang, Bo; Li, Aifen; Sun, Zhixue; Zhang, Jianguang; Fang, Yunzhang; Wu, Fengmin; Fan, Jintu

    2015-02-16

    In sharp contrast to the prevailing view that a stationary charge outside a nanochannel impedes water permeation across the nanochannel, molecular dynamics simulations show that a vibrational charge outside the nanochannel can promote water flux. In the vibrational charge system, a decrease in the distance between the charge and the nanochannel leads to an increase in the water net flux, which is contrary to that of the fixed-charge system. The increase in net water flux is the result of the vibrational charge-induced disruption of hydrogen bonds when the net water flux is strongly affected by the vibrational frequency of the charge. In particular, the net flux is reaches a maximum when the vibrational frequency matches the inherent frequency of hydrogen bond inside the nanochannel. This electromanipulating transport phenomenon provides an important new mechanism of water transport confined in nanochannels. PMID:25582712

  19. Water chemistry affects catfish susceptibility to columnaris

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While columnaris disease has been well-studied, little is known about how specific water chemistries can affect attachment. Recent studies in our labs offer new insight on this subject. Well waters from the USDA/ARS Stuttgart National Aquaculture Research Center (SNARC; Stuttgart, Arkansas) and fr...

  20. Water hardness affects catfish susceptibility to columnaris

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Columnaris disease can cause tremendous losses of freshwater fish. While it has been studied exhaustively, little is known about its affinity to specific water chemistries that affects attachment. Recent studies in our labs have illuminated this subject. In the first experiment, two waters were ...

  1. Vestibular stimulation affects optic-flow sensitivity.

    PubMed

    Edwards, Mark; O'Mahony, Simon; Ibbotson, Michael R; Kohlhagen, Stuart

    2010-01-01

    Typically, multiple cues can be used to generate a particular percept. Our area of interest is the extent to which humans are able to synergistically combine cues that are generated when moving through an environment. For example, movement through the environment leads to both visual (optic-flow) and vestibular stimulation, and studies have shown that non-human primates are able to combine these cues to generate a more accurate perception of heading than can be obtained with either cue in isolation. Here we investigate whether humans show a similar ability to synergistically combine optic-flow and vestibular cues. This was achieved by determining the sensitivity to optic-flow stimuli while physically moving the observer, and hence producing a vestibular signal, that was either consistent with the optic-flow signal, eg a radially expanding pattern coupled with forward motion, or inconsistent with it, eg a radially expanding pattern with backward motion. Results indicate that humans are more sensitive to motion-in-depth optic-flow stimuli when they are combined with complementary vestibular signals than when they are combined with conflicting vestibular signals. These results indicate that in humans, like in nonhuman primates, there is perceptual integration of visual and vestibular signals. PMID:21180352

  2. Laminar and Turbulent Flow in Water

    ERIC Educational Resources Information Center

    Riveros, H. G.; Riveros-Rosas, D.

    2010-01-01

    There are many ways to visualize flow, either for laminar or turbulent flows. A very convincing way to show laminar and turbulent flows is by the perturbations on the surface of a beam of water coming out of a cylindrical tube. Photographs, taken with a flash, show the nature of the flow of water in pipes. They clearly show the difference between…

  3. Historical Dates of Ice-Affected Flows for 18 Rivers in New England

    USGS Publications Warehouse

    Hodgkins, Glenn A.; Caldwell, James M.; Dudley, Robert W.

    2003-01-01

    Historical dates of ice-affected flows for 18 rivers in New England were compiled and are presented in this report. The length of this record for the rivers ranges from 48 to 71 years, with an average of 62 years. The minimum number of days of ice-affected flow in a water year (October 1 to September 30) ranged from zero on three rivers in south-coastal Maine and coastal New Hampshire to 110 on the Allagash River in northern Maine. The maximum number of days of ice-affected flow in a water year ranged from 106 on the Royal River in south-coastal Maine to 171 on the Allagash River in northern Maine. Six streamflow-< gaging stations in Maine, New Hampshire, and Vermont had their latest days of ice-affected flow in the spring of 1939.

  4. Factors affecting water quality in Cherokee Reservoir

    SciTech Connect

    Iwanski, M.L.; Higgins, J.M.; Kim, B.R.; Young, R.C.

    1980-07-01

    The purpose was to: (1) define reservoir problems related to water quality conditions; (2) identify the probable causes of these problems; and (3) recommend procedures for achieving needed reservoir water quality improvements. This report presents the project findings to date and suggests steps for upgrading the quality of Cherokee Reservoir. Section II presents background information on the characteristics of the basin, the reservoir, and the beneficial uses of the reservoir. Section III identifies the impacts of existing reservoir water quality on uses of the reservoir for water supply, fishery resources, recreation, and waste assimilation. Section IV presents an assessment of cause-effect relationships. The factors affecting water quality addressed in Section IV are: (1) reservoir thermal stratification and hydrodynamics; (2) dissolved oxygen depletion; (3) eutrophication; (4) toxic substances; and (5) reservoir fisheries. Section V presents a preliminary evaluation of alternatives for improving the quality of Cherokee Reservoir. Section VI presents preliminary conclusions and recommendations for developing and implementing a reservoir water quality management plan. 7 references, 22 figures, 21 tables.

  5. Determinants of virtual water flows in the Mediterranean.

    PubMed

    Fracasso, Andrea; Sartori, Martina; Schiavo, Stefano

    2016-02-01

    The aim of the paper is to investigate the main determinants of the bilateral virtual water (water used in the production of a commodity or service) flows associated with international trade in agricultural goods across the Mediterranean basin. We consider the bilateral gross flows of virtual water in the area and study what export-specific and import-specific factors are significantly associated with virtual water flows. We follow a sequential approach. Through a gravity model of trade, we obtain a "refined" version of the variable we aim to explain, one that is free of the amount of flows due to pair-specific factors affecting bilateral trade flows and that fully reflects the impact of country-specific determinants of virtual water trade. A number of country-specific potential explanatory variables, ranging from water endowments to trade barriers, from per capita GDP to irrigation prices, is presented and tested. To identify the variables that help to explain the bilateral flows of virtual water, we adopt a model selection procedure based on model averaging. Our findings confirm one of the main controversial results in the literature: larger water endowments do not necessarily lead to a larger 'export' of virtual water, as one could expect. We also find some evidence that higher water irrigation prices reduce (increase) virtual water 'exports' ('imports'). PMID:25708715

  6. Echo-acoustic flow affects flight in bats.

    PubMed

    Kugler, Kathrin; Greiter, Wolfgang; Luksch, Harald; Firzlaff, Uwe; Wiegrebe, Lutz

    2016-06-15

    Flying animals need to react fast to rapid changes in their environment. Visually guided animals use optic flow, generated by their movement through structured environments. Nocturnal bats cannot make use of optic flow, but rely mostly on echolocation. Here, we show that bats exploit echo-acoustic flow to negotiate flight through narrow passages. Specifically, bats' flight between lateral structures is significantly affected by the echo-acoustic salience of those structures, independent of their physical distance. This is true even though echolocation, unlike vision, provides explicit distance cues. Moreover, the bats reduced the echolocation sound levels in stronger flow, probably to compensate for the increased summary target strength of the lateral reflectors. However, bats did not reduce flight velocity under stronger echo-acoustic flow. Our results demonstrate that sensory flow is a ubiquitous principle for flight guidance, independent of the fundamentally different peripheral representation of flow across the senses of vision and echolocation. PMID:27045094

  7. The effect of pore water pressure on debris flow dynamics

    NASA Astrophysics Data System (ADS)

    Okura, Y.; Parker, G.; Marr, J. G.; Yu, B.; Ochiai, H.

    2003-12-01

    Pore-water likely plays an important role to reduce shear force in debris flow. In experiments, we observed pore-water pressure during flow to clarify the relationship between the flow speed and pore water pressure which would be affected by flow depth and particle size distribution. Soil materials were prepared with mixing materials of sand, silt and clay. Pore-water pressure on the flume bed, flow depth, velocity and run out distance was observed, and the following results were quantitatively obtained in this series of experiments. 1. A positive relation was observed between strain rate and pore-water pressure ratio in the flow. The strain rate and pressure ratio were dimensionless parameters of the ratios of surface velocity to flow depth and pore-water pressure head to flow depth, respectively. This relationship indicated that shear resistance decreased as the pressure potential leading to acceleration of flow velocity increased. 2. A positive relation was also observed between flow depth and pore-water pressure ratio. This indicated that the pore pressure diffusion became increasingly obstructed as the flow depth increased. 3. The pore-water pressure ratio tended to increase with the uniformity coefficient of debris flow materials. The reason for this might have been that smaller particles suspended in the flow increased pore-water pressure, and the wider range of particle distribution effectively prevented pore-water pressure diffusion. 4. There was an apparently negative correlation between the equivalent coefficient of frictions and the pressure ratios. Equivalent friction is apparent friction during flow. The most likely reason for this is that shear resistance would decrease and run out distance increase as the pressure ratio increased. These results indicated that the effect of pore water fluctuations should be one of the most important factors affecting the shear resistance in debris flows. This work was supported by the National Science Foundation

  8. Estimated Water Flows in 2005: United States

    SciTech Connect

    Smith, C A; Belles, R D; Simon, A J

    2011-03-16

    Flow charts depicting water use in the United States have been constructed from publicly available data and estimates of water use patterns. Approximately 410,500 million gallons per day of water are managed throughout the United States for use in farming, power production, residential, commercial, and industrial applications. Water is obtained from four major resource classes: fresh surface-water, saline (ocean) surface-water, fresh groundwater and saline (brackish) groundwater. Water that is not consumed or evaporated during its use is returned to surface bodies of water. The flow patterns are represented in a compact 'visual atlas' of 52 state-level (all 50 states in addition to Puerto Rico and the Virgin Islands) and one national water flow chart representing a comprehensive systems view of national water resources, use, and disposition.

  9. Mechanisms affecting water quality in an intermittent piped water supply.

    PubMed

    Kumpel, Emily; Nelson, Kara L

    2014-01-01

    Drinking water distribution systems throughout the world supply water intermittently, leaving pipes without pressure between supply cycles. Understanding the multiple mechanisms that affect contamination in these intermittent water supplies (IWS) can be used to develop strategies to improve water quality. To study these effects, we tested water quality in an IWS system with infrequent and short water delivery periods in Hubli-Dharwad, India. We continuously measured pressure and physicochemical parameters and periodically collected grab samples to test for total coliform and E. coli throughout supply cycles at 11 sites. When the supply was first turned on, water with elevated turbidity and high concentrations of indicator bacteria was flushed out of pipes. At low pressures (<10 psi), elevated indicator bacteria were frequently detected even when there was a chlorine residual, suggesting persistent contamination had occurred through intrusion or backflow. At pressures between 10 and 17 psi, evidence of periodic contamination suggested that transient intrusion, backflow, release of particulates, or sloughing of biofilms from pipe walls had occurred. Few total coliform and no E. coli were detected when water was delivered with a chlorine residual and at pressures >17 psi. PMID:24459990

  10. Agricultural Virtual Water Flows in the USA

    NASA Astrophysics Data System (ADS)

    Konar, M.; Dang, Q.; Lin, X.

    2014-12-01

    Global virtual water trade is an important research topic that has yielded several interesting insights. In this paper, we present a comprehensive assessment of virtual water flows within the USA, a country with global importance as a major agricultural producer and trade power. This is the first study of domestic virtual water flows based upon intra-national food flow data and it provides insight into how the properties of virtual water flows vary across scales. We find that both the value and volume of food flows within the USA are roughly equivalent to half that of international flows. However, USA food flows are more water intensive than international food trade, due to the higher fraction of water-intensive meat trade within the USA. The USA virtual water flow network is more social, homogeneous, and equitable than the global virtual water trade network, although it is still not perfectly equitable. Importantly, a core group of U.S. States is central to the network structure, indicating that both domestic and international trade may be vulnerable to disruptive climate or economic shocks in these U.S. States.

  11. Ground Water Flow No Longer A Mystery

    ERIC Educational Resources Information Center

    Lehr, Jay H.; Pettyjohn, Wayne A.

    1976-01-01

    Examined are the physical characteristics of ground water movement. Some potential pollution problems are identified. Models are used to explain mathematical and hydraulic principles of flow toward a pumping well and an effluent stream, flow around and through lenticular beds, and effects of pumping on the water table. (Author/MR)

  12. Protecting environmental flows through enhanced water licensing and water markets

    NASA Astrophysics Data System (ADS)

    Erfani, T.; Binions, O.; Harou, J. J.

    2014-03-01

    To enable economically efficient future adaptation to water scarcity some countries are revising water management institutions such as water rights or licensing systems to more effectively protect ecosystems and their services. Allocating more flow to the environment though can mean less abstraction for economic production, or the inability to accommodate new entrants (diverters). Modern licensing arrangements should simultaneously enhance environmental flows and protect water abstractors who depend on water. Making new licensing regimes compatible with tradable water rights is an important component of water allocation reform. Regulated water markets can help decrease the societal cost of water scarcity whilst enforcing environmental and/or social protections. In this article we simulate water markets under a regime of fixed volumetric water abstraction licenses with fixed minimum flows or under a scalable water license regime (using water "shares") with dynamic environmental minimum flows. Shares allow adapting allocations to available water and dynamic environmental minimum flows can vary as a function of ecological requirements. We investigate how a short-term spot market manifests within each licensing regime. We use a river-basin-scale hydro-economic agent model that represents individual abstractors and can simulate a spot market under both licensing regimes. We apply this model to the Great Ouse river basin in Eastern England with public water supply, agricultural, energy and industrial water using agents. Results show the proposed shares with dynamic environmental flow licensing system protects river flows more effectively than the current static minimum flow requirements during a dry historical year, but that the total opportunity cost to water abstractors of the environmental gains is a 10 to 15% loss in economic benefits.

  13. Protecting environmental flows through enhanced water licensing and water markets

    NASA Astrophysics Data System (ADS)

    Erfani, T.; Binions, O.; Harou, J. J.

    2015-02-01

    To enable economically efficient future adaptation to water scarcity some countries are revising water management institutions such as water rights or licensing systems to more effectively protect ecosystems and their services. However, allocating more flow to the environment can mean less abstraction for economic production, or the inability to accommodate new entrants (diverters). Modern licensing arrangements should simultaneously enhance environmental flows and protect water abstractors who depend on water. Making new licensing regimes compatible with tradable water rights is an important component of water allocation reform. Regulated water markets can help decrease the societal cost of water scarcity whilst enforcing environmental and/or social protections. In this article we simulate water markets under a regime of fixed volumetric water abstraction licenses with fixed minimum flows or under a scalable water license regime (using water "shares") with dynamic environmental minimum flows. Shares allow adapting allocations to available water and dynamic environmental minimum flows vary as a function of ecological requirements. We investigate how a short-term spot market manifests within each licensing regime. We use a river-basin-scale hydroeconomic agent model that represents individual abstractors and can simulate a spot market under both licensing regimes. We apply this model to the Great Ouse River basin in eastern England with public water supply, agricultural, energy and industrial water-using agents. Results show the proposed shares with dynamic environmental flow licensing system protects river flows more effectively than the current static minimum flow requirements during a dry historical year, but that the total opportunity cost to water abstractors of the environmental gains is a 10-15% loss in economic benefits.

  14. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    USGS Publications Warehouse

    : Belcher, Wayne R., (Edited By)

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were

  15. Fibre persistence on immersed garment - Influence of water flow and stay in running water.

    PubMed

    Lepot, L; Vanden Driessche, T

    2015-12-01

    The persistence of fibre traces is a critical factor in the evaluation of fibre findings in forensic casework. Water can play a major role in affecting fibre persistence as a lot of fibre traces can get lost after washing incriminated garments, after rainfall over the victim's body or after immersion of the victim in water. The influence of immersion in standing water on fibre persistence was previously studied in our laboratory on various knitted recipient fabrics. The present study is focused on the persistence of target fibres on immersed cotton T-shirts through an immersion/stay/emersion process in running water (from 1h up to 7h), simulated in laboratory (~0.4l/s, gentle water flow conditions) and in real conditions (~2000l/s, medium water flow conditions). A gentle water flow slightly affects fibre persistence, which remains more or less constant over time, regardless of the duration of the stay in water. No rapid loss is observed during immersion in real conditions, including a medium water flow and boat activity. The fibre persistence in running water seems to depend mainly on the immersion step and also, in case of a medium water flow, on the stay in water with a linear loss over hours. PMID:26654078

  16. Pressurized water reactor flow skirt apparatus

    DOEpatents

    Kielb, John F.; Schwirian, Richard E.; Lee, Naugab E.; Forsyth, David R.

    2016-04-05

    A pressurized water reactor vessel having a flow skirt formed from a perforated cylinder structure supported in the lower reactor vessel head at the outlet of the downcomer annulus, that channels the coolant flow through flow holes in the wall of the cylinder structure. The flow skirt is supported at a plurality of circumferentially spaced locations on the lower reactor vessel head that are not equally spaced or vertically aligned with the core barrel attachment points, and the flow skirt employs a unique arrangement of hole patterns that assure a substantially balanced pressure and flow of the coolant over the entire underside of the lower core support plate.

  17. How processing digital elevation models can affect simulated water budgets

    USGS Publications Warehouse

    Kuniansky, E.L.; Lowery, M.A.; Campbell, B.G.

    2009-01-01

    For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation of the water table used in model cells is estimated via a two-step process. First, a regression equation is developed using existing land and water table elevations from wells in the area. This equation is then used to predict the water table surface for each model cell using land surface elevation available from digital elevation models (DEM). Two methods of processing DEM for estimating the land surface for each cell are commonly used (value nearest the cell centroid or mean value in the cell). This article demonstrates how these two methods of DEM processing can affect the simulated water budget. For the example presented, approximately 20% more total flow through the aquifer system is simulated if the centroid value rather than the mean value is used. This is due to the one-third greater average ground water gradients associated with the centroid value than the mean value. The results will vary depending on the particular model area topography and cell size. The use of the mean DEM value in each model cell will result in a more conservative water budget and is more appropriate because the model cell water table value should be representative of the entire cell area, not the centroid of the model cell.

  18. Laminar and turbulent flow in water

    NASA Astrophysics Data System (ADS)

    Riveros, H. G.; Riveros-Rosas, D.

    2010-05-01

    There are many ways to visualize flow, either for laminar or turbulent flows. A very convincing way to show laminar and turbulent flows is by the perturbations on the surface of a beam of water coming out of a cylindrical tube. Photographs, taken with a flash, show the nature of the flow of water in pipes. They clearly show the difference between turbulent and laminar flow, and let, in an accessible way, data be taken to analyse the conditions under which both flows are present. We found research articles about turbulence measurements, using sophisticated equipment, but they do not use the perturbation of the free surface of the flowing liquid to show or measure the turbulence.

  19. Factors affecting sustainability of rural water schemes in Swaziland

    NASA Astrophysics Data System (ADS)

    Peter, Graciana; Nkambule, Sizwe E.

    The Millennium Development Goal (MDG) target to reduce the proportion of people without sustainable access to safe drinking water by the year 2015 has been met as of 2010, but huge disparities exist. Some regions, particularly Sub-Saharan Africa are lagging behind it is also in this region where up to 30% of the rural schemes are not functional at any given time. There is need for more studies on factors affecting sustainability and necessary measures which when implemented will improve the sustainability of rural water schemes. The main objective of this study was to assess the main factors affecting the sustainability of rural water schemes in Swaziland using a Multi-Criteria Analysis Approach. The main factors considered were: financial, social, technical, environmental and institutional. The study was done in Lubombo region. Fifteen functional water schemes in 11 communities were studied. Data was collected using questionnaires, checklist and focused group discussion guide. A total of 174 heads of households were interviewed. Statistical Package for Social Sciences (SPSS) was used to analyse the data and to calculate sustainability scores for water schemes. SPSS was also used to classify sustainability scores according to sustainability categories: sustainable, partially sustainable and non-sustainable. The averages of the ratings for the different sub-factors studied and the results on the sustainability scores for the sustainable, partially sustainable and non-sustainable schemes were then computed and compared to establish the main factors influencing sustainability of the water schemes. The results indicated technical and social factors as most critical while financial and institutional, although important, played a lesser role. Factors which contributed to the sustainability of water schemes were: functionality; design flow; water fetching time; ability to meet additional demand; use by population; equity; participation in decision making on operation and

  20. Water Temperature Affects Susceptibility to Ranavirus.

    PubMed

    Brand, Mabre D; Hill, Rachel D; Brenes, Roberto; Chaney, Jordan C; Wilkes, Rebecca P; Grayfer, Leon; Miller, Debra L; Gray, Matthew J

    2016-06-01

    The occurrence of emerging infectious diseases in wildlife populations is increasing, and changes in environmental conditions have been hypothesized as a potential driver. For example, warmer ambient temperatures might favor pathogens by providing more ideal conditions for propagation or by stressing hosts. Our objective was to determine if water temperature played a role in the pathogenicity of an emerging pathogen (ranavirus) that infects ectothermic vertebrate species. We exposed larvae of four amphibian species to a Frog Virus 3 (FV3)-like ranavirus at two temperatures (10 and 25°C). We found that FV3 copies in tissues and mortality due to ranaviral disease were greater at 25°C than at 10°C for all species. In a second experiment with wood frogs (Lithobates sylvaticus), we found that a 2°C change (10 vs. 12°C) affected ranaviral disease outcomes, with greater infection and mortality at 12°C. There was evidence that 10°C stressed Cope's gray tree frog (Hyla chrysoscelis) larvae, which is a species that breeds during summer-all individuals died at this temperature, but only 10% tested positive for FV3 infection. The greater pathogenicity of FV3 at 25°C might be related to faster viral replication, which in vitro studies have reported previously. Colder temperatures also may decrease systemic infection by reducing blood circulation and the proportion of phagocytes, which are known to disseminate FV3 through the body. Collectively, our results indicate that water temperature during larval development may play a role in the emergence of ranaviruses. PMID:27283058

  1. Environmental water incentive policy and return flows

    NASA Astrophysics Data System (ADS)

    Qureshi, M. E.; Schwabe, K.; Connor, J.; Kirby, M.

    2010-04-01

    With increasing urban, industrial, and agricultural water demand and projected reduced supply under climate change, allocations to the environment are critically low in many arid and semiarid basins. Consequently, many governments are striving to augment environmental flows, often through market-oriented mechanisms that involve compensating irrigated agriculture, the largest water user in most basins, for reducing diversions. A widely documented challenge with policies to recover water for the environment arises because part of the water diversion reduction can form the basis for downstream consumptive water rights or environmental flows. This article gives an empirical comparison of two incentive policies to acquire water for environmental flows for a part of the Murray-Darling Basin (MDB), Australia. One policy consists of paying irrigators and water delivery firms to make capital and management investments that improve on-farm irrigation and water-conveyance; the other policy consists of having the government buy water from irrigators on the active MDB water market. The results show that the first option results in relatively larger return flow reduction, while the second option tends to induce significant irrigated land retirement with relatively large reductions in consumptive use and small reductions in return flow. In cases where irrigation losses result in little useful return flow (e.g., evaporative loss reduction or during drought in some instances), efficiency-improving investments may provide some cost-effective opportunities. Where a large portion of loss forms valuable return flow, it is difficult to make a case for the cost-effectiveness of policies involving payments for investments in irrigation and conveyance system upgrades.

  2. Multimodel Simulation of Water Flow: Uncertainty Analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulations of soil water flow require measurements of soil hydraulic properties which are particularly difficult at the field scale. Laboratory measurements provide hydraulic properties at scales finer than the field scale, whereas pedotransfer functions (PTFs) integrate information on hydraulic pr...

  3. Water tunnel flow visualization using a laser

    NASA Technical Reports Server (NTRS)

    Beckner, C.; Curry, R. E.

    1985-01-01

    Laser systems for flow visualization in water tunnels (similar to the vapor screen technique used in wind tunnels) can provide two-dimensional cross-sectional views of complex flow fields. This parametric study documents the practical application of the laser-enhanced visualization (LEV) technique to water tunnel testing. Aspects of the study include laser power levels, flow seeding (using flourescent dyes and embedded particulates), model preparation, and photographic techniques. The results of this study are discussed to provide potential users with basic information to aid in the design and setup of an LEV system.

  4. How does ice sheet loading affect ocean flow around Antarctica?

    NASA Astrophysics Data System (ADS)

    Dijkstra, H. A.; Rugenstein, M. A.; Stocchi, P.; von der Heydt, A. S.

    2012-12-01

    Interactions and dynamical feedbacks between ocean circulation, heat and atmospheric moisture transport, ice sheet evolution, and Glacial Isostatic Adjustment (GIA) are overlooked issues in paleoclimatology. Here we will present first results on how ocean flows were possibly affected by the glaciation of Antarctica across the Eocene-Oligocene Transition (~ 34 Ma) through GIA and bathymetry variations. GIA-induced gravitationally self-consistent bathymetry variations are determined by solving the Sea Level Equation (SLE), which describes the time dependent shape of (i) the solid Earth and (ii) the equipotential surface of gravity. Since the ocean circulation equations are defined relative to the equipotential surface of gravity, only bathymetry variations can influence ocean flows, although the sea surface slope will also change through time due to gravitational attraction. We use the Hallberg Isopycnal Model under late Eocene conditions to calculate equilibrium ocean flows in a domain in which the bathymetry evolves under ice loading according to the SLE. The bathymetric effects of the glaciation of Antarctica lead to substantial spatial changes in ocean flows, and close to the coast, the flow even reverses direction. Volume transports through the Drake Passage and Tasman Seaway adjust to the new bathymetry. The results indicate that GIA-induced ocean flow variations alone may have had an impact on sedimentation and erosion patterns, the repositioning of fronts, ocean heat transport and grounding line and ice sheet stability.

  5. Development of microcontroller based water flow measurement

    NASA Astrophysics Data System (ADS)

    Munir, Muhammad Miftahul; Surachman, Arif; Fathonah, Indra Wahyudin; Billah, Muhammad Aziz; Khairurrijal, Mahfudz, Hernawan; Rimawan, Ririn; Lestari, Slamet

    2015-04-01

    A digital instrument for measuring water flow was developed using an AT89S52 microcontroller, DS1302 real time clock (RTC), and EEPROM for an external memory. The sensor used for probing the current was a propeller that will rotate if immersed in a water flow. After rotating one rotation, the sensor sends one pulse and the number of pulses are counted for a certain time of counting. The measurement data, i.e. the number of pulses per unit time, are converted into water flow velocity (m/s) through a mathematical formula. The microcontroller counts the pulse sent by the sensor and the number of counted pulses are stored into the EEPROM memory. The time interval for counting is provided by the RTC and can be set by the operator. The instrument was tested under various time intervals ranging from 10 to 40 seconds and several standard propellers owned by Experimental Station for Hydraulic Structure and Geotechnics (BHGK), Research Institute for Water Resources (Pusair). Using the same propellers and water flows, it was shown that water flow velocities obtained from the developed digital instrument and those found by the provided analog one are almost similar.

  6. Can surfactants affect management of non-water repellent soils?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants affect the water relations of water repellent soils but may or may not affect those of wettable soils. We studied the effects of three surfactants, Aquatrols IrrigAid Gold®, an ethylene oxide/propylene oxide block copolymer, and an alkyl polyglycoside, along with untreated tap water as ...

  7. Damping measurements in flowing water

    NASA Astrophysics Data System (ADS)

    Coutu, A.; Seeley, C.; Monette, C.; Nennemann, B.; Marmont, H.

    2012-11-01

    Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

  8. International borders, ground water flow, and hydroschizophrenia.

    PubMed

    Jarvis, Todd; Giordano, Mark; Puri, Shammy; Matsumoto, Kyoko; Wolf, Aaron

    2005-01-01

    A substantial body of research has been conducted on transboundary water, transboundary water law, and the mitigation of transboundary water conflict. However, most of this work has focused primarily on surface water supplies. While it is well understood that aquifers cross international boundaries and that the base flow of international river systems is often derived in part from ground water, transboundary ground water and surface water systems are usually managed under different regimes, resulting in what has been described as "hydroschizophrenia." Adding to the problem, the hydrologic relationships between surface and ground water supplies are only known at a reconnaissance level in even the most studied international basins, and thus even basic questions regarding the territorial sovereignty of ground water resources often remain unaddressed or even unasked. Despite the tensions inherent in the international setting, riparian nations have shown tremendous creativity in approaching regional development, often through preventive diplomacy, and the creation of "baskets of benefits," which allow for positive-sum, integrative allocations of joint gains. In contrast to the notion of imminent water wars, the history of hydropolitical relations worldwide has been overwhelmingly cooperative. Limited ground water management in the international arena, coupled with the fact that few states or countries regulate the use of ground water, begs the question: will international borders serve as boundaries for increased "flows" of hydrologic information and communication to maintain strategic aquifers, or will increased competition for shared ground water resources lead to the potential loss of strategic aquifers and "no flows" for both ground water users? PMID:16149973

  9. Steam-water flow in geothermal wells

    NASA Astrophysics Data System (ADS)

    Shulyupin, A. N.; Chermoshentseva, A. A.

    2015-07-01

    A mathematical model was developed for calculation of steam-water flow in a geothermal well for the feeding interval. The model assumes a variable mass flow rate over the channel length. The basis for this model are the flow continuity equation, momentum and energy conservation equations, taken with account for variable mass flow. The model was implemented as a computer code suitable for calculation of flow parameters upstream (downward the top level of the feeding zone). Then this model was applied for wells in the Mutnovskii geothermal field, this revealed a geyser-type mechanism of flow instabilities with the pressure oscillation period about ten minutes. The remedy for these oscillations was offered.

  10. Nanedi Vallis: Sustained Water FLow?

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This picture of a canyon on the Martian surface was obtained a few minutes after 10 PM PST, January 8, 1998 by the Mars Orbiter Camera (MOC), during the 87th orbit around Mars of the Mars Global Surveyor spacecraft. It shows the canyon of Nanedi Vallis, one of the Martian valley systems cutting through cratered plains in the Xanthe Terra region of Mars. The picture covers an area 9.8 km by 18.5 km (6.1 mi by 11.5 mi), and features as small as 12 m (39 ft) can be seen. The canyon is about 2.5 km (1.6 mi) wide. Rocky outcrops are found along the upper canyon walls; weathered debris is found on the lower canyon slopes and along the canyon floor. The origin of this canyon is enigmatic: some features, such as terraces within the canyon (as seen near the top of the frame) and the small 200 m (660 ft) wide channel (also seen near the top of the frame) suggest continual fluid flow and downcutting. Other features, such as the lack of a contributing pattern of smaller channels on the surface surrounding the canyon, box-headed tributaries, and the size and tightness of the apparent meanders (as seen, for example, in the Viking image 897A32, left), suggest formation by collapse. It is likely that both continual flow and collapse have been responsible for the canyon as it now appears. Further observations, especially in areas west of the present image, will be used to help separate the relative effects of these and other potential formation and modification processes.

    Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  11. Virtual water flows and trade liberalization.

    PubMed

    Ramirez-Vallejo, J; Rogers, P

    2004-01-01

    The linkages between agricultural trade and water resources need to be identified and analyzed to better understand the potential impacts that a full liberalization, or lack thereof, will have on water resources. This paper examines trade of virtual water embodied in agricultural products for most countries of the world. The main purpose of the paper, however, is to examine the impact of trade liberalization on virtual-water trade in the future. Based on a simulation of global agricultural trade, a scenario of full liberalization of agriculture was used to assess the net effect of virtual water flows from the relocation of meat and cereals' trade. The paper also identifies the main reasons behind the changes in the magnitude and direction of the net virtual water trade over time, and shows that virtual water trade flows are independent of water resource endowments, contrary to what the Heckscher-Ohlin Theorem states. Finally, based on a formal model, some input demand functions at the country level are estimated. The estimates of the income and agricultural support elasticities of demand for import of virtual water have the expected sign, and are statistically significant. Variables found to have some explanatory power of the variance of virtual water imports are average income; population; agriculture as value added; irrigated area, and exports of goods and services. PMID:15195413

  12. The Impact of Rhizosphere Processes on Water Flow and Root Water Uptake

    NASA Astrophysics Data System (ADS)

    Schwartz, Nimrod; Kroener, Eva; Carminati, Andrea; Javaux, Mathieu

    2015-04-01

    affect the spatial distribution of root water uptake. This suggests that rhizosphere processes effect root water uptake at the plant scale. Overall, these preliminary results demonstrate the impact of rhizosphere on water flow and root water uptake, and the ability of the Rhizo-RSWMS to simulate these processes. References Javaux, M., Schröder, T., Vanderborght, J., & Vereecken, H. (2008). Use of a three-dimensional detailed modeling approach for predicting root water uptake. Vadose Zone Journal, 7(3), 1079-1088.‏ Kroener, E., Zarebanadkouki, M., Kaestner, A., & Carminati, A. (2014). Nonequilibrium water dynamics in the rhizosphere: How mucilage affects water flow in soils. Water Resources Research, 50(8), 6479-6495.‏

  13. Metals in Particulate Pollutants Affect Peak Expiratory Flow of Schoolchildren

    PubMed Central

    Hong, Yun-Chul; Hwang, Seung-Sik; Kim, Jin Hee; Lee, Kyoung-Ho; Lee, Hyun-Jung; Lee, Kwan-Hee; Yu, Seung-Do; Kim, Dae-Seon

    2007-01-01

    Background The contribution of the metal components of particulate pollutants to acute respiratory effects has not been adequately evaluated. Moreover, little is known about the effects of genetic polymorphisms of xenobiotic metabolism on pulmonary function. Objectives This study was conducted to assess lung function decrement associated with metal components in particulate pollutants and genetic polymorphisms of glutathione S-transferase M1 and T1. Methods We studied 43 schoolchildren who were in the 3rd to 6th grades. Each student measured peak expiratory flow rate three times a day for 42 days. Particulate air concentrations were monitored every day, and the concentrations of iron, manganese, lead, zinc, and aluminum in the particles were measured. Glutathione S-transferase M1 and T1 genetic polymorphisms were determined using DNA extracted from participant buccal washings. We used a mixed linear regression model to estimate the association between peak expiratory flow rate and particulate air pollutants. Results We found significant reduction in the peak expiratory flow rate after the children’s exposure to particulate pollutants. The effect was shown most significantly 1 day after exposure to the ambient particles. Manganese and lead in the particles also reduced the peak expiratory flow rate. Genetic polymorphisms of glutathione S-transferase M1 and T1 did not significantly affect peak expiratory flow rate. Conclusions This study demonstrated that particulate pollutants and metals such as manganese and lead in the particles are associated with a decrement of peak expiratory flow rate. These effects were robust even with consideration of genetic polymorphisms of glutathione S-transferase. PMID:17431494

  14. Models for water steam condensing flows

    NASA Astrophysics Data System (ADS)

    Wróblewski, Włodzimierz; Dykas, Sławomir; Chmielniak, Tadeusz

    2012-08-01

    The paper presents a description of selected models dedicated to steam condensing flow modelling. The models are implemented into an in-house computational fluid dynamics code that has been successfully applied to wet steam flow calculation for many years now. All models use the same condensation model that has been validated against the majority of available experimental data. The state equations for vapour and liquid water, the physical model as well as the numerical techniques of solution to flow governing equations have been presented. For the single-fluid model, the Reynolds-averaged Navier-Stokes equations for vapour/liquid mixture are solved, whereas the two-fluid model solves separate flow governing equations for the compressible, viscous and turbulent vapour phase and for the compressible and inviscid liquid phase. All described models have been compared with relation to the flow through the Laval nozzle.

  15. Non-classical shallow water flows

    NASA Astrophysics Data System (ADS)

    Edwards, Carina M.; Howison, S. D.; Ockendon, H.; Ockendon, J. R.

    2008-02-01

    This paper deals with violent discontinuities in shallow water flows with large Froude number F. On a horizontal base, the paradigm problem is that of the impact of two fluid layers in situations where the flow can be modelled as two smooth regions joined by a singularity in the flow field. Within the framework of shallow water theory, we show that, over a certain time-scale, this discontinuity may be described by a delta shock, which is a weak solution of the underlying conservation laws in which the depth and mass and momentum fluxes have both delta function and step function components. We also make some conjectures about how this model evolves from the traditional model for jet impacts in which a spout is emitted. For flows on a sloping base, we show that for flow with an aspect ratio of O(F-2) on a base with an O(1) or larger slope, the governing equations admit a new type of discontinuous solution that is also modelled as a delta shock. The physical manifestation of this discontinuity is a small tube' of fluid bounding the flow. The delta-shock conditions for this flow are derived and solved for a point source on an inclined plane. This latter delta-shock framework also sheds light on the evolution of the layer impact on a horizontal base

  16. Influence of water flow on pipe inspection

    NASA Astrophysics Data System (ADS)

    Ahmad, Rais; Banerjee, Sourav; Kundu, Tribikram

    2005-05-01

    From various studies by different investigators it has been now well established that a number of cylindrical guided wave modes are sensitive to the pipe wall defects. Several investigations by these authors and other researchers showed that the strengths of the guided waves propagating through a pipe that is placed in air are reduced when the pipe wall defects are encountered. This reduction is expected because the pipe wall defects (gouge, dent, removed metal due to corrosion etc.) alter the pipe geometry, hampering the free propagation of guided wave modes. When water flows through the pipes, the guided wave technique becomes more challenging because the flowing water absorbs part of the propagating acoustic energy. Flowing water may also induce some standing modes. The propagating cylindrical guided wave modes become leaky modes in presence of the flowing water, in other words energy leaks into water. Therefore, the energy detected by a receiver, placed at a large distance from the transmitter, is reduced even for a defect free pipe. Further reduction in the signal strength occurs in presence of defects.

  17. Water-in-Water Droplets by Passive Microfluidic Flow Focusing.

    PubMed

    Moon, Byeong-Ui; Abbasi, Niki; Jones, Steven G; Hwang, Dae Kun; Tsai, Scott S H

    2016-04-01

    We present a simple microfluidic system that generates water-in-water, aqueous two phase system (ATPS) droplets, by passive flow focusing. ATPS droplet formation is achieved by applying weak hydrostatic pressures, with liquid-filled pipette tips as fluid columns at the inlets, to introduce low speed flows to the flow focusing junction. To control the size of the droplets, we systematically vary the interfacial tension and viscosity of the ATPS fluids and adjust the fluid column height at the fluid inlets. The size of the droplets scales with a power law of the ratio of viscous stresses in the two ATPS phases. Overall, we find a drop size coefficient of variation (CV; i.e., polydispersity) of about 10%. We also find that when drops form very close to the flow focusing junction, the drops have a CV of less than 1%. Our droplet generation method is easily scalable: we demonstrate a parallel system that generates droplets simultaneously and improves the droplet production rate by up to one order of magnitude. Finally, we show the potential application of our system for encapsulating cells in water-in-water emulsions by encapsulating microparticles and cells. To the best of our knowledge, our microfluidic technique is the first that forms low interfacial tension ATPS droplets without applying external perturbations. We anticipate that this simple approach will find utility in drug and cell delivery applications because of the all-biocompatible nature of the water-in-water ATPS environment. PMID:26959358

  18. Flow properties of coal-water mixtures

    SciTech Connect

    Ekmann, J.M.; Wildman, D.J.

    1983-01-01

    A study of the flow properties of highly loaded suspensions has been in progress at the Pittsburgh Energy Technology Center (PETC) since mid-1981. Preliminary results of this test program were reported at the Fourth Symposium. This paper presents results from the continuation of this effort; the research to date has focused on coal-water mixtures prepared at PETC without the use of special particle size distributions. The program is conducted using a flow loop facility and a supporting laboratory. The results of the tests to date indicate that the coarser suspensions behave as shear-thinning fluids and exhibit lower pressure losses through the range of concentrations tested. For the coarse material, the range of concentrations and velocities studied includes regions of homogeneous and nonhomogeneous flow. For all particle size distributions studied, the data for the steady, homogeneous flow conditions can be fit with simple models for the laminar flow of time-independent fluids. For nonsteady flows (e.g., elbows), some evidence of secondary flows exists at low concentrations. Furthermore, the measured differences between vertical-to-horizontal and horizontal-to-vertical transitions require additional study. The nonhomogeneous flow conditions are not amenable to a simple modeling approach. More complex expressions that adequately include the effect of the high solids concentrations on settling velocities will be utilized. 9 figures.

  19. A water-budget approach to restoring a sedge fen affected by diking and ditching

    USGS Publications Warehouse

    Wilcox, Douglas A.; Sweat, Michael J.; Carlson, Martha L.; Kowalski, Kurt P.

    2006-01-01

    A vast, ground-water-supported sedge fen in the Upper Peninsula of Michigan, USA was ditched in the early 1900s in a failed attempt to promote agriculture. Dikes were later constructed to impound seasonal sheet surface flows for waterfowl management. The US Fish and Wildlife Service, which now manages the wetland as part of Seney National Wildlife Refuge, sought to redirect water flows from impounded C-3 Pool to reduce erosion in downstream Walsh Ditch, reduce ground-water losses into the ditch, and restore sheet flows of surface water to the peatland. A water budget was developed for C-3 Pool, which serves as the central receiving and distribution body for water in the affected wetland. Surface-water inflows and outflows were measured in associated ditches and natural creeks, ground-water flows were estimated using a network of wells and piezometers, and precipitation and evaporation/evapotranspiration components were estimated using local meteorological data. Water budgets for the 1999 springtime peak flow period and the 1999 water year were used to estimate required releases of water from C-3 Pool via outlets other than Walsh Ditch and to guide other restoration activities. Refuge managers subsequently used these results to guide restoration efforts, including construction of earthen dams in Walsh Ditch upslope from the pool to stop surface flow, installation of new water-control structures to redirect surface water to sheet flow and natural creek channels, planning seasonal releases from C-3 Pool to avoid erosion in natural channels, stopping flow in downslope Walsh Ditch to reduce erosion, and using constructed earthen dams and natural beaver dams to flood the ditch channel below C-3 Pool. Interactions between ground water and surface water are critical for maintaining ecosystem processes in many wetlands, and management actions directed at restoring either ground- or surface-water flow patterns often affect both of these components of the water budget. This

  20. A water-budget approach to restoring a sedge fen affected by diking and ditching

    NASA Astrophysics Data System (ADS)

    Wilcox, Douglas A.; Sweat, Michael J.; Carlson, Martha L.; Kowalski, Kurt P.

    2006-04-01

    A vast, ground-water-supported sedge fen in the Upper Peninsula of Michigan, USA was ditched in the early 1900 s in a failed attempt to promote agriculture. Dikes were later constructed to impound seasonal sheet surface flows for waterfowl management. The US Fish and Wildlife Service, which now manages the wetland as part of Seney National Wildlife Refuge, sought to redirect water flows from impounded C-3 Pool to reduce erosion in downstream Walsh Ditch, reduce ground-water losses into the ditch, and restore sheet flows of surface water to the peatland. A water budget was developed for C-3 Pool, which serves as the central receiving and distribution body for water in the affected wetland. Surface-water inflows and outflows were measured in associated ditches and natural creeks, ground-water flows were estimated using a network of wells and piezometers, and precipitation and evaporation/evapotranspiration components were estimated using local meteorological data. Water budgets for the 1999 springtime peak flow period and the 1999 water year were used to estimate required releases of water from C-3 Pool via outlets other than Walsh Ditch and to guide other restoration activities. Refuge managers subsequently used these results to guide restoration efforts, including construction of earthen dams in Walsh Ditch upslope from the pool to stop surface flow, installation of new water-control structures to redirect surface water to sheet flow and natural creek channels, planning seasonal releases from C-3 Pool to avoid erosion in natural channels, stopping flow in downslope Walsh Ditch to reduce erosion, and using constructed earthen dams and natural beaver dams to flood the ditch channel below C-3 Pool. Interactions between ground water and surface water are critical for maintaining ecosystem processes in many wetlands, and management actions directed at restoring either ground- or surface-water flow patterns often affect both of these components of the water budget. This

  1. Does topical phenylephrine, tropicamide, or proparacaine affect macular blood flow?

    PubMed

    Robinson, F; Petrig, B L; Sinclair, S H; Riva, C E; Grunwald, J E

    1985-08-01

    The acute effect of topical phenylephrine HCl 10%, tropicamide 1% and proparacaine HCl 0.5% on macular capillary blood flow was studied in six healthy human volunteers using the blue field simulation technique. This technique provides a method for quantifying the velocity of leukocytes flowing in one's own retinal macular capillaries. Patients adjusted the velocity of computer simulated leukocytes moving on a CRT screen to match that of their own entoptically perceived leukocytes before instillation of each of the tested preparations and for 35 minutes immediately thereafter A 5% NaCl solution was used as a control. We found no significant difference in leukocyte velocity between the control drop and any of the tested drugs. With the six subjects tested, the calculated average minimum percentage change in leukocyte velocity detectable with this technique (P less than 0.05, paired t-test) was 9%. None of the tested drugs affected macular leukocyte velocity, and presumably blood flow, by more than this amount. PMID:4047607

  2. Unstable Pore-Water Flow in Intertidal Wetlands

    NASA Astrophysics Data System (ADS)

    Barry, D. A.; Shen, C.; Li, L.

    2014-12-01

    Salt marshes are important intertidal wetlands strongly influenced by interactions between surface water and groundwater. Bordered by coastal water, the marsh system undergoes cycles of inundation and exposure driven by the tide. This leads to dynamic, complex pore-water flow and solute transport in the marsh soil. Pore-water circulations occur over vastly different spatial and temporal scales with strong link to the marsh topography. These circulations control solute transport between the marsh soil and the tidal creek, and ultimately affect the overall nutrient exchange between the marsh and coastal water. The pore-water flows also dictate the soil condition, particularly aeration, which influences the marsh plant growth. Numerous studies have been carried out to examine the pore-water flow process in the marsh soil driven by tides, focusing on stable flow with the assumption of homogeneity in soil and fluid properties. This assumption, however, is questionable given the actual inhomogeneous conditions in the field. For example, the salinity of surface water in the tidal creek varies temporally and spatially due to the influence of rainfall and evapotranspiration as well as the freshwater input from upland areas to the estuary, creating density gradients across the marsh surface and within the marsh soil. Many marshes possess soil stratigraphy with low-permeability mud typically overlying high-permeability sandy deposits. Macropores such as crab burrows are commonly distributed in salt marsh sediments. All these conditions are prone to the development of non-uniform, unstable preferential pore-water flow in the marsh soil, for example, funnelling and fingering. Here we present results from laboratory experiments and numerical simulations to explore such unstable flow. In particular, the analysis aims to address how the unstable flow modifies patterns of local pore-water movement and solute transport, as well as the overall exchange between the marsh soil and

  3. The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review

    NASA Astrophysics Data System (ADS)

    Lei, Wenwen; Rigozzi, Michelle K.; McKenzie, David R.

    2016-02-01

    This review assesses the current state of understanding of the calculation of the rate of flow of gases, vapours and liquids confined in channels, in porous media and in permeable materials with an emphasis on the flow of water and its vapour. One motivation is to investigate the relation between the permeation rate of moisture and that of a noncondensable test gas such as helium, another is to assist in unifying theory and experiment across disparate fields. Available theories of single component ideal gas flows in channels of defined geometry (cylindrical, rectangular and elliptical) are described and their predictions compared with measurement over a wide range of conditions defined by the Knudsen number. Theory for two phase flows is assembled in order to understand the behaviour of four standard water leak configurations: vapour, slug, Washburn and liquid flow, distinguished by the number and location of phase boundaries (menisci). Air may or may not be present as a background gas. Slip length is an important parameter that greatly affects leak rates. Measurements of water vapour flows confirm that water vapour shows ideal gas behaviour. Results on carbon nanotubes show that smooth walls may lead to anomalously high slip lengths arising from the properties of ‘confined’ water. In porous media, behaviour can be matched to the four standard leaks. Traditional membrane permeation models consider that the permeant dissolves, diffuses and evaporates at the outlet side, ideas we align with those from channel flow. Recent results on graphite oxide membranes show examples where helium which does not permeate while at the same time moisture is almost unimpeded, again a result of confined water. We conclude that while there is no a priori relation between a noncondensable gas flow and a moisture flow, measurements using helium will give results within two orders of magnitude of the moisture flow rate, except in the case where there is anomalous slip or confined

  4. The physics of confined flow and its application to water leaks, water permeation and water nanoflows: a review.

    PubMed

    Lei, Wenwen; Rigozzi, Michelle K; McKenzie, David R

    2016-02-01

    This review assesses the current state of understanding of the calculation of the rate of flow of gases, vapours and liquids confined in channels, in porous media and in permeable materials with an emphasis on the flow of water and its vapour. One motivation is to investigate the relation between the permeation rate of moisture and that of a noncondensable test gas such as helium, another is to assist in unifying theory and experiment across disparate fields. Available theories of single component ideal gas flows in channels of defined geometry (cylindrical, rectangular and elliptical) are described and their predictions compared with measurement over a wide range of conditions defined by the Knudsen number. Theory for two phase flows is assembled in order to understand the behaviour of four standard water leak configurations: vapour, slug, Washburn and liquid flow, distinguished by the number and location of phase boundaries (menisci). Air may or may not be present as a background gas. Slip length is an important parameter that greatly affects leak rates. Measurements of water vapour flows confirm that water vapour shows ideal gas behaviour. Results on carbon nanotubes show that smooth walls may lead to anomalously high slip lengths arising from the properties of 'confined' water. In porous media, behaviour can be matched to the four standard leaks. Traditional membrane permeation models consider that the permeant dissolves, diffuses and evaporates at the outlet side, ideas we align with those from channel flow. Recent results on graphite oxide membranes show examples where helium which does not permeate while at the same time moisture is almost unimpeded, again a result of confined water. We conclude that while there is no a priori relation between a noncondensable gas flow and a moisture flow, measurements using helium will give results within two orders of magnitude of the moisture flow rate, except in the case where there is anomalous slip or confined water

  5. WATER QUALITY CHANGES IN HYPORHEIC FLOW AT THE AQUATIC-TERRESTRIAL INTERFACE OF A LARGER RIVER

    EPA Science Inventory

    Exchange between river water and groundwater in hyporheic flow at the aquatic-terrestrial interface can importantly affect water quality and aquatic habitat in the main channel of large rivers and at off-channel sites that include flowing and stagnant side channels. With tracer ...

  6. Arsenic in drinking water in bangladesh: factors affecting child health.

    PubMed

    Aziz, Sonia N; Aziz, Khwaja M S; Boyle, Kevin J

    2014-01-01

    The focus of this paper is to present an empirical model of factors affecting child health by observing actions households take to avoid exposure to arsenic in drinking water. Millions of Bangladeshis face multiple health hazards from high levels of arsenic in drinking water. Safe water sources are either expensive or difficult to access, affecting people's individuals' time available for work and ultimately affecting the health of household members. Since children are particularly susceptible and live with parents who are primary decision makers for sustenance, parental actions linking child health outcomes is used in the empirical model. Empirical results suggest that child health is significantly affected by the age and gender of the household water procurer. Adults with a high degree of concern for children's health risk from arsenic contamination, and who actively mitigate their arsenic contaminated water have a positive effect on child health. PMID:24982854

  7. Arsenic in Drinking Water in Bangladesh: Factors Affecting Child Health

    PubMed Central

    Aziz, Sonia N.; Aziz, Khwaja M. S.; Boyle, Kevin J.

    2014-01-01

    The focus of this paper is to present an empirical model of factors affecting child health by observing actions households take to avoid exposure to arsenic in drinking water. Millions of Bangladeshis face multiple health hazards from high levels of arsenic in drinking water. Safe water sources are either expensive or difficult to access, affecting people’s individuals’ time available for work and ultimately affecting the health of household members. Since children are particularly susceptible and live with parents who are primary decision makers for sustenance, parental actions linking child health outcomes is used in the empirical model. Empirical results suggest that child health is significantly affected by the age and gender of the household water procurer. Adults with a high degree of concern for children’s health risk from arsenic contamination, and who actively mitigate their arsenic contaminated water have a positive effect on child health. PMID:24982854

  8. The role of fault zone in affecting multiphase flow at Yucca Mountain

    SciTech Connect

    Tsang, Y.W.; Pruess, K.; Wang, J.S.Y.

    1993-12-31

    Within Yucca Mountain, the potential High Level Nuclear-Waste Repository site, there are large scale fault zones, most notably the Ghost Dance Fault. The effect of such high-permeability, large-scale discontinuities on the flow and transport is a question of concern in assessing the ability of the site to isolate radio-nuclides from the biosphere. In this paper, we present a numerical study to investigate the role of the fault in affecting both the liquid and gas phase flows in the natural state at Yucca Mountain prior to waste emplacement, as well as after the waste emplacement when the fluid flow is strongly heat-driven. Our study shows that if the characteristic curves of the Ghost Dance Fault obey the same relationship between saturated permeability and capillary scaling parameter, is as observed from the measured data of Yucca Mountain welded and nonwelded tuffs, Apache Leap tuffs, and Las Cruces soil, then a large saturated permeability of the Ghost Dance Fault will play little role in channeling water into the fault, or in enhancing the flow of water down the fault. However, the Fault may greatly enhance the upward gas flow after emplacement of waste. This may have implications on the transport of gaseous radio-nuclides such as C{sup 14}. The results of this study also focus attention on the need for field measurements of fluid flow in the fault zones.

  9. The role of fault zones in affecting multiphase flow at Yucca Mountain

    SciTech Connect

    Tsang, Y.W.; Pruess, K.; Wang, J.S.Y.

    1993-01-01

    Within Yucca Mountain, the potential High Level Nuclear-Waste Repository site, there are large scale fault zones, most notably the Ghost Dance Fault. The effect of such high-permeability, large scale discontinuities on the flow and transport is a question of concern in assessing the ability of the site to isolate radio-nuclides from the biosphere. In this paper, we present a numerical study to investigate the role of the fault in affecting both the liquid and gas phase flows in the natural state at Yucca Mountain prior to waste emplacement, as well as after the waste emplacement when the fluid flow is strongly heat-driven. Our study shows that if the characteristic curves of the Ghost Dance Fault obey the same relationship between saturated permeability and capillary scaling parameter, as is observed from the measured data of Yucca Mountain welded and nonwelded tuffs. Apache Leap tuffs, and Las Cruces soil, then a large saturated permeability of the Ghost Dance Fault will play little role in channeling water into the fault, or inenhancing the flow of water down the fault. However, the Fault may greatly enhance the upward gas flow after emplacement of waste. This may have implications on the transport of gaseous radio-nuclides such as C{sup 14}. The results of this study also focus attention on the need for field measurements of fluid flow in the fault zones.

  10. Water flow in poly(N-isopropylacrylamide) gels

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsushi; Yoshikawa, Muneyuki

    2006-11-01

    Friction between a polymer network of poly(N-isopropylacrylamide) gels and solvent water was investigated. The gel was mechanically constrained in a glass capillary at gelation, and hydrostatic pressure was directly applied to the cross section of the cylinder. The temperature dependence of the flow velocity was extensively measured in the vicinity of the transition temperature for gels with different lengths, l0, at gelation. As the temperature increased, the friction slightly decreased at the transition point and increased rapidly in the collapsed phase. Although the flow velocity depended on l0, the friction in the vicinity of the transition point was well scaled by l0 based on the Hagen-Poiseuille equation for the flux of water flow in a capillary. The results suggested that the assumption that the gel is a bundle of microcapillaries was applicable to the water flow through the hydrogel, which was largely deformed not only by the pressure applied to the solvent but also by the shrinking force caused by the temperature increment. Macroscopic deformation did not affect the friction between the three-dimensional polymer network and water.

  11. A coupled heat and water flow apparatus

    SciTech Connect

    Mohamed, A.M.O.; Caporouscio, F.; Yong, R.N. ); Cheung, C.H. ); Kjartanson, B.H. )

    1993-03-01

    Safe and permanent disposal of radioactive waste requires isolation of a number of diverse chemical elements form the environment. The Canadian Nuclear Fuel Waste Management Program is assessing the concept of disposing of waste in a vault excavated at a depth of 500 to 1000 m below the ground surface in plutonic rock of the Canadian Shield. The temperatures and hydraulic potential in the buffer and back fill material were investigated. To study the performance of a compacted buffer material under thermal and isothermal conditions, a coupled heat and water flow apparatus is designed and presented. In the preliminary design, a one-dimensional flow of heat and water was not achieved. however, control of temperature gradient, existence of one-dimensional flow, and uniformity of temperature and volumetric water content distributions at any cross section within the specimen are achieved in the modified design. Experimental results have shown that the temperature stabilizes very rapidly after a period of approximately 0. 107 days. The moisture moves away from the hot end along the longitudinal direction of the specimen due to imposed thermal gradient. The time required for moisture to stabilize is in order of days. 17 refs., 17 figs., 3 tabs.

  12. Simulation of ground-water flow and areas contributing ground water to production wells, Cadillac, Michigan

    USGS Publications Warehouse

    Hoard, Christopher J.; Westjohn, David B.

    2005-01-01

    Ground water is the primary source of water for domestic, municipal, and industrial use within the northwest section of Michigan's Lower Peninsula. Because of the importance of this resource, numerous communities including the city of Cadillac in Wexford County, Michigan, have begun local wellhead protection programs. In these programs, communities protect their ground-water resources by identifying the areas that contribute water to production wells, identifying potential sources of contamination, and developing methods to cooperatively manage and minimize threats to the water supply. The U.S. Geological Survey, in cooperation with the city of Cadillac, simulated regional ground-water flow and estimated areas contributing recharge and zones of transport to the production well field. Ground-water flow models for the Clam River watershed, in Wexford and Missaukee Counties, were developed using the U.S. Geological Survey modular three-dimensional finite-difference ground-water flow model (MODFLOW 2000). Ground-water flow models were calibrated using the observation, sensitivity, and parameter estimation packages of MODFLOW 2000. Ground-water-head solutions from calibrated flow models were used in conjunction with MODPATH, a particle-tracking program, to simulate regional ground-water flow and estimate areas contributing recharge and zones of transport to the Cadillac production-well field for a 10-year period. Model simulations match the conceptual model in that regional ground-water flow in the deep ground-water system is from southeast to northwest across the watershed. Areas contributing water were determined for the optimized parameter set and an alternate parameter set that included increased recharge and hydraulic conductivity values. Although substantially different hydrologic parameters (assumed to represent end-member ranges of realistic hydrologic parameters) were used in alternate numerical simulations, simulation results differ little in predictions of

  13. Does Water Content or Flow Rate Control Colloid Transport in Unsaturated Porous Media?

    SciTech Connect

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

    2014-03-01

    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 = (? – ?r)/(?s – ?r)) 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 < 0.1), 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.

  14. Water Bouncing Balls: how material stiffness affects water entry

    NASA Astrophysics Data System (ADS)

    Truscott, Tadd

    2014-03-01

    It is well known that one can skip a stone across the water surface, but less well known that a ball can also be skipped on water. Even though 17th century ship gunners were aware that cannonballs could be skipped on the water surface, they did not know that using elastic spheres rather than rigid ones could greatly improve skipping performance (yet would have made for more peaceful volleys). The water bouncing ball (Waboba®) is an elastic ball used in a game of aquatic keep away in which players pass the ball by skipping it along the water surface. The ball skips easily along the surface creating a sense that breaking the world record for number of skips could easily be achieved (51 rock skips Russell Byers 2007). We investigate the physics of skipping elastic balls to elucidate the mechanisms by which they bounce off of the water. High-speed video reveals that, upon impact with the water, the balls create a cavity and deform significantly due to the extreme elasticity; the flattened spheres resemble skipping stones. With an increased wetted surface area, a large hydrodynamic lift force is generated causing the ball to launch back into the air. Unlike stone skipping, the elasticity of the ball plays an important roll in determining the success of the skip. Through experimentation, we demonstrate that the deformation timescale during impact must be longer than the collision time in order to achieve a successful skip. Further, several material deformation modes can be excited upon free surface impact. The effect of impact velocity and angle on the two governing timescales and material wave modes are also experimentally investigated. Scaling for the deformation and collision times are derived and used to establish criteria for skipping in terms of relevant physical parameters.

  15. The effect of water temperature and synoptic winds on the development of surface flows over narrow, elongated water bodies

    NASA Technical Reports Server (NTRS)

    Segal, M.; Pielke, R. A.

    1985-01-01

    Simulations of the thermally induced breeze involved with a relatively narrow, elongated water body is presented in conjunction with evaluations of sensible heat fluxes in a stable marine atmospheric surface layer. The effect of the water surface temperature and of the large-scale synoptic winds on the development of surface flows over the water is examined. As implied by the sensible heat flux patterns, the simulation results reveal the following trends: (1) when the synoptic flow is absent or light, the induced surface breeze is not affected noticeably by a reduction of the water surface temperature; and (2) for stronger synoptic flow, the resultant surface flow may be significantly affected by the water surface temperature.

  16. Instability of a water-spout flow

    NASA Astrophysics Data System (ADS)

    Carrión, Luis; Herrada, Miguel A.; Shtern, Vladimir N.

    2016-03-01

    The paper studies the linear stability of a steady axisymmetric air-water motion in a vertical sealed cylinder, driven by the rotating top disk, motivated by possible applications in aerial bioreactors. As the flow strength Re increases, a vortex breakdown bubble (VBB) emerges near the bottom center and expands toward the interface. Regions of clockwise meridional circulation of air and water become separated by a thin anticlockwise circulation layer (TCL) adjacent to the interface in water. This study reveals that instability develops for larger Re than those at which VBB and TCL emerge. The instability focuses in the air region being typically of shear-layer type. The instability is centrifugal if the air volume fraction is small.

  17. How to Model Water Flow in Moulins?

    NASA Astrophysics Data System (ADS)

    Phillips, T. P.; Steffen, K.

    2007-12-01

    The development of large melt ponds on the Greenland Ice Sheet (GIS) and their drainage system indicate that moulins are a major contributor to the englacial water system. Here we review the current state of knowledge and the history of moulin research. In the late 19th century glaciologists led by Vallot climbed and studied the Grand Moulin on Mont Blanc. Despite being considered mystic due to their size and water drainage they have been studied by a few scientists such as Holmlund and Hooke (1980) or Puccini and Badino (1990). We develop a qualitative model of geometry as well as of the driving forces in the life cycle of moulins using data, photos, sketches, and climbing reports by ice speleologists and climbers. The GIS is temperate for the first 10 km at its margin and consists of cold ice further inland. The recent increase in melt water leads to an increase in basal water availability. The observed increase in ice velocity might be caused by the lubrication at the bed combined with a possible temperature rise in the cold part of the GIS. The raise of englacial water flow increases the volume of the conduits thus reducing the timing of water to reach the ice sheet bed. Our initial model starts with a narrow englacial non-arborescent channel network. We anticipate the development of the englacial hydrology system by using the 'Roethlisberger' conduit model. In addition we will show first model results on temperature fluctuations in the ice due to the hydrologic system.

  18. Removing the impact of water abstractions on flow duration curves

    NASA Astrophysics Data System (ADS)

    Masoero, Alessandro; Ganora, Daniele; Galeati, Giorgio; Laio, Francesco; Claps, Pierluigi

    2015-04-01

    Changes and interactions between human system and water cycle are getting increased attention in the scientific community. Commonly discharge data needed for water resources studies were collected close to urban or industrial settlements, thus in environments where the interest for surveying was not merely scientific, but also for socio-economical purposes. Working in non-natural environments we must take into account human impacts, like the one due to water intakes for irrigation or hydropower generation, while assessing the actual water availability and variability in a river. This can became an issue in alpine areas, where hydropower exploitation is heavy and it is common to have water abstraction before a gauge station. To have a gauge station downstream a water intake can be useful to survey the environmental flow release and to record the maximum flood values, which should not be affected by the water abstraction. Nevertheless with this configuration we are unable to define properly the water volumes available in the river, information crucial to assess low flows and investigate drought risk. This situation leads to a substantial difference between observed data (affected by the human impact) and natural data (as would have been without abstraction). A main issue is how to correct these impacts and restore the natural streamflow values. The most obvious and reliable solution would be to ask for abstraction data to water users, but these data are hard to collect. Usually they are not available, because not public or not even collected by the water exploiters. A solution could be to develop a rainfall-run-off model of the basin upstream the gauge station, but this approach needs a great number of data and parameters Working in a regional framework and not on single case studies, our goal is to provide a consistent estimate of the non-impacted statistics of the river (i.e. mean value, L-moments of variation and skewness). We proposed a parsimonious method, based

  19. 49 CFR 229.111 - Water-flow indicator.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Water-flow indicator. 229.111 Section 229.111....111 Water-flow indicator. (a) Steam generators shall be equipped with an illuminated visual return water-flow indicator. (b) Steam generators shall be equipped with an operable test valve or other...

  20. 49 CFR 229.111 - Water-flow indicator.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Water-flow indicator. 229.111 Section 229.111....111 Water-flow indicator. (a) Steam generators shall be equipped with an illuminated visual return water-flow indicator. (b) Steam generators shall be equipped with an operable test valve or other...

  1. 49 CFR 229.111 - Water-flow indicator.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Water-flow indicator. 229.111 Section 229.111....111 Water-flow indicator. (a) Steam generators shall be equipped with an illuminated visual return water-flow indicator. (b) Steam generators shall be equipped with an operable test valve or other...

  2. 49 CFR 229.111 - Water-flow indicator.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Water-flow indicator. 229.111 Section 229.111....111 Water-flow indicator. (a) Steam generators shall be equipped with an illuminated visual return water-flow indicator. (b) Steam generators shall be equipped with an operable test valve or other...

  3. Base flow and ground water in upper Sweetwater Valley, Tennessee

    USGS Publications Warehouse

    Evaldi, R.D.; Lewis, J.G.

    1983-01-01

    Base flow measurements showed interbasin transfer of water among sub-basins of upper Sweetwater Valley. In general, topographically higher sub-basins have deficient surface outflow unless significant spring flow occurs in the basin. Topographically lower areas adjacent to the main channel of Sweetwater Creek generally have surplus flow. Major flow surpluses were associated with areas in which the majority of flow originated at a spring. Unusual outflow was related to geology to hypothesize a ground-water flow network. Areas of ground-water flow up-gradient of large springs were hypothesized as likely areas for significant ground-water reservoirs. A water budget study indicated that during dry years approximately three-fourths of the annual flow to Sweetwater Creek may be derived from ground-water sources. Streamflow records were analyzed to estimate the frequency of low-flow of Sweetwater Creek. (USGS)

  4. How does tidal flow affect pattern formation in mussel beds?

    PubMed

    Sherratt, Jonathan A; Mackenzie, Julia J

    2016-10-01

    In the Wadden Sea, mussel beds self-organise into spatial patterns consisting of bands parallel to the shore. A leading explanation for this phenomenon is that mussel aggregation reduces losses from dislodgement and predation, because of the adherence of mussels to one another. Previous mathematical modelling has shown that this can lead to spatial patterning when it is coupled to the advection from the open sea of algae-the main food source for mussels in the Wadden Sea. A complicating factor in this process is that the advection of algae will actually oscillate with the tidal flow. This has been excluded from previous modelling studies, and the present paper concerns the implications of this oscillation for pattern formation. The authors initially consider piecewise constant ("square-tooth") oscillations in advection, which enables analytical investigation of the conditions for pattern formation. They then build on this to study the more realistic case of sinusoidal oscillations. Their analysis shows that future research on the details of pattern formation in mussel beds will require an in-depth understanding of how the tides affect long-range inhibition among mussels. PMID:27343625

  5. Nutrient transport as affected by rate of overland flow

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little information is currently available concerning the effects of varying flow rate on nutrient transport by overland flow. The objective of this study was to measure the effects of overland flow rate on nutrient transport following the application of beef cattle or swine manure to plots containin...

  6. A seepage meter designed for use in flowing water

    USGS Publications Warehouse

    Rosenberry, D.O.

    2008-01-01

    Seepage meters provide one of the most direct means to measure exchange of water across the sediment-water interface, but they generally have been unsuitable for use in fluvial settings. Although the seepage bag can be placed inside a rigid container to minimize velocity head concerns, the seepage cylinder installed in the sediment bed projects into and disrupts the flow field, altering both the local-scale fluid exchange as well as measurement of that exchange. A low-profile seepage meter designed for use in moving water was tested in a seepage meter flux tank where both current velocity and seepage velocity could be controlled. The conical seepage cylinder protrudes only slightly above the sediment bed and is connected via tubing to a seepage bag or flowmeter positioned inside a rigid shelter that is located nearby where current velocity is much slower. Laboratory and field tests indicate that the net effect of the small protrusion of the seepage cylinder into the surface water flow field is inconsequentially small for surface water currents up to 65 cm s-1. Current velocity affects the variability of seepage measurements; seepage standard deviation increased from ???2 to ???6 cm d-1 as current velocity increased from 9 to 65 cm s-1. Substantial bias can result if the shelter is not placed to minimize hydraulic gradient between the bag and the seepage cylinder.

  7. Flow Analysis on a Limited Volume Chilled Water System

    SciTech Connect

    Zheng, Lin

    2012-07-31

    LANL Currently has a limited volume chilled water system for use in a glove box, but the system needs to be updated. Before we start building our new system, a flow analysis is needed to ensure that there are no high flow rates, extreme pressures, or any other hazards involved in the system. In this project the piping system is extremely important to us because it directly affects the overall design of the entire system. The primary components necessary for the chilled water piping system are shown in the design. They include the pipes themselves (perhaps of more than one diameter), the various fitting used to connect the individual pipes to form the desired system, the flow rate control devices (valves), and the pumps that add energy to the fluid. Even the most simple pipe systems are actually quite complex when they are viewed in terms of rigorous analytical considerations. I used an 'exact' analysis and dimensional analysis considerations combined with experimental results for this project. When 'real-world' effects are important (such as viscous effects in pipe flows), it is often difficult or impossible to use only theoretical methods to obtain the desired results. A judicious combination of experimental data with theoretical considerations and dimensional analysis are needed in order to reduce risks to an acceptable level.

  8. A flow path model for regional water distribution optimization

    NASA Astrophysics Data System (ADS)

    Cheng, Wei-Chen; Hsu, Nien-Sheng; Cheng, Wen-Ming; Yeh, William W.-G.

    2009-09-01

    We develop a flow path model for the optimization of a regional water distribution system. The model simultaneously describes a water distribution system in two parts: (1) the water delivery relationship between suppliers and receivers and (2) the physical water delivery network. In the first part, the model considers waters from different suppliers as multiple commodities. This helps the model clearly describe water deliveries by identifying the relationship between suppliers and receivers. The physical part characterizes a physical water distribution network by all possible flow paths. The flow path model can be used to optimize not only the suppliers to each receiver but also their associated flow paths for supplying water. This characteristic leads to the optimum solution that contains the optimal scheduling results and detailed information concerning water distribution in the physical system. That is, the water rights owner, water quantity, water location, and associated flow path of each delivery action are represented explicitly in the results rather than merely as an optimized total flow quantity in each arc of a distribution network. We first verify the proposed methodology on a hypothetical water distribution system. Then we apply the methodology to the water distribution system associated with the Tou-Qian River basin in northern Taiwan. The results show that the flow path model can be used to optimize the quantity of each water delivery, the associated flow path, and the water trade and transfer strategy.

  9. Factors Affecting Nitrate Delivery to Streams from Shallow Ground Water in the North Carolina Coastal Plain

    USGS Publications Warehouse

    Harden, Stephen L.; Spruill, Timothy B.

    2008-01-01

    An analysis of data collected at five flow-path study sites between 1997 and 2006 was performed to identify the factors needed to formulate a comprehensive program, with a focus on nitrogen, for protecting ground water and surface water in the North Carolina Coastal Plain. Water-quality protection in the Coastal Plain requires the identification of factors that affect the transport of nutrients from recharge areas to streams through the shallow ground-water system. Some basins process or retain nitrogen more readily than others, and the factors that affect nitrogen processing and retention were the focus of this investigation to improve nutrient management in Coastal Plain streams and to reduce nutrient loads to coastal waters. Nitrate reduction in ground water was observed at all five flow-path study sites in the North Carolina Coastal Plain, although the extent of reduction at each site was influenced by various environmental, hydrogeologic, and geochemical factors. Denitrification was the most common factor responsible for decreases in nitrate along the ground-water flow paths. Specific factors, some of which affect denitrification rates, that appeared to influence ground-water nitrate concentrations along the flow paths or in the streams include soil drainage, presence or absence of riparian buffers, evapotranspiration, fertilizer use, ground-water recharge rates and residence times, aquifer properties, subsurface tile drainage, sources and amounts of organic matter, and hyporheic processes. The study data indicate that the nitrate-reducing capacity of the buffer zone combined with that of the hyporheic zone can substantially lower the amount of ground-water nitrate discharged to streams in agricultural settings of the North Carolina Coastal Plain. At the watershed scale, the effects of ground-water discharge on surface-water quality appear to be greatly influenced by streamflow conditions and the presence of extensive riparian vegetation. Streamflow statistics

  10. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

    In November 1987, P.E.I. signed a federal/provincial work-sharing arrangement on water resource management focusing on groundwater pollution, surface water degradation and estuarine eutrophication. The surface water program was designed to identify current surface water uses and users within 12 major watersheds across the Island containing 26 individual rivers, as well as problems arising due to practices that degrade the quality of surface water and restricts its value to other user groups. This report presents a general overview of the program, covering the general characteristics of the Island; operations in agriculture, fish and wildlife, forestry, recreation, fisheries, and industry; alterations of natural features of waterways; wetlands; additional watershed activities such as hydrometric stations and subdivision development; and activities affecting surface water resources such as sedimentation sources, pollution point sources and instream obstructions.

  11. Survey of state water laws affecting coal slurry pipeline development

    SciTech Connect

    Rogozen, M.B.

    1980-11-01

    This report summarizes state water laws likely to affect the development of coal slurry pipelines. It was prepared as part of a project to analyze environmental issues related to energy transportation systems. Coal slurry pipelines have been proposed as a means to expand the existing transportation system to handle the increasing coal shipments that will be required in the future. The availability of water for use in coal slurry systems in the coal-producing states is an issue of major concern.

  12. Oil-water flow in vertical and deviated wells

    NASA Astrophysics Data System (ADS)

    Flores, Jose Gonzalo

    1997-08-01

    Oil-water flow in vertical and inclined pipes has been investigated theoretically and experimentally to identify and characterize the flow patterns, and to model the flow pattern transitions, holdup and pressure drop for conditions pertinent to oil-water producing wells. A comprehensive new oil-water flow pattern classification is proposed based on data acquired in a transparent test section (2 in. ID, 51 ft long) using a mineral oil and water (ρo/ρw = 0.85, μo/μw = 20.0 and σo-w = 33.5 dyne/cm at 90oF). The tests covered inclination angles of 90o, 75o, 60o and 45o from the horizontal. The oil-water flow patterns have been grouped into two major categories based on the status of the continuous phase, including water dominated and oil dominated flow patterns. Water dominated flow patterns generally show significant slippage but relatively low frictional pressure gradients. In contrast, oil dominated flow patterns show negligible slippage but significantly large frictional pressure gradients. Six flow patterns have been characterized in vertical flow, three were water dominated and three were oil dominated. In inclined flow there were also three water dominated flow patterns, three oil dominated and a transitional flow pattern. Flow pattern maps for each of the tested inclination angles are presented. Flow parameters, including frictional pressure drop, holdup and spatial phase distribution are functions of the oil-water flow patterns and can be effectively used in flow pattern identification. A newly designed conductance probe assisted significantly in the objective identification of the oil-water flow patterns. Mechanistic models are proposed to predict oil-water flow pattern transitions, and to calculate water holdup and pressure drop in vertical wells. The transitions to very fine dispersed flows were evaluated by combining the turbulent kinetic energy with the surface free energy of the droplets, while the transition to churn flow was predicted based on the

  13. Ground-water flow and water quality in the sand aquifer of Long Beach Peninsula, Washington

    USGS Publications Warehouse

    Thomas, B.E.

    1995-01-01

    This report describes a study that was undertaken to improve the understanding of ground-water flow and water quality in the coastal sand aquifer of the Long Beach Peninsula of southwestern Washington. Data collected for the study include monthly water levels at 103 wells and 28 surface-water sites during 1992, and water-quality samples from about 40 wells and 13 surface-water sites in February and July 1992. Ground water generally flows at right angles to a ground-water divide along the spine of the low-lying peninsula. Historical water-level data indicate that there was no long-term decline in the water table from 1974 to 1992. The water quality of shallow ground water was generally good with a few local problems. Natural concentrations of dissolved iron were higher than 0.3 milligrams per liter in about one-third of the samples. The dissolved-solids concentrations were generally low, with a range of 56 to 218 milligrams per liter. No appreciable amount of seawater has intruded into the sand aquifer, chloride concentrations were low, with a maximum of 52 milligrams per liter. Agricultural activities do not appear to have significantly affected the quality of ground water. Concentrations of nutrients were low in the cranberry-growing areas, and selected pesticides were not found above the analytical detection limits. Septic systems probably caused an increase in the concentration of nitrate from medians of less than 0.05 milligrams per liter in areas of low population density to 0.74 milligrams per liter in areas of high density.

  14. Data assimilation with soil water content sensors and pedotransfer functions in soil water flow modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water flow models are based on a set of simplified assumptions about the mechanisms, processes, and parameters of water retention and flow. That causes errors in soil water flow model predictions. Soil water content monitoring data can be used to reduce the errors in models. Data assimilation (...

  15. The chemistry of salt-affected soils and waters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of the chemistry of salt affected soils and waters is necessary for management of irrigation in arid and semi-arid regions. In this chapter we review the origin of salts in the landscape, the major chemical reactions necessary for prediction of the soil solution composition, and the use of...

  16. Simulation of water flow in terrestrial systems

    2008-12-18

    ParFlow is a parallel, variabley saturated groundwater flow code that is especially suitable for large scale problem. ParFlow simulates the three-dimensional saturated and variably saturated subsurface flow in heterogeneous porous media in three spatial dimensions. ParFlow's developemt and appkication has been on-ging for more than 10 uear. ParFlow has recently been extended to coupled surface-subsurface flow to enabel the simulation of hillslope runoff and channel routing in a truly integrated fashion. ParFlow simulates the three-dimensionalmore » varably saturated subsurface flow in strongly heterogeneous porous media in three spatial dimension.« less

  17. Quantifying Irrigation Return Flows Using Stable Isotopes of Water along the South Platte River, Colorado USA

    NASA Astrophysics Data System (ADS)

    Sanford, W. E.; Davila Olmo, K.; Stednick, J. D.

    2011-12-01

    As the South Platte River flows from Denver, CO to the Nebraska border it crosses urban and agricultural settings which affect water quality and quantity. This reach of the river is highly regulated, with numerous diversions, off-channel reservoirs, and flow-augmentation projects. Water in the river is used 7 different times between Denver and the state line. Much of the water diverted from the river is used for irrigation. A significant portion of this water returns to the river as groundwater flow, often during times of low stream flow. Groundwater return flows, coupled with wastewater treatment plant and reservoir storage, have turned the once ephemeral river into a perennial one. The goal of this research was to determine if the stable isotopes of water (δ 2H and δ18O) in the river can be used to identify and to help quantify groundwater return flows to the river. Water samples were collected and analyzed for their isotopic signature at 17 sites from Denver to Julesburg. Nine rounds of samples were collected from June 2009 to June 2010. Well defined linear patterns of isotope ratios are observed on individual sampling events indicating that the water in the river is becoming enriched as it moves downstream. The enrichment is caused by evaporation from irrigation waters and their discharge to the river as groundwater return flows. These promising results indicate that it may be possible to quantify irrigation return flow to the South Platte River using the stable isotopes of water.

  18. Global water resources affected by human interventions and climate change.

    PubMed

    Haddeland, Ingjerd; Heinke, Jens; Biemans, Hester; Eisner, Stephanie; Flörke, Martina; Hanasaki, Naota; Konzmann, Markus; Ludwig, Fulco; Masaki, Yoshimitsu; Schewe, Jacob; Stacke, Tobias; Tessler, Zachary D; Wada, Yoshihide; Wisser, Dominik

    2014-03-01

    Humans directly change the dynamics of the water cycle through dams constructed for water storage, and through water withdrawals for industrial, agricultural, or domestic purposes. Climate change is expected to additionally affect water supply and demand. Here, analyses of climate change and direct human impacts on the terrestrial water cycle are presented and compared using a multimodel approach. Seven global hydrological models have been forced with multiple climate projections, and with and without taking into account impacts of human interventions such as dams and water withdrawals on the hydrological cycle. Model results are analyzed for different levels of global warming, allowing for analyses in line with temperature targets for climate change mitigation. The results indicate that direct human impacts on the water cycle in some regions, e.g., parts of Asia and in the western United States, are of the same order of magnitude, or even exceed impacts to be expected for moderate levels of global warming (+2 K). Despite some spread in model projections, irrigation water consumption is generally projected to increase with higher global mean temperatures. Irrigation water scarcity is particularly large in parts of southern and eastern Asia, and is expected to become even larger in the future. PMID:24344275

  19. Global water resources affected by human interventions and climate change

    PubMed Central

    Haddeland, Ingjerd; Heinke, Jens; Biemans, Hester; Eisner, Stephanie; Flörke, Martina; Hanasaki, Naota; Konzmann, Markus; Ludwig, Fulco; Masaki, Yoshimitsu; Schewe, Jacob; Stacke, Tobias; Tessler, Zachary D.; Wada, Yoshihide; Wisser, Dominik

    2014-01-01

    Humans directly change the dynamics of the water cycle through dams constructed for water storage, and through water withdrawals for industrial, agricultural, or domestic purposes. Climate change is expected to additionally affect water supply and demand. Here, analyses of climate change and direct human impacts on the terrestrial water cycle are presented and compared using a multimodel approach. Seven global hydrological models have been forced with multiple climate projections, and with and without taking into account impacts of human interventions such as dams and water withdrawals on the hydrological cycle. Model results are analyzed for different levels of global warming, allowing for analyses in line with temperature targets for climate change mitigation. The results indicate that direct human impacts on the water cycle in some regions, e.g., parts of Asia and in the western United States, are of the same order of magnitude, or even exceed impacts to be expected for moderate levels of global warming (+2 K). Despite some spread in model projections, irrigation water consumption is generally projected to increase with higher global mean temperatures. Irrigation water scarcity is particularly large in parts of southern and eastern Asia, and is expected to become even larger in the future. PMID:24344275

  20. Direct numerical simulation of solidification microstructures affected by fluid flow

    SciTech Connect

    Juric, D.

    1997-12-01

    The effects of fluid flow on the solidification morphology of pure materials and solute microsegregation patterns of binary alloys are studied using a computational methodology based on a front tracking/finite difference method. A general single field formulation is presented for the full coupling of phase change, fluid flow, heat and solute transport. This formulation accounts for interfacial rejection/absorption of latent heat and solute, interfacial anisotropies, discontinuities in material properties between the liquid and solid phases, shrinkage/expansion upon solidification and motion and deformation of the solid. Numerical results are presented for the two dimensional dendritic solidification of pure succinonitrile and the solidification of globulitic grains of a plutonium-gallium alloy. For both problems, comparisons are made between solidification without fluid flow and solidification within a shear flow.

  1. Acupuncture affects regional blood flow in various organs.

    PubMed

    Uchida, Sae; Hotta, Harumi

    2008-06-01

    In this review, our recent studies using anesthetized animals concerning the neural mechanisms of vasodilative effect of acupuncture-like stimulation in various organs are briefly summarized. Responses of cortical cerebral blood flow and uterine blood flow are characterized as non-segmental and segmental reflexes. Among acupuncture-like stimuli delivered to five different segmental areas of the body; afferent inputs to the brain stem (face) and to the spinal cord at the cervical (forepaw), thoracic (chest or abdomen), lumbar (hindpaw) and sacral (perineum) levels, cortical cerebral blood flow was increased by stimuli to face, forepaw and hindpaw. The afferent pathway of the responses is composed of somatic groups III and IV afferent nerves and whose efferent nerve pathway includes intrinsic cholinergic vasodilators originating in the basal forebrain. Uterine blood flow was increased by cutaneous stimulation of the hindpaw and perineal area, with perineal predominance. The afferent pathway of the response is composed of somatic group II, III and IV afferent nerves and the efferent nerve pathway includes the pelvic parasympathetic cholinergic vasodilator nerves. Furthermore, we briefly summarize vasodilative regulation of skeletal muscle blood flow via a calcitonin gene-related peptide (CGRP) induced by antidromic activation of group IV somatic afferent nerves. These findings in healthy but anesthetized animals may be applicable to understanding the neural mechanisms improving blood flow in various organs following clinical acupuncture. PMID:18604254

  2. Experimental study of choking flow of water at supercritical conditions

    NASA Astrophysics Data System (ADS)

    Muftuoglu, Altan

    Future nuclear reactors will operate at a coolant pressure close to 25 MPa and at outlet temperatures ranging from 500°C to 625°C. As a result, the outlet flow enthalpy in future Supercritical Water-Cooled Reactors (SCWR) will be much higher than those of actual ones which can increase overall nuclear plant efficiencies up to 48%. However, under such flow conditions, the thermal-hydraulic behavior of supercritical water is not fully known, e.g., pressure drop, forced convection and heat transfer deterioration, critical and blowdown flow rate, etc. Up to now, only a very limited number of studies have been performed under supercritical conditions. Moreover, these studies are conducted at conditions that are not representative of future SCWRs. In addition, existing choked flow data have been collected from experiments at atmospheric discharge pressure conditions and in most cases by using working fluids different than water which constrain researchers to analyze the data correctly. In particular, the knowledge of critical (choked) discharge of supercritical fluids is mandatory to perform nuclear reactor safety analyses and to design key mechanical components (e.g., control and safety relief valves, etc.). Hence, an experimental supercritical water facility has been built at Ecole Polytechnique de Montreal which allows researchers to perform choking flow experiments under supercritical conditions. The facility can also be used to carry out heat transfer and pressure drop experiments under supercritical conditions. In this thesis, we present the results obtained at this facility using a test section that contains a 1 mm inside diameter, 3.17 mm long orifice plate with sharp edges. Thus, 545 choking flow of water data points are obtained under supercritical conditions for flow pressures ranging from 22.1 MPa to 32.1 MPa, flow temperatures ranging from 50°C to 502°C and for discharge pressures from 0.1 MPa to 3.6 MPa. Obtained data are compared with the data given in

  3. Particle manipulation affected by streaming flows in vertically actuated open rectangular chambers

    NASA Astrophysics Data System (ADS)

    Agrawal, Prashant; Gandhi, Prasanna S.; Neild, Adrian

    2016-03-01

    Particle movement in vibration assisted microfluidic systems is significantly affected by time-averaged streaming flows. These flows can demonstrate either particle collection or dispersion characteristics, depending on the parameters used and system specifics. Here we investigate particle collection within streaming flows in vertically actuated open rectangular chambers at frequencies in the range of 100 Hz. Capillary waves, created at the water-air interface under the action of low frequency vibration, generate streaming fields in the liquid bulk. In addition, the spatial variation in the flow field gives rise to particle collection due to inertial effects. In order to understand the interplay between these effects, 2D simulations are employed to understand the first order field induced particle collection, while an experimental study is performed to investigate the effect of the 3D streaming fields on particle motion. By altering the chamber dimensions, two observations are presented: first by taking measures to reduce the strength of the streaming field, particles as small as 50 nm in diameter can be collected. Second, the streaming fields themselves can be used to trap particles, which in conjunction with the collection forces can cause particle separation.

  4. Field monitoring of water flow and solute transport under different manure amendments.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic matter (OM) affects water flow and solute transport in the vadose zone. The main objective of this work was to study the effects of different OM types (dairy and chicken manure), rates (O, 168, 336, and 672 kg/ha total equivalent Nitrogen), and levels (one and two time applications) on water...

  5. Effects of ground-water chemistry and flow on quality of drainflow in the western San Joaquin Valley, California

    USGS Publications Warehouse

    Fio, John L.; Leighton, David A.

    1994-01-01

    Chemical and geohydrologic data were used to assess the effects of regional ground-water flow on the quality of on-farm drainflows in a part of the western San Joaquin Valley, California. Shallow ground water beneath farm fields has been enriched in stable isotopes and salts by partial evaporation from the shallow water table and is being displaced by irrigation, drainage, and regional ground-water flow. Ground-water flow is primarily downward in the study area but can flow upward in some down- slope areas. Transitional areas exist between the downward and upward flow zones, where ground water can move substantial horizontal distances (0.3 to 3.6 kilometers) and can require 10 to 90 years to reach the downslope drainage systems. Simulation of ground-water flow to drainage systems indicates that regional ground water contributes to about 11 percent of annual drainflow. Selenium concentrations in ground water and drainwater are affected by geologic source materials, partial evaporation from a shallow water table, drainage-system, and regional ground-water flow. Temporal variability in drainflow quality is affected in part by the distribution of chemical constituents in ground water and the flow paths to the drainage systems. The mass flux of selenium in drainflows, or load, generally is proportional to flow, and reductions in drainflow quantity should reduce selenium loads over the short-term. Uncertain changes in the distribution of ground-water quality make future changes in drainflow quality difficult to quantify.

  6. Nonintrusive Flow Rate Determination Through Space Shuttle Water Coolant Loop Floodlight Coldplate

    NASA Technical Reports Server (NTRS)

    Werlink, Rudolph; Johnson, Harry; Margasahayam, Ravi

    1997-01-01

    Using a Nonintrusive Flow Measurement System (NFMS), the flow rates through the Space Shuttle water coolant coldplate were determined. The objective of this in situ flow measurement was to prove or disprove a potential block inside the affected coldplate had contributed to a reduced flow rate and the subsequent ice formation on the Space Shuttle Discovery. Flow through the coldplate was originally calculated to be 35 to 38 pounds per hour. This application of ultrasonic technology advanced the envelope of flow measurements through use of 1/4-inch-diameter tubing, which resulted in extremely low flow velocities (5 to 30 pounds per hour). In situ measurements on the orbiters Discovery and Atlantis indicated both vehicles, on the average, experienced similar flow rates through the coldplate (around 25 pounds per hour), but lower rates than the designed flow. Based on the noninvasive checks, further invasive troubleshooting was eliminated. Permanent monitoring using the NFMS was recommended.

  7. The uncertainty effects of design flow on water quality management.

    PubMed

    Chen, Chi-Feng; Ma, Hwong-Wen

    2008-09-01

    In water quality management, pollution control strategies have been sought to accord with the assimilative capacity of water bodies so as to preserve water quality. The waste load allocation (WLA) is a useful approach to determine the allowable loading of pollution sources in water quality management. For any WLA, a particular water body condition is needed as a basic scenario under which the relevant parameters are fixed. The particular flow rate is known as design flow and usually set at low flow in order to be protective. The design flow is traditionally a particular deterministic value, such as Q (75), implying that it is expected that the probability of water quality violation is 25% in the long run. However, this long-term expectation might not be realized in individual years due to variability of natural flow. The flow variability will make a WLA plan overoptimistic or over-conservative in different years, suggesting that the deterministic design flow without uncertainty consideration might lead to an ineffective or inefficient decision-making. To address the problem, we explicate the relationship between flow variability, design flow and water quality with different flow distributions to facilitate the understanding of the process of a WLA. In order to manifest the uncertainty effects of design flow, the results from the annual flow duration curve (AFDC) is compared with the conventional flow duration curve (FDC). The AFDC approach is capable of obtaining the uncertainty level of the design flow by generating the confidence interval rather than a fixed value. The effect of different record lengths on design flow determination is estimated as well. Finally, a refined WLA process is proposed with a re-examination of water quality violation to improve the allocation decision under uncertainty. TaHan River Basin in northern Taiwan is used as a case study. PMID:17891466

  8. Guidelines for Evaluating Ground-Water Flow Models

    USGS Publications Warehouse

    Reilly, Thomas E.; Harbaugh, Arlen W.

    2004-01-01

    Ground-water flow modeling is an important tool frequently used in studies of ground-water systems. Reviewers and users of these studies have a need to evaluate the accuracy or reasonableness of the ground-water flow model. This report provides some guidelines and discussion on how to evaluate complex ground-water flow models used in the investigation of ground-water systems. A consistent thread throughout these guidelines is that the objectives of the study must be specified to allow the adequacy of the model to be evaluated.

  9. Accounting for environmental flow requirements in global water assessments

    NASA Astrophysics Data System (ADS)

    Pastor, A. V.; Ludwig, F.; Biemans, H.; Hoff, H.; Kabat, P.

    2014-12-01

    As the water requirement for food production and other human needs grows, quantification of environmental flow requirements (EFRs) is necessary to assess the amount of water needed to sustain freshwater ecosystems. EFRs are the result of the quantification of water necessary to sustain the riverine ecosystem, which is calculated from the mean of an environmental flow (EF) method. In this study, five EF methods for calculating EFRs were compared with 11 case studies of locally assessed EFRs. We used three existing methods (Smakhtin, Tennant, and Tessmann) and two newly developed methods (the variable monthly flow method (VMF) and the Q90_Q50 method). All methods were compared globally and validated at local scales while mimicking the natural flow regime. The VMF and the Tessmann methods use algorithms to classify the flow regime into high, intermediate, and low-flow months and they take into account intra-annual variability by allocating EFRs with a percentage of mean monthly flow (MMF). The Q90_Q50 method allocates annual flow quantiles (Q90 and Q50) depending on the flow season. The results showed that, on average, 37% of annual discharge was required to sustain environmental flow requirement. More water is needed for environmental flows during low-flow periods (46-71% of average low-flows) compared to high-flow periods (17-45% of average high-flows). Environmental flow requirements estimates from the Tennant, Q90_Q50, and Smakhtin methods were higher than the locally calculated EFRs for river systems with relatively stable flows and were lower than the locally calculated EFRs for rivers with variable flows. The VMF and Tessmann methods showed the highest correlation with the locally calculated EFRs (R2=0.91). The main difference between the Tessmann and VMF methods is that the Tessmann method allocates all water to EFRs in low-flow periods while the VMF method allocates 60% of the flow in low-flow periods. Thus, other water sectors such as irrigation can withdraw

  10. Three-dimensional freezing of flowing water in a tube cooled by air flow

    NASA Astrophysics Data System (ADS)

    Sugawara, M.; Komatsu, Y.; Beer, H.

    2015-05-01

    The 3-D freezing of flowing water in a copper tube cooled by air flow is investigated by means of a numerical analysis. The air flows normal to the tube axis. Several parameters as inlet water mean velocity w m , inlet water temperature T iℓ t , air flow temperature T a and air flow velocity u a are selected in the calculations to adapt it to a winter season actually encountered. The numerical results present the development of the ice layer mean thickness and its 3-D morphologies as well as the critical ice layer thickness in the tube choked by the ice layer.

  11. Application of Neutron Radiography to Flow Visualization in Supercritical Water

    NASA Astrophysics Data System (ADS)

    Takenaka, N.; Sugimoto, K.; Takami, S.; Sugioka, K.; Tsukada, T.; Adschiri, T.; Saito, Y.

    Supercritical water is used in various chemical reaction processes including hydrothermal synthesis of metal oxide nano-particles, oxidation, chemical conversion of biomass and plastics. Density of the super critical water is much less than that of the sub-critical water. By using neutron radiography, Peterson et al. have studied salt precipitation processes in supercritical water and the flow pattern in a reverse-flow vessel for salt precipitation, and Balasko et al. have revealed the behaviour of supercritical water in a container. The nano-particles were made by mixing the super critical flow and the sub critical water solution. In the present study, neutron radiography was applied to the flow visualization of the super and sub critical water mixture in a T-junction made of stainless steel pipes for high pressure and temperature conditions to investigate their mixing process. Still images by a CCD camera were obtained by using the neutron radiography system at B4 port in KUR.

  12. Hydraulic contacts controlling water flow across porous grains

    NASA Astrophysics Data System (ADS)

    Carminati, A.; Kaestner, A.; Flühler, H.; Lehmann, P.; Or, D.; Lehmann, E.; Stampanoni, M.

    2007-08-01

    Water flow between porous grains varies widely depending on the water distribution in contacts between grains. The hydraulic behavior of contacts varies from highly conductive when water fills the contacts to a bottleneck to flow as water pressure drops and contact asperities rapidly drain. Such changes greatly impact the hydraulic conductivity of porous grain packs such as aggregated soil. The dominant driving force of water flow across contacts is capillarity, often quantified relative to gravity and viscous forces using the capillary and Bond numbers. For fast water infiltration, viscous forces dominate. For simplicity we modeled the water distribution between spherical porous grains whose surfaces are covered by spherical bumps of much smaller radii. We provide experimental evidence obtained by neutron radiography and synchrotron-based x-ray tomographic microscopy documenting transitions in the flow behavior across contacts.

  13. CONCEPTUAL FRAMEWORK FOR REGRESSION MODELING OF GROUND-WATER FLOW.

    USGS Publications Warehouse

    Cooley, Richard L.

    1985-01-01

    The author examines the uses of ground-water flow models and which classes of use require treatment of stochastic components. He then compares traditional and stochastic procedures for modeling actual (as distinguished from hypothetical) systems. Finally, he examines the conceptual basis and characteristics of the regression approach to modeling ground-water flow.

  14. 49 CFR 229.111 - Water-flow indicator.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.111 Water-flow indicator. (a) Steam generators shall be equipped with an illuminated visual return water-flow indicator. (b) Steam generators shall be equipped with an operable test valve or other...

  15. Gas/oil/water flow measurement by electrical capacitance tomography

    NASA Astrophysics Data System (ADS)

    Li, Yi; Yang, Wuqiang; Xie, Cheng-gang; Huang, Songming; Wu, Zhipeng; Tsamakis, Dimitrios; Lenn, Chris

    2013-07-01

    In the oil industry, it is important to measure gas/oil/water flows produced from oil wells. To determine oil production, it is necessary to measure the water-in-liquid ratio (WLR), liquid fraction and some other parameters, which are related to multiphase flow rates. A research team from the University of Manchester and Schlumberger Gould Research have developed an experimental apparatus for gas/oil/water flow measurement based on a flow-conditioning device and electrical capacitance tomography (ECT) and microwave sensors. This paper presents the ECT part of the developed apparatus, including the re-engineering of an ECT sensor and a model-based image reconstruction algorithm, which is used to derive the WLR and the thickness of the liquid layer in oil-continuous annular flows formed by the flow-conditioning device. The ECT sensor was tested both at Schlumberger and on TUV-NEL's Multiphase Flow Facility. The experimental results are promising.

  16. What part of natural flow can be considered a "water resource"?

    NASA Astrophysics Data System (ADS)

    Andréassian, V.; Margat, J.; Thirel, G.; Hubert, P.

    2015-04-01

    In this paper, we discuss an unfortunate semantic shortcut - the use of the expression "water resources" as a synonym for "river/groundwater flow" - which causes great confusion in all Water Security-related discussions. We show that only a part of the flow can be considered a resource, and that the efficiency of the flow-to-resource conversion is a complex function of: (i) the hydrologic regime, (ii) environmental constraints (in-stream reserved flows), (iii) the type of water demand, and (iv) the existence of artificial reservoirs. Last, we illustrate how the flow-to-resource conversion can be affected by future climatic changes. Hydrologic data and climate change simulations for three French rivers (the rivers Vilaine, Durance and Garonne) are used to illustrate this discussion.

  17. Vortex breakdown in a water-spout flow

    NASA Astrophysics Data System (ADS)

    Herrada, Miguel A.; Shtern, Vladimir N.; López-Herrera, José María

    2013-09-01

    The numerical study of the steady axisymmetric air-water flow in a vertical sealed cylinder, driven by the rotating top disk, describes topological transformations as the rotation intensifies. The air meridional flow (AMF) and swirl induce meridional motions of opposite directions in water. For slow (fast) rotation, the effect of AMF (swirl) dominates. For very fast rotation, large-scale regions of clockwise meridional circulation in air and water are separated by a thin layer of anticlockwise circulation adjacent to the interface in water. This pattern develops for other fluids as well. Physical reasoning behind the flow evolution is provided.

  18. Flow separation of currents in shallow water

    USGS Publications Warehouse

    Signell, Richard P.

    1989-01-01

    Flow separation of currents in shallow coastal areas is investigated using a boundary layer model for two-dimensional (depth-averaged) tidal flow past an elliptic headland. If the shoaling region near the coast is narrow compared to the scale of the headland, bottom friction causes the flow to separate just downstream of the point where the pressure gradient switches from favoring to adverse. As long as the shoaling region at the coast is well resolved, the inclusion of eddy viscosity and a no-slip boundary condition have no effect on this result. An approximate analytic solution for the pressure gradient along the boundary is obtained by assuming the flow away from the immediate vicinity of the boundary is irrotational. On the basis of the pressure gradient obtained from the irrotational flow solution, flow separation is a strong function of the headland aspect ratio, an equivalent Reynolds number, and a Keulegan-Carpenter number.

  19. Water infiltration and intermittent flow in rough-walled fractures

    SciTech Connect

    Su, G.

    1995-05-01

    Flow visualization experiments were conducted in transparent replicas of natural rough-walled fractures. The fracture was inclined to observe the interplay between capillary and gravity forces. Water was introduced into the fracture by a capillary siphon. Preferential flow paths were observed, where intermittent flow frequently occurred. The water infiltration experiments suggest that intermittent flow in fractures appears to be the rule rather than the exception. In order to investigate the mechanism causing intermittent flow in fractures, parallel plates with different apertures were assembled using lucite and glass. A medium-coarse-fine pore structure is believed to cause the intermittency in flow. Intermittent flow was successfully produced in the parallel plate experiments using the lucite plates. After several trials, intermittent flow was also produced in the glass plates.

  20. Compartment in vertical flow reactor for ferruginous mine water

    NASA Astrophysics Data System (ADS)

    Hur, Won; Cheong, Young-Wook; Yim, Gil-Jae; Ji, Sang-Woo; Hong, Ji-Hye

    2014-05-01

    Mine effluents contain varying concentrations of ferrous ion along with other metal ions. Fe(II) that quickly oxidizes to form precipitates in the presence of oxygen under net alkaline or neutral conditions. Thus, passive treatment methods are designed for the mine water to reside in an open containment area so as to allow simultaneous oxidation and precipitation of Fe(II), such as in a lagoon or an oxidation pond. A vertical flow reactor (VFR) was also suggested to remediate ferruginous mine drainage passing down through an accreting bed of ochre. However, VFR has a limited operation time until the system begins to overflow. It was also demonstrated that two-compartment VFR has a longer operation time than single compartment VFR of same size. In this study, a mathematical model was developed as a part of efforts to explore the operation of VFR, showing dynamic changes in head differences, ochre depth and Fe(II)/Fe(III) concentration in the effluent flow. The analysis shows that Fe(II) oxidation and ochre formation should be balanced with permeability of ochre bed to maximize VFR operation time and minimize residual Fe(II) in the effluent. The model demonstrates that two compartment VFR can have a longer operation time than a single-compartment VFR and that an optimum compartment ratio exists that maximize VFR operation time. Accelerated Fe(II) oxidation significantly affects the optimum ratio of compartment area and reduced residual Fe(II) in the effluent. VFR operation time can be significantly prolonged by increasing the rate of ochre formation not by accelerated Fe(II) oxidation. Taken together, ochre forms largely in the first compartment while overflowed mine water with reduced iron contents is efficiently filtered in the second compartment. These results provide us a better understanding of VFR operation and optimum design criteria for maximum operation time in a two-compartment VFR. Rapid ochre accretion in the first compartment maintains constant hydraulic

  1. On the Origin of Water Flow through Carbon Nanotubes.

    PubMed

    Su, Jiaye; Yang, Keda

    2015-11-16

    The transport of water molecules through carbon nanotubes (CNTs) is of primary importance for understanding water-mediated biological activities as well as for the design of novel nanoporous materials. Herein, we analyze the water flow through CNTs by using molecular dynamics simulations with the hope of finding basic parameters determining the flow value. Of particular interest is that a simple equation as a function of water diffusion, occupancy and CNT size, can well describe the water flow through CNTs with different sizes. Specifically, both the simulation and equation flow exhibit power law relations with the CNT diameter and length, where the two exponents are close to each other. The water occupancy and translocation time also demonstrate interesting relations with the CNT size. The water dipole orientations and density profiles are also sensitive to the change of CNT size. These results greatly enhance our knowledge on the nature of water flow through CNTs and are helpful in predicting the water flow of CNTs up to the experimental length scale. PMID:26346506

  2. Trading water to improve environmental flow outcomes

    NASA Astrophysics Data System (ADS)

    Connor, Jeffery D.; Franklin, Brad; Loch, Adam; Kirby, Mac; Wheeler, Sarah Ann

    2013-07-01

    As consumptive extractions and water scarcity pressures brought about by climate change increase in many world river basins, so do the risks to water-dependent ecological assets. In response, public or not for profit environmental water holders (EWHs) have been established in many areas and bestowed with endowments of water and mandates to manage water for ecological outcomes. Water scarcity has also increasingly spawned water trade arrangements in many river basins, and in many instances, EWHs are now operating in water markets. A number of EWHs, especially in Australia, begin with an endowment of permanent water entitlements purchased from irrigators. Such water entitlements typically have relatively constant interannual supply profiles that often do not match ecological water demand involving flood pulses and periods of drying. This article develops a hydrologic-economic simulation model of the Murrumbidgee catchment within the Murray-Darling Basin to assess the scope of possibilities to improve environmental outcomes through EWH trading on an annual water lease market. We find that there are some modest opportunities for EWHs to improve environmental outcomes through water trade. The best opportunities occur in periods of drought and for ecological outcomes that benefit from moderately large floods. We also assess the extent to which EWH trading in annual water leases may create pecuniary externalities via bidding up or down the water lease prices faced by irrigators. Environmental water trading is found to have relatively small impacts on water market price outcomes. Overall our results suggest that the benefits of developing EWH trading may well justify the costs.

  3. Adaptive hydrological flow field modeling based on water body extraction and surface information

    NASA Astrophysics Data System (ADS)

    Puttinaovarat, Supattra; Horkaew, Paramate; Khaimook, Kanit; Polnigongit, Weerapong

    2015-01-01

    Hydrological flow characteristic is one of the prime indicators for assessing flood. It plays a major part in determining drainage capability of the affected basin and also in the subsequent simulation and rainfall-runoff prediction. Thus far, flow directions were typically derived from terrain data which for flat landscapes are obscured by other man-made structures, hence undermining the practical potential. In the absence (or diminutive) of terrain slopes, water passages have a more pronounced effect on flow directions than elevations. This paper, therefore, presents detailed analyses and implementation of hydrological flow modeling from satellite and topographic images. Herein, gradual assignment based on support vector machine was applied to modified normalized difference water index and a digital surface model, in order to ensure reliable water labeling while suppressing modality-inherited artifacts and noise. Gradient vector flow was subsequently employed to reconstruct the flow field. Experiments comparing the proposed scheme with conventional water boundary delineation and flow reconstruction were presented. Respective assessments revealed its advantage over the generic stream burning. Specifically, it could extract water body from studied areas with 98.70% precision, 99.83% recall, 98.76% accuracy, and 99.26% F-measure. The correlations between resultant flows and those obtained from the stream burning were as high as 0.80±0.04 (p≤0.01 in all resolutions).

  4. Flow measurements in a water tunnel using a holocinematographic velocimeter

    NASA Astrophysics Data System (ADS)

    Weinstein, Leonard M.; Beeler, George B.

    1987-06-01

    Dual-view holographic movies were used to examine complex flows with full three-space and time resolution. This approach, which tracks the movement of small tracer particles in water, is termed holocinematographic velocimetry (HCV). A small prototype of a new water tunnel was used to demonstrate proof-of-concept for the HCV. After utilizing a conventional flow visualization apparatus with a laser light sheet to illuminate tracer particles to evaluate flow quality of the prototype tunnel, a simplified version of the HCV was employed to demonstrate the capabilities of the approach. Results indicate that a full-scale version of the water tunnel and a high performance version of the HCV should be able to check theoretical and numerical modeling of complex flows and examine the mechanisms operative in turbulent and vortex flow control concepts, providing an entirely unique instrument capable, for the first time, of simultaneous three-space and time measurements in turbulent flow.

  5. Flow measurements in a water tunnel using a holocinematographic velocimeter

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.; Beeler, George B.

    1987-01-01

    Dual-view holographic movies were used to examine complex flows with full three-space and time resolution. This approach, which tracks the movement of small tracer particles in water, is termed holocinematographic velocimetry (HCV). A small prototype of a new water tunnel was used to demonstrate proof-of-concept for the HCV. After utilizing a conventional flow visualization apparatus with a laser light sheet to illuminate tracer particles to evaluate flow quality of the prototype tunnel, a simplified version of the HCV was employed to demonstrate the capabilities of the approach. Results indicate that a full-scale version of the water tunnel and a high performance version of the HCV should be able to check theoretical and numerical modeling of complex flows and examine the mechanisms operative in turbulent and vortex flow control concepts, providing an entirely unique instrument capable, for the first time, of simultaneous three-space and time measurements in turbulent flow.

  6. Simulating root-induced rhizosphere deformation and its effect on water flow

    NASA Astrophysics Data System (ADS)

    Aravena, J. E.; Ruiz, S.; Mandava, A.; Regentova, E. E.; Ghezzehei, T.; Berli, M.; Tyler, S. W.

    2011-12-01

    Soil structure in the rhizosphere is influenced by root activities, such as mucilage production, microbial activity and root growth. Root growth alters soil structure by moving and deforming soil aggregates, affecting water and nutrient flow from the bulk soil to the root surface. In this study, we utilized synchrotron X-ray micro-tomography (XMT) and finite element analysis to quantify the effect of root-induced compaction on water flow through the rhizosphere to the root surface. In a first step, finite element meshes of structured soil around the root were created by processing rhizosphere XMT images. Then, soil deformation by root expansion was simulated using COMSOL Multiphysics° (Version 4.2) considering the soil an elasto-plastic porous material. Finally, fluid flow simulations were carried out on the deformed mesh to quantify the effect of root-induced compaction on water flow to the root surface. We found a 31% increase in water flow from the bulk soil to the root due to a 56% increase in root diameter. Simulations also show that the increase of root-soil contact area was the dominating factor with respect to the calculated increase in water flow. Increase of inter-aggregate contacts in size and number were observed within a couple of root diameters away from the root surface. But their influence on water flow was, in this case, rather limited compared to the immediate soil-root contact.

  7. An investigation of flow regimes affecting the Mexico City region

    SciTech Connect

    Bossert, J.E.

    1995-05-01

    The Mexico City region is well-known to the meteorological community for its overwhelming air pollution problem. Several factors contribute to this predicament, namely, the 20 million people and vast amount of industry within the city. The unique geographical setting of the basin encompassing Mexico City also plays an important role. This basin covers approximately 5000 km{sup 2} of the Mexican Plateau at an average elevation of 2250 m above sea level (asl) and is surrounded on three sides by mountains averaging over 3500 m asl, with peaks over 5000 m asl. Only to the north is their a significant opening in the mountainous terrain. Mexico City sprawls over 1000 km{sup 2} in the southwestern portion of the basin. In recent years, several major research programs have been undertaken to investigate the air quality problem within Mexico City. One of these, the Mexico City Air Quality Research Initiative (MARI), conducted in 1990--1993, was a cooperative study between researchers at Los Alamos National Laboratory and the Mexican Petroleum Institute. As part of this study, a field campaign was initiated in February 1991 during which numerous surface, upper air, aircraft, and LIDAR measurements were taken. Much of the work to date has focused upon defining and simulating the local meteorological conditions that are important for understanding the complex photochemistry occurring within the confines of the city. It seems reasonable to postulate, however, that flow systems originating outside of the Mexico City basin will influence conditions within the city much of the time.

  8. Idea Cards for Water Flow. Elementary Science Study.

    ERIC Educational Resources Information Center

    Elementary Science Study, Newton, MA.

    Presented are 29 activity cards designed for use with the Elementary Science Study (ESS) program. Each card describes an experiment on one aspect of water flow such as siphoning, methods of removing water from a container, aspirators, floats, and water behavior in various tubing linkups. Activities are intended for individual or small group study;…

  9. Strontium isotope characterization and major ion geochemistry of karst water flow, Shentou, northern China

    NASA Astrophysics Data System (ADS)

    Wang, Yanxin; Guo, Qinghai; Su, Chunli; Ma, Teng

    2006-09-01

    SummaryKarst water is the most important source of water supply for Shanxi province, northern China. The Shentou springs are representative of the 19 major karst springs at Shanxi. The total area of the Shentou karst water system is 5316 km 2, the Middle Ordovician limestone being its major karst aquifer. In this study, data about the strontium isotope geochemistry and major ion hydrochemistry were analyzed to understand the flow patterns and hydrogeochemical processes of karst water at Shentou. The contour map of TDS value of karst water and that of Sr concentration are similar, showing the general tendency of increase from the northern, western and southern boundary to the discharge area. The average values of 87Sr/ 86Sr ratios of karst water decrease from recharge (0.7107) to discharge area (0.7102), evolving towards those of limestone hostrocks. Comparison of 87Sr/ 86Sr ratios with Sr content suggests that isotopic compositions of some karst water samples from the recharge and flow through area should be the result of interaction between aquifer limestone matrix and strontium-poor recharge waters of meteoric origin. However, for samples from the discharge area that are plotted above the mixing line, mixing with groundwater in the Quaternary aquifers with high 87Sr/ 86Sr ratios may be another factor controlling Sr isotope chemistry. Two major groundwater flow paths were discerned from hydrogeological and geochemical data. Along both flow paths, the 87Sr/ 86Sr ratios of karst water show a general tendency of decrease. Geochemical modeling of the major ion geochemistry of karst water using PHREEQC also indicates that the chemistry of springs should be affected by the incorporation of groundwater in Quaternary aquifer. The effect of the mixing action on the spring hydrochemistry in flow path 1 is more remarkable than that in flow path 2, according to different mixing ratios in both paths (30% in flow path 1 and 5% in flow path 2).

  10. River flow changes related to land and water management practices across the conterminous United States.

    PubMed

    Eng, Ken; Wolock, David M; Carlisle, Daren M

    2013-10-01

    The effects of land and water management practices (LWMP)--such as the construction of dams and roads--on river flows typically have been studied at the scale of single river watersheds or for a single type of LWMP. For the most part, assessments of the relative effects of multiple LWMP within many river watersheds across regional and national scales have been lacking. This study assesses flow alteration--quantified as deviation of several flow metrics from natural conditions--at 4196 gauged rivers affected by a variety of LWMP across the conterminous United States. The most widespread causes of flow changes among the LWMP considered were road density and dams. Agricultural development and wastewater discharges also were associated with flow changes in some regions. Dams generally reduced most attributes of flow, whereas road density, agriculture and wastewater discharges tended to be associated with increased flows compared to their natural condition. PMID:23827362

  11. River flow changes related to land and water management practices across the conterminous United States

    USGS Publications Warehouse

    Eng, Ken; Wolock, David M.; Carlisle, Daren M.

    2013-01-01

    The effects of land and water management practices (LWMP)—such as the construction of dams and roads—on river flows typically have been studied at the scale of single river watersheds or for a single type of LWMP. For the most part, assessments of the relative effects of multiple LWMP within many river watersheds across regional and national scales have been lacking. This study assesses flow alteration—quantified as deviation of several flow metrics from natural conditions—at 4196 gauged rivers affected by a variety of LWMP across the conterminous United States. The most widespread causes of flow changes among the LWMP considered were road density and dams. Agricultural development and wastewater discharges also were associated with flow changes in some regions. Dams generally reduced most attributes of flow, whereas road density, agriculture and wastewater discharges tended to be associated with increased flows compared to their natural condition.

  12. Scaling preferential flow processes in agricultural soils affected by tillage and trafficking at the field scale

    NASA Astrophysics Data System (ADS)

    Filipović, Vilim; Coquet, Yves

    2016-04-01

    There is an accumulation of experimental evidences that agricultural soils, at least the top horizons affected by tillage practices, are not homogeneous and present a structure that is strongly dependent on farming practices like tillage and trafficking. Soil tillage and trafficking can create compacted zones in the soil with hydraulic properties and porosity which are different from those of the non-compacted zones. This spatial variability can strongly influence transport processes and initiate preferential flow. Two or three dimensional models can be used to account for spatial variability created by agricultural practices, but such models need a detailed assessment of spatial heterogeneity which can be rather impractical to provide. This logically raises the question whether and how one dimensional model may be designed and used to account for the within-field spatial variability in soil structure created by agricultural practices. Preferential flow (dual-permeability) modelling performed with HYDRUS-1D will be confronted to classical modelling based on the Richards and convection-dispersion equations using HYDRUS-2D taking into account the various soil heterogeneities created by agricultural practices. Our goal is to derive one set of equivalent 1D soil hydraulic parameters from 2D simulations which accounts for soil heterogeneities created by agricultural operations. A field experiment was carried out in two phases: infiltration and redistribution on a plot by uniform sprinkle irrigation with water or bromide solution. Prior to the field experiment the soil structure of the tilled layer was determined along the face of a large trench perpendicular to the tillage direction (0.7 m depth and 3.1 m wide). Thirty TDR probes and tensiometers were installed in different soil structural zones (Δ compacted soil and Γ macroporous soil) which ensured soil water monitoring throughout the experiment. A map of bromide was constructed from small core samples (4 cm diam

  13. Estimating Monthly Water Withdrawals, Return Flow, and Consumptive Use in the Great Lakes Basin

    USGS Publications Warehouse

    Shaffer, Kimberly H.; Stenback, Rosemary S.

    2010-01-01

    Water-resource managers and planners require water-withdrawal, return-flow, and consumptive-use data to understand how anthropogenic (human) water use affects the hydrologic system. Water models like MODFLOW and GSFLOW use calculations and input values (including water-withdrawal and return flow data) to simulate and predict the effects of water use on aquifer and stream conditions. Accurate assessments of consumptive use, interbasin transfer, and areas that are on public supply or sewer are essential in estimating the withdrawal and return-flow data needed for the models. As the applicability of a model to real situations depends on accurate input data, limited or poor water-use data hampers the ability of modelers to simulate and predict hydrologic conditions. Substantial differences exist among the many agencies nationwide that are responsible for compiling water-use data including what data are collected, how the data are organized, how often the data are collected, quality assurance, required level of accuracy, and when data are released to the public. This poster presents water-use information and estimation methods summarized from recent U.S. Geological Survey (USGS) reports with the intent to assist water-resource managers and planners who need estimates of monthly water withdrawals, return flows, and consumptive use. This poster lists references used in Shaffer (2009) for water withdrawals, consumptive use, and return flows. Monthly percent of annual withdrawals and monthly consumptive-use coefficients are used to compute monthly water withdrawals, consumptive use, and return flow for the Great Lakes Basin.

  14. Regression modeling of ground-water flow

    USGS Publications Warehouse

    Cooley, R.L.; Naff, R.L.

    1985-01-01

    Nonlinear multiple regression methods are developed to model and analyze groundwater flow systems. Complete descriptions of regression methodology as applied to groundwater flow models allow scientists and engineers engaged in flow modeling to apply the methods to a wide range of problems. Organization of the text proceeds from an introduction that discusses the general topic of groundwater flow modeling, to a review of basic statistics necessary to properly apply regression techniques, and then to the main topic: exposition and use of linear and nonlinear regression to model groundwater flow. Statistical procedures are given to analyze and use the regression models. A number of exercises and answers are included to exercise the student on nearly all the methods that are presented for modeling and statistical analysis. Three computer programs implement the more complex methods. These three are a general two-dimensional, steady-state regression model for flow in an anisotropic, heterogeneous porous medium, a program to calculate a measure of model nonlinearity with respect to the regression parameters, and a program to analyze model errors in computed dependent variables such as hydraulic head. (USGS)

  15. Water flow modulates the response of coral reef communities to ocean acidification.

    PubMed

    Comeau, S; Edmunds, P J; Lantz, C A; Carpenter, R C

    2014-01-01

    By the end of the century coral reefs likely will be affected negatively by ocean acidification (OA), but both the effects of OA on coral communities and the crossed effects of OA with other physical environmental variables are lacking. One of the least considered physical parameters is water flow, which is surprising considering its strong role in modulating the physiology of reef organisms and communities. In the present study, the effects of flow were tested on coral reef communities maintained in outdoor flumes under ambient pCO2 and high pCO2 (1300 μatm). Net calcification of coral communities, including sediments, was affected by both flow and pCO2 with calcification correlated positively with flow under both pCO2 treatments. The effect of flow was less evident for sediments where dissolution exceeded precipitation of calcium carbonate under all flow speeds at high pCO2. For corals and calcifying algae there was a strong flow effect, particularly at high pCO2 where positive net calcification was maintained at night in the high flow treatment. Our results demonstrate the importance of water flow in modulating the coral reef community response to OA and highlight the need to consider this parameter when assessing the effects of OA on coral reefs. PMID:25327767

  16. Water flow modulates the response of coral reef communities to ocean acidification

    PubMed Central

    Comeau, S.; Edmunds, P. J.; Lantz, C. A.; Carpenter, R. C.

    2014-01-01

    By the end of the century coral reefs likely will be affected negatively by ocean acidification (OA), but both the effects of OA on coral communities and the crossed effects of OA with other physical environmental variables are lacking. One of the least considered physical parameters is water flow, which is surprising considering its strong role in modulating the physiology of reef organisms and communities. In the present study, the effects of flow were tested on coral reef communities maintained in outdoor flumes under ambient pCO2 and high pCO2 (1300 μatm). Net calcification of coral communities, including sediments, was affected by both flow and pCO2 with calcification correlated positively with flow under both pCO2 treatments. The effect of flow was less evident for sediments where dissolution exceeded precipitation of calcium carbonate under all flow speeds at high pCO2. For corals and calcifying algae there was a strong flow effect, particularly at high pCO2 where positive net calcification was maintained at night in the high flow treatment. Our results demonstrate the importance of water flow in modulating the coral reef community response to OA and highlight the need to consider this parameter when assessing the effects of OA on coral reefs. PMID:25327767

  17. Agricultural virtual water flows within the United States

    NASA Astrophysics Data System (ADS)

    Dang, Qian; Lin, Xiaowen; Konar, Megan

    2015-02-01

    Trade plays an increasingly important role in the global food system, which is projected to be strained by population growth, economic development, and climate change. For this reason, there has been a surge of interest in the water resources embodied in international trade, referred to as "global virtual water trade." In this paper, we present a comprehensive assessment of virtual water flows within the United States (U.S.), a country with global importance as a major agricultural producer and trade power. This is the first study of domestic virtual water flows based upon intranational food transfer empirical data and it provides insight into how the properties of virtual water transfers vary across scales. We find that the volume of virtual water flows within the U.S. is equivalent to 51% of international flows, which is slightly higher than the U.S. food value and mass shares, due to the fact that water-intensive meat commodities comprise a much larger fraction of food transfers within the U.S.. The U.S. virtual water flow network is more social, homogeneous, and equitable than the global virtual water trade network, although it is still not perfectly equitable. Importantly, a core group of U.S. States is central to the network structure, indicating that both domestic and international trade may be vulnerable to disruptive climate or economic shocks in these U.S. States.

  18. Enhanced water vapour flow in silica microchannels and interdiffusive water vapour flow through anodic aluminium oxide (AAO) membranes

    NASA Astrophysics Data System (ADS)

    Lei, Wenwen; McKenzie, David R.

    2015-12-01

    Enhanced liquid water flows through carbon nanotubes reinvigorated the study of moisture permeation through membranes and micro- and nano-channels. The study of water vapour through micro-and nano-channels has been neglected even though water vapour is as important as liquid water for industry, especially for encapsulation of electronic devices. Here we measure moisture flow rates in silica microchannels and interdiffusive water vapour flows in anodic aluminium oxide (AAO) membrane channels for the first time. We construct theory for the flow rates of the dominant modes of water transport through four previously defined standard configurations and benchmark it against our new measurements. The findings show that measurements of leak behaviour made using other molecules, such as helium, are not reliable. Single phase water vapour flow is overestimated by a helium measurement, while Washburn or capillary flow is underestimated or for all channels when boundary slip applies, to an extent that depends on the slip length for the liquid phase flows.

  19. Near-surface physics during convection affecting air-water gas transfer

    NASA Astrophysics Data System (ADS)

    Fredriksson, S. T.; Arneborg, L.; Nilsson, H.; Handler, R. A.

    2016-05-01

    The gas flux at the water surface is affected by physical processes including turbulence from wind shear, microscale wave breaking, large-scale breaking, and convection due to heat loss at the surface. The main route in the parameterizations of the gas flux has been to use the wind speed as a proxy for the gas flux velocity, indirectly taking into account the dependency of the wind shear and the wave processes. The interest in the contributions from convection processes has increased as the gas flux from inland waters (with typically lower wind and sheltered conditions) now is believed to play a substantial role in the air-water gas flux budget. The gas flux is enhanced by convection through the mixing of the mixed layer as well as by decreasing the diffusive boundary layer thickness. The direct numerical simulations performed in this study are shown to be a valuable tool to enhance the understanding of this flow configuration often present in nature.

  20. Contrasting discharge computation methods in riverine and tidal-affected flows in Mississippi

    USGS Publications Warehouse

    Turnipseed, D.P.

    2004-01-01

    Recent advancements in acoustic science have improved the measurement of real-time flow conditions in complex open-channel flow systems with dynamic channel geometry, velocity distribution and direction, and other gradually varying hydraulic characteristics. In the lower Pascagoula River Basin, a drainage area of about 9,500 square miles in Mississippi, riverine and tidal-affected river reaches exist that exhibit fairly steady flows during and after rainfall runoff events, and unsteady flows during low flow, tidal-affected events. Fairly steady flows can be computed usually within 5 percent by using methods developed by the USGS. Accurate measurement and computation of varied, non-uniform open-channel hydraulic streamflow conditions have historically been difficult or impossible. Acoustic and conventional methodologies to measure velocity in an open-channel riverine and tidal-affected reach have been combined to compute continuous discharge during varied, nonuniform flows by using the relations of stage and area in concert with average velocity and index velocity. Due to the unique flow characteristics on the lower Pascagoula River in Mississippi, an independent means of computing high flows based on conventional methods of a log regression of stage and discharge for a range of stages was also used. The two methods were contrasted and had good correlation. Copyright ASCE 2004.

  1. Non-Darcy flow of water through woodchip media

    NASA Astrophysics Data System (ADS)

    Ghane, Ehsan; Fausey, Norman R.; Brown, Larry C.

    2014-11-01

    A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is used to reduce nitrate concentration in water flow. For many years, water flow through woodchips has been assumed laminar without proper validation. The main objective of this study was to validate Darcy's laminar flow assumption for woodchips. For this purpose, we conducted both constant head laboratory column experiments and field evaluation of a denitrification bed. Laboratory results revealed that Darcy's law does not apply for the majority of the hydraulic gradients forcing flow through fresh and old woodchip media. However, Forchheimer's equation adequately described the flow pattern using a quadratic equation. Statistical analysis showed that old woodchips (excavated from a denitrification bed) had significantly lower intrinsic permeability than fresh woodchips. We determined Forchheimer's and Darcy's in-situ coefficients, and used them to predict flow rate in a denitrification bed. Model evaluation statistics showed better flow rate prediction with Forchheimer's than Darcy's equation when compared with the measured flow rate. In conclusion, the linear flow assumption was inadequate for describing water flow through woodchips in a denitrification bed.

  2. Experimental evaluation of factors affecting temporal variability of water samples obtained from long-screened wells

    USGS Publications Warehouse

    Reilly, T.E.; LeBlanc, D.R.

    1998-01-01

    As a well is pumped through time, concentrations of specific constituents in the water discharging from the well may change as a result of their transport within the well and the aquifer. A series of experiments conducted at a research site on Cape Cod, Massachusetts, examined the effects of transport on the chemistry of water samples obtained from a long-screened well. Analyses of time series of constituent concentrations in water pumped from the long-screened well showed persistent temporal trends during the first experiment. Iron concentrations decreased over a five-hour test (15 casing volumes), whereas the calcium and magnesium concentrations increased. In contrast, the time series of constituent concentrations of water discharging from the same well showed less change with time during a later experiment. Numerical simulations were undertaken to test the relative importance of several possible factors affecting the temporal variations of these constituents. During the process of quantitatively explaining the changes in concentrations over time observed in the two experiments, different system conceptualizations were used, including (1) flow and transport in the aquifer without wellbore transport, (2) flow and transport in the aquifer with advective flow and transport in the wellbore, and (3) flow and transport in the aquifer with advective flow and transport in the wellbore and a thin layer (skin) of water surrounding the well with constituent concentrations that had been altered by the presence of the well. The conjectured skin of wellbore water, which could have invaded the aquifer because of nearby sampling or dispersion and diffusion near the wellbore, in conjunction with flow and transport in the aquifer and advective transport within the wellbore, produced a reasonable match between the simulated and observed concentrations. The data analysis confirms the known fact that long-screened wells provide mechanisms for the redistribution of chemical

  3. Influence of surfactants on unsaturated water flow and solute transport

    NASA Astrophysics Data System (ADS)

    Karagunduz, Ahmet; Young, Michael H.; Pennell, Kurt D.

    2015-04-01

    Surfactants can reduce soil water retention by changing the surface tension of water and the contact angle between the liquid and solid phases. As a result, water flow and solute transport in unsaturated soil may be altered in the presence of surfactants. In this study, the effects of a representative nonionic surfactant, Triton X-100, on coupled water flow and nonreactive solute transport during unsaturated flow conditions were evaluated. Batch reactor experiments were conducted to measure the surfactant sorption characteristics, while unsaturated transport experiments were performed in columns packed with 40-270 mesh Ottawa sand at five initial water contents. Following the introduction of surfactant solution, the rate of water percolation through the sand increased; however, this period of rapid water drainage was followed by decreased water percolation due to the reduction in soil water content and the corresponding decrease in unsaturated hydraulic conductivity behind the surfactant front. The observed changes in water percolation occurred sequentially, and resulted in faster nonreactive solute transport than was observed in the absence of surfactant. A one-dimensional mathematical model accurately described coupled water flow, surfactant, and solute transport under most experimental conditions. Differences between model predictions and experimental data were observed in the column study performed at the lowest water content (0.115 cm3/cm3), which was attributed to surfactant adsorption at the air-water interface. These findings demonstrate the potential influence of surfactants additives on unsaturated water flow and solute transport in soils, and demonstrate a methodology to couple these processes in a predictive modeling tool.

  4. Heat transfer research on supercritical water flow upward in tube

    SciTech Connect

    Li, H. B.; Yang, J.; Gu, H. Y.; Zhao, M.; Lu, D. H.; Zhang, J. M.; Wang, F.; Zhang, Y.

    2012-07-01

    The experimental research of heat transfer on supercritical water has been carried out on the supercritical water multipurpose test loop with a 7.6 mm upright tube. The experimental data of heat transfer is obtained. The experimental results of thermal-hydraulic parameters on flow and heat transfer of supercritical water show that: Heat transfer enhancement occurs when the fluid temperature reaches pseudo-critical point with low mass flow velocity, and peters out when the mass flow velocity increases. The heat transfer coefficient and Nusselt number decrease with the heat flux or system pressure increases, and increase with the increasing of mass flow velocity. The wall temperature increases when the mass flow velocity decreases or the system pressure increases. (authors)

  5. WESTERN WATER LAWS AND IRRIGATION RETURN FLOW

    EPA Science Inventory

    The impact of water law allocation and use of waters within the Western United States is currently recognized as one of the major constraints to adaptation by irrigated agriculture of more efficient operation practices. This project provides a background of the law and evaluation...

  6. Use of thermoelectric generator for water flow metering

    NASA Astrophysics Data System (ADS)

    Alothman, Abdulmohsen A.; Zakaria, Mohamed Y.; Hajj, Muhammad R.; Masri, Sami F.

    2016-07-01

    We propose using a thermoelectric generator as a flow meter without requiring additional components. We do so by relating the power generated from the flow of hot water in a pipe to the flow rate. The results show that the steady state values of the power and voltage are more or less independent of the flow rate. On the other hand, the peak power varies significantly with the flow rate. As such, we develop through data analysis a relation between the nondimensional harvested peak power and the Reynolds number. Different sets of experiments are performed to assess the dependence of the developed relation on the boundary conditions. An equation governing this relation is obtained. The proposed approach provides a self-powered monitoring device for quantifying flow rates in pipes conveying hot water.

  7. 5. GORGE HIGH DAM; LOOKING TOWARD INTAKE WITH WATER FLOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GORGE HIGH DAM; LOOKING TOWARD INTAKE WITH WATER FLOWING OVER THE TOP OF THE SPILLGATE, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  8. 6. DETAIL INTAKE NEWHALEM WITH NO WATER FLOWING OVER THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL INTAKE NEWHALEM WITH NO WATER FLOWING OVER THE DAM, 1989. - Skagit Power Development, Newhalem Powerhouse & Dam, On Skagit River, 0.3 mile downstream from Newhalem, Newhalem, Whatcom County, WA

  9. Flame Deflector Section, Elevation, Water Supply Flow Diagram, Exploded ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Flame Deflector - Section, Elevation, Water Supply Flow Diagram, Exploded Deflector Manifolds, and Interior Perspective - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  10. "No. 190. Grand Valley Diversion Dam. Diversion gates, water flowing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "No. 190. Grand Valley Diversion Dam. Diversion gates, water flowing into high line. June, 1917. R.B.D." - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

  11. 2. East side of lower dam shown with water flowing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. East side of lower dam shown with water flowing over dam. VIEW WEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  12. Effect of interfacial layer on water flow in nanochannels: Lattice Boltzmann simulations

    NASA Astrophysics Data System (ADS)

    Jin, Yakang; Liu, Xuefeng; Liu, Zilong; Lu, Shuangfang; Xue, Qingzhong

    2016-04-01

    A novel interfacial model was proposed to understand water flow mechanism in nanochannels. Based on our pore-throat nanochannel model, the effect of interfacial layer on water flow in nanochannels was quantitatively studied using Lattice Boltzmann method (LBM). It is found that both the permeability of nanochannel and water velocity in the nanochannel dramatically decrease with increasing the thickness of interfacial layer. The permeability of nanochannel with pore radius of 10 nm decreases by about three orders of magnitude when the thickness of interfacial layer is changed from 0 nm to 3 nm gradually. Furthermore, it has been demonstrated that the cross-section shape has a great effect on the water flow inside nanochannel and the effect of interfacial layer on the permeability of nanochannel has a close relationship with cross-section shape when the pore size is smaller than 12 nm. Besides, both pore-throat ratio and throat length can greatly affect water flow in nanochannels, and the influence of interfacial layer on water flow in nanochannels becomes more evident with increasing pore-throat ratio and throat length. Our theoretical results provide a simple and effective method to study the flow phenomena in nano-porous media, particularly to quantitatively study the interfacial layer effect in nano-porous media.

  13. 43 CFR 404.57 - Does this rule have any affect on state water law?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... water law? 404.57 Section 404.57 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... this rule have any affect on state water law? No. Neither the Act nor this rule preempts or affects state water law or any interstate compact governing water. Reclamation will comply with state water...

  14. 43 CFR 404.57 - Does this rule have any affect on state water law?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... water law? 404.57 Section 404.57 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... this rule have any affect on state water law? No. Neither the Act nor this rule preempts or affects state water law or any interstate compact governing water. Reclamation will comply with state water...

  15. 43 CFR 404.57 - Does this rule have any affect on state water law?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... water law? 404.57 Section 404.57 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF... this rule have any affect on state water law? No. Neither the Act nor this rule preempts or affects state water law or any interstate compact governing water. Reclamation will comply with state water...

  16. Subsurface And Surface Water Flow Interactions

    EPA Science Inventory

    In this chapter we present basic concepts and principles underlying the phenomena of groundwater and surface water interactions. Fundamental equations and analytical and numerical solutions describing stream-aquifer interactions are presented in hillslope and riparian aquifer en...

  17. Biosolids applications affect runoff water quality following forest fire.

    PubMed

    Meyer, V F; Redente, E F; Barbarick, K A; Brobst, R

    2001-01-01

    Soil erosion and nutrient losses are great concerns following forest wildfires. Biosolids application might enhance revegetation efforts while reducing soil erodibility. Consequently, we applied Denver Metro Wastewater District composted biosolids at rates of 0, 40, and 80 Mg ha(-1) to a severely burned, previously forested site near Buffalo Creek, CO to increase plant cover and growth. Soils were classified as Ustorthents, Ustochrepts, and Haploborols. Simulated rainfall was applied for 30 min at a rate of 100 mm h(-1) to 3- x 10-m paired plots. Biosolids application rates did not significantly affect mean total runoff (p < 0.05). Sediment concentrations were significantly greater (p < 0.05) from the control plots compared with the plots that had received the 80 Mg biosolids ha(-1) rate. Biosolids application rate had mixed effects on water-quality constituents; however, concentrations of all runoff constituents for all treatment rates were below levels recommended for drinking water standards, except Pb. Biosolids application to this site increased plant cover, which should provide erosion control. PMID:11577857

  18. A water tunnel flow visualization study of the vortex flow structures on the F/A-18 aircraft

    NASA Technical Reports Server (NTRS)

    Sandlin, Doral R.; Ramirez, Edgar J.

    1991-01-01

    The vortex flow structures occurring on the F/A-18 aircraft at high angles of attack were studied. A water tunnel was used to gather flow visualization data on the forebody vortex and the wing leading edge extension vortex. The longitudinal location of breakdown of the leading edge vortex was found to be consistently dependent on the angle of attack. Other parameters such as Reynolds number, model scale, and model fidelity had little influence on the overall behavior of the flow structures studied. The lateral location of the forebody vortex system was greatly influenced by changes in the angle of sideslip. Strong interactions can occur between the leading edge extension vortex and the forebody vortex. Close attention was paid to vortex induced flows on various airframe components of the F/A-18. Reynolds number and angle of attack greatly affected the swirling intensity, and therefore the strength of the studied vortices. Water tunnel results on the F/A-18 correlated well with those obtained in similar studies at both full and sub scale levels. The water tunnel can provide, under certain conditions, good simulations of realistic flows in full scale configurations.

  19. Design and implementation of CUAHSI WaterML and WaterOneFlow Web Services

    NASA Astrophysics Data System (ADS)

    Valentine, D. W.; Zaslavsky, I.; Whitenack, T.; Maidment, D.

    2007-12-01

    WaterOneFlow is a term for a group of web services created by and for the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) community. CUAHSI web services facilitate the retrieval of hydrologic observations information from online data sources using the SOAP protocol. CUAHSI Water Markup Language (below referred to as WaterML) is an XML schema defining the format of messages returned by the WaterOneFlow web services. \

  20. The importance of base flow in sustaining surface water flow in the Upper Colorado River Basin

    NASA Astrophysics Data System (ADS)

    Miller, Matthew P.; Buto, Susan G.; Susong, David D.; Rumsey, Christine A.

    2016-05-01

    The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand and the growing recognition that base flow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day base flow across large regions. We adapted and applied the spatially referenced regression on watershed attributes (SPARROW) water quality model to assess the spatial distribution of base flow, the fraction of streamflow supported by base flow, and estimates of and potential processes contributing to the amount of base flow that is lost during in-stream transport in the Upper Colorado River Basin (UCRB). On average, 56% of the streamflow in the UCRB originated as base flow, and precipitation was identified as the dominant driver of spatial variability in base flow at the scale of the UCRB, with the majority of base flow discharge to streams occurring in upper elevation watersheds. The model estimates an average of 1.8 × 1010 m3/yr of base flow in the UCRB; greater than 80% of which is lost during in-stream transport to the Lower Colorado River Basin via processes including evapotranspiration and water diversion for irrigation. Our results indicate that surface waters in the Colorado River Basin are dependent on base flow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin.

  1. E. coli transport to stream water column from bottom sediments to the stream water column in base flow conditions

    NASA Astrophysics Data System (ADS)

    Pachepsky, Yakov; Shelton, Daniel; Stocker, Matthew

    2016-04-01

    E. coli as an indicator bacterium is commonly used to characterize microbiological water quality, to evaluate surface water sources for microbiological impairment, and to assess management practices that lead to the decrease of pathogens and indicator influx in surface water sources for recreation and irrigation. Bottom sediments present a large reservoir of fecal indicator bacteria that are known to be released to water column during high flow events caused by rainstorms and snowmelt. The objective of this work was to see if the influx of E. coli from sediments to water occurs also during base flow periods when groundwater rather than runoff provides the major water input to the stream. The experiment was carried out at the first-order creek in Maryland flowing in the riparian zone in base flow conditions. An inert tracer was released to creek water from the manifold for 5 hours. Streamflow and concentrations of E. coli and tracer were monitored in water 10 m below tracer release location, and at the downstream location at 450 m from the release location. The tracer mass recovered at the downstream location was close to the released tracer mass. We then could directly compare the total numbers of E. coli in volumes of water containing tracer at the upstream (release) location and the downstream location. There was a substantial (3 to 6 times) increase in flow between the upstream and downstream locations as well as the substantial increase in the E. coli total numbers in water (14 to 26 times). The average E. coli influx from the bottom sediment was about 400 cells m-2s-1. Although this value is about 2 to 5 times less than published E. coli release rates during high flow events, it still can substantially change the microbial water quality assessment without any input from animal agriculture or manure application. Interesting research objectives include finding out whether the transport of E. coli from bottom sediment to water column during the base flow periods

  2. Water quality and processes affecting dissolved oxygen concentrations in the Blackwater River, Canaan Valley, West Virginia

    USGS Publications Warehouse

    Waldron, M.C.; Wiley, J.B.

    1996-01-01

    The water quality and environmental processes affecting dissolved oxygen were determined for the Blackwater River in Canaan Valley, West Virginia. Canaan Valley is oval-shaped (14 miles by 5 miles) and is located in the Allegheny Mountains at an average elevation of 3,200 feet above sea level. Tourism, population, and real estate development have increased in the past two decades. Most streams in Canaan Valley are a dilute calcium magnesium bicarbonate-type water. Streamwater typicaly was soft and low in alkalinity and dissolved solids. Maximum values for specific conductance, hardness, alkalinity, and dissolved solids occurred during low-flow periods when streamflow was at or near baseflow. Dissolved oxygen concentrations are most sensitive to processes affecting the rate of reaeration. The reaeration is affected by solubility (atmospheric pressure, water temperature, humidity, and cloud cover) and processes that determine stream turbulence (stream depth, width, velocity, and roughness). In the headwaters, photosynthetic dissolved oxygen production by benthic algae can result in supersaturated dissolved oxygen concentrations. In beaver pools, dissolved oxygen consumption from sediment oxygen demand and carbonaceous biochemical oxygen demand can result in dissolved oxygen deficits.

  3. Does the choice of the forcing term affect flow statistics in DNS of turbulent channel flow?

    NASA Astrophysics Data System (ADS)

    Quadrio, Maurizio; Frohnapfel, Bettina; Hasegawa, Yosuke

    2016-01-01

    We seek possible statistical consequences of the way a forcing term is added to the Navier--Stokes equations in the Direct Numerical Simulation (DNS) of incompressible channel flow. Simulations driven by constant flow rate, constant pressure gradient and constant power input are used to build large databases, and in particular to store the complete temporal trace of the wall-shear stress for later analysis. As these approaches correspond to different dynamical systems, it can in principle be envisaged that these differences are reflect by certain statistics of the turbulent flow field. The instantaneous realizations of the flow in the various simulations are obviously different, but, as expected, the usual one-point, one-time statistics do not show any appreciable difference. However, the PDF for the fluctuations of the streamwise component of wall friction reveals that the simulation with constant flow rate presents lower probabilities for extreme events of large positive friction. The low probability value of such events explains their negligible contribution to the commonly computed statistics; however, the very existence of a difference in the PDF demonstrates that the forcing term is not entirely uninfluential. Other statistics for wall-based quantities (the two components of friction and pressure) are examined; in particular spatio-temporal autocorrelations show small differences at large temporal separations, where unfortunately the residual statistical uncertainty is still of the same order of the observed difference. Hence we suggest that the specific choice of the forcing term does not produce important statistical consequences, unless one is interested in the strongest events of high wall friction, that are underestimated by a simulation run at constant flow rate.

  4. Computing nonhydrostatic shallow-water flow over steep terrain

    USGS Publications Warehouse

    Denlinger, R.P.; O'Connell, D. R. H.

    2008-01-01

    Flood and dambreak hazards are not limited to moderate terrain, yet most shallow-water models assume that flow occurs over gentle slopes. Shallow-water flow over rugged or steep terrain often generates significant nonhydrostatic pressures, violating the assumption of hydrostatic pressure made in most shallow-water codes. In this paper, we adapt a previously published nonhydrostatic granular flow model to simulate shallow-water flow, and we solve conservation equations using a finite volume approach and an Harten, Lax, Van Leer, and Einfeldt approximate Riemann solver that is modified for a sloping bed and transient wetting and drying conditions. To simulate bed friction, we use the law of the wall. We test the model by comparison with an analytical solution and with results of experiments in flumes that have steep (31??) or shallow (0.3??) slopes. The law of the wall provides an accurate prediction of the effect of bed roughness on mean flow velocity over two orders of magnitude of bed roughness. Our nonhydrostatic, law-of-the-wall flow simulation accurately reproduces flume measurements of front propagation speed, flow depth, and bed-shear stress for conditions of large bed roughness. ?? 2008 ASCE.

  5. Launch Environment Water Flow Simulations Using Smoothed Particle Hydrodynamics

    NASA Technical Reports Server (NTRS)

    Vu, Bruce T.; Berg, Jared J.; Harris, Michael F.; Crespo, Alejandro C.

    2015-01-01

    This paper describes the use of Smoothed Particle Hydrodynamics (SPH) to simulate the water flow from the rainbird nozzle system used in the sound suppression system during pad abort and nominal launch. The simulations help determine if water from rainbird nozzles will impinge on the rocket nozzles and other sensitive ground support elements.

  6. Non-Darcy flow of water through woodchip media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A denitrifying bioreactor is a system where a carbon substrate (commonly woodchips) is used to reduce nitrate concentration in water flow. Knowledge of intrinsic permeability of woodchip media in different types of this system is of great importance for design and modeling. For many years, water flo...

  7. Slip ratio in dispersed viscous oil-water pipe flow

    SciTech Connect

    Rodriguez, Iara H.; Yamaguti, Henrique K.B.; de Castro, Marcelo S.; Rodriguez, Oscar M.H.; Da Silva, Marco J.

    2011-01-15

    In this article, dispersed flow of viscous oil and water is investigated. The experimental work was performed in a 26.2-mm-i.d. 12-m-long horizontal glass pipe using water and oil (viscosity of 100 mPa s and density of 860 kg/m{sup 3}) as test fluids. High-speed video recording and a new wire-mesh sensor based on capacitance (permittivity) measurements were used to characterize the flow. Furthermore, holdup data were obtained using quick-closing-valves technique (QCV). An interesting finding was the oil-water slip ratio greater than one for dispersed flow at high Reynolds number. Chordal phase fraction distribution diagrams and images of the holdup distribution over the pipe cross-section obtained via wire-mesh sensor indicated a significant amount of water near to the pipe wall for the three different dispersed flow patterns identified in this study: oil-in-water homogeneous dispersion (o/w H), oil-in-water non-homogeneous dispersion (o/w NH) and Dual continuous (Do/w and Dw/o). The phase slip might be explained by the existence of a water film surrounding the homogeneous mixture of oil-in-water in a hidrofilic-oilfobic pipe. (author)

  8. Water tunnel flow visualisation of vortex breakdown over the F/A-18

    NASA Astrophysics Data System (ADS)

    Thompson, D. H.

    1990-12-01

    Vortex flow patterns over models of the F/A-18 aircraft were visualized using dye and hydrogen bubble techniques in a water tunnel. The axial position of vortex breakdown in the leading-edge extension (LEX) vortices was measured, and was found to be insensitive to Reynolds number, to flap setting, and to small variations in model cross-section shape. Engine inlet flow did alter the vortex breakdown position, at flow rates that might be encountered under flight conditions. The fitting of fences on the LEX upper surface did not affect the axial position of vortex breakdown, but did alter the vortex structure. These alterations were examined in some detail.

  9. Instability of water-ice interface under turbulent flow

    NASA Astrophysics Data System (ADS)

    Izumi, Norihiro; Naito, Kensuke; Yokokawa, Miwa

    2015-04-01

    It is known that plane water-ice interface becomes unstable to evolve into a train of waves. The underside of ice formed on the water surface of rivers are often observed to be covered with ice ripples. Relatively steep channels which discharge melting water from glaciers are characterized by beds covered with a series of steps. Though the flowing agent inducing instability is not water but gas including water vapor, a similar train of steps have been recently observed on the Polar Ice Caps on Mars (Spiral Troughs). They are expected to be caused by the instability of water-ice interface induced by flowing fluid on ice. There have been some studies on this instability in terms of linear stability analysis. Recently, Caporeale and Ridolfi (2012) have proposed a complete linear stability analysis in the case of laminar flow, and found that plane water-ice interface is unstable in the range of sufficiently large Reynolds numbers, and that the important parameters are the Reynolds number, the slope angle, and the water surface temperature. However, the flow inducing instability on water-ice interface in the field should be in the turbulent regime. Extension of the analysis to the case of fully developed turbulent flow with larger Reynolds numbers is needed. We have performed a linear stability analysis on the instability of water-ice interface under turbulent flow conditions with the use of the Reynolds-averaged Navier-Stokes equations with the mixing length turbulent model, the continuity equation of flow, the diffusion/dispersion equation of heat, and the Stefan equation. In order to reproduce the accurate velocity distribution and the heat transfer in the vicinity of smooth walls with the use of the mixing length model, it is important to take into account of the rapid decrease in the mixing length in the viscous sublayer. We employ the Driest model (1956) to the formulation. In addition, as the thermal boundary condition at the water surface, we describe the

  10. One-Water Hydrologic Flow Model (MODFLOW-OWHM)

    USGS Publications Warehouse

    Hanson, Randall T.; Boyce, Scott E.; Schmid, Wolfgang; Hughes, Joseph D.; Mehl, Steffen W.; Leake, Stanley A.; Maddock, Thomas, III; Niswonger, Richard G.

    2014-01-01

    The One-Water Hydrologic Flow Model (MF-OWHM) is a MODFLOW-based integrated hydrologic flow model (IHM) that is the most complete version, to date, of the MODFLOW family of hydrologic simulators needed for the analysis of a broad range of conjunctive-use issues. Conjunctive use is the combined use of groundwater and surface water. MF-OWHM allows the simulation, analysis, and management of nearly all components of human and natural water movement and use in a physically-based supply-and-demand framework. MF-OWHM is based on the Farm Process for MODFLOW-2005 (MF-FMP2) combined with Local Grid Refinement (LGR) for embedded models to allow use of the Farm Process (FMP) and Streamflow Routing (SFR) within embedded grids. MF-OWHM also includes new features such as the Surface-water Routing Process (SWR), Seawater Intrusion (SWI), and Riparian Evapotrasnpiration (RIP-ET), and new solvers such as Newton-Raphson (NWT) and nonlinear preconditioned conjugate gradient (PCGN). This IHM also includes new connectivities to expand the linkages for deformation-, flow-, and head-dependent flows. Deformation-dependent flows are simulated through the optional linkage to simulated land subsidence with a vertically deforming mesh. Flow-dependent flows now include linkages between the new SWR with SFR and FMP, as well as connectivity with embedded models for SFR and FMP through LGR. Head-dependent flows now include a modified Hydrologic Flow Barrier Package (HFB) that allows optional transient HFB capabilities, and the flow between any two layers that are adjacent along a depositional or erosional boundary or displaced along a fault. MF-OWHM represents a complete operational hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for consumption by irrigated agriculture, but also of water used in urban areas and by natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply

  11. Temporal evolution of water repellency and preferential flow in the post-fire

    NASA Astrophysics Data System (ADS)

    Alanís, Nancy; Jordán, Antonio; Zavala, Lorena M.

    2015-04-01

    Forest fires usually intensify erosive process due to the reduction of vegetation cover and degradation of aggregation in the topsoil. Another common effect of wildifres is the development of soil water repellency, which in turn favors the formation of runoff, inhibiting or delaying infiltration. Under these conditions, infiltration occurs only when ponded water or runoff flow finds macropores and cracks in the soil surface, producing preferential flow pathways. When water infiltrates through these paths, a significant portion of the soil remains dry, limiting the supply of nutrients to the roots, favoring the rapid leaching of nutrients and agrochemicals, and other impacts on flora and hydrological processes at hillslope- or basin-scale. The existence of irregular wetting fronts has been observed frequently in burned or unburned water repellent soils. Although some authors have suggested that preferential flow paths may be more or less permanent in the case of unburned soils, the temporal evolution of preferential flow has been rarely studied in burned soils during the post-fire, after water repellency decreases or disappears. This research focuses on the temporal evolution of water repellency and preferential flows in an area affected by fire.

  12. Water Flow Investigation on Quartz Sand with 13-interval Stimulated Echo Multi Slice Imaging

    NASA Astrophysics Data System (ADS)

    Spindler, Natascha; Pohlmeier, Andreas; Galvosas, Petrik

    2011-03-01

    Understanding root water uptake in soils is of high importance for securing nutrition in the context of climate change and linked phenomena like stronger varying weather conditions (draught, strong rain). One step to understand how root water uptake occurs is the knowledge of the water flow in soil towards plant roots. Magnetic Resonance Imaging (MRI) in combination with q-space imaging is potentially the most powerful analytical tool for non-invasive three dimensional visualization of flow and transport in porous media. Numerous attempts have been made to measure local velocity in porous media by combining velocity phase encoding with fast imaging methods, where flow velocities in the vascular bundles of plant stems were investigated. In contrast to water situated in the cellular structure of plants, NMR signal arising from water in the pore space in soil may be much more affected by the presence of internal magnetic field gradients. In this work we account for the existence of these gradients by employing bipolar pulsed field magnetic gradients for velocity encoding. This enables one to study flow through sand (as a model system for soil) at flow rates relevant for the water uptake of plant roots.

  13. Factors affecting ground-water exchange and catchment size for Florida lakes in mantled karst terrain

    USGS Publications Warehouse

    Lee, Terrie Mackin

    2002-01-01

    In the mantled karst terrain of Florida, the size of the catchment delivering ground-water inflow to lakes is often considerably smaller than the topographically defined drainage basin. The size is determined by a balance of factors that act individually to enhance or diminish the hydraulic connection between the lake and the adjacent surficial aquifer, as well as the hydraulic connection between the surficial aquifer and the deeper limestone aquifer. Factors affecting ground-water exchange and the size of the ground-water catchment for lakes in mantled karst terrain were examined by: (1) reviewing the physical and hydrogeological characteristics of 14 Florida lake basins with available ground-water inflow estimates, and (2) simulating ground-water flow in hypothetical lake basins. Variably-saturated flow modeling was used to simulate a range of physical and hydrogeologic factors observed at the 14 lake basins. These factors included: recharge rate to the surficial aquifer, thickness of the unsaturated zone, size of the topographically defined basin, depth of the lake, thickness of the surficial aquifer, hydraulic conductivity of the geologic units, the location and size of karst subsidence features beneath and onshore of the lake, and the head in the Upper Floridan aquifer. Catchment size and the magnitude of ground-water inflow increased with increases in recharge rate to the surficial aquifer, the size of the topographically defined basin, hydraulic conductivity in the surficial aquifer, the degree of confinement of the deeper Upper Floridan aquifer, and the head in the Upper Floridan aquifer. The catchment size and magnitude of ground-water inflow increased with decreases in the number and size of karst subsidence features in the basin, and the thickness of the unsaturated zone near the lake. Model results, although qualitative, provided insights into: (1) the types of lake basins in mantled karst terrain that have the potential to generate small and large

  14. Canopy temperature view angle affects on the water deficit index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased water use efficiency for irrigated agricultural crop production requires solutions that improve irrigation scheduling and management. Several techniques exist that utilize canopy temperature measurements to assess the severity of plant water stress. The Water Deficit Index (WDI) was develo...

  15. Actuation of interfacial waves in oil-water flows

    NASA Astrophysics Data System (ADS)

    Park, Kyeong; Weheliye, Weheliye; Chinaud, Maxime; Angeli, Panagiota; James Percival Collaboration; Omar. K. Matar Collaboration

    2015-11-01

    Droplet detachment from interfacial waves in two-phase flows has pulled in noteworthy exploration interest. In order to examine this phenomenon experimentally and empower quantitative estimation, it is important to spatially confine the drop formation. In the present study, a cylinder, located close to the inlet of the test section and perpendicular to the direction of the flow, is placed in a two-phase stratified oil-water pipe flow. The introduction of this cylinder actuated interfacial waves and move from stratified to dispersed flow pattern. High speed visualisation and Particle Image Velocimetry (PIV) measurement are utilized to investigate the flow pattern maps of the two-phase flow and the velocity fields in the wake of the cylinder, respectively. These results will be compared with previous experimental studies. Department of Chemical Engineering South Kensington Campus Imperial College London SW7 2AZ.

  16. Factors affecting measurement of channel thickness in asymmetrical flow field-flow fractionation.

    PubMed

    Dou, Haiyang; Jung, Euo Chang; Lee, Seungho

    2015-05-01

    Asymmetrical flow field-flow fractionation (AF4) has been considered to be a useful tool for simultaneous separation and characterization of polydisperse macromolecules or colloidal nanoparticles. AF4 analysis requires the knowledge of the channel thickness (w), which is usually measured by injecting a standard with known diffusion coefficient (D) or hydrodynamic diameter (dh). An accurate w determination is a challenge due to its uncertainties arising from the membrane's compressibility, which may vary with experimental condition. In the present study, influence of factors including the size and type of the standard on the measurement of w was systematically investigated. The results revealed that steric effect and the particles-membrane interaction by van der Waals or electrostatic force may result in an error in w measurement. PMID:25817708

  17. Land cover change and water vapour flows: learning from Australia.

    PubMed Central

    Gordon, Line; Dunlop, Michael; Foran, Barney

    2003-01-01

    Australia is faced with large-scale dryland salinization problems, largely as a consequence of the clearing of native vegetation for cropland and grassland. We estimate the change in continental water vapour flow (evapotranspiration) of Australia during the past 200 years. During this period there has been a substantial decrease in woody vegetation and a corresponding increase in croplands and grasslands. The shift in land use has caused a ca. 10% decrease in water vapour flows from the continent. This reduction corresponds to an annual freshwater flow of almost 340 km(3). The society-induced alteration of freshwater flows is estimated at more than 15 times the volume of run-off freshwater that is diverted and actively managed in the Australian society. These substantial water vapour flow alterations were previously not addressed in water management but are now causing serious impacts on the Australian society and local economies. Global and continental freshwater assessments and policy often neglects the interplay between freshwater flows and landscape dynamics. Freshwater issues on both regional and global levels must be rethought and the interplay between terrestrial ecosystems and freshwater better incorporated in freshwater and ecosystem management. PMID:14728792

  18. A water tunnel flow visualization study of the F-15

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1978-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-15 aircraft. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Particular emphasis was placed on defining vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop diagnostic water tunnel using a 1/48-scale model of the F-15. Flow visualization pictures were obtained over an angle-of-attack range to 55 deg and sideslip angles up to 10 deg. The basic aircraft configuration was investigated in detail to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Additional tests showed that the wing upper surface vortex flow fields were sensitive to variations in inlet mass flow ratio and inlet cowl deflection angle. Asymmetries in the vortex systems generated by each of the three forebodies were observed in the water tunnel at zero sideslip and high angles of attack.

  19. Site assessors take note: Water doesn`t always flow downhill

    SciTech Connect

    Shuey, R.W. |

    1996-05-01

    With increasing frequency, geologists are being called as expert witnesses to testify in court that water does not necessarily flow downhill--a fact that has been overlooked by the environmental consulting industry. Environmental site assessments that are performed quickly by unqualified people and within the bounds of very tight budgets are inaccurate because contaminated groundwater from downgradient sites is showing up in upgradient wells. Much of the litigation involving groundwater contamination revolves around the fact that groundwater environments vary--water can behave differently in one environment than it does in another. The regional environment considers the characteristics of groundwater movement in a geologic environment encompassing many square miles, whereas the local or site-specific environment may involve only a single property. Although groundwater at a regional level tends to flow in the direction of the slope of regional topography, many surface and subsurface characteristics will affect the direction of groundwater flow before it reaches the water table.

  20. Flow analysis on sea-water mists flows among bridge beams

    NASA Astrophysics Data System (ADS)

    Ishikawa, Masaaki; Oshiro, Daigo

    2014-04-01

    In the subtropical islands enclosed in the ocean, there is a problem that corrosion of structures progresses quickly because of high temperature and humidity and adhesion of sea-water mists flying from sea. Authors are interested in corrosion of bridge made of weatherability steel. Therefore, it needs to investigate the flow structure around bridge beams and motion of sea-water mist (droplet). In this paper, authors attempt flow visualization and PIV to understand the flow structures around bridge beams and numerical approach of motion of droplets to understand the collision of seawater mists on the bridge wall.

  1. An initial inverse calibration of the ground-water flow model for the Hanford unconfined aquifer

    SciTech Connect

    Jacobson, E.A. . Desert Research Inst.); Freshly, M.D. )

    1990-03-01

    Large volumes of process cooling water are discharged to the ground form U.S. Department of Energy (DOE) nuclear fuel processing operations in the central portion of the Hanford Site in southeastern Washington. Over the years, these large volumes of waste water have recharged the unconfined aquifer at the Site. This artificial recharge has affected ground-water levels and contaminant movement in the unconfined aquifer. Ground-water flow and contaminant transport models have been applied to assess the impacts of site operations on the rate and direction of ground-water flow and contaminant transport in unconfined aquifer at the Hanford Site. The inverse calibration method developed by Neuman and modified by Jacobson was applied to improve calibration of a ground-water flow model of the unconfined aquifer at the Hanford Site. All information about estimates of hydraulic properties of the aquifer, hydraulic heads, boundary conditions, and discharges to and withdrawals form the aquifer is included in the inverse method to obtain an initial calibration of the ground-water flow model. The purpose of this report is to provide a description of the inverse method, its initial application to the unconfined aquifer at Hanford, and to present results of the initial inverse calibration. 28 refs., 19 figs., 1 tab.

  2. Ductile flow by water-assisted cataclasis

    NASA Astrophysics Data System (ADS)

    den Brok, Bas

    2003-04-01

    In the presence of water otherwise brittle materials may deform macroscopically ductile by water-assisted cataclastic creep. This is possible as long as (i) solubility is high enough, so that stress-corrosion can occur, and (ii) local stress is low enough, to that fracturing remains subcritical. Water-assisted cataclastic creep (WACC) may play an important role in the middle and lower continental crust where mineral solubilities are high and stresses low. WACC is a poorly understood deformation process. Experiments were performed on very soluble brittle salts (Na-chlorate; K-alum) to study microstructure development by WACC. The experiments were carried out at room temperature and atmospheric pressure in a small see-through vessel. In this way the cataclastic deformation process could be studied "in-situ" under the microscope. Crystals were loaded in the presence of saturated salt solution. It appeared that originally straight mineral surfaces were instable when kept under stress. Grooves (or channels) slowly developed in the surface by local dissolution. These grooves behave like so-called Grinfeld instabilities. They develop because the energy of a grooved surface under stress is lower than the energy of a straight surface under stress. The grooves may deepen and turn into subcritical cracks when local stress further increases. These cracks propagate slowly. They propagate parallel to sigma1 but also at an angle and even perpendicular to sigma1, often following crystallographically controlled directions. The fractures mostly change direction while propagating, locally making turns of more than 180 degrees. Irregular fracture fragments thus develop. The fractures may migrate sideways (as with grain bounday migration) probably by solution-redeposition driven by differences in stress between both sides of the fracture. Thus the shape of the fragments changes. The size of the fracture fragments seems to be controlled by the distance of the grooves, which decreases

  3. Harbor seals (Phoca vitulina) can perceive optic flow under water.

    PubMed

    Gläser, Nele; Mauck, Björn; Kandil, Farid I; Lappe, Markus; Dehnhardt, Guido; Hanke, Frederike D

    2014-01-01

    Optic flow, the pattern of apparent motion elicited on the retina during movement, has been demonstrated to be widely used by animals living in the aerial habitat, whereas underwater optic flow has not been intensively studied so far. However optic flow would also provide aquatic animals with valuable information about their own movement relative to the environment; even under conditions in which vision is generally thought to be drastically impaired, e. g. in turbid waters. Here, we tested underwater optic flow perception for the first time in a semi-aquatic mammal, the harbor seal, by simulating a forward movement on a straight path through a cloud of dots on an underwater projection. The translatory motion pattern expanded radially out of a singular point along the direction of heading, the focus of expansion. We assessed the seal's accuracy in determining the simulated heading in a task, in which the seal had to judge whether a cross superimposed on the flow field was deviating from or congruent with the actual focus of expansion. The seal perceived optic flow and determined deviations from the simulated heading with a threshold of 0.6 deg of visual angle. Optic flow is thus a source of information seals, fish and most likely aquatic species in general may rely on for e. g. controlling locomotion and orientation under water. This leads to the notion that optic flow seems to be a tool universally used by any moving organism possessing eyes. PMID:25058490

  4. Flow field simulation of gas-water two phase flow in annular channel

    NASA Astrophysics Data System (ADS)

    Ji, Pengcheng; Dong, Feng

    2014-04-01

    The gas-water two-phase flow is very common in the industrial processes. the deep understanding of the two-phase flow state is to achieve the production equipment design and safe operation. In the measurement of gas-water two-phase flow, the differential pressure sensor is widely used, and some measurement model of multiphase flow have been concluded. The differential pressure is generated when fluid flowing through the throttling components to calculate flow rate. This paper mainly focuses on two points: 1. The change rule of the parameters include velocity, pressure, phase fraction as the change of time, when the phase inlet velocity is given. 2. Analysis the distribution of the parameters above-mentioned at a certain moment under the condition of different water inlet velocity. Three-dimensional computational fluid dynamics (CFD) approach was used to simulate gas-water two-phase flow fluid in the annular channel, which is composed of horizontal pipe and long- waist cone sensor. The simulation results were obtained from FLUENT software.

  5. Integrating blue and green water flows for water resources management and planning

    NASA Astrophysics Data System (ADS)

    Jewitt, Graham

    The “Green Water” approach, where flows of water vapour in the form of transpiration, interception and evaporation from the soil and vegetation is considered green water and runoff and groundwater recharge is considered blue water, has been an extremely useful illustrative concept in many situations where the role of land use in water resources management needs to be highlighted. The approach has been the subject of much interest in recent years, particularly in semi-arid and arid regions where Green Water Flows dominate the hydrological cycle. However, it is clear that there are limits to the concept in informing water resources management and planning. In this paper, these limits are explored through case studies of commercial afforestation and runoff harvesting in the SADC region. Issues highlighted include the degree of simplification of the hydrological cycle in many green water focused studies, appropriate spatial and temporal scales for the consideration of low flows and the uncertainty regarding the storage of water in the soil profile and the generation of flows from saturated and unsaturated soil water. It is concluded that rather than focusing on green or blue water flows, it is the hydrological linkages between these and their representation in water resources management and planning that needs most attention.

  6. Flow Simulation of Solid Rocket Motors. 1; Injection Induced Water-Flow Tests from Porous Media

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Yeh, Y. P.; Smith, A. W.; Heaman, J. P.

    1999-01-01

    Prior to selecting a proper porous material for use in simulating the internal port flow of a solid rocket motor (SRM), in cold-flow testing, the flow emerging from porous materials is experimentally investigated. The injection-flow emerging from a porous matrix always exhibits a lumpy velocity profile that is spatially stable and affects the development of the longitudinal port flow. This flow instability, termed pseudoturbulence, is an inherent signature of the porous matrix and is found to generally increase with the wall porosity and with the injection flow rate. Visualization studies further show that the flow from porous walls made from shaving-type material (sintered stainless-steel) exhibits strong recirculation zones that are conspicuously absent in walls made from nodular or spherical material (sintered bronze). Detailed flow visualization observations and hot-film measurements are reported from tests of injection-flow and a coupled cross-flow from different porous wall materials. Based on the experimental data, discussion is provided on the choice of suitable material for SRM model testing while addressing the consequences and shortcomings from such a test.

  7. Protein synthesis inhibitors attenuate water flow in vasopressin-stimulated toad urinary bladder

    SciTech Connect

    Hoch, B.S.; Ast, M.B.; Fusco, M.J.; Jacoby, M.; Levine, S.D. )

    1988-01-01

    Vasopressin stimulates the introduction of aggregated particles, which may represent pathways for water flow, into the luminal membrane of toad urinary bladder. It is not known whether water transport pathways are degraded on removal from membrane or whether they are recycled. The authors examined the effect of the protein synthesis inhibitors cycloheximide and puromycin using repeated 30-min cycles of vasopressin followed by washout of vasopressin, all in the presence of an osmotic gradient, a protocol that maximizes aggregate turnover. High dose cycloheximide inhibited flow immediately. Low dose cycloheximide did not affect initial flow. In the absence of vasopressin, inhibition did not develop. Despite the inhibition of flow in vasopressin-treated tissues, the cAMP-dependent protein kinase ratio was elevated in cycloheximide-treated tissues, suggesting modulation at a distal site in the stimulatory cascade. ({sup 14}C)urea permeability was not inhibited by cycloheximide. Puromycin also inhibited water flow by the fourth challenge with vasopressin. The data suggest that protein synthesis inhibitors attenuate flow at a site that is distal to cAMP-dependent protein kinase. However, the reversal of inhibition in MIX-treated tissues suggests that the water pathway can be fully manifested given suitable stimulation. They conclude that either large stores of the transport system are available or that the transport system is extensively recycled on retrieval from the membrane.

  8. Do water-saving technologies improve environmental flows?

    NASA Astrophysics Data System (ADS)

    Batchelor, Charles; Reddy, V. Ratna; Linstead, Conor; Dhar, Murli; Roy, Sumit; May, Rebecca

    2014-10-01

    Water saving and conservation technologies (WCTs) have been promoted widely in India as a practical means of improving the water use efficiency and freeing up water for other uses (e.g. for maintaining environmental flows in river systems). However, there is increasing evidence that, somewhat paradoxically, WCTs often contribute to intensification of water use by irrigated and rainfed farming systems. This occurs when: (1) Increased crop yields are coupled with increased consumptive water use and/or (2) Improved efficiency, productivity and profitability encourages farmers to increase the area cropped and/or to adopt multiple cropping systems. In both cases, the net effect is an increase in annual evapotranspiration that, particularly in areas of increasing water scarcity, can have the trade-off of reduced environmental flows. Recognition is also increasing that the claimed water savings of many WCTs may have been overstated. The root cause of this problem lies in confusion over what constitutes real water saving at the system or basin scales. The simple fact is that some of the water that is claimed to be ‘saved’ by WCTs would have percolated into the groundwater from where it can be and often is accessed and reused. Similarly, some of the “saved” runoff can be used downstream by, for example, farmers or freshwater ecosystems. This paper concludes that, particularly in areas facing increasing water scarcity, environmental flows will only be restored and maintained if they are given explicit (rather than theoretical or notional) attention. With this in mind, a simple methodology is proposed for deciding when and where WCTs may have detrimental impacts on environmental flows.

  9. Water: The Flow of Women's Work. Water in Africa.

    ERIC Educational Resources Information Center

    Cohen, Amy

    The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers, World Wise Schools (WWS) classroom teachers, and WWS staff members. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning…

  10. Ephemeral skin-flows on talus affected by permafrost degradation (Corral del Veleta, Spain)

    NASA Astrophysics Data System (ADS)

    Tanarro, L. M.; Palacios, D.; Zamorano, J. J.; Gómez, A.

    2009-04-01

    temperature (BTS measurements, miniature temperature dataloggers) and geophysical surveys (Gómez et al., 2001, 2003). However, these methods for detecting permafrost (pending more detailed surveys) have shown that the presence of permafrost or buried ice in the slope is discontinuous. The geomorphological interpretation shows that the flows are small scale. The maximum length of the largest flow occurring during the observation period is around 50 m, and its width oscillates between 25-30 m. In general the flow only affects a layer of debris of less than 30 cm. The dislodged layer is made up of fine material and small clasts or gravel and pebble sized fragments, with a significant presence of numerous multiple flows which diverge or divide when they encounter a large block and end up forming small lobes. The interior of these is made up of fine material (clay and silt) and the lobe itself is made of small, tightly compressed fragments. Here it should also be noted that many of the flows are stopped or ended when they collide with a block of larger size, forming a series of lobes. It seems clear that many of these flows, as they are moving only a thin layer of fine material, are controlled by the presence of larger blocks which remain stable on the slope. The location of the skin flows at the base of the snowpatches in late summer seems to be the main factor which triggers their genesis. Here, as has been observed in other areas, the absence of vegetation and the abundant water delivered by the rapid nival fusion or snow melt, stronger here as this is an area with Mediterranean climate and also linked to the presence of abundant fine material, provide the conditions needed to favor the triggering of this kind of movement. However it was observed that some skin flows develop in sectors of the slope where the permafrost is absent and so their origin seems to be clearly related to the snow melt. In addition in these cases, the morphology of the flows once they are formed is not

  11. ESTIMATING FLOW AND FLUX OF GROUND-WATER DISCHARGE USING WATER TEMPERATURE AND VELOCITY. (R827961)

    EPA Science Inventory

    The nature of ground water discharge to a stream has important implications for nearby ground water flow, especially with respect to contaminant transport and well-head protection. Measurements of ground water discharge were accomplished in this study using (1) differences bet...

  12. Alternate conceptual model of ground water flow at Yucca Mountain

    SciTech Connect

    1993-12-31

    Attempts to predict the performance of a high-level nuclear waste repository in the United States have lead to the development of alternative conceptual models of the ground watre flow field in which the repository will be located. This step has come about because of the lage uncertainties involved in predicting the movement of water and radionuclides through an unsaturated fractured rock. Further, one of the standards to which we are comparing performance is probabilistic, so we are forced to try to conceive of all credible scenarios by which ground water may intersect the repository horizon and perhaps transport radionuclides to a given compliance boundary. To simplify this task, the DOE set about identifying alternative conceptual models of ground water flow which are consistent with existing data. Modeling these concepts necessitates the use of simplifying assumptions. Among the modeling assumptions commonly utilized by analysts of the Yucca Mountain site are those of uniformly distributed, small volumes of recharge and matrix or porous media flow. Most scientists would agree that recharge at Yucca Mountain does not occur in this ideal and simplified fashion, yet modeling endeavors continue to commonly utilize this approach. In this paper, we examine the potential effects of focused recharge on the flow field at Yucca Mountain in concert with a fractured matrix and non-equilibrium view of ground water flow.

  13. Microscopic suspension feeders near boundaries: Effects of external water flow

    NASA Astrophysics Data System (ADS)

    Pepper, Rachel; Koehl, M. A. R.

    2015-11-01

    Microscopic sessile suspension feeders are an important part of aquatic ecosystems and form a vital link in the transfer of carbon in aquatic food webs. These suspension feeders live attached to boundaries, consume bacteria and small detritus, and are in turn eaten by larger organisms. Many create a feeding current that draws fluid towards them, and from which they filter their food. In still water, the feeding current consists of recirculating eddies which form as a result of fluid forcing near a boundary. These recirculating eddies can be depleted of food and significantly decrease nutrient uptake; a variety of strategies have been proposed for how attached feeders increase their access to undepleted water. We investigate the interaction of the flow produced by a microscopic suspension feeder with external environmental flow, such as the current in a stream or ocean. We show through calculations that even very slow flow (on the order of microns per second) is sufficient to provide a constant supply of undepleted water to suspension feeders when the feeders are modeled with perfect nutrient capture efficiency and in the absence of diffusion. We also discuss which natural flow environments exceed the threshold to supply undepleted water and which do not, and we examine how characteristics of the suspension feeders themselves, such as stalk length and feeding disk size, influence feeding currents and their interactions with external flows.

  14. Wave-Generated Flows on the Water Surface

    NASA Astrophysics Data System (ADS)

    Shats, Michael; Punzmann, Horst; Francois, Nicolas; Xia, Hua

    2016-06-01

    Predicting trajectories of fluid parcels on the water surface perturbed by waves is a difficult mathematical and theoretical problem. It is even harder to model flows generated on the water surface due to complex three-dimensional wave fields, which commonly result from the modulation instability of planar waves. We have recently shown that quasi-standing, or Faraday, waves are capable of generating horizontal fluid motions on the water surface whose statistical properties are very close to those in two-dimensional turbulence. This occurs due to the generation of horizontal vortices. Here we show that progressing waves generated by a localized source are also capable of creating horizontal vortices. The interaction between such vortices can be controlled and used to create stationary surface flows of desired topology. These results offer new methods of surface flow generation, which allow engineering inward and outward surface jets, large-scale vortices and other complex flows. The new principles can be also be used to manipulate floaters on the water surface and to form well-controlled Lagrangian coherent structures on the surface. The resulting flows are localized in a narrow layer near the surface, whose thickness is less than one wavelength.

  15. Geomorphological evidence for transient water flow on Vesta

    NASA Astrophysics Data System (ADS)

    Scully, Jennifer E. C.; Russell, Christopher T.; Yin, An; Jaumann, Ralf; Carey, Elizabeth; Castillo-Rogez, Julie; McSween, Harry Y.; Raymond, Carol A.; Reddy, Vishnu; Le Corre, Lucille

    2015-02-01

    Vesta, the second most massive asteroid, has long been perceived as anhydrous. Recent studies suggesting the presence of hydrated minerals and past subsurface water have challenged this long-standing perception. Yet, direct geologic indications of water activity on Vesta's surface were unexpected. Herein we show evidence that transient water flowed on the surface, in a debris-flow-like process, and left distinctive geomorphologic features. Based on detailed analysis of highest-resolution (∼20 m/pixel) images obtained by the Dawn spacecraft, we identify a class of locally occurring, interconnected and curvilinear gully networks on the walls of young (< hundreds of Ma) impact craters, ending in lobate deposits near the crater floors. As curvilinear systems only occur within impact craters, we propose that they formed by a particulate-dominated flow of transient water that was released from buried ice-bearing deposits by impact-induced heating and melting. This interpretation is in accordance with the occurrence of pitted terrain on lobate deposits and crater floors. Pitted terrain is proposed to result from the degassing of volatiles. The proposed buried ice-bearing deposits are likely localized in extent and may be currently extant in Vesta's subsurface. Together with the discovery of water evaporation on Ceres and water activity on several small asteroids, our results support the new paradigm that water is widespread in the asteroid belt.

  16. South Asia river flow projections and their implications for water resources

    NASA Astrophysics Data System (ADS)

    Mathison, C.; Wiltshire, A. J.; Falloon, P.; Challinor, A. J.

    2015-06-01

    South Asia is a region with a large and rising population and a high dependance on industries sensitive to water resource such as agriculture. The climate is hugely variable with the region relying on both the Asian Summer Monsoon (ASM) and glaciers for its supply of fresh water. In recent years, changes in the ASM, fears over the rapid retreat of glaciers and the increasing demand for water resources for domestic and industrial use, have caused concern over the reliability of water resources both in the present day and future for this region. The climate of South Asia means it is one of the most irrigated agricultural regions in the world, therefore pressures on water resource affecting the availability of water for irrigation could adversely affect crop yields and therefore food production. In this paper we present the first 25 km resolution regional climate projections of river flow for the South Asia region. ERA-Interim, together with two global climate models (GCMs), which represent the present day processes, particularly the monsoon, reasonably well are downscaled using a regional climate model (RCM) for the periods; 1990-2006 for ERA-Interim and 1960-2100 for the two GCMs. The RCM river flow is routed using a river-routing model to allow analysis of present day and future river flows through comparison with river gauge observations, where available. In this analysis we compare the river flow rate for 12 gauges selected to represent the largest river basins for this region; Ganges, Indus and Brahmaputra basins and characterize the changing conditions from east to west across the Himalayan arc. Observations of precipitation and runoff in this region have large or unknown uncertainties, are short in length or are outside the simulation period, hindering model development and validation designed to improve understanding of the water cycle for this region. In the absence of robust observations for South Asia, a downscaled ERA-Interim RCM simulation provides a

  17. Slip flow coefficient analysis in water hydraulics gear pump for environmental friendly application

    NASA Astrophysics Data System (ADS)

    Yusof, A. A.; Wasbari, F.; Zakaria, M. S.; Ibrahim, M. Q.

    2013-12-01

    Water hydraulics is the sustainable option in developing fluid power systems with environmental friendly approach. Therefore, an investigation on water-based external gear pump application is being conducted, as a low cost solution in the shifting effort of using water, instead of traditional oil hydraulics in fluid power application. As the gear pump is affected by fluid viscosity, an evaluation has been conducted on the slip flow coefficient, in order to understand to what extent the spur gear pump can be used with water-based hydraulic fluid. In this paper, the results of a simulated study of variable-speed fixed displacement gear pump are presented. The slip flow coefficient varies from rotational speed of 250 RPM to 3500 RPM, and provides volumetric efficiency ranges from 9 % to 97% accordingly.

  18. Sculpting of a dissolvable body by flowing water

    NASA Astrophysics Data System (ADS)

    Huang, Jinzi Mac; Moore, M. Nicholas J.; Ristroph, Leif

    2014-11-01

    Fluid flows strongly influence the dissolution of materials in geological contexts and in chemical and pharmaceutical applications. We approach flow-driven dissolution as a moving boundary problem and conduct experiments on hard candy bodies immersed within fast flowing water. We discover that different initial shapes are sculpted into a similar final form before ultimately vanishing, suggesting convergence to a stable shape-flow state. A model linking the flow and solute concentration suggests an explanation for this state and offers scaling laws for quantities such as the volume decay rate in time. As a whimsical application, we also show how this model can be used to address the long-standing question, ``How many licks does it take to get to the center of lollipop?''

  19. Factors Affecting Atrazine Concentration and Quantitative Determination in Chlorinated Water

    EPA Science Inventory

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be obser...

  20. Relative significance of microtopography and vegetation as controls on surface water flow on a low-gradient floodplain

    USGS Publications Warehouse

    Choi, Jungyill; Harvey, Judson W.

    2014-01-01

    Surface water flow controls water velocities, water depths, and residence times, and influences sediment and nutrient transport and other ecological processes in shallow aquatic systems. Flow through wetlands is substantially influenced by drag on vegetation stems but is also affected by microtopography. Our goal was to use microtopography data directly in a widely used wetland model while retaining the advantages of the model’s one-dimensional structure. The base simulation with no explicit treatment of microtopography only performed well for a period of high water when vegetation dominated flow resistance. Extended simulations using microtopography can improve the fit to low-water conditions substantially. The best fit simulation had a flow conductance parameter that decreased in value by 70 % during dry season such that mcrotopographic features blocked 40 % of the cross sectional width for flow. Modeled surface water became ponded and flow ceased when 85 % of the cross sectional width became blocked by microtopographic features. We conclude that vegetation drag dominates wetland flow resistance at higher water levels and microtopography dominates at low water levels with the threshold delineated by the top of microtopographic features. Our results support the practicality of predicting flow on floodplains using relatively easily measured physical and biological variables.

  1. Flow through porous media of packed spheres saturated with water

    SciTech Connect

    Kececioglu, I.; Jiang, Y. . Dept. of Mechanical Engineering)

    1994-03-01

    The existing literature on the flow of fluids through porous packed beds gives very limited quantitative information of the criteria employed in marking the applicability of the different flow regimes. It is the objective of this paper to provide experimental evidence for determining the demarcation criteria during the flow of water through a bed of randomly packed spherical beads. Two different sizes of glass beads, 3 mm and 6 mm, were employed as the porous matrix through which water flowed at rates varying from 5.07 [times] 10[sup [minus]6] m[sup 3]/s to 4,920 [times] 10[sup [minus]6] m[sup 3]/s. The dimensionless pressure drop data showed less variation when the characteristic length of the porous medium was taken to be proportional to the square root of the permeability over the porosity and not the bead diameter. Curves of properly nondimensionalized pressure drop plotted against the actual flow Reynolds number based on the porous medium permeability provided the following information. It was found that Darcy's law has very limited applicability and is valid for a small range of Reynolds numbers. This leads to a pre-Darcy flow that is valid for a much broader range of Reynolds numbers than expected. Alternatively, the range of validity of the post-Darcy laminar Forchheimer flow is also found to be of much more limited applicability than previous studies have indicated. Transition to turbulence takes place earlier than expected and turbulent flow prevails from then on. The dimensionless pressure drop in both the Forchheimer and turbulent flow regimes can be modeled by an appropriately nondimensionalized Ergun's equation i.e., a first-order inertia term correction is sufficient in both flow regimes.

  2. Turbulent flow of oil-water emulsions with polymer additives

    NASA Astrophysics Data System (ADS)

    Manzhai, V. N.; Monkam Clovis Le Grand, Monkam; Abdousaliamov, A. V.

    2014-08-01

    The article outlines direct and reverse oil-water emulsions. Microphotography study of these emulsions was carried out. The effect of water-soluble and oil soluble polymers on the emulsion structure and their turbulent flow velocity in cylindrical channel was investigated. It has been experimentally proven that if the fluid being transported is not homogeneous, but a two-phase oil-water emulsion, only the polymer that is compatible with dispersion medium and capable of dissolving in this medium can reduce the hydrodynamic resistance of the fluid flow. Thus, the resistance in direct emulsions can be reduced by water- soluble polyacrylamide, while oil-soluble polyhexene can be applied for reverse emulsions.

  3. Unexpected water flow through Nafion-tube punctures

    PubMed Central

    O’Rourke, Colin; Klyuzhin, Ivan; Park, Ji Sun; Pollack, Gerald H.

    2011-01-01

    When a Nafion tube is immersed in water and a small hole is punched in the tube’s wall, an unexpected phenomenon occurs: Water flows continuously into the tube through the hole. The phenomenon has proved repeatable, and dynamic aspects were therefore explored, including the effects of altered pH and introduction of a second hole. It appears that the flow is closely tied to the recently discovered “exclusion zone” that forms as an annulus inside the Nafion tube. These zones generate protons in the core of the tube, which exert pressure on the menisci; once a hole is punched, the pressure is relieved by sucking water through the hole. This hypothesis is consistent with the observed experimental evidence and may be relevant to the mechanism of water transport in trees. PMID:21728645

  4. Unexpected water flow through Nafion-tube punctures

    NASA Astrophysics Data System (ADS)

    O'Rourke, Colin; Klyuzhin, Ivan; Park, Ji Sun; Pollack, Gerald H.

    2011-05-01

    When a Nafion tube is immersed in water and a small hole is punched in the tube's wall, an unexpected phenomenon occurs: Water flows continuously into the tube through the hole. The phenomenon has proved repeatable, and dynamic aspects were therefore explored, including the effects of altered pH and introduction of a second hole. It appears that the flow is closely tied to the recently discovered “exclusion zone” that forms as an annulus inside the Nafion tube. These zones generate protons in the core of the tube, which exert pressure on the menisci; once a hole is punched, the pressure is relieved by sucking water through the hole. This hypothesis is consistent with the observed experimental evidence and may be relevant to the mechanism of water transport in trees.

  5. Unexpected water flow through Nafion-tube punctures.

    PubMed

    O'Rourke, Colin; Klyuzhin, Ivan; Park, Ji Sun; Pollack, Gerald H

    2011-05-01

    When a Nafion tube is immersed in water and a small hole is punched in the tube's wall, an unexpected phenomenon occurs: Water flows continuously into the tube through the hole. The phenomenon has proved repeatable, and dynamic aspects were therefore explored, including the effects of altered pH and introduction of a second hole. It appears that the flow is closely tied to the recently discovered "exclusion zone" that forms as an annulus inside the Nafion tube. These zones generate protons in the core of the tube, which exert pressure on the menisci; once a hole is punched, the pressure is relieved by sucking water through the hole. This hypothesis is consistent with the observed experimental evidence and may be relevant to the mechanism of water transport in trees. PMID:21728645

  6. Interaction between water flow and oxygen deficiency on growth in the infaunal brittle star Amphiura filiformis (Echinodermata: Ophiuroidea)

    NASA Astrophysics Data System (ADS)

    Nilsson, H. C.

    2000-12-01

    Interactions between 'oxygen concentration' (normoxia: >80% oxygen saturation, and hypoxia: 18% oxygen saturation) and 'water flow velocity' (low: 0.1 cm s -1, and moderate: 0.5 cm s -1) were studied on growth rates in the brittle star Amphiura filiformis in a flow-through aquaria system. Effects of 'sublethal predation' on growth rates were investigated as 'number of amputated arms' (1 and 3 arms) and 'amputation of the disk'. A significant interaction between oxygen concentration and water flow velocity was observed in mean arm regeneration rate, but in both flow velocities higher mean arm regeneration rates were observed in normoxia compared to hypoxia. In hypoxia a positive response in arm regeneration rate was observed in moderate flow compared to low flow velocity. In normoxia, however, no response to flow velocity was observed. The latter observation indicates that Amphiura filiformis is able to maintain the ventilation of the burrow at low flow velocities, but in low oxygen concentrations hydrodynamic forces seem to affect growth. A significant interaction between oxygen concentration and disk amputation was observed in both arm and disk regeneration rates, indicating that the disk is the major organ for gas exchange in this species. The number of arms amputated, however, did not affect mean arm regeneration rate. The results obtained in this study suggest that the secondary production in subtidal infaunal populations could be negatively affected by low oxygen concentrations and that this response is even more negative in combination with low flow velocities in the near-bottom water.

  7. Water flow and fin shape polymorphism in coral reef fishes.

    PubMed

    Binning, Sandra A; Roche, Dominique G

    2015-03-01

    Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (<100 m) along a reef profile (reef slope, crest, and back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for

  8. Fracture control of ground water flow and water chemistry in a rock aquitard

    USGS Publications Warehouse

    Eaton, T.T.; Anderson, M.P.; Bradbury, K.R.

    2007-01-01

    There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/Ss) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies. ?? 2007 National Ground Water Association.

  9. Flow based vs. demand based energy-water modelling

    NASA Astrophysics Data System (ADS)

    Rozos, Evangelos; Nikolopoulos, Dionysis; Efstratiadis, Andreas; Koukouvinos, Antonios; Makropoulos, Christos

    2015-04-01

    The water flow in hydro-power generation systems is often used downstream to cover other type of demands like irrigation and water supply. However, the typical case is that the energy demand (operation of hydro-power plant) and the water demand do not coincide. Furthermore, the water inflow into a reservoir is a stochastic process. Things become more complicated if renewable resources (wind-turbines or photovoltaic panels) are included into the system. For this reason, the assessment and optimization of the operation of hydro-power systems are challenging tasks that require computer modelling. This modelling should not only simulate the water budget of the reservoirs and the energy production/consumption (pumped-storage), but should also take into account the constraints imposed by the natural or artificial water network using a flow routing algorithm. HYDRONOMEAS, for example, uses an elegant mathematical approach (digraph) to calculate the flow in a water network based on: the demands (input timeseries), the water availability (simulated) and the capacity of the transmission components (properties of channels, rivers, pipes, etc.). The input timeseries of demand should be estimated by another model and linked to the corresponding network nodes. A model that could be used to estimate these timeseries is UWOT. UWOT is a bottom up urban water cycle model that simulates the generation, aggregation and routing of water demand signals. In this study, we explore the potentials of UWOT in simulating the operation of complex hydrosystems that include energy generation. The evident advantage of this approach is the use of a single model instead of one for estimation of demands and another for the system simulation. An application of UWOT in a large scale system is attempted in mainland Greece in an area extending over 130×170 km². The challenges, the peculiarities and the advantages of this approach are examined and critically discussed.

  10. Explore the impacts of river flow and quality on biodiversity for water resources management by AI techniques

    NASA Astrophysics Data System (ADS)

    Chang, Fi-John; Tsai Tsai, Wen-Ping; Chang, Li-Chiu

    2016-04-01

    Water resources development is very challenging in Taiwan due to her diverse geographic environment and climatic conditions. To pursue sustainable water resources development, rationality and integrity is essential for water resources planning. River water quality and flow regimes are closely related to each other and affect river ecosystems simultaneously. This study aims to explore the complex impacts of water quality and flow regimes on fish community in order to comprehend the situations of the eco-hydrological system in the Danshui River of northern Taiwan. To make an effective and comprehensive strategy for sustainable water resources management, this study first models fish diversity through implementing a hybrid artificial neural network (ANN) based on long-term observational heterogeneity data of water quality, stream flow and fish species in the river. Then we use stream flow to estimate the loss of dissolved oxygen based on back-propagation neural networks (BPNNs). Finally, the non-dominated sorting genetic algorithm II (NSGA-II) is established for river flow management over the Shihmen Reservoir which is the main reservoir in this study area. In addition to satisfying the water demands of human beings and ecosystems, we also consider water quality for river flow management. The ecosystem requirement takes the form of maximizing fish diversity, which can be estimated by the hybrid ANN. The human requirement is to provide a higher satisfaction degree of water supply while the water quality requirement is to reduce the loss of dissolved oxygen in the river among flow stations. The results demonstrate that the proposed methodology can offer diversified alternative strategies for reservoir operation and improve reservoir operation strategies for producing downstream flows that could better meet both human and ecosystem needs as well as maintain river water quality. Keywords: Artificial intelligence (AI), Artificial neural networks (ANNs), Non

  11. Fluctuating water depths affect American alligator (Alligator mississippiensis) body condition in the Everglades, Florida, USA

    USGS Publications Warehouse

    Brandt, Laura A.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Cherkiss, Michael S.; Mazzotti, Frank J.

    2016-01-01

    Successful restoration of wetland ecosystems requires knowledge of wetland hydrologic patterns and an understanding of how those patterns affect wetland plant and animal populations.Within the Everglades, Florida, USA restoration, an applied science strategy including conceptual ecological models linking drivers to indicators is being used to organize current scientific understanding to support restoration efforts. A key driver of the ecosystem affecting the distribution and abundance of organisms is the timing, distribution, and volume of water flows that result in water depth patterns across the landscape. American alligators (Alligator mississippiensis) are one of the ecological indicators being used to assess Everglades restoration because they are a keystone species and integrate biological impacts of hydrological operations through all life stages. Alligator body condition (the relative fatness of an animal) is one of the metrics being used and targets have been set to allow us to track progress. We examined trends in alligator body condition using Fulton’s K over a 15 year period (2000–2014) at seven different wetland areas within the Everglades ecosystem, assessed patterns and trends relative to restoration targets, and related those trends to hydrologic variables. We developed a series of 17 a priori hypotheses that we tested with an information theoretic approach to identify which hydrologic factors affect alligator body condition. Alligator body condition was highest throughout the Everglades during the early 2000s and is approximately 5–10% lower now (2014). Values have varied by year, area, and hydrology. Body condition was positively correlated with range in water depth and fall water depth. Our top model was the “Current” model and included variables that describe current year hydrology (spring depth, fall depth, hydroperiod, range, interaction of range and fall depth, interaction of range and hydroperiod). Across all models, interaction

  12. Effects of sea-level rise on ground water flow in a coastal aquifer system

    USGS Publications Warehouse

    Masterson, J.P.; Garabedian, S.P.

    2007-01-01

    The effects of sea-level rise on the depth to the fresh water/salt water interface were simulated by using a density-dependent, three-dimensional numerical ground water flow model for a simplified hypothetical fresh water lens that is similar to shallow, coastal aquifers found along the Atlantic coast of the United States. Simulations of sea-level rise of 2.65 mm/year from 1929 to 2050 resulted in an increase in water levels relative to a fixed datum, yet a net decrease in water levels relative to the increased sea-level position. The net decrease in water levels was much greater near a gaining stream than farther from the stream. The difference in the change in water levels is attributed to the dampening effect of the stream on water level changes in response to sea-level rise. In response to the decreased water level altitudes relative to local sea level, the depth to the fresh water/salt water interface decreased. This reduction in the thickness of the fresh water lens varied throughout the aquifer and was greatly affected by proximity to a ground water fed stream and whether the stream was tidally influenced. Away from the stream, the thickness of the fresh water lens decreased by about 2% from 1929 to 2050, whereas the fresh water lens thickness decreased by about 22% to 31% for the same period near the stream, depending on whether the stream was tidally influenced. The difference in the change in the fresh water/salt water interface position is controlled by the difference in the net decline in water levels relative to local sea level. ?? 2007 National Ground Water Association.

  13. What affects public acceptance of recycled and desalinated water?

    PubMed Central

    Dolnicar, Sara; Hurlimann, Anna; Grün, Bettina

    2011-01-01

    This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived. PMID:20950834

  14. Water chemistry of surface waters affected by the Fourmile Canyon wildfire, Colorado, 2010-2011

    USGS Publications Warehouse

    McCleskey, R. Blaine; Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    In September 2010, the Fourmile Canyon fire burned about 23 percent of the Fourmile Creek watershed in Boulder County, Colo. Water-quality sampling of Fourmile Creek began within a month after the wildfire to assess its effects on surface-water chemistry. Water samples were collected from five sites along Fourmile Creek (above, within, and below the burned area) monthly during base flow, twice weekly during snowmelt runoff, and at higher frequencies during storm events. Stream discharge was also monitored. Water-quality samples were collected less frequently from an additional 6 sites on Fourmile Creek, from 11 tributaries or other inputs, and from 3 sites along Boulder Creek. The pH, electrical conductivity, temperature, specific ultraviolet absorbance, total suspended solids, and concentrations (dissolved and total) of major cations (calcium, magnesium, sodium, and potassium), anions (chloride, sulfate, alkalinity, fluoride, and bromide), nutrients (nitrate, ammonium, and phosphorus), trace metals (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, strontium, vanadium, and zinc), and dissolved organic carbon are here reported for 436 samples collected during 2010 and 2011.

  15. Glaciation and regional ground-water flow in the Fennoscandian Shield: Site 94

    USGS Publications Warehouse

    Provost, Alden M.; Voss, Clifford I.; Neuzil, C.E.

    1998-01-01

    Results from a regional-scale ground-water flow model of the Fennoscandian shield suggest that ground-water flow is strongly affected by surface conditions associated with climatic change and glaciation. The model was used to run a series of numerical simulations of variable-density ground-water flow in a 1500-km-long and approximately 10-km-deep cross-section that passes through southern Sweden. Ground-water flow and shield brine transport in the cross-sectional model are controlled by an assumed time evolution of surface conditions over the next 140 ka. Simulations show that, under periglacial conditions, permafrost may locally or extensively impede the free recharge or discharge of ground water. Below cold-based glacial ice, no recharge or discharge of ground water occurs. Both of these conditions result in the settling of shield brine and consequent freshening of near-surface water in areas of natural discharge blocked by permafrost. The presence of warm-based ice with basal melting creates a potential for ground-water recharge rates much larger than under present, ice-free conditions. Recharging basal meltwater can reach depths of a few kilometers in a few thousand years. The vast majority of recharged water is accommodated through storage in the volume of bedrock below the local area of recharge; regional (lateral) redistribution of recharged water by subsurface flow is minor over the duration of a glacial advance (~10 ka). During glacial retreat, the weight of the ice overlying a given surface location decreases, and significant upward flow of ground water may occur below the ice sheet due to pressure release, despite the continued potential for recharge of basal meltwater. Excess meltwater must exit from below the glacier through subglacial cavities and channels. Subsurface penetration of meltwater during glacial advance and up-flow during glacial retreat are greatest if the loading efficiency of the shield rock is low. The maximum rate of ground-water

  16. Estimation of water withdrawal and distribution, water use, and wastewater collection and return flow in Cumberland, Rhode Island, 1988. Water resources investigation

    SciTech Connect

    Horn, M.A.; Craft, P.A.; Bratton, L.

    1994-12-31

    The purpose of the report is to demonstrate integration of water-use data collected by different State agencies or maintained by different public suppliers and wastewater-treatment facilities. The report presents a brief discussion of data compilation, organization and computer storage, and analysis. A detailed description of the methods used and the resulting water-use data are presented on withdrawal, distribution, use, wastewater collection, return flow, and import of water into and export of water out of Cumberland. At the end of each section, an overview provides a discussion of how water that is withdrawn, distributed, used, collected, and returned in the study area affects the availability and distribution of water resources.

  17. Carboxymethyl modification of konjac glucomannan affects water binding properties.

    PubMed

    Xiao, Man; Dai, Shuhong; Wang, Le; Ni, Xuewen; Yan, Wenli; Fang, Yapeng; Corke, Harold; Jiang, Fatang

    2015-10-01

    The water binding properties of konjac glucomannan (KGM) and carboxymethyl konjac glucomannan (CMKGM) are important for their application in food, pharmaceutical, and chemical engineering fields. The equilibrium moisture content of CMKGM was lower than that of KGM at the relative humidity in the range 30-95% at 25°C. The water absorption and solubility of CMKGM in water solution were lower than that of KGM at 25°C. Carboxymethyl modification of KGM reduces the water adsorption, absorption, and solubility. Both carboxymethylation and deacetylation could confer hydrophobicity for CMKGM. These data provide the basis for expanding CMKGM application. PMID:26076594

  18. Factors affecting response of surface waters to acidic deposition

    SciTech Connect

    Turner, R.S.; Johnson, D.W.; Elwood, J.W.; Van Winkle, W.; Clapp, R.B.; Reuss, J.O.

    1986-04-01

    Knowledge of watershed hydrology and of the biogeochemical reactions and elemental pools and fluxes occurring in watersheds can be used to classify the response of watersheds and surface waters to acidic deposition. A conceptual mosel is presented for classifying watersheds into those for which (1) surface water chemistry will change rapidly with deposition quality (direct response) (2) surface water chemistry will change only slowly over time (delayed response), and (3) surface water chemistry will not change significantly, even with continued acidic deposition (capacity-protected). Techniques and data available for classification of all watersheds in a region into these categories are discussed.

  19. Denitrification in Wood Chip Bioreactors at Different Water Flows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Subsurface drainage in agricultural watersheds exports a large quantity of nitrate-nitrogen (NO3-N) and concentrations frequently exceed 10 mg L-1. A laboratory column study was conducted to investigate the ability of a wood chip biofilter to promote denitrification under mean water flow rates of 2....

  20. Erosional processes in channelized water flows on Mars

    NASA Technical Reports Server (NTRS)

    Baker, V. R.

    1979-01-01

    A hypothesis is investigated according to which the Martian outflow channels were formed by high-velocity flows of water or dynamically similar liquid. It is suggested that the outflow channels are largely the result of several interacting erosional mechanisms, including fluvial processes involving ice covers, macroturbulence, streamlining, and cavitation.

  1. 19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. EMPTY SEDIMENTATION TANKS. TOP LAYER OF WATER FLOWS OVER TRIANGULATED CHANNELS AND OUT THE RAISED DUCTS TO FILTRATION PLANT. MOVEABLE BOARDS ON BOTTOM ASSIST IN REMOVING SLUDGE. VIEW LOOKING NORTHEAST. FILTER CONTROL BUILDING AT REAR. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  2. Water Flow Simulation using Smoothed Particle Hydrodynamics (SPH)

    NASA Technical Reports Server (NTRS)

    Vu, Bruce; Berg, Jared; Harris, Michael F.

    2014-01-01

    Simulation of water flow from the rainbird nozzles has been accomplished using the Smoothed Particle Hydrodynamics (SPH). The advantage of using SPH is that no meshing is required, thus the grid quality is no longer an issue and accuracy can be improved.

  3. 1. East apron upper dam with water flowing over overspill. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. East apron upper dam with water flowing over overspill. Photograph taken from crest of lower dam in foreground). VIEW WEST - Loleta Recreation Area, Upper Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  4. 15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW SHOWING WATER FLOWING THROUGH THE ORIGINAL DIVERSION GATE FROM THE OUTLET CHANNEL INTO THE BY-PASS CHANNEL LEADING TO THE ORIGINAL SOURIS RIVER CHANNEL (Note: this gate has since been replaced with concrete diversion gates, see HAER Photograph No ND-3-A-7) - Upper Souris National Wildlife Refuge, Dam 83, Souris River Basin, Foxholm, Surrey (England), ND

  5. Water-quality assessment of part of the Upper Mississippi River basin, Minnesota and Wisconsin - Ground-water quality along a flow system in the Twin Cities metropolitan area, Minnesota, 1997-98

    USGS Publications Warehouse

    Andrews, William J.; Stark, James R.; Fong, Alison L.; Fallon, James D.

    2005-01-01

    Although land use had substantial effects on ground-water quality, the distribution of contaminants in the aquifer also is affected by complex combinations of factors and processes that include sources of natural and anthropogenic contaminants, three-dimensional advective flow, physical and hydrologic settings, age and evolution of ground water, and transformation of chemical compounds along the flow system. Compounds such as nitrate and dissolved oxygen were greatest in water samples from the upgradient end of the flow system and near the water table. Specific conductance and dissolved solids increased along the flow system and with depth due to increase in residence time in the flow system and dissolution of aquifer materials.

  6. Fracture control of ground water flow and water chemistry in a rock aquitard.

    PubMed

    Eaton, Timothy T; Anderson, Mary P; Bradbury, Kenneth R

    2007-01-01

    There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/S(s)) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies. PMID:17760586

  7. Investigating Factors that Affect Dissolved Oxygen Concentration in Water

    ERIC Educational Resources Information Center

    Jantzen, Paul G.

    1978-01-01

    Describes activities that demonstrate the effects of factors such as wind velocity, water temperature, convection currents, intensity of light, rate of photosynthesis, atmospheric pressure, humidity, numbers of decomposers, presence of oxidizable ions, and respiration by plants and animals on the dissolved oxygen concentration in water. (MA)

  8. How Do Our Actions Affect Water Quantity and Quality?

    ERIC Educational Resources Information Center

    Gordon, Jessica

    2008-01-01

    Water is an essential resource for all living things. How we live on our watershed can impact water quantity and quality. It is important to recognize how humans alter watershed dynamics, but students often find it challenging to visualize watershed processes and understand how decisions that they make as individuals and together as a community…

  9. DO AUTOCHTHONOUS BACTERIA AFFECT GIARDIA CYST SURVIVAL IN NATURAL WATERS?

    EPA Science Inventory

    Giardia lamblia survives in and is transmitted to susceptible human and animal populations via water, where it is present in an environmentally resistant cyst form. Previous research has highlighted the importance of water temperature in cyst survival, and has also suggested the ...

  10. Space shuttle orbiter flow visualization study. [water tunnel study of vortex flow during atmospheric entry

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    The vortex flows generated at subsonic speed during the final portion of atmospheric reentry were defined using a 0.01 scale model of the orbiter in a diagnostic water tunnel. Flow visualization photographs were obtained over an angle-of-attack range to 40 deg and sideslip angles up to 10 deg. The vortex flow field development, vortex path, and vortex breakdown characteristics were determined as a function of angle-of-attack at zero sideslip. Vortex flows were found to develop on the highly swept glove, on the wing, and on the upper surface of the fuselage. No significant asymmetries were observed at zero sideslip in the water tunnel tests. The sensitivity of the upper surface vortex flow fields to variations in sideslip angle was also studied. The vortex formed on the glove remained very stable in position above the wing up through the 10 deg of sideslip tested. There was a change in the vortex lifts under sideslip due to effective change in leading-edge sweep angles. Asymmetric flow separation occurred on the upper surface of the fuselage at small sideslip angles. The influence of vortex flow fields in sideslip on the lateral/ directional characteristics of the orbiter is discussed.

  11. Volcanic water flows could have flooded Ganymede's planetary rift system

    SciTech Connect

    Allison, M.L.; Clifford, S.M.

    1985-01-01

    Global expansion on Ganymede of only 1 or 2% created a planetary rift system which was resurfaced over a significant period of the planet's history creating bright, grooved terrain. The most reasonable model entails flooding of grabens by water or slush magmas which rose to the surface along normal faults in the rift system. Various models exist for the origin of the water magmas including isostatic rise of freezing ice I or diapirs of unstable ice III. A model considering the heat balance at the surface of an ice-covered water flow is constructed with the simplifying assumption that both laminar flow and a solid ice cover are achieved relatively soon after eruption. The ice cover will thicken until the underlying flowing water is entirely frozen. Energy into the system comes from solar radiation and the latent heat of freezing. Energy lost will be by evaporative and radiative cooling at the ice surface and by conduction into the substratum. Solving the heat balance allows a prediction for the volume of magma that can flood the surface. For example a flow 5 m thick will take tens of days to freeze, so that discharge rates equal to that of average terrestrial basalt flows could flood relatively large areas of the surface before freezing. Volcanic flooding is therefore a physically viable mechanism for the origin of bright terrain. During freezing the water/ice volume increases, lifting and fracturing the ice cover. These fractures may localize continued tectonic forces producing large displacements and creating the present grooved terrain.

  12. Assessing changes in water flow regulation in Chongqing region, China.

    PubMed

    Xiao, Yang; Xiao, Qiang; Ouyang, Zhiyun; Maomao, Qin

    2015-06-01

    Water flow regulation is an important ecosystem service that significantly impacts on ecological quality and social benefits. With the aim of improving our understanding of ecosystems and proposing strategies for optimizing ecosystem services, a geographic information system (GIS)-based approach was designed to estimate and map regulated water flow in the Chongqing region of China. In this study, we applied the integrated valuation of environmental services and tradeoffs (InVEST) model and mathematical simulations to estimate the provision of the regulated water flow across space and time in 2000, 2005, and 2010. The results indicated that this ecosystem service had improved by 2.07 % from 2000 to 2010 as a result of human activities (such as vegetation restoration) and climatic interaction. Places with positive changes mainly occurred in high mountain areas, whereas places with negative changes were mainly distributed in resettlement areas along the Yangtze River. The type of ecosystem in areas with high mountains and steep slopes was a relatively minor contributor to the total service, but this ecosystem had the higher water flow regulation capacity. Moreover, with the increase in altitude and slope, the percentage contribution of forest increased significantly from 2000 to 2010; by contrast, the percentage contribution of cropland decreased rapidly. As for the impacts, the spatial variation of water flow regulation in the Chongqing region had a significant relation with climate and human activities at the regional scale. These results provided specific information that could be used to strengthen necessary public awareness about the protection and restoration of ecosystems. PMID:25980726

  13. Controlling water flow inside carbon nanotube with lipid membranes

    SciTech Connect

    Feng, Jia-Wei; Ding, Hong-Ming; Ma, Yu-Qiang

    2014-09-07

    Understanding and controlling the transportation of water molecules across carbon nanotube (CNT) is of great importance in bio-nanotechnology. In this paper, we systematically investigate the water transporting behaviors (i.e., water flow rate) inside the CNT in the presence of lipid membranes by using all atom molecular dynamic simulations. Our results show that the hydrophilicity of CNT as well as membrane thickness can have important impacts on the water flow rate. Interestingly, since the membrane thickness is temperature-dependent, the water flow rate can exhibit thermo-responsive behaviors. Further, we also provide insights into the effect of CNT on lipid membranes. It is found that all CNTs can increase the lipid tail order parameters and thicken the membrane at 320 K; while these effects are not obvious at 290 K. Importantly, we observe that the CNT with specific hydrophobicity has the least effect on membranes. The present study may give some useful advice on future experimental design of novel devices and sensors.

  14. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    NASA Astrophysics Data System (ADS)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  15. Influence of water flow on Neosho madtom (Noturus placidus) reproductive behavior

    USGS Publications Warehouse

    Bryan, J.L.; Wildhaber, M.L.; Noltie, D.B.

    2006-01-01

    The Neosho madtom is a small, short-lived catfish species endemic to gravel bars of the Neosho River in Kansas, Oklahoma and Missouri, U.S.A. It spawns during summer in nesting cavities excavated in gravel. Although the species has survived dam construction within the Neosho River basin, its declining numbers resulted in it being added to the federal threatened species list in 1991. To test how water flow affects the reproductive behavior of Neosho madtoms, we compared activities of male-female pairs in static versus flowing-water aquaria. Using a behavioral catalog, we recorded their behavior sequences during randomly selected 5-min nighttime periods. For males and females, Jostle and Embrace were the most performed reproductive behaviors and the Jostle-Embrace-Carousel was the most performed reproductive behavior sequence. Water flow decreased the mean frequency of occurrence, percentage of time spent and mean event duration of male Nest Building. Because Neosho madtom courtship, reproduction and parental care is a complex and extended process, disturbances such as heightened river flows during the species' spawning season may negatively affect nest quality and reproductive success.

  16. Assignment of boundary conditions in embedded ground water flow models

    USGS Publications Warehouse

    Leake, S.A.

    1998-01-01

    Many small-scale ground water models are too small to incorporate distant aquifer boundaries. If a larger-scale model exists for the area of interest, flow and head values can be specified for boundaries in the smaller-scale model using values from the larger-scale model. Flow components along rows and columns of a large-scale block-centered finite-difference model can be interpolated to compute horizontal flow across any segment of a perimeter of a small-scale model. Head at cell centers of the larger-scale model can be interpolated to compute head at points on a model perimeter. Simple linear interpolation is proposed for horizontal interpolation of horizontal-flow components. Bilinear interpolation is proposed for horizontal interpolation of head values. The methods of interpolation provided satisfactory boundary conditions in tests using models of hypothetical aquifers.Many small-scale ground water models are too small to incorporate distant aquifer boundaries. If a larger-scale model exists for the area of interest, flow and head values can be specified for boundaries in the smaller-scale model using values from the larger-scale model. Flow components along rows and columns of a large-scale block-centered finite-difference model can be interpolated to compute horizontal flow across any segment of a perimeter of a small-scale model. Head at cell centers of the larger.scale model can be interpolated to compute head at points on a model perimeter. Simple linear interpolation is proposed for horizontal interpolation of horizontal-flow components. Bilinear interpolation is proposed for horizontal interpolation of head values. The methods of interpolation provided satisfactory boundary conditions in tests using models of hypothetical aquifers.

  17. Petroleum coke adsorption as a water management option for oil sands process-affected water.

    PubMed

    Zubot, Warren; MacKinnon, Michael D; Chelme-Ayala, Pamela; Smith, Daniel W; Gamal El-Din, Mohamed

    2012-06-15

    Water is integral to both operational and environmental aspects of the oil sands industry. A water treatment option based on the use of petroleum coke (PC), a by-product of bitumen upgrading, was examined as an opportunity to reduce site oil sands process-affected water (OSPW) inventories and net raw water demand. Changes in OSPW quality when treated with PC included increments in pH levels and concentrations of vanadium, molybdenum, and sulphate. Constituents that decreased in concentration after PC adsorption included total acid-extractable organics (TAO), bicarbonate, calcium, barium, magnesium, and strontium. Changes in naphthenic acids (NAs) speciation were observed after PC adsorption. A battery of bioassays was used to measure the OSPW toxicity. The results indicated that untreated OSPW was toxic towards Vibrio fischeri and rainbow trout. However, OSPW treated with PC at appropriate dosages was not acutely toxic towards these test organisms. Removal of TAO was found to be an adsorption process, fitting the Langmuir and Langmuir-Freundlich isotherm models. For TAO concentrations of 60 mg/L, adsorption capacities ranged between 0.1 and 0.46 mg/g. This study demonstrates that freshly produced PC from fluid cokers provides an effective treatment of OSPW in terms of key constituents' removal and toxicity reduction. PMID:22575375

  18. Spatial development of the wind-driven water surface flow

    NASA Astrophysics Data System (ADS)

    Chemin, Rémi; Caulliez, Guillemette

    2015-04-01

    The water velocity field induced by wind and waves beneath an air-water interface is investigated experimentally versus fetch in the large Marseille-Luminy wind wave tank. Measurements of the vertical velocity profiles inside the subsurface shear layer were performed by a three-component Nortek acoustic Doppler velocimeter. The surface drift current was also derived from visualizations of small floating drifters recorded by a video camera looking vertically from above the water surface. Surface wave height and slopes were determined simultaneously by means of capacitance gauges and a single-point laser slope system located in the immediate vicinity of the profiler. Observations were made at steady low to moderate wind speeds and various fetches ranging between 1 and 15 meters. This study first corroborates that the thin subsurface water boundary layer forced by wind at the leading edge of the water sheet is laminar. The surface drift current velocity indeed increases gradually with fetch, following a 1/3 power law characteristic of an accelerated flat-plate laminar boundary layer. The laminar-turbulent transition manifests itself by a sudden decrease in the water surface flow velocity and a rapid deepening of the boundary layer due to the development of large-scale longitudinal vortices. Further downstream, when characteristic capillary-gravity wind waves develop at the surface, the water flow velocity increases again rapidly within a sublayer of typically 4 mm depth. This phenomenon is explained by the occurrence of an intense momentum flux from waves to the mean flow due to the dissipation of parasitic capillaries generated ahead of the dominant wave crests. This phenomenon also sustains significant small-scale turbulent motions within the whole boundary layer. However, when gravity-capillary waves of length longer than 10 cm then grow at the water surface, the mean flow velocity field decreases drastically over the whole boundary layer thickness. At the same

  19. Environmental Factors Affecting the Occurrence of Mycobacteria in Brook Waters

    PubMed Central

    Iivanainen, E. K.; Martikainen, P. J.; Väänänen, P. K.; Katila, M.-L.

    1993-01-01

    To evaluate the impact of environmental factors on the occurrence of environmental mycobacteria, viable counts of mycobacteria were measured in samples of brook water collected from 53 drainage areas located in a linear belt crossing Finland at 63° north latitude. The numbers of mycobacteria were correlated with characteristics of the drainage area, climatic parameters, chemical and physical characteristics of the water, and counts of other heterotrophic bacteria in the water. The numbers of mycobacteria in the water ranged from 10 to 2,200 CFU/liter. The counts correlated positively (P < 0.001) with the presence of peatlands, precipitation data, chemical oxygen demand, water color, and concentrations of Fe, Al, Cu, Co, and Cr. The mycobacterial counts correlated negatively (P < 0.001) with water pH, whereas other heterotrophic bacterial counts lacked any correlation with pH. A linear regression model with four independent variables (i.e., peatlands in the drainage area, chemical oxygen demand, concentration of potassium, and pH) explained 83% of the variation in mycobacterial counts in brook waters. Our results suggest that acidification may enhance the growth of environmental mycobacteria. PMID:16348866

  20. Dietary water affects human skin hydration and biomechanics

    PubMed Central

    Palma, Lídia; Marques, Liliana Tavares; Bujan, Julia; Rodrigues, Luís Monteiro

    2015-01-01

    It is generally assumed that dietary water might be beneficial for the health, especially in dermatological (age preventing) terms. The present study was designed to quantify the impact of dietary water on major indicators of skin physiology. A total of 49 healthy females (mean 24.5±4.3 years) were selected and characterized in terms of their dietary daily habits, especially focused in water consumption, by a Food Frequency Questionnaire. This allowed two groups to be set – Group 1 consuming less than 3,200 mL/day (n=38), and Group 2 consuming more than 3,200 mL/day (n=11). Approximately 2 L of water were added to the daily diet of Group 2 individuals for 1 month to quantify the impact of this surplus in their skin physiology. Measurements involving epidermal superficial and deep hydration, transepidermal water loss, and several biomechanical descriptors were taken at day 0 (T0), 15 (T1), and 30 (T2) in several anatomical sites (face, upper limb, and leg). This stress test (2 L/day for 30 days) significantly modified superficial and deep skin hydration, especially in Group 1. The same impact was registered with the most relevant biomechanical descriptors. Thus, in this study, it is clear that higher water inputs in regular diet might positively impact normal skin physiology, in particular in those individuals with lower daily water consumptions. PMID:26345226

  1. Flow variation and substrate type affect dislodgement of the freshwater polychaete, Manayunkia speciosa

    USGS Publications Warehouse

    Malakauskas, David M.; Wilson, Sarah J.; Wilzbach, Margaret A.; Som, Nicholas A.

    2013-01-01

    We quantified microscale flow forces and their ability to entrain the freshwater polychaete, Manayunkia speciosa, the intermediate host for 2 myxozoan parasites (Ceratomyxa shasta and Parvicapsula minibicornis) that cause substantial mortalities in salmonid fishes in the Pacific Northwest. In a laboratory flume, we measured the shear stress associated with 2 mean flow velocities and 3 substrates and quantified associated dislodgement of polychaetes, evaluated survivorship of dislodged polychaetes, and observed behavioral responses of the polychaetes in response to increased flow. We used a generalized linear mixed model to estimate the probability of polychaete dislodgement for treatment combinations of velocity (mean flow velocity  =  55 cm/s with a shear velocity  =  3 cm/s, mean flow velocity  =  140 cm/s with a shear velocity  =  5 cm/s) and substrate type (depositional sediments and analogs of rock faces and the filamentous alga, Cladophora). Few polychaetes were dislodged at shear velocities <3 cm/s on any substrate. Above this level of shear, probability of dislodgement was strongly affected by both substrate type and velocity. After accounting for substrate, odds of dislodgement were 8× greater at the higher flow. After accounting for velocity, probability of dislodgement was greatest from fine sediments, intermediate from rock faces, and negligible from Cladophora. Survivorship of dislodged polychaetes was high. Polychaetes exhibited a variety of behaviors for avoiding increases in flow, including extrusion of mucus, burrowing into sediments, and movement to lower-flow microhabitats. Our findings suggest that polychaete populations probably exhibit high resilience to flow-mediated disturbances.

  2. The Evolution of Water Concentration in Rhyolitic Lava Flows During Emplacement and Solidification and Effects on Development of Flow Textures

    NASA Astrophysics Data System (ADS)

    Seaman, S. J.; Bruce, L.

    2007-12-01

    Rhyolitic lava flows typically host spherulites, consist of radiating skeletal crystals of feldspar +/- quartz that nucleated on a crystal or a vapor bubble and/or flow bands. We have examined the association of mineral and rock microtextures with variations in water concentration in one flow banded, spherulite-bearing rhyolitic lava flow and two spherulite-bearing non-flow banded rhyolitic lava flows. All of the flows are approximately 24 Ma and are part of the Atascosa volcanic complex of southern Arizona. Fourier transform infrared microspectroscopy was used to analyze water concentrations and to map variations in water concentration across zones of interest in the samples. The Bartolo Mountain lava flow is flow banded, with gray thicker flow bands hosting larger, water-richer spherulites and glass, and orange thinner flow bands hosting smaller, water-poorer spherulites and glass. Skeletal crystals vary in their water concentrations, but water preferentially was partitioned into the surrounding glass during spherulite formation, which occurred during flow of the lava. Textures and water concentration variations suggest that flow banding reflects primary variations in water concentration in the melt, possibly associated with stretching of vesicles as the magma flowed. Spherulites from the Hell's Gate lava flow consist of two or more generations of skeletal radiating crystals, with each successive generation nucleating on the end of crystals of the previous generation. Single skeletal crystals are up to 300 microns in length, and are wider nearer the core of the spherulites. Water concentrations generally increases along the length of each generation of sanidine needles, although oscillation of water concentration has been observed. Water concentration also generally increases from the innermost sanidine generation to those that successively overgrow the spherulite. Overall, water concentration increases from approximately 600 ppm in the cores of spherlites to

  3. How Circulation of Water Affects Freezing in Ponds

    ERIC Educational Resources Information Center

    Moreau, Theresa; Lamontagne, Robert; Letzring, Daniel

    2007-01-01

    One means of preventing the top of a pond from freezing involves running a circulating pump near the bottom to agitate the surface and expose it to air throughout the winter months. This phenomenon is similar to that of the flowing of streams in subzero temperatures and to the running of taps to prevent pipe bursts in winter. All of these cases…

  4. Generation of pyroclastic flows by explosive interaction of lava flows with ice/water-saturated substrate

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Behncke, Boris; Belousova, Marina

    2011-04-01

    We describe a new type of secondary rootless phreatomagmatic explosions observed at active lava flows at volcanoes Klyuchevskoy (Russia) and Etna (Italy). The explosions occurred at considerable (up to 5 km) distances from primary volcanic vents, generally at steep (15-35°) slopes, and in places where incandescent basaltic or basaltic-andesitic lava propagated over ice/water-saturated substrate. The explosions produced high (up to 7 km) vertical ash/steam-laden clouds as well as pyroclastic flows that traveled up to 2 km downslope. Individual lobes of the pyroclastic flow deposits were up to 2 m thick, had steep lateral margins, and were composed of angular to subrounded bomb-size clasts in a poorly sorted ash-lapilli matrix. Character of the juvenile rock clasts in the pyroclastic flows (poorly vesiculated with chilled and fractured cauliflower outer surfaces) indicated their origin by explosive fragmentation of lava due to contact with external water. Non-juvenile rocks derived from the substrate of the lava flows comprised up to 75% in some of the pyroclastic flow deposits. We suggest a model where gradual heating of a water-saturated substrate under the advancing lava flow elevates pore pressure and thus reduces basal friction (in the case of frozen substrate water is initially formed by thawing of the substrate along the contact with lava). On steep slope this leads to gravitational instability and sliding of a part of the active lava flow and water-saturated substrate. The sliding lava and substrate disintegrate and intermix, triggering explosive "fuel-coolant" type interaction that produces large volume of fine-grained clastic material. Relatively cold steam-laden cloud of the phreatomagmatic explosion has limited capacity to transport upward the produced clastic material, thus part of it descends downslope in the form of pyroclastic flow. Similar explosive events were described for active lava flows of Llaima (Chile), Pavlof (Alaska), and Hekla (Iceland

  5. A guide for using the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    USGS Publications Warehouse

    Blainey, Joan B.; Faunt, Claudia C.; Hill, Mary C.

    2006-01-01

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  6. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    SciTech Connect

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  7. Evaluation of water cooled supersonic temperature and pressure probes for application to 1366 K flows

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas; Seiner, John M.

    1990-01-01

    Water cooled supersonic probes are developed to investigate total pressure, static pressure, and total temperature in high-temperature jet plumes and thereby determine the mean flow properties. Two probe concepts, designed for operation at up to 1366 K in a Mach 2 flow, are tested on a water cooled nozzle. The two probe designs - the unsymmetric four-tube cooling configuration and the symmetric annular cooling design - take measurements at 755, 1089, and 1366 K of the three parameters. The cooled total and static pressure readings are found to agree with previous test results with uncooled configurations. The total-temperature probe, however, is affected by the introduction of water coolant, and effect which is explained by the increased heat transfer across the thermocouple-bead surface. Further investigation of the effect of coolant on the temperature probe is proposed to mitigate the effect and calculate more accurate temperatures in jet plumes.

  8. Continuous-Flow System Produces Medical-Grade Water

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Dahl, Roger W.; Wheeler, Richard R.

    2009-01-01

    A continuous-flow system utilizes microwave heating to sterilize water and to thermally inactivate endotoxins produced in the sterilization process. The system is designed for use in converting potable water to medical-grade water. Systems like this one could be used for efficient, small-scale production of medical- grade water in laboratories, clinics, and hospitals. This system could be adapted to use in selective sterilization of connections in ultra-pure-water-producing equipment and other equipment into which intrusion by microorganisms cannot be tolerated. Lightweight, port - able systems based on the design of this system could be rapidly deployed to remote locations (e.g., military field hospitals) or in response to emergencies in which the normal infrastructure for providing medical-grade water is disrupted. Larger systems based on the design of this system could be useful for industrial production of medical-grade water. The basic microwave-heating principle of this system is the same as that of a microwave oven: An item to be heated, made of a lossy dielectric material (in this case, flowing water) is irradiated with microwaves in a multimode microwave cavity. The heating is rapid and efficient because it results from absorption of microwave power throughout the volume of the lossy dielectric material. In this system, a copper tube having a length of 49.5 cm and a diameter of 2.25 cm serves as both the microwave cavity and the sterilization chamber. Microwave power is fed via a coaxial cable to an antenna mounted inside the tube at mid-length (see figure). Efficient power transfer occurs due to the shift in wavelength associated with the high permittivity of water combined with the strong coupling of 2.45-GHz microwaves with rotational-vibrational transitions of the dipolar water molecule.

  9. Physical-Chemical Factors Affecting the Low Quality of Natural Water in the Khibiny Massif

    NASA Astrophysics Data System (ADS)

    Mazukhina, Svetlana; Masloboev, Vladimir; Chudnenko, Konstantin; Maksimova, Viktoriia; Belkina, Natalia

    2014-05-01

    One peculiarity of the Khibiny Massif is its spatial location. Rising over 1000 m above the surrounding hilly land and thus obstructing the passage of air masses, it promotes condensation and accumulation of surface and underground water. Annual precipitation here amounts to 600-700 mm in the valleys and up to 1600 mm on mountainous plateaus. Using this water for drinking and household purposes is problematic due to excess Al and F concentrations and high pH values. Now it is known that in its profile, the Massif is represented by three hydrogeological subzones: the upper (aerated), medium and lower ones. The upper subzone spreads throughout the Massif and is affected by the local drainage network and climatic conditions. The medium subzone is permanently saturated with underground water flowing horizontally to sites of discharge at the level of local river valleys and lakes. The fissure-vein water in the lower subzone is confined to tectonic fractures and faults in the so far underexplored, deeper parts of the Massif. Being abundant, this water ascends under high pressure. At places, water has been observed spurting from as deep as 700 m, and even 960 m. In the latter case, the temperature of ascending water was higher than 18 centigrade (Hydrogeology of the USSR, V. 27, 1971). This work was undertaken to reveal the nature of the low quality of water in the Khibiny by using physical-chemical modeling (software package Selector, Chudnenko, 2010). Processes of surface and underground water formation in the Khibiny were examined within a physical-chemical model (PCM) of the "water-rock-atmosphere-hydrogen" system. In a multi-vessel model used, each vessel represented a geochemical level of the process interpreted as spatiotemporal data - ξ (Karpov, 1981). The flow reactor consisted of 4 tanks. In the first tank, water of the Kuniok River (1000 L) interacted with atmosphere and an organic substance. The resulting solution proceeded to tanks 2-4 containing with

  10. Phosphate Ions Affect the Water Structure at Functionalized Membrane Surfaces.

    PubMed

    Barrett, Aliyah; Imbrogno, Joseph; Belfort, Georges; Petersen, Poul B

    2016-09-01

    Antifouling surfaces improve function, efficiency, and safety in products such as water filtration membranes, marine vehicle coatings, and medical implants by resisting protein and biofilm adhesion. Understanding the role of water structure at these materials in preventing protein adhesion and biofilm formation is critical to designing more effective coatings. Such fouling experiments are typically performed under biological conditions using isotonic aqueous buffers. Previous studies have explored the structure of pure water at a few different antifouling surfaces, but the effect of electrolytes and ionic strength (I) on the water structure at antifouling surfaces is not well studied. Here sum frequency generation (SFG) spectroscopy is used to characterize the interfacial water structure at poly(ether sulfone) (PES) and two surface-modified PES films in contact with 0.01 M phosphate buffer with high and low salt (Ionic strength, I= 0.166 and 0.025 M, respectively). Unmodified PES, commonly used as a filtration membrane, and modified PES with a hydrophobic alkane (C18) and with a poly(ethylene glycol) (PEG) were used. In the low ionic strength phosphate buffer, water was strongly ordered near the surface of the PEG-modified PES film due to exclusion of phosphate ions and the creation of a surface potential resulting from charge separation between phosphate anions and sodium cations. However, in the high ionic strength phosphate buffer, the sodium and potassium chloride (138 and 3 mM, respectively) in the phosphate buffered saline screened this charge and substantially reduced water ordering. A much smaller water ordering and subsequent reduction upon salt addition was observed for the C18-modified PES, and little water structure change was seen for the unmodified PES. The large difference in water structuring with increasing ionic strength between widely used phosphate buffer and phosphate buffered saline at the PEG interface demonstrates the importance of studying

  11. Onset of entrainment and degree of dispersion in dual continuous horizontal oil-water flows

    SciTech Connect

    Al-Wahaibi, Talal; Angeli, Panagiota

    2009-04-15

    The transition from stratified to dual continuous oil-water flow (where each phase retains its continuity but there is dispersion of one phase into the other) as well as the dispersed phase fractions in the layers of the dual continuous pattern, were studied experimentally. Transition to this pattern from stratified flow occurs when drops of one phase appear into the other (onset of entrainment). The studies were carried out in a 38 mm ID horizontal stainless steel test section using two different inlet geometries, a T- and a Y-junction. The patterns were visualized through a transparent acrylic section located at 7 m from the inlet using a high speed video camera. Phase distribution measurements in a pipe cross section were obtained just before the acrylic section with a local impedance probe and the results were used to calculate the volume fraction of each phase entrained into the other. The onset of entrainment was found to occur at lower superficial water velocities as the oil superficial velocities increased. However, the inlet geometry did not affect significantly the transition line. During dual continuous flow, the dispersion of one phase into the opposite was found to extend further away from the interface with increasing water superficial velocity for a certain oil superficial velocity. An increase in the superficial water velocity increased the entrained fraction of water in oil (E{sub w/o}) but there was no trend with the oil velocity. Similarly, an increase in the superficial oil velocity increased the fraction of oil drops in water (E{sub o/w}) but the water velocity had no clear effect. The entrainment fractions were affected by the inlet geometry, with the T-inlet resulting in higher entrainment than the Y-inlet, perhaps because of the increased mixing induced by the T-inlet. The difference between the two inlets increased as the oil and water velocities increased. (author)

  12. A mesocosm experiment of suspended particulate matter dynamics in nutrient- and biomass-affected waters.

    PubMed

    Tang, Fiona H M; Maggi, Federico

    2016-02-01

    An experimental study was conducted to test the hypothesis that the biomass growing after an increase in available nutrient in an aquatic ecosystem affects the flocculation dynamics of suspended particulate matter (SPM). The experiment was carried out in a settling column equipped with a turbulence generating system, a water quality monitoring system, and an automated μPIV system to acquire micro photographs of SPM. Three SPM types were tested combinatorially at five turbulence shear rates, three nutrient concentrations, and three mineral concentrations. Analyses of experimental data showed that nutrient availability together with the presence of biomass increased the SPM size by about 60% at low shear as compared to nutrient- and biomass-free conditions; a lower increase was observed at higher shears. In contrast, only 2% lower fractal (capacity) dimension and nearly invariant settling velocity were observed than in nutrient- and biomass-free conditions. Likewise, SPM size and capacity dimension were found to be insensitive to the SPM concentration. Although limited to nearly homogeneous mineral mixes (kaolinite), these experimental findings not only reject the hypothesis that SPM in natural waters can be dealt with as purely mineral systems in all instances, but also anticipate that SPM dynamics in natural waters increasingly exposed to the threat of anthropogenic nutrient discharge would lead to an increased advective flow of adsorbed chemicals and organic carbon. PMID:26641013

  13. Soil water balance as affected by throughfall in gorse ( Ulex europaeus, L.) shrubland after burning

    NASA Astrophysics Data System (ADS)

    Soto, Benedicto; Diaz-Fierros, Francisco

    1997-08-01

    The role of fire in the hydrological behaviour of gorse shrub is studied from the point of view of its effects on vegetation cover and throughfall. In the first year after fire, throughfall represents about 88% of gross rainfall, whereas in unburnt areas it is 58%. Four years after fire, the throughfall coefficients are similar in burnt and unburnt plots (about 6096). The throughfall is not linearly related to vegetation cover because an increase in cover does not involve a proportional reduction in throughfall. The throughfall predicted by the two-parameter exponential model of Calder (1986, J. Hydrol., 88: 201-211) provides a good fit with the observed throughfall and the y value of the model reflects the evolution of throughfall rate. The soil moisture distribution is modified by fire owing to the increase of evaporation in the surface soil and the decrease of transpiration from deep soil layers. Nevertheless, the use of the old root system by sprouting vegetation leads to a soil water profile in which 20 months after the fire the soil water is similar in burnt and unburnt areas. Overall, soil moisture is higher in burnt plots than in unburnt plots. Surface runoff increases after a fire but does not entirely account for the increase in throughfall. Therefore the removal of vegetation cover in gorse scrub by fire mainly affects the subsurface water flows.

  14. Flow enhancement of water flow through silica slit pores with graphene-coated walls

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    Nanofluidic devices such as Lab-On-a-Chip often are designed to transport water solutions through hydrophilic nano-conduits. In these systems with narrow confinement, the viscous forces dominate the flow and as a result, the hydrodynamic friction drag is very high. Moreover, the drag and the amount of energy required for pumping a fluid are directly related. Therefore, it is desirable to explore drag reduction strategies in nanoconfined flows. Liquids are known to slip past non-wetting surfaces. Graphene is a single-atom-thick sheet of carbon atoms arranged in a hexagonal honeycomb lattice, which features a unparalleled combination of high specific surface area, chemical stability, mechanical strength and flexibility. Recently, the wettability of water droplets on multilayer graphene sheets deposited on a silica substrate has been investigated. In this study, we investigate the role of graphene coatings to induce flow enhancement in silica channels. We conduct molecular dynamics simulations of pressurized water flow inside silica channels with and without graphene layers covering the walls. In particular, we compute density and velocity profiles, flow enhancement and slip lengths to understand the drag reduction capabilities of multilayer graphene coatings. We aknowledge partial support from Fondecyt project 11130559.

  15. Behavior of a shallow water table under periodic flow conditions

    NASA Astrophysics Data System (ADS)

    Cartwright, Nick; Nielsen, Peter; Perrochet, Pierre

    2009-03-01

    A new laboratory data set on the behavior of a shallow water table in a sand column aquifer subject to simple harmonic periodic forcing at its base is presented and discussed. The data are analyzed using the dynamic effective porosity, which is defined as the ratio of the rate of change in total moisture to the rate of change in water table elevation; thus, a reduction in this parameter means that the extent of moisture exchange has been reduced relative to a given water table fluctuation. The data show a clear decrease in the dynamic effective porosity with increasing proximity of the water table to the sand surface, which is consistent with previous research under a steadily rising or falling shallow water table. The observed reduction in moisture exchange due to shallowness of the water table has implications for periodic flow scenarios such as the propagation of water table waves in coastal and beach groundwater systems. That is, as moisture exchange is reduced, less work is being done by the flow, and thus, energy dissipation rates for shallow water tables will be reduced relative to the case of a deeper water table. At present no account of the influence of water table shallowness has been included in theories describing water table wave dispersion. The present experiments, in conjunction with the dynamic effective porosity concept, provide a framework in which this gap in knowledge can be further investigated. Additional experiments were designed such that the free surface transgressed the sand surface for part of the oscillation period to investigate the influence of meniscus formation and deformation at the sand surface on periodic flow dynamics. The observed behavior is consistent with previous observations of steady infiltration above shallow water tables, namely, a rapid drop (rise) in pore pressure with the onset of meniscus formation (deformation). A simple "wetting and drying" model is derived, accounting for the variation in effective porosity

  16. Virtual water flows and Water Balance Impacts of the U.S. Great Lakes Basin

    NASA Astrophysics Data System (ADS)

    Ruddell, B. L.; Mayer, A. S.; Mubako, S. T.

    2014-12-01

    To assess the impacts of human water use and trade on water balances, we estimate virtual water flows for counties in the U.S. portion of the Great Lakes basin. This is a water-rich region, but one where ecohydrological 'hotspots' are created by water scarcity in certain locations (Mubako et al., 2012). Trade shifts water uses from one location to another, causing water scarcity in some locations but mitigating water scarcity in other locations. A database of water withdrawals was assembled to give point-wise withdrawals by location, source, and use category (commercial, thermoelectric power, industrial, agricultural, mining). Point-wise consumptive use is aggregated to the county level, giving direct, virtual water exports by county. A county-level trade database provides import and export data for the various use categories. We link the annual virtual water exported from a county for a given use category to corresponding annual trade exports. Virtual water balances for each county by use category are calculated, and then compared with the renewable annual freshwater supply. Preliminary findings are that overall virtual water balances (imports - exports) are positive for almost all counties, because urban areas import goods and services that are more water intensive than the exported goods and services. However, for some agriculturally-intensive counties, the overall impact of virtual water trade on the water balance is close to zero, and the balance for agricultural sector virtual water trade is negative, reflecting a net impact of economic trade on the water balance in these locations. We also compare the virtual water balance to available water resources, using annual precipitation less evapotranspiration as a crude estimate of net renewable water availability. In some counties virtual water exports approach 30% of the available water resources, indicating the potential for water scarcity, especially from an aquatic ecosystem standpoint.

  17. Uncovering regional disparity of China's water footprint and inter-provincial virtual water flows.

    PubMed

    Dong, Huijuan; Geng, Yong; Fujita, Tsuyoshi; Fujii, Minoru; Hao, Dong; Yu, Xiaoman

    2014-12-01

    With rapid economic development in China, water crisis is becoming serious and may impede future sustainable development. The uneven distribution of water resources further aggravates such a problem. Under such a circumstance, the concepts of water footprint and virtual water have been proposed in order to respond water scarcity problems. This paper focuses on studying provincial disparity of China's water footprints and inter-provincial virtual water trade flows by adopting inter-regional input-output (IRIO) method. The results show that fast developing areas with larger economic scales such as Guangdong, Jiangsu, Shandong, Zhejiang, Shanghai and Xinjiang had the largest water footprints. The most developed and water scarce areas such as Shanghai, Beijing, Tianjin and Shandong intended to import virtual water, a rational choice for mitigating their water crisis. Xinjiang, Jiangsu, Heilongjiang, Inner Mongolia, Guangxi and Hunan, had the largest per GDP water intensities and were the main water import regions. Another key finding is that agriculture water footprint was the main part in water footprint composition and water export trade. On the basis of these findings, policy implications on agriculture geographical dispersion, consumption behavior changes, trade structure adjustment and water use efficiency improvement are further discussed. PMID:25222751

  18. Grid resolution study of ground water flow and transport.

    PubMed

    Bower, Kathleen M; Gable, Carl W; Zyvoloski, George A

    2005-01-01

    Three-dimensional grids representing a heterogeneous, ground water system are generated at 10 different resolutions in support of a site-scale flow and transport modeling effort. These grids represent hydrostratigraphy near Yucca Mountain, Nevada, consisting of 18 stratigraphic units with contrasting fluid flow and transport properties. The grid generation method allows the stratigraphy to be modeled by numerical grids of different resolution so that comparison studies can be performed to test for grid quality and determine the resolution required to resolve geologic structure and physical processes such as fluid flow and solute transport. The process of generating numerical grids with appropriate property distributions from geologic conceptual models is automated, thus making the entire process easy to implement with fewer user-induced errors. The series of grids of various resolutions are used to assess the level at which increasing resolution no longer influences the flow and solute transport results. Grid resolution is found to be a critical issue for ground water flow and solute transport. The resolution required in a particular instance is a function of the feature size of the model, the intrinsic properties of materials, the specific physics of the problem, and boundary conditions. The asymptotic nature of results related to flow and transport indicate that for a hydrologic model of the heterogeneous hydrostratigraphy under Yucca Mountain, a horizontal grid spacing of 600 m and vertical grid spacing of 40 m resolve the hydrostratigraphic model with sufficient precision to accurately model the hypothetical flow and solute transport to within 5% of the value that would be obtained with much higher resolution. PMID:15726930

  19. Turbulent flow over an interactive alternating land-water surface

    NASA Astrophysics Data System (ADS)

    Van Heerwaarden, C.; Mellado, J. P.

    2014-12-01

    The alternating land-water surface is a challenging surface to represent accurately in weather and climate models, but it is of great importance for the surface energy balance in polar regions. The complexity of this surface lies in the fact that secondary circulations, which form at the boundary of water and land, interact strongly with the surface energy balance. Due to its large heat capacity, the water temperature adapts slowly to the flow, thus the properties of the atmosphere determine the uptake of energy from the water. In order to study this complex system in a simpler way, retaining only the most essential physics, we have simplified the full surface energy balance including radiation. We have derived a boundary condition that mimics the full balance and can be formulated as a so-called Robin boundary condition: a linear combination of Dirichlet (fixed temperature) and Neumann (fixed temperature gradient) ones. By spatially varying the coefficients, we are able to express land and water using this boundary condition. We have done a series of direct numerical simulations in which we generate artificial land-water patterns from noise created from a Gaussian spectrum centered around a dominant wave number. This method creates realistic random patterns, but we are still in control of the length scales. We show that the system can manifest itself in three regimes: micro-, meso- and macro-scale. In the micro-scale, we find perfect mixing of the near-surface atmosphere that results in identical air properties over water and land. In the meso-scale, secondary circulations alter the heat exchange considerably by advecting air between land and water. In addition, they bring the surface temperature of the land closer to that of the air, thereby modulating the energy loss due to outgoing longwave radiation. In the macro-scale regime, the flow over land and water become independent of each other and only the large scale forcings determine the energy balance.

  20. The Properties of Confined Water and Fluid Flow at the Nanoscale

    SciTech Connect

    Schwegler, E; Reed, J; Lau, E; Prendergast, D; Galli, G; Grossman, J C; Cicero, G

    2009-03-09

    This project has been focused on the development of accurate computational tools to study fluids in confined, nanoscale geometries, and the application of these techniques to probe the structural and electronic properties of water confined between hydrophilic and hydrophobic substrates, including the presence of simple ions at the interfaces. In particular, we have used a series of ab-initio molecular dynamics simulations and quantum Monte Carlo calculations to build an understanding of how hydrogen bonding and solvation are modified at the nanoscale. The properties of confined water affect a wide range of scientific and technological problems - including protein folding, cell-membrane flow, materials properties in confined media and nanofluidic devices.

  1. Characterizing water flows in irrigated valleys of northern New Mexico

    NASA Astrophysics Data System (ADS)

    Ochoa, C. G.; Fernald, A.; Guldan, S.; Tidwell, V. C.

    2009-12-01

    Ditch seepage and deep percolation from irrigation in agricultural valleys of semi-arid regions can have multiple hydrological benefits including aquifer recharge, temporary storage, and delayed return flow. This study aims to advance scientific understanding of surface water and groundwater interactions in semi-arid region valleys of the western USA. The study is being conducted in three different irrigated valleys of the Rio Grande basin in northern New Mexico. The first site is a floodplain valley along the main stem of the Rio Grande; the second site is an upper valley along the Rio Hondo, a tributary to the Rio Grande; and the third site is a floodplain valley along the Rio Chama, which also is a tributary to the Rio Grande. Beginning in 2002, we instrumented the first study site to measure climate variables, surface water flows, and groundwater fluctuations due to deep percolation from irrigation and ditch seepage. Currently, we are installing field equipment at the second study site, and we will start instrumentation at the third study site in the spring of 2010. A multi-modeling approach is being used to extrapolate field-based results to larger spatial scales. One and two dimensional models like the Root Zone Water Quality Model and Hydrus, respectively, are being used to simulate physical processes in the vadose zone at the field scale, and the model GSFlow will be used to integrate surface water and groundwater components at the valley scale. Results from an ongoing study aimed to quantify water budget components at the first study site showed that up to 92% of the water diverted for irrigation in this floodplain valley returns back to the river, either as surface return flow (59%) or as shallow groundwater return flow that originated as canal seepage (12%) and deep percolation from irrigation (21%). Also, simulations with a System Dynamics Model showed that the coupled surface water irrigation system and shallow aquifer act together to store water

  2. Factors affecting milk flow traits in dairy cows: results of a field study.

    PubMed

    Sandrucci, A; Tamburini, A; Bava, L; Zucali, M

    2007-03-01

    The study of milk flow curves provides useful information for enhancing milking efficiency and protecting udder health by adapting milking machine and milking procedures to the physiological requirements of the cow. The aim of this experiment was to investigate, using field data, the relationships among traits of the milk flow curves, their sources of variation, and milking performances in terms of milk production, machine-on time, and udder health. A total of 2,486 milk flow curves of the whole udder were collected in 82 Italian Holstein-Friesian dairy herds in the Lombardy region of Italy. Approximately one-third (35.1%) of milk flow curves were classified as bimodal. Most flow characteristics were influenced by lactation number, days in milk, and peak flow but also strongly affected by premilking operations. Proper udder preparation, including forestripping and predipping, resulted in better milking performances compared with poor preparation, with greater milk yield per milking, shorter milking time, and lesser bimodality. Premilking delay time, between the start of teat stimulation and cup attachment, affected milking time significantly: The shortest milking time was obtained for a range of delay time between 1 and 60 s. As the delay time increased, the percentage of bimodality dropped significantly. Increasing the number of clusters per operator led to greater percentages of bimodal curves. The greater somatic cell count of cows with bimodal curves supports the hypothesis of the negative effect of bimodality on udder health and indicates the importance of avoiding its occurrence using proper pre-milking procedures. PMID:17297090

  3. Fragility Curve Construction for Low-Rise Reinforced Concrete Buildings Affected by Debris Flow

    NASA Astrophysics Data System (ADS)

    Akbas, S.; Sterlacchini, S.

    2009-04-01

    In landslide risk research, the majority of past studies has focused on hazard analysis, landslide zonation, and modeling, but there is limited amount of work on the concept of vulnerability, with no consensus on a generalized methodology. However, assessment of vulnerabilities along with the associated uncertainties are of utmost importance from a quantitative risk analysis point of view. This study aims at estimating the vulnerability by developing fragility curves, specifically for low-rise reinforced concrete buildings affected by debris flows. The effect of debris flow on structures is modeled as an impulsive load. The behavior of a structure under an impulsive load is in many ways is similar to that of an earthquake excitation. Based on this similarity, and using a well developed approach from the field of earthquake engineering, corresponding fragility curves are constructed for three structural damage limit states: serviceability, damage control, and collapse prevention. This is achieved by (1) representing the buildings as equivalent single degree-of-freedom systems, and conducting nonlinear time history analyses of these systems, (2) obtaining response statistics in terms of maximum displacement, (3) obtaining the conditional probability of attainment or exceedance of each limit state at a specific debris flow intensity level, and (4) plotting the computed conditional probability with respect to the selected debris flow hazard parameter. The resulting fragility curves give the damage state probability as a function of debris flow velocity. The uncertainty in the structural parameters, such as the natural period, are considered by using a building database from the city of Duzce, Turkey, which was affected by two major earthquakes in 1999. The comparison of the results obtained from this study with those obtained using a different database employing the same methodology, will highlight if the country-specific characteristics of the fragility curves are

  4. Influence of lateral subsurface flow and connectivity on soil water storage in land surface modeling

    NASA Astrophysics Data System (ADS)

    Kim, Jonggun; Mohanty, Binayak P.

    2016-01-01

    Lateral surface/subsurface flow and their connectivity play a significant role in redistributing soil water, which has a direct effect on biological, chemical, and geomorphological processes in the root zone (~1 m). However, most of the land surface models neglect the horizontal exchanges of water at the grid or subgrid scales, focusing only on the vertical exchanges of water as one-dimensional process. To develop better hydrologic understanding and modeling capability in complex landscapes, in this study we added connectivity-based lateral subsurface flow algorithms in the Community Land Model. To demonstrate the impact of lateral flow and connectivity on soil water storage we designed three cases including the following: (1) with complex surface topography only, (2) with complex surface topography in upper soil layers and soil hydraulic properties with uniform anisotropy. and (3) with complex surface topography and soil hydraulic properties with spatially varying anisotropy. The connectivity was considered as an indicator for the variation of anisotropy in the case 3, which was created by wetness conditions or geophysical controls (e.g., soil type, normalized difference vegetation index, and topographic index). These cases were tested in two study sites (ER 5 field and ER-sub watershed in Oklahoma) comparing to the field (gravimetric and remote sensing) soil moisture observations. Through the analysis of spatial patterns and temporal dynamics of soil moisture predictions from the study cases, surface topography was found to be a crucial control in demonstrating the variation of near surface soil moisture, but not significantly affected the subsurface flow in deeper soil layers. In addition, we observed the best performance in case 3 representing that the lateral connectivity can contribute effectively to quantify the anisotropy and redistributing soil water in the root zone. Hence, the approach with connectivity-based lateral subsurface flow was able to better

  5. Rain and channel flow supplements to subsurface water beneath hyper-arid ephemeral stream channels

    NASA Astrophysics Data System (ADS)

    Kampf, Stephanie K.; Faulconer, Joshua; Shaw, Jeremy R.; Sutfin, Nicholas A.; Cooper, David J.

    2016-05-01

    In hyper-arid regions, ephemeral stream channels are important sources of subsurface recharge and water supply for riparian vegetation, but few studies have documented the subsurface water content dynamics of these systems. This study examines ephemeral channels in the hyper-arid western Sonoran Desert, USA to determine how frequently water recharges the alluvial fill and identify variables that affect the depth and persistence of recharge. Precipitation, stream stage, and subsurface water content measurements were collected over a three-year study at six channels with varying contributing areas and thicknesses of alluvial fill. All channels contain coarse alluvium composed primarily of sands and gravels, and some locations also have localized layers of fine sediment at 2-3 m depth. Rain alone contributed 300-400 mm of water input to these channels over three years, but water content responses were only detected for 36% of the rain events at 10 cm depth, indicating that much of the rain water was either quickly evaporated or taken up by plants. Pulses of water from rain events were detected only in the top meter of alluvium. The sites each experienced ⩽5 brief flow events, which caused transient saturation that usually lasted only a few hours longer than flow. These events were the only apparent source of water to depths >1 m, and water from flow events quickly percolated past the deepest measurement depths (0.5-3 m). Sustained saturation in the shallow subsurface only developed where there was a near-surface layer of finer consolidated sediments that impeded deep percolation.

  6. How Temperature and Water levels affect Polar Mesospheric Cloud Formation

    NASA Astrophysics Data System (ADS)

    Smith, L. L.; Randall, C. E.; Harvey, V.

    2012-12-01

    Using the Cloud Imaging and Particle Size (CIPS) instrument data, which is part of the Aeronomy in the Mesosphere (AIM) mission, we compare the albedo and ice water content measurements of CIPS with the Navy Operation Global Atmospheric Prediction System - Advanced Level Phyiscs and High Altitude (NOGAPS-ALPHA) temperature and water vapor data in order to derive a greater understanding of cloud formation and physics. We particularly focus on data from June 2007 and July 2007 in this case study because of particular cloud structures and formations during this time period for future studies.

  7. International energy trade impacts on water resource crises: an embodied water flows perspective

    NASA Astrophysics Data System (ADS)

    Zhang, J. C.; Zhong, R.; Zhao, P.; Zhang, H. W.; Wang, Y.; Mao, G. Z.

    2016-07-01

    Water and energy are coupled in intimate ways (Siddiqi and Anadon 2011 Energy Policy 39 4529–40), which is amplified by international energy trade. The study shows that the total volume of energy related international embodied water flows averaged 6298 Mm3 yr‑1 from 1992–2010, which represents 10% of the water used for energy production including oil, coal, gas and electricity production. This study calculates embodied water import and export status of 219 countries from 1992 to 2010 and embodied water flow changes of seven regions over time (1992/2000/2010). In addition, the embodied water net export risk-crisis index and net embodied water import benefit index are established. According to the index system, 33 countries export vast amounts of water who have a water shortage, which causes water risk and crisis related to energy trade. While 29 countries abate this risk due to their rich water resource, 45 countries import embodied water linked to energy imports. Based on the different status of countries studied, the countries were classified into six groups with different policy recommendations.

  8. Efficacy of bedrock erosion by subglacial water flow

    NASA Astrophysics Data System (ADS)

    Beaud, F.; Flowers, G. E.; Venditti, J. G.

    2015-09-01

    Bedrock erosion by sediment-bearing subglacial water remains little-studied, however the process is thought to contribute to bedrock erosion rates in glaciated landscapes and is implicated in the excavation of tunnel valleys and the incision of inner gorges. We adapt physics-based models of fluvial abrasion to the subglacial environment, assembling the first model designed to quantify bedrock erosion caused by transient subglacial water flow. The subglacial drainage model consists of a one-dimensional network of cavities dynamically coupled to one or several Röthlisberger channels (R-channels). The bedrock erosion model is based on the tools and cover effect, whereby particles entrained by the flow impact exposed bedrock. We explore the dependency of glacial meltwater erosion on the structure and magnitude of water input to the system, the ice geometry and the sediment supply. We find that erosion is not a function of water discharge alone, but also depends on channel size, water pressure and on sediment supply, as in fluvial systems. Modelled glacial meltwater erosion rates are one to two orders of magnitude lower than the expected rates of total glacial erosion required to produce the sediment supply rates we impose, suggesting that glacial meltwater erosion is negligible at the basin scale. Nevertheless, due to the extreme localization of glacial meltwater erosion (at the base of R-channels), this process can carve bedrock (Nye) channels. In fact, our simulations suggest that the incision of bedrock channels several centimetres deep and a few meters wide can occur in a single year. Modelled incision rates indicate that subglacial water flow can gradually carve a tunnel valley and enhance the relief or even initiate the carving of an inner gorge.

  9. Using Gypsum to Affect Soil Erosion Processes and Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A driving force in soil erosion is the low electrolyte content of rain water. Various electrolyte sources have proven useful in serving as electrolyte sources such as phosphogypsum, lime and various salts, however, each has other potential problems. We performed a number of studies on low cost gypsu...

  10. CAN FLUORIDATION AFFECT WATER LEAD LEVELS AND LEAD NEUROTOXICITY?

    EPA Science Inventory

    Recent reports have attempted to show that certain approaches to fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of nexafluo...

  11. Preferred water flow and localised recharge in a variable regolith

    NASA Astrophysics Data System (ADS)

    Johnston, Colin D.

    1987-10-01

    The mechanisms of water flow and recharge to groundwater were investigated in a deep clayey regolith in southwest Western Australia. A 700 m 2 area was intensively studied for a period of two years. Vertical distributions of natural chloride in thirteen profiles up to 31 m deep were used to estimate the distribution of vertical soil-water flux density in the 16 m unsaturated zone and rates of recharge to groundwater. Groundwater dynamics were monitored using ten single and four multilevel piezometers. The regolith showed marked heterogeneity over horizontal and vertical distances of only a few metres. This resulted in complex patterns of water and solute movement through the profiles. Over most of the experimental area, vertical water flux density below 5 m in the unsaturated zone was from 2.2 to 7.2 mm yr -1. However, within a relatively small portion of the site, vertical soil-water flux density was 50-100 mm yr -1 throughout the unsaturated zone. This flux more closely matched the apparent rate of recharge to groundwater. The area of preferred flow is apparently due to a discontinuity within the regolith. A groundwater mound was seen to develop below the localised recharge area within 12-14 h of intense rainstorms, and then dissipated over a period of 2-4 days.

  12. Modelling water flow under glaciers and ice sheets

    PubMed Central

    Flowers, Gwenn E.

    2015-01-01

    Recent observations of dynamic water systems beneath the Greenland and Antarctic ice sheets have sparked renewed interest in modelling subglacial drainage. The foundations of today's models were laid decades ago, inspired by measurements from mountain glaciers, discovery of the modern ice streams and the study of landscapes evacuated by former ice sheets. Models have progressed from strict adherence to the principles of groundwater flow, to the incorporation of flow ‘elements’ specific to the subglacial environment, to sophisticated two-dimensional representations of interacting distributed and channelized drainage. Although presently in a state of rapid development, subglacial drainage models, when coupled to models of ice flow, are now able to reproduce many of the canonical phenomena that characterize this coupled system. Model calibration remains generally out of reach, whereas widespread application of these models to large problems and real geometries awaits the next level of development. PMID:27547082

  13. 43 CFR 404.57 - Does this rule have any affect on state water law?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Does this rule have any affect on state water law? 404.57 Section 404.57 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR RECLAMATION RURAL WATER SUPPLY PROGRAM Miscellaneous § 404.57 Does this rule have any affect on state...

  14. 43 CFR 404.57 - Does this rule have any affect on state water law?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Does this rule have any affect on state water law? 404.57 Section 404.57 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR RECLAMATION RURAL WATER SUPPLY PROGRAM Miscellaneous § 404.57 Does this rule have any affect on state...

  15. Hydrology and geochemistry of a slag-affected aquifer and chemical characteristics of slag-affected ground water, northwestern Indiana and northeastern Illinois

    USGS Publications Warehouse

    Bayless, E. Randall; Greeman, T.K.; Harvey, C.C.

    1998-01-01

    ?aquifer interface. The solid-phase analyses indicated that calcite, dolomite, and quartz generally were present throughout the slag?aquifer system; barian celestite, cristobalite, manganese-bearing calcite, and minrecordite were present in fewer samples. Trace elements that are liberated from the slag may be incorporated as impurities during precipitation of major minerals, sorbed onto clays and other grainsize fractions not analyzed as part of this study, or present in low-abundance minerals that were not detected by the X-ray analysis. Mass-balance and speciation programs were used to identify geochemical processes that may be occurring as water infiltrates through the slag, flows into the aquifer, and discharges into Lake George. The geochemical models indicate that precipitation of calcite may be occurring where slag-affected water enters the aquifer. Models also indicate that dolomite precipitation and clay-mineral dissolution may be occurring at the slag?aquifer interface; however, dolomite precipitation is generally believed to require geologically long time periods. Silica may be dissolving where slag-affected ground water enters the aquifer and may be precipitating where slag-affected ground water discharges to the lakebed of Lake George. In addition to the site-specific study, a statistical analysis of regional water quality was done to compare ground water in wells affected and unaffected by slag. When com-pared to wells in background locations in the Calumet aquifer, wells screened in slag across northwestern Indiana and northeastern Illinois generally had relatively higher pH and specific-conductance values and relatively higher concentrations of alkalinity, dissolved solids, suspended solids, total organic carbon, calcium, potassium, sodium, chloride, aluminum, barium, and possibly magnesium, sulfate, chromium, cobalt, copper, cyanide, manganese, mercury, nickel, and vanadium. When compared to wells in slag and wells in background locations, ground water from immediat

  16. Human modification of global water vapor flows from the land surface

    NASA Astrophysics Data System (ADS)

    Gordon, Line J.; Steffen, Will; Jönsson, Bror F.; Folke, Carl; Falkenmark, Malin; Johannessen, Åse

    2005-05-01

    It is well documented that human modification of the hydrological cycle has profoundly affected the flow of liquid water across the Earth's land surface. Alteration of water vapor flows through land-use changes has received comparatively less attention, despite compelling evidence that such alteration can influence the functioning of the Earth System. We show that deforestation is as large a driving force as irrigation in terms of changes in the hydrological cycle. Deforestation has decreased global vapor flows from land by 4% (3,000 km3/yr), a decrease that is quantitatively as large as the increased vapor flow caused by irrigation (2,600 km3/yr). Although the net change in global vapor flows is close to zero, the spatial distributions of deforestation and irrigation are different, leading to major regional transformations of vapor-flow patterns. We analyze these changes in the light of future land-use-change projections that suggest widespread deforestation in sub-Saharan Africa and intensification of agricultural production in the Asian monsoon region. Furthermore, significant modification of vapor flows in the lands around the Indian Ocean basin will increase the risk for changes in the behavior of the Asian monsoon system. This analysis suggests that the need to increase food production in one region may affect the capability to increase food production in another. At the scale of the Earth as a whole, our results emphasize the need for climate models to take land-use change, in both land cover and irrigation, into account. deforestation | irrigation | land-use changes | climate change | evapotranspiration

  17. Water flow through carbon nanotube junctions as molecular convergent nozzles

    NASA Astrophysics Data System (ADS)

    Hanasaki, Itsuo; Nakatani, Akihiro

    2006-06-01

    Molecular dynamics (MD) simulations are conducted for water flow through carbon nanotube (CNT) junctions as molecular nozzles. The fluidized piston model (FPM) is employed to drive the inlet flow at streaming velocities of 25 and 50 m s-1. Water flow through the CNT junctions is found to undergo an increase in streaming velocity, a decrease in pressure, and an increase in temperature. Although the difference of the upstream velocities does not generally lead to an appreciable density difference in the downstream CNT, the higher streaming velocity causes the upstream density to increase. The streaming velocity remains almost constant in the upstream CNT, but increases dramatically in the junction region. The ratio of downstream to upstream streaming velocities increases with the ratio of upstream to downstream cross section. A higher inlet velocity results in larger acceleration, which is generally more noticeable at larger cross-sectional ratios, and less prominent in junctions with smaller cross-sectional ratios. The cross-sectional ratio calculated from the internal radii of the CNTs based on the oxygen atomic density profile of water is closer to the ratio of downstream to upstream streaming velocities than the cross-sectional ratio calculated from the radii given by the carbon atomic centres.

  18. Factors affecting atrazine concentration and quantitative determination in chlorinated water.

    PubMed

    Wulfeck-Kleier, Karen A; Ybarra, Michael D; Speth, Thomas F; Magnuson, Matthew L

    2010-01-29

    Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be observed. Some transformation products detected through the use of high performance liquid chromatography-electrospray mass spectrometry are consistent with the formation of N-chloro atrazine. The effects of applied chlorine, pH, and reaction time on the transformation reaction were studied to help understand the practical implications of the transformation on the accurate determination of atrazine in drinking waters. The errors in the determination of atrazine are a function of the type of dechlorinating agent applied during sample preparation and the analytical instrumentation utilized. When a reductive dechlorinating agent, such as sodium sulfite or ascorbic acid is used, the quantification of the atrazine can be inaccurate, ranging from 2-fold at pH 7.5 to 30-fold at pH 6.0. The results suggest HPLC/UV and ammonium chloride quenching may be best for accurate quantification. Hence, the results also appear to have implications for both compliance monitoring and health effects studies that utilize gas chromatography analysis with sodium sulfite or ascorbic acid as the quenching agent. PMID:20022012

  19. Numerical study of different bottom boundary conditions on water flow in lysimeters

    NASA Astrophysics Data System (ADS)

    Groh, Jannis; Vanderborght, Jan; Pütz, Thomas; Vereecken, Harry

    2015-04-01

    The separation of the bottom of the lysimeter from its surroundings in the field introduces an artificial boundary that may impact the water balance of lysimeters. The use of tension controlled lysimeter (TCL) prevents an artificial boundary at the end of the lysimeter. Water flow across the lysimeter bottom can be controlled by the adjustment of matric potentials at the lower end of the lysimeter to measured field conditions in the close vicinity of the facility. However lysimeters are often transferred from the place where the soil monoliths were sampled to another location for practical reasons or to study the effect of climate change (e.g. SOILCan). The water flux across the bottom boundary of translocated TCL can be affected if climatic conditions, soil properties and the hydrogeological setting in the field differ from the place where the lysimeter was taken from. To assess the potential impact of different bottom boundary conditions on the water balance of translocated TCL a numerical study in virtual soils was conducted. We present a comparison of different approaches using water balance simulations. Results shows that water balance components of translocated TCL are sensitive towards the soil hydraulic parameters and hydrogeological setting in the field. The change in field conditions can impact the water flux dynamic across the lysimeter bottom, change the evaporation and the plant water uptake and release. A shift in the climate regime (translocation) will modify the depth and dynamics of the water table and impact the water balance of lysimeters.

  20. Mathematical modelling of surface water-groundwater flow and salinity interactions in the coastal zone

    NASA Astrophysics Data System (ADS)

    Spanoudaki, Katerina; Kampanis, Nikolaos A.

    2014-05-01

    Coastal areas are the most densely-populated areas in the world. Consequently water demand is high, posing great pressure on fresh water resources. Climatic change and its direct impacts on meteorological variables (e.g. precipitation) and indirect impact on sea level rise, as well as anthropogenic pressures (e.g. groundwater abstraction), are strong drivers causing groundwater salinisation and subsequently affecting coastal wetlands salinity with adverse effects on the corresponding ecosystems. Coastal zones are a difficult hydrologic environment to represent with a mathematical model due to the large number of contributing hydrologic processes and variable-density flow conditions. Simulation of sea level rise and tidal effects on aquifer salinisation and accurate prediction of interactions between coastal waters, groundwater and neighbouring wetlands requires the use of integrated surface water-groundwater models. In the past few decades several computer codes have been developed to simulate coupled surface and groundwater flow. In these numerical models surface water flow is usually described by the 1-D Saint Venant equations (e.g. Swain and Wexler, 1996) or the 2D shallow water equations (e.g. Liang et al., 2007). Further simplified equations, such as the diffusion and kinematic wave approximations to the Saint Venant equations, are also employed for the description of 2D overland flow and 1D stream flow (e.g. Gunduz and Aral, 2005). However, for coastal bays, estuaries and wetlands it is often desirable to solve the 3D shallow water equations to simulate surface water flow. This is the case e.g. for wind-driven flows or density-stratified flows. Furthermore, most integrated models are based on the assumption of constant fluid density and therefore their applicability to coastal regions is questionable. Thus, most of the existing codes are not well-suited to represent surface water-groundwater interactions in coastal areas. To this end, the 3D integrated

  1. Catchment travel time distributions and water flow in soils

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.; Beven, K. J.; Bertuzzo, E.; Nicotina, L.; Davies, J.; Fiori, A.; Russo, D.; Botter, G.

    2011-07-01

    Many details about the flow of water in soils in a hillslope are unknowable given current technologies. One way of learning about the bulk effects of water velocity distributions on hillslopes is through the use of tracers. However, this paper will demonstrate that the interpretation of tracer information needs to become more sophisticated. The paper reviews, and complements with mathematical arguments and specific examples, theory and practice of the distribution(s) of the times water particles injected through rainfall spend traveling through a catchment up to a control section (i.e., "catchment" travel times). The relevance of the work is perceived to lie in the importance of the characterization of travel time distributions as fundamental descriptors of catchment water storage, flow pathway heterogeneity, sources of water in a catchment, and the chemistry of water flows through the control section. The paper aims to correct some common misconceptions used in analyses of travel time distributions. In particular, it stresses the conceptual and practical differences between the travel time distribution conditional on a given injection time (needed for rainfall-runoff transformations) and that conditional on a given sampling time at the outlet (as provided by isotopic dating techniques or tracer measurements), jointly with the differences of both with the residence time distributions of water particles in storage within the catchment at any time. These differences are defined precisely here, either through the results of different models or theoretically by using an extension of a classic theorem of dynamic controls. Specifically, we address different model results to highlight the features of travel times seen from different assumptions, in this case, exact solutions to a lumped model and numerical solutions of the 3-D flow and transport equations in variably saturated, physically heterogeneous catchment domains. Our results stress the individual characters of the

  2. Water chemistry and ecotoxicity of an acid mine drainage-affected stream in subtropical China during a major flood event.

    PubMed

    Lin, C; Wu, Y; Lu, W; Chen, A; Liu, Y

    2007-04-01

    Field and laboratory work was carried out to investigate the chemistry and ecotoxicity of stream water affected by acid mine drainage in a tributary catchment of the Pearl River in subtropical China during a major flood that corresponded to a return period of 100 years. The results indicate that stream water was affected by acid mine drainage from the Dabaoshan mine at least to a distance of 25 km downstream of the mine water discharge point. It appears that H(+) generated from sulfide oxidation in the waste rock dumps was readily available for exporting. The amount of H(+) being discharged into the receiving stream depended on the volume of out-flowing waters. However, there was a lag time for the discharges of the metals. This may be attributed to the slower release of metals, relative to H(+), because it might take more time for the dissolution of heavy metal-bearing compounds, particularly the sparsely soluble jarosites. Fe, Zn and Al were the major metals of potential toxicity contained in the AMD-affected stream water, followed by Mn, Cu, Pb, As, Cd and Ni. The concentrations of these metals in the water decreased rapidly down the stream. This corresponds with an increase in the concentrations of reactive heavy metal fractions in benthic mud down the stream, reflecting the precipitation of heavy metal compounds with increasing pH and their subsequent deposition in the streambed. Toxicity tests show that the AMD-affected stream water at 3.5 km downstream of the discharge point was highly toxic to the test organism. At 25 km downstream of the discharge point where stream water pH was as high as 5.75, marked toxic responses of the test organism were still observed. PMID:16979817

  3. Sculpting of an erodible body by flowing water.

    PubMed

    Ristroph, Leif; Moore, Matthew N J; Childress, Stephen; Shelley, Michael J; Zhang, Jun

    2012-11-27

    Erosion by flowing fluids carves striking landforms on Earth and also provides important clues to the past and present environments of other worlds. In these processes, solid boundaries both influence and are shaped by the surrounding fluid, but the emergence of morphology as a result of this interaction is not well understood. We study the coevolution of shape and flow in the context of erodible bodies molded from clay and immersed in a fast, unidirectional water flow. Although commonly viewed as a smoothing process, we find that erosion sculpts pointed and cornerlike features that persist as the solid shrinks. We explain these observations using flow visualization and a fluid mechanical model in which the surface shear stress dictates the rate of material removal. Experiments and simulations show that this interaction ultimately leads to self-similarly receding boundaries and a unique front surface characterized by nearly uniform shear stress. This tendency toward conformity of stress offers a principle for understanding erosion in more complex geometries and flows, such as those present in nature. PMID:23150552

  4. Early regimes of water capillary flow in slit silica nanochannels.

    PubMed

    Oyarzua, Elton; Walther, Jens H; Mejía, Andrés; Zambrano, Harvey A

    2015-06-14

    Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibition of water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopic confinement, initial conditions of liquid uptake and air pressurization on the dynamics of capillary filling. The results indicate that the nanoscale imbibition process is divided into three main flow regimes: an initial regime where the capillary force is balanced only by the inertial drag and characterized by a constant velocity and a plug flow profile. In this regime, the meniscus formation process plays a central role in the imbibition rate. Thereafter, a transitional regime takes place, in which, the force balance has significant contributions from both inertia and viscous friction. Subsequently, a regime wherein viscous forces dominate the capillary force balance is attained. Flow velocity profiles identify the passage from an inviscid flow to a developing Poiseuille flow. Gas density profiles ahead of the capillary front indicate a transient accumulation of air on the advancing meniscus. Furthermore, slower capillary filling rates computed for higher air pressures reveal a significant retarding effect of the gas displaced by the advancing meniscus. PMID:25976034

  5. Effect of electric charging on the velocity of water flow in CNT.

    PubMed

    Abbasi, Hossein Reza; Karimian, S M Hossein

    2016-09-01

    The role of electrical charge in controlling the velocity of water molecules in a finite single-walled carbon nanotube (CNT) was studied in detail using molecular dynamics simulation. Different test cases were examined to determine the parameters affecting the control of water-flow velocity in CNT upon electrically charging the surface of a CNT. The results showed that charge magnitude and volume, as well as the charging scenario, are the parameters having greatest effect. The implementation of electric charge on the surface of a CNT was demonstrated to decrease the resistance of CNT to incoming water flow at the entrance, but to increase friction-type resistance to flow along the CNT. Therefore, through controlling the magnitude of electric charge, water flow through the CNT may be accelerated, or decelerated. The results show that the velocity of molecular flow in the CNT increases to a maximum value, and then decreases with electric charge regardless of its sign. In the case studied here, this maximum velocity occurs at electric charging of ±0.25e/atom. It was also shown that, to reach similar flow velocities in a CNT, it is not sufficient to merely implement equal volumes of electric charge, where the volume of electric charging is defined as charge magnitude × charging time. In fact , both magnitude of charging and volume of electric charging must be equal to each other. These findings, together with options to implement scenarios with alternative charging, provide the means to effectively adjust desired velocities in a CNT. PMID:27488104

  6. Arsenic removal from flowing irrigation water in bangladesh: impacts of channel properties.

    PubMed

    Lineberger, Ethan M; Badruzzaman, A Borhan M; Ali, M Ashraf; Polizzotto, Matthew L

    2013-11-01

    Across Bangladesh, dry-season irrigation with arsenic-contaminated well water is loading arsenic onto rice paddies, leading to increased arsenic concentrations in plants, diminished crop yields, and increased human health risks. As irrigation water flows through conveyance channels between wells and rice fields, arsenic concentrations change over space and time, indicating that channels may provide a location for removing arsenic from solution. However, few studies have systematically evaluated the processes controlling arsenic concentrations in irrigation channels, limiting the ability to manipulate these systems and enhance arsenic removal from solution. The central goal of this study was to quantify how channel design affected removal of dissolved arsenic from flowing irrigation water. Field experiments were conducted in Bangladesh using a chemically constant source of arsenic-contaminated irrigation water and an array of constructed channels with varying geometries. The resulting hydraulic conditions affected the quantity of arsenic removed from solution within the channels by promoting known hydrogeochemical processes. Channels three times the width of control channels removed ∼3 times the mass of arsenic over 32 min of flowing conditions, whereas negligible arsenic removal was observed in tarp-lined channels, which prevented soil-water contact. Arsenic removal from solution was ∼7 times higher in a winding, 200-m-long channel than in the straight, 45-m-long control channels. Arsenic concentrations were governed by oxidative iron-arsenic coprecipitation within the water column, sorption to soils, and phosphate competition. Collectively, these results suggest that better design and management of irrigation channels may play a part in arsenic mitigation strategies for rice fields in Southern Asia. PMID:25602413

  7. Evidence suggests water once flowed vigorously on Mars

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-10-01

    "In some cases, when you do geology, a picture is worth 1000 words," Mars Science Laboratory project scientist John Grotzinger said at a 27 September news briefing to announce that imagery taken by a camera onboard NASA's Mars Curiosity rover shows evidence that water once flowed vigorously in a region on the surface of Mars. One of the pictured rock outcrops, about 10-15 centimeters thick and named Hottah after Canada's Hottah lake, "looked like somebody came along the surface of Mars with a jackhammer and lifted up a sidewalk that you might see in downtown LA in sort of a construction site," said Grotzinger, who is with the California Institute of Technology in Pasadena. "This is a rock that was formed in the presence of water, and we can characterize that water as being a vigorous flow on the surface of Mars," he said. "We were really excited about this because this is one of the reasons we were interested in coming to this landing site, because it presented from orbit quite a strong case that we would find evidence for water on the ground."

  8. On spurious water flow during numerical simulation of steam injection into water-saturated soil.

    PubMed

    Gudbjerg, J; Trötschler, O; Färber, A; Sonnenborg, T O; Jensen, K H

    2004-12-01

    Numerical simulation of steam injection into a water-saturated porous medium may be hindered by unphysical behavior causing the model to slow down. We show how spurious water flow may arise on the boundary between a steam zone and a saturated zone, giving rise to dramatic pressure drops. This is caused by the discretization of the temperature gradient coupled with the direct relation between pressure and temperature in the steam zone. The problem may be a severe limitation to numerical modeling. A solution is presented where the spurious water flow is blocked and this widely enhances the performance of the model. This new method is applied to a previously reported example exhibiting numerical problems. Furthermore, it is applied to the simulation of 2-D sandbox experiments where LNAPL is remediated from a smearing zone by steam injection. These experiments would have been difficult to analyze numerically without the adjustment to prevent spurious flow. PMID:15610904

  9. Experimental and numerical simulations of heat transfers between flowing water and a frozen porous medium

    NASA Astrophysics Data System (ADS)

    Roux, Nicolas; Grenier, Christophe; Costard, François

    2015-04-01

    In permafrost-affected regions, hydrological changes due to global warming are still under investigation. But yet, we can already foresee from recent studies that for example, the variability and intensity of surface/subsurface flow are likely to be affected by permafrost degradation. The feedback induced by such changes on permafrost degradation is still not clearly assessed. Of particular interest are lake and river's taliks. A talik is a permanently unfrozen zone that lies below rivers or lakes. They are likely to play a key role in the formerly presented interactions, given that they are the only paths for groundwater flow in permafrost regions. Thus heat transfers on a regional scale are influenced by groundwater circulation. The aim of our study is therefore to investigate the evolution of river's taliks. In addition, they are the only perennial liquid water resources in continuous permafrost environments. The issue associated is to what extent can taliks develop into the future because of climate change and how likely are they to become open taliks, connecting sub-permafrost water with surface water with potentially strong geochemical changes? We developed a multidisciplinary approach coupling field investigation, experimental studies in a cold room and numerical modeling. The field investigation concerns Central Yakutia, Siberia, where we have installed instruments to monitor ground temperatures and water pressure in a small river's talik between two thermokarst lakes. We present here the results corresponding to the cold room experimental work, associating numerical modeling and laboratory experiments in order to look after the main parameters controlling river's talik installation and validate our numerical simulation approach. In a cold room at GEOPS, where a metric scale channel is filled with a porous medium (sand or silty-clay), we are able to control air, water and permafrost initial temperature, but also water flow. At initial time, the "river

  10. Ground-Water Flow, 2004-07, and Water Quality, 1992-2007, in McBaine Bottoms, Columbia, Missouri

    USGS Publications Warehouse

    Smith, Brenda Joyce; Richards, Joseph M.

    2008-01-01

    The U.S. Geological Survey, in cooperation with the city of Columbia, Missouri, and the Missouri Department of Conservation, collected ground-water quality data, surface-water quality data, and water-level data in McBaine Bottoms, southwest of Columbia. McBaine Bottoms, adjacent to the Missouri River, is the location of the municipal-supply well field for the city of Columbia, the city of Columbia wastewater-treatment wetlands, and the Missouri Department of Conservation Eagle Bluffs Conservation Area. This report describes the ground-water flow and water quality of McBaine Bottoms and provides information to better understand the interaction between treated effluent from the wetlands used on the Eagle Bluffs Conservation Area and the water in the alluvial aquifer that is pumped from the city of Columbia municipal-supply well field. Changes in major chemical constituent concentrations have been detected at several sampling sites between pre- and post-effluent application data. Analysis of post-effluent data indicates substantial changes in calcium, potassium, sodium, chloride, and sulfate concentrations in ground water. These changes became apparent shortly after the beginning of the operation of the wastewater-treatment wetland in 1994 and the formation of the Eagle Bluffs Conservation Area, which uses the treated effluent as a water source for the management of migratory water fowl. The changes have continued throughout the 15 years of sample collection. The concentrations of these major chemical constituents are on the mixing continuum between pre-effluent ground water as one end member and the treated wastewater effluent as the other end member. For monitoring wells that had changes in major chemical constituent concentrations, the relative percentage of treated effluent in the ground water, assuming chloride is conservative, ranged from 6 to 88 percent. Twenty-two monitoring wells throughout McBaine Bottoms have been affected by effluent based on chloride

  11. Issues affecting advanced passive light-water reactor safety analysis

    SciTech Connect

    Beelman, R.J.; Fletcher, C.D.; Modro, S.M.

    1992-08-01

    Next generation commercial reactor designs emphasize enhanced safety through improved safety system reliability and performance by means of system simplification and reliance on immutable natural forces for system operation. Simulating the performance of these safety systems will be central to analytical safety evaluation of advanced passive reactor designs. Yet the characteristically small driving forces of these safety systems pose challenging computational problems to current thermal-hydraulic systems analysis codes. Additionally, the safety systems generally interact closely with one another, requiring accurate, integrated simulation of the nuclear steam supply system, engineered safeguards and containment. Furthermore, numerical safety analysis of these advanced passive reactor designs wig necessitate simulation of long-duration, slowly-developing transients compared with current reactor designs. The composite effects of small computational inaccuracies on induced system interactions and perturbations over long periods may well lead to predicted results which are significantly different than would otherwise be expected or might actually occur. Comparisons between the engineered safety features of competing US advanced light water reactor designs and analogous present day reactor designs are examined relative to the adequacy of existing thermal-hydraulic safety codes in predicting the mechanisms of passive safety. Areas where existing codes might require modification, extension or assessment relative to passive safety designs are identified. Conclusions concerning the applicability of these codes to advanced passive light water reactor safety analysis are presented.

  12. Issues affecting advanced passive light-water reactor safety analysis

    SciTech Connect

    Beelman, R.J.; Fletcher, C.D.; Modro, S.M.

    1992-01-01

    Next generation commercial reactor designs emphasize enhanced safety through improved safety system reliability and performance by means of system simplification and reliance on immutable natural forces for system operation. Simulating the performance of these safety systems will be central to analytical safety evaluation of advanced passive reactor designs. Yet the characteristically small driving forces of these safety systems pose challenging computational problems to current thermal-hydraulic systems analysis codes. Additionally, the safety systems generally interact closely with one another, requiring accurate, integrated simulation of the nuclear steam supply system, engineered safeguards and containment. Furthermore, numerical safety analysis of these advanced passive reactor designs wig necessitate simulation of long-duration, slowly-developing transients compared with current reactor designs. The composite effects of small computational inaccuracies on induced system interactions and perturbations over long periods may well lead to predicted results which are significantly different than would otherwise be expected or might actually occur. Comparisons between the engineered safety features of competing US advanced light water reactor designs and analogous present day reactor designs are examined relative to the adequacy of existing thermal-hydraulic safety codes in predicting the mechanisms of passive safety. Areas where existing codes might require modification, extension or assessment relative to passive safety designs are identified. Conclusions concerning the applicability of these codes to advanced passive light water reactor safety analysis are presented.

  13. The Influence of Impurities in a Water Solution with Drag Reducing Surfactants on the Flow Drag-Reduction and a Recovering Method of Its Decreased Drag Reduction Effect.

    NASA Astrophysics Data System (ADS)

    Nakata, Toru; Sato, Kenji; Inaba, Hideo; Horibe, Akihiko; Haruki, Naoto

    The drag reduction of a water flow with new drag reducing surfactants (amine oxide type nonionic surfactants, mixtures of amine oxide type nonionic surfactants and betaine type amphoteric surfactants) which were selected as environmentally acceptable drag reducing additives was investigated experimentally. Addition of amine oxide type nonionic surfactants to hot or cold water can reduce flow drag in a turbulent pipe flow. The present research investigated how various ionic components dissolved in water affected this drag reducing effect. It was found that ionic impurities contained in the water affected the pipe flow drag reducing effect by amine oxide type nonionic surfactants. Moreover, it was clarified that the decrease in the pipe flow drag reducing effect was recovered by adding a mixture of amine oxide type nonionic surfactants and betaine type amphoteric surfactant to the water with ionic impurities.

  14. Computer programs for modeling flow and water quality of surface water systems

    USGS Publications Warehouse

    Lorens, J.A.

    1982-01-01

    A selection of available computer programs for modeling flow and water quality in surface water systems is described. The models include programs developed as part of the U.S. Geological Survey Water Resources Division hydrologic research activities and others developed by other agencies, universities, and consulting firms. Each model description includes a statement of program use; data requirements; computer costs; availability of documentation and reference material; and a contact person for additional information. The report is intended to assist the researcher by presenting a very brief description of the surface-water models which are readily available for project use. (USGS)

  15. Quantitative dye-tracing of karst ground-water flow

    USGS Publications Warehouse

    Smoot, James; Mull, Donald; Liebermann, Timothy

    1989-01-01

    Analysis of the results of repeat quantitative dye traces between a sinkhole and a spring used for public water supply were used to describe predictive relations between discharge, mean travel time, apparent ground-water flow velocity and solute transport characteristics. Normalized peak concentration, mean travel time, and standard deviation of travel times were used to produce a dimensionless, composite type curve that was used to produce a dimensionless, composite type curve that was used to simulate solute transport characteristics for selected discharges. Using this curve and previously developed statistical relations, a water manager can estimate the arrival time, peak concentration, and persistence of a soluble contaminant at a supply spring or well based on discharge and the quantity of spilled contaminant.

  16. Parsimonious modelling of water and suspended sediment flux from nested catchments affected by selective tropical forestry.

    PubMed Central

    Chappell, N A; McKenna, P; Bidin, K; Douglas, I; Walsh, R P

    1999-01-01

    The ability to model the suspended sediment flux (SSflux) and associated water flow from terrain affected by selective logging is important to the establishment of credible measures to improve the ecological sustainability of forestry practices. Recent appreciation of the impact of parameter uncertainty on the statistical credibility of complex models with little internal state validation supports the use of more parsimonious approaches such as data-based mechanistic (DBM) modelling. The DBM approach combines physically based understanding with model structure identification based on transfer functions and objective statistical inference. Within this study, these approaches have been newly applied to rainfall-SSflux response. The dynamics of the sediment system, together with the rainfall-river flow system, were monitored at five nested contributory areas within a 44 ha headwater region in Malaysian Borneo. The data series analysed covered a whole year at a 5 min resolution, and were collected during a period some five to six years after selective timber harvesting had ceased. Physically based and statistical interpretation of these data was possible given the wealth of contemporary and past hydrogeomorphic data collected within the same region. The results indicated that parsimonious, three-parameter models of rainfall-river flow and rainfall-SSflux for the whole catchment describe 80 and 90% of the variance, respectively, and that parameter changes between scales could be explained in physically meaningful terms. Indeed, the modelling indicated some new conceptual descriptions of the river flow and sediment-generation systems. An extreme rainstorm having a 10-20 year return period was present within the data series and was shown to generate new mass movements along the forestry roads that had a differential impact on the monitored contributory areas. Critically, this spatially discrete behaviour was captured by the modelling and may indicate the potential use of

  17. Water flow and nitrate transport through a lakeshore with different revetment materials

    NASA Astrophysics Data System (ADS)

    Li, Yong; Šimůnek, Jirka; Zhang, Zhentin; Huang, Manli; Ni, Lixiao; Zhu, Liang; Hua, Jianlan; Chen, Yong

    2015-01-01

    As an important part of a transition zone surrounding a lake, lakeshore plays a critical role in connecting hydrology and biochemistry between surface water and groundwater. The shape, slope, subsurface features, and seepage face of a lakeside slope have been reported to affect water and nutrient exchange and consequently the water quality of near-shore lake water. Soil tank experiments and Hydrus-2D model simulations were conducted to improve our understanding of the influence of slope revetment materials (SRMs) on water flow and solute transport in a lakeshore zone. The low hydraulic conductivity of SRMs affected flow patterns in the lakeshore zone and resulted in a local increase of the groundwater table near the slope face. Water and solute flux distributions on the slope face under bare-slope conditions followed an exponential function. Fluxes were concentrated within a narrow portion of the slope surface near the intersection point between the lake water level and the slope face. Surface pollutants (for example from fishponds and paddy fields surrounding a lake) were transported into the lake along shallow groundwater through both unsaturated and saturated zones. The SRMs on the slope face affected the ratio of water and solute fluxes in the unsaturated zone, increasing along with the decline of the hydraulic conductivity of SRMs. Furthermore, as the hydraulic conductivity of SRMs decreased, the retention time and the potential for oxygen reduction correspondingly increased, which affected the nitrogen transport and transformations in the lakeshore zone. Simulated and experimental results indicate that if concrete along the shoreline of Lake Taihu is replaced with a relatively high-conductivity lime or the slope is left bare, water fluxes will increase less than solute fluxes, which will rise significantly, in particular in the unsaturated zone and along the seepage face. On the other hand, the largest water and solute fluxes along the shoreline for the bare

  18. Enhanced Geothermal Systems Research and Development: Models of Subsurface Chemical Processes Affecting Fluid Flow

    SciTech Connect

    Moller, Nancy; Weare J. H.

    2008-05-29

    Successful exploitation of the vast amount of heat stored beneath the earth’s surface in hydrothermal and fluid-limited, low permeability geothermal resources would greatly expand the Nation’s domestic energy inventory and thereby promote a more secure energy supply, a stronger economy and a cleaner environment. However, a major factor limiting the expanded development of current hydrothermal resources as well as the production of enhanced geothermal systems (EGS) is insufficient knowledge about the chemical processes controlling subsurface fluid flow. With funding from past grants from the DOE geothermal program and other agencies, we successfully developed advanced equation of state (EOS) and simulation technologies that accurately describe the chemistry of geothermal reservoirs and energy production processes via their free energies for wide XTP ranges. Using the specific interaction equations of Pitzer, we showed that our TEQUIL chemical models can correctly simulate behavior (e.g., mineral scaling and saturation ratios, gas break out, brine mixing effects, down hole temperatures and fluid chemical composition, spent brine incompatibilities) within the compositional range (Na-K-Ca-Cl-SO4-CO3-H2O-SiO2-CO2(g)) and temperature range (T < 350°C) associated with many current geothermal energy production sites that produce brines with temperatures below the critical point of water. The goal of research carried out under DOE grant DE-FG36-04GO14300 (10/1/2004-12/31/2007) was to expand the compositional range of our Pitzer-based TEQUIL fluid/rock interaction models to include the important aluminum and silica interactions (T < 350°C). Aluminum is the third most abundant element in the earth’s crust; and, as a constituent of aluminosilicate minerals, it is found in two thirds of the minerals in the earth’s crust. The ability to accurately characterize effects of temperature, fluid mixing and interactions between major rock-forming minerals and hydrothermal and

  19. Ground-water levels, predevelopment ground-water flow, and stream-aquifer relations in the vicinity of the Savannah River Site, Georgia and South Carolina

    USGS Publications Warehouse

    Clarke, John S.; West, Christopher T.

    1998-01-01

    Ground-water levels, predevelopment ground-water flow, and stream-aquifer relations in the vicinity of the U.S. Department of Energy Savannah River Site, Georgia and South Carolina, were evaluated as part of a cooperative study between the U.S. Geological Survey, U.S. Department of Energy, and Georgia Department of Natural Resources. As part of this evaluation: (1) ground-water-level fluctuations and trends in three aquifer systems in sediment of Cretaceous and Tertiary age were described and related to patterns of ground-water use and precipitations; (2) a conceptual model ofthe stream-aquifer flow system was developed; (3) the predevelopment ground-water flow system, configuration of potentiometric surfaces, trans-river flow, and recharge-discharge relations were described; and (4) stream-aquifer relations and the influence of river incision on ground-water flow and stream-aquifer relations were described. The 5,147-square mile study area is located in the northern part of the Coastal Plain physiographic province of Georgia and South Carolina. Coastal Plain sediments comprise three aquifer systems consisting of seven aquifers that are separated hydraulically by confining units. The aquifer systems are, in descending order: (1) the Floridan aquifer system?consisting of the Upper Three Runs and Gordon aquifers in sediments of Eocene age; (2) the Dublin aquifer system?consisting of the Millers Pond, upper Dublin, and lower Dublin aquifers in sediments of Paleocene-Late Cretaceous age; and (3) the Midville aquifer system?consisting of the upper Midville and lower Midville aquifers in sediments of Late Cretaceous age. The Upper Three Runs aquifer is the shallowest aquifer and is unconfined to semi-confined throughout most of the study area. Ground-water levels in the Upper Three Runs aquifer respond to a local flow system and are affected mostly by topography and climate. Ground-water flow in the deeper, Gordon aquifer and Dublin and Midville aquifer systems is

  20. Explore the Impacts of River Flow and Water Quality on Fish Communities

    NASA Astrophysics Data System (ADS)

    Tsai, W. P.; Chang, F. J.; Lin, C. Y.; Hu, J. H.; Yu, C. J.; Chu, T. J.

    2015-12-01

    Owing to the limitation of geographical environment in Taiwan, the uneven temporal and spatial distribution of rainfall would cause significant impacts on river ecosystems. To pursue sustainable water resources development, integrity and rationality is important to water management planning. The water quality and the flow regimes of rivers are closely related to each other and affect river ecosystems simultaneously. Therefore, this study collects long-term observational heterogeneity data, which includes water quality parameters, stream flow and fish species in the Danshui River of norther Taiwan, and aims to explore the complex impacts of water quality and flow regime on fish communities in order to comprehend the situations of the eco-hydrological system in this river basin. First, this study improves the understanding of the relationship between water quality parameters, flow regime and fish species by using artificial neural networks (ANNs). The Self-organizing feature map (SOM) is an unsupervised learning process used to cluster, analyze and visualize a large number of data. The results of SOM show that nine clusters (3x3) forms the optimum map size based on the local minimum values of both quantization error (QE) and topographic error (TE). Second, the fish diversity indexes are estimated by using the Adapted network-based fuzzy inference system (ANFIS) based on key input factors determined by the Gamma Test (GT), which is a useful tool for reducing model dimension and the structure complexity of ANNs. The result reveals that the constructed models can effectively estimate fish diversity indexes and produce good estimation performance based on the 9 clusters identified by the SOM, in which RMSE is 0.18 and CE is 0.84 for the training data set while RMSE is 0.20 and CE is 0.80 for the testing data set.

  1. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the height of the diurnal high water at a particular location measured over a lunar cycle of 19 years. ...; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and....34 Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high...

  2. Hydro-dynamic damping theory in flowing water

    NASA Astrophysics Data System (ADS)

    Monette, C.; Nennemann, B.; Seeley, C.; Coutu, A.; Marmont, H.

    2014-03-01

    Fluid-structure interaction (FSI) has a major impact on the dynamic response of the structural components of hydroelectric turbines. On mid-head to high-head Francis runners, the rotor-stator interaction (RSI) phenomenon always has to be considered carefully during the design phase to avoid operational issues later on. The RSI dynamic response amplitudes are driven by three main factors: (1) pressure forcing amplitudes, (2) excitation frequencies in relation to natural frequencies and (3) damping. The prediction of the two first factors has been largely documented in the literature. However, the prediction of fluid damping has received less attention in spite of being critical when the runner is close to resonance. Experimental damping measurements in flowing water on hydrofoils were presented previously. Those results showed that the hydro-dynamic damping increased linearly with the flow. This paper presents development and validation of a mathematical model, based on momentum exchange, to predict damping due to fluid structure interaction in flowing water. The model is implemented as an analytical procedure for simple structures, such as cantilever beams, but is also implemented in more general ways using three different approaches for more complex structures such as runner blades: a finite element procedure, a CFD modal work based approach and a CFD 1DOF approach. The mathematical model and all three implementation approaches are shown to agree well with experimental results.

  3. Flow development investigation of concentrated unstable oil-water dispersions in turbulent pipe flows

    NASA Astrophysics Data System (ADS)

    Voulgaropoulos, Victor; Weheliye, Weheliye; Chinaud, Maxime; Angeli, Panagiota; Karolina Ioannou Collaboration

    2015-11-01

    This study explores the separation characteristics of unstable oil-water dispersed flows in pipes. The test section is a 7 m long acrylic pipe with a 37mm ID and the fluids used are tap water and an Exxsol oil (6.6cSt) An inlet system with more than a thousand capillary tubes of 1mm ID is implemented to actuate highly concentrated dispersions for a wider range of flow rates. High speed imaging combined with ring conductivity probes and pressure transducers are implemented in several axial positions along the pipe to study the flow development. Phase distribution and continuity are measured in the pipe cross-section and drop size information is acquired by high frequency dual impedance probes. The coalescence and sedimentation dynamics of the concentrated dispersions and the development of separate layers downstream the pipe are investigated. The experimental results are coupled with theoretical and semi-empirical models in an effort to predict the separation properties of the highly concentrated dispersed flows. Chevron Energy Technology, Houston, USA.

  4. Hydrothermal alteration of kimberlite by convective flows of external water

    NASA Astrophysics Data System (ADS)

    Afanasyev, Andrey; Melnik, Oleg; Porritt, Lucy; Schumacher, John; Sparks, Steve

    2015-04-01

    Kimberlite volcanism involves the emplacement of olivine-rich volcaniclastic deposits into volcanic vents or pipes. Kimberlite deposits are typically pervasively serpentinised as a result of the reaction of olivine and water within a temperature range of 130-400 °C or less. We present a model for the influx of ground water into hot kimberlite deposits coupled with progressive cooling and serpentisation. In order to simulate cooling of a kimberlite body by external water influx, we have used a modified version of the filtration code MUFITS (www.mufits.imec.msu.ru). The code is developed for simulation of multiphase multicomponent flows in porous media in a wide range of pressures and temperatures, including sub-critical and supercritical conditions. It solves mass conservation laws for individual components (water and a proxy component, not participating in serpentinisation) together with energy equation for the system as a whole including the solid rock matrix, and Darcy transport equations for different phases. Two modifications of the code were implemented: Serpentinisation of the olivine leads to a decrease in the density of the rock matrix and filling pore spaces resulting in significant decrease in porosity and permeability; latent heat of serpentinisation is accounted for in the energy equation. The simulation results indicate that large-pressure gradients cause influx and heating of water within the pipe with horizontal convergent flow in the host rock and along pipe margins, and upward flow within the pipe centre. Complete serpentisation is predicted for wide ranges of permeability of the host rocks and kimberlite deposits. For typical pipe dimensions, cooling times are centuries to a few millennia. Excess volume of serpentine results in filling of pore spaces, eventually inhibiting fluid flow. Fresh olivine is preserved in lithofacies with initial low porosity, and at the base of the pipe where deeper-level host rocks have low permeability, and the pipe

  5. Resistance to Water Flow in the Sorghum Plant 1

    PubMed Central

    Meyer, Wayne S.; Ritchie, Joe T.

    1980-01-01

    Knowledge of the location and magnitude of the resistance to water flow in a plant is fundamental for describing whole plant response to water stress. The reported magnitudes of these resistances vary widely, principally because of the difficulty of measuring water potential within the plant. A number of interrelated experiments are described in which the water potential of a covered, nontranspiring leaf attached to a transpiring sorghum plant (Sorghum bicolor [L.] Moench) was used as a measure of the potential at the root-shoot junction. This allowed a descriptive evaluation of plant resistance to be made. The water potentials of a covered, nontranspiring leaf and a nonabsorbing root in solution, both attached to an otherwise actively transpiring and absorbing plant, were found to be similar. This supported the hypothesis that covered leaf water potential was equilibrating at a point shared by the vascular connections of both leaves and roots, i.e. the nodal complex of the root-shoot junction or crown. The difference in potential between a covered and exposed leaf together with calculated individual leaf transpiration rates were used to evaluate the resistance between the plant crown and the exposed leaf lamina called the connection resistance. There was an apparent decrease in the connection resistance as the transpiration rate increased; this is qualitatively explained as plant capacitance. Assuming that the covered leaf water potential was equal to that in the root xylem at the point of water absorption in the experimental plants with relatively short root axes, calculated radial root resistances were strongly dependent on the transpiration rate. For plants with moderate to high transpiration rates the roots had a slightly larger resistance than the shoots. PMID:16661138

  6. Definition of hydraulic stability of KVGM-100 hot-water boiler and minimum water flow rate

    NASA Astrophysics Data System (ADS)

    Belov, A. A.; Ozerov, A. N.; Usikov, N. V.; Shkondin, I. A.

    2016-08-01

    In domestic power engineering, the methods of quantitative and qualitative-quantitative adjusting the load of the heat supply systems are widely distributed; furthermore, during the greater part of the heating period, the actual discharge of network water is less than estimated values when changing to quantitative adjustment. Hence, the hydraulic circuits of hot-water boilers should ensure the water velocities, minimizing the scale formation and excluding the formation of stagnant zones. The results of the calculations of hot-water KVGM-100 boiler and minimum water flow rate for the basic and peak modes at the fulfillment of condition of the lack of surface boil are presented in the article. The minimal flow rates of water at its underheating to the saturation state and the thermal flows in the furnace chamber were defined. The boiler hydraulic calculation was performed using the "Hydraulic" program, and the analysis of permissible and actual velocities of the water movement in the pipes of the heating surfaces was carried out. Based on the thermal calculations of furnace chamber and thermal- hydraulic calculations of heating surfaces, the following conclusions were drawn: the minimum velocity of water movement (by condition of boiling surface) at lifting movement of environment increases from 0.64 to 0.79 m/s; it increases from 1.14 to 1.38 m/s at down movement of environmental; the minimum water flow rate by the boiler in the basic mode (by condition of the surface boiling) increased from 887 t/h at the load of 20% up to 1074 t/h at the load of 100%. The minimum flow rate is 1074 t/h at nominal load and is achieved at the pressure at the boiler outlet equal to 1.1 MPa; the minimum water flow rate by the boiler in the peak mode by condition of surface boiling increases from 1669 t/h at the load of 20% up to 2021 t/h at the load of 100%.

  7. On the biases affecting water ages inferred from isotopic data

    NASA Astrophysics Data System (ADS)

    Cornaton, F. J.; Park, Y.-J.; Deleersnijder, E.

    2011-11-01

    SummaryGroundwater age has become a fundamental concept in groundwater hydrology, but ages originating from isotopic analyses are still identified with a lack of clarity and using models that occasionally are unrealistic. If the effect of advection and dispersion on water ages has already been extensively identified, very few studies address the reliability of using radiometric ages as derived from isotopic data to estimate aquifer properties such as average velocities. Using simple one-dimensional and two-dimensional analytical solutions for single-site and two-sites mobile-immobile systems, we compare the radiometric ages to the mean ages (or residence times) as deduced from a direct, physically-based simulation approach (using the mean age equation), and show that the competition between isotope decay rate and dispersion coefficient can generate important discrepancies between the two types of ages. A correction for the average apparent velocity originating from apparent isotopic ages is additionally provided. The particular case of the tritium age dating method is also addressed, and a numerical example is finally given for illustrating the analysis considering a more complex and heterogeneous aquifer system. Our results suggest that age definitions based on the radioactivity of isotopes may not be representative for the mean age of the sample or for the groundwater velocity at given locations, and may not always be suitable for constraining the calibration of hydrogeological models.

  8. Swirl combustor flow visualization studies in a water tunnel

    NASA Astrophysics Data System (ADS)

    Schetz, J. A.; Hewitt, P. W.; Thomas, R.

    1983-12-01

    The flowfield in a highly swirling combustor with a Confinement Ratio of 1.0, a bypass flow (secondary downstream air injection), aspiration holes in the burner can and a large central hub was simulated. Data was collected from visualization with neutral density plastic beads in water, and velocity and turbulence level profiles measured in cold air tests. The baseline case produced little noticeable recirculation. Increasing the confinement ratio to a maximum of 2.1 either by insert rings or a larger burner can generally strengthened the central zone to a state of incipient recirculation. Use of a convergent/divergent outer ring after the swirl section had further beneficial effects. The bypass flow reduced the radial extent and intensified the central zone of incipient recirculation while confining the flow aerodynamically by shifting velocity peaks toward the axis. Extended central hubs, although having little effect on the flow in the burner can, produced a rotating helix in the afterburner. Aspiration holes reduced velocity levels along the wall.

  9. Carbon Nanotubes in Water: MD Simulations of Internal and External Flow, Self Organization

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard L.; Halicioglu, Timur; Werder, Thomas; Walther, Jens; Koumoutsakos, Petros; Arnold, James (Technical Monitor)

    2001-01-01

    We have developed computational tools, based on particle codes, for molecular dynamics (MD) simulation of carbon nanotubes (CNT) in aqueous environments. The interaction of CNTs with water is envisioned as a prototype for the design of engineering nano-devices, such as artificial sterocillia and molecular biosensors. Large scale simulations involving thousands of water molecules are possible due to our efficient parallel MD code that takes long range electrostatic interactions into account. Since CNTs can be considered as rolled up sheets of graphite, we expect the CNT-water interaction to be similar to the interaction of graphite with water. However, there are fundamental differences between considering graphite and CNTs, since the curvature of CNTs affects their chemical activity and also since capillary effects play an important role for both dynamic and static behaviour of materials inside CNTs. In recent studies Gordillo and Marti described the hydrogen bond structure as well as time dependent properties of water confined in CNTs. We are presenting results from the development of force fields describing the interaction of CNTs and water based on ab-initio quantum mechanical calculations. Furthermore, our results include both water flows external to CNTs and the behaviour of water nanodroplets inside heated CNTs. In the first case (external flows) the hydrophobic behaviour of CNTs is quantified and we analyze structural properties of water in the vicinity of CNTs with diagnostics such as hydrogen bond distribution, water dipole orientation and radial distribution functions. The presence of water leads to attractive forces between CNTs as a result of their hydrophobicity. Through extensive simulations we quantify these attractive forces in terms of the number and separation of the CNT. Results of our simulations involving arrays of CNTs indicate that these exhibit a hydrophobic behaviour that leads to self-organising structures capable of trapping water clusters

  10. Experimental verification of the four-sensor probe model for flow diagnosis in air water flow in vertical pipe

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Mishra, R.

    2012-05-01

    Measuring the volumetric flow rate of each of the flowing components is required to be monitored in production logging applications. Hence it is necessary to measure the flow rates of gas, oil and water in vertical and inclined oil wells. An increasing level of interest has been shown by the researchers in developing system for the flow rate measurement in multiphase flows. This paper describes the experimental methodology using a miniature, local four-sensor probe for the measurement of dispersed flow parameters in bubbly two-phase flow for spherical bubbles. To establish interdependent among different parameters corresponding to dispersed flow, the available model has been used to experimentally obtain different parameters such as volume fraction, velocity and bubble shape of the dispersed phase in the bubbly air-water flow.

  11. SSDA code to apply data assimilation in soil water flow modeling: Documentation and user manual

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water flow models are based on simplified assumptions about the mechanisms, processes, and parameters of water retention and flow. That causes errors in soil water flow model predictions. Data assimilation (DA) with the ensemble Kalman filter (EnKF) corrects modeling results based on measured s...

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    be very similar and likely functionally related. Our experimental field data were used for modelling water flow and solute transport in floating fens, using HYDRUS 2D. Fluctuations of surface water and root mat, as well as geometry and unsaturated zone parameters can have a major influence on groundwater fluctuations and the exchange between rain and surface water and the water in the root mats. In combination with the duration of salt pulses in surface water, and sensitivity of fen plants to salinity (Stofberg et al. 2014, submitted), risks for rare plants can be anticipated.

  13. Flow-induced vibration of component cooling water heat exchangers

    SciTech Connect

    Yeh, Y.S.; Chen, S.S. . Nuclear Engineering Dept.; Argonne National Lab., IL )

    1990-01-01

    This paper presents an evaluation of flow-induced vibration problems of component cooling water heat exchangers in one of Taipower's nuclear power stations. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support-plate (TSP)-inactive modes, and fluidelastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified. 11 refs., 19 figs., 3 tabs.

  14. The design of water markets when instream flows have value.

    PubMed

    Murphy, James J; Dinar, Ariel; Howitt, Richard E; Rassenti, Stephen J; Smith, Vernon L; Weinberg, Marca

    2009-02-01

    The main objective of this paper is to design and test a decentralized exchange mechanism that generates the location-specific pricing necessary to achieve efficient allocations in the presence of instream flow values. Although a market-oriented approach has the potential to improve upon traditional command and control regulations, questions remain about how these rights-based institutions can be implemented such that the potential gains from liberalized trade can be realized. This article uses laboratory experiments to test three different water market institutions designed to incorporate instream flow values into the allocation mechanism through active participation of an environmental trader. The smart, computer-coordinated market described herein offers the potential to significantly reduce coordination problems and transaction costs associated with finding mutually beneficial trades that satisfy environmental constraints. We find that direct environmental participation in the market can achieve highly efficient and stable outcomes, although the potential does exist for the environmental agent to influence outcomes. PMID:18499333

  15. [Characteristics of Caragana microphylla sap flow and water consumption under different weather conditions on Horqin sandy land of northeast China].

    PubMed

    Yue, Guang-Yang; Zhao, Ha-Lin; Zhang, Tong-Hui; Yun, Jian-Ying; Niu, Li; He, Yu-Hui

    2007-10-01

    Employing heat balance Dynamax packaged sap flow measuring system and automatic weather recording system, the sap flow of artificial Caragana microphylla community on Horqin sandy land of northeast China was monitored consecutively in 2006, and the photosynthetically effective radiation, air temperature, relative humidity and wind velocity were measured synchronously. According to the manual records of weather conditions, four most representative weather conditions were gathered up to analyze the relationships of C. microphylla sap flow and its single branch water consumption with test meteorological factors. The results showed that under high air temperature and intense radiation on sunny days, the diurnal variation of C. microphylla sap flow appeared a broad peak curve, so as to adapt the circumstance of drought and water shortage via lower transpiration. The diurnal variations of sap flow and its dominant affecting factors differed with weather conditions, and photosynthetically effective radiation was always the dominant factor affecting the sap flow. The variation of the sap flow was the result of comprehensive effects of multi-meteorological factors, and the overall variation trend of water consumption of single branch was declined in the order of sunny days > cloudy days > windy days > rainy days, with the mean value being 459, 310, 281 and 193 mg x d(-1), respectively. PMID:18163294

  16. What maintains the waters flowing in our rivers? - Rethinking hydrogeology to improve public policy

    NASA Astrophysics Data System (ADS)

    Vasconcelos, Vitor Vieira

    2016-01-01

    This article discusses how new contributions from hydrogeological science in the 20th and 21st centuries have allowed for a better understanding of the processes that affect the maintenance of river flows. Moreover, the way in which this knowledge has been conveyed beyond academia and has been gradually incorporated into public policy for natural resource management is also discussed. This article explains the development of several approaches used to understand the relationships among the management of aquifers, vegetation and river flows, including water balance, aquifer recharge, the piston effect, seasonal effects, and safe and sustainable yields. Additionally, the current challenges regarding the modeling of hydrological processes that integrate groundwater and surface waters are discussed. Examples of studies applied in Brazil that demonstrate these processes and stimulate thought regarding water management strategies are presented. In light of the case studies, it is possible to propose different strategies, each adapted for specific hydrogeological context to maximize aquifer recharge or base flow maintenance. Based on these strategies, the role of infiltration ponds and other artificial recharge techniques is re-evaluated in the context of the mitigation of environmental impacts on the maintenance of river flows. Proposals for the improvement of public policies regarding the payment of related environmental services to stimulate investment in aquifer recharge and the maintenance of base flow, for which the goal is to attain win-win-win situations for the environment, farmers and water users, while preventing land speculation, are discussed. Lastly, a conceptual model for the dissemination of hydrogeological knowledge in public policies is provided, and its challenges and possibilities are discussed.

  17. Overland flow generation mechanisms affected by topsoil treatment: Application to soil conservation

    NASA Astrophysics Data System (ADS)

    González Paloma, Hueso; Juan Francisco, Martinez-Murillo; Damian, Ruiz-Sinoga Jose; Hanoch, Lavee

    2015-04-01

    decreased from 5 to 10 cm depth. According to the results, the hydrological and erosive response in the five treatments showed dissimilarities, despite having similar rainfall exposure and the same original soil properties. This means that the differences between the treatments play a key role in the soil moisture, overland flow and sediment yield values. The study has demonstrated the effects of various treatments on the generation of overland flow, and hence the sediment yield. In the C and HP plots, relatively large amounts of overland flow rapidly developed. This cannot be explained by saturation conditions, as the soil moisture content was highest near the surface and decreased with depth in the profile. This, together with the relatively low macro-porosity, proved that the mechanism of overland flow generation was of the Hortonian type. On the other hand, in the SM and PM plots, the high level of macro-porosity, together with the increase in soil moisture content with depth, explained the small quantities of overland flow and sediment yield. In the rare case that overland flow developed in these plots, it was minor in amount, and yielded little sediment because of saturation conditions. The processes in the RU plots were more complicated; from 10 cm depth the soil moisture content always increased with further depth, usually rapidly. Thus, water infiltrated continuously and there was no rainfall excess. Therefore, in terms of overland flow and sediment yield, the RU plots behaved in a similar way to the SM and PM plots. The fact that the soil moisture content was low at depths of 10 cm is because of the uptake of water at these depths by the roots of Carlina hispanica Lam. From a land management standpoint, the SM, PM and RU treatments were the most effective in reducing overland flow and sediment yield following afforestation. In addition, the soil profile became more wettable, which provided more water to support plant survival. However, when afforestation was

  18. Numerical simulation of flow generated in a closed water areas

    NASA Astrophysics Data System (ADS)

    Chen, Narisu; Yamamoto, Kazuhiro; Katayama, Yuki; Watanabe, Masaji

    2016-02-01

    Techniques to analyze the bottom topography in a closed water area are described. Positioning data are recorded with a global positioning system, and depth data are recorded with an echo sounder. Positioning data and depth data are synchronized to generate three-dimensional topographical data. Errors due to ship's movement are corrected using outputs from a clinometer and a compass. The change due to sedimentation is investigated for the bottom topography of Kojima Lake. We describe numerical techniques based on a finite-element method and an explicit time integration method to analyze flow generated in Kojima Lake.

  19. Application of the Analogy Between Water Flow with a Free Surface and Two-Dimensional Compressible Gas Flow

    NASA Technical Reports Server (NTRS)

    Orlin, W James; Lindner, Norman J; Butterly, Jack G

    1947-01-01

    The theory of the hydraulic analogy -- that is, the analogy between water flow with a free surface and two-dimensional compressible gas flow -- and the limitations and conditions of the analogy are discussed. A test was run using the hydraulic analogy as applied to the flow about circular cylinders of various diameters at subsonic velocities extending into the supercritical range. The apparatus and techniques used in this application are described and criticized. Reasonably satisfactory agreement of pressure distributions and flow fields existed between water and air flow about corresponding bodies. This agreement indicated the possibility of extending experimental compressibility research by new methods.

  20. Fire affects root decomposition, soil food web structure, and carbon flow in tallgrass prairie

    NASA Astrophysics Data System (ADS)

    Shaw, E. Ashley; Denef, Karolien; Milano de Tomasel, Cecilia; Cotrufo, M. Francesca; Wall, Diana H.

    2016-05-01

    Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is common and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root-litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root-litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable but also significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition, which, in turn, is significantly affected by fire. Not

  1. Burning management in the tallgrass prairie affects root decomposition, soil food web structure and carbon flow

    NASA Astrophysics Data System (ADS)

    Shaw, E. A.; Denef, K.; Milano de Tomasel, C.; Cotrufo, M. F.; Wall, D. H.

    2015-09-01

    Root litter decomposition is a major component of carbon (C) cycling in grasslands, where it provides energy and nutrients for soil microbes and fauna. This is especially important in grasslands where fire is a common management practice and removes aboveground litter accumulation. In this study, we investigated whether fire affects root decomposition and C flow through the belowground food web. In a greenhouse experiment, we applied 13C-enriched big bluestem (Andropogon gerardii) root litter to intact tallgrass prairie soil cores collected from annually burned (AB) and infrequently burned (IB) treatments at the Konza Prairie Long Term Ecological Research (LTER) site. Incorporation of 13C into microbial phospholipid fatty acids and nematode trophic groups was measured on six occasions during a 180-day decomposition study to determine how C was translocated through the soil food web. Results showed significantly different soil communities between treatments and higher microbial abundance for IB. Root decomposition occurred rapidly and was significantly greater for AB. Microbes and their nematode consumers immediately assimilated root litter C in both treatments. Root litter C was preferentially incorporated in a few groups of microbes and nematodes, but depended on burn treatment: fungi, Gram-negative bacteria, Gram-positive bacteria, and fungivore nematodes for AB and only omnivore nematodes for IB. The overall microbial pool of root litter-derived C significantly increased over time but was not significantly different between burn treatments. The nematode pool of root litter-derived C also significantly increased over time, and was significantly higher for the AB treatment at 35 and 90 days after litter addition. In conclusion, the C flow from root litter to microbes to nematodes is not only measurable, but significant, indicating that higher nematode trophic levels are critical components of C flow during root decomposition which, in turn, is significantly

  2. Simulated water sources and effects of pumping on surface and ground water, Sagamore and Monomoy flow lenses, Cape Cod, Massachusetts

    USGS Publications Warehouse

    Walter, Donald A.; Whealan, Ann T.

    2005-01-01

    The sandy sediments underlying Cape Cod, Massachusetts, compose an important aquifer that is the sole source of water for a region undergoing rapid development. Population increases and urbanization on Cape Cod lead to two primary environmental effects that relate directly to water supply: (1) adverse effects of land use on the quality of water in the aquifer and (2) increases in pumping that can adversely affect environmentally sensitive surface waters, such as ponds and streams. These considerations are particularly important on the Sagamore and Monomoy flow lenses, which underlie the largest and most populous areas on Cape Cod. Numerical models of the two flow lenses were developed to simulate ground-water-flow conditions in the aquifer and to (1) delineate areas at the water table contributing water to wells and (2) estimate the effects of pumping and natural changes in recharge on surface waters. About 350 million gallons per day (Mgal/d) of water recharges the aquifer at the water table in this area; most water (about 65 percent) discharges at the coast and most of the remaining water (about 28 percent) discharges into streams. A total of about 24.9 Mgal/d, or about 7 percent, of water in the aquifer is withdrawn for water supply; most pumped water is returned to the hydrologic system as return flow creating a state of near mass balance in the aquifer. Areas at the water table that contribute water directly to production wells total about 17 square miles; some water (about 10 percent) pumped from the wells flows through ponds prior to reaching the wells. Current (2003) steady-state pumping reduces simulated ground-water levels in some areas by more than 4 feet; projected (2020) pumping may reduce water levels by an additional 3 feet or more in these same areas. Current (2003) and future (2020) pumping reduces total streamflow by about 4 and 9 cubic feet per second (ft3/s), corresponding to about 5 percent and 9 percent, respectively, of total streamflow

  3. Factors affecting regional pulmonary blood flow in chronic ischemic heart disease

    SciTech Connect

    Pistolesi, M.; Miniati, M.; Bonsignore, M.; Andreotti, F.; Di Ricco, G.; Marini, C.; Rindi, M.; Biagini, A.; Milne, E.N.; Giuntini, C.

    1988-07-01

    To assess the effect of left heart disease on pulmonary blood flow distribution, we measured mean pulmonary arterial and wedge pressures, cardiac output, pulmonary vascular resistance, pulmonary blood volume, and arterial oxygen tension before and after treatment in 13 patients with longstanding ischemic heart failure and pulmonary edema. Pulmonary edema was evaluated by a radiographic score, and regional lung perfusion was quantified on a lung scan by the upper to lower third ratio (U:L ratio) of pulmonary blood flow per unit of lung volume. In all cases, redistribution of lung perfusion toward the apical regions was observed; this pattern was not affected by treatment. After treatment, pulmonary vascular pressures, resistance, and edema were reduced, while pulmonary blood volume did not change. At this time, pulmonary vascular resistance showed a positive correlation with the U:L ratio (r = 0.78; P less than 0.01), whereas no correlation was observed between U:L ratio and wedge pressure, pulmonary edema, or arterial oxygen tension. Hence, redistribution of pulmonary blood flow, in these patients, reflects chronic structural vascular changes prevailing in the dependent lung regions.

  4. Roles of temperature and flow velocity on the mobility of nano-sized titanium dioxide in natural waters.

    PubMed

    Lv, Xiaohui; Tao, Jing; Chen, Baiyang; Zhu, Xiaoshan

    2016-09-15

    While environmental fate and transport of nano-sized TiO2 (nTiO2) attracts intensive attention, how physical characters of natural waters, such as water type, temperature, and flowing velocity, impact the mobility of nTiO2 remain unclear now. In this work, ultrapure water, lake water, and sea water were chosen to investigate the aggregation and sedimentation behaviors of nTiO2 under a series of environmental conditions with varying feeding concentration, water temperature, and flow velocity. In general, the results demonstrated poorer stability of nTiO2 in sea water than other water types. After a 7-hour test (initial nTiO2=100mg/L), the nTiO2 hydrodynamic sizes, sedimentation rates, and zeta potentials differed significantly in ultrapure water (545nm, 24%, -30mV), lake water (1374nm, 56%, -16mV) and sea water (2152nm, 87%, -3mV). Meanwhile, the study exhibited significant influences of initial nTiO2 concentration (10-100mg/L) on the behaviors of nTiO2 in sea water and lake water but negligible impact on ultrapure water. Ambient temperature also directly affected the aggregation and sedimentation rates of nTiO2, both hydrodynamic diameters and sedimentation of nTiO2 increased markedly with the rising ambient temperatures (10-60°C). In contrast, increasing water flow velocity (0-0.32m/s) lowered the hydrodynamic diameters and sedimentation rates of nTiO2, although the influence of flowing velocity on the aggregation of nTiO2 was partially reversible. PMID:26970667

  5. Microscale Modelling of Water and Gas-Water Flows in Subsea Sand Sediment

    NASA Astrophysics Data System (ADS)

    Sato, T.; Sugita, T.; Hirabayashi, S.; Nagao, J.; Jin, Y.; Kiyono, F.

    2009-12-01

    Methane hydrate is a promising energy resource in the near future. Its production is a current hot topic and flow of methane gas with water in sediment sand layer is very important to predict the production rate. In this study, permeability of microscale sand layer was numerically simulated by a three-dimensional lattice Boltzmann method. Shapes of real sands were extracted by series expansion of spherical harmonics using CT-scan images of real subsea core samples. These extracted sands were located in a cubic lattice domain by a simulated annealing method to fit to given porosities. Pressure difference was imposed at the both end faces of the domain to flow water and methane gas. By this simulation, permeability of water phase and water-gas two-phase flow were analysed and compared well with existing models. This work was financially supported by Japan's Methane Hydrate R&D Program planned by Ministry of Economy, Trade and Industry (METI). 3D image of an extracted frame-sand grain Distribution of gas and water phases in computational domain for Sw=0.80

  6. Impacts of human activities and climate variability on green and blue water flows in the Heihe River Basin in Northwest China

    NASA Astrophysics Data System (ADS)

    Zang, C.; Liu, J.; Jiang, L.; Gerten, D.

    2013-07-01

    Human activities and climate factors both affect the availability of water resources and the sustainability of water management. Especially in already dry regions, water has become more and more scarce with increasing requirements from growing population, economic development and diet shifts. Although progress has been made in understanding variability of runoff, the impacts of climate variability and human activities on flows of both green water (actual evapotranspiration) and blue water (discharge accumulated in the river network) remain less well understood. We study the spatial patterns of blue and green water flows and the impacts on them of human activities and climate variability as simulated by the Soil and Water Assessment Tool (SWAT) for an inland Heihe river basin located in Northwest China. The results show that total green and blue water flow increased from 1980 to 2005, mainly as a result of climate variability (upward precipitation trends). Direct human activities did not significantly change the total green and blue water flow. However, land use change led to a transformation of 206 million m3 from green to blue water flow, while farmland irrigation expansion resulted in a transformation of 66 million m3 from blue to green water flow. The synchronous climate variability caused an increase of green water flow by 469 million m3 and an increase of blue water flow by 146 million m3 at the river basin level, while the geographical distribution showed an uneven change even with reductions of water flows in western sub-basins at midstream. The results are helpful to benchmark the water resources in the context of global change in the inland river basins in China. This study also provides a general approach to investigate the impacts of historical human activities and climate variability on green and blue water flows at the river basin level.

  7. Experimental Studies on the Measurement of Oil-water Two-phase Flow

    NASA Astrophysics Data System (ADS)

    Ma, Longbo; Zhang, Hongjian; Hua, Yuefang; Zhou, Hongliang

    2007-06-01

    Oil-water two-phase flow measurement was investigated with a Venturi meter and double-U Coriolis meter in this work. Based on the Venturi differential pressure and the quality of two-phase flow, a model for measuring oil-water mass flow rate was developed, in which fluid asymmetry of oil-water two-phase flow was considered. However, measuring the quality of two-phase flow on-line is rather difficult at present. Though double-U Coriolis meter can provide accurate measurement of two-phase flow, it can not provide desired respective mass flow rate. Therefore, a double-parameter measurement method with Venturi meter and double-U Coriolis meter is proposed. According to the flow rate requirement of Venturi, a new flow regime identification method based on Support Vector Machine (SVM) has been developed for the separated flow and the dispersed flow. With the Venturi model developed in this paper and mass flow rate of oil-water mixture measured with double-U Coriolis meter, mixture mass flow rate, oil mass flow rate and water mass flow rate could be obtained by the correlation. Experiments of flow rate measurement of oil-water two-phase flow were carried out in the horizontal tube with 25mm inner diameter. The water fraction range is from 5% to 95%. Experimental results showed that the flow regime could be identified well with SVM, and the relative error of the total mass flow rate and respective mass flow rate of oil-water two-phase flow was less than ±1.5% and ±10%, respectively.

  8. Well-to-Wheels Water Consumption: Tracking the Virtual Flow of Water into Transportation

    NASA Astrophysics Data System (ADS)

    Lampert, D. J.; Elgowainy, A.; Hao, C.

    2015-12-01

    Water and energy resources are fundamental to life on Earth and essential for the production of consumer goods and services in the economy. Energy and water resources are heavily interdependent—energy production consumes water, while water treatment and distribution consume energy. One example of this so-called energy-water nexus is the consumption of water associated with the production of transportation fuels. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can be used to compare the environmental impacts of different transportation fuels on a consistent basis. In this presentation, the expansion of GREET to perform life cycle water accounting or the "virtual flow" of water into transportation and other energy sectors and the associated implications will be discussed. The results indicate that increased usage of alternative fuels may increase freshwater resource consumption. The increased water consumption must be weighed against the benefits of decreased greenhouse gas and fossil energy consumption. Our analysis highlights the importance of regionality, co-product allocation, and consistent system boundaries when comparing the water intensity of alternative transportation fuel production pathways such as ethanol, biodiesel, compressed natural gas, hydrogen, and electricity with conventional petroleum-based fuels such as diesel and gasoline.

  9. Use of a novel new irrigation system to observe and model water vapor flow through dry soils

    NASA Astrophysics Data System (ADS)

    Todman, L. C.; Ireson, A. M.; Butler, A. P.; Templeton, M.

    2013-12-01

    In dry soils hydraulic connectivity within the liquid water phase decreases and vapor flow becomes a significant transport mechanism for water. The temperature or solute concentration of the liquid phase affects the vapor pressure of the surrounding air, thus temperature or solute gradients can drive vapor flows. However, in extremely dry soils where water is retained by adsorption rather than capillarity, vapor flows can also occur. In such soils tiny changes in water content significantly affect the equilibrium vapor pressure in the soil, and hence small differences in water content can initiate vapor pressure gradients. In many field conditions this effect may be negligible compared to vapor flows driven by other factors. However, flows of this type are particularly significant in a new type of subsurface irrigation system which uses pervaporation, via a polymer tubing, as the mechanism for water supply. In this system, water enters the soil in vapor phase. Experiments using this system therefore provide a rare opportunity to observe vapor flows initiating from a subsurface source without significant injection of heat. A model was developed to simulate water flow through the soil in liquid and vapor phase. In this model it was assumed that the two phases were in equilibrium. The equilibrium relationship was defined by a new mathematical expression that was developed to fit experimental data collected to characterize the sorption isotherm of three soils (sand, saline sand and top soil). The osmotic potential of the saline sand was defined as a function of water content using a continuous mathematical expression. The model was then calibrated to fit the data from laboratory experiments, in which the vapor flow into and out of the soil were quantified. The model successfully reproduced experimental observations of the total water flux, relative humidity and water content distribution in three soil types. This suggests that the model, including the proposed

  10. Fate and transport of oil sand process-affected water into the underlying clay till: a field study.

    PubMed

    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 ((2)H and (18)O). The distribution of conservative tracers ((18)O 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. PMID:23752067

  11. Flow of gasoline-in-water microemulsion through water-saturated soil columns

    SciTech Connect

    Ouyang, Y.; Mansell, R.S.; Rhue, R.D.

    1995-05-01

    Much consideration has been given to the use of surfactants to clean up nonaqueous phase liquids (NAPLs) from contaminated soil and ground water. Although this emulsification technique has shown significant potential for application in environmental remediation practices, a major obstacle leading to low washing efficiency is the potential formation of macroemulsion with unfavorable flow characteristics in porous media. This study investigated influences of the flow of leaded-gasoline-in-water (LG/W) microemulsion upon the transport of gasoline and lead (Pb) species in water-saturated soil columns. Two experiments were performed: (1) the immiscible displacement of leaded gasoline and (2) the miscible displacement of LG/W microemulsion through soil columns, followed by sequentially flushing with NaCl solution and a water/surfactant/cosurfactant (W/S/CoS) mixture. Comparison of breakthrough curves (BTC) for gasoline between the two experiments shows that about 90% of gasoline and total Pb were removed from the soil columns by NaCl solution in the LG/W microemulsion experiment as compared to 40% removal of gasoline and 10% removal of total Pb at the same process in the leaded gasoline experiment. Results indicate that gasoline and Pb species moved much more effectively through soil during miscible flow of LG/W microemulsion than during immiscible flow of leaded gasoline. In contrast to the adverse effects of macroemulsion on the transport of NAPLs, microemulsion was found to enhance the transport of gasoline through water-saturated soil. Mass balance analysis shows that the W/S/CoS mixture had a high capacity for removing residual gasoline and Pb species from contaminated soil. Comparison of water-pressure differences across the soil columns for the two experiments indicates that pore clogging by gasoline droplets was greatly minimized in the LG/W microemulsion experiment.

  12. Stability of Flow in a Steam-Water Geothermal Wall

    NASA Astrophysics Data System (ADS)

    Shulyupin, A. N.

    2016-05-01

    It has been shown that the existing notion about flow stability in a steam-water well cannot explain all experimentally observed features of the interrelationship between the wellhead pressure and the flow rate. We propose a new interpretation of the stability condition based on the analysis of the reaction of the well and the feed reservoir to bottom hole pressure fluctuations at given conditions at the well inlet and outlet. It has been established that the stable regime corresponds to a negative value of the criterion defined as a ratio between the derivative characteristics of the well and the reservoir, and to obtain a characteristic, it is necessary to take into account the pressure loss in the equipment placed between the wellhead and the medium with a constant pressure. Such an approach and the new interpretation explain the practically observed features of the interrelationship between the wellhead pressure and the flow rate. It has been shown that the additional drag on the wellhead can stabilize the operating conditions of the well.

  13. Stability of Flow in a Steam-Water Geothermal Wall

    NASA Astrophysics Data System (ADS)

    Shulyupin, A. N.

    2016-06-01

    It has been shown that the existing notion about flow stability in a steam-water well cannot explain all experimentally observed features of the interrelationship between the wellhead pressure and the flow rate. We propose a new interpretation of the stability condition based on the analysis of the reaction of the well and the feed reservoir to bottom hole pressure fluctuations at given conditions at the well inlet and outlet. It has been established that the stable regime corresponds to a negative value of the criterion defined as a ratio between the derivative characteristics of the well and the reservoir, and to obtain a characteristic, it is necessary to take into account the pressure loss in the equipment placed between the wellhead and the medium with a constant pressure. Such an approach and the new interpretation explain the practically observed features of the interrelationship between the wellhead pressure and the flow rate. It has been shown that the additional drag on the wellhead can stabilize the operating conditions of the well.

  14. Flow around a corner in the water impact problem

    SciTech Connect

    Krechetnikov, R.

    2014-07-15

    In this work, we study the local flow in the vicinity of a flat sector of arbitrary angle α in the water impact problem as motivated by recent experimental observations in the author's laboratory. The key question is as to why the ejecta formed during the impact at zero deadrise angle is considerably higher along a straight edge of the sector compared to that near a sharp corner α < π, e.g., if the impacting body is a rectangular plate. Resolving this question is made possible by the discovered here mathematical equivalence of the problem to electromagnetic diffraction phenomena. The main result of the present study is the revealed and quantified influence of the geometry of a flat plate corner on the fluid flow around it, which also contributes to the understanding of certain three-dimensional effects in the water impact problem and provides a generalization of the classical two-dimensional results on the impact at zero deadrise angle. The offered theoretical solution is also qualitatively supported with the help of particle image velocimetry measurements.

  15. Experimental and numerical simulations of heat transfers between flowing water and a horizontal frozen porous medium

    NASA Astrophysics Data System (ADS)

    Roux, N.; Costard, F.; Grenier, C. F.

    2013-12-01

    In permafrost-affected regions, hydrological changes due to global warming are still under investigation. But yet, we can already foresee from recent studies that for example, the variability and intensity of surface/subsurface flow are likely to be affected by permafrost degradation. And the feedback induced by such changes on permafrost degradation is still not clearly assessed. Of particular interest are lake and river-taliks. A talik is a permanently unfrozen zone that lies below rivers or lake. They should play a key role in these interactions given that they are the only paths for groundwater flow in permafrost regions. Thus heat transfers on a regional scale are potentially influenced by groundwater circulation. The aim of our study is therefore to investigate the evolution of river taliks. We developed a multidisciplinary approach coupling field investigation, experimental studies in a cold room and numerical modeling. In Central Yakutia, Siberia, where permafrost is continuous, we recently installed instruments to monitor ground temperature and water pressure in a river talik between two thermokarst lakes. We present here the coupling of numerical modeling and laboratory experiments in order to look after the main parameters controlling river-talik installation. In a cold room at IDES, where a metric scale channel is filled with sand as a porous medium, we are able to control air, water and permafrost temperature, but also water flow, so that we can test various parameter sets for a miniaturized river. These results are confronted with a numerical model developed at the LSCE with Cast3m (www-cast3m.cea.fr), that couples heat and water transfer. In particular, expressions for river-talik heat exchange terms are investigated. A further step will come in the near future with results from field investigation providing the full complexity of a natural system. Keywords: Talik, River, Numerical Modeling, Cold Room, Permafrost.

  16. Application and analysis of debris-flow early warning system in Wenchuan earthquake-affected area

    NASA Astrophysics Data System (ADS)

    Liu, D. L.; Zhang, S. J.; Yang, H. J.; Zhao, L. Q.; Jiang, Y. H.; Tang, D.; Leng, X. P.

    2016-02-01

    The activities of debris flow (DF) in the Wenchuan earthquake-affected area significantly increased after the earthquake on 12 May 2008. The safety of the lives and property of local people is threatened by DFs. A physics-based early warning system (EWS) for DF forecasting was developed and applied in this earthquake area. This paper introduces an application of the system in the Wenchuan earthquake-affected area and analyzes the prediction results via a comparison to the DF events triggered by the strong rainfall events reported by the local government. The prediction accuracy and efficiency was first compared with a contribution-factor-based system currently used by the weather bureau of Sichuan province. The storm on 17 August 2012 was used as a case study for this comparison. The comparison shows that the false negative rate and false positive rate of the new system is, respectively, 19 and 21 % lower than the system based on the contribution factors. Consequently, the prediction accuracy is obviously higher than the system based on the contribution factors with a higher operational efficiency. On the invitation of the weather bureau of Sichuan province, the authors upgraded their prediction system of DF by using this new system before the monsoon of Wenchuan earthquake-affected area in 2013. Two prediction cases on 9 July 2013 and 10 July 2014 were chosen to further demonstrate that the new EWS has high stability, efficiency, and prediction accuracy.

  17. Tangible Landscape: Cognitively Grasping the Flow of Water

    NASA Astrophysics Data System (ADS)

    Harmon, B. A.; Petrasova, A.; Petras, V.; Mitasova, H.; Meentemeyer, R. K.

    2016-06-01

    Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing - an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it - aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow.

  18. Neutron activation system using water flow for ITER

    NASA Astrophysics Data System (ADS)

    Nishitani, T.; Ebisawa, K.; Kasai, S.; Walker, C.

    2003-03-01

    A neutron activation system with flowing water using the 16O(n,p)16N reaction has been designed for the International Thermonuclear Experimental Reaction (ITER) neutron yield monitor with temporal resolution, based on the experimental results carried out at the fusion neutronics source (FNS) facility of the Japan Atomic Energy Research Institute. On ITER, irradiation ends will be installed in the filler shielding module between the blanket modules at the equatorial ports. The gamma-ray counting stations will be installed on the upstairs of the pit outside the biological shield. BGO (Bi4Ge3O12) scintillation detectors will be employed to measure 6.13 MeV gamma rays emitted from 16N. The distance between the irradiation end and the counting station is ˜20 m. The performance of the neutron activation system has been evaluated by using the neutron Monte Carlo code MCNP-4b with the JENDL 3.2 library. The reaction rate of 16O(n,p)16N was calculated not only at the irradiation end but also along the transfer line, which showed that the temporal resolution would be less than the ITER requirement of 100 ms including turbulent diffusion effects for the flow velocity of 10 m/s. With a flow velocity of 10 m/s, this system can measure the fusion power from 50 kW to 1 GW of the ITER operation by using two gamma-ray detectors; one detector faces the water pipe directly, and another has a collimator for higher-neutron yield. Also the calculation shows that the reaction rate is relatively insensitive to the change of the plasma position.

  19. Continuous-flow water sampler for real-time isotopic water measurements

    NASA Astrophysics Data System (ADS)

    Carter, J.; Dennis, K.

    2013-12-01

    Measuring the stable isotopes of liquid water (δ18O and δD) is a tool familiar to many Earth scientists, but most current techniques require discrete sampling. For example, isotope ratio mass spectrometry requires the collection of aliquots of water that are then converted to CO2, CO or H2 for analysis. Similarly, laser-based techniques, such as Cavity Ring-Down Spectroscopy (CRDS) convert discrete samples (typically < 2μL) of liquid water to water vapor using a flash vaporization process. By requiring the use of discrete samples fine-scale spatial and temporal studies of changes in δ18O and δD are limited. Here we present a continuous-flow water sampler that will enable scientists to probe isotopic changes in real-time, with applications including, but not limited to, quantification of the 'amount effect' (Dansgaard, 1964) during an individual precipitation event or storm track, real-time mixing of water in river systems, and shipboard continuous water measurements (Munksgaard et al., 2012). Due to the inherent ability of CRDS to measure a continuous flow of water vapor it is an ideal candidate for interfacing with a continuous water sampling system. Here we present results from the first commercially available continuous-flow water sampler, developed by engineers at Picarro. This peripheral device is compatible with Picarro CRDS isotopic water analyzers, allowing real-time, continuous isotopic measurements of liquid water. The new device, which expands upon the design of Munskgaard et al. (2011), utilizes expanded polytetrafluoroethylene (ePTFE) membrane technology to continuously generate gas-phase water, while liquid water is pumped through the system. The water vapor subsequently travels to the CRDS analyzer where the isotopic ratios are measured and recorded. The generation of water vapor using membrane technology is sensitive to environmental conditions, which if not actively control, lead to sustainable experimental noise and drift. Consequently, our

  20. Salinity and Alkaline pH in Irrigation Water Affect Marigold Plants: II. Mineral Ion Relations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scarcity of water of good quality for landscape irrigation is of outmost importance in arid and semiarid regions due to the competition with urban population. This is forcing the use of degraded waters with high levels of salinity and high pH, which may affect plant establishment and growth. The o...

  1. Determining the mean hydraulic gradient of ground water affected by tidal fluctuations

    USGS Publications Warehouse

    Serfes, Michael E.

    1991-01-01

    Tidal fluctuations in surface-water bodies produce progressive pressure waves in adjacent aquifers. As these pressure waves propagate inland, ground-water levels and hydraulic gradients continuously fluctuate, creating a situation where a single set of water-level measurements cannot be used to accurately characterize ground-water flow. For example, a time series of water levels measured in a confined aquifer in Atlantic City, New Jersey, showed that the hydraulic gradient ranged from .01 to .001 with a 22-degree change in direction during a tidal day of approximately 25 hours. At any point where ground water tidally fluctuates, the magnitude and direction of the hydraulic gradient fluctuates about the mean or regional hydraulic gradient. The net effect of these fluctuations on ground-water flow can be determined using the mean hydraulic gradient, which can be calculated by comparing mean ground- and surface-water elevations. Filtering methods traditionally used to determine daily mean sea level can be similarly applied to ground water to determine mean levels. Method (1) uses 71 consecutive hourly water-level observations to accurately determine the mean level. Method (2) approximates the mean level using only 25 consecutive hourly observations; however, there is a small error associated with this method.

  2. Ground-water flow and simulated effects of development in Paradise Valley, a basin tributary to the Humboldt River in Humboldt County, Nevada

    USGS Publications Warehouse

    Prudic, D.E.; Herman, M.E.

    1996-01-01

    A computer model was used to characterize ground-water flow in Paradise Valley, Nevada, and to evaluate probable long-term effects of five hypothetical development scenarios. One finding of the study is that concentrating pumping at the south end of Paradise Valley may increase underflow from the adjacent Humboldt River valley, and might affect flow in the river.

  3. Instream water use in the United States: water laws and methods for determining flow requirements

    USGS Publications Warehouse

    Lamb, Berton L.; Doerksen, Harvey R.

    1987-01-01

    Water use generally is divided into two primary classes - offstream use and instream use. In offstream use, sometimes called out-of-stream or diversionary use, water is withdrawn (diverted) from a stream or aquifer and transported to the place of use. Examples are irrigated agriculture, municipal water supply, and industrial use. Each of these offstream uses, which decreases the volume of water available downstream from the point of diversion, is discussed in previous articles in this volume. Instream use, which generally does not diminish the flow downstream from its point of use, and its importance are described in this article. One of the earliest instream uses of water in the United States was to turn the water wheels that powered much of the Nation's industry in the 18th and 19th centuries. Although a small volume of water might have been diverted to a mill near streamside, that water usually was returned to the stream near the point of diversion and, thus, the flow was not diminished downstream from the mill. Over time, the generation of hydroelectric power replaced mill wheels as a means of converting water flow into energy. Since the 1920's, the generation of hydroelectric power increasingly has become a major instream use of water. By 1985, more than 3 billion acre-feet of water (3,050,000 million gallons per day) was used annually for hydropower generation (Solley and others, 1988, p. 45)-enough water to cover the State of Colorado to a depth of 51 feet. Navigation is another instream use with a long history. The Lewis and Clark expedition journals and many of Mark Twain's novels illustrate the extent to which the Nation originally depended on adequate streamfiows for basic transportation. Navigation in the 1980's is still considered to be an instream use; however, it often is based upon a stream system that has been modified greatly through channelization, diking, and construction of dams and locks. The present (1987) inland water navigation system in

  4. Characterizing ground water flow in the municipal well fields of Cedar Rapids, Iowa, with selected environmental tracers

    USGS Publications Warehouse

    Boyd, R.A.

    1998-01-01

    Cedar Rapids obtains its municipal water supply from a shallow alluvial aquifer along the Cedar River in east-central Iowa. Water samples were collected and analyzed for selected isotopes and chlorofluorocarbons to characterize the ground-water flow system near the municipal well fields. Analyses of deuterium and oxygen-18 indicate that water in the alluvial aquifer and in the underlying carbonate bedrock aquifer was recharged from precipitation during modern climatic conditions. Analyses of tritium indicate modern, post-1952, water in the alluvial aquifer and older, pre-1952, water in the bedrock aquifer. Mixing of the modern and older waters occurs in areas where (1) the confining layer between the two aquifers is discontinuous, (2) the bedrock aquifer is fractured, or (3) pumping of supply wells induces the flow of water between aquifers. Analyses of chlorofluorocarbons were used to determine the date of recharge of water samples. Water in the bedrock aquifer likely was recharged prior to the 1950s. Water in the alluvial aquifer likely was recharged from the 1960s to 1990s. Biodegradation or sorption probably affected some of the ground water analyzed for chlorofluorocarbons. These processes reduce the concentrations of CFCs, which results in older than actual calculated dates of recharge.

  5. Evaluation of water cooled supersonic temperature and pressure probes for application to 2000 F flows

    NASA Technical Reports Server (NTRS)

    Lagen, Nicholas T.; Seiner, John M.

    1990-01-01

    The development of water cooled supersonic probes used to study high temperature jet plumes is addressed. These probes are: total pressure, static pressure, and total temperature. The motivation for these experiments is the determination of high temperature supersonic jet mean flow properties. A 3.54 inch exit diameter water cooled nozzle was used in the tests. It is designed for exit Mach 2 at 2000 F exit total temperature. Tests were conducted using water cooled probes capable of operating in Mach 2 flow, up to 2000 F total temperature. Of the two designs tested, an annular cooling method was chosen as superior. Data at the jet exit planes, and along the jet centerline, were obtained for total temperatures of 900 F, 1500 F, and 2000 F, for each of the probes. The data obtained from the total and static pressure probes are consistent with prior low temperature results. However, the data obtained from the total temperature probe was affected by the water coolant. The total temperature probe was tested up to 2000 F with, and without, the cooling system turned on to better understand the heat transfer process at the thermocouple bead. The rate of heat transfer across the thermocouple bead was greater when the coolant was turned on than when the coolant was turned off. This accounted for the lower temperature measurement by the cooled probe. The velocity and Mach number at the exit plane and centerline locations were determined from the Rayleigh-Pitot tube formula.

  6. Erosive dynamics of channels incised by subsurface water flow

    NASA Astrophysics Data System (ADS)

    Lobkovsky, Alexander E.; Smith, Braunen E.; Kudrolli, Arshad; Mohrig, David C.; Rothman, Daniel H.

    2007-09-01

    We propose a dynamical model for channels incised into an erodible bed by subsurface water flow. The model is validated by the time-resolved topographic measurements of channel growth in a laboratory-scale experiment. Surface heights in the experiment are measured via a novel laser-aided imaging technique. The erosion rate in the model is composed of diffusive and advective components as well as a simple driving term due to the seeping water. Steady driving conditions may exist whenever channels are incised into a flat and level erodible bed by a water table replenished via steady (on average) rainfall. Under such steady driving conditions, the model predicts an asymptotically self-similar growing shape for the channel transects. Conversely, given a transect shape that evolved under steady driving conditions and an estimate of the erosion rate at the bottom of the channel, granular transport coefficients can be inferred from the static channel shape. We report an estimate of these transport coefficients for a system of ravines incised into unconsolidated sand in the Apalachicola River basin, Florida.

  7. The inequality of water scarcity events: who is actually being affected?

    NASA Astrophysics Data System (ADS)

    Veldkamp, Ted I. E.; Wada, Yoshihide; Kummu, Matti; Aerts, Jeroen C. J. H.; Ward, Philip J.

    2015-04-01

    Over the past decades, changing hydro-climatic and socioeconomic conditions increased regional and global water scarcity problems. In the near future, projected changes in human water use and population growth - in combination with climate change - are expected to aggravate water scarcity conditions and its associated impacts on our society. Whilst a wide range of studies have modelled past and future regional and global patterns of change in population or land area impacted by water scarcity conditions, less attention is paid on who is actually affected and how vulnerable this share of the population is to water scarcity conditions. The actual impact of water scarcity events, however, not only depends on the numbers being affected, but merely on how sensitive this population is to water scarcity conditions, how quick and efficient governments can deal with the problems induced by water scarcity, and how many (financial and infrastructural) resources are available to cope with water scarce conditions. Only few studies have investigated the above mentioned interactions between societal composition and water scarcity conditions (e.g. by means of the social water scarcity index and the water poverty index) and, up to our knowledge, a comprehensive global analysis including different water scarcity indicators and multiple climate and socioeconomic scenarios is missing. To address this issue, we assess in this contribution the adaptive capacity of a society to water scarcity conditions, evaluate how this may be driven by different societal factors, and discuss how enhanced knowledge on this topic could be of interest for water managers in their design of adaptation strategies coping with water scarcity events. For that purpose, we couple spatial information on water scarcity conditions with different components from, among others, the Human Development Index and the Worldwide Governance Indicators, such as: the share of the population with an income below the poverty

  8. Integrated urban and rural water affairs management reform in China: Affecting factors

    NASA Astrophysics Data System (ADS)

    Shen, Dajun; Liu, Bin

    The institutional evolution is often induced by some factors. This paper intends to analyze the affecting factors in integrated urban and rural water affairs management reform in China. The integrated urban and rural water affairs management reform is to restructure the governmental organizational setting in water management by forms of water affair bureau or re-designing functions of current water resources bureau to incorporate part or all functions of resources management, service regulation and environment management in water sector. The analyses selected some natural and socio-economic factors. The results point out that the integrated urban and rural water affairs management reform is a factor-induced institutional evolution. The factors promoting this reform include occasional drought events, higher central water investment percentage; but the data from the urban sector do not provide the support to the reform.

  9. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.34 Waters subject to tidal...

  10. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.34 Waters subject to tidal...

  11. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.34 Waters subject to tidal...

  12. 33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water. 2.34 Section 2.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.34 Waters subject to tidal...

  13. Water flows, energy demand, and market analysis of the informal water sector in Kisumu, Kenya

    PubMed Central

    Sima, Laura C.; Kelner-Levine, Evan; Eckelman, Matthew J.; McCarty, Kathleen M.; Elimelech, Menachem

    2013-01-01

    In rapidly growing urban areas of developing countries, infrastructure has not been able to cope with population growth. Informal water businesses fulfill unmet water supply needs, yet little is understood about this sector. This paper presents data gathered from quantitative interviews with informal water business operators (n=260) in Kisumu, Kenya, collected during the dry season. Sales volume, location, resource use, and cost were analyzed by using material flow accounting and spatial analysis tools. Estimates show that over 76% of the city's water is consumed by less than 10% of the population who have water piped into their dwellings. The remainder of the population relies on a combination of water sources, including water purchased directly from kiosks (1.5 million m3 per day) and delivered by hand-drawn water-carts (0.75 million m3 per day). Energy audits were performed to compare energy use among various water sources in the city. Water delivery by truck is the highest per cubic meter energy demand (35 MJ/m3), while the city's tap water has the highest energy use overall (21,000 MJ/day). We group kiosks by neighborhood and compare sales volume and cost with neighborhood-level population data. Contrary to popular belief, we do not find evidence of price gouging; the lowest prices are charged in the highest-demand low-income area. We also see that the informal sector is sensitive to demand, as the number of private boreholes that serve as community water collection points are much larger where demand is greatest. PMID:23543887

  14. Testing research for oil-gas-water flow pattern in Daqing oilfield

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyan; Mao, Qianjun; Liu, Lijun; Xu, Ying; Chen, Wei

    2013-07-01

    During the period of the high water cut later stage, it is significant for decreasing energy consumption of gathering system to research oil-gas-water flow pattern. At the moment, the studies on oil-gas-water flow pattern are mainly focused on the temperature range of crude oil freezing point. A experimental system is designed, constructed and operated in oilfields in horizontal pipeline., which is used for experimental investigation and analysis of oil-gas-water flow pattern under freezing point in horizontal pipeline. According to the crude oil condition, the results show that oil-gas-water flow pattern includes four types that are oil contact wave flow, oil-oil particle dispersion flow, oil lamellar flow, oil puddle slugging flow.

  15. Complex network analysis of phase dynamics underlying oil-water two-phase flows.

    PubMed

    Gao, Zhong-Ke; Zhang, Shan-Shan; Cai, Qing; Yang, Yu-Xuan; Jin, Ning-De

    2016-01-01

    Characterizing the complicated flow behaviors arising from high water cut and low velocity oil-water flows is an important problem of significant challenge. We design a high-speed cycle motivation conductance sensor and carry out experiments for measuring the local flow information from different oil-in-water flow patterns. We first use multivariate time-frequency analysis to probe the typical features of three flow patterns from the perspective of energy and frequency. Then we infer complex networks from multi-channel measurements in terms of phase lag index, aiming to uncovering the phase dynamics governing the transition and evolution of different oil-in-water flow patterns. In particular, we employ spectral radius and weighted clustering coefficient entropy to characterize the derived unweighted and weighted networks and the results indicate that our approach yields quantitative insights into the phase dynamics underlying the high water cut and low velocity oil-water flows. PMID:27306101

  16. Complex network analysis of phase dynamics underlying oil-water two-phase flows

    PubMed Central

    Gao, Zhong-Ke; Zhang, Shan-Shan; Cai, Qing; Yang, Yu-Xuan; Jin, Ning-De

    2016-01-01

    Characterizing the complicated flow behaviors arising from high water cut and low velocity oil-water flows is an important problem of significant challenge. We design a high-speed cycle motivation conductance sensor and carry out experiments for measuring the local flow information from different oil-in-water flow patterns. We first use multivariate time-frequency analysis to probe the typical features of three flow patterns from the perspective of energy and frequency. Then we infer complex networks from multi-channel measurements in terms of phase lag index, aiming to uncovering the phase dynamics governing the transition and evolution of different oil-in-water flow patterns. In particular, we employ spectral radius and weighted clustering coefficient entropy to characterize the derived unweighted and weighted networks and the results indicate that our approach yields quantitative insights into the phase dynamics underlying the high water cut and low velocity oil-water flows. PMID:27306101

  17. Complex network analysis of phase dynamics underlying oil-water two-phase flows

    NASA Astrophysics Data System (ADS)

    Gao, Zhong-Ke; Zhang, Shan-Shan; Cai, Qing; Yang, Yu-Xuan; Jin, Ning-De

    2016-06-01

    Characterizing the complicated flow behaviors arising from high water cut and low velocity oil-water flows is an important problem of significant challenge. We design a high-speed cycle motivation conductance sensor and carry out experiments for measuring the local flow information from different oil-in-water flow patterns. We first use multivariate time-frequency analysis to probe the typical features of three flow patterns from the perspective of energy and frequency. Then we infer complex networks from multi-channel measurements in terms of phase lag index, aiming to uncovering the phase dynamics governing the transition and evolution of different oil-in-water flow patterns. In particular, we employ spectral radius and weighted clustering coefficient entropy to characterize the derived unweighted and weighted networks and the results indicate that our approach yields quantitative insights into the phase dynamics underlying the high water cut and low velocity oil-water flows.

  18. Soil water repellency affects production and transport of CO2 and CH4 in soil

    NASA Astrophysics Data System (ADS)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  19. Application of the Analogy Between Water Flow with a Free Surface and Two-dimensional Compressible Gas Flow

    NASA Technical Reports Server (NTRS)

    Orlin, W James; Lindner, Norman J; Bitterly, Jack G

    1947-01-01

    The theory of hydraulic analogy, that is, the analogy between water flow with a free surface and two-dimensional compressible gas flow and the limitations and conditions of the analogy are discussed. A test run was made using the hydraulic analogy as applied to the flow about circular cylinders at various diameters at subsonic velocities extending to the super critical range. The apparatus and techniques used in this application are described and criticized. Reasonably satisfactory agreement of pressure distributions and flow fields existed between water and airflow about corresponding bodies. This agreement indicated the possibility of extending experimental compressibility research by new methods.

  20. Interface evolution of a particle in a supersaturated solution affected by a far-field uniform flow

    NASA Astrophysics Data System (ADS)

    Chen, Ming-Wen; Wang, Zi-Dong

    2013-09-01

    The effect of far-field uniform flow on the morphological evolution of a spherical particle in a supersaturated solution affected by a far-field uniform flow is studied by using the matched asymptotic expansion method. The analytical solution for the interface shape, concentration field, and interface velocity of the particle growth shows that the convection induced by the far-field uniform flow facilitates the growth of the spherical particle, the upstream flow imposed on the particle enhances the growth velocity of the interface when the flow comes in, the downstream flow lowers the growth velocity of the surface when the flow goes out, and the interface morphology evolves into a peach-like shape.

  1. Predicting the impact of water demand and river flow regulation over riparian vegetation through mathematical modeling

    NASA Astrophysics Data System (ADS)

    Garcia-Arias, A.; Pons, C.; Frances, F.

    2013-12-01

    The vegetation of the riversides is a main part of the complex riparian ecosystems and has an important role maintaining the fluvial ecosystems. Biotic and abiotic interactions between the river and the riverbank are essential for the subsistence and the development of both ecosystems. In semi-arid Mediterranean areas, the riparian vegetation growth and distribution is especially controlled by the water accessibility, determining the limit between the lush riparian bands and the sparse upland. Human intervention can alter the river hydrology determining the riparian vegetation wellbeing and its distribution and, in consequence, affecting both riparian and fluvial ecosystems. Predictive models are necessary decision support tools for adequate river management and restoration initiatives. In this context, the RibAV model is useful to predict the impact of water demand and river flow regulation on the riparian vegetation. RibAV is able to reproduce the vegetation performance on the riverside allowing the scenarios analysis in terms of vegetation distribution and wellbeing. In this research several flow regulation and water demand scenarios are proposed and the impacts over three plant functional types (PFTs) are analyzed. The PFTs group the herbaceous riparian plants, the woody riparian plants and the terrestrial vegetation. The study site is the Terde reach at the Mijares River, a 539m length reach located in a semi-arid Mediterranean area in Spain. The scenarios represent river flow alterations required to attend different human demands. These demands encompass different seasonality, magnitude and location. The seasonality is represented as hydroelectric (constant all over the year), urban (increased during the summer period) and agricultural demands (monthly seasonality). The magnitude is varied considering the 20%, the 40% and the 80% of the mean daily flow. Two locations are considered, upstream or downstream the study site. To attend the demands located

  2. Flow of ices in the Ammonia-Water System

    NASA Technical Reports Server (NTRS)

    Durham, W. B.; Kirby, S. H.; Stern, L. A.

    1993-01-01

    We have fabricated in the laboratory and subsequently deformed crystalline hydrates and partial melts of the water-rich end of the NH3-H2O system, with the aim of improving our understanding of physical processes occurring in icy moons of the outer solar system. Deformation experiments were carried out at constant strain rate. The range of experimental variables are given. Phase relationships in the NH3-H2O system indicate that water ice and ammonia dihydrate, NH3-2H2O, are the stable phases under our experiment conditions. X-ray diffraction of our samples usually revealed these as the dominant phases, but we have also observed an amorphous phase (in unpressurized samples only) and occasionally significant ammonia monohydrate, NH3-H2O. The onset of partial melting at the peritectic temperature at about 176 K appeared as a sharp transition in strength observed in samples of x(sub NH3) = 0.05 and 0.01, the effect of melt was less pronounced. For any given water ice + dihydrate alloy in the subsolidus region, we observed one rheological law over the entire temperature range from 175 K to about 140 K. Below 140 K, a shear instability similar to that occurring in pure water ice under the same conditions limited our ability to measure ductile flow. The rheological laws for the several alloys vary systematically from that of pure ice to that of dihydrate. Pure dihydrate is about 4 orders of magnitude less viscous than water ice just below the peritectic temperature, but because of a very pronounced temperature dependence in dihydrate (100 kJ/mol versus 43 kJ/mol for water ice) the viscosity of dihydrate equals or exceeds that of water ice at T less than 140 K. The large variation in viscosity of dihydrate with relatively small changes in temperature may be helpful in explaining the rich variety of tectonic and volcanic features seen on the surfaces of icy moons in the outer solar system.

  3. Evaluation of an ultra low-flow water delivery system for small experimental tanks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An ultra low-flow water delivery system was developed and tested for use in research studies requiring low-flow in small water volumes. Small test systems save on the amount of fish, chemicals, and biologics needed in disease challenge and treatment experiments. The ultra low-flow system, comprise...

  4. Interfacial area measurement and transport modeling in air-water two-phase flow

    NASA Astrophysics Data System (ADS)

    Fu, Xinyu

    In two-fluid model, the interfacial area concentration (IAC) is an important parameter that characterizes the interaction of two-phases at the interface. The accuracy of IAC modeling and local measurements largely affects the efficiency of designing and assessing two-phase flow systems. The prediction of the dynamical evolution of IAC is one of the most challenging tasks in research and application. This thesis is focused on developing advanced local measurement techniques to obtain reliable two-phase parameters and implementing efficient theoretical models for IAC source and sink terms in a two-group interfacial area transport equation based on experiments. In this study, an advanced local measurement technique using a four-sensor conductivity probe has been presented for obtaining IAC in air-water flows. It extends the existing conductivity probe method to slug and churn-turbulent flows with a unified probe design and comprehensive signal processing system. Sophisticated algorithm and software have been implemented that is robust in handling most practical conditions with high reliability. Systematic analyses on the issues of probe applications and benchmarks have been performed. The improved four-sensor method has also been applied to flow conditions with significant local recirculation, which was considered the most challenging situation for local measurement in two-phase flow. Using the well-established instrumentation, solid databases for a two-inch air-water loop have been built with sufficient information on the axial development and the radial distribution of the local parameters. Mechanistic models of major fluid particle interaction phenomena involving two bubble groups have been proposed, including the shearing-off of small bubbles from slug/cap bubbles, the wake entrainment of group-1 bubble into group-2 bubble, the wake acceleration and coalescence between group-2 bubbles, and the breakup of group-2 bubbles due to surface instability. Prediction of

  5. Method and apparatus for affecting a recirculation zone in a cross flow

    DOEpatents

    Bathina, Mahesh; Singh, Ramanand

    2012-07-17

    Disclosed is a cross flow apparatus including a surface and at least one outlet located at the surface. The cross flow apparatus further includes at least one guide at the surface configured to direct an intersecting flow flowing across the surface and increase a velocity of a cross flow being expelled from the at least one outlet downstream from the at least one outlet.

  6. Water cut measurement of oil-water flow in vertical well by combining total flow rate and the response of a conductance probe

    NASA Astrophysics Data System (ADS)

    Chen, Jianjun; Xu, Lijun; Cao, Zhang; Zhang, Wen; Liu, Xingbin; Hu, Jinhai

    2015-09-01

    In this paper, a conductance probe-based well logging instrument was developed and the total flow rate is combined with the response of the conductance probe to estimate the water cut of the oil-water flow in a vertical well. The conductance probe records the time-varying electrical characteristics of the oil-water flow. Linear least squares regression (LSR) and nonlinear support vector regression (SVR) were used to establish models to map the total flow rate and features extracted from the probe response onto the water cut, respectively. Principal component analysis (PCA) and partial least squares analysis (PLSA) techniques were employed to reduce data redundancy within the extracted features. An experiment was carried out in a vertical pipe with an inner diameter of 125 mm and a height of 24 m in an experimental multi-phase flow setup, Daqing Oilfield, China. In the experiment, oil-water flow was used and the total flow rate varied from 10 to 200 m3 per day and the water cut varied from 0% to 100%. As a direct comparison, the cases were also studied when the total flow rate was not used as an independent input to the models. The results obtained demonstrate that: (1) the addition of the total flow rate as an input to the regression models can greatly improve the accuracy of water cut prediction, (2) the nonlinear SVR model performs much better than the linear LSR model, and (3) for the SVR model with the total flow rate as an input, the adoption of PCA or PLSA not only decreases the dimensions of inputs, but also increases prediction accuracy. The SVR model with five PCA-treated features plus the total flow rate achieves the best performance in water cut prediction, with a coefficient of determination (R2) as high as 0.9970. The corresponding root mean squared error (RMSE) and mean quoted error (MQE) are 0.0312% and 1.99%, respectively.

  7. Groundwater flow cycling between a submarine spring and an inland fresh water spring.

    PubMed

    Davis, J Hal; Verdi, Richard

    2014-01-01

    Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half. PMID:24138490

  8. Groundwater flow cycling between a submarine spring and an inland fresh water spring

    USGS Publications Warehouse

    Davis, J. Hal; Verdi, Richard

    2014-01-01

    Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half.

  9. Effects of rock fragments on water dynamics in a fire-affected soil

    NASA Astrophysics Data System (ADS)

    Gordillo-Rivero, Ángel J.; García-Moreno, Jorge; Jordán, Antonio; Zavala, Lorena M.

    2014-05-01

    Rock fragments (RF) are common in the surface of Mediterranean semiarid soils, and have important effects on the soil physical (bulk density and porosity) and hydrological processes (infiltration, evaporation, splash erosion and runoff generation) (Poesen and Lavee, 1994; Rieke-Zapp et al., 2007). In some cases, RFs in Mediterranean areas have been shown to protect bare soils from erosion risk (Cerdà, 2001; Martínez-Zavala, Jordán, 2008; Zavala et al., 2010). Some of these effects are much more relevant when vegetation cover is low or has been reduced after land use change or other causes, as forest fires. Although very few studies exist, the interest on the hydrological effects of RFs in burned areas is increasing recently. After a forest fire, RFs may contribute significantly to soil recovery. In this research we have studied the effect of surface and embedded RFs on soil water control, infiltration and evaporation in calcareous fire-affected soils from a Mediterranean area (SW Spain). For this study, we selected an area with soils derived from limestone under holm oak forest, recently affected by a moderate severity forest fire. The proportion of RF cover showed a significant positive relation with soil water-holding capacity and infiltration rates, although infiltration rate reduced significantly when RF cover increased above a certain threshold. Soil evaporation rate decreased with increasing volumetric content of RFs and became stable with RF contents approximately above 30%. Evaporation also decreased with increasing RF cover. When RF cover increased above 50%, no significant differences were observed between burned and control vegetated plots. REFERENCES Poesen, J., Lavee, H. 1994. Rock fragments in top soils: significance and processes. Catena Supplement 23, 1-28. Cerdà, A. 2001. Effect of rock fragment cover on soil infiltration, interrill runoff and erosion. European Journal of Soil Science 52, 59-68. DOI: 10.1046/j.1365-2389.2001.00354.x. Rieke

  10. Water flow controls distribution and feeding behavior of two co-occurring coral reef fishes: I. Field measurements

    NASA Astrophysics Data System (ADS)

    Finelli, C. M.; Clarke, R. D.; Robinson, H. E.; Buskey, E. J.

    2009-06-01

    The interaction of flowing water with reef topography creates a continuum of flow microhabitats that can alter species distributions directly via transport of organisms or propagules, or indirectly by modulating the availability of critical resources. To examine how water flow affects the distribution and feeding performance of two species of planktivorous tube blennies (Chaenopsidae), flow speed and turbulence were measured within the feeding areas of Acanthemblemaria spinosa and A. aspera at three sites within Glover’s Reef, Belize. Although co-occurring, A. spinosa occupies topographically high locations (e.g., upright coral skeletons) while A. aspera occupies topographically low shelters in the coral pavement. Boundary layer theory predicts that A. spinosa should experience higher flow (and a higher flux of planktonic food) relative to A. aspera; however, complex topography and oscillatory flow require that this prediction is tested directly in the field. Within each site, the flow experienced by A. spinosa was, indeed, faster and more turbulent than that experienced by A. aspera at site-specific intermediate wave heights. When waves were small, gentle velocity gradients produced similar flows for the two species. When waves were high, flow was uniformly fast through the water column due to thinning of the benthic boundary layer. Plankton availability was similar for the species, with the exception of a greater abundance of harpacticoid copepods at the shelters of A. aspera. Quantitative behavioral observations suggest that the foraging strategies employed by the two fishes exploit the prevailing hydrodynamic conditions. For example, A. spinosa, the stronger swimmer of the two, attacks nearly 100% of the time in the water column where it can exploit the higher flux of plankton associated with faster flows, while A. aspera attacks primarily toward the reef surface where currents are likely to be slower and it can exploit more abundant benthic prey.

  11. Is Brachial Artery Flow-Mediated Dilation Associated with Negative Affect?

    PubMed Central

    Kamarck, Thomas W.; Matthews, Karen A.; Brockwell, Sarah E.; Sutton-Tyrrell, Kim

    2010-01-01

    Background Trait negative affect has been implicated as a risk marker for cardiovascular disease, but the mechanisms underlying this association are uncertain. Purpose Our aim was to examine associations between trait measures of anger, hostility, depression, and anxiety with endothelial dysfunction via brachial artery flow-mediated dilation (FMD), an early indicator of cardiovascular disease. Method FMD was examined in 332 healthy older adults. Measures included Beck Anxiety and Depression Inventories, Cook–Medley Hostility Scale, and Spielberger State-Trait Anger Expression Inventory (Anger In, Anger Out, and Trait Anger). Results Mean age was 60.5±4.8 years; 83% of participants were Caucasian and 49% were female. FMD was greater in women compared to men (6.17% vs. 4.07%, p<0.001). Women reported significantly greater Anxiety (p<0.001), and men reported greater Hostility (p=0.004). In separate multivariable linear regression models controlling for cardiovascular risk factors, plus current hormone therapy for women, smaller FMD was associated with higher Anger In for women (β=− 0.222, p=0.04) and showed a trend with higher Hostility for men (β= −0.082, p=0.09). Conclusion Endothelial dysfunction, as indicated by less vasodilatation of the brachial artery, is positively associated with measures of hostility and anger suppression in healthy older adults. Thus, associations between negative affect and cardiovascular health may be apparent early in the disease process. PMID:19306064

  12. Water flow algorithm decision support tool for travelling salesman problem

    NASA Astrophysics Data System (ADS)

    Kamarudin, Anis Aklima; Othman, Zulaiha Ali; Sarim, Hafiz Mohd

    2016-08-01

    This paper discuss about the role of Decision Support Tool in Travelling Salesman Problem (TSP) for helping the researchers who doing research in same area will get the better result from the proposed algorithm. A study has been conducted and Rapid Application Development (RAD) model has been use as a methodology which includes requirement planning, user design, construction and cutover. Water Flow Algorithm (WFA) with initialization technique improvement is used as the proposed algorithm in this study for evaluating effectiveness against TSP cases. For DST evaluation will go through usability testing conducted on system use, quality of information, quality of interface and overall satisfaction. Evaluation is needed for determine whether this tool can assists user in making a decision to solve TSP problems with the proposed algorithm or not. Some statistical result shown the ability of this tool in term of helping researchers to conduct the experiments on the WFA with improvements TSP initialization.

  13. A system for calibrating seepage meters used to measure flow between ground water and surface water

    USGS Publications Warehouse

    Rosenberry, Donald O.; Menheer, Michael A.

    2006-01-01

    The in-line flowmeter used with this system is incapable of measuring seepage rates below about 7 centimeters per day. Smaller seepage rates can be measured manually. The seepage- control system also can be modified for measuring slower seepage rates with the use of two flowmeters and a slightly different water-routing system, or a fluid-metering pump can be used to control flow through the flux tank instead of an adjustable-height reservoir.

  14. FEWA: a Finite Element model of Water flow through Aquifers

    SciTech Connect

    Yeh, G.T.; Huff, D.D.

    1983-11-01

    This report documents the implementation and demonstration of a Finite Element model of Water flow through Aquifers (FEWA). The particular features of FEWA are its versatility and flexibility to deal with as many real-world problems as possible. Point as well as distributed sources/sinks are included to represent recharges/pumpings and rainfall infiltrations. All sources/sinks can be transient or steady state. Prescribed hydraulic head on the Dirichlet boundaries and fluxes on Neumann or Cauchy boundaries can be time-dependent or constant. Source/sink strength over each element and node, hydraulic head at each Dirichlet boundary node, and flux at each boundary segment can vary independently of each other. Either completely confined or completely unconfined aquifers, or partially confined and partially unconfined aquifers can be dealt with effectively. Discretization of a compound region with very irregular curved boundaries is made easy by including both quadrilateral and triangular elements in the formulation. Large-field problems can be solved efficiently by including a pointwise iterative solution strategy as an optional alternative to the direct elimination solution method for the matrix equation approximating the partial differential equation of groundwater flow. FEWA also includes transient flow through confining leaky aquifers lying above and/or below the aquifer of interest. The model is verified against three simple cases to which analytical solutions are available. It is then demonstrated by two examples of how the model can be applied to heterogeneous and anisotropic aquifers with transient boundary conditions, time-dependent sources/sinks, and confining aquitards for a confined aquifer of variable thickness and for a free surface problem in an unconfined aquifer, respectively. 20 references, 25 figures, 8 tables.

  15. Gas and liquid measurements in air-water bubbly flows

    SciTech Connect

    Zhou, X.; Doup, B.; Sun, X.

    2012-07-01

    Local measurements of gas- and liquid-phase flow parameters are conducted in an air-water two-phase flow loop. The test section is a vertical pipe with an inner diameter of 50 mm and a height of 3.2 m. The measurements are performed at z/D = 10. The gas-phase measurements are performed using a four-sensor conductivity probe. The data taken from this probe are processed using a signal processing program to yield radial profiles of the void fraction, bubble velocity, and interfacial area concentration. The velocity measurements of the liquid-phase are performed using a state-of-the-art Particle Image Velocimetry (PIV) system. The raw PIV images are acquired using fluorescent particles and an optical filtration device. Image processing is used to remove noise in the raw PIV images. The statistical cross correlation is introduced to determine the axial velocity field and turbulence intensity of the liquid-phase. Measurements are currently being performed at z/D = 32 to provide a more complete data set. These data can be used for computational fluid dynamic model development and validation. (authors)

  16. Flow loop studies with AMAX coal-water mixtures

    SciTech Connect

    Wildman, D.J.; Ekmann, J.M.

    1984-03-01

    The coal-water mixtures (CWM) with a stabilizer and the CWM without stabilizers were successfully transported through a flow loop facility under a variety of conditions. The handling characteristics of both CWM were reasonable. The mix tank mixer was not needed during nontesting hours to prevent settling of either material. After several days of transporting the nonstabilized material in the loop facility, the viscosity-reducing agent became ineffective. It was necessary to increase the concentration of the viscosity-reducing agent. The material with stabilizer could not be transported through the loop facility at mass flow rates greater than 209 lb/min until overnight shearing of the CWM in the tank. The CWM without a stabilizer appeared to be slightly shear-thickening, whereas the stabilized CWM initially exhibited shear-thinning behavior. The pressure losses measured for the nonstabilized material were similar to the pressure losses measured for CWM prepared at PETC with three or four percent higher concentration of Pittsburgh seam coal. Tests performed with the stabilized CWM experienced pressure losses similar to CWM prepared at PETC with Pittsburgh seam coal of five to seven percent higher concentration. Tests 1A, 2A, 1B, and 2B were not included in the comparison of in-house-prepared CWM due to differences in pretest handling procedures. 1 figure, 2 tables.

  17. Large-eddy simulations of unidirectional water flow over dunes

    NASA Astrophysics Data System (ADS)

    Grigoriadis, D. G. E.; Balaras, E.; Dimas, A. A.

    2009-06-01

    The unidirectional, subcritical flow over fixed dunes is studied numerically using large-eddy simulation, while the immersed boundary method is implemented to incorporate the bed geometry. Results are presented for a typical dune shape and two Reynolds numbers, Re = 17,500 and Re = 93,500, on the basis of bulk velocity and water depth. The numerical predictions of velocity statistics at the low Reynolds number are in very good agreement with available experimental data. A primary recirculation region develops downstream of the dune crest at both Reynolds numbers, while a secondary region develops at the toe of the dune crest only for the low Reynolds number. Downstream of the reattachment point, on the dune stoss, the turbulence intensity in the developing boundary layer is weaker than in comparable equilibrium boundary layers. Coherent vortical structures are identified using the fluctuating pressure field and the second invariant of the velocity gradient tensor. Vorticity is primarily generated at the dune crest in the form of spanwise "roller" structures. Roller structures dominate the flow dynamics near the crest, and are responsible for perturbing the boundary layer downstream of the reattachment point, which leads to the formation of "horseshoe" structures. Horseshoe structures dominate the near-wall dynamics after the reattachment point, do not rise to the free surface, and are distorted by the shear layer of the next crest. The occasional interaction between roller and horseshoe structures generates tube-like "kolk" structures, which rise to the free surface and persist for a long time before attenuating.

  18. Effects of virtual water flow on regional water resources stress: A case study of grain in China.

    PubMed

    Sun, Shikun; Wang, Yubao; Engel, Bernie A; Wu, Pute

    2016-04-15

    Scarcity of water resources is one of the major challenges in the world, particularly for the main water consumer, agriculture. Virtual water flow (VWF) promotes water redistribution geographically and provides a new solution for resolving regional water shortage and improving water use efficiency in the world. Virtual water transfer among regions will have a significant influence on the water systems in both grain export and import regions. In order to assess the impacts of VWF related grain transfer on regional water resources conditions, the study takes mainland China as study area for a comprehensive evaluation of virtual water flow on regional water resources stress. Results show that Northeast China and Huang-Huai-Hai region are the major grain production regions as well as the major virtual water export regions. National water savings related to grain VWF was about 58Gm(3), with 48Gm(3) blue water and 10Gm(3) green water. VWF changes the original water distribution and has a significant effect on water resources in both virtual water import and export regions. Grain VWF significantly increased water stress in grain export regions and alleviated water stress in grain import regions. Water stress index (WSI) of Heilongjiang and Inner Mongolia has been increased by 138% and 129% due to grain export. Stress from water shortages is generally severe in export regions, and issues with the sustainability of grain production and VWF pattern are worthy of further exploration. PMID:26851759

  19. How Green Water Flows structure be a decision indicator for ecological water allocation in arid Ejina Delta, China.

    NASA Astrophysics Data System (ADS)

    Yu, J.; Du, C.; Zhang, Y.; Liu, X.

    2014-12-01

    Green water flows, a key ecohydrological process, dominates the hydrological cycle in arid region. The structure of green water flows reflects the landscape water consumption characteristics and can be easily obtained by means of remote sensing approach. In arid region, limited fresh water and fragile environment resulted in sharp contradictions between economy and natural ecosystem concerning water demands. To rationally allocate economic and ecological water use, to maximize the regional freshwater use efficiency, is the route one must take for sustainable development in arid area. The pursuit of the most necessary ecological protection function and the maximum ecological water use efficiency is the key to ecological water allocation. However, we are short of simple and quick detectable variables or indexes to assess ecological water allocation decision. This paper introduced the green water flows structure as a decision variable, chose Heihe river flow allocation to downstream Ejina Delta for ecological protection as an example, put forward why and how green water flows structure could be used for ecological water allocation decision. The authors expect to provide reference for integrated fresh water resources management practice in arid region.

  20. Microbiology of Broiler Carcasses and Chemistry of Chiller Water as Affected by Water Reuse

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to determine the effects of treating and reusing poultry chiller water in a commercial poultry processing facility. Broiler carcasses and chiller water were obtained from a commercial processing facility which had recently installed a TOMCO Pathogen Management SystemJ to recyc...

  1. COSMOS soil water sensing affected by crop biomass and water status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water sensing methods are widely used to characterize water content in the root zone and below, but only a few are capable of sensing soil volumes larger than a few hundred liters. Scientists with the USDA-ARS Conservation & Production Research Laboratory, Bushland, Texas, evaluated: a) the Cos...

  2. Water use and water productivity of sugarbeet, malt barley and potato as affected by irrigation frequency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Successful irrigation management is one of the most important agronomic practices for achieving profitable yield and maximizing crop water productivity (CWP) while maintaining environmental quality by minimizing water losses to runoff and deep drainage. This study was conducted to compare the influe...

  3. Two-phase air-water stratified flow measurement using ultrasonic techniques

    SciTech Connect

    Fan, Shiwei; Yan, Tinghu; Yeung, Hoi

    2014-04-11

    In this paper, a time resolved ultrasound system was developed for investigating two-phase air-water stratified flow. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water flow and two-phase air-water stratified flow. For single phase water flow, the flow rates from ultrasound system were compared with those from electromagnetic flow (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase air-water stratified flow and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable.

  4. Analytical Model of Water Flow in Coal with Active Matrix

    NASA Astrophysics Data System (ADS)

    Siemek, Jakub; Stopa, Jerzy

    2014-12-01

    This paper presents new analytical model of gas-water flow in coal seams in one dimension with emphasis on interactions between water flowing in cleats and coal matrix. Coal as a flowing system, can be viewed as a solid organic material consisting of two flow subsystems: a microporous matrix and a system of interconnected macropores and fractures. Most of gas is accumulated in the microporous matrix, where the primary flow mechanism is diffusion. Fractures and cleats existing in coal play an important role as a transportation system for macro scale flow of water and gas governed by Darcy's law. The coal matrix can imbibe water under capillary forces leading to exchange of mass between fractures and coal matrix. In this paper new partial differential equation for water saturation in fractures has been formulated, respecting mass exchange between coal matrix and fractures. Exact analytical solution has been obtained using the method of characteristics. The final solution has very simple form that may be useful for practical engineering calculations. It was observed that the rate of exchange of mass between the fractures and the coal matrix is governed by an expression which is analogous to the Newton cooling law known from theory of heat exchange, but in present case the mass transfer coefficient depends not only on coal and fluid properties but also on time and position. The constant term of mass transfer coefficient depends on relation between micro porosity and macro porosity of coal, capillary forces, and microporous structure of coal matrix. This term can be expressed theoretically or obtained experimentally. W artykule zaprezentowano nowy model matematyczny przepływu wody i gazu w jednowymiarowej warstwie węglowej z uwzględnieniem wymiany masy między systemem szczelin i matrycą węglową. Węgiel jako system przepływowy traktowany jest jako układ o podwójnej porowatości i przepuszczalności, składający się z mikroporowatej matrycy węglowej oraz z

  5. THE SIGNIFICANCE OF "STAGNATION CURVES" FOR LEAD AND COPPER, AND WATER QUALITY FACTORS AFFECTING THEM

    EPA Science Inventory

    "Stagnation curves" are the response of metal levels, particularly lead and copper, to time under conditions of no water flow. Research on lead pipe in the early 1980's in the United States, Germany, and in the United Kingdom suggested that they were characterized by rapid incre...

  6. Water temperature in irrigation return flow from the Upper Snake Rock watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water returning to a river from an irrigated watershed could increase the water temperature in the river. The objective of this study was to compare the temperature of irrigation return flow water with the temperature of the diverted irrigation water. Water temperature was measured weekly in the mai...

  7. Steady convective flow in an unsaturated state dependent anisotropic soil profile: Analysis of the affected zone from a contaminating point source

    NASA Astrophysics Data System (ADS)

    Cohen, M.; Mualem, Y.

    2011-01-01

    SummaryAnisotropy of the medium plays a dominant role in shaping the flow pattern in the soil profile. This study analyses the effect of anisotropy on the horizontal spreading of the flow trajectories from a contaminating source point at the soil surface to a high water table. It considers a phreatic aquifer with infinite lateral extension and uniform sedimentary-layered soil profile, where a state dependent anisotropy factor (SDAF) - A( ψ), and Mualem's (1984) anisotropy model might be applicable. The numerically calculated streamlines portray the effect of anisotropy, and allow discernment among various anisotropic media. Different flow cases are analyzed with regard to their dependence on A( ψ), as well as their dependence on the infiltration rate, and on the orientation of the principal axes. Theory indicates that the flux direction is dependent on the capillary head and thus on the flow rate. Consequently, it is the infiltration rate, which determines the particular path line from the contaminant source point to the ground water table. Accordingly, we have defined the "affected domain" as the domain within the unsaturated profile which is vulnerable to contamination from a source point at the soil surface, and the "affected segment" as the segment on the phreatic surface where pollutants may potentially reach the ground water aquifer. Both are determined with respect to anisotropy, infiltration rate, and depth. The non-linear horizontal shift of the contaminant trajectory indicates that a substantial error may result when adopting a constant anisotropy factor. This study suggests that the maximal horizontal shift is the relevant scale when characterizing the anisotropic flow system. This measure should be taken into consideration when designing a related laboratory experiment or a field monitoring system.

  8. Permeameter studies of water flow through cement and clay borehole seals in granite, basalt and tuff

    SciTech Connect

    South, D.L.; Daemen, J.J.K.

    1986-10-01

    Boreholes near a repository must be sealed to prevent rapid migration of radionuclide-contaminated water to the accessible environment. The objective of this research is to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. Flow through a sealed borehole is compared with flow through intact rock. Cement or bentonite seals have been tested in granite, basalt, and welded tuff. The main conclusion is that under laboratory conditions, existing commercial materials can form high quality seals. Triaxial stress changes about a borehole do not significantly affect seal performance if the rock is stiffer than the seal. Temperature but especially moisture variations (drying) significantly degrade the quality of cement seals. Performance partially recovers upon resaturation. A skillfully sealed borehole may be as impermeable as the host rock. Analysis of the influence of relative seal-rock permeabilities shows that a plug with permeability one order of magnitude greater than that of the rock results in a flow increase through the hole and surrounding rock of only 1-1/2 times compared to the undisturbed rock. Since a borehole is only a small part of the total rock mass, the total effect is even less pronounced. The simplest and most effective way to decrease flow through a rock-seal system is to increase the seal length, assuming it can be guaranteed that no dominant by-pass flowpath through the rock exists.

  9. Visualization by light transmission of oil and water contents in transient two-phase flow fields

    NASA Astrophysics Data System (ADS)

    Darnault, Christophe J. G.; Throop, James A.; DiCarlo, David A.; Rimmer, Alon; Steenhuis, Tammo S.; Parlange, J.-Yves

    1998-06-01

    The difficulty of determining transient fluid contents in a soil-oil-water system is hampering an understanding of the system's flow characteristics. In this paper, we describe a light transmission method (LTM) which can rapidly obtain oil and water contents throughout a large two-dimensional flow field of silica sand. By appropriately coloring the water with 0.005% FD&C blue #1, the hue of the transmitted light is found to be directly related to the water content within the porous media. The hue provides a high resolution measurement of the water and oil contents in transient flow fields (such as unstable flow). Evaluation of the reliability of LTM was assessed by checking the mass balance for a known water injection and its utility in visualizing a whole flow field was exemplified for unstable fingered flow by comparing fluid contents to those obtained with synchrotron X-ray radiation.

  10. Monitoring water quality alteration in River Tagus (Spain) after implementing temporal and spatial flow regulations at the head basin during the last century

    NASA Astrophysics Data System (ADS)

    Gascó, Antonio; de la Fuente, Javier; Hermosilla, Daphne

    2013-04-01

    Water resources quality is a wide concept accepting different meanings, from the composition and properties of the water dissolution to the diversity of priority uses (e.g. human consumption, ecological or urban-industrial); and it may anyhow be affected by both natural and artificial causes. Particularly, natural water flows may be artificially regulated in time (reservoirs) and space (transfers) in order to raise water availability; so flow regulations may also affect natural water properties. Even though regulation by reservoirs may even produce a better water quality because ombrogenic water (winter rain) is greatly predominant over pedogenic (drainage through soil) and lithogenic (spring forth aquifers) ones in the flow configuration; regulation by transfers is expected to mainly affect water quality in the middle river basin via a greater mineralization of the water flowing through the course. Particularly, Entrepeñas (803 hm3) and Buendía (1639 hm3) reservoirs, closed in 1956 and 1957 at the head of River Tagus' basin, respectively, plus Bolarque dam (31 hm3), built in 1910, make up the temporal regulation system that makes possible the transfer from River Tagus to River Segura, which has been designed for a flow of 33 m3•s-1, and a future maximum transfer forecast of 1000 hm3•year-1 (600 granted). In short, this assessment essay shows how these temporal and spatial regulations at the head of River Tagus have affected water quality downstream. In order to achieve this scope assessing water quality figures, a sampling point located upstream Aranjuez (Madrid, Spain) was chosen from those belonging to River Tagus' water quality integral network; so water quality would neither be affected by wastewater from big cities such as Madrid, Alcalá de Henares, and Guadalajara. Available data for three timely considered time periods were considered: (1) before temporal regulation through reservoirs was performed (1942); (2) after temporal regulation was fully

  11. Effects of macro-pores on water flow in coastal subsurface drainage systems

    NASA Astrophysics Data System (ADS)

    Xin, Pei; Yu, Xiayang; Lu, Chunhui; Li, Ling

    2016-01-01

    Leaching through subsurface drainage systems has been widely adopted to ameliorate saline soils. The application of this method to remove salt from reclaimed lands in the coastal zone, however, may be impacted by macro-pores such as crab burrows, which are commonly distributed in the soils. We developed a three-dimensional model to investigate water flow in subsurface drainage systems affected by macro-pores distributed deterministically and randomly through Monte Carlo simulations. The results showed that, for subsurface drainage systems under the condition of continuous surface ponding, macro-pores increased the hydraulic head in the deep soil, which in turn reduced the hydraulic gradient between the surface and deep soil. As a consequence, water infiltration across the soil surface was inhibited. Since salt transport in the soil is dominated by advection, the flow simulation results indicated that macro-pores decreased the efficiency of salt leaching by one order of magnitude, in terms of both the elapsed time and the amount of water required to remove salt over the designed soil leaching depth (0.6 m). The reduction of the leaching efficiency was even greater in drainage systems with a layered soil stratigraphy. Sensitivity analyses demonstrated that with an increased penetration depth or density of macro-pores, the leaching efficiency decreased further. The revealed impact of macro-pores on water flow represents a significant shortcoming of the salt leaching technique when applied to coastal saline soils. Future designs of soil amelioration schemes in the coastal zone should consider and aim to minimize the bypassing effect caused by macro-pores.

  12. Historical development of crop-related water footprints and inter-regional virtual water flows within China

    NASA Astrophysics Data System (ADS)

    Zhuo, La; Mekonnen, Mesfin M.; Hoekstra, Arjen Y.

    2015-04-01

    China is facing water-related challenges, including an uneven distribution of water resources, both temporally and spatially, and an increasing competition over the limited water resources among different sectors. This issue has been widely researched and was finally included into the National Plan 2011 (the 2011 No. 1 Document by the State Council of China). However, there is still lack of information on how population growth and rapid urbanization have affected the water resources in China over the last decades. The current study aims at investigating (i) the intra-annual variation of green and blue water footprints (WFs) of crop production in China over the period 1978-2009 at a spatial resolution of 5 by 5 arc-minute; (ii) the yearly virtual water (VW) balances of 31 provinces within China, related water savings for the country, as well as the VW flows among eight economic regions resulting from inter-regional crop trade over the same period; and (iii) the development of the WF related to crop consumption by Chinese consumers. Results show that, over the period 1978-2009, the total WF related to crop production within China increased by only 4%), but regional changes were significant. From the 1980s to the 2000s, the shift of the cropping centre from the South to the North resulted in an increase of about 16% in the blue WF and 19% in the green WF in the North and a reduction of the blue and green WF in the South by 11% and 3%, respectively. China as a whole was a net virtual water importer related to crop trade, thus saving domestic water resources. China's inter-regional crop trade generated a blue water 'loss' annually by transferring crops from provinces with relatively low crop water productivity to provinces with relatively high productivity. Over the decades, the original VW flow from the South coastal region to the Northeast was reversed. Rice was the all-time dominant crop in the inter-regional VW flows (accounting for 34% in 2009), followed by wheat

  13. Systematics of Water Temperature and Flow at Tantalus Creek During Calendar Year 2005, Norris Geyser Basin, Yellowstone National Park, Wyoming

    USGS Publications Warehouse

    Clor, Laura E.; Lowenstern, Jacob B.; Heasler, Henry P.

    2007-01-01

    We analyze data for stream flow and water temperature from Tantalus Creek in the Norris Geyser Basin and their relationship to air temperature, precipitation, and geyser eruptions during calendar year 2005. The creek is of interest because it is the primary drainage of the Norris Geyser Basin and carries a very high proportion of thermal water derived directly from hot springs. Two separate diurnal patterns emerge - (1) a winter pattern where increases in water temperature and stream flow closely track those of air temperature and (2) a summer pattern where water and air temperature are closely aligned but stream flow declines once water temperature reaches its daily maximum. The winter pattern is present when the daily average temperature consistently drops below 0 ?C whereas the summer pattern is recognizable when the daily average temperature regularly exceeds 0 ?C. Spring and fall systematics are much more irregular, although both summer and winter patterns can be discerned occasionally during those seasons. We interpret increases in stream flow associated with the winter pattern to result from addition of locally sourced melt water (both snow and soil-bound ice) that increases in abundance once temperatures increase in the morning. Melting is facilitated by the warm ground temperatures in the geyser basin, which are significantly higher than air temperatures in the winter. The summer pattern appears to be strongly affected by increased evaporation in the afternoon, decreasing flow and cooling the remaining water. Discharge from eruptions at Echinus Geyser are clearly visible as peaks in the hydrograph, and indicate that water from this geyser reach the Tantalus weir in 80 to 90 minutes, reflecting a slug of water that travels about 0.4 m s-1.

  14. WATER QUALITY IN THE NEAR COASTAL WATERS OF THE GULF OF MEXICO AFFECTED BY HURRICANE KATRINA: BEFORE AND AFTER THE STORM

    EPA Science Inventory

    Water quality was assessed following Hurricane Katrina in the affected waters of Alabama, Mississippi and Louisiana. Post-landfall water quality was compared to pre-hurricane conditions using indicators assessed by EPA's National Coastal Assessment program and additional indicat...

  15. Exploring the link between soil permeability, overland flow generation and land use and its effect on water flow paths in the humid tropics

    NASA Astrophysics Data System (ADS)

    Hassler, S. K.; Ogden, F. L.; Elsenbeer, H.; Crouch, T. D.

    2011-12-01

    In some parts of the humid tropics, overland flow (OF) is a main driver of erosion and nutrient depletion of soils. Its occurrence on hillslopes is frequently estimated by examining permeability (Ks) changes with depth in relation to prevailing rainfall intensities: a pronounced decrease may result in surface saturation due to perched water tables, and hence in saturation-excess OF. The precise relationship between Ks characteristics, the resulting water flow paths and hence OF occurrence, however, is poorly documented, especially for sites undergoing a land cover change. We studied three sites in central Panama, a 5 year-old secondary forest, a 25 year-old secondary forest and an adjacent teak plantation. OF occurrence was monitored on five, four and two 30 x 30 m planar plots, respectively, and in flow lines. We determined permeability at the depths of 0-6 cm and 6-12 cm on undisturbed soil cores from these plots. We also estimated vegetation parameters and soil texture on the plots. Comparison of rainfall intensities, Ks values and OF occurrence showed differences between the sites and between plots and flow lines. Despite very low Ks values, less OF occurred on the 5 year-old forest plots than on the 25 year-old forest plots with higher Ks values. However, flow lines in the younger forest produced more OF than in the older forest. This suggests the generation of saturation-excess overland flow in the older forest and lateral subsurface flow towards the flow lines in the younger forest. Ks in the teak plantation was much more variable than in the forests. Especially at the lower sampling depth it included higher Ks values, likely permitting more vertical water movement compared to the forest sites. Accordingly, the OF response in the flow lines was less. We conclude that simple comparisons between rainfall intensities and Ks are not sufficient to estimate OF occurrence because local water flow paths might be affected by additional factors such as vegetation

  16. Isolation of the combined water content and salinity effects on ERT measurement to locate the preferential flow pathways in water repellent soils

    NASA Astrophysics Data System (ADS)

    Brindt, Naaran; Rahav, Matan; Furman, Alex; Wallach, Rony

    2016-04-01

    Electrical resistivity tomography (ERT) has been used for measuring the dynamics of water flow in soils without disturbing the soil, and recently for identifying the preferential flow pathways that are reported to develop in water repellent soils. Since electrical resistivity is affected mainly by soil saturation and salinity, and given that in many cases salinity in the root zone reaches high values, the isolation of spatial and temporal distribution of water content or salinity in the root zone from ERT scans is a challenge. A model for transient variation of soil water content and salinity within a well-mixed soil unit was developed in the frame of this challenge. The model aims to isolate the temporal changes in water content from subsequent ERT scans. The model assumes that four stages of water dynamics occur in the root zone during an irrigation cycle: 1) Soil water content decreases by evapotranspiration - no irrigation, 2) Irrigation with saline water begins, water content increases but remains below field capacity - negligible drainage, 3) Irrigation continues and drainage starts as the water content becomes higher than field capacity, and 4) Irrigation stops, water content is higher than field capacity, and water content decreases by drainage and evapotranspiration. These four stages restart when drainage stops and water content decreases solely by evapotranspiration. The model was solved analytically and successfully applied to a series of sequential ERT scans accomplished during and between subsequent irrigation events for a soil that was rendered hydrophobic by olive trees irrigated with saline water, and a soil in a citrus orchard that was rendered hydrophobic by prolonged effluent irrigation. The suggested model helps in distinguishing between the temporal changes in water content and salinity within a given soil volume, locating the preferential plow pathways, and tracking the spatial and temporal salinity variation within the root zone during and

  17. Analysis and simulation of ground-water flow in Lake Wales Ridge and adjacent areas of central Florida

    USGS Publications Warehouse

    Yobbi, Dann K.

    1996-01-01

    final test of model calibration was conducted by successfully simulating transient conditions for the period October 1988 through September 1989. Altitudes of the water table, base of the surficial aquifer, riverbed conductances, confining-unit leakances, aquifer transmissivities, and net recharge and discharge rates were determine during calibration. Steady- state and transient simulations reasonably approximated measured aquifer heads and lake levels. Residuals were within the established calibration criteria that required 68 percent of all simulated heads to be within + - 2 feet of observed surficial aquifer heads and lake levels and + - 5 feet of observed intermediate and Upper Floridan aquifer heads. Simulation of streamflow was poor, probably due to the scale of the model and regulated streamflow conditions. Simulation indicates a marked difference between the ground-water flow rates of September 1989 (steady-state conditions, end of wet season) and May 1990 (large pumpage, end of dry season) in million gallons per day: September May 1989 1990 Pumping rate 126 486 Donward leakage (into 367 564 Upper Floridan aquifer) Streamflow 67 13 Net lateral boundary flow 218 115 Total discharge (excluding 479 626 evapotranspiration The calibrated flow model was used to simulate the short-term (one year) effects of 1990 water year pumpage (349 Mgal/d) on the September 1989 ground- water flow system in response to five different pumping schemes: (2) no pumpage, (2) no public supply pumpage, (3) no industrial pumpage, (4) no agricultural pumpage, and (5) no regional pumping outside the Water Use Caution Area. Simulation of no pumpage indicated maximum aquifer head rises of about 2 feet in the surficial aquifer and lakes, about 12 feet in the intermediate aquifer and about 16 feet in the Upper Floridan aquifer. The high rate recharge areas along the Lake Wales Ridge are most affect

  18. Experimenting with Water. Factors Affecting the Solubility of Substances in Water.

    ERIC Educational Resources Information Center

    Bourgeois, Simone P.; And Others

    1986-01-01

    Presents a module that focuses on the solvent property of water. Indicates the knowledge items, skills, processes, and attitudes that are developed in the unit. Includes background information as well as student directions for an experiment on solubility. (ML)

  19. Left ventricular end-diastolic pressure affects measurement of fractional flow reserve

    PubMed Central

    Leonardi, Robert A.; Townsend, Jacob C.; Patel, Chetan A.; Wolf, Bethany J.; Todoran, Thomas M.; Fernandes, Valerian L.; Nielsen, Christopher D.; Steinberg, Daniel H.; Powers, Eric R.

    2013-01-01

    Background Fractional flow reserve (FFR), the hyperemic ratio of distal (Pd) to proximal (Pa) coronary pressure, is used to identify the need for coronary revascularization. Changes in left ventricular end-diastolic pressure (LVEDP) might affect measurements of FFR. Methods and Materials LVEDP was recorded simultaneously with Pd and Pa during conventional FFR measurement as well as during additional infusion of nitroprusside. The relationship between LVEDP, Pa, and FFR was assessed using linear mixed models. Results Prospectively collected data for 528 cardiac cycles from 20 coronary arteries in 17 patients were analyzed. Baseline median Pa, Pd, FFR, and LVEDP were 73 mmHg, 49 mmHg, 0.69, and 18 mmHg, respectively. FFR < 0.80 was present in 14 arteries (70%). With nitroprusside median Pa, Pd, FFR, and LVEDP were 61 mmHg, 42 mmHg, 0.68, and 12 mmHg, respectively. In a multivariable model for the entire population LVEDP was positively associated with FFR such that FFR increased by 0.008 for every 1-mmHg increase in LVEDP (beta = 0.008; P < 0.001), an association that was greater in obstructed arteries with FFR < 0.80 (beta = 0.01; P < 0.001). Pa did not directly affect FFR in the multivariable model, but an interaction between LVEDP and Pa determined that LVEDP’s effect on FFR is greater at lower Pa. Conclusions LVEDP was positively associated with FFR. The association was greater in obstructive disease (FFR < 0.80) and at lower Pa. These findings have implications for the use of FFR to guide revascularization in patients with heart failure. Summary for Annotated Table of Contents The impact of left ventricular diastolic pressure on measurement of fractional flow reserve (FFR) is not well described. We present a hemodynamic study of the issue, concluding that increasing left ventricular diastolic pressure can increase measurements of FFR, particularly in patients with FFR < 0.80 and lower blood pressure. PMID:23886870

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

    SciTech Connect

    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.

  1. Performance of a cross-flow humidifier with a high flux water vapor transport membrane

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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.

  2. Factors Affecting the Growth Behavior of De-lonized Water Assisted Carbon Nanotube Forests.

    PubMed

    Adusumilli, Siva P; Westgate, Charles R

    2015-09-01

    The aim of this work is to analyze the conditions for producing water assisted carbon nanotubes (WA-CNT) forests by varying parameters that include growth temperature; de-ionized (DI) water flow; carbon-containing gas flow; and thereby determine the length, impurities and catalyst utilization in the CNT forest. Most importantly, the impact of water molecules on the length and catalyst utilization of the CNT forest was investigated. The CNT forests with lengths up to 140 microns were grown using a chemical vapor deposition technique at atmospheric pressure. The forest bundles had weak adhesion with the substrate which allows them to be peeled off easily, enabling easy transfer to other substrates. The characterization of CNT forest were carried out using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscopy (HR-TEM) techniques. PMID:26716218

  3. Distribution System Water Quality Affects Responses of Opportunistic Pathogen Gene Markers in Household Water Heaters.

    PubMed

    Wang, Hong; Masters, Sheldon; Falkinham, Joseph O; Edwards, Marc A; Pruden, Amy

    2015-07-21

    Illustrative distribution system operation and management practices shaped the occurrence and persistence of Legionella spp., nontuberculous mycobacteria (NTM), Pseudomonas aeruginosa, and two amoebae host (Acanthamoeba spp., Vermamoeba vermiformis) gene markers in the effluent of standardized simulated household water heaters (SWHs). The interplay between disinfectant type (chlorine or chloramine), water age (2.3-5.7 days) and materials (polyvinyl chloride (PVC), cement or iron) in upstream simulated distribution systems (SDSs) profoundly influenced levels of pathogen gene markers in corresponding SWH bulk waters. For example, Legionella spp. were 3-4 log higher in SWHs receiving water from chloraminated vs chlorinated SDSs, because of disinfectant decay from nitrification. By contrast, SWHs fed with chlorinated PVC SDS water not only harbored the lowest levels of all pathogen markers, but effluent from the chlorinated SWHs were even lower than influent levels in several instances (e.g., 2 log less Legionella spp. and NTM for PVC and 3-5 log less P. aeruginosa for cement). However, pathogen gene marker influent levels correlated positively to effluent levels in the SWHs (P < 0.05). Likewise, microbial community structures were similar between SWHs and the corresponding SDS feed waters. This study highlights the importance and challenges of distribution system management/operation to help control opportunistic pathogens. PMID:26121595

  4. Ultrasonic method for measuring water holdup of low velocity and high-water-cut oil-water two-phase flow

    NASA Astrophysics Data System (ADS)

    Zhao, An; Han, Yun-Feng; Ren, Ying-Yu; Zhai, Lu-Sheng; in, Ning-De

    2016-03-01

    Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China's onshore oil fields are mostly in the high-water-cut production stage. This stage is associated with severely non-uniform local-velocity flow profiles and dispersed-phase concentration (of oil droplets) in oil-water two-phase flow, which makes it difficult to measure water holdup in oil wells. In this study, we use an ultrasonic method based on a transmission-type sensor in oil-water two-phase flow to measure water holdup in low-velocity and high water-cut conditions. First, we optimize the excitation frequency of the ultrasonic sensor by calculating the sensitivity of the ultrasonic field using the finite element method for multiphysics coupling. Then we calculate the change trend of sound pressure level attenuation ratio with the increase in oil holdup to verify the feasibility of the employed diameter for the ultrasonic sensor. Based on the results, we then investigate the effects of oil-droplet diameter and distribution on the ultrasonic field. To further understand the measurement characteristics of the ultrasonic sensor, we perform a flow loop test on vertical upward oil-water two-phase flow and measure the responses of the optimized ultrasonic sensor. The results show that the ultrasonic sensor yields poor resolution for a dispersed oil slug in water flow (D OS/W flow), but the resolution is favorable for dispersed oil in water flow (D O/W flow) and very fine dispersed oil in water flow (VFD O/W flow). This research demonstrates the potential application of a pulsed-transmission ultrasonic method for measuring the fraction of individual components in oil-water two-phase flow with a low mixture velocity and high water cut.

  5. Flow enhances photosynthesis in marine benthic autotrophs by increasing the efflux of oxygen from the organism to the water

    PubMed Central

    Mass, Tali; Genin, Amatzia; Shavit, Uri; Grinstein, Mor; Tchernov, Dan

    2010-01-01

    Worldwide, many marine coastal habitats are facing rapid deterioration due in part to human-driven changes in habitat characteristics, including changes in flow patterns, a factor known to greatly affect primary production in corals, algae, and seagrasses. The effect of flow traditionally is attributed to enhanced influx of nutrients and dissolved inorganic carbon (DIC) across the benthic boundary layer from the water to the organism however, here we report that the organism’s photosynthetic response to changes in the flow is nearly instantaneous, and that neither nutrients nor DIC limits this rapid response. Using microelectrodes, dual-pulse amplitude-modulated fluorometry, particle image velocimetry, and real time mass-spectrometry with the common scleractinian coral Favia veroni, the alga Gracilaria cornea, and the seagrass Halophila stipulacea, we show that this augmented photosynthesis is due to flow-driven enhancement of oxygen efflux from the organism to the water, which increases the affinity of the RuBisCO to CO2. No augmentation of photosynthesis was found in the absence of flow or when flow occurred, but the ambient concentration of oxygen was artificially elevated. We suggest that water motion should be considered a fundamental factor, equivalent to light and nutrients, in determining photosynthesis rates in marine benthic autotrophs. PMID:20133799

  6. Recent (2003-05) Water Quality of Barton Springs, Austin, Texas, With Emphasis on Factors Affecting Variability

    USGS Publications Warehouse

    Mahler, Barbara J.; Garner, Bradley D.; Musgrove, MaryLynn; Guilfoyle, Amber L.; Rao, Mohan V.

    2006-01-01

    From 2003 to 2005, the U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, collected and analyzed water samples from the four springs (orifices) of Barton Springs in Austin, Texas (Upper, Main, Eliza, and Old Mill Springs), with the objective of characterizing water quality. Barton Springs is the major discharge point for the Barton Springs segment of the Edwards aquifer. A three-pronged sampling approach was used: physicochemical properties (including specific conductance and turbidity) were measured continuously; samples were collected from the four springs routinely every 2 weeks (during August-September 2003) to 3 weeks (during June 2004-June 2005) and analyzed for some or all major ions, nutrients, trace elements, soluble pesticides, and volatile organic compounds; and samples were collected from the four springs at more closely spaced intervals during the 2 weeks following two storms and analyzed for the same suite of constituents. Following the two storms, samples also were collected from five of the six major streams that provide recharge to Barton Springs. Spring discharge during both sample collection periods was above average (60 cubic feet per second or greater). Barton Springs was found to be affected by persistent low concentrations of atrazine (an herbicide), chloroform (a drinking-water disinfection by-product), and tetrachloroethene (a solvent). Increased recharge from the major recharging streams resulted in increased calcium, sulfate, atrazine, simazine, and tetrachloroethene concentrations and decreased concentrations of most other major ions, nitrate, and chloroform at one or more of the springs. These changes in concentration demonstrate the influence of water quality in recharging streams on water quality at the springs even during non-stormflow conditions. The geochemical compositions of the four springs indicate that Upper Spring is more contaminated and is influenced by a contributing flow path that

  7. Construction of estimated flow- and load-duration curves for Kentucky using the Water Availability Tool for Environmental Resources (WATER)

    USGS Publications Warehouse

    Unthank, Michael D.; Newson, Jeremy K.; Williamson, Tanja N.; Nelson, Hugh L.

    2012-01-01

    Flow- and load-duration curves were constructed from the model outputs of the U.S. Geological Survey's Water Availability Tool for Environmental Resources (WATER) application for streams in Kentucky. The WATER application was designed to access multiple geospatial datasets to generate more than 60 years of statistically based streamflow data for Kentucky. The WATER application enables a user to graphically select a site on a stream and generate an estimated hydrograph and flow-duration curve for the watershed upstream of that point. The flow-duration curves are constructed by calculating the exceedance probability of the modeled daily streamflows. User-defined water-quality criteria and (or) sampling results can be loaded into the WATER application to construct load-duration curves that are based on the modeled streamflow results. Estimates of flow and streamflow statistics were derived from TOPographically Based Hydrological MODEL (TOPMODEL) simulations in the WATER application. A modified TOPMODEL code, SDP-TOPMODEL (Sinkhole Drainage Process-TOPMODEL) was used to simulate daily mean discharges over the period of record for 5 karst and 5 non-karst watersheds in Kentucky in order to verify the calibrated model. A statistical evaluation of the model's verification simulations show that calibration criteria, established by previous WATER application reports, were met thus insuring the model's ability to provide acceptably accurate estimates of discharge at gaged and ungaged sites throughout Kentucky. Flow-duration curves are constructed in the WATER application by calculating the exceedence probability of the modeled daily flow values. The flow-duration intervals are expressed as a percentage, with zero corresponding to the highest stream discharge in the streamflow record. Load-duration curves are constructed by applying the loading equation (Load = Flow*Water-quality criterion) at each flow interval.

  8. Approximate solutions for Forchheimer flow during water injection and water production in an unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Mathias, Simon A.; Moutsopoulos, Konstantinos N.

    2016-07-01

    Understanding the hydraulics around injection and production wells in unconfined aquifers associated with rainwater and reclaimed water aquifer storage schemes is an issue of increasing importance. Much work has been done previously to understand the mathematics associated with Darcy's law in this context. However, groundwater flow velocities around injection and production wells are likely to be sufficiently large such as to induce significant non-Darcy effects. This article presents a mathematical analysis to look at Forchheimer's equation in the context of water injection and water production in unconfined aquifers. Three different approximate solutions are derived using quasi-steady-state assumptions and the method of matched asymptotic expansion. The resulting approximate solutions are shown to be accurate for a wide range of practical scenarios by comparison with a finite difference solution to the full problem of concern. The approximate solutions have led to an improved understanding of the flow dynamics. They can also be used as verification tools for future numerical models in this context.

  9. Investigation of statistical parameters of turbulent air flow over waved water surface by direct numerical simulation

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Druzhinin, Oleg

    2013-04-01

    Interaction of surface water waves with the wind flow is of primary importance for the wave modeling. The most difficult case for modeling is that of steep waves, when the strongly non-linear effects (e.g. sheltering, flow separation, vortex formation etc.) are encountered in the airflow over waves. Of special interest is also the influence of the wind flow stratification on the wind-wave interaction. In this work the preliminary results of direct numerical simulation (DNS)of structure and statistical characteristics of a turbulent, stably stratified atmospheric boundary layer over waved water surface are presented. In the experiments two-dimensional water waves with different wave age parameters (c/u* = 0-10, where u* is the friction velocity and c is the wave celerity), wave slope ka = 0-0.2 and at a bulk Reynolds number Re = 15000 and different values of the bulk Richardson number Ri (based on the buoyancy jump, bulk velocity and the surface wave length) are considered. The shape of the water wave is prescribed and does not evolve under the action of the wind. The full, 3D Navier-Stokes equations under the Boussinesq approximation are solved in curvilinear coordinates in a frame of reference moving the phase velocity of the wave. The shear driving the flow is created by an upper plane boundary moving horizontally with a bulk velocity in the x-direction. Periodic boundary conditions are considered in the horizontal (x) and lateral (y) directions, and no-slip boundary condition is considered in the vertical z-direction. The grid of nodes in the x, y, and z directions is used. The Adams-Bashforth method is employed to advance the integration in time and the equation for the pressure is solved iteratively by using FFT in the x and y directions and the Gauss method in the z-direction. Ensemble-averaged velocity and pressure fields are evaluated by averaging over time and the spanwise coordinate. Profiles of the mean velocity and turbulent stresses are obtained by

  10. Assessing microbiological water quality in drinking water distribution systems with disinfectant residual using flow cytometry.

    PubMed

    Gillespie, Simon; Lipphaus, Patrick; Green, James; Parsons, Simon; Weir, Paul; Juskowiak, Kes; Jefferson, Bruce; Jarvis, Peter; Nocker, Andreas

    2014-11-15

    Flow cytometry (FCM) as a diagnostic tool for enumeration and characterization of microorganisms is rapidly gaining popularity and is increasingly applied in the water industry. In this study we applied the method to obtain a better understanding of total and intact cell concentrations in three different drinking water distribution systems (one using chlorine and two using chloramines as secondary disinfectants). Chloramine tended to result in lower proportions of intact cells than chlorine over a wider residual range, in agreement with existing knowledge that chloramine suppresses regrowth more efficiently. For chlorinated systems, free chlorine concentrations above 0.5 mg L(-1) were found to be associated with relatively low proportions of intact cells, whereas lower disinfectant levels could result in substantially higher percentages of intact cells. The threshold for chlorinated systems is in good agreement with guidelines from the World Health Organization. The fact that the vast majority of samples failing the regulatory coliform standard also showed elevated proportions of intact cells suggests that this parameter might be useful for evaluating risk of failure. Another interesting parameter for judging the microbiological status of water, the biological regrowth potential, greatly varied among different finished waters providing potential help for investment decisions. For its measurement, a simple method was introduced that can easily be performed by water utilities with FCM capability. PMID:25123436

  11. Solute transport modelling in a coupled water and heat flow system applied to cold regions hydrogeology

    NASA Astrophysics Data System (ADS)

    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

  12. Velocity measurement and flow field simulation of a sit-type water closet

    NASA Astrophysics Data System (ADS)

    Cheng, Wei-Seng; Jhang, Chao-Yu

    2012-06-01

    Evacuation of a sit-type water closet is driven by siphon effect established inside its water passage when flushed. However, the flow condition in the passage of a water closet is still unclear. It is clear that we have a fundamental understanding of the flow phenomenon before we know how to enhance siphon effect. This research studies the flow phenomenon in the passage imbedded in a sit-type water closet by using both experimental measurement and numerical simulation. Particle-tracing technique by using a high speed camera is used to measure velocity of particles flowing with the water flow in a full scale model. These velocity values of particles are transformed to estimate the mean velocity of the water flow in the passage of the model throughout the time span of a flush. This velocity profile in time compares reasonably well in trend with literature data and is used to validate the results of subsequent numerical simulations. Numerical simulations of the transient flushed-flow based on in-compressible, viscous, turbulent and two-phase assumptions are performed. Simulation result agrees reasonably well with measurement data and can provide detail information of the transient flow field. Numerical simulation reveals that a clear circulation center exists in the flow and when siphon effect takes place water flow will reach its highest velocity value.

  13. Uncertainty of canal seepage losses estimated using flowing water balance with acoustic Doppler devices

    NASA Astrophysics Data System (ADS)

    Martin, Chad A.; Gates, Timothy K.

    2014-09-01

    Seepage losses from unlined irrigation canals amount to a large fraction of the total volume of water diverted for agricultural use, posing problems to both water conservation and water quality. Quantifying these losses and identifying areas where they are most prominent are crucial for determining the severity of seepage-related complications and for assessing the potential benefits of seepage reduction technologies and materials. A relatively easy and inexpensive way to estimate losses over an extensive segment of a canal is the flowing water balance, or inflow-outflow, method. Such estimates, however, have long been considered fraught with ambiguity due both to measurement error and to spatial and temporal variability. This paper presents a water balance analysis that evaluates uncertainty in 60 tests on two typical earthen irrigation canals. Monte Carlo simulation is used to account for a number of different sources of uncertainty. Issues of errors in acoustic Doppler flow measurement, in water level readings, and in evaporation estimates are considered. Storage change and canal wetted perimeter area, affected by variability in the canal prism, as well as lagged vs. simultaneous measurements of discharge at the inflow and outflow ends also are addressed. Mean estimated seepage loss rates for the tested canal reaches ranged from about -0.005 (gain) to 0.110 m3 s-1 per hectare of canal wetted perimeter (or -0.043 to 0.95 m d-1) with estimated probability distributions revealing substantial uncertainty. Across the tests, the average coefficient of variation was about 240% and the average 90th inter-percentile range was 0.143 m3 s-1 per hectare (1.24 m d-1). Sensitivity analysis indicates that while the predominant influence on seepage uncertainty is error in measured discharge at the upstream and downstream ends of the canal test reach, the magnitude and uncertainty of storage change due to unsteady flow also is a significant influence. Recommendations are

  14. Informing Hydrological Drought Response in Headwater Catchments Using Water Storage Estimated From GRACE: Storage-Flow Dynamics

    NASA Astrophysics Data System (ADS)

    Gaffney, R.; Tyler, S. W.; Harpold, A. A.; Volk, J. M.

    2015-12-01

    Quantifying the relationship between subsurface water storage and streamflow is challenging due to heterogeneity of surface-groundwater interactions in space and time. Hence, point measurements of storage from wells are insufficient to characterize the storage across a catchment, especially in mountainous environments with complex geology. Here, we present a novel approach to quantify the storage-flow relationship for catchments in the Sierra Nevada Mountains. For 23 gages in the Hydro-Climatic Data Network, the 7-day average annual minimum flow (drought flow) was computed for years 2003 to 2015. We then aggregated, for each gage, the associated storage time-series dataset from 1o gridded measurements of monthly Terrestrial Water Storage (TWS) derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Despite the significant mismatch between the spatial scales and temporal resolution, we found a strong empirical correlation between TWS and drought flow. From these relationships, we examined how physical characteristics of each catchment (such as size and geology) impact the observed nonlinear relationship between TWS and drought flow. Furthermore, we show how physical characteristics, such as geology/storage capacity, of catchments affect the sensitivity of decreasing flows to multi-year droughts. This research has the potential to help better quantify the streamflow-storage relationship in small mountainous catchments, as well as, classify catchments that may be more vulnerable to decreasing flows with multi-year droughts.

  15. Assessing factors affecting the thermal properties of a passive thermal refuge using three-dimensional hydrodynamic flow and transport modeling

    USGS Publications Warehouse

    Decker, Jeremy D.; Swain, Eric D.; Stith, Bradley M.; Langtimm, Catherine A.

    2013-01-01

    Everglades restoration activities may cause changes to temperature and salinity stratification at the Port of the Islands (POI) marina, which could affect its suitability as a cold weather refuge for manatees. To better understand how the Picayune Strand Restoration Project (PSRP) may alter this important resource in Collier County in southwestern Florida, the USGS has developed a three-dimensional hydrodynamic model for the marina and canal system at POI. Empirical data suggest that manatees aggregate at the site during winter because of thermal inversions that provide warmer water near the bottom that appears to only occur in the presence of salinity stratification. To study these phenomena, the environmental fluid dynamics code simulator was used to represent temperature and salinity transport within POI. Boundary inputs were generated using a larger two-dimensional model constructed with the flow and transport in a linked overland-aquifer density-dependent system simulator. Model results for a representative winter period match observed trends in salinity and temperature fluctuations and produce temperature inversions similar to observed values. Modified boundary conditions, representing proposed PSRP alterations, were also tested to examine the possible effect on the salinity stratification and temperature inversion within POI. Results show that during some periods, salinity stratification is reduced resulting in a subsequent reduction in temperature inversion compared with the existing conditions simulation. This may have an effect on POI’s suitability as a passive thermal refuge for manatees and other temperature-sensitive species. Additional testing was completed to determine the important physical relationships affecting POI’s suitability as a refuge.

  16. Water Collective Dynamics in Whole Photosynthetic Green Algae as Affected by Protein Single Mutation.

    PubMed

    Russo, Daniela; Rea, Giuseppina; Lambreva, Maya D; Haertlein, Michael; Moulin, Martine; De Francesco, Alessio; Campi, Gaetano

    2016-07-01

    In the context of the importance of water molecules for protein function/dynamics relationship, the role of water collective dynamics in Chlamydomonas green algae carrying both native and mutated photosynthetic proteins has been investigated by neutron Brillouin scattering spectroscopy. Results show that single point genetic mutation may notably affect collective density fluctuations in hydrating water providing important insight on the transmission of information possibly correlated to biological functionality. In particular, we highlight that the damping factor of the excitations is larger in the native compared to the mutant algae as a signature of a different plasticity and structure of the hydrogen bond network. PMID:27300078

  17. On the Flow of Atlantic Water Towards the Arctic Ocean; a Synergy Between Altimetry and Hydrography.

    NASA Astrophysics Data System (ADS)

    Chafik, L.; Nilsson, J.; Skagseth, O.; Lundberg, P.

    2015-12-01

    The Arctic climate is strongly influenced by the inflow of warm Atlantic water conveyed by the Norwegian Atlantic Slope Current (NwASC); the main heat conveyor into the Arctic Ocean. Based on sea surface height (SSH) data from altimetry, we develop a dynamical measure of the NwASC transport to diagnose its spatio-temporal variability. This supports a dynamical division of the NwASC into two flow regimes; the Svinøy Branch (SvB) in the Norwegian Sea, and the Fram Strait Branch (FSB) west of Spitsbergen. The SvB transport is well correlated with the SSH and atmospheric variability within the Nordic Seas, factors that also affect the inflow to the Barents Sea. In contrast, the FSB is regulated by regional atmospheric patterns around Svalbard and northern Barents Sea. We further relate anomalous flow events to temperature fluctuations of Atlantic water. A warm anomaly is found to propagate northwards, with a tendency to amplify enroute, after events of strong flow in the Norwegian Sea. A roughly 12-months delayed temperature signal is identified in the FSB. This suggests that hydrographic anomalies both upstream from the North Atlantic, and locally generated in the Norwegian Sea, are important for the oceanic heat and salt transport that eventually enters into the Arctic. We believe that the combination of the flow from altimetry and temperature fluctuations in the Nordic Seas can be used to qualitatively predict warm anomalies towards the Arctic Ocean, which could be a valuable addition to the forecast skill of the statistical Arctic sea-ice models.

  18. Nitrogen and water affect direct and indirect plant systemic induced defense in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested the affects of nitrogen levels and water availability on the ability of cotton plants to deter feeding by Spodoptera exigua larvae through induction of anti-feedant chemicals by the cotton plant, and to attract the biological control agent, Micropitis crociepes through induction of chemica...

  19. Water-triacylglycerol interactions affect oil body structure and seed viability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are investigating interactions between water and triacylglycerols (TAG) that appear to affect oil body stability and viability of seeds. Dried seeds are usually stored at freezer temperatures (-20oC) for long-term conservation of genetic resources. This globally accepted genebanking practice is...

  20. Volumetric flow rate comparisons for water and product on pasteurization systems.

    PubMed

    Schlesser, J E; Stroup, W H; McKinstry, J A

    1994-04-01

    A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system. PMID:8201053

  1. Water flow based geometric active deformable model for road network

    NASA Astrophysics Data System (ADS)

    Leninisha, Shanmugam; Vani, Kaliaperumal

    2015-04-01

    A width and color based geometric active deformable model is proposed for road network extraction from remote sensing images with minimal human interception. Orientation and width of road are computed from a single manual seed point, from which the propagation starts both right and left hand directions of the starting point, which extracts the interconnected road network from the aerial or high spatial resolution satellite image automatically. Here the propagation (like water flow in canal with defined boundary) is restricted with color and width of the road. Road extraction is done for linear, curvilinear (U shape and S shape) roads first, irrespective of width and color. Then, this algorithm is improved to extract road with junctions in a shape of L, T and X along with center line. Roads with small break or disconnected roads are also extracts by a modified version of this same algorithm. This methodology is tested and evaluated with various remote sensing images. The experimental results show that the proposed method is efficient and extracting roads accurately with less computation time. However, in complex urban areas, the identification accuracy declines due to the various sizes of obstacles, over bridges, multilane etc.

  2. Confocal Microscopy and Flow Cytometry System Performance: Assessment of QA Parameters that affect data Quanitification

    EPA Science Inventory

    Flow and image cytometers can provide useful quantitative fluorescence data. We have devised QA tests to be used on both a flow cytometer and a confocal microscope to assure that the data is accurate, reproducible and precise. Flow Cytometry: We have provided two simple perform...

  3. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  4. Ground-Water Flow Direction, Water Quality, Recharge Sources, and Age, Great Sand Dunes National Monument, South-Central Colorado, 2000-2001

    USGS Publications Warehouse

    Rupert, Michael G.; Plummer, L. Niel

    2004-01-01

    Great Sand Dunes National Monument is located in south-central Colorado along the eastern edge of the San Luis Valley. The Great Sand Dunes National Monument contains the tallest sand dunes in North America; some rise up to750 feet. Important ecological features of the Great Sand Dunes National Monument are palustrine wetlands associated with interdunal ponds and depressions along the western edge of the dune field. The existence and natural maintenance of the dune field and the interdunal ponds are dependent on maintaining ground-water levels at historic elevations. To address these concerns, the U.S. Geological Survey conducted a study, in collaboration with the National Park Service, of ground-water flow direction, water quality, recharge sources, and age at the Great Sand Dunes National Monument. A shallow unconfined aquifer and a deeper confined aquifer are the two principal aquifers at the Great Sand Dunes National Monument. Ground water in the unconfined aquifer is recharged from Medano and Sand Creeks near the Sangre de Cristo Mountain front, flows underneath the main dune field, and discharges to Big and Little Spring Creeks. The percentage of calcium in ground water in the unconfined aquifer decreases and the percentage of sodium increases because of ionic exchange with clay minerals as the ground water flows underneath the dune field. It takes more than 60 years for the ground water to flow from Medano and Sand Creeks to Big and Little Spring Creeks. During this time, ground water in the upper part of the unconfined aquifer is recharged by numerous precipitation events. Evaporation of precipitation during recharge prior to reaching the water table causes enrichment in deuterium (2H) and oxygen-18 (18O) relative to waters that are not evaporated. This recharge from precipitation events causes the apparent ages determined using chlorofluorocarbons and tritium to become younger, because relatively young precipitation water is mixing with older waters

  5. Effect of water supply method and flow rate on drinking behavior and fluid balance in horses.

    PubMed

    Nyman, S; Dahlborn, K

    2001-05-01

    This study investigated three methods of water supply on drinking preference and behavior in six Standardbred geldings (2-9 years, 505+/-9 kg). The water sources were buckets (B), pressure valve (PV), and float valve (FV) bowls. In an initial drinking preference test, PV was tested at three flow rates: 3, 8, and 16 l/min (PV3, PV8, and PV16), and FV at 3 l/min (FV3). Water intake was measured in l and presented as the percentage of the total daily water intake from each of two simultaneously presented alternatives. The intake from PV8 was greater than from both PV3 (72+/-11% vs. 28+/-11%) and PV16 (90+/-4% vs. 10+/-4%). All horses showed a strong preference for B, 98+/-1% of the intake compared to 2+/-1% from PV8. Individual variation in the data gave no significant difference in preference between the two automatic bowls. In the second part of the study, drinking behavior and fluid balance were investigated when the horses drank from FV3, PV8, and B for 7 consecutive days in a changeover design. Despite a tendency for an increase in total daily drinking time from FV3, the daily water intake was significantly lower (43+/-3 ml/kg) than from PV8 (54+/-2 ml/kg) and B (58+/-3 ml/kg). Daily net water gain [intake-(fecal+urinary output)] was only 0.5+/-3 ml/kg with FV3, resulting in a negative fluid balance if insensible losses are included. These results show that the water supply method can affect both drinking behavior and fluid balance in the horse. PMID:11399288

  6. Flow structures in submarine channels affected by Coriolis forces: Experimental observations

    NASA Astrophysics Data System (ADS)

    Cossu, R.; Wells, M. G.

    2011-12-01

    In this talk we will show how Coriolis forces can control the flow dynamics of turbidity currents flowing in sinuous channels at high latitudes. We describe how the internal velocity structure changes with latitude, based on observations from rotating laboratory experiments. When these results are combined with existing conceptual facies and depositional models we can now describe the changes in sedimentation patterns that are observed at different latitudes. The experiments were conducted in a sinuous channel model placed in a tank that was rotated at various rates (reflected by the Coriolis parameters f) ranging from f = 0 (at the equator) to ± 0.5 rad s-1 (at higher latitudes). The dependence of the density interface of gravity currents on rotation is shown in Figure 1a. At the equator the interface slopes up to the outer bend due to the centrifugal forces. In the Northern Hemisphere (NH) the tilt of the interface increases as now the Coriolis forces reinforce the centrifugal acceleration. In contrast, in the Southern Hemisphere (SH) the current ramps up to the inner bend and Coriolis forces dominate over centrifugal forces. Figure 1b shows the corresponding position of the downstream velocity core in the bend apex. At the equator the core is predominantly close to the centerline, whilst in the NH the core is deflected to the inner bend and in the SH the velocity core is shifted to the outer bank. Based upon our experimental results, we hypothesize that Coriolis forces can affect the velocity structure and sedimentation regime. Lateral accretion packages (LAPs) are built only on one side in the channel and finer sediments will be deposited mainly on the levee bank to which the high velocity core is deflected. The Rossby number RoW = U/fW (where U is the mean downstream velocity and W the channel width) can be used to determine the influence of Coriolis forces. In channel systems at high-latitudes (with RoW << 1) we predict that channels exhibit a low sinuosity

  7. Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

    NASA Astrophysics Data System (ADS)

    Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

    2006-12-01

    The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or

  8. Drinking Water Sodium and Elevated Blood Pressure of Healthy Pregnant Women in Salinity-Affected Coastal Areas.

    PubMed

    Scheelbeek, Pauline F D; Khan, Aneire E; Mojumder, Sontosh; Elliott, Paul; Vineis, Paolo

    2016-08-01

    Coastal areas in Southeast Asia are experiencing high sodium concentrations in drinking water sources that are commonly consumed by local populations. Salinity problems caused by episodic cyclones and subsequent seawater inundations are likely (partly) related to climate change and further exacerbated by changes in upstream river flow and local land-use activities. Dietary (food) sodium plays an important role in the global burden of hypertensive disease. It remains unknown, however, if sodium in drinking water-rather than food-has similar effects on blood pressure and disease risk. In this study, we examined the effect of drinking water sodium on blood pressure of pregnant women: increases in blood pressure in this group could severely affect maternal and fetal health. Data on blood pressure, drinking water source, and personal, lifestyle, and environmental confounders was obtained from 701 normotensive pregnant women residing in coastal Bangladesh. Generalized linear mixed regression models were used to investigate association of systolic and diastolic blood pressure of these-otherwise healthy-women with their water source. After adjustment for confounders, drinkers of tube well and pond water (high saline sources) were found to have significantly higher average systolic (+4.85 and +3.62 mm Hg) and diastolic (+2.30 and +1.72 mm Hg) blood pressures than rainwater drinkers. Drinking water salinity problems are expected to exacerbate in the future, putting millions of coastal people-including pregnant women-at increased risk of hypertension and associated diseases. There is an urgent need to further explore the health risks associated to this understudied environmental health problem and feasibility of possible adaptation strategies. PMID:27297000

  9. Reconnaissance Study of Water Quality in the Mining-Affected Aries River Basin, Romania

    USGS Publications Warehouse

    Friedel, Michael J.; Tindall, James A.; Sardan, Daniel; Fey, David L.; Poputa, G.L.

    2008-01-01

    The Aries River basin of western Romania has been subject to mining activities as far back as Roman times. Present mining activities are associated with the extraction and processing of various metals including Au, Cu, Pb, and Zn. To understand the effects of these mining activities on the environment, this study focused on three objectives: (1) establish a baseline set of physical parameters, and water- and sediment-associated concentrations of metals in river-valley floors and floodplains; (2) establish a baseline set of physical and chemical measurements of pore water and sediment in tailings; and (3) provide training in sediment and water sampling to personnel in the National Agency for Mineral Resources and the Rosia Poieni Mine. This report summarizes basin findings of physical parameters and chemistry (sediment and water), and ancillary data collected during the low-flow synoptic sampling of May 2006.

  10. The soil-water flow system beneath a cotton field in arid north-west China, serviced by mulched drip irrigation using brackish water

    NASA Astrophysics Data System (ADS)

    Li, Xianwen; Jin, Menggui; Huang, Jinou; Yuan, Jingjing

    2015-02-01

    A field experiment was carried out in southern Xinjiang, China, to reveal soil-water flow pattern beneath a combined plastic-mulch (film) and drip-irrigation system using brackish water. The soil-water flow system (SWFS) was characterized from soil surface to the water table based on observed spatio-temporal distribution of total soil-water potential, water content and electric conductivity. Root suction provided a strong inner sink. The results indicated that SWFS determined the soil salinity and moisture distribution. Drip-irrigation events could leach excess salts from the root zone and provide soil conditions with a tolerable salinity level that supports the growth of cotton. High-salinity strips were formed along the wetting front and at the bare soil surface. Hydrogeology conditions, irrigation regime, climate, plant growth and use of mulch would affect potential sources and sinks, boundary conditions and the size of the SWFS. At depth 0-60 cm, the soil salinity at the end of the irrigation season was 1.9 times that at the beginning. Beneath the mulch cover, the soil-water content in the `wide rows' zone (55 cm between the two rows with no drip line) was higher than that in the `narrow rows' zone (15 cm between the two rows with a drip line) due to the strong root-water uptake. The downward water flow below the divergent curved surface of zero flux before irrigation, and the water-table fluctuation with irrigation events, indicated that excessive irrigation occurred.

  11. Recent trends in nitrogen flows with urbanization in the Shanghai megacity and the effects on the water environment.

    PubMed

    Liu, Chen; Wang, Qinxue; Zou, Chunjing; Hayashi, Yoshitsugu; Yasunari, Tetsuzo

    2015-03-01

    The objectives of this study are to diagnose and prevent environmental problems that threaten urban sustainability, the impact of changes in lifestyle (diet, domestic sanitation, and motorization), and production style (agriculture, industry, and services) with the rapid urbanization on regional nitrogen (N) flows, and the water environment was quantitatively evaluated. The megacity Shanghai was chosen as a case study to investigate the temporal changes in nitrogen flow during 1980-2008 by a multidisciplinary approach (a field survey, a regional nitrogen mass balance model, input-output analysis, etc.). Although the total potential nitrogen load in Shanghai has decreased in the 2000s and water pollution problems seem to have improved, the problem has shifted and expanded to affect a wider area through the food/product chain and water/air movement. Further effective solutions that aim at material cycles are necessary and have to be implemented on a large scale. PMID:25422114

  12. Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.

    PubMed

    Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R

    2014-09-15

    Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads. PMID:25016109

  13. Principles of Water Flow in Real-World Soils and Related Imbalances

    NASA Astrophysics Data System (ADS)

    Lin, H.

    2012-12-01

    Heterogeneities, structures, interfaces, roughness, and organisms in multiphase soil systems make the real-world soil deviated significantly from the continuum assumption. The first principle of water flow in porous media came to light in the 19th century, known as the Darcy's law, which was later modified by E. Buckingham to describe unsaturated water flow in soils. This principle is essentially a macroscopic view of steady-state water flux being linearly proportional to hydraulic gradient and hydraulic conductivity. The second principle was proposed by L.A. Richards in the 20th century, which describes the minimum pressure gradient needed to initiate water flow through the soil-air interface. This principle can be extended to provide a more cohesive explanation to a number of soil hydrologic phenomena related to various interfaces and microscopic features (such as hysteresis, hydrophobicity, and flow through layered soils). The third principle is emerging in the 21st century, where a combined macroscopic and microscopic view portrays mosaic-like complex flow regimes in heterogeneous soils in which imbalance seems to be common leading to widespread preferential flow. The dynamic interaction between preferential flow and matrix flow under changing conditions results in complex, evolving flow networks that are embedded in the matrix of land surface and subsurface. Quantification and integration of these flow principles can lead to improved prediction of water flow in real-world soils and landscapes.

  14. Time-dependent response of a charcoal bed to radon and water vapor in flowing air

    SciTech Connect

    Henkel, J.A.; Fentiman, A.W.; Blue, T.E.

    1995-12-31

    Extremely high airborne concentrations of radon gas may be encountered during the remediation of uranium mill tailings storage facilities. Radon is also a constituent of the off-gas of mill-tailing vitrification. An effective way to remove radon from either gas is to pass the gas through a packed bed containing activated charcoal. Measurements of radon concentrations in the environment using charcoal canisters were first described by George. Canisters similar to those used by George in his first experiments have become the U.S. Environmental Protection Agency`s (EPA`s) standard for measuring environmental radon and were described in the EPA protocol for environmental radon measurement. The dynamic behavior of EPA charcoal canisters has been previously described with a mathematical model for the kinetics of radon gas adsorption in air in the presence of water vapor. This model for charcoal canisters has been extended to large charcoal beds with flowing air containing radon and water vapor. The mathematical model for large charcoal beds can be used to evaluate proposed bed designs or to model existing beds. Parameters that affect the radon distribution within a charcoal bed that can be studied using the mathematical model include carrier gas relative humidity and flow velocity, and input radon concentration. In addition, the relative performances of several different charcoals can be studied, provided sufficient information about their adsorption, desorption, and diffusion constants is known.

  15. Flow injection method for the determination of silver concentration in drinking water for spacecrafts.

    PubMed

    Bruzzoniti, Maria Concetta; Kobylinska, Dorota Korte; Franko, Mladen; Sarzanini, Corrado

    2010-04-14

    A flow injection method has been developed for determination of silver. The method is based on a reduction reaction with sodium borohydride which leads to the formation of a colloidal species which is monitored at a wavelength of 390 nm. The reaction variables flow rate, sodium borohydride concentration and pH, which affect sensitivity, were investigated and their effects were established using a two-levels, three-factor experimental design. Further optimization of manifold variables (reaction coil and injection volume) allowed us to determine silver in the range 0.050-5.0 mg L(-1) with a minimum detectable concentration of 0.050 mg L(-1). Silver is added, as biocide, to drinking water for spacecrafts. The chemical species of silver, present in this kind of sample, were characterized by a procedure based on the selective retention of Ag(+) onto a 2.2.2. cryptand based substrate followed by determination of the non-bound and bound (after elution) Ag(+) by the FIA method. The method optimized was applied to a drinking water sample provided for the launch with the Automated Transfer Vehicle (ATV) module Jule Verne to the International Space Station (March 9, 2008). PMID:20381692

  16. Applying velocity profiling technology to flow measurement at the Orinda water treatment plant

    SciTech Connect

    Metcalf, M.A.; Kachur, S.; Lackenbauer, S.

    1998-07-01

    A new type of flow measurement technology, velocity profiling, was tested in the South Channel of the Orinda Water Treatment Plant. This new technology allowed installation in the difficult hydraulic conditions of the South Channel, without interrupting plant operation. The advanced technology of velocity profiling enables flow measurements to be obtained in sites normally unusable by more traditional methods of flow rate measurement.

  17. ENVIRONMENTAL RESEARCH BRIEF : ANALYTIC ELEMENT MODELING OF GROUND-WATER FLOW AND HIGH PERFORMANCE COMPUTING

    EPA Science Inventory

    Several advances in the analytic element method have been made to enhance its performance and facilitate three-dimensional ground-water flow modeling in a regional aquifer setting. First, a new public domain modular code (ModAEM) has been developed for modeling ground-water flow ...

  18. A Device to Emulate Diffusion and Thermal Conductivity Using Water Flow

    ERIC Educational Resources Information Center

    Blanck, Harvey F.

    2005-01-01

    A device designed to emulate diffusion and thermal conductivity using flowing water is reviewed. Water flowing through a series of cells connected by a small tube in each partition in this plastic model is capable of emulating diffusion and thermal conductivity that occurs in variety of systems described by several mathematical equations.

  19. Water Resources management and environmental flows under physicochemical and ecological considerations.

    NASA Astrophysics Data System (ADS)

    Paredes-Arquiola, Javier; Solera-Solera, Abel; Martínez-Capel, Francisco; Momblanch-Benavent, Andrea; Andreu-Álvarez, Joaquín

    2013-04-01

    Multidisciplinary models are useful for integrating different disciplines when addressing water planning and management problems. Coupling tools of water resources management, water quality and habitat analysis is important to propose water allocation solutions in different environmental flows scenarios. The Decision Support System AQUATOOL allows the construction of the three kinds of models: the SIMGES model solves the allocation problem through network flow optimisation and considers the environmental flows in selected river stretches; the GESCAL model performs the water quality in rivers and reservoirs; and the CAUDECO model assesses habitat suitability, providing Habitat Time Series for each available WUA-flow curve. Furthermore, the general methodological framework is improved by implementing a hydrological alteration assessment of the e-flow regime scenarios. This approach was applied in the Tormes River Water Resources System, where agricultural demands endanger the environmental needs of the river ecosystem. Moreover, the wastewater loading and the agricultural pollution result in water quality problems in some river stretches. Our methodological framework can be used to define water management rules that maintain water supply, aquatic ecosystem and water quality legal standards. The integration of ecological and water management criteria in a software platform allows the optimization and application of environmental flows, considering the real constrains in the legal and economical framework of a river basin.

  20. Analysis of internal flow characteristics of a smooth-disk water-brake dynamometer

    NASA Technical Reports Server (NTRS)

    Evans, D. G.

    1973-01-01

    The principal of absorbing power with an enclosed partially submerged rotating disk through the turbulent viscous shearing of water is discussed. Reference information is used to develop a flow model of the water brake. A method is then presented that uses vector diagrams to relate the effects of rotational flow, through flow, and secondary flow to power absorption. The method is used to describe the operating characteristics of an example 111-cm (43.7-in.) diameter water brake. Correlating performance parameters are developed in a dimensional analysis.

  1. Impacts of Lithological and Anthropogenic Factors Affecting Water Chemistry in the Upper Paraguay River Basin.

    PubMed

    Rezende-Filho, Ary T; Valles, Vincent; Furian, Sônia; Oliveira, Célia M S C; Ouardi, Jamila; Barbiero, Laurent

    2015-11-01

    Located in the Upper Paraguay River Basin (UPRB), the Pantanal is considered the world's largest wetland, being rather pristine although increasingly threatened by development programs. The main objective of this paper is to provide a baseline of water chemistry for this region, which is largely unknown as a result of poor accessibility. We used two datasets (70 and 122 water samples) collected in the Pantanal floodplain and surrounding uplands during the wet season occurring from November to March. From the major-ion mineral chemistry, dissolved silica, pH, electrical conductivity (EC), and the ionic forms of N, principal components analysis (PCA) treatments were used to identify and rank the main factors of variability and decipher the associated processes affecting the water chemistry. The results revealed that the water mineral concentration was a major factor of variability and it must be attributed first to lithology and second to agricultural inputs from extensive crop cultivation areas that mainly affects sulfate (SO) concentration on the eastern edge of the Pantanal. These processes influence the floodplain, where (i) the mixing of waters remains the main process, (ii) the weight of the biological and redox processes increased, and (iii) the chemical signature of the extensive cropping is transferred along the São Lourenço Basin down to its confluence with the Cuiaba River. Optimized parameters based on projections in the main factorial score plots were used for the mapping of lithological and agricultural impacts on water chemistry. PMID:26641335

  2. Ground-water flow patterns and water budget of a bottomland forested wetland, Black Swamp, eastern Arkansas

    USGS Publications Warehouse

    Gonthier, G.J.; Kleiss, B.A.

    1996-01-01

    The U.S. Geological Survey, working in cooperation with the U.S. Army Corps of Engineers, Waterways Experiment Station, collected surface-water and ground-water data from 119 wells and 13 staff gages from September 1989 to September 1992 to describe ground-water flow patterns and water budget in the Black Swamp, a bottomland forested wetland in eastern Arkansas. The study area was between two streamflow gaging stations located about 30.5 river miles apart on the Cache River. Ground-water flow was from northwest to southeast with some diversion toward the Cache River. Hydraulic connection between the surface water and the alluvial aquifer is indicated by nearly equal changes in surface-water and ground-water levels near the Cache River. Diurnal fluctuations of hydraulic head ranged from more than 0 to 0.38 feet and were caused by evapotranspiration. Changes in hydraulic head of the alluvial aquifer beneath the wetland lagged behind stage fluctuations and created the potential for changes in ground-water movement. Differences between surface-water levels in the wetland and stage of the Cache River created a frequently occurring local ground-water flow condition in which surface water in the wetland seeped into the upper part of the alluvial aquifer and then seeped into the Cache River. When the Cache River flooded the wetland, ground water consistently seeped to the surface during falling surface-water stage and surface water seeped into the ground during rising surface-water stage. Ground-water flow was a minor component of the water budget, accounting for less than 1 percent of both inflow and outflow. Surface-water drainage from the study area through diversion canals was not accounted for in the water budget and may be the reason for a surplus of water in the budget. Even though ground-water flow volume is small compared to other water budget components, ground-water seepage to the wetland surface may still be vital to some wetland functions.

  3. Estimating water flow through a hillslope using the massively parallel processor

    NASA Technical Reports Server (NTRS)

    Devaney, Judy E.; Camillo, P. J.; Gurney, R. J.

    1988-01-01

    A new two-dimensional model of water flow in a hillslope has been implemented on the Massively Parallel Processor at the Goddard Space Flight Center. Flow in the soil both in the saturated and unsaturated zones, evaporation and overland flow are all modelled, and the rainfall rates are allowed to vary spatially. Previous models of this type had always been very limited computationally. This model takes less than a minute to model all the components of the hillslope water flow for a day. The model can now be used in sensitivity studies to specify which measurements should be taken and how accurate they should be to describe such flows for environmental studies.

  4. Do Amplitudes of Water Level Fluctuations Affect the Growth and Community Structure of Submerged Macrophytes?

    PubMed Central

    Wang, Mo-Zhu; Liu, Zheng-Yuan; Luo, Fang-Li; Lei, Guang-Chun; Li, Hong-Li

    2016-01-01

    Submerged macrophytes are subjected to potential mechanical stresses associated with fluctuating water levels in natural conditions. However, few experimental studies have been conducted to further understand the effects of water level fluctuating amplitude on submerged macrophyte species and their assemblages or communities. We designed a controlled experiment to investigate the responses of three submerged macrophyte species (Hydrilla verticillata, Ceratophyllum demersum and Elodea nuttallii) and their combinations in communities to three amplitudes (static, ± 30 cm, ± 60 cm) of water level fluctuations. Results showed that water level fluctuating amplitude had little effects on the community performance and the three tested species responded differently. H. verticillata exhibited more growth in static water and it was negatively affected by either of the water level fluctuations amplitude, however, growth parameters of H. verticillata in two fluctuating water level treatments (i.e., ± 30 cm, ± 60 cm) were not significantly different. On the other hand, the growth of C. demersum was not significantly correlated with different amplitude treatments. However, it became more abundant when water levels fluctuated. E. nuttallii was inhibited by the two fluctuating water level treatments, and was less in growth parameters compared to the other species especially in water level fluctuating conditions. The inherent differences in the adaptive capabilities of the tested species indicate that C. demersum or other species with similar responses may be dominant species to restore submerged macrophyte communities with great fluctuating water levels. Otherwise, H. verticillata, E. nuttallii or other species with similar responses could be considered for constructing the community in static water conditions. PMID:26735689

  5. Low-flow water-quality characterization of the Gore Creek watershed, upper Colorado River basin, Colorado, August 1996

    USGS Publications Warehouse

    Wynn, Kirby H.; Spahr, Norman E.

    1998-01-01

    The Upper Colorado River Basin (UCOL) is one of 59 National Water-Quality Assessment (NAWQA) study units designed to assess the status and trends of the Nation?s water quality (Leahy and others, 1990). The UCOL study unit began operation in 1994, and surface-water-quality data collection at a network of 14 sites began in October 1995 (Apodaca and others, 1996; Spahr and others, 1996). Gore Creek, which flows through Vail, Colorado, originates in pristine alpine headwaters and is designated a gold-medal trout fishery. The creek drains an area of about 102 square miles and is a tributary to the Eagle River. Gore Creek at the mouth near Minturn (site 13 in fig. 1) is one of the 14 sites in the UCOL network. This site was selected to evaluate water quality resulting from urban development and recreational land use. The Gore Creek watershed has undergone rapid land-use changes since the 1960?s as the Vail area shifted from traditional mountain ranchlands to a four-season resort community. Residential, recreational, commercial, and transportation development continues near Gore Creek and its tributaries to support the increasing permanent and tourist population of the area. Interstate 70 runs through the watershed from Vail Pass near site 14, along the eastern side of Black Gore Creek, and along the northern side of the main stem of Gore Creek to the mouth of the watershed (fig. 1). A major local concern is how increasing urbanization/recreation affects the water quality, gold-medal trout fishery, and aesthetic values of Gore Creek. An evaluation of the spatial characteristics of water quality in the watershed upstream from site 13 at the mouth of Gore Creek (fig. 1) can provide local water and land managers with information necessary to establish water policy and make land-use planning decisions to maintain or improve water quality. Historical data collected at the mouth of Gore Creek provide information about water quality resulting from land use, but a synoptic

  6. A Lattice Boltzmann model for simulating water flow at pore scale in unsaturated soils

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoxian; Crawford, John W.; Young, Iain M.

    2016-07-01

    The Lattice Boltzmann (LB) method is an established prominent model for simulating water flow at pore scale in saturated porous media. However, its application in unsaturated soil is less satisfactory because of the difficulties associated with most two-phase LB models in simulating immiscible fluids, such as water and air, which have contrasting densities and viscosities. While progress has been made in developing LB models for fluids with high density ratio, they are still prone to numerical instability and cannot accurately describe the interfacial friction on water-air interface in unsaturated media. Considering that one important application of the LB model in porous materials is to calculate their hydraulic properties when flow is at steady state, we develop a simple LB model to simulate steady water flow at pore scale in unsaturated soils. The method consists of two steps. The first one is to determine water distribution within the soil structure using a morphological model; once the water distribution is known, its interfaces with air are fixed. The second step is to use a single-phase LB model to simulate water flow by treating the water-air interfaces as free-flow boundaries where the shear resistance of air to water flow is assumed to be negligible. We propose a method to solve such free-flow boundaries, and validate the model against analytical solutions of flows of water film over non-slip walls in both two and three dimensions. We then apply the model to calculate water retention and hydraulic properties of a medium acquired using X-ray computed tomography at resolution of 6 μm. The model is quasi-static, similar to the porous network model, but is an improvement as it directly simulates water flow in the pore geometries acquired by tomography without making any further simplifications.

  7. A water balance model to estimate flow through the Old and Middle River corridor

    USGS Publications Warehouse

    Andrews, Stephen W.; Gross, Edward S.; Hutton, Paul H.

    2016-01-01

    We applied a water balance model to predict tidally averaged (subtidal) flows through the Old River and Middle River corridor in the Sacramento–San Joaquin Delta. We reviewed the dynamics that govern subtidal flows and water levels and adopted a simplified representation. In this water balance approach, we estimated ungaged flows as linear functions of known (or specified) flows. We assumed that subtidal storage within the control volume varies because of fortnightly variation in subtidal water level, Delta inflow, and barometric pressure. The water balance model effectively predicts subtidal flows and approaches the accuracy of a 1–D Delta hydrodynamic model. We explore the potential to improve the approach by representing more complex dynamics and identify possible future improvements.

  8. Numerical and experimental study on the flow distribution in a water manifold

    NASA Astrophysics Data System (ADS)

    Min, Gwansik; Jong Lee, Pil; Kang, Jong Hoon

    2016-03-01

    This study presents water distribution analysis of the device for spraying cooling water through specific nozzles numerically and experimentally. Numerical analysis was performed using the 3-D incompressible, multi-phase flow model, for different Reynolds numbers of 4 × 105, 8 × 105. Experimental analysis was performed at real-size, under the same conditions. The calculated results and the measured results for the distribution of flow were matched relatively well. The distribution of the nozzle flow depends on the Reynolds number.

  9. Regularized shallow water equations for numerical simulation of flows with a moving shoreline

    NASA Astrophysics Data System (ADS)

    Bulatov, O. V.; Elizarova, T. G.

    2016-04-01

    A numerical algorithm for simulating free-surface flows based on regularized shallow water equations is adapted to flows involving moving dry-bed areas. Well-balanced versions of the algorithm are constructed. Test computations of flows with dry-bed areas in the cases of water runup onto a plane beach and a constant-slope beach are presented. An example of tsunami simulation is given.

  10. Development of a stream-aquifer numerical flow model to assess river water management under water scarcity in a Mediterranean basin.

    PubMed

    Mas-Pla, Josep; Font, Eva; Astui, Oihane; Menció, Anna; Rodríguez-Florit, Agustí; Folch, Albert; Brusi, David; Pérez-Paricio, Alfredo

    2012-12-01

    Stream flow, as a part of a basin hydrological cycle, will be sensible to water scarcity as a result of climate change. Stream vulnerability should then be evaluated as a key component of the basin water budget. Numerical flow modeling has been applied to an alluvial formation in a small mountain basin to evaluate the stream-aquifer relationship under these future scenarios. The Arbúcies River basin (116 km(2)) is located in the Catalan Inner Basins (NE Spain) and its lower reach, which is related to an alluvial aquifer, usually becomes dry during the summer period. This study seeks to determine the origin of such discharge losses whether from natural stream leakage and/or induced capture due to groundwater withdrawal. Our goal is also investigating how discharge variations from the basin headwaters, representing potential effects of climate change, may affect stream flow, aquifer recharge, and finally environmental preservation and human supply. A numerical flow model of the alluvial aquifer, based on MODFLOW and especially in the STREAM routine, reproduced the flow system after the usual calibration. Results indicate that, in the average, stream flow provides more than 50% of the water inputs to the alluvial aquifer, being responsible for the amount of stored water resources and for satisfying groundwater exploitation for human needs. Detailed simulations using daily time-steps permit setting threshold values for the stream flow entering at the beginning of the studied area so surface discharge is maintained along the whole watercourse and ecological flow requirements are satisfied as well. The effects of predicted rainfall and temperature variations on the Arbúcies River alluvial aquifer water balance are also discussed from the outcomes of the simulations. Finally, model results indicate the relevance of headwater discharge management under future climate scenarios to preserve downstream hydrological processes. They also point out that small mountain basins

  11. Experimental and numerical modelling of surface water-groundwater flow and pollution interactions under tidal forcing

    NASA Astrophysics Data System (ADS)

    Spanoudaki, Katerina; Bockelmann-Evans, Bettina; Schaefer, Florian; Kampanis, Nikolaos; Nanou-Giannarou, Aikaterini; Stamou, Anastasios; Falconer, Roger

    2015-04-01

    Surface water and groundwater are integral components of the hydrologic continuum and the interaction between them affects both their quantity and quality. However, surface water and groundwater are often considered as two separate systems and are analysed independently. This separation is partly due to the different time scales, which apply in surface water and groundwater flows and partly due to the difficulties in measuring and modelling their interactions (Winter et al., 1998). Coastal areas in particular are a difficult hydrologic environment to represent with a mathematical model due to the large number of contributing hydrologic processes. Accurate prediction of interactions between coastal waters, groundwater and neighbouring wetlands, for example, requires the use of integrated surface water-groundwater models. In the past few decades a large number of mathematical models and field methods have been developed in order to quantify the interaction between groundwater and hydraulically connected surface water bodies. Field studies may provide the best data (Hughes, 1995) but are usually expensive and involve too many parameters. In addition, the interpretation of field measurements and linking with modelling tools often proves to be difficult. In contrast, experimental studies are less expensive and provide controlled data. However, experimental studies of surface water-groundwater interaction are less frequently encountered in the literature than filed studies (e.g. Ebrahimi et al., 2007; Kuan et al., 2012; Sparks et al., 2013). To this end, an experimental model has been constructed at the Hyder Hydraulics Laboratory at Cardiff University to enable measurements to be made of groundwater transport through a sand embankment between a tidal water body such as an estuary and a non-tidal water body such as a wetland. The transport behaviour of a conservative tracer was studied for a constant water level on the wetland side of the embankment, while running a

  12. Ohm's Law, Fick's Law, Joule's Law, and Ground Water Flow

    SciTech Connect

    Narasimhan, T.N.

    1999-02-01

    Starting from the contributions of Ohm, Fick and Joule during the nineteenth century, an integral expression is derived for a steady-state groundwater flow system. In general, this integral statement gives expression to the fact that the steady-state groundwater system is characterized by two dependent variables, namely, flow geometry and fluid potential. As a consequence, solving the steady-state flow problem implies the finding of optimal conditions under which flow geometry and the distribution of potentials are compatible with each other, subject to the constraint of least action. With the availability of the digital computer and powerful graphics software, this perspective opens up possibilities of understanding the groundwater flow process without resorting to the traditional differential equation. Conceptual difficulties arise in extending the integral expression to a transient groundwater flow system. These difficulties suggest that the foundations of groundwater hydraulics deserve to be reexamined.

  13. Experimental on two sensors combination used in horizontal pipe gas-water two-phase flow

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Dong, Feng

    2014-04-01

    Gas-water two phase flow phenomenon widely exists in production and living and the measurement of it is meaningful. A new type of long-waist cone flow sensor has been designed to measure two-phase mass flow rate. Six rings structure of conductance probe is used to measure volume fraction and axial velocity. The calibration of them have been made. Two sensors have been combined in horizontal pipeline experiment to measure two-phase flow mass flow rate. Several model of gas-water two-phase flow has been discussed. The calculation errors of total mass flow rate measurement is less than 5% based on the revised homogeneous flow model.

  14. Experimental on two sensors combination used in horizontal pipe gas-water two-phase flow

    SciTech Connect

    Wu, Hao; Dong, Feng

    2014-04-11

    Gas-water two phase flow phenomenon widely exists in production and living and the measurement of it is meaningful. A new type of long-waist cone flow sensor has been designed to measure two-phase mass flow rate. Six rings structure of conductance probe is used to measure volume fraction and axial velocity. The calibration of them have been made. Two sensors have been combined in horizontal pipeline experiment to measure two-phase flow mass flow rate. Several model of gas-water two-phase flow has been discussed. The calculation errors of total mass flow rate measurement is less than 5% based on the revised homogeneous flow model.

  15. Comparison of CFD simulations and measurements of flow affected by coanda effect

    NASA Astrophysics Data System (ADS)

    Fišer, Jan; Jedelský, Jan; Vach, Tomáš; Forman, Matěj; Jícha, Miroslav

    2012-04-01

    The article deals with experimental research and numerical simulations of specific phenomena in fluid flows called Coanda effect (CE), which has numerous important engineering applications. Although many researchers have concerned with wall jets, the physics of this flow still remains not well understood. This study is focused on analysis of behaviour of jet flow close to the wall and influence of its inclination. The flow has been visualized using smoke and velocity was measured by means of Hot Wire Anemometry (HWA). CFD simulations have been performed on the same geometry and compared with experiments in order to find a tool for correct prediction of the CE.

  16. Effect of metals on water flow in glutaraldehyde fixed toad bladder

    SciTech Connect

    Hoch, B.S.; Gorfien, P.C.; Eres, A.; Shahmehdi, S.; Lipner, H.I. )

    1990-02-26

    The authors previously reported that HgCl{sub 2} inhibits flow in tissues fixed with glutaraldehyde after ADH stimulation. The authors examined the effect of numerous other metals on the ADH-induced water channel. Water flows were measured gravimetrically. In glutaraldehyde-fixed tissues water flow and sucrose permeability are maintained from pH 2.5 through pH 12. Several metals including Ba, Co, Fe, La, Sr, and Zn have no effect on flow. Al, Cd, Cu, Pb, and U all elicit a small but significant increase in water flow associated with inhibition of the increased sucrose permeability normally observed in glutaraldehyde-fixed tissues. Ag inhibits flow but increases sucrose permeability. Au inhibits flow by 90% in tissues fixed after pretreatment with ADH but increases the permeability of tissues fixed in the absence of ADH. These effects may result from disruption of epithelial integrity rather than direct blocking of the ADH-induced water channel. At pH {le} 3, Pt inhibits flow in ADH-pretreated tissues. Sucrose permeability is decreased and basal flow unaffected. No inhibitory effect is present at pH {ge} 3.5. The data indicate that at physiologic pH, the ADH induced water channel is blocked specifically by Hg but not by other metals.

  17. Flow structure of water in carbon nanotubes: Poiseuille type or plug-like?

    NASA Astrophysics Data System (ADS)

    Hanasaki, Itsuo; Nakatani, Akihiro

    2006-04-01

    We have conducted molecular dynamics simulations of water flow in carbon nanotubes (CNTs) for (6,6) to (20,20) CNTs at a streaming velocity of 100m/s. The fluidized piston model (FPM) and the ice piston model (IPM) are employed to drive flow through the CNTs. The results show that the single-file water flow inside (6,6) CNT has a convex upward streaming velocity profile, whereas the velocity profiles in (10,10) to (20,20) CNTs are flat except near the tube wall. The flow structure of cylindrical water in the (8,8) CNT is intermediate between that for the (6,6) CNT and the larger CNTs. The flow parameters are found not to exhibit any dependence on streaming velocity at up to 300m/s in the (12,12) CNT. The hydrogen bond lifetimes of water flowing in CNTs tend to be longer than for the corresponding equilibrium states, and nonzero flow does not reduce the microscopic structure or structural robustness (hydrogen bond lifetime). Although the atomic density profile varies with tube diameter, reflecting the change in static microscopic structure of flow from single file to cylindrical, tube diameter does not induce a clear transition in streaming velocity, temperature, or hydrogen bond lifetime over this diameter range. The results suggest that water flow in CNTs of this size is more pluglike than Poiseuille type, although the flow structure does not strictly accord with either definition.

  18. Water Imbibition into Rock as Affected by Sample Shape, Pore, Conductivity, and Antecedent Water Content

    SciTech Connect

    R.P. Ewing

    2005-08-29

    Infiltration is often presumed to follow Philip's equation, I = st{sup 1/2}, where I is cumulative infiltration, s is sorptivity, and t is time. This form of the equation is appropriate for short times, and/or for negligible gravitational effects. For a uniform soil, this equation describes a plot of log(mass imbibed) versus log(time), with a slope (imbibition exponent) of 1/2. The equation has also been applied to low-porosity rocks, where the extremely small pores render gravitational forces negligible. Experiments recently performed on a wide variety of rocks produced imbibition exponents from 0.2 to 0.5. Many rock types showed initial imbibition proceeding as I {approx} t{sup 1/4}, then later switched to ''normal'' (t{sup 1/2}) behavior. The distance to the wetting front that corresponds to this cross-over behavior was found to be related to the sample shape: tall thin samples are more likely to exhibit the exponent 1/4, and to cross over to 1/2-type behavior later, while short, squat samples are less likely to display the 1/4-type behavior at all. Additionally, the exponents are sensitive to antecedent water content, with initially wetter samples having smaller values. In this study, we present the experimental data, and provide a consistent and physically-based explanation using percolation theory. The analogy between imbibition and diffusion is used to model imbibition into samples with low pore connectivity, with the exponents and their crossover behavior emerging from a random walk process. All laboratory phenomena--different exponents, crossover behavior, and effects of sample shape and antecedent water content--are reproduced by the model, with similar patterns across experiment and simulation. We conclude both that diffusion is a useful and powerful conceptual model for understanding imbibition, and also that imbibition experiments, being simpler than diffusion measurements, can be used to examine diffusive behavior in rock.

  19. Water Management for Competing Uses: Environmental Flows in the Transboundary Rio Grande/Rio Bravo

    NASA Astrophysics Data System (ADS)

    Sandoval Solis, S.; McKinney, D. C.

    2011-12-01

    Introduction Due to high water demand, the scarcity of water, and the complexity of water allocation, environmental flows have not been considered as an integral part of the water management in the Rio Grande/Rio Bravo transboundary basin. The Big Bend reach is located between the cities of Presidio/Ojinaga to Amistad international reservoir, along the main stream (Fig. 1). Important environmental habitats such as the Big Bend National and State Park in the U.S., the Maderas del Carmen, Cañon de Santa Elena and Ocampo natural reserved areas in Mexico are ecologically threatened because of the lack of environmental water management policies. Several efforts have been undertaken by scientists, government agencies and NGOs to determine the environmental flows for this reach and water management policies that can provide these flows. Objective The objective of this research is to describe a water management policy that can conciliate environmental and human water uses in the Big Bend region. In other words, define a policy that can provide environmental flows without harming water supply for stakeholders or increasing flood risk, within legal and physical constraints of the system. Methodology First, the system was characterized identifying water users, hydraulic infrastructure, and water allocation according to state, federal and international regulations. Second, a hydrograph for environmental flows was proposed that mimics the hydrologic characteristics of the prior dam alteration. Third, a water planning model was constructed to evaluate alternative policies. Fourth, the water management is proposed to provide environmental restoration flows from Luis L. Leon reservoir. This policy considers mechanisms that reduce flooding and drought risks, while meting national and international water regulations. Results Three types of natural flow regimes are considered: (1) median flows aimed to provide the base flow in the region, (2) high flows to provide transversal

  20. Key design factors affecting microbial community composition and pathogenic organism removal in horizontal subsurface flow constructed wetlands.

    PubMed

    Morató, Jordi; Codony, Francesc; Sánchez, Olga; Pérez, Leonardo Martín; García, Joan; Mas, Jordi

    2014-05-15

    Constructed wetlands constitute an interesting option for wastewater reuse since high concentrations of contaminants and pathogenic microorganisms can be removed with these natural treatment systems. In this work, the role of key design factors which could affect microbial removal and wetland performance, such as granular media, water depth and season effect was evaluated in a pilot system consisting of eight parallel horizontal subsurface flow (HSSF) constructed wetlands treating urban wastewater from Les Franqueses del Vallès (Barcelona, Spain). Gravel biofilm as well as influent and effluent water samples of these systems were taken in order to detect the presence of bacterial indicators such as total coliforms (TC), Escherichia coli, fecal enterococci (FE), Clostridium perfringens, and other microbial groups such as Pseudomonas and Aeromonas. The overall microbial inactivation ratio ranged between 1.4 and 2.9 log-units for heterotrophic plate counts (HPC), from 1.2 to 2.2 log units for total coliforms (TC) and from 1.4 to 2.3 log units for E. coli. The presence of fine granulometry strongly influenced the removal of all the bacterial groups analyzed. This effect was significant for TC (p=0.009), E. coli (p=0.004), and FE (p=0.012). Shallow HSSF constructed wetlands were more effective for removing Clostridium spores (p=0.039), and were also more efficient for removing TC (p=0.011) and E. coli (p=0.013) when fine granulometry was used. On the other hand, changes in the total bacterial community from gravel biofilm were examined by using denaturing gradient gel electrophoresis (DGGE) and sequencing of polymerase chain reaction (PCR)-amplified fragments of the 16S rRNA gene recovered from DGGE bands. Cluster analysis of the DGGE banding pattern from the different wetlands showed that microbial assemblages separated according to water depth, and sequences of different phylogenetic groups, such as Alpha, Beta and Delta-Proteobacteria, Nitrospirae, Bacteroidetes

  1. Milk protein composition and stability changes affected by iron in water sources.

    PubMed

    Wang, Aili; Duncan, Susan E; Knowlton, Katharine F; Ray, William K; Dietrich, Andrea M

    2016-06-01

    Water makes up more than 80% of the total weight of milk. However, the influence of water chemistry on the milk proteome has not been extensively studied. The objective was to evaluate interaction of water-sourced iron (low, medium, and high levels) on milk proteome and implications on milk oxidative state and mineral content. Protein composition, oxidative stability, and mineral composition of milk were investigated under conditions of iron ingestion through bovine drinking water (infused) as well as direct iron addition to commercial milk in 2 studies. Four ruminally cannulated cows each received aqueous infusions (based on water consumption of 100L) of 0, 2, 5, and 12.5mg/L Fe(2+) as ferrous lactate, resulting in doses of 0, 200, 500 or 1,250mg of Fe/d, in a 4×4Latin square design for a 14-d period. For comparison, ferrous sulfate solution was directly added into commercial retail milk at the same concentrations: control (0mg of Fe/L), low (2mg of Fe/L), medium (5mg of Fe/L), and high (12.5mg of Fe/L). Two-dimensional electrophoresis coupled with matrix-assisted laser desorption/ionization-tandem time-of-flight (MALDI-TOF/TOF) high-resolution tandem mass spectrometry analysis was applied to characterize milk protein composition. Oxidative stability of milk was evaluated by the thiobarbituric acid reactive substances (TBARS) assay for malondialdehyde, and mineral content was measured by inductively coupled plasma mass spectrometry. For milk from both abomasal infusion of ferrous lactate and direct addition of ferrous sulfate, an iron concentration as low as 2mg of Fe/L was able to cause oxidative stress in dairy cattle and infused milk, respectively. Abomasal infusion affected both caseins and whey proteins in the milk, whereas direct addition mainly influenced caseins. Although abomasal iron infusion did not significantly affect oxidation state and mineral balance (except iron), it induced oxidized off-flavor and partial degradation of whey proteins. Direct

  2. Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

    NASA Astrophysics Data System (ADS)

    Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2015-04-01

    Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying

  3. Application of the methods of gas dynamics to water flows with free surface I : flows with no energy dissipation

    NASA Technical Reports Server (NTRS)

    Preiswerk, Ernst

    1940-01-01

    The application is treated in sufficient detail to facilitate as much as possible its application by the engineer who is less familiar with the subject. The present work was undertaken with two objects in view. In the first place, it is considered as a contribution to the water analogy of gas flows, and secondly, a large portion is devoted to the general theory of the two-dimensional supersonic flows.

  4. Hydrogeology of, and ground-water flow in, a valley-fill and carbonate-rock aquifer system near Long Valley in the New Jersey Highlands

    USGS Publications Warehouse

    Nicholson, R.S.; McAuley, S.D.; Barringer, J.L.; Gordon, A.D.

    1996-01-01

    The hydrogeology of and ground-water flow in a valley-fill and carbonate-rock aquifer system were evaluated by using numerical-modeling techniques and geochemical interpretations to address concerns about the adequacy of the aquifer system to meet increasing demand for water. The study was conducted during 1987-90 by the U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection and Energy. The effects of recent and anticipated ground-water withdrawals on water levels, stream base flows, and water budgets were estimated. Simulation results indicate that recent withdrawals of 4.7 million gallons per day have resulted in water-level declines of up to 35 feet. Under conditions of increases in withdrawals of 121 percent, water levels would decline up to an additional 28 feet. The magnitude of predicted average base-flow depletion, when compared with historic low flows, indicates that projected increases in withdrawals may substantially deplete seasonal low flow of Drakes Brook and South Branch Raritan River. Results of a water-budget analysis indicate that the sources of water to additional supply wells would include leakage from the overlying valley-fill aquifer and induced leakage of surface water into the aquifer system. Results of water-quality analyses indicate that human activities are affecting the quality of the ground water. With the exception of an elevated iron concentration in water from one well, concentrations of inorganic constituents in water from 75 wells did not exceed New Jersey primary or secondary drinking-water regulations. Volatile organic compounds were detected in water from several wells; in two samples, concentrations of specific compounds exceeded drinking-water regulations.

  5. Analysing Thermal Response Test Data Affected by Groundwater Flow and Surface Temperature Change

    NASA Astrophysics Data System (ADS)

    Verdoya, Massimo; Imitazione, Gianmario; Chiozzi, Paolo; Orsi, Marco; Armadillo, Egidio

    2014-05-01

    Tests that record the underground temperature variation due to a constant heat injected into a borehole (or extracted from it) by means of a carrier fluid are routinely performed to infer subsurface thermal conductivity and borehole thermal resistance, which are needed to size geothermal heat pump systems. The most popular model to analyse temperature-time curves obtained from these tests is the infinite line source (ILS). This model gives appropriate estimations of thermal parameters only if particular hydro-geological conditions are fulfilled. Several flaws can however affect data interpretation with ILS, which is based on strong assumptions like those of a purely conductive heat transfer regime in a homogeneous medium, no vertical heat flow and infinite length of the borehole. Other drawbacks can arise from the difficulty in the proper thermal insulation of the test equipment, and consequently with oscillations of the carrier fluid temperature due to surface temperature changes. In this paper, we focused on the treatment of thermal response test data when both advection and periodic changes of surface temperature occur. We used a moving line source model to simulate temperature-time signals under different hypothesis of Darcy velocity and thermal properties. A random noise was added to the signal in order to mimic high frequency disturbances, possibly caused by equipment operating conditions and/or geological variability. The subsurface thermal conductivity, the Darcy velocity and the borehole thermal resistance were inferred by minimising the root mean square error between the synthetic dataset and the theoretical model. The optimisation was carried out with the Nelder-Mead algorithm, and thermal and hydraulic properties were determined by iterative reprocessing according to a trial-and-error procedure. The inferred thermal and hydraulic parameters are well consistent with the 'a priory' values, and the presence of noise in the synthetic data does not produce

  6. Ground-water flow and solute transport at a municipal landfill site on Long Island, New York; Part 2, Simulation of ground-water flow

    USGS Publications Warehouse

    Wexler, E.J.; Maus, P.E.

    1988-01-01

    Data on the hydrogeology of a 26-sq-mi area surrounding the Brookhaven landfill site in central Suffolk County were collected as part of a hydrologic investigation of solute transport from the site. These data were used to develop a steady-state groundwater flow model of the upper glacial (water table) aquifer in the area. The model accounts for the leakage through confining units underlying the aquifer, seepage to streams, recharge from precipitation, and pumpage and redistribution of water. Refined estimates of aquifer and confining-unit properties were obtained through model calibrations. Water table altitudes generated by the calibrated model were used to determine groundwater velocities and probable flow paths in the vicinity of the site under long-term average hydrologic conditions. Groundwater velocities and probable flow paths in the study area were calculated from simulated water table altitudes generated by the calibrated flow model. Groundwater at the center of the site flows southeastward at a velocity of 1.1 ft/d. The report is the second in a three part series describing the hydrologic conditions and groundwater quality, groundwater flow, and solute transport in the vicinity of the Brookhaven landfill. (USGS)

  7. Experimental study on improvement effect of guide wall to water flow in bend of spillway chute.

    PubMed

    Zhang, Qinghua; Diao, Yanfang; Zhai, Xingtao; Li, Shuning

    2016-01-01

    In order to improve water flow in a bend of a spillway chute using a guide wall, modeling experiments with or without a guide wall under conditions of three different bend axial radii, three chute bottom slopes and three flow rates were carried out in this study. Two indexes were calculated, which are the improved water surface uniformity and the reduced rate of water surface difference in concave and convex banks of the cross-section. The results show that: (1) setting a guide wall in a bend can improve water flow in the bend because it increased the water surface uniformity of the cross-section and reduced the water surface difference in the concave and convex banks; (2) the smaller the bend axial radius, the better the water surface improvement effect will be using a guide wall; (3) the steeper the bottom slope, the more cross-sections with less water surface difference; and (4) flow rates have a great influence on water surface improvement in the bend, and the guide wall can improve water flow obviously when the water depth in the starting section of the bend is lower than the height of the guide wall. This study has important implications in engineering design of guide walls. PMID:26877052

  8. Against the flow: chemical detection of downstream predators in running waters

    PubMed Central

    Dahl, J.; Nilsson, P. A.; Petersson, L. B.

    1998-01-01

    In running waters, chemical cues have generally been assumed to always come from upstream locations. Here, we present field and laboratory evidence that Gammarus pulex can use chemical cues from downstream predators to adaptively adjust drifting behaviour. In the field, significantly fewer Gammarus migrated into stream enclosures where brown trout (Salmo trutta) were present than into control enclosures. In a subsequent laboratory experiment, Gammarus actively avoided live trout and trout chemicals placed downstream in an artificial stream, whereas no effects were found in response to control or visual cues. We suggest that the mechanism explaining the ability of Gammarus to detect downstream predators is use of backflows, which locally transport fish chemicals against the main flow. Such backflows are both created by the Gammarus itself and by surrounding substrate heterogeneity. These results profoundly affect the way in which we view the chemical environment of running waters and have important implications for empirical and theoretical work evaluating predator effects in running waters, as they demonstrate that prey immigration rates can depend on downstream predator densities.

  9. Ground-water flow paths and traveltime to three small embayments within the Peconic Estuary, eastern Suffolk County, New York

    USGS Publications Warehouse

    Schubert, Christopher E.

    1999-01-01

    The Peconic Estuary, at the eastern end of Long Island, has been plagued by a recurrent algal bloom that has caused the severe decline of local marine resources. Although the onset, duration, and cessation of the bloom remain unpredictable, ground-water discharge has been shown to affect surface-water quality in the western part of the estuary. Results from a study on the North Fork of Long Island indicate that local hydrogeologic factors cause differences in ground-water age and characteristics of discharge to the estuary. The need for information on the local patterns and rates of ground-water discharge to the Peconic Estuary prompted analysis of ground-water flow paths and traveltime to three small embayments within the estuary.Meetinghouse Creek, near the west end of the North Fork; Sag Harbor Cove, in the central part of the South Fork; and West Neck Bay, on Shelter Island. Ground-water-flow models were developed, and particle-tracking procedures were applied to the results of each model, to define the flow paths and traveltime of ground water to the three embayments. The steady-state flow models represent the two-dimensional ground-water-flow system along a vertical section through the uplands of each embayment and simulate long-term hydrologic conditions. The particle-tracking procedure used model-generated ground-water levels and flow rates to calculate the water-particle pathlines and times-of-travel through each flow system from the point of entry (recharge) to the point of exit at streams, the shore, or subsea-discharge areas. Results for the Meetinghouse Creek study area indicate that about 50 percent of the total recharge that enters the system flows southward to Meetinghouse Creek; half of this amount discharges as base flow to the fresh-water reach of the creek, and half as shoreline underflow to the estuarine reach. About 85 percent of the total discharge to Meetinghouse Creek has flowed entirely within the upper glacial aquifer, and about 15

  10. Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

    NASA Astrophysics Data System (ADS)

    Mueller, M. H.; Weingartner, R.; Alewell, C.

    2013-04-01<